Add opt-bisect support for region passes

[efriedma]

Summary

This is necessary to get opt-bisect working with polly.

[MatzeB]

This looks straightforward. LGTM.

lib/Analysis/RegionPass.cpp

286 ↗

(On Diff #100956)

I'd use a reference as it cannot be nullptr.

lib/IR/OptBisect.cpp

64–65 ↗

(On Diff #100956)

Printing the names of the entry and exit blocks of a region?

[andrew.w.kaylor]

Thanks for doing this!

llvm/trunk/include/llvm/Analysis/RegionPass.h

public:
 
   void assignPassManager(PMStack &PMS,
                          PassManagerType PMT = PMT_RegionPassManager) override;
 
   PassManagerType getPotentialPassManagerType() const override {
     return PMT_RegionPassManager;
   }
   //@}
+
+protected:
+  /// Optional passes call this function to check whether the pass should be
+  /// skipped. This is the case when optimization bisect is over the limit.
+  bool skipRegion(Region &R) const;
 };
 
 /// @brief The pass manager to schedule RegionPasses.
 class RGPassManager : public FunctionPass, public PMDataManager {
   std::deque<Region*> RQ;
   bool skipThisRegion;
   bool redoThisRegion;
   RegionInfo *RI;

llvm/trunk/lib/Analysis/RegionPass.cpp

 // This file implements RegionPass and RGPassManager. All region optimization
 // and transformation passes are derived from RegionPass. RGPassManager is
 // responsible for managing RegionPasses.
 // Most of this code has been COPIED from LoopPass.cpp
 //
 //===----------------------------------------------------------------------===//
 #include "llvm/Analysis/RegionPass.h"
 #include "llvm/Analysis/RegionIterator.h"
+#include "llvm/IR/OptBisect.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "regionpassmgr"
 
 //===----------------------------------------------------------------------===//
void RegionPass::assignPassManager(PMStack &PMS,
   RGPM->add(this);
 }
 
 /// Get the printer pass
 Pass *RegionPass::createPrinterPass(raw_ostream &O,
                                   const std::string &Banner) const {
   return new PrintRegionPass(Banner, O);
 }
+
+bool RegionPass::skipRegion(Region &R) const {
+  Function &F = *R.getEntry()->getParent();
+  if (!F.getContext().getOptBisect().shouldRunPass(this, R))
+    return true;
+
+  if (F.hasFnAttribute(Attribute::OptimizeNone)) {
+    // Report this only once per function.
+    if (R.getEntry() == &F.getEntryBlock())
+      DEBUG(dbgs() << "Skipping pass '" << getPassName()
+            << "' on function " << F.getName() << "\n");
+    return true;
+  }
+  return false;
+}

llvm/trunk/lib/IR/OptBisect.cpp

 /// This file implements support for a bisecting optimizations based on a
 /// command line option.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/CallGraphSCCPass.h"
 #include "llvm/Analysis/LazyCallGraph.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/RegionInfo.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/OptBisect.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 

 }
 
 static std::string getDescription(const BasicBlock &BB) {
   return "basic block (" + BB.getName().str() + ") in function (" +
          BB.getParent()->getName().str() + ")";
 }
 
 static std::string getDescription(const Loop &L) {
-  // FIXME: I'd like to be able to provide a better description here, but
-  //        calling L->getHeader() would introduce a new dependency on the
-  //        LLVMCore library.
+  // FIXME: Move into LoopInfo so we can get a better description
+  // (and avoid a circular dependency between IR and Analysis).
   return "loop";
 }
 
+static std::string getDescription(const Region &R) {
+  // FIXME: Move into RegionInfo so we can get a better description
+  // (and avoid a circular dependency between IR and Analysis).
+  return "region";
+}
+
 static std::string getDescription(const CallGraphSCC &SCC) {
+  // FIXME: Move into CallGraphSCCPass to avoid circular dependency between
+  // IR and Analysis.
   std::string Desc = "SCC (";
   bool First = true;
   for (CallGraphNode *CGN : SCC) {
     if (First)
       First = false;
     else
       Desc += ", ";
     Function *F = CGN->getFunction();
     if (F)
       Desc += F->getName();
     else
       Desc += "<<null function>>";
   }
   Desc += ")";
   return Desc;
 }
 
 // Force instantiations.
 template bool OptBisect::shouldRunPass(const Pass *, const Module &);
 template bool OptBisect::shouldRunPass(const Pass *, const Function &);
 template bool OptBisect::shouldRunPass(const Pass *, const BasicBlock &);
 template bool OptBisect::shouldRunPass(const Pass *, const Loop &);
 template bool OptBisect::shouldRunPass(const Pass *, const CallGraphSCC &);
+template bool OptBisect::shouldRunPass(const Pass *, const Region &);
 
 template <class UnitT>
 bool OptBisect::shouldRunPass(const Pass *P, const UnitT &U) {
   if (!BisectEnabled)
     return true;
   return checkPass(P->getPassName(), getDescription(U));
 }