Index: include/llvm/CodeGen/Passes.h =================================================================== --- include/llvm/CodeGen/Passes.h +++ include/llvm/CodeGen/Passes.h @@ -582,6 +582,9 @@ /// StackSlotColoring - This pass performs stack slot coloring. extern char &StackSlotColoringID; + /// \brief This pass lays out funclets contiguously. + extern char &FuncletLayoutID; + /// createStackProtectorPass - This pass adds stack protectors to functions. /// FunctionPass *createStackProtectorPass(const TargetMachine *TM); Index: include/llvm/InitializePasses.h =================================================================== --- include/llvm/InitializePasses.h +++ include/llvm/InitializePasses.h @@ -299,6 +299,7 @@ void initializeLoopDistributePass(PassRegistry&); void initializeSjLjEHPreparePass(PassRegistry&); void initializeDemandedBitsPass(PassRegistry&); +void initializeFuncletLayoutPass(PassRegistry &); } #endif Index: lib/CodeGen/CMakeLists.txt =================================================================== --- lib/CodeGen/CMakeLists.txt +++ lib/CodeGen/CMakeLists.txt @@ -26,6 +26,7 @@ ExpandISelPseudos.cpp ExpandPostRAPseudos.cpp FaultMaps.cpp + FuncletLayout.cpp GCMetadata.cpp GCMetadataPrinter.cpp GCRootLowering.cpp Index: lib/CodeGen/CodeGen.cpp =================================================================== --- lib/CodeGen/CodeGen.cpp +++ lib/CodeGen/CodeGen.cpp @@ -29,6 +29,7 @@ initializeExpandISelPseudosPass(Registry); initializeExpandPostRAPass(Registry); initializeFinalizeMachineBundlesPass(Registry); + initializeFuncletLayoutPass(Registry); initializeGCMachineCodeAnalysisPass(Registry); initializeGCModuleInfoPass(Registry); initializeIfConverterPass(Registry); Index: lib/CodeGen/FuncletLayout.cpp =================================================================== --- /dev/null +++ lib/CodeGen/FuncletLayout.cpp @@ -0,0 +1,91 @@ +//===-- FuncletLayout.cpp - Contiguously lay out funclets -----------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements basic block placement transformations which result in +// funclets being contiguous. +// +//===----------------------------------------------------------------------===// +#include "llvm/CodeGen/Passes.h" +#include "llvm/ADT/MapVector.h" +#include "llvm/CodeGen/MachineBasicBlock.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineFunctionPass.h" +using namespace llvm; + +#define DEBUG_TYPE "funclet-layout" + +namespace { +class FuncletLayout : public MachineFunctionPass { +public: + static char ID; // Pass identification, replacement for typeid + FuncletLayout() : MachineFunctionPass(ID) { + initializeFuncletLayoutPass(*PassRegistry::getPassRegistry()); + } + + bool runOnMachineFunction(MachineFunction &F) override; +}; +} + +static void +collectFuncletMembers(MapVector &FuncletMembership, + int Funclet, MachineBasicBlock *MBB) { + // Don't revisit blocks. + if (FuncletMembership.count(MBB) > 0) + return; + + // Add this MBB to our funclet. + FuncletMembership[MBB] = Funclet; + + bool IsReturn = false; + int NumTerminators = 0; + for (MachineInstr &MI : MBB->terminators()) { + IsReturn |= MI.isReturn(); + ++NumTerminators; + } + assert((!IsReturn || NumTerminators == 1) && + "Expected only one terminator when a return is present!"); + + // Returns are boundaries where funclet transfer can occur, don't follow + // successors. + if (IsReturn) + return; + + for (MachineBasicBlock *SMBB : MBB->successors()) + if (!SMBB->isEHPad()) + collectFuncletMembers(FuncletMembership, Funclet, SMBB); +} + +char FuncletLayout::ID = 0; +char &llvm::FuncletLayoutID = FuncletLayout::ID; +INITIALIZE_PASS(FuncletLayout, "funclet-layout", + "Contiguously Lay Out Funclets", false, false) + +bool FuncletLayout::runOnMachineFunction(MachineFunction &F) { + SmallVector FuncletBlocks; + for (MachineBasicBlock &MBB : F) + if (MBB.isEHPad()) + FuncletBlocks.push_back(&MBB); + + // We don't have anything to do if there aren't any EH pads. + if (FuncletBlocks.empty()) + return false; + + MapVector FuncletMembership; + for (MachineBasicBlock *MBB : FuncletBlocks) + collectFuncletMembers(FuncletMembership, MBB->getNumber(), MBB); + + for (std::pair &FuncletMember : + FuncletMembership) { + // Move this block to the end of the function. + MachineBasicBlock *MBB = FuncletMember.first; + MBB->moveAfter(--F.end()); + } + + return true; +} Index: lib/CodeGen/Passes.cpp =================================================================== --- lib/CodeGen/Passes.cpp +++ lib/CodeGen/Passes.cpp @@ -582,6 +582,8 @@ addPreEmitPass(); + addPass(&FuncletLayoutID, false); + addPass(&StackMapLivenessID, false); AddingMachinePasses = false; Index: test/CodeGen/X86/funclet-layout.ll =================================================================== --- /dev/null +++ test/CodeGen/X86/funclet-layout.ll @@ -0,0 +1,41 @@ +; RUN: llc -mtriple=x86_64-windows-msvc < %s | FileCheck %s + +target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-pc-windows-msvc" + +define void @f(i1 %B) personality i32 (...)* @__CxxFrameHandler3 { +entry: + invoke void @g() + to label %unreachable unwind label %catch.dispatch + +catch.dispatch: + %cp = catchpad [i8* null, i32 64, i8* null] + to label %catch unwind label %catchendblock + +catch: + br i1 %B, label %catchret, label %catch + +catchret: + catchret %cp to label %try.cont + +try.cont: + ret void + +catchendblock: + catchendpad unwind to caller + +unreachable: + unreachable +} + +; The entry funclet is contains %entry and %try.cont +; CHECK: # %entry +; CHECK: # %try.cont + +; The catch funclet is contains %catch and %catchret +; CHECK: # %catch +; CHECK: # %catchret + +declare void @g() + +declare i32 @__CxxFrameHandler3(...)