Index: llvm/trunk/bindings/python/llvm/core.py =================================================================== --- llvm/trunk/bindings/python/llvm/core.py +++ llvm/trunk/bindings/python/llvm/core.py @@ -465,9 +465,6 @@ library.LLVMInitializeAnalysis.argtypes = [PassRegistry] library.LLVMInitializeAnalysis.restype = None - library.LLVMInitializeIPA.argtypes = [PassRegistry] - library.LLVMInitializeIPA.restype = None - library.LLVMInitializeCodeGen.argtypes = [PassRegistry] library.LLVMInitializeCodeGen.restype = None @@ -621,7 +618,6 @@ lib.LLVMInitializeIPO(p) lib.LLVMInitializeInstrumentation(p) lib.LLVMInitializeAnalysis(p) - lib.LLVMInitializeIPA(p) lib.LLVMInitializeCodeGen(p) lib.LLVMInitializeTarget(p) Index: llvm/trunk/include/llvm/InitializePasses.h =================================================================== --- llvm/trunk/include/llvm/InitializePasses.h +++ llvm/trunk/include/llvm/InitializePasses.h @@ -53,9 +53,6 @@ /// initializeAnalysis - Initialize all passes linked into the Analysis library. void initializeAnalysis(PassRegistry&); -/// initializeIPA - Initialize all passes linked into the IPA library. -void initializeIPA(PassRegistry&); - /// initializeCodeGen - Initialize all passes linked into the CodeGen library. void initializeCodeGen(PassRegistry&); Index: llvm/trunk/lib/Analysis/Analysis.cpp =================================================================== --- llvm/trunk/lib/Analysis/Analysis.cpp +++ llvm/trunk/lib/Analysis/Analysis.cpp @@ -28,6 +28,9 @@ initializeBasicAliasAnalysisPass(Registry); initializeBlockFrequencyInfoWrapperPassPass(Registry); initializeBranchProbabilityInfoWrapperPassPass(Registry); + initializeCallGraphWrapperPassPass(Registry); + initializeCallGraphPrinterPass(Registry); + initializeCallGraphViewerPass(Registry); initializeCostModelAnalysisPass(Registry); initializeCFGViewerPass(Registry); initializeCFGPrinterPass(Registry); @@ -47,6 +50,7 @@ initializePostDomPrinterPass(Registry); initializePostDomOnlyViewerPass(Registry); initializePostDomOnlyPrinterPass(Registry); + initializeGlobalsModRefPass(Registry); initializeIVUsersPass(Registry); initializeInstCountPass(Registry); initializeIntervalPartitionPass(Registry); @@ -74,6 +78,10 @@ initializeAnalysis(*unwrap(R)); } +void LLVMInitializeIPA(LLVMPassRegistryRef R) { + initializeAnalysis(*unwrap(R)); +} + LLVMBool LLVMVerifyModule(LLVMModuleRef M, LLVMVerifierFailureAction Action, char **OutMessages) { raw_ostream *DebugOS = Action != LLVMReturnStatusAction ? &errs() : nullptr; Index: llvm/trunk/lib/Analysis/CMakeLists.txt =================================================================== --- llvm/trunk/lib/Analysis/CMakeLists.txt +++ llvm/trunk/lib/Analysis/CMakeLists.txt @@ -13,6 +13,9 @@ CFGPrinter.cpp CFLAliasAnalysis.cpp CGSCCPassManager.cpp + CallGraph.cpp + CallGraphSCCPass.cpp + CallPrinter.cpp CaptureTracking.cpp CostModel.cpp CodeMetrics.cpp @@ -23,7 +26,9 @@ DivergenceAnalysis.cpp DomPrinter.cpp DominanceFrontier.cpp + GlobalsModRef.cpp IVUsers.cpp + InlineCost.cpp InstCount.cpp InstructionSimplify.cpp Interval.cpp @@ -69,5 +74,3 @@ ) add_dependencies(LLVMAnalysis intrinsics_gen) - -add_subdirectory(IPA) Index: llvm/trunk/lib/Analysis/CallGraph.cpp =================================================================== --- llvm/trunk/lib/Analysis/CallGraph.cpp +++ llvm/trunk/lib/Analysis/CallGraph.cpp @@ -0,0 +1,309 @@ +//===- CallGraph.cpp - Build a Module's call graph ------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Analysis/CallGraph.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/Module.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" +using namespace llvm; + +//===----------------------------------------------------------------------===// +// Implementations of the CallGraph class methods. +// + +CallGraph::CallGraph(Module &M) + : M(M), Root(nullptr), ExternalCallingNode(getOrInsertFunction(nullptr)), + CallsExternalNode(llvm::make_unique(nullptr)) { + // Add every function to the call graph. + for (Function &F : M) + addToCallGraph(&F); + + // If we didn't find a main function, use the external call graph node + if (!Root) + Root = ExternalCallingNode; +} + +CallGraph::CallGraph(CallGraph &&Arg) + : M(Arg.M), FunctionMap(std::move(Arg.FunctionMap)), Root(Arg.Root), + ExternalCallingNode(Arg.ExternalCallingNode), + CallsExternalNode(std::move(Arg.CallsExternalNode)) { + Arg.FunctionMap.clear(); + Arg.Root = nullptr; + Arg.ExternalCallingNode = nullptr; +} + +CallGraph::~CallGraph() { + // CallsExternalNode is not in the function map, delete it explicitly. + if (CallsExternalNode) + CallsExternalNode->allReferencesDropped(); + +// Reset all node's use counts to zero before deleting them to prevent an +// assertion from firing. +#ifndef NDEBUG + for (auto &I : FunctionMap) + I.second->allReferencesDropped(); +#endif +} + +void CallGraph::addToCallGraph(Function *F) { + CallGraphNode *Node = getOrInsertFunction(F); + + // If this function has external linkage, anything could call it. + if (!F->hasLocalLinkage()) { + ExternalCallingNode->addCalledFunction(CallSite(), Node); + + // Found the entry point? + if (F->getName() == "main") { + if (Root) // Found multiple external mains? Don't pick one. + Root = ExternalCallingNode; + else + Root = Node; // Found a main, keep track of it! + } + } + + // If this function has its address taken, anything could call it. + if (F->hasAddressTaken()) + ExternalCallingNode->addCalledFunction(CallSite(), Node); + + // If this function is not defined in this translation unit, it could call + // anything. + if (F->isDeclaration() && !F->isIntrinsic()) + Node->addCalledFunction(CallSite(), CallsExternalNode.get()); + + // Look for calls by this function. + for (Function::iterator BB = F->begin(), BBE = F->end(); BB != BBE; ++BB) + for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE; + ++II) { + CallSite CS(cast(II)); + if (CS) { + const Function *Callee = CS.getCalledFunction(); + if (!Callee || !Intrinsic::isLeaf(Callee->getIntrinsicID())) + // Indirect calls of intrinsics are not allowed so no need to check. + // We can be more precise here by using TargetArg returned by + // Intrinsic::isLeaf. + Node->addCalledFunction(CS, CallsExternalNode.get()); + else if (!Callee->isIntrinsic()) + Node->addCalledFunction(CS, getOrInsertFunction(Callee)); + } + } +} + +void CallGraph::print(raw_ostream &OS) const { + OS << "CallGraph Root is: "; + if (Function *F = Root->getFunction()) + OS << F->getName() << "\n"; + else { + OS << "<>\n"; + } + + // Print in a deterministic order by sorting CallGraphNodes by name. We do + // this here to avoid slowing down the non-printing fast path. + + SmallVector Nodes; + Nodes.reserve(FunctionMap.size()); + + for (auto I = begin(), E = end(); I != E; ++I) + Nodes.push_back(I->second.get()); + + std::sort(Nodes.begin(), Nodes.end(), + [](CallGraphNode *LHS, CallGraphNode *RHS) { + if (Function *LF = LHS->getFunction()) + if (Function *RF = RHS->getFunction()) + return LF->getName() < RF->getName(); + + return RHS->getFunction() != nullptr; + }); + + for (CallGraphNode *CN : Nodes) + CN->print(OS); +} + +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +void CallGraph::dump() const { print(dbgs()); } +#endif + +// removeFunctionFromModule - Unlink the function from this module, returning +// it. Because this removes the function from the module, the call graph node +// is destroyed. This is only valid if the function does not call any other +// functions (ie, there are no edges in it's CGN). The easiest way to do this +// is to dropAllReferences before calling this. +// +Function *CallGraph::removeFunctionFromModule(CallGraphNode *CGN) { + assert(CGN->empty() && "Cannot remove function from call " + "graph if it references other functions!"); + Function *F = CGN->getFunction(); // Get the function for the call graph node + FunctionMap.erase(F); // Remove the call graph node from the map + + M.getFunctionList().remove(F); + return F; +} + +/// spliceFunction - Replace the function represented by this node by another. +/// This does not rescan the body of the function, so it is suitable when +/// splicing the body of the old function to the new while also updating all +/// callers from old to new. +/// +void CallGraph::spliceFunction(const Function *From, const Function *To) { + assert(FunctionMap.count(From) && "No CallGraphNode for function!"); + assert(!FunctionMap.count(To) && + "Pointing CallGraphNode at a function that already exists"); + FunctionMapTy::iterator I = FunctionMap.find(From); + I->second->F = const_cast(To); + FunctionMap[To] = std::move(I->second); + FunctionMap.erase(I); +} + +// getOrInsertFunction - This method is identical to calling operator[], but +// it will insert a new CallGraphNode for the specified function if one does +// not already exist. +CallGraphNode *CallGraph::getOrInsertFunction(const Function *F) { + auto &CGN = FunctionMap[F]; + if (CGN) + return CGN.get(); + + assert((!F || F->getParent() == &M) && "Function not in current module!"); + CGN = llvm::make_unique(const_cast(F)); + return CGN.get(); +} + +//===----------------------------------------------------------------------===// +// Implementations of the CallGraphNode class methods. +// + +void CallGraphNode::print(raw_ostream &OS) const { + if (Function *F = getFunction()) + OS << "Call graph node for function: '" << F->getName() << "'"; + else + OS << "Call graph node <>"; + + OS << "<<" << this << ">> #uses=" << getNumReferences() << '\n'; + + for (const_iterator I = begin(), E = end(); I != E; ++I) { + OS << " CS<" << I->first << "> calls "; + if (Function *FI = I->second->getFunction()) + OS << "function '" << FI->getName() <<"'\n"; + else + OS << "external node\n"; + } + OS << '\n'; +} + +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +void CallGraphNode::dump() const { print(dbgs()); } +#endif + +/// removeCallEdgeFor - This method removes the edge in the node for the +/// specified call site. Note that this method takes linear time, so it +/// should be used sparingly. +void CallGraphNode::removeCallEdgeFor(CallSite CS) { + for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) { + assert(I != CalledFunctions.end() && "Cannot find callsite to remove!"); + if (I->first == CS.getInstruction()) { + I->second->DropRef(); + *I = CalledFunctions.back(); + CalledFunctions.pop_back(); + return; + } + } +} + +// removeAnyCallEdgeTo - This method removes any call edges from this node to +// the specified callee function. This takes more time to execute than +// removeCallEdgeTo, so it should not be used unless necessary. +void CallGraphNode::removeAnyCallEdgeTo(CallGraphNode *Callee) { + for (unsigned i = 0, e = CalledFunctions.size(); i != e; ++i) + if (CalledFunctions[i].second == Callee) { + Callee->DropRef(); + CalledFunctions[i] = CalledFunctions.back(); + CalledFunctions.pop_back(); + --i; --e; + } +} + +/// removeOneAbstractEdgeTo - Remove one edge associated with a null callsite +/// from this node to the specified callee function. +void CallGraphNode::removeOneAbstractEdgeTo(CallGraphNode *Callee) { + for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) { + assert(I != CalledFunctions.end() && "Cannot find callee to remove!"); + CallRecord &CR = *I; + if (CR.second == Callee && CR.first == nullptr) { + Callee->DropRef(); + *I = CalledFunctions.back(); + CalledFunctions.pop_back(); + return; + } + } +} + +/// replaceCallEdge - This method replaces the edge in the node for the +/// specified call site with a new one. Note that this method takes linear +/// time, so it should be used sparingly. +void CallGraphNode::replaceCallEdge(CallSite CS, + CallSite NewCS, CallGraphNode *NewNode){ + for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) { + assert(I != CalledFunctions.end() && "Cannot find callsite to remove!"); + if (I->first == CS.getInstruction()) { + I->second->DropRef(); + I->first = NewCS.getInstruction(); + I->second = NewNode; + NewNode->AddRef(); + return; + } + } +} + +//===----------------------------------------------------------------------===// +// Out-of-line definitions of CallGraphAnalysis class members. +// + +char CallGraphAnalysis::PassID; + +//===----------------------------------------------------------------------===// +// Implementations of the CallGraphWrapperPass class methods. +// + +CallGraphWrapperPass::CallGraphWrapperPass() : ModulePass(ID) { + initializeCallGraphWrapperPassPass(*PassRegistry::getPassRegistry()); +} + +CallGraphWrapperPass::~CallGraphWrapperPass() {} + +void CallGraphWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesAll(); +} + +bool CallGraphWrapperPass::runOnModule(Module &M) { + // All the real work is done in the constructor for the CallGraph. + G.reset(new CallGraph(M)); + return false; +} + +INITIALIZE_PASS(CallGraphWrapperPass, "basiccg", "CallGraph Construction", + false, true) + +char CallGraphWrapperPass::ID = 0; + +void CallGraphWrapperPass::releaseMemory() { G.reset(); } + +void CallGraphWrapperPass::print(raw_ostream &OS, const Module *) const { + if (!G) { + OS << "No call graph has been built!\n"; + return; + } + + // Just delegate. + G->print(OS); +} + +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +void CallGraphWrapperPass::dump() const { print(dbgs(), nullptr); } +#endif Index: llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp =================================================================== --- llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp +++ llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp @@ -0,0 +1,632 @@ +//===- CallGraphSCCPass.cpp - Pass that operates BU on call graph ---------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the CallGraphSCCPass class, which is used for passes +// which are implemented as bottom-up traversals on the call graph. Because +// there may be cycles in the call graph, passes of this type operate on the +// call-graph in SCC order: that is, they process function bottom-up, except for +// recursive functions, which they process all at once. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Analysis/CallGraphSCCPass.h" +#include "llvm/ADT/SCCIterator.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/Analysis/CallGraph.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/LegacyPassManagers.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/Timer.h" +#include "llvm/Support/raw_ostream.h" +using namespace llvm; + +#define DEBUG_TYPE "cgscc-passmgr" + +static cl::opt +MaxIterations("max-cg-scc-iterations", cl::ReallyHidden, cl::init(4)); + +STATISTIC(MaxSCCIterations, "Maximum CGSCCPassMgr iterations on one SCC"); + +//===----------------------------------------------------------------------===// +// CGPassManager +// +/// CGPassManager manages FPPassManagers and CallGraphSCCPasses. + +namespace { + +class CGPassManager : public ModulePass, public PMDataManager { +public: + static char ID; + explicit CGPassManager() + : ModulePass(ID), PMDataManager() { } + + /// Execute all of the passes scheduled for execution. Keep track of + /// whether any of the passes modifies the module, and if so, return true. + bool runOnModule(Module &M) override; + + using ModulePass::doInitialization; + using ModulePass::doFinalization; + + bool doInitialization(CallGraph &CG); + bool doFinalization(CallGraph &CG); + + /// Pass Manager itself does not invalidate any analysis info. + void getAnalysisUsage(AnalysisUsage &Info) const override { + // CGPassManager walks SCC and it needs CallGraph. + Info.addRequired(); + Info.setPreservesAll(); + } + + const char *getPassName() const override { + return "CallGraph Pass Manager"; + } + + PMDataManager *getAsPMDataManager() override { return this; } + Pass *getAsPass() override { return this; } + + // Print passes managed by this manager + void dumpPassStructure(unsigned Offset) override { + errs().indent(Offset*2) << "Call Graph SCC Pass Manager\n"; + for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) { + Pass *P = getContainedPass(Index); + P->dumpPassStructure(Offset + 1); + dumpLastUses(P, Offset+1); + } + } + + Pass *getContainedPass(unsigned N) { + assert(N < PassVector.size() && "Pass number out of range!"); + return static_cast(PassVector[N]); + } + + PassManagerType getPassManagerType() const override { + return PMT_CallGraphPassManager; + } + +private: + bool RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG, + bool &DevirtualizedCall); + + bool RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC, + CallGraph &CG, bool &CallGraphUpToDate, + bool &DevirtualizedCall); + bool RefreshCallGraph(CallGraphSCC &CurSCC, CallGraph &CG, + bool IsCheckingMode); +}; + +} // end anonymous namespace. + +char CGPassManager::ID = 0; + + +bool CGPassManager::RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC, + CallGraph &CG, bool &CallGraphUpToDate, + bool &DevirtualizedCall) { + bool Changed = false; + PMDataManager *PM = P->getAsPMDataManager(); + + if (!PM) { + CallGraphSCCPass *CGSP = (CallGraphSCCPass*)P; + if (!CallGraphUpToDate) { + DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, false); + CallGraphUpToDate = true; + } + + { + TimeRegion PassTimer(getPassTimer(CGSP)); + Changed = CGSP->runOnSCC(CurSCC); + } + + // After the CGSCCPass is done, when assertions are enabled, use + // RefreshCallGraph to verify that the callgraph was correctly updated. +#ifndef NDEBUG + if (Changed) + RefreshCallGraph(CurSCC, CG, true); +#endif + + return Changed; + } + + + assert(PM->getPassManagerType() == PMT_FunctionPassManager && + "Invalid CGPassManager member"); + FPPassManager *FPP = (FPPassManager*)P; + + // Run pass P on all functions in the current SCC. + for (CallGraphNode *CGN : CurSCC) { + if (Function *F = CGN->getFunction()) { + dumpPassInfo(P, EXECUTION_MSG, ON_FUNCTION_MSG, F->getName()); + { + TimeRegion PassTimer(getPassTimer(FPP)); + Changed |= FPP->runOnFunction(*F); + } + F->getContext().yield(); + } + } + + // The function pass(es) modified the IR, they may have clobbered the + // callgraph. + if (Changed && CallGraphUpToDate) { + DEBUG(dbgs() << "CGSCCPASSMGR: Pass Dirtied SCC: " + << P->getPassName() << '\n'); + CallGraphUpToDate = false; + } + return Changed; +} + + +/// Scan the functions in the specified CFG and resync the +/// callgraph with the call sites found in it. This is used after +/// FunctionPasses have potentially munged the callgraph, and can be used after +/// CallGraphSCC passes to verify that they correctly updated the callgraph. +/// +/// This function returns true if it devirtualized an existing function call, +/// meaning it turned an indirect call into a direct call. This happens when +/// a function pass like GVN optimizes away stuff feeding the indirect call. +/// This never happens in checking mode. +/// +bool CGPassManager::RefreshCallGraph(CallGraphSCC &CurSCC, + CallGraph &CG, bool CheckingMode) { + DenseMap CallSites; + + DEBUG(dbgs() << "CGSCCPASSMGR: Refreshing SCC with " << CurSCC.size() + << " nodes:\n"; + for (CallGraphNode *CGN : CurSCC) + CGN->dump(); + ); + + bool MadeChange = false; + bool DevirtualizedCall = false; + + // Scan all functions in the SCC. + unsigned FunctionNo = 0; + for (CallGraphSCC::iterator SCCIdx = CurSCC.begin(), E = CurSCC.end(); + SCCIdx != E; ++SCCIdx, ++FunctionNo) { + CallGraphNode *CGN = *SCCIdx; + Function *F = CGN->getFunction(); + if (!F || F->isDeclaration()) continue; + + // Walk the function body looking for call sites. Sync up the call sites in + // CGN with those actually in the function. + + // Keep track of the number of direct and indirect calls that were + // invalidated and removed. + unsigned NumDirectRemoved = 0, NumIndirectRemoved = 0; + + // Get the set of call sites currently in the function. + for (CallGraphNode::iterator I = CGN->begin(), E = CGN->end(); I != E; ) { + // If this call site is null, then the function pass deleted the call + // entirely and the WeakVH nulled it out. + if (!I->first || + // If we've already seen this call site, then the FunctionPass RAUW'd + // one call with another, which resulted in two "uses" in the edge + // list of the same call. + CallSites.count(I->first) || + + // If the call edge is not from a call or invoke, or it is a + // instrinsic call, then the function pass RAUW'd a call with + // another value. This can happen when constant folding happens + // of well known functions etc. + !CallSite(I->first) || + (CallSite(I->first).getCalledFunction() && + CallSite(I->first).getCalledFunction()->isIntrinsic() && + Intrinsic::isLeaf( + CallSite(I->first).getCalledFunction()->getIntrinsicID()))) { + assert(!CheckingMode && + "CallGraphSCCPass did not update the CallGraph correctly!"); + + // If this was an indirect call site, count it. + if (!I->second->getFunction()) + ++NumIndirectRemoved; + else + ++NumDirectRemoved; + + // Just remove the edge from the set of callees, keep track of whether + // I points to the last element of the vector. + bool WasLast = I + 1 == E; + CGN->removeCallEdge(I); + + // If I pointed to the last element of the vector, we have to bail out: + // iterator checking rejects comparisons of the resultant pointer with + // end. + if (WasLast) + break; + E = CGN->end(); + continue; + } + + assert(!CallSites.count(I->first) && + "Call site occurs in node multiple times"); + + CallSite CS(I->first); + if (CS) { + Function *Callee = CS.getCalledFunction(); + // Ignore intrinsics because they're not really function calls. + if (!Callee || !(Callee->isIntrinsic())) + CallSites.insert(std::make_pair(I->first, I->second)); + } + ++I; + } + + // Loop over all of the instructions in the function, getting the callsites. + // Keep track of the number of direct/indirect calls added. + unsigned NumDirectAdded = 0, NumIndirectAdded = 0; + + for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) + for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { + CallSite CS(cast(I)); + if (!CS) continue; + Function *Callee = CS.getCalledFunction(); + if (Callee && Callee->isIntrinsic()) continue; + + // If this call site already existed in the callgraph, just verify it + // matches up to expectations and remove it from CallSites. + DenseMap::iterator ExistingIt = + CallSites.find(CS.getInstruction()); + if (ExistingIt != CallSites.end()) { + CallGraphNode *ExistingNode = ExistingIt->second; + + // Remove from CallSites since we have now seen it. + CallSites.erase(ExistingIt); + + // Verify that the callee is right. + if (ExistingNode->getFunction() == CS.getCalledFunction()) + continue; + + // If we are in checking mode, we are not allowed to actually mutate + // the callgraph. If this is a case where we can infer that the + // callgraph is less precise than it could be (e.g. an indirect call + // site could be turned direct), don't reject it in checking mode, and + // don't tweak it to be more precise. + if (CheckingMode && CS.getCalledFunction() && + ExistingNode->getFunction() == nullptr) + continue; + + assert(!CheckingMode && + "CallGraphSCCPass did not update the CallGraph correctly!"); + + // If not, we either went from a direct call to indirect, indirect to + // direct, or direct to different direct. + CallGraphNode *CalleeNode; + if (Function *Callee = CS.getCalledFunction()) { + CalleeNode = CG.getOrInsertFunction(Callee); + // Keep track of whether we turned an indirect call into a direct + // one. + if (!ExistingNode->getFunction()) { + DevirtualizedCall = true; + DEBUG(dbgs() << " CGSCCPASSMGR: Devirtualized call to '" + << Callee->getName() << "'\n"); + } + } else { + CalleeNode = CG.getCallsExternalNode(); + } + + // Update the edge target in CGN. + CGN->replaceCallEdge(CS, CS, CalleeNode); + MadeChange = true; + continue; + } + + assert(!CheckingMode && + "CallGraphSCCPass did not update the CallGraph correctly!"); + + // If the call site didn't exist in the CGN yet, add it. + CallGraphNode *CalleeNode; + if (Function *Callee = CS.getCalledFunction()) { + CalleeNode = CG.getOrInsertFunction(Callee); + ++NumDirectAdded; + } else { + CalleeNode = CG.getCallsExternalNode(); + ++NumIndirectAdded; + } + + CGN->addCalledFunction(CS, CalleeNode); + MadeChange = true; + } + + // We scanned the old callgraph node, removing invalidated call sites and + // then added back newly found call sites. One thing that can happen is + // that an old indirect call site was deleted and replaced with a new direct + // call. In this case, we have devirtualized a call, and CGSCCPM would like + // to iteratively optimize the new code. Unfortunately, we don't really + // have a great way to detect when this happens. As an approximation, we + // just look at whether the number of indirect calls is reduced and the + // number of direct calls is increased. There are tons of ways to fool this + // (e.g. DCE'ing an indirect call and duplicating an unrelated block with a + // direct call) but this is close enough. + if (NumIndirectRemoved > NumIndirectAdded && + NumDirectRemoved < NumDirectAdded) + DevirtualizedCall = true; + + // After scanning this function, if we still have entries in callsites, then + // they are dangling pointers. WeakVH should save us for this, so abort if + // this happens. + assert(CallSites.empty() && "Dangling pointers found in call sites map"); + + // Periodically do an explicit clear to remove tombstones when processing + // large scc's. + if ((FunctionNo & 15) == 15) + CallSites.clear(); + } + + DEBUG(if (MadeChange) { + dbgs() << "CGSCCPASSMGR: Refreshed SCC is now:\n"; + for (CallGraphNode *CGN : CurSCC) + CGN->dump(); + if (DevirtualizedCall) + dbgs() << "CGSCCPASSMGR: Refresh devirtualized a call!\n"; + + } else { + dbgs() << "CGSCCPASSMGR: SCC Refresh didn't change call graph.\n"; + } + ); + (void)MadeChange; + + return DevirtualizedCall; +} + +/// Execute the body of the entire pass manager on the specified SCC. +/// This keeps track of whether a function pass devirtualizes +/// any calls and returns it in DevirtualizedCall. +bool CGPassManager::RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG, + bool &DevirtualizedCall) { + bool Changed = false; + + // Keep track of whether the callgraph is known to be up-to-date or not. + // The CGSSC pass manager runs two types of passes: + // CallGraphSCC Passes and other random function passes. Because other + // random function passes are not CallGraph aware, they may clobber the + // call graph by introducing new calls or deleting other ones. This flag + // is set to false when we run a function pass so that we know to clean up + // the callgraph when we need to run a CGSCCPass again. + bool CallGraphUpToDate = true; + + // Run all passes on current SCC. + for (unsigned PassNo = 0, e = getNumContainedPasses(); + PassNo != e; ++PassNo) { + Pass *P = getContainedPass(PassNo); + + // If we're in -debug-pass=Executions mode, construct the SCC node list, + // otherwise avoid constructing this string as it is expensive. + if (isPassDebuggingExecutionsOrMore()) { + std::string Functions; + #ifndef NDEBUG + raw_string_ostream OS(Functions); + for (CallGraphSCC::iterator I = CurSCC.begin(), E = CurSCC.end(); + I != E; ++I) { + if (I != CurSCC.begin()) OS << ", "; + (*I)->print(OS); + } + OS.flush(); + #endif + dumpPassInfo(P, EXECUTION_MSG, ON_CG_MSG, Functions); + } + dumpRequiredSet(P); + + initializeAnalysisImpl(P); + + // Actually run this pass on the current SCC. + Changed |= RunPassOnSCC(P, CurSCC, CG, + CallGraphUpToDate, DevirtualizedCall); + + if (Changed) + dumpPassInfo(P, MODIFICATION_MSG, ON_CG_MSG, ""); + dumpPreservedSet(P); + + verifyPreservedAnalysis(P); + removeNotPreservedAnalysis(P); + recordAvailableAnalysis(P); + removeDeadPasses(P, "", ON_CG_MSG); + } + + // If the callgraph was left out of date (because the last pass run was a + // functionpass), refresh it before we move on to the next SCC. + if (!CallGraphUpToDate) + DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, false); + return Changed; +} + +/// Execute all of the passes scheduled for execution. Keep track of +/// whether any of the passes modifies the module, and if so, return true. +bool CGPassManager::runOnModule(Module &M) { + CallGraph &CG = getAnalysis().getCallGraph(); + bool Changed = doInitialization(CG); + + // Walk the callgraph in bottom-up SCC order. + scc_iterator CGI = scc_begin(&CG); + + CallGraphSCC CurSCC(&CGI); + while (!CGI.isAtEnd()) { + // Copy the current SCC and increment past it so that the pass can hack + // on the SCC if it wants to without invalidating our iterator. + const std::vector &NodeVec = *CGI; + CurSCC.initialize(NodeVec.data(), NodeVec.data() + NodeVec.size()); + ++CGI; + + // At the top level, we run all the passes in this pass manager on the + // functions in this SCC. However, we support iterative compilation in the + // case where a function pass devirtualizes a call to a function. For + // example, it is very common for a function pass (often GVN or instcombine) + // to eliminate the addressing that feeds into a call. With that improved + // information, we would like the call to be an inline candidate, infer + // mod-ref information etc. + // + // Because of this, we allow iteration up to a specified iteration count. + // This only happens in the case of a devirtualized call, so we only burn + // compile time in the case that we're making progress. We also have a hard + // iteration count limit in case there is crazy code. + unsigned Iteration = 0; + bool DevirtualizedCall = false; + do { + DEBUG(if (Iteration) + dbgs() << " SCCPASSMGR: Re-visiting SCC, iteration #" + << Iteration << '\n'); + DevirtualizedCall = false; + Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall); + } while (Iteration++ < MaxIterations && DevirtualizedCall); + + if (DevirtualizedCall) + DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after " << Iteration + << " times, due to -max-cg-scc-iterations\n"); + + if (Iteration > MaxSCCIterations) + MaxSCCIterations = Iteration; + + } + Changed |= doFinalization(CG); + return Changed; +} + + +/// Initialize CG +bool CGPassManager::doInitialization(CallGraph &CG) { + bool Changed = false; + for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) { + if (PMDataManager *PM = getContainedPass(i)->getAsPMDataManager()) { + assert(PM->getPassManagerType() == PMT_FunctionPassManager && + "Invalid CGPassManager member"); + Changed |= ((FPPassManager*)PM)->doInitialization(CG.getModule()); + } else { + Changed |= ((CallGraphSCCPass*)getContainedPass(i))->doInitialization(CG); + } + } + return Changed; +} + +/// Finalize CG +bool CGPassManager::doFinalization(CallGraph &CG) { + bool Changed = false; + for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) { + if (PMDataManager *PM = getContainedPass(i)->getAsPMDataManager()) { + assert(PM->getPassManagerType() == PMT_FunctionPassManager && + "Invalid CGPassManager member"); + Changed |= ((FPPassManager*)PM)->doFinalization(CG.getModule()); + } else { + Changed |= ((CallGraphSCCPass*)getContainedPass(i))->doFinalization(CG); + } + } + return Changed; +} + +//===----------------------------------------------------------------------===// +// CallGraphSCC Implementation +//===----------------------------------------------------------------------===// + +/// This informs the SCC and the pass manager that the specified +/// Old node has been deleted, and New is to be used in its place. +void CallGraphSCC::ReplaceNode(CallGraphNode *Old, CallGraphNode *New) { + assert(Old != New && "Should not replace node with self"); + for (unsigned i = 0; ; ++i) { + assert(i != Nodes.size() && "Node not in SCC"); + if (Nodes[i] != Old) continue; + Nodes[i] = New; + break; + } + + // Update the active scc_iterator so that it doesn't contain dangling + // pointers to the old CallGraphNode. + scc_iterator *CGI = (scc_iterator*)Context; + CGI->ReplaceNode(Old, New); +} + + +//===----------------------------------------------------------------------===// +// CallGraphSCCPass Implementation +//===----------------------------------------------------------------------===// + +/// Assign pass manager to manage this pass. +void CallGraphSCCPass::assignPassManager(PMStack &PMS, + PassManagerType PreferredType) { + // Find CGPassManager + while (!PMS.empty() && + PMS.top()->getPassManagerType() > PMT_CallGraphPassManager) + PMS.pop(); + + assert(!PMS.empty() && "Unable to handle Call Graph Pass"); + CGPassManager *CGP; + + if (PMS.top()->getPassManagerType() == PMT_CallGraphPassManager) + CGP = (CGPassManager*)PMS.top(); + else { + // Create new Call Graph SCC Pass Manager if it does not exist. + assert(!PMS.empty() && "Unable to create Call Graph Pass Manager"); + PMDataManager *PMD = PMS.top(); + + // [1] Create new Call Graph Pass Manager + CGP = new CGPassManager(); + + // [2] Set up new manager's top level manager + PMTopLevelManager *TPM = PMD->getTopLevelManager(); + TPM->addIndirectPassManager(CGP); + + // [3] Assign manager to manage this new manager. This may create + // and push new managers into PMS + Pass *P = CGP; + TPM->schedulePass(P); + + // [4] Push new manager into PMS + PMS.push(CGP); + } + + CGP->add(this); +} + +/// For this class, we declare that we require and preserve the call graph. +/// If the derived class implements this method, it should +/// always explicitly call the implementation here. +void CallGraphSCCPass::getAnalysisUsage(AnalysisUsage &AU) const { + AU.addRequired(); + AU.addPreserved(); +} + + +//===----------------------------------------------------------------------===// +// PrintCallGraphPass Implementation +//===----------------------------------------------------------------------===// + +namespace { + /// PrintCallGraphPass - Print a Module corresponding to a call graph. + /// + class PrintCallGraphPass : public CallGraphSCCPass { + std::string Banner; + raw_ostream &Out; // raw_ostream to print on. + + public: + static char ID; + PrintCallGraphPass(const std::string &B, raw_ostream &o) + : CallGraphSCCPass(ID), Banner(B), Out(o) {} + + void getAnalysisUsage(AnalysisUsage &AU) const override { + AU.setPreservesAll(); + } + + bool runOnSCC(CallGraphSCC &SCC) override { + Out << Banner; + for (CallGraphNode *CGN : SCC) { + if (CGN->getFunction()) + CGN->getFunction()->print(Out); + else + Out << "\nPrinting Function\n"; + } + return false; + } + }; + +} // end anonymous namespace. + +char PrintCallGraphPass::ID = 0; + +Pass *CallGraphSCCPass::createPrinterPass(raw_ostream &O, + const std::string &Banner) const { + return new PrintCallGraphPass(Banner, O); +} + Index: llvm/trunk/lib/Analysis/CallPrinter.cpp =================================================================== --- llvm/trunk/lib/Analysis/CallPrinter.cpp +++ llvm/trunk/lib/Analysis/CallPrinter.cpp @@ -0,0 +1,92 @@ +//===- CallPrinter.cpp - DOT printer for call graph -----------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file defines '-dot-callgraph', which emit a callgraph..dot +// containing the call graph of a module. +// +// There is also a pass available to directly call dotty ('-view-callgraph'). +// +//===----------------------------------------------------------------------===// + +#include "llvm/Analysis/CallGraph.h" +#include "llvm/Analysis/CallPrinter.h" +#include "llvm/Analysis/DOTGraphTraitsPass.h" + +using namespace llvm; + +namespace llvm { + +template <> struct DOTGraphTraits : public DefaultDOTGraphTraits { + DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {} + + static std::string getGraphName(CallGraph *Graph) { return "Call graph"; } + + std::string getNodeLabel(CallGraphNode *Node, CallGraph *Graph) { + if (Function *Func = Node->getFunction()) + return Func->getName(); + + return "external node"; + } +}; + +struct AnalysisCallGraphWrapperPassTraits { + static CallGraph *getGraph(CallGraphWrapperPass *P) { + return &P->getCallGraph(); + } +}; + +} // end llvm namespace + +namespace { + +struct CallGraphViewer + : public DOTGraphTraitsModuleViewer { + static char ID; + + CallGraphViewer() + : DOTGraphTraitsModuleViewer( + "callgraph", ID) { + initializeCallGraphViewerPass(*PassRegistry::getPassRegistry()); + } +}; + +struct CallGraphPrinter : public DOTGraphTraitsModulePrinter< + CallGraphWrapperPass, true, CallGraph *, + AnalysisCallGraphWrapperPassTraits> { + static char ID; + + CallGraphPrinter() + : DOTGraphTraitsModulePrinter( + "callgraph", ID) { + initializeCallGraphPrinterPass(*PassRegistry::getPassRegistry()); + } +}; + +} // end anonymous namespace + +char CallGraphViewer::ID = 0; +INITIALIZE_PASS(CallGraphViewer, "view-callgraph", "View call graph", false, + false) + +char CallGraphPrinter::ID = 0; +INITIALIZE_PASS(CallGraphPrinter, "dot-callgraph", + "Print call graph to 'dot' file", false, false) + +// Create methods available outside of this file, to use them +// "include/llvm/LinkAllPasses.h". Otherwise the pass would be deleted by +// the link time optimization. + +ModulePass *llvm::createCallGraphViewerPass() { return new CallGraphViewer(); } + +ModulePass *llvm::createCallGraphPrinterPass() { + return new CallGraphPrinter(); +} Index: llvm/trunk/lib/Analysis/GlobalsModRef.cpp =================================================================== --- llvm/trunk/lib/Analysis/GlobalsModRef.cpp +++ llvm/trunk/lib/Analysis/GlobalsModRef.cpp @@ -0,0 +1,798 @@ +//===- GlobalsModRef.cpp - Simple Mod/Ref Analysis for Globals ------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This simple pass provides alias and mod/ref information for global values +// that do not have their address taken, and keeps track of whether functions +// read or write memory (are "pure"). For this simple (but very common) case, +// we can provide pretty accurate and useful information. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Analysis/GlobalsModRef.h" +#include "llvm/ADT/SCCIterator.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/Analysis/MemoryBuiltins.h" +#include "llvm/Analysis/ValueTracking.h" +#include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/InstIterator.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/Module.h" +#include "llvm/Pass.h" +#include "llvm/Support/CommandLine.h" +using namespace llvm; + +#define DEBUG_TYPE "globalsmodref-aa" + +STATISTIC(NumNonAddrTakenGlobalVars, + "Number of global vars without address taken"); +STATISTIC(NumNonAddrTakenFunctions,"Number of functions without address taken"); +STATISTIC(NumNoMemFunctions, "Number of functions that do not access memory"); +STATISTIC(NumReadMemFunctions, "Number of functions that only read memory"); +STATISTIC(NumIndirectGlobalVars, "Number of indirect global objects"); + +// An option to enable unsafe alias results from the GlobalsModRef analysis. +// When enabled, GlobalsModRef will provide no-alias results which in extremely +// rare cases may not be conservatively correct. In particular, in the face of +// transforms which cause assymetry between how effective GetUnderlyingObject +// is for two pointers, it may produce incorrect results. +// +// These unsafe results have been returned by GMR for many years without +// causing significant issues in the wild and so we provide a mechanism to +// re-enable them for users of LLVM that have a particular performance +// sensitivity and no known issues. The option also makes it easy to evaluate +// the performance impact of these results. +static cl::opt EnableUnsafeGlobalsModRefAliasResults( + "enable-unsafe-globalsmodref-alias-results", cl::init(false), cl::Hidden); + +/// The mod/ref information collected for a particular function. +/// +/// We collect information about mod/ref behavior of a function here, both in +/// general and as pertains to specific globals. We only have this detailed +/// information when we know *something* useful about the behavior. If we +/// saturate to fully general mod/ref, we remove the info for the function. +class GlobalsModRef::FunctionInfo { + typedef SmallDenseMap GlobalInfoMapType; + + /// Build a wrapper struct that has 8-byte alignment. All heap allocations + /// should provide this much alignment at least, but this makes it clear we + /// specifically rely on this amount of alignment. + struct LLVM_ALIGNAS(8) AlignedMap { + AlignedMap() {} + AlignedMap(const AlignedMap &Arg) : Map(Arg.Map) {} + GlobalInfoMapType Map; + }; + + /// Pointer traits for our aligned map. + struct AlignedMapPointerTraits { + static inline void *getAsVoidPointer(AlignedMap *P) { return P; } + static inline AlignedMap *getFromVoidPointer(void *P) { + return (AlignedMap *)P; + } + enum { NumLowBitsAvailable = 3 }; + static_assert(AlignOf::Alignment >= (1 << NumLowBitsAvailable), + "AlignedMap insufficiently aligned to have enough low bits."); + }; + + /// The bit that flags that this function may read any global. This is + /// chosen to mix together with ModRefInfo bits. + enum { MayReadAnyGlobal = 4 }; + + /// Checks to document the invariants of the bit packing here. + static_assert((MayReadAnyGlobal & MRI_ModRef) == 0, + "ModRef and the MayReadAnyGlobal flag bits overlap."); + static_assert(((MayReadAnyGlobal | MRI_ModRef) >> + AlignedMapPointerTraits::NumLowBitsAvailable) == 0, + "Insufficient low bits to store our flag and ModRef info."); + +public: + FunctionInfo() : Info() {} + ~FunctionInfo() { + delete Info.getPointer(); + } + // Spell out the copy ond move constructors and assignment operators to get + // deep copy semantics and correct move semantics in the face of the + // pointer-int pair. + FunctionInfo(const FunctionInfo &Arg) + : Info(nullptr, Arg.Info.getInt()) { + if (const auto *ArgPtr = Arg.Info.getPointer()) + Info.setPointer(new AlignedMap(*ArgPtr)); + } + FunctionInfo(FunctionInfo &&Arg) + : Info(Arg.Info.getPointer(), Arg.Info.getInt()) { + Arg.Info.setPointerAndInt(nullptr, 0); + } + FunctionInfo &operator=(const FunctionInfo &RHS) { + delete Info.getPointer(); + Info.setPointerAndInt(nullptr, RHS.Info.getInt()); + if (const auto *RHSPtr = RHS.Info.getPointer()) + Info.setPointer(new AlignedMap(*RHSPtr)); + return *this; + } + FunctionInfo &operator=(FunctionInfo &&RHS) { + delete Info.getPointer(); + Info.setPointerAndInt(RHS.Info.getPointer(), RHS.Info.getInt()); + RHS.Info.setPointerAndInt(nullptr, 0); + return *this; + } + + /// Returns the \c ModRefInfo info for this function. + ModRefInfo getModRefInfo() const { + return ModRefInfo(Info.getInt() & MRI_ModRef); + } + + /// Adds new \c ModRefInfo for this function to its state. + void addModRefInfo(ModRefInfo NewMRI) { + Info.setInt(Info.getInt() | NewMRI); + } + + /// Returns whether this function may read any global variable, and we don't + /// know which global. + bool mayReadAnyGlobal() const { return Info.getInt() & MayReadAnyGlobal; } + + /// Sets this function as potentially reading from any global. + void setMayReadAnyGlobal() { Info.setInt(Info.getInt() | MayReadAnyGlobal); } + + /// Returns the \c ModRefInfo info for this function w.r.t. a particular + /// global, which may be more precise than the general information above. + ModRefInfo getModRefInfoForGlobal(const GlobalValue &GV) const { + ModRefInfo GlobalMRI = mayReadAnyGlobal() ? MRI_Ref : MRI_NoModRef; + if (AlignedMap *P = Info.getPointer()) { + auto I = P->Map.find(&GV); + if (I != P->Map.end()) + GlobalMRI = ModRefInfo(GlobalMRI | I->second); + } + return GlobalMRI; + } + + /// Add mod/ref info from another function into ours, saturating towards + /// MRI_ModRef. + void addFunctionInfo(const FunctionInfo &FI) { + addModRefInfo(FI.getModRefInfo()); + + if (FI.mayReadAnyGlobal()) + setMayReadAnyGlobal(); + + if (AlignedMap *P = FI.Info.getPointer()) + for (const auto &G : P->Map) + addModRefInfoForGlobal(*G.first, G.second); + } + + void addModRefInfoForGlobal(const GlobalValue &GV, ModRefInfo NewMRI) { + AlignedMap *P = Info.getPointer(); + if (!P) { + P = new AlignedMap(); + Info.setPointer(P); + } + auto &GlobalMRI = P->Map[&GV]; + GlobalMRI = ModRefInfo(GlobalMRI | NewMRI); + } + + /// Clear a global's ModRef info. Should be used when a global is being + /// deleted. + void eraseModRefInfoForGlobal(const GlobalValue &GV) { + if (AlignedMap *P = Info.getPointer()) + P->Map.erase(&GV); + } + +private: + /// All of the information is encoded into a single pointer, with a three bit + /// integer in the low three bits. The high bit provides a flag for when this + /// function may read any global. The low two bits are the ModRefInfo. And + /// the pointer, when non-null, points to a map from GlobalValue to + /// ModRefInfo specific to that GlobalValue. + PointerIntPair Info; +}; + +void GlobalsModRef::DeletionCallbackHandle::deleted() { + Value *V = getValPtr(); + if (auto *F = dyn_cast(V)) + GMR.FunctionInfos.erase(F); + + if (GlobalValue *GV = dyn_cast(V)) { + if (GMR.NonAddressTakenGlobals.erase(GV)) { + // This global might be an indirect global. If so, remove it and + // remove any AllocRelatedValues for it. + if (GMR.IndirectGlobals.erase(GV)) { + // Remove any entries in AllocsForIndirectGlobals for this global. + for (auto I = GMR.AllocsForIndirectGlobals.begin(), + E = GMR.AllocsForIndirectGlobals.end(); + I != E; ++I) + if (I->second == GV) + GMR.AllocsForIndirectGlobals.erase(I); + } + + // Scan the function info we have collected and remove this global + // from all of them. + for (auto &FIPair : GMR.FunctionInfos) + FIPair.second.eraseModRefInfoForGlobal(*GV); + } + } + + // If this is an allocation related to an indirect global, remove it. + GMR.AllocsForIndirectGlobals.erase(V); + + // And clear out the handle. + setValPtr(nullptr); + GMR.Handles.erase(I); + // This object is now destroyed! +} + +char GlobalsModRef::ID = 0; +INITIALIZE_AG_PASS_BEGIN(GlobalsModRef, AliasAnalysis, "globalsmodref-aa", + "Simple mod/ref analysis for globals", false, true, + false) +INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass) +INITIALIZE_AG_PASS_END(GlobalsModRef, AliasAnalysis, "globalsmodref-aa", + "Simple mod/ref analysis for globals", false, true, + false) + +Pass *llvm::createGlobalsModRefPass() { return new GlobalsModRef(); } + +GlobalsModRef::GlobalsModRef() : ModulePass(ID) { + initializeGlobalsModRefPass(*PassRegistry::getPassRegistry()); +} + +FunctionModRefBehavior GlobalsModRef::getModRefBehavior(const Function *F) { + FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior; + + if (FunctionInfo *FI = getFunctionInfo(F)) { + if (FI->getModRefInfo() == MRI_NoModRef) + Min = FMRB_DoesNotAccessMemory; + else if ((FI->getModRefInfo() & MRI_Mod) == 0) + Min = FMRB_OnlyReadsMemory; + } + + return FunctionModRefBehavior(AliasAnalysis::getModRefBehavior(F) & Min); +} + +FunctionModRefBehavior GlobalsModRef::getModRefBehavior(ImmutableCallSite CS) { + FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior; + + if (const Function *F = CS.getCalledFunction()) + if (FunctionInfo *FI = getFunctionInfo(F)) { + if (FI->getModRefInfo() == MRI_NoModRef) + Min = FMRB_DoesNotAccessMemory; + else if ((FI->getModRefInfo() & MRI_Mod) == 0) + Min = FMRB_OnlyReadsMemory; + } + + return FunctionModRefBehavior(AliasAnalysis::getModRefBehavior(CS) & Min); +} + +/// Returns the function info for the function, or null if we don't have +/// anything useful to say about it. +GlobalsModRef::FunctionInfo *GlobalsModRef::getFunctionInfo(const Function *F) { + auto I = FunctionInfos.find(F); + if (I != FunctionInfos.end()) + return &I->second; + return nullptr; +} + +/// AnalyzeGlobals - Scan through the users of all of the internal +/// GlobalValue's in the program. If none of them have their "address taken" +/// (really, their address passed to something nontrivial), record this fact, +/// and record the functions that they are used directly in. +void GlobalsModRef::AnalyzeGlobals(Module &M) { + SmallPtrSet TrackedFunctions; + for (Function &F : M) + if (F.hasLocalLinkage()) + if (!AnalyzeUsesOfPointer(&F)) { + // Remember that we are tracking this global. + NonAddressTakenGlobals.insert(&F); + TrackedFunctions.insert(&F); + Handles.emplace_front(*this, &F); + Handles.front().I = Handles.begin(); + ++NumNonAddrTakenFunctions; + } + + SmallPtrSet Readers, Writers; + for (GlobalVariable &GV : M.globals()) + if (GV.hasLocalLinkage()) { + if (!AnalyzeUsesOfPointer(&GV, &Readers, + GV.isConstant() ? nullptr : &Writers)) { + // Remember that we are tracking this global, and the mod/ref fns + NonAddressTakenGlobals.insert(&GV); + Handles.emplace_front(*this, &GV); + Handles.front().I = Handles.begin(); + + for (Function *Reader : Readers) { + if (TrackedFunctions.insert(Reader).second) { + Handles.emplace_front(*this, Reader); + Handles.front().I = Handles.begin(); + } + FunctionInfos[Reader].addModRefInfoForGlobal(GV, MRI_Ref); + } + + if (!GV.isConstant()) // No need to keep track of writers to constants + for (Function *Writer : Writers) { + if (TrackedFunctions.insert(Writer).second) { + Handles.emplace_front(*this, Writer); + Handles.front().I = Handles.begin(); + } + FunctionInfos[Writer].addModRefInfoForGlobal(GV, MRI_Mod); + } + ++NumNonAddrTakenGlobalVars; + + // If this global holds a pointer type, see if it is an indirect global. + if (GV.getType()->getElementType()->isPointerTy() && + AnalyzeIndirectGlobalMemory(&GV)) + ++NumIndirectGlobalVars; + } + Readers.clear(); + Writers.clear(); + } +} + +/// AnalyzeUsesOfPointer - Look at all of the users of the specified pointer. +/// If this is used by anything complex (i.e., the address escapes), return +/// true. Also, while we are at it, keep track of those functions that read and +/// write to the value. +/// +/// If OkayStoreDest is non-null, stores into this global are allowed. +bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V, + SmallPtrSetImpl *Readers, + SmallPtrSetImpl *Writers, + GlobalValue *OkayStoreDest) { + if (!V->getType()->isPointerTy()) + return true; + + for (Use &U : V->uses()) { + User *I = U.getUser(); + if (LoadInst *LI = dyn_cast(I)) { + if (Readers) + Readers->insert(LI->getParent()->getParent()); + } else if (StoreInst *SI = dyn_cast(I)) { + if (V == SI->getOperand(1)) { + if (Writers) + Writers->insert(SI->getParent()->getParent()); + } else if (SI->getOperand(1) != OkayStoreDest) { + return true; // Storing the pointer + } + } else if (Operator::getOpcode(I) == Instruction::GetElementPtr) { + if (AnalyzeUsesOfPointer(I, Readers, Writers)) + return true; + } else if (Operator::getOpcode(I) == Instruction::BitCast) { + if (AnalyzeUsesOfPointer(I, Readers, Writers, OkayStoreDest)) + return true; + } else if (auto CS = CallSite(I)) { + // Make sure that this is just the function being called, not that it is + // passing into the function. + if (!CS.isCallee(&U)) { + // Detect calls to free. + if (isFreeCall(I, TLI)) { + if (Writers) + Writers->insert(CS->getParent()->getParent()); + } else { + return true; // Argument of an unknown call. + } + } + } else if (ICmpInst *ICI = dyn_cast(I)) { + if (!isa(ICI->getOperand(1))) + return true; // Allow comparison against null. + } else { + return true; + } + } + + return false; +} + +/// AnalyzeIndirectGlobalMemory - We found an non-address-taken global variable +/// which holds a pointer type. See if the global always points to non-aliased +/// heap memory: that is, all initializers of the globals are allocations, and +/// those allocations have no use other than initialization of the global. +/// Further, all loads out of GV must directly use the memory, not store the +/// pointer somewhere. If this is true, we consider the memory pointed to by +/// GV to be owned by GV and can disambiguate other pointers from it. +bool GlobalsModRef::AnalyzeIndirectGlobalMemory(GlobalValue *GV) { + // Keep track of values related to the allocation of the memory, f.e. the + // value produced by the malloc call and any casts. + std::vector AllocRelatedValues; + + // Walk the user list of the global. If we find anything other than a direct + // load or store, bail out. + for (User *U : GV->users()) { + if (LoadInst *LI = dyn_cast(U)) { + // The pointer loaded from the global can only be used in simple ways: + // we allow addressing of it and loading storing to it. We do *not* allow + // storing the loaded pointer somewhere else or passing to a function. + if (AnalyzeUsesOfPointer(LI)) + return false; // Loaded pointer escapes. + // TODO: Could try some IP mod/ref of the loaded pointer. + } else if (StoreInst *SI = dyn_cast(U)) { + // Storing the global itself. + if (SI->getOperand(0) == GV) + return false; + + // If storing the null pointer, ignore it. + if (isa(SI->getOperand(0))) + continue; + + // Check the value being stored. + Value *Ptr = GetUnderlyingObject(SI->getOperand(0), + GV->getParent()->getDataLayout()); + + if (!isAllocLikeFn(Ptr, TLI)) + return false; // Too hard to analyze. + + // Analyze all uses of the allocation. If any of them are used in a + // non-simple way (e.g. stored to another global) bail out. + if (AnalyzeUsesOfPointer(Ptr, /*Readers*/ nullptr, /*Writers*/ nullptr, + GV)) + return false; // Loaded pointer escapes. + + // Remember that this allocation is related to the indirect global. + AllocRelatedValues.push_back(Ptr); + } else { + // Something complex, bail out. + return false; + } + } + + // Okay, this is an indirect global. Remember all of the allocations for + // this global in AllocsForIndirectGlobals. + while (!AllocRelatedValues.empty()) { + AllocsForIndirectGlobals[AllocRelatedValues.back()] = GV; + Handles.emplace_front(*this, AllocRelatedValues.back()); + Handles.front().I = Handles.begin(); + AllocRelatedValues.pop_back(); + } + IndirectGlobals.insert(GV); + Handles.emplace_front(*this, GV); + Handles.front().I = Handles.begin(); + return true; +} + +/// AnalyzeCallGraph - At this point, we know the functions where globals are +/// immediately stored to and read from. Propagate this information up the call +/// graph to all callers and compute the mod/ref info for all memory for each +/// function. +void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) { + // We do a bottom-up SCC traversal of the call graph. In other words, we + // visit all callees before callers (leaf-first). + for (scc_iterator I = scc_begin(&CG); !I.isAtEnd(); ++I) { + const std::vector &SCC = *I; + assert(!SCC.empty() && "SCC with no functions?"); + + if (!SCC[0]->getFunction()) { + // Calls externally - can't say anything useful. Remove any existing + // function records (may have been created when scanning globals). + for (auto *Node : SCC) + FunctionInfos.erase(Node->getFunction()); + continue; + } + + FunctionInfo &FI = FunctionInfos[SCC[0]->getFunction()]; + bool KnowNothing = false; + + // Collect the mod/ref properties due to called functions. We only compute + // one mod-ref set. + for (unsigned i = 0, e = SCC.size(); i != e && !KnowNothing; ++i) { + Function *F = SCC[i]->getFunction(); + if (!F) { + KnowNothing = true; + break; + } + + if (F->isDeclaration()) { + // Try to get mod/ref behaviour from function attributes. + if (F->doesNotAccessMemory()) { + // Can't do better than that! + } else if (F->onlyReadsMemory()) { + FI.addModRefInfo(MRI_Ref); + if (!F->isIntrinsic()) + // This function might call back into the module and read a global - + // consider every global as possibly being read by this function. + FI.setMayReadAnyGlobal(); + } else { + FI.addModRefInfo(MRI_ModRef); + // Can't say anything useful unless it's an intrinsic - they don't + // read or write global variables of the kind considered here. + KnowNothing = !F->isIntrinsic(); + } + continue; + } + + for (CallGraphNode::iterator CI = SCC[i]->begin(), E = SCC[i]->end(); + CI != E && !KnowNothing; ++CI) + if (Function *Callee = CI->second->getFunction()) { + if (FunctionInfo *CalleeFI = getFunctionInfo(Callee)) { + // Propagate function effect up. + FI.addFunctionInfo(*CalleeFI); + } else { + // Can't say anything about it. However, if it is inside our SCC, + // then nothing needs to be done. + CallGraphNode *CalleeNode = CG[Callee]; + if (std::find(SCC.begin(), SCC.end(), CalleeNode) == SCC.end()) + KnowNothing = true; + } + } else { + KnowNothing = true; + } + } + + // If we can't say anything useful about this SCC, remove all SCC functions + // from the FunctionInfos map. + if (KnowNothing) { + for (auto *Node : SCC) + FunctionInfos.erase(Node->getFunction()); + continue; + } + + // Scan the function bodies for explicit loads or stores. + for (auto *Node : SCC) { + if (FI.getModRefInfo() == MRI_ModRef) + break; // The mod/ref lattice saturates here. + for (Instruction &I : instructions(Node->getFunction())) { + if (FI.getModRefInfo() == MRI_ModRef) + break; // The mod/ref lattice saturates here. + + // We handle calls specially because the graph-relevant aspects are + // handled above. + if (auto CS = CallSite(&I)) { + if (isAllocationFn(&I, TLI) || isFreeCall(&I, TLI)) { + // FIXME: It is completely unclear why this is necessary and not + // handled by the above graph code. + FI.addModRefInfo(MRI_ModRef); + } else if (Function *Callee = CS.getCalledFunction()) { + // The callgraph doesn't include intrinsic calls. + if (Callee->isIntrinsic()) { + FunctionModRefBehavior Behaviour = + AliasAnalysis::getModRefBehavior(Callee); + FI.addModRefInfo(ModRefInfo(Behaviour & MRI_ModRef)); + } + } + continue; + } + + // All non-call instructions we use the primary predicates for whether + // thay read or write memory. + if (I.mayReadFromMemory()) + FI.addModRefInfo(MRI_Ref); + if (I.mayWriteToMemory()) + FI.addModRefInfo(MRI_Mod); + } + } + + if ((FI.getModRefInfo() & MRI_Mod) == 0) + ++NumReadMemFunctions; + if (FI.getModRefInfo() == MRI_NoModRef) + ++NumNoMemFunctions; + + // Finally, now that we know the full effect on this SCC, clone the + // information to each function in the SCC. + for (unsigned i = 1, e = SCC.size(); i != e; ++i) + FunctionInfos[SCC[i]->getFunction()] = FI; + } +} + +// There are particular cases where we can conclude no-alias between +// a non-addr-taken global and some other underlying object. Specifically, +// a non-addr-taken global is known to not be escaped from any function. It is +// also incorrect for a transformation to introduce an escape of a global in +// a way that is observable when it was not there previously. One function +// being transformed to introduce an escape which could possibly be observed +// (via loading from a global or the return value for example) within another +// function is never safe. If the observation is made through non-atomic +// operations on different threads, it is a data-race and UB. If the +// observation is well defined, by being observed the transformation would have +// changed program behavior by introducing the observed escape, making it an +// invalid transform. +// +// This property does require that transformations which *temporarily* escape +// a global that was not previously escaped, prior to restoring it, cannot rely +// on the results of GMR::alias. This seems a reasonable restriction, although +// currently there is no way to enforce it. There is also no realistic +// optimization pass that would make this mistake. The closest example is +// a transformation pass which does reg2mem of SSA values but stores them into +// global variables temporarily before restoring the global variable's value. +// This could be useful to expose "benign" races for example. However, it seems +// reasonable to require that a pass which introduces escapes of global +// variables in this way to either not trust AA results while the escape is +// active, or to be forced to operate as a module pass that cannot co-exist +// with an alias analysis such as GMR. +bool GlobalsModRef::isNonEscapingGlobalNoAlias(const GlobalValue *GV, + const Value *V) { + // In order to know that the underlying object cannot alias the + // non-addr-taken global, we must know that it would have to be an escape. + // Thus if the underlying object is a function argument, a load from + // a global, or the return of a function, it cannot alias. We can also + // recurse through PHI nodes and select nodes provided all of their inputs + // resolve to one of these known-escaping roots. + SmallPtrSet Visited; + SmallVector Inputs; + Visited.insert(V); + Inputs.push_back(V); + int Depth = 0; + do { + const Value *Input = Inputs.pop_back_val(); + + if (auto *InputGV = dyn_cast(Input)) { + // If one input is the very global we're querying against, then we can't + // conclude no-alias. + if (InputGV == GV) + return false; + + // Distinct GlobalVariables never alias, unless overriden or zero-sized. + // FIXME: The condition can be refined, but be conservative for now. + auto *GVar = dyn_cast(GV); + auto *InputGVar = dyn_cast(InputGV); + if (GVar && InputGVar && + !GVar->isDeclaration() && !InputGVar->isDeclaration() && + !GVar->mayBeOverridden() && !InputGVar->mayBeOverridden()) { + Type *GVType = GVar->getInitializer()->getType(); + Type *InputGVType = InputGVar->getInitializer()->getType(); + if (GVType->isSized() && InputGVType->isSized() && + (DL->getTypeAllocSize(GVType) > 0) && + (DL->getTypeAllocSize(InputGVType) > 0)) + continue; + } + + // Conservatively return false, even though we could be smarter + // (e.g. look through GlobalAliases). + return false; + } + + if (isa(Input) || isa(Input) || + isa(Input)) { + // Arguments to functions or returns from functions are inherently + // escaping, so we can immediately classify those as not aliasing any + // non-addr-taken globals. + continue; + } + if (auto *LI = dyn_cast(Input)) { + // A pointer loaded from a global would have been captured, and we know + // that the global is non-escaping, so no alias. + if (isa(GetUnderlyingObject(LI->getPointerOperand(), *DL))) + continue; + + // Otherwise, a load could come from anywhere, so bail. + return false; + } + + // Recurse through a limited number of selects and PHIs. This is an + // arbitrary depth of 4, lower numbers could be used to fix compile time + // issues if needed, but this is generally expected to be only be important + // for small depths. + if (++Depth > 4) + return false; + if (auto *SI = dyn_cast(Input)) { + const Value *LHS = GetUnderlyingObject(SI->getTrueValue(), *DL); + const Value *RHS = GetUnderlyingObject(SI->getFalseValue(), *DL); + if (Visited.insert(LHS).second) + Inputs.push_back(LHS); + if (Visited.insert(RHS).second) + Inputs.push_back(RHS); + continue; + } + if (auto *PN = dyn_cast(Input)) { + for (const Value *Op : PN->incoming_values()) { + Op = GetUnderlyingObject(Op, *DL); + if (Visited.insert(Op).second) + Inputs.push_back(Op); + } + continue; + } + + // FIXME: It would be good to handle other obvious no-alias cases here, but + // it isn't clear how to do so reasonbly without building a small version + // of BasicAA into this code. We could recurse into AliasAnalysis::alias + // here but that seems likely to go poorly as we're inside the + // implementation of such a query. Until then, just conservatievly retun + // false. + return false; + } while (!Inputs.empty()); + + // If all the inputs to V were definitively no-alias, then V is no-alias. + return true; +} + +/// alias - If one of the pointers is to a global that we are tracking, and the +/// other is some random pointer, we know there cannot be an alias, because the +/// address of the global isn't taken. +AliasResult GlobalsModRef::alias(const MemoryLocation &LocA, + const MemoryLocation &LocB) { + // Get the base object these pointers point to. + const Value *UV1 = GetUnderlyingObject(LocA.Ptr, *DL); + const Value *UV2 = GetUnderlyingObject(LocB.Ptr, *DL); + + // If either of the underlying values is a global, they may be non-addr-taken + // globals, which we can answer queries about. + const GlobalValue *GV1 = dyn_cast(UV1); + const GlobalValue *GV2 = dyn_cast(UV2); + if (GV1 || GV2) { + // If the global's address is taken, pretend we don't know it's a pointer to + // the global. + if (GV1 && !NonAddressTakenGlobals.count(GV1)) + GV1 = nullptr; + if (GV2 && !NonAddressTakenGlobals.count(GV2)) + GV2 = nullptr; + + // If the two pointers are derived from two different non-addr-taken + // globals we know these can't alias. + if (GV1 && GV2 && GV1 != GV2) + return NoAlias; + + // If one is and the other isn't, it isn't strictly safe but we can fake + // this result if necessary for performance. This does not appear to be + // a common problem in practice. + if (EnableUnsafeGlobalsModRefAliasResults) + if ((GV1 || GV2) && GV1 != GV2) + return NoAlias; + + // Check for a special case where a non-escaping global can be used to + // conclude no-alias. + if ((GV1 || GV2) && GV1 != GV2) { + const GlobalValue *GV = GV1 ? GV1 : GV2; + const Value *UV = GV1 ? UV2 : UV1; + if (isNonEscapingGlobalNoAlias(GV, UV)) + return NoAlias; + } + + // Otherwise if they are both derived from the same addr-taken global, we + // can't know the two accesses don't overlap. + } + + // These pointers may be based on the memory owned by an indirect global. If + // so, we may be able to handle this. First check to see if the base pointer + // is a direct load from an indirect global. + GV1 = GV2 = nullptr; + if (const LoadInst *LI = dyn_cast(UV1)) + if (GlobalVariable *GV = dyn_cast(LI->getOperand(0))) + if (IndirectGlobals.count(GV)) + GV1 = GV; + if (const LoadInst *LI = dyn_cast(UV2)) + if (const GlobalVariable *GV = dyn_cast(LI->getOperand(0))) + if (IndirectGlobals.count(GV)) + GV2 = GV; + + // These pointers may also be from an allocation for the indirect global. If + // so, also handle them. + if (!GV1) + GV1 = AllocsForIndirectGlobals.lookup(UV1); + if (!GV2) + GV2 = AllocsForIndirectGlobals.lookup(UV2); + + // Now that we know whether the two pointers are related to indirect globals, + // use this to disambiguate the pointers. If the pointers are based on + // different indirect globals they cannot alias. + if (GV1 && GV2 && GV1 != GV2) + return NoAlias; + + // If one is based on an indirect global and the other isn't, it isn't + // strictly safe but we can fake this result if necessary for performance. + // This does not appear to be a common problem in practice. + if (EnableUnsafeGlobalsModRefAliasResults) + if ((GV1 || GV2) && GV1 != GV2) + return NoAlias; + + return AliasAnalysis::alias(LocA, LocB); +} + +ModRefInfo GlobalsModRef::getModRefInfo(ImmutableCallSite CS, + const MemoryLocation &Loc) { + unsigned Known = MRI_ModRef; + + // If we are asking for mod/ref info of a direct call with a pointer to a + // global we are tracking, return information if we have it. + const DataLayout &DL = CS.getCaller()->getParent()->getDataLayout(); + if (const GlobalValue *GV = + dyn_cast(GetUnderlyingObject(Loc.Ptr, DL))) + if (GV->hasLocalLinkage()) + if (const Function *F = CS.getCalledFunction()) + if (NonAddressTakenGlobals.count(GV)) + if (const FunctionInfo *FI = getFunctionInfo(F)) + Known = FI->getModRefInfoForGlobal(*GV); + + if (Known == MRI_NoModRef) + return MRI_NoModRef; // No need to query other mod/ref analyses + return ModRefInfo(Known & AliasAnalysis::getModRefInfo(CS, Loc)); +} Index: llvm/trunk/lib/Analysis/IPA/CMakeLists.txt =================================================================== --- llvm/trunk/lib/Analysis/IPA/CMakeLists.txt +++ llvm/trunk/lib/Analysis/IPA/CMakeLists.txt @@ -1,10 +0,0 @@ -add_llvm_library(LLVMipa - CallGraph.cpp - CallGraphSCCPass.cpp - CallPrinter.cpp - GlobalsModRef.cpp - IPA.cpp - InlineCost.cpp - ) - -add_dependencies(LLVMipa intrinsics_gen) Index: llvm/trunk/lib/Analysis/IPA/CallGraph.cpp =================================================================== --- llvm/trunk/lib/Analysis/IPA/CallGraph.cpp +++ llvm/trunk/lib/Analysis/IPA/CallGraph.cpp @@ -1,309 +0,0 @@ -//===- CallGraph.cpp - Build a Module's call graph ------------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Analysis/CallGraph.h" -#include "llvm/IR/CallSite.h" -#include "llvm/IR/Instructions.h" -#include "llvm/IR/IntrinsicInst.h" -#include "llvm/IR/Module.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/raw_ostream.h" -using namespace llvm; - -//===----------------------------------------------------------------------===// -// Implementations of the CallGraph class methods. -// - -CallGraph::CallGraph(Module &M) - : M(M), Root(nullptr), ExternalCallingNode(getOrInsertFunction(nullptr)), - CallsExternalNode(llvm::make_unique(nullptr)) { - // Add every function to the call graph. - for (Function &F : M) - addToCallGraph(&F); - - // If we didn't find a main function, use the external call graph node - if (!Root) - Root = ExternalCallingNode; -} - -CallGraph::CallGraph(CallGraph &&Arg) - : M(Arg.M), FunctionMap(std::move(Arg.FunctionMap)), Root(Arg.Root), - ExternalCallingNode(Arg.ExternalCallingNode), - CallsExternalNode(std::move(Arg.CallsExternalNode)) { - Arg.FunctionMap.clear(); - Arg.Root = nullptr; - Arg.ExternalCallingNode = nullptr; -} - -CallGraph::~CallGraph() { - // CallsExternalNode is not in the function map, delete it explicitly. - if (CallsExternalNode) - CallsExternalNode->allReferencesDropped(); - -// Reset all node's use counts to zero before deleting them to prevent an -// assertion from firing. -#ifndef NDEBUG - for (auto &I : FunctionMap) - I.second->allReferencesDropped(); -#endif -} - -void CallGraph::addToCallGraph(Function *F) { - CallGraphNode *Node = getOrInsertFunction(F); - - // If this function has external linkage, anything could call it. - if (!F->hasLocalLinkage()) { - ExternalCallingNode->addCalledFunction(CallSite(), Node); - - // Found the entry point? - if (F->getName() == "main") { - if (Root) // Found multiple external mains? Don't pick one. - Root = ExternalCallingNode; - else - Root = Node; // Found a main, keep track of it! - } - } - - // If this function has its address taken, anything could call it. - if (F->hasAddressTaken()) - ExternalCallingNode->addCalledFunction(CallSite(), Node); - - // If this function is not defined in this translation unit, it could call - // anything. - if (F->isDeclaration() && !F->isIntrinsic()) - Node->addCalledFunction(CallSite(), CallsExternalNode.get()); - - // Look for calls by this function. - for (Function::iterator BB = F->begin(), BBE = F->end(); BB != BBE; ++BB) - for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE; - ++II) { - CallSite CS(cast(II)); - if (CS) { - const Function *Callee = CS.getCalledFunction(); - if (!Callee || !Intrinsic::isLeaf(Callee->getIntrinsicID())) - // Indirect calls of intrinsics are not allowed so no need to check. - // We can be more precise here by using TargetArg returned by - // Intrinsic::isLeaf. - Node->addCalledFunction(CS, CallsExternalNode.get()); - else if (!Callee->isIntrinsic()) - Node->addCalledFunction(CS, getOrInsertFunction(Callee)); - } - } -} - -void CallGraph::print(raw_ostream &OS) const { - OS << "CallGraph Root is: "; - if (Function *F = Root->getFunction()) - OS << F->getName() << "\n"; - else { - OS << "<>\n"; - } - - // Print in a deterministic order by sorting CallGraphNodes by name. We do - // this here to avoid slowing down the non-printing fast path. - - SmallVector Nodes; - Nodes.reserve(FunctionMap.size()); - - for (auto I = begin(), E = end(); I != E; ++I) - Nodes.push_back(I->second.get()); - - std::sort(Nodes.begin(), Nodes.end(), - [](CallGraphNode *LHS, CallGraphNode *RHS) { - if (Function *LF = LHS->getFunction()) - if (Function *RF = RHS->getFunction()) - return LF->getName() < RF->getName(); - - return RHS->getFunction() != nullptr; - }); - - for (CallGraphNode *CN : Nodes) - CN->print(OS); -} - -#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) -void CallGraph::dump() const { print(dbgs()); } -#endif - -// removeFunctionFromModule - Unlink the function from this module, returning -// it. Because this removes the function from the module, the call graph node -// is destroyed. This is only valid if the function does not call any other -// functions (ie, there are no edges in it's CGN). The easiest way to do this -// is to dropAllReferences before calling this. -// -Function *CallGraph::removeFunctionFromModule(CallGraphNode *CGN) { - assert(CGN->empty() && "Cannot remove function from call " - "graph if it references other functions!"); - Function *F = CGN->getFunction(); // Get the function for the call graph node - FunctionMap.erase(F); // Remove the call graph node from the map - - M.getFunctionList().remove(F); - return F; -} - -/// spliceFunction - Replace the function represented by this node by another. -/// This does not rescan the body of the function, so it is suitable when -/// splicing the body of the old function to the new while also updating all -/// callers from old to new. -/// -void CallGraph::spliceFunction(const Function *From, const Function *To) { - assert(FunctionMap.count(From) && "No CallGraphNode for function!"); - assert(!FunctionMap.count(To) && - "Pointing CallGraphNode at a function that already exists"); - FunctionMapTy::iterator I = FunctionMap.find(From); - I->second->F = const_cast(To); - FunctionMap[To] = std::move(I->second); - FunctionMap.erase(I); -} - -// getOrInsertFunction - This method is identical to calling operator[], but -// it will insert a new CallGraphNode for the specified function if one does -// not already exist. -CallGraphNode *CallGraph::getOrInsertFunction(const Function *F) { - auto &CGN = FunctionMap[F]; - if (CGN) - return CGN.get(); - - assert((!F || F->getParent() == &M) && "Function not in current module!"); - CGN = llvm::make_unique(const_cast(F)); - return CGN.get(); -} - -//===----------------------------------------------------------------------===// -// Implementations of the CallGraphNode class methods. -// - -void CallGraphNode::print(raw_ostream &OS) const { - if (Function *F = getFunction()) - OS << "Call graph node for function: '" << F->getName() << "'"; - else - OS << "Call graph node <>"; - - OS << "<<" << this << ">> #uses=" << getNumReferences() << '\n'; - - for (const_iterator I = begin(), E = end(); I != E; ++I) { - OS << " CS<" << I->first << "> calls "; - if (Function *FI = I->second->getFunction()) - OS << "function '" << FI->getName() <<"'\n"; - else - OS << "external node\n"; - } - OS << '\n'; -} - -#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) -void CallGraphNode::dump() const { print(dbgs()); } -#endif - -/// removeCallEdgeFor - This method removes the edge in the node for the -/// specified call site. Note that this method takes linear time, so it -/// should be used sparingly. -void CallGraphNode::removeCallEdgeFor(CallSite CS) { - for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) { - assert(I != CalledFunctions.end() && "Cannot find callsite to remove!"); - if (I->first == CS.getInstruction()) { - I->second->DropRef(); - *I = CalledFunctions.back(); - CalledFunctions.pop_back(); - return; - } - } -} - -// removeAnyCallEdgeTo - This method removes any call edges from this node to -// the specified callee function. This takes more time to execute than -// removeCallEdgeTo, so it should not be used unless necessary. -void CallGraphNode::removeAnyCallEdgeTo(CallGraphNode *Callee) { - for (unsigned i = 0, e = CalledFunctions.size(); i != e; ++i) - if (CalledFunctions[i].second == Callee) { - Callee->DropRef(); - CalledFunctions[i] = CalledFunctions.back(); - CalledFunctions.pop_back(); - --i; --e; - } -} - -/// removeOneAbstractEdgeTo - Remove one edge associated with a null callsite -/// from this node to the specified callee function. -void CallGraphNode::removeOneAbstractEdgeTo(CallGraphNode *Callee) { - for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) { - assert(I != CalledFunctions.end() && "Cannot find callee to remove!"); - CallRecord &CR = *I; - if (CR.second == Callee && CR.first == nullptr) { - Callee->DropRef(); - *I = CalledFunctions.back(); - CalledFunctions.pop_back(); - return; - } - } -} - -/// replaceCallEdge - This method replaces the edge in the node for the -/// specified call site with a new one. Note that this method takes linear -/// time, so it should be used sparingly. -void CallGraphNode::replaceCallEdge(CallSite CS, - CallSite NewCS, CallGraphNode *NewNode){ - for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) { - assert(I != CalledFunctions.end() && "Cannot find callsite to remove!"); - if (I->first == CS.getInstruction()) { - I->second->DropRef(); - I->first = NewCS.getInstruction(); - I->second = NewNode; - NewNode->AddRef(); - return; - } - } -} - -//===----------------------------------------------------------------------===// -// Out-of-line definitions of CallGraphAnalysis class members. -// - -char CallGraphAnalysis::PassID; - -//===----------------------------------------------------------------------===// -// Implementations of the CallGraphWrapperPass class methods. -// - -CallGraphWrapperPass::CallGraphWrapperPass() : ModulePass(ID) { - initializeCallGraphWrapperPassPass(*PassRegistry::getPassRegistry()); -} - -CallGraphWrapperPass::~CallGraphWrapperPass() {} - -void CallGraphWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { - AU.setPreservesAll(); -} - -bool CallGraphWrapperPass::runOnModule(Module &M) { - // All the real work is done in the constructor for the CallGraph. - G.reset(new CallGraph(M)); - return false; -} - -INITIALIZE_PASS(CallGraphWrapperPass, "basiccg", "CallGraph Construction", - false, true) - -char CallGraphWrapperPass::ID = 0; - -void CallGraphWrapperPass::releaseMemory() { G.reset(); } - -void CallGraphWrapperPass::print(raw_ostream &OS, const Module *) const { - if (!G) { - OS << "No call graph has been built!\n"; - return; - } - - // Just delegate. - G->print(OS); -} - -#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) -void CallGraphWrapperPass::dump() const { print(dbgs(), nullptr); } -#endif Index: llvm/trunk/lib/Analysis/IPA/CallGraphSCCPass.cpp =================================================================== --- llvm/trunk/lib/Analysis/IPA/CallGraphSCCPass.cpp +++ llvm/trunk/lib/Analysis/IPA/CallGraphSCCPass.cpp @@ -1,632 +0,0 @@ -//===- CallGraphSCCPass.cpp - Pass that operates BU on call graph ---------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements the CallGraphSCCPass class, which is used for passes -// which are implemented as bottom-up traversals on the call graph. Because -// there may be cycles in the call graph, passes of this type operate on the -// call-graph in SCC order: that is, they process function bottom-up, except for -// recursive functions, which they process all at once. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Analysis/CallGraphSCCPass.h" -#include "llvm/ADT/SCCIterator.h" -#include "llvm/ADT/Statistic.h" -#include "llvm/Analysis/CallGraph.h" -#include "llvm/IR/Function.h" -#include "llvm/IR/IntrinsicInst.h" -#include "llvm/IR/LLVMContext.h" -#include "llvm/IR/LegacyPassManagers.h" -#include "llvm/Support/CommandLine.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/Timer.h" -#include "llvm/Support/raw_ostream.h" -using namespace llvm; - -#define DEBUG_TYPE "cgscc-passmgr" - -static cl::opt -MaxIterations("max-cg-scc-iterations", cl::ReallyHidden, cl::init(4)); - -STATISTIC(MaxSCCIterations, "Maximum CGSCCPassMgr iterations on one SCC"); - -//===----------------------------------------------------------------------===// -// CGPassManager -// -/// CGPassManager manages FPPassManagers and CallGraphSCCPasses. - -namespace { - -class CGPassManager : public ModulePass, public PMDataManager { -public: - static char ID; - explicit CGPassManager() - : ModulePass(ID), PMDataManager() { } - - /// Execute all of the passes scheduled for execution. Keep track of - /// whether any of the passes modifies the module, and if so, return true. - bool runOnModule(Module &M) override; - - using ModulePass::doInitialization; - using ModulePass::doFinalization; - - bool doInitialization(CallGraph &CG); - bool doFinalization(CallGraph &CG); - - /// Pass Manager itself does not invalidate any analysis info. - void getAnalysisUsage(AnalysisUsage &Info) const override { - // CGPassManager walks SCC and it needs CallGraph. - Info.addRequired(); - Info.setPreservesAll(); - } - - const char *getPassName() const override { - return "CallGraph Pass Manager"; - } - - PMDataManager *getAsPMDataManager() override { return this; } - Pass *getAsPass() override { return this; } - - // Print passes managed by this manager - void dumpPassStructure(unsigned Offset) override { - errs().indent(Offset*2) << "Call Graph SCC Pass Manager\n"; - for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) { - Pass *P = getContainedPass(Index); - P->dumpPassStructure(Offset + 1); - dumpLastUses(P, Offset+1); - } - } - - Pass *getContainedPass(unsigned N) { - assert(N < PassVector.size() && "Pass number out of range!"); - return static_cast(PassVector[N]); - } - - PassManagerType getPassManagerType() const override { - return PMT_CallGraphPassManager; - } - -private: - bool RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG, - bool &DevirtualizedCall); - - bool RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC, - CallGraph &CG, bool &CallGraphUpToDate, - bool &DevirtualizedCall); - bool RefreshCallGraph(CallGraphSCC &CurSCC, CallGraph &CG, - bool IsCheckingMode); -}; - -} // end anonymous namespace. - -char CGPassManager::ID = 0; - - -bool CGPassManager::RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC, - CallGraph &CG, bool &CallGraphUpToDate, - bool &DevirtualizedCall) { - bool Changed = false; - PMDataManager *PM = P->getAsPMDataManager(); - - if (!PM) { - CallGraphSCCPass *CGSP = (CallGraphSCCPass*)P; - if (!CallGraphUpToDate) { - DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, false); - CallGraphUpToDate = true; - } - - { - TimeRegion PassTimer(getPassTimer(CGSP)); - Changed = CGSP->runOnSCC(CurSCC); - } - - // After the CGSCCPass is done, when assertions are enabled, use - // RefreshCallGraph to verify that the callgraph was correctly updated. -#ifndef NDEBUG - if (Changed) - RefreshCallGraph(CurSCC, CG, true); -#endif - - return Changed; - } - - - assert(PM->getPassManagerType() == PMT_FunctionPassManager && - "Invalid CGPassManager member"); - FPPassManager *FPP = (FPPassManager*)P; - - // Run pass P on all functions in the current SCC. - for (CallGraphNode *CGN : CurSCC) { - if (Function *F = CGN->getFunction()) { - dumpPassInfo(P, EXECUTION_MSG, ON_FUNCTION_MSG, F->getName()); - { - TimeRegion PassTimer(getPassTimer(FPP)); - Changed |= FPP->runOnFunction(*F); - } - F->getContext().yield(); - } - } - - // The function pass(es) modified the IR, they may have clobbered the - // callgraph. - if (Changed && CallGraphUpToDate) { - DEBUG(dbgs() << "CGSCCPASSMGR: Pass Dirtied SCC: " - << P->getPassName() << '\n'); - CallGraphUpToDate = false; - } - return Changed; -} - - -/// Scan the functions in the specified CFG and resync the -/// callgraph with the call sites found in it. This is used after -/// FunctionPasses have potentially munged the callgraph, and can be used after -/// CallGraphSCC passes to verify that they correctly updated the callgraph. -/// -/// This function returns true if it devirtualized an existing function call, -/// meaning it turned an indirect call into a direct call. This happens when -/// a function pass like GVN optimizes away stuff feeding the indirect call. -/// This never happens in checking mode. -/// -bool CGPassManager::RefreshCallGraph(CallGraphSCC &CurSCC, - CallGraph &CG, bool CheckingMode) { - DenseMap CallSites; - - DEBUG(dbgs() << "CGSCCPASSMGR: Refreshing SCC with " << CurSCC.size() - << " nodes:\n"; - for (CallGraphNode *CGN : CurSCC) - CGN->dump(); - ); - - bool MadeChange = false; - bool DevirtualizedCall = false; - - // Scan all functions in the SCC. - unsigned FunctionNo = 0; - for (CallGraphSCC::iterator SCCIdx = CurSCC.begin(), E = CurSCC.end(); - SCCIdx != E; ++SCCIdx, ++FunctionNo) { - CallGraphNode *CGN = *SCCIdx; - Function *F = CGN->getFunction(); - if (!F || F->isDeclaration()) continue; - - // Walk the function body looking for call sites. Sync up the call sites in - // CGN with those actually in the function. - - // Keep track of the number of direct and indirect calls that were - // invalidated and removed. - unsigned NumDirectRemoved = 0, NumIndirectRemoved = 0; - - // Get the set of call sites currently in the function. - for (CallGraphNode::iterator I = CGN->begin(), E = CGN->end(); I != E; ) { - // If this call site is null, then the function pass deleted the call - // entirely and the WeakVH nulled it out. - if (!I->first || - // If we've already seen this call site, then the FunctionPass RAUW'd - // one call with another, which resulted in two "uses" in the edge - // list of the same call. - CallSites.count(I->first) || - - // If the call edge is not from a call or invoke, or it is a - // instrinsic call, then the function pass RAUW'd a call with - // another value. This can happen when constant folding happens - // of well known functions etc. - !CallSite(I->first) || - (CallSite(I->first).getCalledFunction() && - CallSite(I->first).getCalledFunction()->isIntrinsic() && - Intrinsic::isLeaf( - CallSite(I->first).getCalledFunction()->getIntrinsicID()))) { - assert(!CheckingMode && - "CallGraphSCCPass did not update the CallGraph correctly!"); - - // If this was an indirect call site, count it. - if (!I->second->getFunction()) - ++NumIndirectRemoved; - else - ++NumDirectRemoved; - - // Just remove the edge from the set of callees, keep track of whether - // I points to the last element of the vector. - bool WasLast = I + 1 == E; - CGN->removeCallEdge(I); - - // If I pointed to the last element of the vector, we have to bail out: - // iterator checking rejects comparisons of the resultant pointer with - // end. - if (WasLast) - break; - E = CGN->end(); - continue; - } - - assert(!CallSites.count(I->first) && - "Call site occurs in node multiple times"); - - CallSite CS(I->first); - if (CS) { - Function *Callee = CS.getCalledFunction(); - // Ignore intrinsics because they're not really function calls. - if (!Callee || !(Callee->isIntrinsic())) - CallSites.insert(std::make_pair(I->first, I->second)); - } - ++I; - } - - // Loop over all of the instructions in the function, getting the callsites. - // Keep track of the number of direct/indirect calls added. - unsigned NumDirectAdded = 0, NumIndirectAdded = 0; - - for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) - for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { - CallSite CS(cast(I)); - if (!CS) continue; - Function *Callee = CS.getCalledFunction(); - if (Callee && Callee->isIntrinsic()) continue; - - // If this call site already existed in the callgraph, just verify it - // matches up to expectations and remove it from CallSites. - DenseMap::iterator ExistingIt = - CallSites.find(CS.getInstruction()); - if (ExistingIt != CallSites.end()) { - CallGraphNode *ExistingNode = ExistingIt->second; - - // Remove from CallSites since we have now seen it. - CallSites.erase(ExistingIt); - - // Verify that the callee is right. - if (ExistingNode->getFunction() == CS.getCalledFunction()) - continue; - - // If we are in checking mode, we are not allowed to actually mutate - // the callgraph. If this is a case where we can infer that the - // callgraph is less precise than it could be (e.g. an indirect call - // site could be turned direct), don't reject it in checking mode, and - // don't tweak it to be more precise. - if (CheckingMode && CS.getCalledFunction() && - ExistingNode->getFunction() == nullptr) - continue; - - assert(!CheckingMode && - "CallGraphSCCPass did not update the CallGraph correctly!"); - - // If not, we either went from a direct call to indirect, indirect to - // direct, or direct to different direct. - CallGraphNode *CalleeNode; - if (Function *Callee = CS.getCalledFunction()) { - CalleeNode = CG.getOrInsertFunction(Callee); - // Keep track of whether we turned an indirect call into a direct - // one. - if (!ExistingNode->getFunction()) { - DevirtualizedCall = true; - DEBUG(dbgs() << " CGSCCPASSMGR: Devirtualized call to '" - << Callee->getName() << "'\n"); - } - } else { - CalleeNode = CG.getCallsExternalNode(); - } - - // Update the edge target in CGN. - CGN->replaceCallEdge(CS, CS, CalleeNode); - MadeChange = true; - continue; - } - - assert(!CheckingMode && - "CallGraphSCCPass did not update the CallGraph correctly!"); - - // If the call site didn't exist in the CGN yet, add it. - CallGraphNode *CalleeNode; - if (Function *Callee = CS.getCalledFunction()) { - CalleeNode = CG.getOrInsertFunction(Callee); - ++NumDirectAdded; - } else { - CalleeNode = CG.getCallsExternalNode(); - ++NumIndirectAdded; - } - - CGN->addCalledFunction(CS, CalleeNode); - MadeChange = true; - } - - // We scanned the old callgraph node, removing invalidated call sites and - // then added back newly found call sites. One thing that can happen is - // that an old indirect call site was deleted and replaced with a new direct - // call. In this case, we have devirtualized a call, and CGSCCPM would like - // to iteratively optimize the new code. Unfortunately, we don't really - // have a great way to detect when this happens. As an approximation, we - // just look at whether the number of indirect calls is reduced and the - // number of direct calls is increased. There are tons of ways to fool this - // (e.g. DCE'ing an indirect call and duplicating an unrelated block with a - // direct call) but this is close enough. - if (NumIndirectRemoved > NumIndirectAdded && - NumDirectRemoved < NumDirectAdded) - DevirtualizedCall = true; - - // After scanning this function, if we still have entries in callsites, then - // they are dangling pointers. WeakVH should save us for this, so abort if - // this happens. - assert(CallSites.empty() && "Dangling pointers found in call sites map"); - - // Periodically do an explicit clear to remove tombstones when processing - // large scc's. - if ((FunctionNo & 15) == 15) - CallSites.clear(); - } - - DEBUG(if (MadeChange) { - dbgs() << "CGSCCPASSMGR: Refreshed SCC is now:\n"; - for (CallGraphNode *CGN : CurSCC) - CGN->dump(); - if (DevirtualizedCall) - dbgs() << "CGSCCPASSMGR: Refresh devirtualized a call!\n"; - - } else { - dbgs() << "CGSCCPASSMGR: SCC Refresh didn't change call graph.