From 048d7e541d4bb2418f927d03dc2b6a683e27e985 Mon Sep 17 00:00:00 2001 From: David Majnemer Date: Thu, 17 Sep 2015 20:45:18 +0000 Subject: [PATCH] [WinEH] Add a funclet layout pass Windows EH funclets need to be contiguous. The FuncletLayout pass will ensure that the funclets are together and begin with a funclet entry MBB. Differential Revision: http://reviews.llvm.org/D12943 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247937 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/Passes.h | 3 + include/llvm/InitializePasses.h | 1 + lib/CodeGen/CMakeLists.txt | 1 + lib/CodeGen/CodeGen.cpp | 1 + lib/CodeGen/FuncletLayout.cpp | 97 ++++++++++++++++++++++++++++++ lib/CodeGen/Passes.cpp | 2 + test/CodeGen/X86/funclet-layout.ll | 45 ++++++++++++++ 7 files changed, 150 insertions(+) create mode 100644 lib/CodeGen/FuncletLayout.cpp create mode 100644 test/CodeGen/X86/funclet-layout.ll diff --git a/include/llvm/CodeGen/Passes.h b/include/llvm/CodeGen/Passes.h index 13108d9d857..b06c576cd45 100644 --- a/include/llvm/CodeGen/Passes.h +++ b/include/llvm/CodeGen/Passes.h @@ -582,6 +582,9 @@ namespace llvm { /// 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); diff --git a/include/llvm/InitializePasses.h b/include/llvm/InitializePasses.h index dc5c25cf15d..2b03759605f 100644 --- a/include/llvm/InitializePasses.h +++ b/include/llvm/InitializePasses.h @@ -299,6 +299,7 @@ void initializeFloat2IntPass(PassRegistry&); void initializeLoopDistributePass(PassRegistry&); void initializeSjLjEHPreparePass(PassRegistry&); void initializeDemandedBitsPass(PassRegistry&); +void initializeFuncletLayoutPass(PassRegistry &); } #endif diff --git a/lib/CodeGen/CMakeLists.txt b/lib/CodeGen/CMakeLists.txt index b2a1efc9c25..9c63dc7a0fd 100644 --- a/lib/CodeGen/CMakeLists.txt +++ b/lib/CodeGen/CMakeLists.txt @@ -26,6 +26,7 @@ add_llvm_library(LLVMCodeGen ExpandISelPseudos.cpp ExpandPostRAPseudos.cpp FaultMaps.cpp + FuncletLayout.cpp GCMetadata.cpp GCMetadataPrinter.cpp GCRootLowering.cpp diff --git a/lib/CodeGen/CodeGen.cpp b/lib/CodeGen/CodeGen.cpp index 155c5ecec77..7d18058db50 100644 --- a/lib/CodeGen/CodeGen.cpp +++ b/lib/CodeGen/CodeGen.cpp @@ -29,6 +29,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) { initializeExpandISelPseudosPass(Registry); initializeExpandPostRAPass(Registry); initializeFinalizeMachineBundlesPass(Registry); + initializeFuncletLayoutPass(Registry); initializeGCMachineCodeAnalysisPass(Registry); initializeGCModuleInfoPass(Registry); initializeIfConverterPass(Registry); diff --git a/lib/CodeGen/FuncletLayout.cpp b/lib/CodeGen/FuncletLayout.cpp new file mode 100644 index 00000000000..9b40a1a7558 --- /dev/null +++ b/lib/CodeGen/FuncletLayout.cpp @@ -0,0 +1,97 @@ +//===-- 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" +#include "llvm/CodeGen/MachineModuleInfo.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) { + // We don't have anything to do if there aren't any EH pads. + if (!F.getMMI().hasEHFunclets()) + return false; + + SmallVector FuncletBlocks; + for (MachineBasicBlock &MBB : F) + if (MBB.isEHFuncletEntry()) + 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()); + } + + // Conservatively assume we changed something. + return true; +} diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp index ee559e62245..7ea7b6e45ce 100644 --- a/lib/CodeGen/Passes.cpp +++ b/lib/CodeGen/Passes.cpp @@ -582,6 +582,8 @@ void TargetPassConfig::addMachinePasses() { addPreEmitPass(); + addPass(&FuncletLayoutID, false); + addPass(&StackMapLivenessID, false); AddingMachinePasses = false; diff --git a/test/CodeGen/X86/funclet-layout.ll b/test/CodeGen/X86/funclet-layout.ll new file mode 100644 index 00000000000..9e6fbb6fbb5 --- /dev/null +++ b/test/CodeGen/X86/funclet-layout.ll @@ -0,0 +1,45 @@ +; 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 +} + +; CHECK-LABEL: f: + +; The entry funclet contains %entry and %try.cont +; CHECK: # %entry +; CHECK: # %try.cont +; CHECK: retq + +; The catch funclet contains %catch and %catchret +; CHECK: # %catch +; CHECK: # %catchret +; CHECK: retq + +declare void @g() + +declare i32 @__CxxFrameHandler3(...) -- 2.34.1