\n"; - } - ); - (void)MadeChange; - - return DevirtualizedCall; -} - -/// Execute the body of the entire pass manager on the specified SCC. -/// This keeps track of whether a function pass devirtualizes -/// any calls and returns it in DevirtualizedCall. -bool CGPassManager::RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG, - bool &DevirtualizedCall) { - bool Changed = false; - - // Keep track of whether the callgraph is known to be up-to-date or not. - // The CGSSC pass manager runs two types of passes: - // CallGraphSCC Passes and other random function passes. Because other - // random function passes are not CallGraph aware, they may clobber the - // call graph by introducing new calls or deleting other ones. This flag - // is set to false when we run a function pass so that we know to clean up - // the callgraph when we need to run a CGSCCPass again. - bool CallGraphUpToDate = true; - - // Run all passes on current SCC. - for (unsigned PassNo = 0, e = getNumContainedPasses(); - PassNo != e; ++PassNo) { - Pass *P = getContainedPass(PassNo); - - // If we're in -debug-pass=Executions mode, construct the SCC node list, - // otherwise avoid constructing this string as it is expensive. - if (isPassDebuggingExecutionsOrMore()) { - std::string Functions; - #ifndef NDEBUG - raw_string_ostream OS(Functions); - for (CallGraphSCC::iterator I = CurSCC.begin(), E = CurSCC.end(); - I != E; ++I) { - if (I != CurSCC.begin()) OS << ", "; - (*I)->print(OS); - } - OS.flush(); - #endif - dumpPassInfo(P, EXECUTION_MSG, ON_CG_MSG, Functions); - } - dumpRequiredSet(P); - - initializeAnalysisImpl(P); - - // Actually run this pass on the current SCC. - Changed |= RunPassOnSCC(P, CurSCC, CG, - CallGraphUpToDate, DevirtualizedCall); - - if (Changed) - dumpPassInfo(P, MODIFICATION_MSG, ON_CG_MSG, ""); - dumpPreservedSet(P); - - verifyPreservedAnalysis(P); - removeNotPreservedAnalysis(P); - recordAvailableAnalysis(P); - removeDeadPasses(P, "", ON_CG_MSG); - } - - // If the callgraph was left out of date (because the last pass run was a - // functionpass), refresh it before we move on to the next SCC. - if (!CallGraphUpToDate) - DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, false); - return Changed; -} - -/// Execute all of the passes scheduled for execution. Keep track of -/// whether any of the passes modifies the module, and if so, return true. -bool CGPassManager::runOnModule(Module &M) { - CallGraph &CG = getAnalysis().getCallGraph(); - bool Changed = doInitialization(CG); - - // Walk the callgraph in bottom-up SCC order. - scc_iterator CGI = scc_begin(&CG); - - CallGraphSCC CurSCC(&CGI); - while (!CGI.isAtEnd()) { - // Copy the current SCC and increment past it so that the pass can hack - // on the SCC if it wants to without invalidating our iterator. - const std::vector &NodeVec = *CGI; - CurSCC.initialize(NodeVec.data(), NodeVec.data() + NodeVec.size()); - ++CGI; - - // At the top level, we run all the passes in this pass manager on the - // functions in this SCC. However, we support iterative compilation in the - // case where a function pass devirtualizes a call to a function. For - // example, it is very common for a function pass (often GVN or instcombine) - // to eliminate the addressing that feeds into a call. With that improved - // information, we would like the call to be an inline candidate, infer - // mod-ref information etc. - // - // Because of this, we allow iteration up to a specified iteration count. - // This only happens in the case of a devirtualized call, so we only burn - // compile time in the case that we're making progress. We also have a hard - // iteration count limit in case there is crazy code. - unsigned Iteration = 0; - bool DevirtualizedCall = false; - do { - DEBUG(if (Iteration) - dbgs() << " SCCPASSMGR: Re-visiting SCC, iteration #" - << Iteration << '\n'); - DevirtualizedCall = false; - Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall); - } while (Iteration++ < MaxIterations && DevirtualizedCall); - - if (DevirtualizedCall) - DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after " << Iteration - << " times, due to -max-cg-scc-iterations\n"); - - if (Iteration > MaxSCCIterations) - MaxSCCIterations = Iteration; - - } - Changed |= doFinalization(CG); - return Changed; -} - - -/// Initialize CG -bool CGPassManager::doInitialization(CallGraph &CG) { - bool Changed = false; - for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) { - if (PMDataManager *PM = getContainedPass(i)->getAsPMDataManager()) { - assert(PM->getPassManagerType() == PMT_FunctionPassManager && - "Invalid CGPassManager member"); - Changed |= ((FPPassManager*)PM)->doInitialization(CG.getModule()); - } else { - Changed |= ((CallGraphSCCPass*)getContainedPass(i))->doInitialization(CG); - } - } - return Changed; -} - -/// Finalize CG -bool CGPassManager::doFinalization(CallGraph &CG) { - bool Changed = false; - for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) { - if (PMDataManager *PM = getContainedPass(i)->getAsPMDataManager()) { - assert(PM->getPassManagerType() == PMT_FunctionPassManager && - "Invalid CGPassManager member"); - Changed |= ((FPPassManager*)PM)->doFinalization(CG.getModule()); - } else { - Changed |= ((CallGraphSCCPass*)getContainedPass(i))->doFinalization(CG); - } - } - return Changed; -} - -//===----------------------------------------------------------------------===// -// CallGraphSCC Implementation -//===----------------------------------------------------------------------===// - -/// This informs the SCC and the pass manager that the specified -/// Old node has been deleted, and New is to be used in its place. -void CallGraphSCC::ReplaceNode(CallGraphNode *Old, CallGraphNode *New) { - assert(Old != New && "Should not replace node with self"); - for (unsigned i = 0; ; ++i) { - assert(i != Nodes.size() && "Node not in SCC"); - if (Nodes[i] != Old) continue; - Nodes[i] = New; - break; - } - - // Update the active scc_iterator so that it doesn't contain dangling - // pointers to the old CallGraphNode. - scc_iterator *CGI = (scc_iterator*)Context; - CGI->ReplaceNode(Old, New); -} - - -//===----------------------------------------------------------------------===// -// CallGraphSCCPass Implementation -//===----------------------------------------------------------------------===// - -/// Assign pass manager to manage this pass. -void CallGraphSCCPass::assignPassManager(PMStack &PMS, - PassManagerType PreferredType) { - // Find CGPassManager - while (!PMS.empty() && - PMS.top()->getPassManagerType() > PMT_CallGraphPassManager) - PMS.pop(); - - assert(!PMS.empty() && "Unable to handle Call Graph Pass"); - CGPassManager *CGP; - - if (PMS.top()->getPassManagerType() == PMT_CallGraphPassManager) - CGP = (CGPassManager*)PMS.top(); - else { - // Create new Call Graph SCC Pass Manager if it does not exist. - assert(!PMS.empty() && "Unable to create Call Graph Pass Manager"); - PMDataManager *PMD = PMS.top(); - - // [1] Create new Call Graph Pass Manager - CGP = new CGPassManager(); - - // [2] Set up new manager's top level manager - PMTopLevelManager *TPM = PMD->getTopLevelManager(); - TPM->addIndirectPassManager(CGP); - - // [3] Assign manager to manage this new manager. This may create - // and push new managers into PMS - Pass *P = CGP; - TPM->schedulePass(P); - - // [4] Push new manager into PMS - PMS.push(CGP); - } - - CGP->add(this); -} - -/// For this class, we declare that we require and preserve the call graph. -/// If the derived class implements this method, it should -/// always explicitly call the implementation here. -void CallGraphSCCPass::getAnalysisUsage(AnalysisUsage &AU) const { - AU.addRequired(); - AU.addPreserved(); -} - - -//===----------------------------------------------------------------------===// -// PrintCallGraphPass Implementation -//===----------------------------------------------------------------------===// - -namespace { - /// PrintCallGraphPass - Print a Module corresponding to a call graph. - /// - class PrintCallGraphPass : public CallGraphSCCPass { - std::string Banner; - raw_ostream &Out; // raw_ostream to print on. - - public: - static char ID; - PrintCallGraphPass(const std::string &B, raw_ostream &o) - : CallGraphSCCPass(ID), Banner(B), Out(o) {} - - void getAnalysisUsage(AnalysisUsage &AU) const override { - AU.setPreservesAll(); - } - - bool runOnSCC(CallGraphSCC &SCC) override { - Out << Banner; - for (CallGraphNode *CGN : SCC) { - if (CGN->getFunction()) - CGN->getFunction()->print(Out); - else - Out << "\nPrinting Function\n"; - } - return false; - } - }; - -} // end anonymous namespace. - -char PrintCallGraphPass::ID = 0; - -Pass *CallGraphSCCPass::createPrinterPass(raw_ostream &O, - const std::string &Banner) const { - return new PrintCallGraphPass(Banner, O); -} - Index: llvm/trunk/lib/Analysis/IPA/CallPrinter.cpp =================================================================== --- llvm/trunk/lib/Analysis/IPA/CallPrinter.cpp +++ llvm/trunk/lib/Analysis/IPA/CallPrinter.cpp @@ -1,92 +0,0 @@ -//===- CallPrinter.cpp - DOT printer for call graph -----------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file defines '-dot-callgraph', which emit a callgraph..dot -// containing the call graph of a module. -// -// There is also a pass available to directly call dotty ('-view-callgraph'). -// -//===----------------------------------------------------------------------===// - -#include "llvm/Analysis/CallGraph.h" -#include "llvm/Analysis/CallPrinter.h" -#include "llvm/Analysis/DOTGraphTraitsPass.h" - -using namespace llvm; - -namespace llvm { - -template <> struct DOTGraphTraits : public DefaultDOTGraphTraits { - DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {} - - static std::string getGraphName(CallGraph *Graph) { return "Call graph"; } - - std::string getNodeLabel(CallGraphNode *Node, CallGraph *Graph) { - if (Function *Func = Node->getFunction()) - return Func->getName(); - - return "external node"; - } -}; - -struct AnalysisCallGraphWrapperPassTraits { - static CallGraph *getGraph(CallGraphWrapperPass *P) { - return &P->getCallGraph(); - } -}; - -} // end llvm namespace - -namespace { - -struct CallGraphViewer - : public DOTGraphTraitsModuleViewer { - static char ID; - - CallGraphViewer() - : DOTGraphTraitsModuleViewer( - "callgraph", ID) { - initializeCallGraphViewerPass(*PassRegistry::getPassRegistry()); - } -}; - -struct CallGraphPrinter : public DOTGraphTraitsModulePrinter< - CallGraphWrapperPass, true, CallGraph *, - AnalysisCallGraphWrapperPassTraits> { - static char ID; - - CallGraphPrinter() - : DOTGraphTraitsModulePrinter( - "callgraph", ID) { - initializeCallGraphPrinterPass(*PassRegistry::getPassRegistry()); - } -}; - -} // end anonymous namespace - -char CallGraphViewer::ID = 0; -INITIALIZE_PASS(CallGraphViewer, "view-callgraph", "View call graph", false, - false) - -char CallGraphPrinter::ID = 0; -INITIALIZE_PASS(CallGraphPrinter, "dot-callgraph", - "Print call graph to 'dot' file", false, false) - -// Create methods available outside of this file, to use them -// "include/llvm/LinkAllPasses.h". Otherwise the pass would be deleted by -// the link time optimization. - -ModulePass *llvm::createCallGraphViewerPass() { return new CallGraphViewer(); } - -ModulePass *llvm::createCallGraphPrinterPass() { - return new CallGraphPrinter(); -} Index: llvm/trunk/lib/Analysis/IPA/GlobalsModRef.cpp =================================================================== --- llvm/trunk/lib/Analysis/IPA/GlobalsModRef.cpp +++ llvm/trunk/lib/Analysis/IPA/GlobalsModRef.cpp @@ -1,798 +0,0 @@ -//===- GlobalsModRef.cpp - Simple Mod/Ref Analysis for Globals ------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This simple pass provides alias and mod/ref information for global values -// that do not have their address taken, and keeps track of whether functions -// read or write memory (are "pure"). For this simple (but very common) case, -// we can provide pretty accurate and useful information. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Analysis/GlobalsModRef.h" -#include "llvm/ADT/SCCIterator.h" -#include "llvm/ADT/SmallPtrSet.h" -#include "llvm/ADT/Statistic.h" -#include "llvm/Analysis/MemoryBuiltins.h" -#include "llvm/Analysis/ValueTracking.h" -#include "llvm/IR/DerivedTypes.h" -#include "llvm/IR/InstIterator.h" -#include "llvm/IR/Instructions.h" -#include "llvm/IR/IntrinsicInst.h" -#include "llvm/IR/Module.h" -#include "llvm/Pass.h" -#include "llvm/Support/CommandLine.h" -using namespace llvm; - -#define DEBUG_TYPE "globalsmodref-aa" - -STATISTIC(NumNonAddrTakenGlobalVars, - "Number of global vars without address taken"); -STATISTIC(NumNonAddrTakenFunctions,"Number of functions without address taken"); -STATISTIC(NumNoMemFunctions, "Number of functions that do not access memory"); -STATISTIC(NumReadMemFunctions, "Number of functions that only read memory"); -STATISTIC(NumIndirectGlobalVars, "Number of indirect global objects"); - -// An option to enable unsafe alias results from the GlobalsModRef analysis. -// When enabled, GlobalsModRef will provide no-alias results which in extremely -// rare cases may not be conservatively correct. In particular, in the face of -// transforms which cause assymetry between how effective GetUnderlyingObject -// is for two pointers, it may produce incorrect results. -// -// These unsafe results have been returned by GMR for many years without -// causing significant issues in the wild and so we provide a mechanism to -// re-enable them for users of LLVM that have a particular performance -// sensitivity and no known issues. The option also makes it easy to evaluate -// the performance impact of these results. -static cl::opt EnableUnsafeGlobalsModRefAliasResults( - "enable-unsafe-globalsmodref-alias-results", cl::init(false), cl::Hidden); - -/// The mod/ref information collected for a particular function. -/// -/// We collect information about mod/ref behavior of a function here, both in -/// general and as pertains to specific globals. We only have this detailed -/// information when we know *something* useful about the behavior. If we -/// saturate to fully general mod/ref, we remove the info for the function. -class GlobalsModRef::FunctionInfo { - typedef SmallDenseMap GlobalInfoMapType; - - /// Build a wrapper struct that has 8-byte alignment. All heap allocations - /// should provide this much alignment at least, but this makes it clear we - /// specifically rely on this amount of alignment. - struct LLVM_ALIGNAS(8) AlignedMap { - AlignedMap() {} - AlignedMap(const AlignedMap &Arg) : Map(Arg.Map) {} - GlobalInfoMapType Map; - }; - - /// Pointer traits for our aligned map. - struct AlignedMapPointerTraits { - static inline void *getAsVoidPointer(AlignedMap *P) { return P; } - static inline AlignedMap *getFromVoidPointer(void *P) { - return (AlignedMap *)P; - } - enum { NumLowBitsAvailable = 3 }; - static_assert(AlignOf::Alignment >= (1 << NumLowBitsAvailable), - "AlignedMap insufficiently aligned to have enough low bits."); - }; - - /// The bit that flags that this function may read any global. This is - /// chosen to mix together with ModRefInfo bits. - enum { MayReadAnyGlobal = 4 }; - - /// Checks to document the invariants of the bit packing here. - static_assert((MayReadAnyGlobal & MRI_ModRef) == 0, - "ModRef and the MayReadAnyGlobal flag bits overlap."); - static_assert(((MayReadAnyGlobal | MRI_ModRef) >> - AlignedMapPointerTraits::NumLowBitsAvailable) == 0, - "Insufficient low bits to store our flag and ModRef info."); - -public: - FunctionInfo() : Info() {} - ~FunctionInfo() { - delete Info.getPointer(); - } - // Spell out the copy ond move constructors and assignment operators to get - // deep copy semantics and correct move semantics in the face of the - // pointer-int pair. - FunctionInfo(const FunctionInfo &Arg) - : Info(nullptr, Arg.Info.getInt()) { - if (const auto *ArgPtr = Arg.Info.getPointer()) - Info.setPointer(new AlignedMap(*ArgPtr)); - } - FunctionInfo(FunctionInfo &&Arg) - : Info(Arg.Info.getPointer(), Arg.Info.getInt()) { - Arg.Info.setPointerAndInt(nullptr, 0); - } - FunctionInfo &operator=(const FunctionInfo &RHS) { - delete Info.getPointer(); - Info.setPointerAndInt(nullptr, RHS.Info.getInt()); - if (const auto *RHSPtr = RHS.Info.getPointer()) - Info.setPointer(new AlignedMap(*RHSPtr)); - return *this; - } - FunctionInfo &operator=(FunctionInfo &&RHS) { - delete Info.getPointer(); - Info.setPointerAndInt(RHS.Info.getPointer(), RHS.Info.getInt()); - RHS.Info.setPointerAndInt(nullptr, 0); - return *this; - } - - /// Returns the \c ModRefInfo info for this function. - ModRefInfo getModRefInfo() const { - return ModRefInfo(Info.getInt() & MRI_ModRef); - } - - /// Adds new \c ModRefInfo for this function to its state. - void addModRefInfo(ModRefInfo NewMRI) { - Info.setInt(Info.getInt() | NewMRI); - } - - /// Returns whether this function may read any global variable, and we don't - /// know which global. - bool mayReadAnyGlobal() const { return Info.getInt() & MayReadAnyGlobal; } - - /// Sets this function as potentially reading from any global. - void setMayReadAnyGlobal() { Info.setInt(Info.getInt() | MayReadAnyGlobal); } - - /// Returns the \c ModRefInfo info for this function w.r.t. a particular - /// global, which may be more precise than the general information above. - ModRefInfo getModRefInfoForGlobal(const GlobalValue &GV) const { - ModRefInfo GlobalMRI = mayReadAnyGlobal() ? MRI_Ref : MRI_NoModRef; - if (AlignedMap *P = Info.getPointer()) { - auto I = P->Map.find(&GV); - if (I != P->Map.end()) - GlobalMRI = ModRefInfo(GlobalMRI | I->second); - } - return GlobalMRI; - } - - /// Add mod/ref info from another function into ours, saturating towards - /// MRI_ModRef. - void addFunctionInfo(const FunctionInfo &FI) { - addModRefInfo(FI.getModRefInfo()); - - if (FI.mayReadAnyGlobal()) - setMayReadAnyGlobal(); - - if (AlignedMap *P = FI.Info.getPointer()) - for (const auto &G : P->Map) - addModRefInfoForGlobal(*G.first, G.second); - } - - void addModRefInfoForGlobal(const GlobalValue &GV, ModRefInfo NewMRI) { - AlignedMap *P = Info.getPointer(); - if (!P) { - P = new AlignedMap(); - Info.setPointer(P); - } - auto &GlobalMRI = P->Map[&GV]; - GlobalMRI = ModRefInfo(GlobalMRI | NewMRI); - } - - /// Clear a global's ModRef info. Should be used when a global is being - /// deleted. - void eraseModRefInfoForGlobal(const GlobalValue &GV) { - if (AlignedMap *P = Info.getPointer()) - P->Map.erase(&GV); - } - -private: - /// All of the information is encoded into a single pointer, with a three bit - /// integer in the low three bits. The high bit provides a flag for when this - /// function may read any global. The low two bits are the ModRefInfo. And - /// the pointer, when non-null, points to a map from GlobalValue to - /// ModRefInfo specific to that GlobalValue. - PointerIntPair Info; -}; - -void GlobalsModRef::DeletionCallbackHandle::deleted() { - Value *V = getValPtr(); - if (auto *F = dyn_cast(V)) - GMR.FunctionInfos.erase(F); - - if (GlobalValue *GV = dyn_cast(V)) { - if (GMR.NonAddressTakenGlobals.erase(GV)) { - // This global might be an indirect global. If so, remove it and - // remove any AllocRelatedValues for it. - if (GMR.IndirectGlobals.erase(GV)) { - // Remove any entries in AllocsForIndirectGlobals for this global. - for (auto I = GMR.AllocsForIndirectGlobals.begin(), - E = GMR.AllocsForIndirectGlobals.end(); - I != E; ++I) - if (I->second == GV) - GMR.AllocsForIndirectGlobals.erase(I); - } - - // Scan the function info we have collected and remove this global - // from all of them. - for (auto &FIPair : GMR.FunctionInfos) - FIPair.second.eraseModRefInfoForGlobal(*GV); - } - } - - // If this is an allocation related to an indirect global, remove it. - GMR.AllocsForIndirectGlobals.erase(V); - - // And clear out the handle. - setValPtr(nullptr); - GMR.Handles.erase(I); - // This object is now destroyed! -} - -char GlobalsModRef::ID = 0; -INITIALIZE_AG_PASS_BEGIN(GlobalsModRef, AliasAnalysis, "globalsmodref-aa", - "Simple mod/ref analysis for globals", false, true, - false) -INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass) -INITIALIZE_AG_PASS_END(GlobalsModRef, AliasAnalysis, "globalsmodref-aa", - "Simple mod/ref analysis for globals", false, true, - false) - -Pass *llvm::createGlobalsModRefPass() { return new GlobalsModRef(); } - -GlobalsModRef::GlobalsModRef() : ModulePass(ID) { - initializeGlobalsModRefPass(*PassRegistry::getPassRegistry()); -} - -FunctionModRefBehavior GlobalsModRef::getModRefBehavior(const Function *F) { - FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior; - - if (FunctionInfo *FI = getFunctionInfo(F)) { - if (FI->getModRefInfo() == MRI_NoModRef) - Min = FMRB_DoesNotAccessMemory; - else if ((FI->getModRefInfo() & MRI_Mod) == 0) - Min = FMRB_OnlyReadsMemory; - } - - return FunctionModRefBehavior(AliasAnalysis::getModRefBehavior(F) & Min); -} - -FunctionModRefBehavior GlobalsModRef::getModRefBehavior(ImmutableCallSite CS) { - FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior; - - if (const Function *F = CS.getCalledFunction()) - if (FunctionInfo *FI = getFunctionInfo(F)) { - if (FI->getModRefInfo() == MRI_NoModRef) - Min = FMRB_DoesNotAccessMemory; - else if ((FI->getModRefInfo() & MRI_Mod) == 0) - Min = FMRB_OnlyReadsMemory; - } - - return FunctionModRefBehavior(AliasAnalysis::getModRefBehavior(CS) & Min); -} - -/// Returns the function info for the function, or null if we don't have -/// anything useful to say about it. -GlobalsModRef::FunctionInfo *GlobalsModRef::getFunctionInfo(const Function *F) { - auto I = FunctionInfos.find(F); - if (I != FunctionInfos.end()) - return &I->second; - return nullptr; -} - -/// AnalyzeGlobals - Scan through the users of all of the internal -/// GlobalValue's in the program. If none of them have their "address taken" -/// (really, their address passed to something nontrivial), record this fact, -/// and record the functions that they are used directly in. -void GlobalsModRef::AnalyzeGlobals(Module &M) { - SmallPtrSet TrackedFunctions; - for (Function &F : M) - if (F.hasLocalLinkage()) - if (!AnalyzeUsesOfPointer(&F)) { - // Remember that we are tracking this global. - NonAddressTakenGlobals.insert(&F); - TrackedFunctions.insert(&F); - Handles.emplace_front(*this, &F); - Handles.front().I = Handles.begin(); - ++NumNonAddrTakenFunctions; - } - - SmallPtrSet Readers, Writers; - for (GlobalVariable &GV : M.globals()) - if (GV.hasLocalLinkage()) { - if (!AnalyzeUsesOfPointer(&GV, &Readers, - GV.isConstant() ? nullptr : &Writers)) { - // Remember that we are tracking this global, and the mod/ref fns - NonAddressTakenGlobals.insert(&GV); - Handles.emplace_front(*this, &GV); - Handles.front().I = Handles.begin(); - - for (Function *Reader : Readers) { - if (TrackedFunctions.insert(Reader).second) { - Handles.emplace_front(*this, Reader); - Handles.front().I = Handles.begin(); - } - FunctionInfos[Reader].addModRefInfoForGlobal(GV, MRI_Ref); - } - - if (!GV.isConstant()) // No need to keep track of writers to constants - for (Function *Writer : Writers) { - if (TrackedFunctions.insert(Writer).second) { - Handles.emplace_front(*this, Writer); - Handles.front().I = Handles.begin(); - } - FunctionInfos[Writer].addModRefInfoForGlobal(GV, MRI_Mod); - } - ++NumNonAddrTakenGlobalVars; - - // If this global holds a pointer type, see if it is an indirect global. - if (GV.getType()->getElementType()->isPointerTy() && - AnalyzeIndirectGlobalMemory(&GV)) - ++NumIndirectGlobalVars; - } - Readers.clear(); - Writers.clear(); - } -} - -/// AnalyzeUsesOfPointer - Look at all of the users of the specified pointer. -/// If this is used by anything complex (i.e., the address escapes), return -/// true. Also, while we are at it, keep track of those functions that read and -/// write to the value. -/// -/// If OkayStoreDest is non-null, stores into this global are allowed. -bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V, - SmallPtrSetImpl *Readers, - SmallPtrSetImpl *Writers, - GlobalValue *OkayStoreDest) { - if (!V->getType()->isPointerTy()) - return true; - - for (Use &U : V->uses()) { - User *I = U.getUser(); - if (LoadInst *LI = dyn_cast(I)) { - if (Readers) - Readers->insert(LI->getParent()->getParent()); - } else if (StoreInst *SI = dyn_cast(I)) { - if (V == SI->getOperand(1)) { - if (Writers) - Writers->insert(SI->getParent()->getParent()); - } else if (SI->getOperand(1) != OkayStoreDest) { - return true; // Storing the pointer - } - } else if (Operator::getOpcode(I) == Instruction::GetElementPtr) { - if (AnalyzeUsesOfPointer(I, Readers, Writers)) - return true; - } else if (Operator::getOpcode(I) == Instruction::BitCast) { - if (AnalyzeUsesOfPointer(I, Readers, Writers, OkayStoreDest)) - return true; - } else if (auto CS = CallSite(I)) { - // Make sure that this is just the function being called, not that it is - // passing into the function. - if (!CS.isCallee(&U)) { - // Detect calls to free. - if (isFreeCall(I, TLI)) { - if (Writers) - Writers->insert(CS->getParent()->getParent()); - } else { - return true; // Argument of an unknown call. - } - } - } else if (ICmpInst *ICI = dyn_cast(I)) { - if (!isa(ICI->getOperand(1))) - return true; // Allow comparison against null. - } else { - return true; - } - } - - return false; -} - -/// AnalyzeIndirectGlobalMemory - We found an non-address-taken global variable -/// which holds a pointer type. See if the global always points to non-aliased -/// heap memory: that is, all initializers of the globals are allocations, and -/// those allocations have no use other than initialization of the global. -/// Further, all loads out of GV must directly use the memory, not store the -/// pointer somewhere. If this is true, we consider the memory pointed to by -/// GV to be owned by GV and can disambiguate other pointers from it. -bool GlobalsModRef::AnalyzeIndirectGlobalMemory(GlobalValue *GV) { - // Keep track of values related to the allocation of the memory, f.e. the - // value produced by the malloc call and any casts. - std::vector AllocRelatedValues; - - // Walk the user list of the global. If we find anything other than a direct - // load or store, bail out. - for (User *U : GV->users()) { - if (LoadInst *LI = dyn_cast(U)) { - // The pointer loaded from the global can only be used in simple ways: - // we allow addressing of it and loading storing to it. We do *not* allow - // storing the loaded pointer somewhere else or passing to a function. - if (AnalyzeUsesOfPointer(LI)) - return false; // Loaded pointer escapes. - // TODO: Could try some IP mod/ref of the loaded pointer. - } else if (StoreInst *SI = dyn_cast(U)) { - // Storing the global itself. - if (SI->getOperand(0) == GV) - return false; - - // If storing the null pointer, ignore it. - if (isa(SI->getOperand(0))) - continue; - - // Check the value being stored. - Value *Ptr = GetUnderlyingObject(SI->getOperand(0), - GV->getParent()->getDataLayout()); - - if (!isAllocLikeFn(Ptr, TLI)) - return false; // Too hard to analyze. - - // Analyze all uses of the allocation. If any of them are used in a - // non-simple way (e.g. stored to another global) bail out. - if (AnalyzeUsesOfPointer(Ptr, /*Readers*/ nullptr, /*Writers*/ nullptr, - GV)) - return false; // Loaded pointer escapes. - - // Remember that this allocation is related to the indirect global. - AllocRelatedValues.push_back(Ptr); - } else { - // Something complex, bail out. - return false; - } - } - - // Okay, this is an indirect global. Remember all of the allocations for - // this global in AllocsForIndirectGlobals. - while (!AllocRelatedValues.empty()) { - AllocsForIndirectGlobals[AllocRelatedValues.back()] = GV; - Handles.emplace_front(*this, AllocRelatedValues.back()); - Handles.front().I = Handles.begin(); - AllocRelatedValues.pop_back(); - } - IndirectGlobals.insert(GV); - Handles.emplace_front(*this, GV); - Handles.front().I = Handles.begin(); - return true; -} - -/// AnalyzeCallGraph - At this point, we know the functions where globals are -/// immediately stored to and read from. Propagate this information up the call -/// graph to all callers and compute the mod/ref info for all memory for each -/// function. -void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) { - // We do a bottom-up SCC traversal of the call graph. In other words, we - // visit all callees before callers (leaf-first). - for (scc_iterator I = scc_begin(&CG); !I.isAtEnd(); ++I) { - const std::vector &SCC = *I; - assert(!SCC.empty() && "SCC with no functions?"); - - if (!SCC[0]->getFunction()) { - // Calls externally - can't say anything useful. Remove any existing - // function records (may have been created when scanning globals). - for (auto *Node : SCC) - FunctionInfos.erase(Node->getFunction()); - continue; - } - - FunctionInfo &FI = FunctionInfos[SCC[0]->getFunction()]; - bool KnowNothing = false; - - // Collect the mod/ref properties due to called functions. We only compute - // one mod-ref set. - for (unsigned i = 0, e = SCC.size(); i != e && !KnowNothing; ++i) { - Function *F = SCC[i]->getFunction(); - if (!F) { - KnowNothing = true; - break; - } - - if (F->isDeclaration()) { - // Try to get mod/ref behaviour from function attributes. - if (F->doesNotAccessMemory()) { - // Can't do better than that! - } else if (F->onlyReadsMemory()) { - FI.addModRefInfo(MRI_Ref); - if (!F->isIntrinsic()) - // This function might call back into the module and read a global - - // consider every global as possibly being read by this function. - FI.setMayReadAnyGlobal(); - } else { - FI.addModRefInfo(MRI_ModRef); - // Can't say anything useful unless it's an intrinsic - they don't - // read or write global variables of the kind considered here. - KnowNothing = !F->isIntrinsic(); - } - continue; - } - - for (CallGraphNode::iterator CI = SCC[i]->begin(), E = SCC[i]->end(); - CI != E && !KnowNothing; ++CI) - if (Function *Callee = CI->second->getFunction()) { - if (FunctionInfo *CalleeFI = getFunctionInfo(Callee)) { - // Propagate function effect up. - FI.addFunctionInfo(*CalleeFI); - } else { - // Can't say anything about it. However, if it is inside our SCC, - // then nothing needs to be done. - CallGraphNode *CalleeNode = CG[Callee]; - if (std::find(SCC.begin(), SCC.end(), CalleeNode) == SCC.end()) - KnowNothing = true; - } - } else { - KnowNothing = true; - } - } - - // If we can't say anything useful about this SCC, remove all SCC functions - // from the FunctionInfos map. - if (KnowNothing) { - for (auto *Node : SCC) - FunctionInfos.erase(Node->getFunction()); - continue; - } - - // Scan the function bodies for explicit loads or stores. - for (auto *Node : SCC) { - if (FI.getModRefInfo() == MRI_ModRef) - break; // The mod/ref lattice saturates here. - for (Instruction &I : instructions(Node->getFunction())) { - if (FI.getModRefInfo() == MRI_ModRef) - break; // The mod/ref lattice saturates here. - - // We handle calls specially because the graph-relevant aspects are - // handled above. - if (auto CS = CallSite(&I)) { - if (isAllocationFn(&I, TLI) || isFreeCall(&I, TLI)) { - // FIXME: It is completely unclear why this is necessary and not - // handled by the above graph code. - FI.addModRefInfo(MRI_ModRef); - } else if (Function *Callee = CS.getCalledFunction()) { - // The callgraph doesn't include intrinsic calls. - if (Callee->isIntrinsic()) { - FunctionModRefBehavior Behaviour = - AliasAnalysis::getModRefBehavior(Callee); - FI.addModRefInfo(ModRefInfo(Behaviour & MRI_ModRef)); - } - } - continue; - } - - // All non-call instructions we use the primary predicates for whether - // thay read or write memory. - if (I.mayReadFromMemory()) - FI.addModRefInfo(MRI_Ref); - if (I.mayWriteToMemory()) - FI.addModRefInfo(MRI_Mod); - } - } - - if ((FI.getModRefInfo() & MRI_Mod) == 0) - ++NumReadMemFunctions; - if (FI.getModRefInfo() == MRI_NoModRef) - ++NumNoMemFunctions; - - // Finally, now that we know the full effect on this SCC, clone the - // information to each function in the SCC. - for (unsigned i = 1, e = SCC.size(); i != e; ++i) - FunctionInfos[SCC[i]->getFunction()] = FI; - } -} - -// There are particular cases where we can conclude no-alias between -// a non-addr-taken global and some other underlying object. Specifically, -// a non-addr-taken global is known to not be escaped from any function. It is -// also incorrect for a transformation to introduce an escape of a global in -// a way that is observable when it was not there previously. One function -// being transformed to introduce an escape which could possibly be observed -// (via loading from a global or the return value for example) within another -// function is never safe. If the observation is made through non-atomic -// operations on different threads, it is a data-race and UB. If the -// observation is well defined, by being observed the transformation would have -// changed program behavior by introducing the observed escape, making it an -// invalid transform. -// -// This property does require that transformations which *temporarily* escape -// a global that was not previously escaped, prior to restoring it, cannot rely -// on the results of GMR::alias. This seems a reasonable restriction, although -// currently there is no way to enforce it. There is also no realistic -// optimization pass that would make this mistake. The closest example is -// a transformation pass which does reg2mem of SSA values but stores them into -// global variables temporarily before restoring the global variable's value. -// This could be useful to expose "benign" races for example. However, it seems -// reasonable to require that a pass which introduces escapes of global -// variables in this way to either not trust AA results while the escape is -// active, or to be forced to operate as a module pass that cannot co-exist -// with an alias analysis such as GMR. -bool GlobalsModRef::isNonEscapingGlobalNoAlias(const GlobalValue *GV, - const Value *V) { - // In order to know that the underlying object cannot alias the - // non-addr-taken global, we must know that it would have to be an escape. - // Thus if the underlying object is a function argument, a load from - // a global, or the return of a function, it cannot alias. We can also - // recurse through PHI nodes and select nodes provided all of their inputs - // resolve to one of these known-escaping roots. - SmallPtrSet Visited; - SmallVector Inputs; - Visited.insert(V); - Inputs.push_back(V); - int Depth = 0; - do { - const Value *Input = Inputs.pop_back_val(); - - if (auto *InputGV = dyn_cast(Input)) { - // If one input is the very global we're querying against, then we can't - // conclude no-alias. - if (InputGV == GV) - return false; - - // Distinct GlobalVariables never alias, unless overriden or zero-sized. - // FIXME: The condition can be refined, but be conservative for now. - auto *GVar = dyn_cast(GV); - auto *InputGVar = dyn_cast(InputGV); - if (GVar && InputGVar && - !GVar->isDeclaration() && !InputGVar->isDeclaration() && - !GVar->mayBeOverridden() && !InputGVar->mayBeOverridden()) { - Type *GVType = GVar->getInitializer()->getType(); - Type *InputGVType = InputGVar->getInitializer()->getType(); - if (GVType->isSized() && InputGVType->isSized() && - (DL->getTypeAllocSize(GVType) > 0) && - (DL->getTypeAllocSize(InputGVType) > 0)) - continue; - } - - // Conservatively return false, even though we could be smarter - // (e.g. look through GlobalAliases). - return false; - } - - if (isa(Input) || isa(Input) || - isa(Input)) { - // Arguments to functions or returns from functions are inherently - // escaping, so we can immediately classify those as not aliasing any - // non-addr-taken globals. - continue; - } - if (auto *LI = dyn_cast(Input)) { - // A pointer loaded from a global would have been captured, and we know - // that the global is non-escaping, so no alias. - if (isa(GetUnderlyingObject(LI->getPointerOperand(), *DL))) - continue; - - // Otherwise, a load could come from anywhere, so bail. - return false; - } - - // Recurse through a limited number of selects and PHIs. This is an - // arbitrary depth of 4, lower numbers could be used to fix compile time - // issues if needed, but this is generally expected to be only be important - // for small depths. - if (++Depth > 4) - return false; - if (auto *SI = dyn_cast(Input)) { - const Value *LHS = GetUnderlyingObject(SI->getTrueValue(), *DL); - const Value *RHS = GetUnderlyingObject(SI->getFalseValue(), *DL); - if (Visited.insert(LHS).second) - Inputs.push_back(LHS); - if (Visited.insert(RHS).second) - Inputs.push_back(RHS); - continue; - } - if (auto *PN = dyn_cast(Input)) { - for (const Value *Op : PN->incoming_values()) { - Op = GetUnderlyingObject(Op, *DL); - if (Visited.insert(Op).second) - Inputs.push_back(Op); - } - continue; - } - - // FIXME: It would be good to handle other obvious no-alias cases here, but - // it isn't clear how to do so reasonbly without building a small version - // of BasicAA into this code. We could recurse into AliasAnalysis::alias - // here but that seems likely to go poorly as we're inside the - // implementation of such a query. Until then, just conservatievly retun - // false. - return false; - } while (!Inputs.empty()); - - // If all the inputs to V were definitively no-alias, then V is no-alias. - return true; -} - -/// alias - If one of the pointers is to a global that we are tracking, and the -/// other is some random pointer, we know there cannot be an alias, because the -/// address of the global isn't taken. -AliasResult GlobalsModRef::alias(const MemoryLocation &LocA, - const MemoryLocation &LocB) { - // Get the base object these pointers point to. - const Value *UV1 = GetUnderlyingObject(LocA.Ptr, *DL); - const Value *UV2 = GetUnderlyingObject(LocB.Ptr, *DL); - - // If either of the underlying values is a global, they may be non-addr-taken - // globals, which we can answer queries about. - const GlobalValue *GV1 = dyn_cast(UV1); - const GlobalValue *GV2 = dyn_cast(UV2); - if (GV1 || GV2) { - // If the global's address is taken, pretend we don't know it's a pointer to - // the global. - if (GV1 && !NonAddressTakenGlobals.count(GV1)) - GV1 = nullptr; - if (GV2 && !NonAddressTakenGlobals.count(GV2)) - GV2 = nullptr; - - // If the two pointers are derived from two different non-addr-taken - // globals we know these can't alias. - if (GV1 && GV2 && GV1 != GV2) - return NoAlias; - - // If one is and the other isn't, it isn't strictly safe but we can fake - // this result if necessary for performance. This does not appear to be - // a common problem in practice. - if (EnableUnsafeGlobalsModRefAliasResults) - if ((GV1 || GV2) && GV1 != GV2) - return NoAlias; - - // Check for a special case where a non-escaping global can be used to - // conclude no-alias. - if ((GV1 || GV2) && GV1 != GV2) { - const GlobalValue *GV = GV1 ? GV1 : GV2; - const Value *UV = GV1 ? UV2 : UV1; - if (isNonEscapingGlobalNoAlias(GV, UV)) - return NoAlias; - } - - // Otherwise if they are both derived from the same addr-taken global, we - // can't know the two accesses don't overlap. - } - - // These pointers may be based on the memory owned by an indirect global. If - // so, we may be able to handle this. First check to see if the base pointer - // is a direct load from an indirect global. - GV1 = GV2 = nullptr; - if (const LoadInst *LI = dyn_cast(UV1)) - if (GlobalVariable *GV = dyn_cast(LI->getOperand(0))) - if (IndirectGlobals.count(GV)) - GV1 = GV; - if (const LoadInst *LI = dyn_cast(UV2)) - if (const GlobalVariable *GV = dyn_cast(LI->getOperand(0))) - if (IndirectGlobals.count(GV)) - GV2 = GV; - - // These pointers may also be from an allocation for the indirect global. If - // so, also handle them. - if (!GV1) - GV1 = AllocsForIndirectGlobals.lookup(UV1); - if (!GV2) - GV2 = AllocsForIndirectGlobals.lookup(UV2); - - // Now that we know whether the two pointers are related to indirect globals, - // use this to disambiguate the pointers. If the pointers are based on - // different indirect globals they cannot alias. - if (GV1 && GV2 && GV1 != GV2) - return NoAlias; - - // If one is based on an indirect global and the other isn't, it isn't - // strictly safe but we can fake this result if necessary for performance. - // This does not appear to be a common problem in practice. - if (EnableUnsafeGlobalsModRefAliasResults) - if ((GV1 || GV2) && GV1 != GV2) - return NoAlias; - - return AliasAnalysis::alias(LocA, LocB); -} - -ModRefInfo GlobalsModRef::getModRefInfo(ImmutableCallSite CS, - const MemoryLocation &Loc) { - unsigned Known = MRI_ModRef; - - // If we are asking for mod/ref info of a direct call with a pointer to a - // global we are tracking, return information if we have it. - const DataLayout &DL = CS.getCaller()->getParent()->getDataLayout(); - if (const GlobalValue *GV = - dyn_cast(GetUnderlyingObject(Loc.Ptr, DL))) - if (GV->hasLocalLinkage()) - if (const Function *F = CS.getCalledFunction()) - if (NonAddressTakenGlobals.count(GV)) - if (const FunctionInfo *FI = getFunctionInfo(F)) - Known = FI->getModRefInfoForGlobal(*GV); - - if (Known == MRI_NoModRef) - return MRI_NoModRef; // No need to query other mod/ref analyses - return ModRefInfo(Known & AliasAnalysis::getModRefInfo(CS, Loc)); -} Index: llvm/trunk/lib/Analysis/IPA/IPA.cpp =================================================================== --- llvm/trunk/lib/Analysis/IPA/IPA.cpp +++ llvm/trunk/lib/Analysis/IPA/IPA.cpp @@ -1,30 +0,0 @@ -//===-- IPA.cpp -----------------------------------------------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements the common initialization routines for the IPA library. -// -//===----------------------------------------------------------------------===// - -#include "llvm/InitializePasses.h" -#include "llvm-c/Initialization.h" -#include "llvm/PassRegistry.h" - -using namespace llvm; - -/// initializeIPA - Initialize all passes linked into the IPA library. -void llvm::initializeIPA(PassRegistry &Registry) { - initializeCallGraphWrapperPassPass(Registry); - initializeCallGraphPrinterPass(Registry); - initializeCallGraphViewerPass(Registry); - initializeGlobalsModRefPass(Registry); -} - -void LLVMInitializeIPA(LLVMPassRegistryRef R) { - initializeIPA(*unwrap(R)); -} Index: llvm/trunk/lib/Analysis/IPA/InlineCost.cpp =================================================================== --- llvm/trunk/lib/Analysis/IPA/InlineCost.cpp +++ llvm/trunk/lib/Analysis/IPA/InlineCost.cpp @@ -1,1451 +0,0 @@ -//===- InlineCost.cpp - Cost analysis for inliner -------------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements inline cost analysis. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Analysis/InlineCost.h" -#include "llvm/ADT/STLExtras.h" -#include "llvm/ADT/SetVector.h" -#include "llvm/ADT/SmallPtrSet.h" -#include "llvm/ADT/SmallVector.h" -#include "llvm/ADT/Statistic.h" -#include "llvm/Analysis/AssumptionCache.h" -#include "llvm/Analysis/CodeMetrics.h" -#include "llvm/Analysis/ConstantFolding.h" -#include "llvm/Analysis/InstructionSimplify.h" -#include "llvm/Analysis/TargetTransformInfo.h" -#include "llvm/IR/CallSite.h" -#include "llvm/IR/CallingConv.h" -#include "llvm/IR/DataLayout.h" -#include "llvm/IR/GetElementPtrTypeIterator.h" -#include "llvm/IR/GlobalAlias.h" -#include "llvm/IR/InstVisitor.h" -#include "llvm/IR/IntrinsicInst.h" -#include "llvm/IR/Operator.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/raw_ostream.h" - -using namespace llvm; - -#define DEBUG_TYPE "inline-cost" - -STATISTIC(NumCallsAnalyzed, "Number of call sites analyzed"); - -namespace { - -class CallAnalyzer : public InstVisitor { - typedef InstVisitor Base; - friend class InstVisitor; - - /// The TargetTransformInfo available for this compilation. - const TargetTransformInfo &TTI; - - /// The cache of @llvm.assume intrinsics. - AssumptionCacheTracker *ACT; - - // The called function. - Function &F; - - // The candidate callsite being analyzed. Please do not use this to do - // analysis in the caller function; we want the inline cost query to be - // easily cacheable. Instead, use the cover function paramHasAttr. - CallSite CandidateCS; - - int Threshold; - int Cost; - - bool IsCallerRecursive; - bool IsRecursiveCall; - bool ExposesReturnsTwice; - bool HasDynamicAlloca; - bool ContainsNoDuplicateCall; - bool HasReturn; - bool HasIndirectBr; - bool HasFrameEscape; - - /// Number of bytes allocated statically by the callee. - uint64_t AllocatedSize; - unsigned NumInstructions, NumVectorInstructions; - int FiftyPercentVectorBonus, TenPercentVectorBonus; - int VectorBonus; - - // While we walk the potentially-inlined instructions, we build up and - // maintain a mapping of simplified values specific to this callsite. The - // idea is to propagate any special information we have about arguments to - // this call through the inlinable section of the function, and account for - // likely simplifications post-inlining. The most important aspect we track - // is CFG altering simplifications -- when we prove a basic block dead, that - // can cause dramatic shifts in the cost of inlining a function. - DenseMap SimplifiedValues; - - // Keep track of the values which map back (through function arguments) to - // allocas on the caller stack which could be simplified through SROA. - DenseMap SROAArgValues; - - // The mapping of caller Alloca values to their accumulated cost savings. If - // we have to disable SROA for one of the allocas, this tells us how much - // cost must be added. - DenseMap SROAArgCosts; - - // Keep track of values which map to a pointer base and constant offset. - DenseMap > ConstantOffsetPtrs; - - // Custom simplification helper routines. - bool isAllocaDerivedArg(Value *V); - bool lookupSROAArgAndCost(Value *V, Value *&Arg, - DenseMap::iterator &CostIt); - void disableSROA(DenseMap::iterator CostIt); - void disableSROA(Value *V); - void accumulateSROACost(DenseMap::iterator CostIt, - int InstructionCost); - bool isGEPOffsetConstant(GetElementPtrInst &GEP); - bool accumulateGEPOffset(GEPOperator &GEP, APInt &Offset); - bool simplifyCallSite(Function *F, CallSite CS); - ConstantInt *stripAndComputeInBoundsConstantOffsets(Value *&V); - - /// Return true if the given argument to the function being considered for - /// inlining has the given attribute set either at the call site or the - /// function declaration. Primarily used to inspect call site specific - /// attributes since these can be more precise than the ones on the callee - /// itself. - bool paramHasAttr(Argument *A, Attribute::AttrKind Attr); - - /// Return true if the given value is known non null within the callee if - /// inlined through this particular callsite. - bool isKnownNonNullInCallee(Value *V); - - // Custom analysis routines. - bool analyzeBlock(BasicBlock *BB, SmallPtrSetImpl &EphValues); - - // Disable several entry points to the visitor so we don't accidentally use - // them by declaring but not defining them here. - void visit(Module *); void visit(Module &); - void visit(Function *); void visit(Function &); - void visit(BasicBlock *); void visit(BasicBlock &); - - // Provide base case for our instruction visit. - bool visitInstruction(Instruction &I); - - // Our visit overrides. - bool visitAlloca(AllocaInst &I); - bool visitPHI(PHINode &I); - bool visitGetElementPtr(GetElementPtrInst &I); - bool visitBitCast(BitCastInst &I); - bool visitPtrToInt(PtrToIntInst &I); - bool visitIntToPtr(IntToPtrInst &I); - bool visitCastInst(CastInst &I); - bool visitUnaryInstruction(UnaryInstruction &I); - bool visitCmpInst(CmpInst &I); - bool visitSub(BinaryOperator &I); - bool visitBinaryOperator(BinaryOperator &I); - bool visitLoad(LoadInst &I); - bool visitStore(StoreInst &I); - bool visitExtractValue(ExtractValueInst &I); - bool visitInsertValue(InsertValueInst &I); - bool visitCallSite(CallSite CS); - bool visitReturnInst(ReturnInst &RI); - bool visitBranchInst(BranchInst &BI); - bool visitSwitchInst(SwitchInst &SI); - bool visitIndirectBrInst(IndirectBrInst &IBI); - bool visitResumeInst(ResumeInst &RI); - bool visitCleanupReturnInst(CleanupReturnInst &RI); - bool visitCatchReturnInst(CatchReturnInst &RI); - bool visitUnreachableInst(UnreachableInst &I); - -public: - CallAnalyzer(const TargetTransformInfo &TTI, AssumptionCacheTracker *ACT, - Function &Callee, int Threshold, CallSite CSArg) - : TTI(TTI), ACT(ACT), F(Callee), CandidateCS(CSArg), Threshold(Threshold), - Cost(0), IsCallerRecursive(false), IsRecursiveCall(false), - ExposesReturnsTwice(false), HasDynamicAlloca(false), - ContainsNoDuplicateCall(false), HasReturn(false), HasIndirectBr(false), - HasFrameEscape(false), AllocatedSize(0), NumInstructions(0), - NumVectorInstructions(0), FiftyPercentVectorBonus(0), - TenPercentVectorBonus(0), VectorBonus(0), NumConstantArgs(0), - NumConstantOffsetPtrArgs(0), NumAllocaArgs(0), NumConstantPtrCmps(0), - NumConstantPtrDiffs(0), NumInstructionsSimplified(0), - SROACostSavings(0), SROACostSavingsLost(0) {} - - bool analyzeCall(CallSite CS); - - int getThreshold() { return Threshold; } - int getCost() { return Cost; } - - // Keep a bunch of stats about the cost savings found so we can print them - // out when debugging. - unsigned NumConstantArgs; - unsigned NumConstantOffsetPtrArgs; - unsigned NumAllocaArgs; - unsigned NumConstantPtrCmps; - unsigned NumConstantPtrDiffs; - unsigned NumInstructionsSimplified; - unsigned SROACostSavings; - unsigned SROACostSavingsLost; - - void dump(); -}; - -} // namespace - -/// \brief Test whether the given value is an Alloca-derived function argument. -bool CallAnalyzer::isAllocaDerivedArg(Value *V) { - return SROAArgValues.count(V); -} - -/// \brief Lookup the SROA-candidate argument and cost iterator which V maps to. -/// Returns false if V does not map to a SROA-candidate. -bool CallAnalyzer::lookupSROAArgAndCost( - Value *V, Value *&Arg, DenseMap::iterator &CostIt) { - if (SROAArgValues.empty() || SROAArgCosts.empty()) - return false; - - DenseMap::iterator ArgIt = SROAArgValues.find(V); - if (ArgIt == SROAArgValues.end()) - return false; - - Arg = ArgIt->second; - CostIt = SROAArgCosts.find(Arg); - return CostIt != SROAArgCosts.end(); -} - -/// \brief Disable SROA for the candidate marked by this cost iterator. -/// -/// This marks the candidate as no longer viable for SROA, and adds the cost -/// savings associated with it back into the inline cost measurement. -void CallAnalyzer::disableSROA(DenseMap::iterator CostIt) { - // If we're no longer able to perform SROA we need to undo its cost savings - // and prevent subsequent analysis. - Cost += CostIt->second; - SROACostSavings -= CostIt->second; - SROACostSavingsLost += CostIt->second; - SROAArgCosts.erase(CostIt); -} - -/// \brief If 'V' maps to a SROA candidate, disable SROA for it. -void CallAnalyzer::disableSROA(Value *V) { - Value *SROAArg; - DenseMap::iterator CostIt; - if (lookupSROAArgAndCost(V, SROAArg, CostIt)) - disableSROA(CostIt); -} - -/// \brief Accumulate the given cost for a particular SROA candidate. -void CallAnalyzer::accumulateSROACost(DenseMap::iterator CostIt, - int InstructionCost) { - CostIt->second += InstructionCost; - SROACostSavings += InstructionCost; -} - -/// \brief Check whether a GEP's indices are all constant. -/// -/// Respects any simplified values known during the analysis of this callsite. -bool CallAnalyzer::isGEPOffsetConstant(GetElementPtrInst &GEP) { - for (User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); I != E; ++I) - if (!isa(*I) && !SimplifiedValues.lookup(*I)) - return false; - - return true; -} - -/// \brief Accumulate a constant GEP offset into an APInt if possible. -/// -/// Returns false if unable to compute the offset for any reason. Respects any -/// simplified values known during the analysis of this callsite. -bool CallAnalyzer::accumulateGEPOffset(GEPOperator &GEP, APInt &Offset) { - const DataLayout &DL = F.getParent()->getDataLayout(); - unsigned IntPtrWidth = DL.getPointerSizeInBits(); - assert(IntPtrWidth == Offset.getBitWidth()); - - for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP); - GTI != GTE; ++GTI) { - ConstantInt *OpC = dyn_cast(GTI.getOperand()); - if (!OpC) - if (Constant *SimpleOp = SimplifiedValues.lookup(GTI.getOperand())) - OpC = dyn_cast(SimpleOp); - if (!OpC) - return false; - if (OpC->isZero()) continue; - - // Handle a struct index, which adds its field offset to the pointer. - if (StructType *STy = dyn_cast(*GTI)) { - unsigned ElementIdx = OpC->getZExtValue(); - const StructLayout *SL = DL.getStructLayout(STy); - Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx)); - continue; - } - - APInt TypeSize(IntPtrWidth, DL.getTypeAllocSize(GTI.getIndexedType())); - Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize; - } - return true; -} - -bool CallAnalyzer::visitAlloca(AllocaInst &I) { - // Check whether inlining will turn a dynamic alloca into a static - // alloca, and handle that case. - if (I.isArrayAllocation()) { - if (Constant *Size = SimplifiedValues.lookup(I.getArraySize())) { - ConstantInt *AllocSize = dyn_cast(Size); - assert(AllocSize && "Allocation size not a constant int?"); - Type *Ty = I.getAllocatedType(); - AllocatedSize += Ty->getPrimitiveSizeInBits() * AllocSize->getZExtValue(); - return Base::visitAlloca(I); - } - } - - // Accumulate the allocated size. - if (I.isStaticAlloca()) { - const DataLayout &DL = F.getParent()->getDataLayout(); - Type *Ty = I.getAllocatedType(); - AllocatedSize += DL.getTypeAllocSize(Ty); - } - - // We will happily inline static alloca instructions. - if (I.isStaticAlloca()) - return Base::visitAlloca(I); - - // FIXME: This is overly conservative. Dynamic allocas are inefficient for - // a variety of reasons, and so we would like to not inline them into - // functions which don't currently have a dynamic alloca. This simply - // disables inlining altogether in the presence of a dynamic alloca. - HasDynamicAlloca = true; - return false; -} - -bool CallAnalyzer::visitPHI(PHINode &I) { - // FIXME: We should potentially be tracking values through phi nodes, - // especially when they collapse to a single value due to deleted CFG edges - // during inlining. - - // FIXME: We need to propagate SROA *disabling* through phi nodes, even - // though we don't want to propagate it's bonuses. The idea is to disable - // SROA if it *might* be used in an inappropriate manner. - - // Phi nodes are always zero-cost. - return true; -} - -bool CallAnalyzer::visitGetElementPtr(GetElementPtrInst &I) { - Value *SROAArg; - DenseMap::iterator CostIt; - bool SROACandidate = lookupSROAArgAndCost(I.getPointerOperand(), - SROAArg, CostIt); - - // Try to fold GEPs of constant-offset call site argument pointers. This - // requires target data and inbounds GEPs. - if (I.isInBounds()) { - // Check if we have a base + offset for the pointer. - Value *Ptr = I.getPointerOperand(); - std::pair BaseAndOffset = ConstantOffsetPtrs.lookup(Ptr); - if (BaseAndOffset.first) { - // Check if the offset of this GEP is constant, and if so accumulate it - // into Offset. - if (!accumulateGEPOffset(cast(I), BaseAndOffset.second)) { - // Non-constant GEPs aren't folded, and disable SROA. - if (SROACandidate) - disableSROA(CostIt); - return false; - } - - // Add the result as a new mapping to Base + Offset. - ConstantOffsetPtrs[&I] = BaseAndOffset; - - // Also handle SROA candidates here, we already know that the GEP is - // all-constant indexed. - if (SROACandidate) - SROAArgValues[&I] = SROAArg; - - return true; - } - } - - if (isGEPOffsetConstant(I)) { - if (SROACandidate) - SROAArgValues[&I] = SROAArg; - - // Constant GEPs are modeled as free. - return true; - } - - // Variable GEPs will require math and will disable SROA. - if (SROACandidate) - disableSROA(CostIt); - return false; -} - -bool CallAnalyzer::visitBitCast(BitCastInst &I) { - // Propagate constants through bitcasts. - Constant *COp = dyn_cast(I.getOperand(0)); - if (!COp) - COp = SimplifiedValues.lookup(I.getOperand(0)); - if (COp) - if (Constant *C = ConstantExpr::getBitCast(COp, I.getType())) { - SimplifiedValues[&I] = C; - return true; - } - - // Track base/offsets through casts - std::pair BaseAndOffset - = ConstantOffsetPtrs.lookup(I.getOperand(0)); - // Casts don't change the offset, just wrap it up. - if (BaseAndOffset.first) - ConstantOffsetPtrs[&I] = BaseAndOffset; - - // Also look for SROA candidates here. - Value *SROAArg; - DenseMap::iterator CostIt; - if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) - SROAArgValues[&I] = SROAArg; - - // Bitcasts are always zero cost. - return true; -} - -bool CallAnalyzer::visitPtrToInt(PtrToIntInst &I) { - // Propagate constants through ptrtoint. - Constant *COp = dyn_cast(I.getOperand(0)); - if (!COp) - COp = SimplifiedValues.lookup(I.getOperand(0)); - if (COp) - if (Constant *C = ConstantExpr::getPtrToInt(COp, I.getType())) { - SimplifiedValues[&I] = C; - return true; - } - - // Track base/offset pairs when converted to a plain integer provided the - // integer is large enough to represent the pointer. - unsigned IntegerSize = I.getType()->getScalarSizeInBits(); - const DataLayout &DL = F.getParent()->getDataLayout(); - if (IntegerSize >= DL.getPointerSizeInBits()) { - std::pair BaseAndOffset - = ConstantOffsetPtrs.lookup(I.getOperand(0)); - if (BaseAndOffset.first) - ConstantOffsetPtrs[&I] = BaseAndOffset; - } - - // This is really weird. Technically, ptrtoint will disable SROA. However, - // unless that ptrtoint is *used* somewhere in the live basic blocks after - // inlining, it will be nuked, and SROA should proceed. All of the uses which - // would block SROA would also block SROA if applied directly to a pointer, - // and so we can just add the integer in here. The only places where SROA is - // preserved either cannot fire on an integer, or won't in-and-of themselves - // disable SROA (ext) w/o some later use that we would see and disable. - Value *SROAArg; - DenseMap::iterator CostIt; - if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) - SROAArgValues[&I] = SROAArg; - - return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I); -} - -bool CallAnalyzer::visitIntToPtr(IntToPtrInst &I) { - // Propagate constants through ptrtoint. - Constant *COp = dyn_cast(I.getOperand(0)); - if (!COp) - COp = SimplifiedValues.lookup(I.getOperand(0)); - if (COp) - if (Constant *C = ConstantExpr::getIntToPtr(COp, I.getType())) { - SimplifiedValues[&I] = C; - return true; - } - - // Track base/offset pairs when round-tripped through a pointer without - // modifications provided the integer is not too large. - Value *Op = I.getOperand(0); - unsigned IntegerSize = Op->getType()->getScalarSizeInBits(); - const DataLayout &DL = F.getParent()->getDataLayout(); - if (IntegerSize <= DL.getPointerSizeInBits()) { - std::pair BaseAndOffset = ConstantOffsetPtrs.lookup(Op); - if (BaseAndOffset.first) - ConstantOffsetPtrs[&I] = BaseAndOffset; - } - - // "Propagate" SROA here in the same manner as we do for ptrtoint above. - Value *SROAArg; - DenseMap::iterator CostIt; - if (lookupSROAArgAndCost(Op, SROAArg, CostIt)) - SROAArgValues[&I] = SROAArg; - - return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I); -} - -bool CallAnalyzer::visitCastInst(CastInst &I) { - // Propagate constants through ptrtoint. - Constant *COp = dyn_cast(I.getOperand(0)); - if (!COp) - COp = SimplifiedValues.lookup(I.getOperand(0)); - if (COp) - if (Constant *C = ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) { - SimplifiedValues[&I] = C; - return true; - } - - // Disable SROA in the face of arbitrary casts we don't whitelist elsewhere. - disableSROA(I.getOperand(0)); - - return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I); -} - -bool CallAnalyzer::visitUnaryInstruction(UnaryInstruction &I) { - Value *Operand = I.getOperand(0); - Constant *COp = dyn_cast(Operand); - if (!COp) - COp = SimplifiedValues.lookup(Operand); - if (COp) { - const DataLayout &DL = F.getParent()->getDataLayout(); - if (Constant *C = ConstantFoldInstOperands(I.getOpcode(), I.getType(), - COp, DL)) { - SimplifiedValues[&I] = C; - return true; - } - } - - // Disable any SROA on the argument to arbitrary unary operators. - disableSROA(Operand); - - return false; -} - -bool CallAnalyzer::paramHasAttr(Argument *A, Attribute::AttrKind Attr) { - unsigned ArgNo = A->getArgNo(); - return CandidateCS.paramHasAttr(ArgNo+1, Attr); -} - -bool CallAnalyzer::isKnownNonNullInCallee(Value *V) { - // Does the *call site* have the NonNull attribute set on an argument? We - // use the attribute on the call site to memoize any analysis done in the - // caller. This will also trip if the callee function has a non-null - // parameter attribute, but that's a less interesting case because hopefully - // the callee would already have been simplified based on that. - if (Argument *A = dyn_cast(V)) - if (paramHasAttr(A, Attribute::NonNull)) - return true; - - // Is this an alloca in the caller? This is distinct from the attribute case - // above because attributes aren't updated within the inliner itself and we - // always want to catch the alloca derived case. - if (isAllocaDerivedArg(V)) - // We can actually predict the result of comparisons between an - // alloca-derived value and null. Note that this fires regardless of - // SROA firing. - return true; - - return false; -} - -bool CallAnalyzer::visitCmpInst(CmpInst &I) { - Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); - // First try to handle simplified comparisons. - if (!isa(LHS)) - if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS)) - LHS = SimpleLHS; - if (!isa(RHS)) - if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) - RHS = SimpleRHS; - if (Constant *CLHS = dyn_cast(LHS)) { - if (Constant *CRHS = dyn_cast(RHS)) - if (Constant *C = ConstantExpr::getCompare(I.getPredicate(), CLHS, CRHS)) { - SimplifiedValues[&I] = C; - return true; - } - } - - if (I.getOpcode() == Instruction::FCmp) - return false; - - // Otherwise look for a comparison between constant offset pointers with - // a common base. - Value *LHSBase, *RHSBase; - APInt LHSOffset, RHSOffset; - std::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS); - if (LHSBase) { - std::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS); - if (RHSBase && LHSBase == RHSBase) { - // We have common bases, fold the icmp to a constant based on the - // offsets. - Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset); - Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset); - if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) { - SimplifiedValues[&I] = C; - ++NumConstantPtrCmps; - return true; - } - } - } - - // If the comparison is an equality comparison with null, we can simplify it - // if we know the value (argument) can't be null - if (I.isEquality() && isa(I.getOperand(1)) && - isKnownNonNullInCallee(I.getOperand(0))) { - bool IsNotEqual = I.getPredicate() == CmpInst::ICMP_NE; - SimplifiedValues[&I] = IsNotEqual ? ConstantInt::getTrue(I.getType()) - : ConstantInt::getFalse(I.getType()); - return true; - } - // Finally check for SROA candidates in comparisons. - Value *SROAArg; - DenseMap::iterator CostIt; - if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) { - if (isa(I.getOperand(1))) { - accumulateSROACost(CostIt, InlineConstants::InstrCost); - return true; - } - - disableSROA(CostIt); - } - - return false; -} - -bool CallAnalyzer::visitSub(BinaryOperator &I) { - // Try to handle a special case: we can fold computing the difference of two - // constant-related pointers. - Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); - Value *LHSBase, *RHSBase; - APInt LHSOffset, RHSOffset; - std::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS); - if (LHSBase) { - std::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS); - if (RHSBase && LHSBase == RHSBase) { - // We have common bases, fold the subtract to a constant based on the - // offsets. - Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset); - Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset); - if (Constant *C = ConstantExpr::getSub(CLHS, CRHS)) { - SimplifiedValues[&I] = C; - ++NumConstantPtrDiffs; - return true; - } - } - } - - // Otherwise, fall back to the generic logic for simplifying and handling - // instructions. - return Base::visitSub(I); -} - -bool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) { - Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); - const DataLayout &DL = F.getParent()->getDataLayout(); - if (!isa(LHS)) - if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS)) - LHS = SimpleLHS; - if (!isa(RHS)) - if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) - RHS = SimpleRHS; - Value *SimpleV = nullptr; - if (auto FI = dyn_cast(&I)) - SimpleV = - SimplifyFPBinOp(I.getOpcode(), LHS, RHS, FI->getFastMathFlags(), DL); - else - SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL); - - if (Constant *C = dyn_cast_or_null(SimpleV)) { - SimplifiedValues[&I] = C; - return true; - } - - // Disable any SROA on arguments to arbitrary, unsimplified binary operators. - disableSROA(LHS); - disableSROA(RHS); - - return false; -} - -bool CallAnalyzer::visitLoad(LoadInst &I) { - Value *SROAArg; - DenseMap::iterator CostIt; - if (lookupSROAArgAndCost(I.getPointerOperand(), SROAArg, CostIt)) { - if (I.isSimple()) { - accumulateSROACost(CostIt, InlineConstants::InstrCost); - return true; - } - - disableSROA(CostIt); - } - - return false; -} - -bool CallAnalyzer::visitStore(StoreInst &I) { - Value *SROAArg; - DenseMap::iterator CostIt; - if (lookupSROAArgAndCost(I.getPointerOperand(), SROAArg, CostIt)) { - if (I.isSimple()) { - accumulateSROACost(CostIt, InlineConstants::InstrCost); - return true; - } - - disableSROA(CostIt); - } - - return false; -} - -bool CallAnalyzer::visitExtractValue(ExtractValueInst &I) { - // Constant folding for extract value is trivial. - Constant *C = dyn_cast(I.getAggregateOperand()); - if (!C) - C = SimplifiedValues.lookup(I.getAggregateOperand()); - if (C) { - SimplifiedValues[&I] = ConstantExpr::getExtractValue(C, I.getIndices()); - return true; - } - - // SROA can look through these but give them a cost. - return false; -} - -bool CallAnalyzer::visitInsertValue(InsertValueInst &I) { - // Constant folding for insert value is trivial. - Constant *AggC = dyn_cast(I.getAggregateOperand()); - if (!AggC) - AggC = SimplifiedValues.lookup(I.getAggregateOperand()); - Constant *InsertedC = dyn_cast(I.getInsertedValueOperand()); - if (!InsertedC) - InsertedC = SimplifiedValues.lookup(I.getInsertedValueOperand()); - if (AggC && InsertedC) { - SimplifiedValues[&I] = ConstantExpr::getInsertValue(AggC, InsertedC, - I.getIndices()); - return true; - } - - // SROA can look through these but give them a cost. - return false; -} - -/// \brief Try to simplify a call site. -/// -/// Takes a concrete function and callsite and tries to actually simplify it by -/// analyzing the arguments and call itself with instsimplify. Returns true if -/// it has simplified the callsite to some other entity (a constant), making it -/// free. -bool CallAnalyzer::simplifyCallSite(Function *F, CallSite CS) { - // FIXME: Using the instsimplify logic directly for this is inefficient - // because we have to continually rebuild the argument list even when no - // simplifications can be performed. Until that is fixed with remapping - // inside of instsimplify, directly constant fold calls here. - if (!canConstantFoldCallTo(F)) - return false; - - // Try to re-map the arguments to constants. - SmallVector ConstantArgs; - ConstantArgs.reserve(CS.arg_size()); - for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); - I != E; ++I) { - Constant *C = dyn_cast(*I); - if (!C) - C = dyn_cast_or_null(SimplifiedValues.lookup(*I)); - if (!C) - return false; // This argument doesn't map to a constant. - - ConstantArgs.push_back(C); - } - if (Constant *C = ConstantFoldCall(F, ConstantArgs)) { - SimplifiedValues[CS.getInstruction()] = C; - return true; - } - - return false; -} - -bool CallAnalyzer::visitCallSite(CallSite CS) { - if (CS.hasFnAttr(Attribute::ReturnsTwice) && - !F.hasFnAttribute(Attribute::ReturnsTwice)) { - // This aborts the entire analysis. - ExposesReturnsTwice = true; - return false; - } - if (CS.isCall() && - cast(CS.getInstruction())->cannotDuplicate()) - ContainsNoDuplicateCall = true; - - if (Function *F = CS.getCalledFunction()) { - // When we have a concrete function, first try to simplify it directly. - if (simplifyCallSite(F, CS)) - return true; - - // Next check if it is an intrinsic we know about. - // FIXME: Lift this into part of the InstVisitor. - if (IntrinsicInst *II = dyn_cast(CS.getInstruction())) { - switch (II->getIntrinsicID()) { - default: - return Base::visitCallSite(CS); - - case Intrinsic::memset: - case Intrinsic::memcpy: - case Intrinsic::memmove: - // SROA can usually chew through these intrinsics, but they aren't free. - return false; - case Intrinsic::localescape: - HasFrameEscape = true; - return false; - } - } - - if (F == CS.getInstruction()->getParent()->getParent()) { - // This flag will fully abort the analysis, so don't bother with anything - // else. - IsRecursiveCall = true; - return false; - } - - if (TTI.isLoweredToCall(F)) { - // We account for the average 1 instruction per call argument setup - // here. - Cost += CS.arg_size() * InlineConstants::InstrCost; - - // Everything other than inline ASM will also have a significant cost - // merely from making the call. - if (!isa(CS.getCalledValue())) - Cost += InlineConstants::CallPenalty; - } - - return Base::visitCallSite(CS); - } - - // Otherwise we're in a very special case -- an indirect function call. See - // if we can be particularly clever about this. - Value *Callee = CS.getCalledValue(); - - // First, pay the price of the argument setup. We account for the average - // 1 instruction per call argument setup here. - Cost += CS.arg_size() * InlineConstants::InstrCost; - - // Next, check if this happens to be an indirect function call to a known - // function in this inline context. If not, we've done all we can. - Function *F = dyn_cast_or_null(SimplifiedValues.lookup(Callee)); - if (!F) - return Base::visitCallSite(CS); - - // If we have a constant that we are calling as a function, we can peer - // through it and see the function target. This happens not infrequently - // during devirtualization and so we want to give it a hefty bonus for - // inlining, but cap that bonus in the event that inlining wouldn't pan - // out. Pretend to inline the function, with a custom threshold. - CallAnalyzer CA(TTI, ACT, *F, InlineConstants::IndirectCallThreshold, CS); - if (CA.analyzeCall(CS)) { - // We were able to inline the indirect call! Subtract the cost from the - // bonus we want to apply, but don't go below zero. - Cost -= std::max(0, InlineConstants::IndirectCallThreshold - CA.getCost()); - } - - return Base::visitCallSite(CS); -} - -bool CallAnalyzer::visitReturnInst(ReturnInst &RI) { - // At least one return instruction will be free after inlining. - bool Free = !HasReturn; - HasReturn = true; - return Free; -} - -bool CallAnalyzer::visitBranchInst(BranchInst &BI) { - // We model unconditional branches as essentially free -- they really - // shouldn't exist at all, but handling them makes the behavior of the - // inliner more regular and predictable. Interestingly, conditional branches - // which will fold away are also free. - return BI.isUnconditional() || isa(BI.getCondition()) || - dyn_cast_or_null( - SimplifiedValues.lookup(BI.getCondition())); -} - -bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) { - // We model unconditional switches as free, see the comments on handling - // branches. - if (isa(SI.getCondition())) - return true; - if (Value *V = SimplifiedValues.lookup(SI.getCondition())) - if (isa(V)) - return true; - - // Otherwise, we need to accumulate a cost proportional to the number of - // distinct successor blocks. This fan-out in the CFG cannot be represented - // for free even if we can represent the core switch as a jumptable that - // takes a single instruction. - // - // NB: We convert large switches which are just used to initialize large phi - // nodes to lookup tables instead in simplify-cfg, so this shouldn't prevent - // inlining those. It will prevent inlining in cases where the optimization - // does not (yet) fire. - SmallPtrSet SuccessorBlocks; - SuccessorBlocks.insert(SI.getDefaultDest()); - for (auto I = SI.case_begin(), E = SI.case_end(); I != E; ++I) - SuccessorBlocks.insert(I.getCaseSuccessor()); - // Add cost corresponding to the number of distinct destinations. The first - // we model as free because of fallthrough. - Cost += (SuccessorBlocks.size() - 1) * InlineConstants::InstrCost; - return false; -} - -bool CallAnalyzer::visitIndirectBrInst(IndirectBrInst &IBI) { - // We never want to inline functions that contain an indirectbr. This is - // incorrect because all the blockaddress's (in static global initializers - // for example) would be referring to the original function, and this - // indirect jump would jump from the inlined copy of the function into the - // original function which is extremely undefined behavior. - // FIXME: This logic isn't really right; we can safely inline functions with - // indirectbr's as long as no other function or global references the - // blockaddress of a block within the current function. - HasIndirectBr = true; - return false; -} - -bool CallAnalyzer::visitResumeInst(ResumeInst &RI) { - // FIXME: It's not clear that a single instruction is an accurate model for - // the inline cost of a resume instruction. - return false; -} - -bool CallAnalyzer::visitCleanupReturnInst(CleanupReturnInst &CRI) { - // FIXME: It's not clear that a single instruction is an accurate model for - // the inline cost of a cleanupret instruction. - return false; -} - -bool CallAnalyzer::visitCatchReturnInst(CatchReturnInst &CRI) { - // FIXME: It's not clear that a single instruction is an accurate model for - // the inline cost of a cleanupret instruction. - return false; -} - -bool CallAnalyzer::visitUnreachableInst(UnreachableInst &I) { - // FIXME: It might be reasonably to discount the cost of instructions leading - // to unreachable as they have the lowest possible impact on both runtime and - // code size. - return true; // No actual code is needed for unreachable. -} - -bool CallAnalyzer::visitInstruction(Instruction &I) { - // Some instructions are free. All of the free intrinsics can also be - // handled by SROA, etc. - if (TargetTransformInfo::TCC_Free == TTI.getUserCost(&I)) - return true; - - // We found something we don't understand or can't handle. Mark any SROA-able - // values in the operand list as no longer viable. - for (User::op_iterator OI = I.op_begin(), OE = I.op_end(); OI != OE; ++OI) - disableSROA(*OI); - - return false; -} - - -/// \brief Analyze a basic block for its contribution to the inline cost. -/// -/// This method walks the analyzer over every instruction in the given basic -/// block and accounts for their cost during inlining at this callsite. It -/// aborts early if the threshold has been exceeded or an impossible to inline -/// construct has been detected. It returns false if inlining is no longer -/// viable, and true if inlining remains viable. -bool CallAnalyzer::analyzeBlock(BasicBlock *BB, - SmallPtrSetImpl &EphValues) { - for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { - // FIXME: Currently, the number of instructions in a function regardless of - // our ability to simplify them during inline to constants or dead code, - // are actually used by the vector bonus heuristic. As long as that's true, - // we have to special case debug intrinsics here to prevent differences in - // inlining due to debug symbols. Eventually, the number of unsimplified - // instructions shouldn't factor into the cost computation, but until then, - // hack around it here. - if (isa(I)) - continue; - - // Skip ephemeral values. - if (EphValues.count(I)) - continue; - - ++NumInstructions; - if (isa(I) || I->getType()->isVectorTy()) - ++NumVectorInstructions; - - // If the instruction is floating point, and the target says this operation is - // expensive or the function has the "use-soft-float" attribute, this may - // eventually become a library call. Treat the cost as such. - if (I->getType()->isFloatingPointTy()) { - bool hasSoftFloatAttr = false; - - // If the function has the "use-soft-float" attribute, mark it as expensive. - if (F.hasFnAttribute("use-soft-float")) { - Attribute Attr = F.getFnAttribute("use-soft-float"); - StringRef Val = Attr.getValueAsString(); - if (Val == "true") - hasSoftFloatAttr = true; - } - - if (TTI.getFPOpCost(I->getType()) == TargetTransformInfo::TCC_Expensive || - hasSoftFloatAttr) - Cost += InlineConstants::CallPenalty; - } - - // If the instruction simplified to a constant, there is no cost to this - // instruction. Visit the instructions using our InstVisitor to account for - // all of the per-instruction logic. The visit tree returns true if we - // consumed the instruction in any way, and false if the instruction's base - // cost should count against inlining. - if (Base::visit(I)) - ++NumInstructionsSimplified; - else - Cost += InlineConstants::InstrCost; - - // If the visit this instruction detected an uninlinable pattern, abort. - if (IsRecursiveCall || ExposesReturnsTwice || HasDynamicAlloca || - HasIndirectBr || HasFrameEscape) - return false; - - // If the caller is a recursive function then we don't want to inline - // functions which allocate a lot of stack space because it would increase - // the caller stack usage dramatically. - if (IsCallerRecursive && - AllocatedSize > InlineConstants::TotalAllocaSizeRecursiveCaller) - return false; - - // Check if we've past the maximum possible threshold so we don't spin in - // huge basic blocks that will never inline. - if (Cost > Threshold) - return false; - } - - return true; -} - -/// \brief Compute the base pointer and cumulative constant offsets for V. -/// -/// This strips all constant offsets off of V, leaving it the base pointer, and -/// accumulates the total constant offset applied in the returned constant. It -/// returns 0 if V is not a pointer, and returns the constant '0' if there are -/// no constant offsets applied. -ConstantInt *CallAnalyzer::stripAndComputeInBoundsConstantOffsets(Value *&V) { - if (!V->getType()->isPointerTy()) - return nullptr; - - const DataLayout &DL = F.getParent()->getDataLayout(); - unsigned IntPtrWidth = DL.getPointerSizeInBits(); - APInt Offset = APInt::getNullValue(IntPtrWidth); - - // Even though we don't look through PHI nodes, we could be called on an - // instruction in an unreachable block, which may be on a cycle. - SmallPtrSet Visited; - Visited.insert(V); - do { - if (GEPOperator *GEP = dyn_cast(V)) { - if (!GEP->isInBounds() || !accumulateGEPOffset(*GEP, Offset)) - return nullptr; - V = GEP->getPointerOperand(); - } else if (Operator::getOpcode(V) == Instruction::BitCast) { - V = cast(V)->getOperand(0); - } else if (GlobalAlias *GA = dyn_cast(V)) { - if (GA->mayBeOverridden()) - break; - V = GA->getAliasee(); - } else { - break; - } - assert(V->getType()->isPointerTy() && "Unexpected operand type!"); - } while (Visited.insert(V).second); - - Type *IntPtrTy = DL.getIntPtrType(V->getContext()); - return cast(ConstantInt::get(IntPtrTy, Offset)); -} - -/// \brief Analyze a call site for potential inlining. -/// -/// Returns true if inlining this call is viable, and false if it is not -/// viable. It computes the cost and adjusts the threshold based on numerous -/// factors and heuristics. If this method returns false but the computed cost -/// is below the computed threshold, then inlining was forcibly disabled by -/// some artifact of the routine. -bool CallAnalyzer::analyzeCall(CallSite CS) { - ++NumCallsAnalyzed; - - // Perform some tweaks to the cost and threshold based on the direct - // callsite information. - - // We want to more aggressively inline vector-dense kernels, so up the - // threshold, and we'll lower it if the % of vector instructions gets too - // low. Note that these bonuses are some what arbitrary and evolved over time - // by accident as much as because they are principled bonuses. - // - // FIXME: It would be nice to remove all such bonuses. At least it would be - // nice to base the bonus values on something more scientific. - assert(NumInstructions == 0); - assert(NumVectorInstructions == 0); - FiftyPercentVectorBonus = 3 * Threshold / 2; - TenPercentVectorBonus = 3 * Threshold / 4; - const DataLayout &DL = F.getParent()->getDataLayout(); - - // Track whether the post-inlining function would have more than one basic - // block. A single basic block is often intended for inlining. Balloon the - // threshold by 50% until we pass the single-BB phase. - bool SingleBB = true; - int SingleBBBonus = Threshold / 2; - - // Speculatively apply all possible bonuses to Threshold. If cost exceeds - // this Threshold any time, and cost cannot decrease, we can stop processing - // the rest of the function body. - Threshold += (SingleBBBonus + FiftyPercentVectorBonus); - - // Give out bonuses per argument, as the instructions setting them up will - // be gone after inlining. - for (unsigned I = 0, E = CS.arg_size(); I != E; ++I) { - if (CS.isByValArgument(I)) { - // We approximate the number of loads and stores needed by dividing the - // size of the byval type by the target's pointer size. - PointerType *PTy = cast(CS.getArgument(I)->getType()); - unsigned TypeSize = DL.getTypeSizeInBits(PTy->getElementType()); - unsigned PointerSize = DL.getPointerSizeInBits(); - // Ceiling division. - unsigned NumStores = (TypeSize + PointerSize - 1) / PointerSize; - - // If it generates more than 8 stores it is likely to be expanded as an - // inline memcpy so we take that as an upper bound. Otherwise we assume - // one load and one store per word copied. - // FIXME: The maxStoresPerMemcpy setting from the target should be used - // here instead of a magic number of 8, but it's not available via - // DataLayout. - NumStores = std::min(NumStores, 8U); - - Cost -= 2 * NumStores * InlineConstants::InstrCost; - } else { - // For non-byval arguments subtract off one instruction per call - // argument. - Cost -= InlineConstants::InstrCost; - } - } - - // If there is only one call of the function, and it has internal linkage, - // the cost of inlining it drops dramatically. - bool OnlyOneCallAndLocalLinkage = F.hasLocalLinkage() && F.hasOneUse() && - &F == CS.getCalledFunction(); - if (OnlyOneCallAndLocalLinkage) - Cost += InlineConstants::LastCallToStaticBonus; - - // If the instruction after the call, or if the normal destination of the - // invoke is an unreachable instruction, the function is noreturn. As such, - // there is little point in inlining this unless there is literally zero - // cost. - Instruction *Instr = CS.getInstruction(); - if (InvokeInst *II = dyn_cast(Instr)) { - if (isa(II->getNormalDest()->begin())) - Threshold = 0; - } else if (isa(++BasicBlock::iterator(Instr))) - Threshold = 0; - - // If this function uses the coldcc calling convention, prefer not to inline - // it. - if (F.getCallingConv() == CallingConv::Cold) - Cost += InlineConstants::ColdccPenalty; - - // Check if we're done. This can happen due to bonuses and penalties. - if (Cost > Threshold) - return false; - - if (F.empty()) - return true; - - Function *Caller = CS.getInstruction()->getParent()->getParent(); - // Check if the caller function is recursive itself. - for (User *U : Caller->users()) { - CallSite Site(U); - if (!Site) - continue; - Instruction *I = Site.getInstruction(); - if (I->getParent()->getParent() == Caller) { - IsCallerRecursive = true; - break; - } - } - - // Populate our simplified values by mapping from function arguments to call - // arguments with known important simplifications. - CallSite::arg_iterator CAI = CS.arg_begin(); - for (Function::arg_iterator FAI = F.arg_begin(), FAE = F.arg_end(); - FAI != FAE; ++FAI, ++CAI) { - assert(CAI != CS.arg_end()); - if (Constant *C = dyn_cast(CAI)) - SimplifiedValues[FAI] = C; - - Value *PtrArg = *CAI; - if (ConstantInt *C = stripAndComputeInBoundsConstantOffsets(PtrArg)) { - ConstantOffsetPtrs[FAI] = std::make_pair(PtrArg, C->getValue()); - - // We can SROA any pointer arguments derived from alloca instructions. - if (isa(PtrArg)) { - SROAArgValues[FAI] = PtrArg; - SROAArgCosts[PtrArg] = 0; - } - } - } - NumConstantArgs = SimplifiedValues.size(); - NumConstantOffsetPtrArgs = ConstantOffsetPtrs.size(); - NumAllocaArgs = SROAArgValues.size(); - - // FIXME: If a caller has multiple calls to a callee, we end up recomputing - // the ephemeral values multiple times (and they're completely determined by - // the callee, so this is purely duplicate work). - SmallPtrSet EphValues; - CodeMetrics::collectEphemeralValues(&F, &ACT->getAssumptionCache(F), EphValues); - - // The worklist of live basic blocks in the callee *after* inlining. We avoid - // adding basic blocks of the callee which can be proven to be dead for this - // particular call site in order to get more accurate cost estimates. This - // requires a somewhat heavyweight iteration pattern: we need to walk the - // basic blocks in a breadth-first order as we insert live successors. To - // accomplish this, prioritizing for small iterations because we exit after - // crossing our threshold, we use a small-size optimized SetVector. - typedef SetVector, - SmallPtrSet > BBSetVector; - BBSetVector BBWorklist; - BBWorklist.insert(&F.getEntryBlock()); - // Note that we *must not* cache the size, this loop grows the worklist. - for (unsigned Idx = 0; Idx != BBWorklist.size(); ++Idx) { - // Bail out the moment we cross the threshold. This means we'll under-count - // the cost, but only when undercounting doesn't matter. - if (Cost > Threshold) - break; - - BasicBlock *BB = BBWorklist[Idx]; - if (BB->empty()) - continue; - - // Disallow inlining a blockaddress. A blockaddress only has defined - // behavior for an indirect branch in the same function, and we do not - // currently support inlining indirect branches. But, the inliner may not - // see an indirect branch that ends up being dead code at a particular call - // site. If the blockaddress escapes the function, e.g., via a global - // variable, inlining may lead to an invalid cross-function reference. - if (BB->hasAddressTaken()) - return false; - - // Analyze the cost of this block. If we blow through the threshold, this - // returns false, and we can bail on out. - if (!analyzeBlock(BB, EphValues)) { - if (IsRecursiveCall || ExposesReturnsTwice || HasDynamicAlloca || - HasIndirectBr || HasFrameEscape) - return false; - - // If the caller is a recursive function then we don't want to inline - // functions which allocate a lot of stack space because it would increase - // the caller stack usage dramatically. - if (IsCallerRecursive && - AllocatedSize > InlineConstants::TotalAllocaSizeRecursiveCaller) - return false; - - break; - } - - TerminatorInst *TI = BB->getTerminator(); - - // Add in the live successors by first checking whether we have terminator - // that may be simplified based on the values simplified by this call. - if (BranchInst *BI = dyn_cast(TI)) { - if (BI->isConditional()) { - Value *Cond = BI->getCondition(); - if (ConstantInt *SimpleCond - = dyn_cast_or_null(SimplifiedValues.lookup(Cond))) { - BBWorklist.insert(BI->getSuccessor(SimpleCond->isZero() ? 1 : 0)); - continue; - } - } - } else if (SwitchInst *SI = dyn_cast(TI)) { - Value *Cond = SI->getCondition(); - if (ConstantInt *SimpleCond - = dyn_cast_or_null(SimplifiedValues.lookup(Cond))) { - BBWorklist.insert(SI->findCaseValue(SimpleCond).getCaseSuccessor()); - continue; - } - } - - // If we're unable to select a particular successor, just count all of - // them. - for (unsigned TIdx = 0, TSize = TI->getNumSuccessors(); TIdx != TSize; - ++TIdx) - BBWorklist.insert(TI->getSuccessor(TIdx)); - - // If we had any successors at this point, than post-inlining is likely to - // have them as well. Note that we assume any basic blocks which existed - // due to branches or switches which folded above will also fold after - // inlining. - if (SingleBB && TI->getNumSuccessors() > 1) { - // Take off the bonus we applied to the threshold. - Threshold -= SingleBBBonus; - SingleBB = false; - } - } - - // If this is a noduplicate call, we can still inline as long as - // inlining this would cause the removal of the caller (so the instruction - // is not actually duplicated, just moved). - if (!OnlyOneCallAndLocalLinkage && ContainsNoDuplicateCall) - return false; - - // We applied the maximum possible vector bonus at the beginning. Now, - // subtract the excess bonus, if any, from the Threshold before - // comparing against Cost. - if (NumVectorInstructions <= NumInstructions / 10) - Threshold -= FiftyPercentVectorBonus; - else if (NumVectorInstructions <= NumInstructions / 2) - Threshold -= (FiftyPercentVectorBonus - TenPercentVectorBonus); - - return Cost < Threshold; -} - -#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) -/// \brief Dump stats about this call's analysis. -void CallAnalyzer::dump() { -#define DEBUG_PRINT_STAT(x) dbgs() << " " #x ": " << x << "\n" - DEBUG_PRINT_STAT(NumConstantArgs); - DEBUG_PRINT_STAT(NumConstantOffsetPtrArgs); - DEBUG_PRINT_STAT(NumAllocaArgs); - DEBUG_PRINT_STAT(NumConstantPtrCmps); - DEBUG_PRINT_STAT(NumConstantPtrDiffs); - DEBUG_PRINT_STAT(NumInstructionsSimplified); - DEBUG_PRINT_STAT(NumInstructions); - DEBUG_PRINT_STAT(SROACostSavings); - DEBUG_PRINT_STAT(SROACostSavingsLost); - DEBUG_PRINT_STAT(ContainsNoDuplicateCall); - DEBUG_PRINT_STAT(Cost); - DEBUG_PRINT_STAT(Threshold); -#undef DEBUG_PRINT_STAT -} -#endif - -INITIALIZE_PASS_BEGIN(InlineCostAnalysis, "inline-cost", "Inline Cost Analysis", - true, true) -INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass) -INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker) -INITIALIZE_PASS_END(InlineCostAnalysis, "inline-cost", "Inline Cost Analysis", - true, true) - -char InlineCostAnalysis::ID = 0; - -InlineCostAnalysis::InlineCostAnalysis() : CallGraphSCCPass(ID) {} - -InlineCostAnalysis::~InlineCostAnalysis() {} - -void InlineCostAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { - AU.setPreservesAll(); - AU.addRequired(); - AU.addRequired(); - CallGraphSCCPass::getAnalysisUsage(AU); -} - -bool InlineCostAnalysis::runOnSCC(CallGraphSCC &SCC) { - TTIWP = &getAnalysis(); - ACT = &getAnalysis(); - return false; -} - -InlineCost InlineCostAnalysis::getInlineCost(CallSite CS, int Threshold) { - return getInlineCost(CS, CS.getCalledFunction(), Threshold); -} - -/// \brief Test that two functions either have or have not the given attribute -/// at the same time. -template -static bool attributeMatches(Function *F1, Function *F2, AttrKind Attr) { - return F1->getFnAttribute(Attr) == F2->getFnAttribute(Attr); -} - -/// \brief Test that there are no attribute conflicts between Caller and Callee -/// that prevent inlining. -static bool functionsHaveCompatibleAttributes(Function *Caller, - Function *Callee, - TargetTransformInfo &TTI) { - return TTI.areInlineCompatible(Caller, Callee) && - attributeMatches(Caller, Callee, Attribute::SanitizeAddress) && - attributeMatches(Caller, Callee, Attribute::SanitizeMemory) && - attributeMatches(Caller, Callee, Attribute::SanitizeThread); -} - -InlineCost InlineCostAnalysis::getInlineCost(CallSite CS, Function *Callee, - int Threshold) { - // Cannot inline indirect calls. - if (!Callee) - return llvm::InlineCost::getNever(); - - // Calls to functions with always-inline attributes should be inlined - // whenever possible. - if (CS.hasFnAttr(Attribute::AlwaysInline)) { - if (isInlineViable(*Callee)) - return llvm::InlineCost::getAlways(); - return llvm::InlineCost::getNever(); - } - - // Never inline functions with conflicting attributes (unless callee has - // always-inline attribute). - if (!functionsHaveCompatibleAttributes(CS.getCaller(), Callee, - TTIWP->getTTI(*Callee))) - return llvm::InlineCost::getNever(); - - // Don't inline this call if the caller has the optnone attribute. - if (CS.getCaller()->hasFnAttribute(Attribute::OptimizeNone)) - return llvm::InlineCost::getNever(); - - // Don't inline functions which can be redefined at link-time to mean - // something else. Don't inline functions marked noinline or call sites - // marked noinline. - if (Callee->mayBeOverridden() || - Callee->hasFnAttribute(Attribute::NoInline) || CS.isNoInline()) - return llvm::InlineCost::getNever(); - - DEBUG(llvm::dbgs() << " Analyzing call of " << Callee->getName() - << "...\n"); - - CallAnalyzer CA(TTIWP->getTTI(*Callee), ACT, *Callee, Threshold, CS); - bool ShouldInline = CA.analyzeCall(CS); - - DEBUG(CA.dump()); - - // Check if there was a reason to force inlining or no inlining. - if (!ShouldInline && CA.getCost() < CA.getThreshold()) - return InlineCost::getNever(); - if (ShouldInline && CA.getCost() >= CA.getThreshold()) - return InlineCost::getAlways(); - - return llvm::InlineCost::get(CA.getCost(), CA.getThreshold()); -} - -bool InlineCostAnalysis::isInlineViable(Function &F) { - bool ReturnsTwice = F.hasFnAttribute(Attribute::ReturnsTwice); - for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) { - // Disallow inlining of functions which contain indirect branches or - // blockaddresses. - if (isa(BI->getTerminator()) || BI->hasAddressTaken()) - return false; - - for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE; - ++II) { - CallSite CS(II); - if (!CS) - continue; - - // Disallow recursive calls. - if (&F == CS.getCalledFunction()) - return false; - - // Disallow calls which expose returns-twice to a function not previously - // attributed as such. - if (!ReturnsTwice && CS.isCall() && - cast(CS.getInstruction())->canReturnTwice()) - return false; - - // Disallow inlining functions that call @llvm.localescape. Doing this - // correctly would require major changes to the inliner. - if (CS.getCalledFunction() && - CS.getCalledFunction()->getIntrinsicID() == - llvm::Intrinsic::localescape) - return false; - } - } - - return true; -} Index: llvm/trunk/lib/Analysis/IPA/LLVMBuild.txt =================================================================== --- llvm/trunk/lib/Analysis/IPA/LLVMBuild.txt +++ llvm/trunk/lib/Analysis/IPA/LLVMBuild.txt @@ -1,23 +0,0 @@ -;===- ./lib/Analysis/IPA/LLVMBuild.txt -------------------------*- Conf -*--===; -; -; The LLVM Compiler Infrastructure -; -; This file is distributed under the University of Illinois Open Source -; License. See LICENSE.TXT for details. -; -;===------------------------------------------------------------------------===; -; -; This is an LLVMBuild description file for the components in this subdirectory. -; -; For more information on the LLVMBuild system, please see: -; -; http://llvm.org/docs/LLVMBuild.html -; -;===------------------------------------------------------------------------===; - -[component_0] -type = Library -name = IPA -parent = Libraries -library_name = ipa -required_libraries = Analysis Core Support Index: llvm/trunk/lib/Analysis/IPA/Makefile =================================================================== --- llvm/trunk/lib/Analysis/IPA/Makefile +++ llvm/trunk/lib/Analysis/IPA/Makefile @@ -1,15 +0,0 @@ -##===- lib/Analysis/IPA/Makefile ---------------------------*- Makefile -*-===## -# -# The LLVM Compiler Infrastructure -# -# This file is distributed under the University of Illinois Open Source -# License. See LICENSE.TXT for details. -# -##===----------------------------------------------------------------------===## - -LEVEL = ../../.. -LIBRARYNAME = LLVMipa -BUILD_ARCHIVE = 1 - -include $(LEVEL)/Makefile.common - Index: llvm/trunk/lib/Analysis/InlineCost.cpp =================================================================== --- llvm/trunk/lib/Analysis/InlineCost.cpp +++ llvm/trunk/lib/Analysis/InlineCost.cpp @@ -0,0 +1,1451 @@ +//===- InlineCost.cpp - Cost analysis for inliner -------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements inline cost analysis. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Analysis/InlineCost.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SetVector.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/Analysis/AssumptionCache.h" +#include "llvm/Analysis/CodeMetrics.h" +#include "llvm/Analysis/ConstantFolding.h" +#include "llvm/Analysis/InstructionSimplify.h" +#include "llvm/Analysis/TargetTransformInfo.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/CallingConv.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/GetElementPtrTypeIterator.h" +#include "llvm/IR/GlobalAlias.h" +#include "llvm/IR/InstVisitor.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/Operator.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" + +using namespace llvm; + +#define DEBUG_TYPE "inline-cost" + +STATISTIC(NumCallsAnalyzed, "Number of call sites analyzed"); + +namespace { + +class CallAnalyzer : public InstVisitor { + typedef InstVisitor Base; + friend class InstVisitor; + + /// The TargetTransformInfo available for this compilation. + const TargetTransformInfo &TTI; + + /// The cache of @llvm.assume intrinsics. + AssumptionCacheTracker *ACT; + + // The called function. + Function &F; + + // The candidate callsite being analyzed. Please do not use this to do + // analysis in the caller function; we want the inline cost query to be + // easily cacheable. Instead, use the cover function paramHasAttr. + CallSite CandidateCS; + + int Threshold; + int Cost; + + bool IsCallerRecursive; + bool IsRecursiveCall; + bool ExposesReturnsTwice; + bool HasDynamicAlloca; + bool ContainsNoDuplicateCall; + bool HasReturn; + bool HasIndirectBr; + bool HasFrameEscape; + + /// Number of bytes allocated statically by the callee. + uint64_t AllocatedSize; + unsigned NumInstructions, NumVectorInstructions; + int FiftyPercentVectorBonus, TenPercentVectorBonus; + int VectorBonus; + + // While we walk the potentially-inlined instructions, we build up and + // maintain a mapping of simplified values specific to this callsite. The + // idea is to propagate any special information we have about arguments to + // this call through the inlinable section of the function, and account for + // likely simplifications post-inlining. The most important aspect we track + // is CFG altering simplifications -- when we prove a basic block dead, that + // can cause dramatic shifts in the cost of inlining a function. + DenseMap SimplifiedValues; + + // Keep track of the values which map back (through function arguments) to + // allocas on the caller stack which could be simplified through SROA. + DenseMap SROAArgValues; + + // The mapping of caller Alloca values to their accumulated cost savings. If + // we have to disable SROA for one of the allocas, this tells us how much + // cost must be added. + DenseMap SROAArgCosts; + + // Keep track of values which map to a pointer base and constant offset. + DenseMap > ConstantOffsetPtrs; + + // Custom simplification helper routines. + bool isAllocaDerivedArg(Value *V); + bool lookupSROAArgAndCost(Value *V, Value *&Arg, + DenseMap::iterator &CostIt); + void disableSROA(DenseMap::iterator CostIt); + void disableSROA(Value *V); + void accumulateSROACost(DenseMap::iterator CostIt, + int InstructionCost); + bool isGEPOffsetConstant(GetElementPtrInst &GEP); + bool accumulateGEPOffset(GEPOperator &GEP, APInt &Offset); + bool simplifyCallSite(Function *F, CallSite CS); + ConstantInt *stripAndComputeInBoundsConstantOffsets(Value *&V); + + /// Return true if the given argument to the function being considered for + /// inlining has the given attribute set either at the call site or the + /// function declaration. Primarily used to inspect call site specific + /// attributes since these can be more precise than the ones on the callee + /// itself. + bool paramHasAttr(Argument *A, Attribute::AttrKind Attr); + + /// Return true if the given value is known non null within the callee if + /// inlined through this particular callsite. + bool isKnownNonNullInCallee(Value *V); + + // Custom analysis routines. + bool analyzeBlock(BasicBlock *BB, SmallPtrSetImpl &EphValues); + + // Disable several entry points to the visitor so we don't accidentally use + // them by declaring but not defining them here. + void visit(Module *); void visit(Module &); + void visit(Function *); void visit(Function &); + void visit(BasicBlock *); void visit(BasicBlock &); + + // Provide base case for our instruction visit. + bool visitInstruction(Instruction &I); + + // Our visit overrides. + bool visitAlloca(AllocaInst &I); + bool visitPHI(PHINode &I); + bool visitGetElementPtr(GetElementPtrInst &I); + bool visitBitCast(BitCastInst &I); + bool visitPtrToInt(PtrToIntInst &I); + bool visitIntToPtr(IntToPtrInst &I); + bool visitCastInst(CastInst &I); + bool visitUnaryInstruction(UnaryInstruction &I); + bool visitCmpInst(CmpInst &I); + bool visitSub(BinaryOperator &I); + bool visitBinaryOperator(BinaryOperator &I); + bool visitLoad(LoadInst &I); + bool visitStore(StoreInst &I); + bool visitExtractValue(ExtractValueInst &I); + bool visitInsertValue(InsertValueInst &I); + bool visitCallSite(CallSite CS); + bool visitReturnInst(ReturnInst &RI); + bool visitBranchInst(BranchInst &BI); + bool visitSwitchInst(SwitchInst &SI); + bool visitIndirectBrInst(IndirectBrInst &IBI); + bool visitResumeInst(ResumeInst &RI); + bool visitCleanupReturnInst(CleanupReturnInst &RI); + bool visitCatchReturnInst(CatchReturnInst &RI); + bool visitUnreachableInst(UnreachableInst &I); + +public: + CallAnalyzer(const TargetTransformInfo &TTI, AssumptionCacheTracker *ACT, + Function &Callee, int Threshold, CallSite CSArg) + : TTI(TTI), ACT(ACT), F(Callee), CandidateCS(CSArg), Threshold(Threshold), + Cost(0), IsCallerRecursive(false), IsRecursiveCall(false), + ExposesReturnsTwice(false), HasDynamicAlloca(false), + ContainsNoDuplicateCall(false), HasReturn(false), HasIndirectBr(false), + HasFrameEscape(false), AllocatedSize(0), NumInstructions(0), + NumVectorInstructions(0), FiftyPercentVectorBonus(0), + TenPercentVectorBonus(0), VectorBonus(0), NumConstantArgs(0), + NumConstantOffsetPtrArgs(0), NumAllocaArgs(0), NumConstantPtrCmps(0), + NumConstantPtrDiffs(0), NumInstructionsSimplified(0), + SROACostSavings(0), SROACostSavingsLost(0) {} + + bool analyzeCall(CallSite CS); + + int getThreshold() { return Threshold; } + int getCost() { return Cost; } + + // Keep a bunch of stats about the cost savings found so we can print them + // out when debugging. + unsigned NumConstantArgs; + unsigned NumConstantOffsetPtrArgs; + unsigned NumAllocaArgs; + unsigned NumConstantPtrCmps; + unsigned NumConstantPtrDiffs; + unsigned NumInstructionsSimplified; + unsigned SROACostSavings; + unsigned SROACostSavingsLost; + + void dump(); +}; + +} // namespace + +/// \brief Test whether the given value is an Alloca-derived function argument. +bool CallAnalyzer::isAllocaDerivedArg(Value *V) { + return SROAArgValues.count(V); +} + +/// \brief Lookup the SROA-candidate argument and cost iterator which V maps to. +/// Returns false if V does not map to a SROA-candidate. +bool CallAnalyzer::lookupSROAArgAndCost( + Value *V, Value *&Arg, DenseMap::iterator &CostIt) { + if (SROAArgValues.empty() || SROAArgCosts.empty()) + return false; + + DenseMap::iterator ArgIt = SROAArgValues.find(V); + if (ArgIt == SROAArgValues.end()) + return false; + + Arg = ArgIt->second; + CostIt = SROAArgCosts.find(Arg); + return CostIt != SROAArgCosts.end(); +} + +/// \brief Disable SROA for the candidate marked by this cost iterator. +/// +/// This marks the candidate as no longer viable for SROA, and adds the cost +/// savings associated with it back into the inline cost measurement. +void CallAnalyzer::disableSROA(DenseMap::iterator CostIt) { + // If we're no longer able to perform SROA we need to undo its cost savings + // and prevent subsequent analysis. + Cost += CostIt->second; + SROACostSavings -= CostIt->second; + SROACostSavingsLost += CostIt->second; + SROAArgCosts.erase(CostIt); +} + +/// \brief If 'V' maps to a SROA candidate, disable SROA for it. +void CallAnalyzer::disableSROA(Value *V) { + Value *SROAArg; + DenseMap::iterator CostIt; + if (lookupSROAArgAndCost(V, SROAArg, CostIt)) + disableSROA(CostIt); +} + +/// \brief Accumulate the given cost for a particular SROA candidate. +void CallAnalyzer::accumulateSROACost(DenseMap::iterator CostIt, + int InstructionCost) { + CostIt->second += InstructionCost; + SROACostSavings += InstructionCost; +} + +/// \brief Check whether a GEP's indices are all constant. +/// +/// Respects any simplified values known during the analysis of this callsite. +bool CallAnalyzer::isGEPOffsetConstant(GetElementPtrInst &GEP) { + for (User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); I != E; ++I) + if (!isa(*I) && !SimplifiedValues.lookup(*I)) + return false; + + return true; +} + +/// \brief Accumulate a constant GEP offset into an APInt if possible. +/// +/// Returns false if unable to compute the offset for any reason. Respects any +/// simplified values known during the analysis of this callsite. +bool CallAnalyzer::accumulateGEPOffset(GEPOperator &GEP, APInt &Offset) { + const DataLayout &DL = F.getParent()->getDataLayout(); + unsigned IntPtrWidth = DL.getPointerSizeInBits(); + assert(IntPtrWidth == Offset.getBitWidth()); + + for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP); + GTI != GTE; ++GTI) { + ConstantInt *OpC = dyn_cast(GTI.getOperand()); + if (!OpC) + if (Constant *SimpleOp = SimplifiedValues.lookup(GTI.getOperand())) + OpC = dyn_cast(SimpleOp); + if (!OpC) + return false; + if (OpC->isZero()) continue; + + // Handle a struct index, which adds its field offset to the pointer. + if (StructType *STy = dyn_cast(*GTI)) { + unsigned ElementIdx = OpC->getZExtValue(); + const StructLayout *SL = DL.getStructLayout(STy); + Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx)); + continue; + } + + APInt TypeSize(IntPtrWidth, DL.getTypeAllocSize(GTI.getIndexedType())); + Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize; + } + return true; +} + +bool CallAnalyzer::visitAlloca(AllocaInst &I) { + // Check whether inlining will turn a dynamic alloca into a static + // alloca, and handle that case. + if (I.isArrayAllocation()) { + if (Constant *Size = SimplifiedValues.lookup(I.getArraySize())) { + ConstantInt *AllocSize = dyn_cast(Size); + assert(AllocSize && "Allocation size not a constant int?"); + Type *Ty = I.getAllocatedType(); + AllocatedSize += Ty->getPrimitiveSizeInBits() * AllocSize->getZExtValue(); + return Base::visitAlloca(I); + } + } + + // Accumulate the allocated size. + if (I.isStaticAlloca()) { + const DataLayout &DL = F.getParent()->getDataLayout(); + Type *Ty = I.getAllocatedType(); + AllocatedSize += DL.getTypeAllocSize(Ty); + } + + // We will happily inline static alloca instructions. + if (I.isStaticAlloca()) + return Base::visitAlloca(I); + + // FIXME: This is overly conservative. Dynamic allocas are inefficient for + // a variety of reasons, and so we would like to not inline them into + // functions which don't currently have a dynamic alloca. This simply + // disables inlining altogether in the presence of a dynamic alloca. + HasDynamicAlloca = true; + return false; +} + +bool CallAnalyzer::visitPHI(PHINode &I) { + // FIXME: We should potentially be tracking values through phi nodes, + // especially when they collapse to a single value due to deleted CFG edges + // during inlining. + + // FIXME: We need to propagate SROA *disabling* through phi nodes, even + // though we don't want to propagate it's bonuses. The idea is to disable + // SROA if it *might* be used in an inappropriate manner. + + // Phi nodes are always zero-cost. + return true; +} + +bool CallAnalyzer::visitGetElementPtr(GetElementPtrInst &I) { + Value *SROAArg; + DenseMap::iterator CostIt; + bool SROACandidate = lookupSROAArgAndCost(I.getPointerOperand(), + SROAArg, CostIt); + + // Try to fold GEPs of constant-offset call site argument pointers. This + // requires target data and inbounds GEPs. + if (I.isInBounds()) { + // Check if we have a base + offset for the pointer. + Value *Ptr = I.getPointerOperand(); + std::pair BaseAndOffset = ConstantOffsetPtrs.lookup(Ptr); + if (BaseAndOffset.first) { + // Check if the offset of this GEP is constant, and if so accumulate it + // into Offset. + if (!accumulateGEPOffset(cast(I), BaseAndOffset.second)) { + // Non-constant GEPs aren't folded, and disable SROA. + if (SROACandidate) + disableSROA(CostIt); + return false; + } + + // Add the result as a new mapping to Base + Offset. + ConstantOffsetPtrs[&I] = BaseAndOffset; + + // Also handle SROA candidates here, we already know that the GEP is + // all-constant indexed. + if (SROACandidate) + SROAArgValues[&I] = SROAArg; + + return true; + } + } + + if (isGEPOffsetConstant(I)) { + if (SROACandidate) + SROAArgValues[&I] = SROAArg; + + // Constant GEPs are modeled as free. + return true; + } + + // Variable GEPs will require math and will disable SROA. + if (SROACandidate) + disableSROA(CostIt); + return false; +} + +bool CallAnalyzer::visitBitCast(BitCastInst &I) { + // Propagate constants through bitcasts. + Constant *COp = dyn_cast(I.getOperand(0)); + if (!COp) + COp = SimplifiedValues.lookup(I.getOperand(0)); + if (COp) + if (Constant *C = ConstantExpr::getBitCast(COp, I.getType())) { + SimplifiedValues[&I] = C; + return true; + } + + // Track base/offsets through casts + std::pair BaseAndOffset + = ConstantOffsetPtrs.lookup(I.getOperand(0)); + // Casts don't change the offset, just wrap it up. + if (BaseAndOffset.first) + ConstantOffsetPtrs[&I] = BaseAndOffset; + + // Also look for SROA candidates here. + Value *SROAArg; + DenseMap::iterator CostIt; + if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) + SROAArgValues[&I] = SROAArg; + + // Bitcasts are always zero cost. + return true; +} + +bool CallAnalyzer::visitPtrToInt(PtrToIntInst &I) { + // Propagate constants through ptrtoint. + Constant *COp = dyn_cast(I.getOperand(0)); + if (!COp) + COp = SimplifiedValues.lookup(I.getOperand(0)); + if (COp) + if (Constant *C = ConstantExpr::getPtrToInt(COp, I.getType())) { + SimplifiedValues[&I] = C; + return true; + } + + // Track base/offset pairs when converted to a plain integer provided the + // integer is large enough to represent the pointer. + unsigned IntegerSize = I.getType()->getScalarSizeInBits(); + const DataLayout &DL = F.getParent()->getDataLayout(); + if (IntegerSize >= DL.getPointerSizeInBits()) { + std::pair BaseAndOffset + = ConstantOffsetPtrs.lookup(I.getOperand(0)); + if (BaseAndOffset.first) + ConstantOffsetPtrs[&I] = BaseAndOffset; + } + + // This is really weird. Technically, ptrtoint will disable SROA. However, + // unless that ptrtoint is *used* somewhere in the live basic blocks after + // inlining, it will be nuked, and SROA should proceed. All of the uses which + // would block SROA would also block SROA if applied directly to a pointer, + // and so we can just add the integer in here. The only places where SROA is + // preserved either cannot fire on an integer, or won't in-and-of themselves + // disable SROA (ext) w/o some later use that we would see and disable. + Value *SROAArg; + DenseMap::iterator CostIt; + if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) + SROAArgValues[&I] = SROAArg; + + return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I); +} + +bool CallAnalyzer::visitIntToPtr(IntToPtrInst &I) { + // Propagate constants through ptrtoint. + Constant *COp = dyn_cast(I.getOperand(0)); + if (!COp) + COp = SimplifiedValues.lookup(I.getOperand(0)); + if (COp) + if (Constant *C = ConstantExpr::getIntToPtr(COp, I.getType())) { + SimplifiedValues[&I] = C; + return true; + } + + // Track base/offset pairs when round-tripped through a pointer without + // modifications provided the integer is not too large. + Value *Op = I.getOperand(0); + unsigned IntegerSize = Op->getType()->getScalarSizeInBits(); + const DataLayout &DL = F.getParent()->getDataLayout(); + if (IntegerSize <= DL.getPointerSizeInBits()) { + std::pair BaseAndOffset = ConstantOffsetPtrs.lookup(Op); + if (BaseAndOffset.first) + ConstantOffsetPtrs[&I] = BaseAndOffset; + } + + // "Propagate" SROA here in the same manner as we do for ptrtoint above. + Value *SROAArg; + DenseMap::iterator CostIt; + if (lookupSROAArgAndCost(Op, SROAArg, CostIt)) + SROAArgValues[&I] = SROAArg; + + return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I); +} + +bool CallAnalyzer::visitCastInst(CastInst &I) { + // Propagate constants through ptrtoint. + Constant *COp = dyn_cast(I.getOperand(0)); + if (!COp) + COp = SimplifiedValues.lookup(I.getOperand(0)); + if (COp) + if (Constant *C = ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) { + SimplifiedValues[&I] = C; + return true; + } + + // Disable SROA in the face of arbitrary casts we don't whitelist elsewhere. + disableSROA(I.getOperand(0)); + + return TargetTransformInfo::TCC_Free == TTI.getUserCost(&I); +} + +bool CallAnalyzer::visitUnaryInstruction(UnaryInstruction &I) { + Value *Operand = I.getOperand(0); + Constant *COp = dyn_cast(Operand); + if (!COp) + COp = SimplifiedValues.lookup(Operand); + if (COp) { + const DataLayout &DL = F.getParent()->getDataLayout(); + if (Constant *C = ConstantFoldInstOperands(I.getOpcode(), I.getType(), + COp, DL)) { + SimplifiedValues[&I] = C; + return true; + } + } + + // Disable any SROA on the argument to arbitrary unary operators. + disableSROA(Operand); + + return false; +} + +bool CallAnalyzer::paramHasAttr(Argument *A, Attribute::AttrKind Attr) { + unsigned ArgNo = A->getArgNo(); + return CandidateCS.paramHasAttr(ArgNo+1, Attr); +} + +bool CallAnalyzer::isKnownNonNullInCallee(Value *V) { + // Does the *call site* have the NonNull attribute set on an argument? We + // use the attribute on the call site to memoize any analysis done in the + // caller. This will also trip if the callee function has a non-null + // parameter attribute, but that's a less interesting case because hopefully + // the callee would already have been simplified based on that. + if (Argument *A = dyn_cast(V)) + if (paramHasAttr(A, Attribute::NonNull)) + return true; + + // Is this an alloca in the caller? This is distinct from the attribute case + // above because attributes aren't updated within the inliner itself and we + // always want to catch the alloca derived case. + if (isAllocaDerivedArg(V)) + // We can actually predict the result of comparisons between an + // alloca-derived value and null. Note that this fires regardless of + // SROA firing. + return true; + + return false; +} + +bool CallAnalyzer::visitCmpInst(CmpInst &I) { + Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); + // First try to handle simplified comparisons. + if (!isa(LHS)) + if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS)) + LHS = SimpleLHS; + if (!isa(RHS)) + if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) + RHS = SimpleRHS; + if (Constant *CLHS = dyn_cast(LHS)) { + if (Constant *CRHS = dyn_cast(RHS)) + if (Constant *C = ConstantExpr::getCompare(I.getPredicate(), CLHS, CRHS)) { + SimplifiedValues[&I] = C; + return true; + } + } + + if (I.getOpcode() == Instruction::FCmp) + return false; + + // Otherwise look for a comparison between constant offset pointers with + // a common base. + Value *LHSBase, *RHSBase; + APInt LHSOffset, RHSOffset; + std::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS); + if (LHSBase) { + std::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS); + if (RHSBase && LHSBase == RHSBase) { + // We have common bases, fold the icmp to a constant based on the + // offsets. + Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset); + Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset); + if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) { + SimplifiedValues[&I] = C; + ++NumConstantPtrCmps; + return true; + } + } + } + + // If the comparison is an equality comparison with null, we can simplify it + // if we know the value (argument) can't be null + if (I.isEquality() && isa(I.getOperand(1)) && + isKnownNonNullInCallee(I.getOperand(0))) { + bool IsNotEqual = I.getPredicate() == CmpInst::ICMP_NE; + SimplifiedValues[&I] = IsNotEqual ? ConstantInt::getTrue(I.getType()) + : ConstantInt::getFalse(I.getType()); + return true; + } + // Finally check for SROA candidates in comparisons. + Value *SROAArg; + DenseMap::iterator CostIt; + if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) { + if (isa(I.getOperand(1))) { + accumulateSROACost(CostIt, InlineConstants::InstrCost); + return true; + } + + disableSROA(CostIt); + } + + return false; +} + +bool CallAnalyzer::visitSub(BinaryOperator &I) { + // Try to handle a special case: we can fold computing the difference of two + // constant-related pointers. + Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); + Value *LHSBase, *RHSBase; + APInt LHSOffset, RHSOffset; + std::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS); + if (LHSBase) { + std::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS); + if (RHSBase && LHSBase == RHSBase) { + // We have common bases, fold the subtract to a constant based on the + // offsets. + Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset); + Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset); + if (Constant *C = ConstantExpr::getSub(CLHS, CRHS)) { + SimplifiedValues[&I] = C; + ++NumConstantPtrDiffs; + return true; + } + } + } + + // Otherwise, fall back to the generic logic for simplifying and handling + // instructions. + return Base::visitSub(I); +} + +bool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) { + Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); + const DataLayout &DL = F.getParent()->getDataLayout(); + if (!isa(LHS)) + if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS)) + LHS = SimpleLHS; + if (!isa(RHS)) + if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) + RHS = SimpleRHS; + Value *SimpleV = nullptr; + if (auto FI = dyn_cast(&I)) + SimpleV = + SimplifyFPBinOp(I.getOpcode(), LHS, RHS, FI->getFastMathFlags(), DL); + else + SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL); + + if (Constant *C = dyn_cast_or_null(SimpleV)) { + SimplifiedValues[&I] = C; + return true; + } + + // Disable any SROA on arguments to arbitrary, unsimplified binary operators. + disableSROA(LHS); + disableSROA(RHS); + + return false; +} + +bool CallAnalyzer::visitLoad(LoadInst &I) { + Value *SROAArg; + DenseMap::iterator CostIt; + if (lookupSROAArgAndCost(I.getPointerOperand(), SROAArg, CostIt)) { + if (I.isSimple()) { + accumulateSROACost(CostIt, InlineConstants::InstrCost); + return true; + } + + disableSROA(CostIt); + } + + return false; +} + +bool CallAnalyzer::visitStore(StoreInst &I) { + Value *SROAArg; + DenseMap::iterator CostIt; + if (lookupSROAArgAndCost(I.getPointerOperand(), SROAArg, CostIt)) { + if (I.isSimple()) { + accumulateSROACost(CostIt, InlineConstants::InstrCost); + return true; + } + + disableSROA(CostIt); + } + + return false; +} + +bool CallAnalyzer::visitExtractValue(ExtractValueInst &I) { + // Constant folding for extract value is trivial. + Constant *C = dyn_cast(I.getAggregateOperand()); + if (!C) + C = SimplifiedValues.lookup(I.getAggregateOperand()); + if (C) { + SimplifiedValues[&I] = ConstantExpr::getExtractValue(C, I.getIndices()); + return true; + } + + // SROA can look through these but give them a cost. + return false; +} + +bool CallAnalyzer::visitInsertValue(InsertValueInst &I) { + // Constant folding for insert value is trivial. + Constant *AggC = dyn_cast(I.getAggregateOperand()); + if (!AggC) + AggC = SimplifiedValues.lookup(I.getAggregateOperand()); + Constant *InsertedC = dyn_cast(I.getInsertedValueOperand()); + if (!InsertedC) + InsertedC = SimplifiedValues.lookup(I.getInsertedValueOperand()); + if (AggC && InsertedC) { + SimplifiedValues[&I] = ConstantExpr::getInsertValue(AggC, InsertedC, + I.getIndices()); + return true; + } + + // SROA can look through these but give them a cost. + return false; +} + +/// \brief Try to simplify a call site. +/// +/// Takes a concrete function and callsite and tries to actually simplify it by +/// analyzing the arguments and call itself with instsimplify. Returns true if +/// it has simplified the callsite to some other entity (a constant), making it +/// free. +bool CallAnalyzer::simplifyCallSite(Function *F, CallSite CS) { + // FIXME: Using the instsimplify logic directly for this is inefficient + // because we have to continually rebuild the argument list even when no + // simplifications can be performed. Until that is fixed with remapping + // inside of instsimplify, directly constant fold calls here. + if (!canConstantFoldCallTo(F)) + return false; + + // Try to re-map the arguments to constants. + SmallVector ConstantArgs; + ConstantArgs.reserve(CS.arg_size()); + for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); + I != E; ++I) { + Constant *C = dyn_cast(*I); + if (!C) + C = dyn_cast_or_null(SimplifiedValues.lookup(*I)); + if (!C) + return false; // This argument doesn't map to a constant. + + ConstantArgs.push_back(C); + } + if (Constant *C = ConstantFoldCall(F, ConstantArgs)) { + SimplifiedValues[CS.getInstruction()] = C; + return true; + } + + return false; +} + +bool CallAnalyzer::visitCallSite(CallSite CS) { + if (CS.hasFnAttr(Attribute::ReturnsTwice) && + !F.hasFnAttribute(Attribute::ReturnsTwice)) { + // This aborts the entire analysis. + ExposesReturnsTwice = true; + return false; + } + if (CS.isCall() && + cast(CS.getInstruction())->cannotDuplicate()) + ContainsNoDuplicateCall = true; + + if (Function *F = CS.getCalledFunction()) { + // When we have a concrete function, first try to simplify it directly. + if (simplifyCallSite(F, CS)) + return true; + + // Next check if it is an intrinsic we know about. + // FIXME: Lift this into part of the InstVisitor. + if (IntrinsicInst *II = dyn_cast(CS.getInstruction())) { + switch (II->getIntrinsicID()) { + default: + return Base::visitCallSite(CS); + + case Intrinsic::memset: + case Intrinsic::memcpy: + case Intrinsic::memmove: + // SROA can usually chew through these intrinsics, but they aren't free. + return false; + case Intrinsic::localescape: + HasFrameEscape = true; + return false; + } + } + + if (F == CS.getInstruction()->getParent()->getParent()) { + // This flag will fully abort the analysis, so don't bother with anything + // else. + IsRecursiveCall = true; + return false; + } + + if (TTI.isLoweredToCall(F)) { + // We account for the average 1 instruction per call argument setup + // here. + Cost += CS.arg_size() * InlineConstants::InstrCost; + + // Everything other than inline ASM will also have a significant cost + // merely from making the call. + if (!isa(CS.getCalledValue())) + Cost += InlineConstants::CallPenalty; + } + + return Base::visitCallSite(CS); + } + + // Otherwise we're in a very special case -- an indirect function call. See + // if we can be particularly clever about this. + Value *Callee = CS.getCalledValue(); + + // First, pay the price of the argument setup. We account for the average + // 1 instruction per call argument setup here. + Cost += CS.arg_size() * InlineConstants::InstrCost; + + // Next, check if this happens to be an indirect function call to a known + // function in this inline context. If not, we've done all we can. + Function *F = dyn_cast_or_null(SimplifiedValues.lookup(Callee)); + if (!F) + return Base::visitCallSite(CS); + + // If we have a constant that we are calling as a function, we can peer + // through it and see the function target. This happens not infrequently + // during devirtualization and so we want to give it a hefty bonus for + // inlining, but cap that bonus in the event that inlining wouldn't pan + // out. Pretend to inline the function, with a custom threshold. + CallAnalyzer CA(TTI, ACT, *F, InlineConstants::IndirectCallThreshold, CS); + if (CA.analyzeCall(CS)) { + // We were able to inline the indirect call! Subtract the cost from the + // bonus we want to apply, but don't go below zero. + Cost -= std::max(0, InlineConstants::IndirectCallThreshold - CA.getCost()); + } + + return Base::visitCallSite(CS); +} + +bool CallAnalyzer::visitReturnInst(ReturnInst &RI) { + // At least one return instruction will be free after inlining. + bool Free = !HasReturn; + HasReturn = true; + return Free; +} + +bool CallAnalyzer::visitBranchInst(BranchInst &BI) { + // We model unconditional branches as essentially free -- they really + // shouldn't exist at all, but handling them makes the behavior of the + // inliner more regular and predictable. Interestingly, conditional branches + // which will fold away are also free. + return BI.isUnconditional() || isa(BI.getCondition()) || + dyn_cast_or_null( + SimplifiedValues.lookup(BI.getCondition())); +} + +bool CallAnalyzer::visitSwitchInst(SwitchInst &SI) { + // We model unconditional switches as free, see the comments on handling + // branches. + if (isa(SI.getCondition())) + return true; + if (Value *V = SimplifiedValues.lookup(SI.getCondition())) + if (isa(V)) + return true; + + // Otherwise, we need to accumulate a cost proportional to the number of + // distinct successor blocks. This fan-out in the CFG cannot be represented + // for free even if we can represent the core switch as a jumptable that + // takes a single instruction. + // + // NB: We convert large switches which are just used to initialize large phi + // nodes to lookup tables instead in simplify-cfg, so this shouldn't prevent + // inlining those. It will prevent inlining in cases where the optimization + // does not (yet) fire. + SmallPtrSet SuccessorBlocks; + SuccessorBlocks.insert(SI.getDefaultDest()); + for (auto I = SI.case_begin(), E = SI.case_end(); I != E; ++I) + SuccessorBlocks.insert(I.getCaseSuccessor()); + // Add cost corresponding to the number of distinct destinations. The first + // we model as free because of fallthrough. + Cost += (SuccessorBlocks.size() - 1) * InlineConstants::InstrCost; + return false; +} + +bool CallAnalyzer::visitIndirectBrInst(IndirectBrInst &IBI) { + // We never want to inline functions that contain an indirectbr. This is + // incorrect because all the blockaddress's (in static global initializers + // for example) would be referring to the original function, and this + // indirect jump would jump from the inlined copy of the function into the + // original function which is extremely undefined behavior. + // FIXME: This logic isn't really right; we can safely inline functions with + // indirectbr's as long as no other function or global references the + // blockaddress of a block within the current function. + HasIndirectBr = true; + return false; +} + +bool CallAnalyzer::visitResumeInst(ResumeInst &RI) { + // FIXME: It's not clear that a single instruction is an accurate model for + // the inline cost of a resume instruction. + return false; +} + +bool CallAnalyzer::visitCleanupReturnInst(CleanupReturnInst &CRI) { + // FIXME: It's not clear that a single instruction is an accurate model for + // the inline cost of a cleanupret instruction. + return false; +} + +bool CallAnalyzer::visitCatchReturnInst(CatchReturnInst &CRI) { + // FIXME: It's not clear that a single instruction is an accurate model for + // the inline cost of a cleanupret instruction. + return false; +} + +bool CallAnalyzer::visitUnreachableInst(UnreachableInst &I) { + // FIXME: It might be reasonably to discount the cost of instructions leading + // to unreachable as they have the lowest possible impact on both runtime and + // code size. + return true; // No actual code is needed for unreachable. +} + +bool CallAnalyzer::visitInstruction(Instruction &I) { + // Some instructions are free. All of the free intrinsics can also be + // handled by SROA, etc. + if (TargetTransformInfo::TCC_Free == TTI.getUserCost(&I)) + return true; + + // We found something we don't understand or can't handle. Mark any SROA-able + // values in the operand list as no longer viable. + for (User::op_iterator OI = I.op_begin(), OE = I.op_end(); OI != OE; ++OI) + disableSROA(*OI); + + return false; +} + + +/// \brief Analyze a basic block for its contribution to the inline cost. +/// +/// This method walks the analyzer over every instruction in the given basic +/// block and accounts for their cost during inlining at this callsite. It +/// aborts early if the threshold has been exceeded or an impossible to inline +/// construct has been detected. It returns false if inlining is no longer +/// viable, and true if inlining remains viable. +bool CallAnalyzer::analyzeBlock(BasicBlock *BB, + SmallPtrSetImpl &EphValues) { + for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { + // FIXME: Currently, the number of instructions in a function regardless of + // our ability to simplify them during inline to constants or dead code, + // are actually used by the vector bonus heuristic. As long as that's true, + // we have to special case debug intrinsics here to prevent differences in + // inlining due to debug symbols. Eventually, the number of unsimplified + // instructions shouldn't factor into the cost computation, but until then, + // hack around it here. + if (isa(I)) + continue; + + // Skip ephemeral values. + if (EphValues.count(I)) + continue; + + ++NumInstructions; + if (isa(I) || I->getType()->isVectorTy()) + ++NumVectorInstructions; + + // If the instruction is floating point, and the target says this operation is + // expensive or the function has the "use-soft-float" attribute, this may + // eventually become a library call. Treat the cost as such. + if (I->getType()->isFloatingPointTy()) { + bool hasSoftFloatAttr = false; + + // If the function has the "use-soft-float" attribute, mark it as expensive. + if (F.hasFnAttribute("use-soft-float")) { + Attribute Attr = F.getFnAttribute("use-soft-float"); + StringRef Val = Attr.getValueAsString(); + if (Val == "true") + hasSoftFloatAttr = true; + } + + if (TTI.getFPOpCost(I->getType()) == TargetTransformInfo::TCC_Expensive || + hasSoftFloatAttr) + Cost += InlineConstants::CallPenalty; + } + + // If the instruction simplified to a constant, there is no cost to this + // instruction. Visit the instructions using our InstVisitor to account for + // all of the per-instruction logic. The visit tree returns true if we + // consumed the instruction in any way, and false if the instruction's base + // cost should count against inlining. + if (Base::visit(I)) + ++NumInstructionsSimplified; + else + Cost += InlineConstants::InstrCost; + + // If the visit this instruction detected an uninlinable pattern, abort. + if (IsRecursiveCall || ExposesReturnsTwice || HasDynamicAlloca || + HasIndirectBr || HasFrameEscape) + return false; + + // If the caller is a recursive function then we don't want to inline + // functions which allocate a lot of stack space because it would increase + // the caller stack usage dramatically. + if (IsCallerRecursive && + AllocatedSize > InlineConstants::TotalAllocaSizeRecursiveCaller) + return false; + + // Check if we've past the maximum possible threshold so we don't spin in + // huge basic blocks that will never inline. + if (Cost > Threshold) + return false; + } + + return true; +} + +/// \brief Compute the base pointer and cumulative constant offsets for V. +/// +/// This strips all constant offsets off of V, leaving it the base pointer, and +/// accumulates the total constant offset applied in the returned constant. It +/// returns 0 if V is not a pointer, and returns the constant '0' if there are +/// no constant offsets applied. +ConstantInt *CallAnalyzer::stripAndComputeInBoundsConstantOffsets(Value *&V) { + if (!V->getType()->isPointerTy()) + return nullptr; + + const DataLayout &DL = F.getParent()->getDataLayout(); + unsigned IntPtrWidth = DL.getPointerSizeInBits(); + APInt Offset = APInt::getNullValue(IntPtrWidth); + + // Even though we don't look through PHI nodes, we could be called on an + // instruction in an unreachable block, which may be on a cycle. + SmallPtrSet Visited; + Visited.insert(V); + do { + if (GEPOperator *GEP = dyn_cast(V)) { + if (!GEP->isInBounds() || !accumulateGEPOffset(*GEP, Offset)) + return nullptr; + V = GEP->getPointerOperand(); + } else if (Operator::getOpcode(V) == Instruction::BitCast) { + V = cast(V)->getOperand(0); + } else if (GlobalAlias *GA = dyn_cast(V)) { + if (GA->mayBeOverridden()) + break; + V = GA->getAliasee(); + } else { + break; + } + assert(V->getType()->isPointerTy() && "Unexpected operand type!"); + } while (Visited.insert(V).second); + + Type *IntPtrTy = DL.getIntPtrType(V->getContext()); + return cast(ConstantInt::get(IntPtrTy, Offset)); +} + +/// \brief Analyze a call site for potential inlining. +/// +/// Returns true if inlining this call is viable, and false if it is not +/// viable. It computes the cost and adjusts the threshold based on numerous +/// factors and heuristics. If this method returns false but the computed cost +/// is below the computed threshold, then inlining was forcibly disabled by +/// some artifact of the routine. +bool CallAnalyzer::analyzeCall(CallSite CS) { + ++NumCallsAnalyzed; + + // Perform some tweaks to the cost and threshold based on the direct + // callsite information. + + // We want to more aggressively inline vector-dense kernels, so up the + // threshold, and we'll lower it if the % of vector instructions gets too + // low. Note that these bonuses are some what arbitrary and evolved over time + // by accident as much as because they are principled bonuses. + // + // FIXME: It would be nice to remove all such bonuses. At least it would be + // nice to base the bonus values on something more scientific. + assert(NumInstructions == 0); + assert(NumVectorInstructions == 0); + FiftyPercentVectorBonus = 3 * Threshold / 2; + TenPercentVectorBonus = 3 * Threshold / 4; + const DataLayout &DL = F.getParent()->getDataLayout(); + + // Track whether the post-inlining function would have more than one basic + // block. A single basic block is often intended for inlining. Balloon the + // threshold by 50% until we pass the single-BB phase. + bool SingleBB = true; + int SingleBBBonus = Threshold / 2; + + // Speculatively apply all possible bonuses to Threshold. If cost exceeds + // this Threshold any time, and cost cannot decrease, we can stop processing + // the rest of the function body. + Threshold += (SingleBBBonus + FiftyPercentVectorBonus); + + // Give out bonuses per argument, as the instructions setting them up will + // be gone after inlining. + for (unsigned I = 0, E = CS.arg_size(); I != E; ++I) { + if (CS.isByValArgument(I)) { + // We approximate the number of loads and stores needed by dividing the + // size of the byval type by the target's pointer size. + PointerType *PTy = cast(CS.getArgument(I)->getType()); + unsigned TypeSize = DL.getTypeSizeInBits(PTy->getElementType()); + unsigned PointerSize = DL.getPointerSizeInBits(); + // Ceiling division. + unsigned NumStores = (TypeSize + PointerSize - 1) / PointerSize; + + // If it generates more than 8 stores it is likely to be expanded as an + // inline memcpy so we take that as an upper bound. Otherwise we assume + // one load and one store per word copied. + // FIXME: The maxStoresPerMemcpy setting from the target should be used + // here instead of a magic number of 8, but it's not available via + // DataLayout. + NumStores = std::min(NumStores, 8U); + + Cost -= 2 * NumStores * InlineConstants::InstrCost; + } else { + // For non-byval arguments subtract off one instruction per call + // argument. + Cost -= InlineConstants::InstrCost; + } + } + + // If there is only one call of the function, and it has internal linkage, + // the cost of inlining it drops dramatically. + bool OnlyOneCallAndLocalLinkage = F.hasLocalLinkage() && F.hasOneUse() && + &F == CS.getCalledFunction(); + if (OnlyOneCallAndLocalLinkage) + Cost += InlineConstants::LastCallToStaticBonus; + + // If the instruction after the call, or if the normal destination of the + // invoke is an unreachable instruction, the function is noreturn. As such, + // there is little point in inlining this unless there is literally zero + // cost. + Instruction *Instr = CS.getInstruction(); + if (InvokeInst *II = dyn_cast(Instr)) { + if (isa(II->getNormalDest()->begin())) + Threshold = 0; + } else if (isa(++BasicBlock::iterator(Instr))) + Threshold = 0; + + // If this function uses the coldcc calling convention, prefer not to inline + // it. + if (F.getCallingConv() == CallingConv::Cold) + Cost += InlineConstants::ColdccPenalty; + + // Check if we're done. This can happen due to bonuses and penalties. + if (Cost > Threshold) + return false; + + if (F.empty()) + return true; + + Function *Caller = CS.getInstruction()->getParent()->getParent(); + // Check if the caller function is recursive itself. + for (User *U : Caller->users()) { + CallSite Site(U); + if (!Site) + continue; + Instruction *I = Site.getInstruction(); + if (I->getParent()->getParent() == Caller) { + IsCallerRecursive = true; + break; + } + } + + // Populate our simplified values by mapping from function arguments to call + // arguments with known important simplifications. + CallSite::arg_iterator CAI = CS.arg_begin(); + for (Function::arg_iterator FAI = F.arg_begin(), FAE = F.arg_end(); + FAI != FAE; ++FAI, ++CAI) { + assert(CAI != CS.arg_end()); + if (Constant *C = dyn_cast(CAI)) + SimplifiedValues[FAI] = C; + + Value *PtrArg = *CAI; + if (ConstantInt *C = stripAndComputeInBoundsConstantOffsets(PtrArg)) { + ConstantOffsetPtrs[FAI] = std::make_pair(PtrArg, C->getValue()); + + // We can SROA any pointer arguments derived from alloca instructions. + if (isa(PtrArg)) { + SROAArgValues[FAI] = PtrArg; + SROAArgCosts[PtrArg] = 0; + } + } + } + NumConstantArgs = SimplifiedValues.size(); + NumConstantOffsetPtrArgs = ConstantOffsetPtrs.size(); + NumAllocaArgs = SROAArgValues.size(); + + // FIXME: If a caller has multiple calls to a callee, we end up recomputing + // the ephemeral values multiple times (and they're completely determined by + // the callee, so this is purely duplicate work). + SmallPtrSet EphValues; + CodeMetrics::collectEphemeralValues(&F, &ACT->getAssumptionCache(F), EphValues); + + // The worklist of live basic blocks in the callee *after* inlining. We avoid + // adding basic blocks of the callee which can be proven to be dead for this + // particular call site in order to get more accurate cost estimates. This + // requires a somewhat heavyweight iteration pattern: we need to walk the + // basic blocks in a breadth-first order as we insert live successors. To + // accomplish this, prioritizing for small iterations because we exit after + // crossing our threshold, we use a small-size optimized SetVector. + typedef SetVector, + SmallPtrSet > BBSetVector; + BBSetVector BBWorklist; + BBWorklist.insert(&F.getEntryBlock()); + // Note that we *must not* cache the size, this loop grows the worklist. + for (unsigned Idx = 0; Idx != BBWorklist.size(); ++Idx) { + // Bail out the moment we cross the threshold. This means we'll under-count + // the cost, but only when undercounting doesn't matter. + if (Cost > Threshold) + break; + + BasicBlock *BB = BBWorklist[Idx]; + if (BB->empty()) + continue; + + // Disallow inlining a blockaddress. A blockaddress only has defined + // behavior for an indirect branch in the same function, and we do not + // currently support inlining indirect branches. But, the inliner may not + // see an indirect branch that ends up being dead code at a particular call + // site. If the blockaddress escapes the function, e.g., via a global + // variable, inlining may lead to an invalid cross-function reference. + if (BB->hasAddressTaken()) + return false; + + // Analyze the cost of this block. If we blow through the threshold, this + // returns false, and we can bail on out. + if (!analyzeBlock(BB, EphValues)) { + if (IsRecursiveCall || ExposesReturnsTwice || HasDynamicAlloca || + HasIndirectBr || HasFrameEscape) + return false; + + // If the caller is a recursive function then we don't want to inline + // functions which allocate a lot of stack space because it would increase + // the caller stack usage dramatically. + if (IsCallerRecursive && + AllocatedSize > InlineConstants::TotalAllocaSizeRecursiveCaller) + return false; + + break; + } + + TerminatorInst *TI = BB->getTerminator(); + + // Add in the live successors by first checking whether we have terminator + // that may be simplified based on the values simplified by this call. + if (BranchInst *BI = dyn_cast(TI)) { + if (BI->isConditional()) { + Value *Cond = BI->getCondition(); + if (ConstantInt *SimpleCond + = dyn_cast_or_null(SimplifiedValues.lookup(Cond))) { + BBWorklist.insert(BI->getSuccessor(SimpleCond->isZero() ? 1 : 0)); + continue; + } + } + } else if (SwitchInst *SI = dyn_cast(TI)) { + Value *Cond = SI->getCondition(); + if (ConstantInt *SimpleCond + = dyn_cast_or_null(SimplifiedValues.lookup(Cond))) { + BBWorklist.insert(SI->findCaseValue(SimpleCond).getCaseSuccessor()); + continue; + } + } + + // If we're unable to select a particular successor, just count all of + // them. + for (unsigned TIdx = 0, TSize = TI->getNumSuccessors(); TIdx != TSize; + ++TIdx) + BBWorklist.insert(TI->getSuccessor(TIdx)); + + // If we had any successors at this point, than post-inlining is likely to + // have them as well. Note that we assume any basic blocks which existed + // due to branches or switches which folded above will also fold after + // inlining. + if (SingleBB && TI->getNumSuccessors() > 1) { + // Take off the bonus we applied to the threshold. + Threshold -= SingleBBBonus; + SingleBB = false; + } + } + + // If this is a noduplicate call, we can still inline as long as + // inlining this would cause the removal of the caller (so the instruction + // is not actually duplicated, just moved). + if (!OnlyOneCallAndLocalLinkage && ContainsNoDuplicateCall) + return false; + + // We applied the maximum possible vector bonus at the beginning. Now, + // subtract the excess bonus, if any, from the Threshold before + // comparing against Cost. + if (NumVectorInstructions <= NumInstructions / 10) + Threshold -= FiftyPercentVectorBonus; + else if (NumVectorInstructions <= NumInstructions / 2) + Threshold -= (FiftyPercentVectorBonus - TenPercentVectorBonus); + + return Cost < Threshold; +} + +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +/// \brief Dump stats about this call's analysis. +void CallAnalyzer::dump() { +#define DEBUG_PRINT_STAT(x) dbgs() << " " #x ": " << x << "\n" + DEBUG_PRINT_STAT(NumConstantArgs); + DEBUG_PRINT_STAT(NumConstantOffsetPtrArgs); + DEBUG_PRINT_STAT(NumAllocaArgs); + DEBUG_PRINT_STAT(NumConstantPtrCmps); + DEBUG_PRINT_STAT(NumConstantPtrDiffs); + DEBUG_PRINT_STAT(NumInstructionsSimplified); + DEBUG_PRINT_STAT(NumInstructions); + DEBUG_PRINT_STAT(SROACostSavings); + DEBUG_PRINT_STAT(SROACostSavingsLost); + DEBUG_PRINT_STAT(ContainsNoDuplicateCall); + DEBUG_PRINT_STAT(Cost); + DEBUG_PRINT_STAT(Threshold); +#undef DEBUG_PRINT_STAT +} +#endif + +INITIALIZE_PASS_BEGIN(InlineCostAnalysis, "inline-cost", "Inline Cost Analysis", + true, true) +INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass) +INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker) +INITIALIZE_PASS_END(InlineCostAnalysis, "inline-cost", "Inline Cost Analysis", + true, true) + +char InlineCostAnalysis::ID = 0; + +InlineCostAnalysis::InlineCostAnalysis() : CallGraphSCCPass(ID) {} + +InlineCostAnalysis::~InlineCostAnalysis() {} + +void InlineCostAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesAll(); + AU.addRequired(); + AU.addRequired(); + CallGraphSCCPass::getAnalysisUsage(AU); +} + +bool InlineCostAnalysis::runOnSCC(CallGraphSCC &SCC) { + TTIWP = &getAnalysis(); + ACT = &getAnalysis(); + return false; +} + +InlineCost InlineCostAnalysis::getInlineCost(CallSite CS, int Threshold) { + return getInlineCost(CS, CS.getCalledFunction(), Threshold); +} + +/// \brief Test that two functions either have or have not the given attribute +/// at the same time. +template +static bool attributeMatches(Function *F1, Function *F2, AttrKind Attr) { + return F1->getFnAttribute(Attr) == F2->getFnAttribute(Attr); +} + +/// \brief Test that there are no attribute conflicts between Caller and Callee +/// that prevent inlining. +static bool functionsHaveCompatibleAttributes(Function *Caller, + Function *Callee, + TargetTransformInfo &TTI) { + return TTI.areInlineCompatible(Caller, Callee) && + attributeMatches(Caller, Callee, Attribute::SanitizeAddress) && + attributeMatches(Caller, Callee, Attribute::SanitizeMemory) && + attributeMatches(Caller, Callee, Attribute::SanitizeThread); +} + +InlineCost InlineCostAnalysis::getInlineCost(CallSite CS, Function *Callee, + int Threshold) { + // Cannot inline indirect calls. + if (!Callee) + return llvm::InlineCost::getNever(); + + // Calls to functions with always-inline attributes should be inlined + // whenever possible. + if (CS.hasFnAttr(Attribute::AlwaysInline)) { + if (isInlineViable(*Callee)) + return llvm::InlineCost::getAlways(); + return llvm::InlineCost::getNever(); + } + + // Never inline functions with conflicting attributes (unless callee has + // always-inline attribute). + if (!functionsHaveCompatibleAttributes(CS.getCaller(), Callee, + TTIWP->getTTI(*Callee))) + return llvm::InlineCost::getNever(); + + // Don't inline this call if the caller has the optnone attribute. + if (CS.getCaller()->hasFnAttribute(Attribute::OptimizeNone)) + return llvm::InlineCost::getNever(); + + // Don't inline functions which can be redefined at link-time to mean + // something else. Don't inline functions marked noinline or call sites + // marked noinline. + if (Callee->mayBeOverridden() || + Callee->hasFnAttribute(Attribute::NoInline) || CS.isNoInline()) + return llvm::InlineCost::getNever(); + + DEBUG(llvm::dbgs() << " Analyzing call of " << Callee->getName() + << "...\n"); + + CallAnalyzer CA(TTIWP->getTTI(*Callee), ACT, *Callee, Threshold, CS); + bool ShouldInline = CA.analyzeCall(CS); + + DEBUG(CA.dump()); + + // Check if there was a reason to force inlining or no inlining. + if (!ShouldInline && CA.getCost() < CA.getThreshold()) + return InlineCost::getNever(); + if (ShouldInline && CA.getCost() >= CA.getThreshold()) + return InlineCost::getAlways(); + + return llvm::InlineCost::get(CA.getCost(), CA.getThreshold()); +} + +bool InlineCostAnalysis::isInlineViable(Function &F) { + bool ReturnsTwice = F.hasFnAttribute(Attribute::ReturnsTwice); + for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) { + // Disallow inlining of functions which contain indirect branches or + // blockaddresses. + if (isa(BI->getTerminator()) || BI->hasAddressTaken()) + return false; + + for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE; + ++II) { + CallSite CS(II); + if (!CS) + continue; + + // Disallow recursive calls. + if (&F == CS.getCalledFunction()) + return false; + + // Disallow calls which expose returns-twice to a function not previously + // attributed as such. + if (!ReturnsTwice && CS.isCall() && + cast(CS.getInstruction())->canReturnTwice()) + return false; + + // Disallow inlining functions that call @llvm.localescape. Doing this + // correctly would require major changes to the inliner. + if (CS.getCalledFunction() && + CS.getCalledFunction()->getIntrinsicID() == + llvm::Intrinsic::localescape) + return false; + } + } + + return true; +} Index: llvm/trunk/lib/Analysis/LLVMBuild.txt =================================================================== --- llvm/trunk/lib/Analysis/LLVMBuild.txt +++ llvm/trunk/lib/Analysis/LLVMBuild.txt @@ -15,9 +15,6 @@ ; ;===------------------------------------------------------------------------===; -[common] -subdirectories = IPA - [component_0] type = Library name = Analysis Index: llvm/trunk/lib/Analysis/Makefile =================================================================== --- llvm/trunk/lib/Analysis/Makefile +++ llvm/trunk/lib/Analysis/Makefile @@ -9,7 +9,6 @@ LEVEL = ../.. LIBRARYNAME = LLVMAnalysis -DIRS = IPA BUILD_ARCHIVE = 1 include $(LEVEL)/Makefile.common Index: llvm/trunk/lib/LTO/LLVMBuild.txt =================================================================== --- llvm/trunk/lib/LTO/LLVMBuild.txt +++ llvm/trunk/lib/LTO/LLVMBuild.txt @@ -25,7 +25,6 @@ BitWriter CodeGen Core - IPA IPO InstCombine Linker Index: llvm/trunk/lib/Passes/LLVMBuild.txt =================================================================== --- llvm/trunk/lib/Passes/LLVMBuild.txt +++ llvm/trunk/lib/Passes/LLVMBuild.txt @@ -19,4 +19,4 @@ type = Library name = Passes parent = Libraries -required_libraries = Analysis Core IPA IPO InstCombine Scalar Support TransformUtils Vectorize +required_libraries = Analysis Core IPO InstCombine Scalar Support TransformUtils Vectorize Index: llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt =================================================================== --- llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt +++ llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt @@ -20,4 +20,4 @@ name = IPO parent = Transforms library_name = ipo -required_libraries = Analysis Core IPA InstCombine Scalar Support TransformUtils Vectorize +required_libraries = Analysis Core InstCombine Scalar Support TransformUtils Vectorize Index: llvm/trunk/lib/Transforms/Utils/LLVMBuild.txt =================================================================== --- llvm/trunk/lib/Transforms/Utils/LLVMBuild.txt +++ llvm/trunk/lib/Transforms/Utils/LLVMBuild.txt @@ -19,4 +19,4 @@ type = Library name = TransformUtils parent = Transforms -required_libraries = Analysis Core IPA Support +required_libraries = Analysis Core Support Index: llvm/trunk/tools/bugpoint/CMakeLists.txt =================================================================== --- llvm/trunk/tools/bugpoint/CMakeLists.txt +++ llvm/trunk/tools/bugpoint/CMakeLists.txt @@ -3,7 +3,6 @@ BitWriter CodeGen Core - IPA IPO IRReader InstCombine Index: llvm/trunk/tools/bugpoint/bugpoint.cpp =================================================================== --- llvm/trunk/tools/bugpoint/bugpoint.cpp +++ llvm/trunk/tools/bugpoint/bugpoint.cpp @@ -126,7 +126,6 @@ initializeVectorization(Registry); initializeIPO(Registry); initializeAnalysis(Registry); - initializeIPA(Registry); initializeTransformUtils(Registry); initializeInstCombine(Registry); initializeInstrumentation(Registry); Index: llvm/trunk/tools/llvm-shlib/CMakeLists.txt =================================================================== --- llvm/trunk/tools/llvm-shlib/CMakeLists.txt +++ llvm/trunk/tools/llvm-shlib/CMakeLists.txt @@ -18,7 +18,6 @@ DebugInfoDWARF DebugInfoPDB ExecutionEngine - IPA IPO IRReader InstCombine Index: llvm/trunk/tools/llvm-stress/CMakeLists.txt =================================================================== --- llvm/trunk/tools/llvm-stress/CMakeLists.txt +++ llvm/trunk/tools/llvm-stress/CMakeLists.txt @@ -1,6 +1,6 @@ set(LLVM_LINK_COMPONENTS + Analysis Core - IPA Support ) Index: llvm/trunk/tools/opt/CMakeLists.txt =================================================================== --- llvm/trunk/tools/opt/CMakeLists.txt +++ llvm/trunk/tools/opt/CMakeLists.txt @@ -4,7 +4,6 @@ BitWriter CodeGen Core - IPA IPO IRReader InstCombine Index: llvm/trunk/tools/opt/opt.cpp =================================================================== --- llvm/trunk/tools/opt/opt.cpp +++ llvm/trunk/tools/opt/opt.cpp @@ -312,7 +312,6 @@ initializeVectorization(Registry); initializeIPO(Registry); initializeAnalysis(Registry); - initializeIPA(Registry); initializeTransformUtils(Registry); initializeInstCombine(Registry); initializeInstrumentation(Registry); Index: llvm/trunk/unittests/Analysis/CMakeLists.txt =================================================================== --- llvm/trunk/unittests/Analysis/CMakeLists.txt +++ llvm/trunk/unittests/Analysis/CMakeLists.txt @@ -1,5 +1,4 @@ set(LLVM_LINK_COMPONENTS - IPA Analysis AsmParser Core Index: llvm/trunk/unittests/Analysis/Makefile =================================================================== --- llvm/trunk/unittests/Analysis/Makefile +++ llvm/trunk/unittests/Analysis/Makefile @@ -9,7 +9,7 @@ LEVEL = ../.. TESTNAME = Analysis -LINK_COMPONENTS := ipa analysis asmparser +LINK_COMPONENTS := analysis asmparser include $(LEVEL)/Makefile.config include $(LLVM_SRC_ROOT)/unittests/Makefile.unittest Index: llvm/trunk/unittests/IR/CMakeLists.txt =================================================================== --- llvm/trunk/unittests/IR/CMakeLists.txt +++ llvm/trunk/unittests/IR/CMakeLists.txt @@ -2,7 +2,6 @@ Analysis AsmParser Core - IPA Support ) Index: llvm/trunk/unittests/IR/Makefile =================================================================== --- llvm/trunk/unittests/IR/Makefile +++ llvm/trunk/unittests/IR/Makefile @@ -9,7 +9,7 @@ LEVEL = ../.. TESTNAME = IR -LINK_COMPONENTS := core ipa asmparser +LINK_COMPONENTS := core analysis asmparser include $(LEVEL)/Makefile.config include $(LLVM_SRC_ROOT)/unittests/Makefile.unittest