From 45c20b474e8057b8dae813b799136ca4d36bdcb7 Mon Sep 17 00:00:00 2001 From: Kit Barton Date: Thu, 6 Aug 2015 18:02:53 +0000 Subject: [PATCH] This patch changes the interface to enable the shrink wrapping optimization. It adds a new constructor, which takes a std::function predicate function that is run at the beginning of shrink wrapping to determine whether the optimization should run on the given machine function. The std::function can be overridden by each target, allowing target-specific decisions to be made on each machine function. This is necessary for PowerPC, as the decision to run shrink wrapping is partially based on the ABI. Futhermore, this operates nicely with the GCC iFunc capability, which allows option overrides on a per-function basis. Phabricator: http://reviews.llvm.org/D11421 llvm-svn: 244235 --- llvm/include/llvm/CodeGen/Passes.h | 14 ++++++----- llvm/lib/CodeGen/Passes.cpp | 24 +++---------------- llvm/lib/CodeGen/ShrinkWrap.cpp | 48 +++++++++++++++++++++++++++++++++++++- 3 files changed, 58 insertions(+), 28 deletions(-) diff --git a/llvm/include/llvm/CodeGen/Passes.h b/llvm/include/llvm/CodeGen/Passes.h index 5d82921..8301dbe 100644 --- a/llvm/include/llvm/CodeGen/Passes.h +++ b/llvm/include/llvm/CodeGen/Passes.h @@ -120,9 +120,6 @@ protected: /// Default setting for -enable-tail-merge on this target. bool EnableTailMerge; - /// Default setting for -enable-shrink-wrap on this target. - bool EnableShrinkWrap; - public: TargetPassConfig(TargetMachine *tm, PassManagerBase &pm); // Dummy constructor. @@ -190,9 +187,6 @@ public: /// Return true if the optimized regalloc pipeline is enabled. bool getOptimizeRegAlloc() const; - /// Return true if shrink wrapping is enabled. - bool getEnableShrinkWrap() const; - /// Return true if the default global register allocator is in use and /// has not be overriden on the command line with '-regalloc=...' bool usingDefaultRegAlloc() const; @@ -361,6 +355,14 @@ protected: /// Add a pass to perform basic verification of the machine function if /// verification is enabled. void addVerifyPass(const std::string &Banner); + + /// Create an instance of ShrinkWrap using the runShrinkWrap predicate + /// function. + FunctionPass *createShrinkWrapPass(); + + /// Predicate function passed to a ShrinkWrap object to determine if shrink + /// wrapping should be run on a MachineFunction. + virtual bool runShrinkWrap(const MachineFunction &Fn) const; }; } // namespace llvm diff --git a/llvm/lib/CodeGen/Passes.cpp b/llvm/lib/CodeGen/Passes.cpp index 5b6e6f0..f36e513 100644 --- a/llvm/lib/CodeGen/Passes.cpp +++ b/llvm/lib/CodeGen/Passes.cpp @@ -53,9 +53,6 @@ static cl::opt DisableMachineLICM("disable-machine-licm", cl::Hidden, cl::desc("Disable Machine LICM")); static cl::opt DisableMachineCSE("disable-machine-cse", cl::Hidden, cl::desc("Disable Machine Common Subexpression Elimination")); -static cl::opt - EnableShrinkWrapOpt("enable-shrink-wrap", cl::Hidden, - cl::desc("enable the shrink-wrapping pass")); static cl::opt OptimizeRegAlloc( "optimize-regalloc", cl::Hidden, cl::desc("Enable optimized register allocation compilation path.")); @@ -218,7 +215,7 @@ TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm) : ImmutablePass(ID), PM(&pm), StartBefore(nullptr), StartAfter(nullptr), StopAfter(nullptr), Started(true), Stopped(false), AddingMachinePasses(false), TM(tm), Impl(nullptr), Initialized(false), - DisableVerify(false), EnableTailMerge(true), EnableShrinkWrap(false) { + DisableVerify(false), EnableTailMerge(true) { Impl = new PassConfigImpl(); @@ -540,8 +537,8 @@ void TargetPassConfig::addMachinePasses() { addPostRegAlloc(); // Insert prolog/epilog code. Eliminate abstract frame index references... - if (getEnableShrinkWrap()) - addPass(&ShrinkWrapID); + if (getOptLevel() != CodeGenOpt::None) + addPass(createShrinkWrapPass()); addPass(&PrologEpilogCodeInserterID); /// Add passes that optimize machine instructions after register allocation. @@ -620,21 +617,6 @@ void TargetPassConfig::addMachineSSAOptimization() { addPass(&DeadMachineInstructionElimID); } -bool TargetPassConfig::getEnableShrinkWrap() const { - switch (EnableShrinkWrapOpt) { - case cl::BOU_UNSET: - return EnableShrinkWrap && getOptLevel() != CodeGenOpt::None; - // If EnableShrinkWrap is set, it takes precedence on whatever the - // target sets. The rational is that we assume we want to test - // something related to shrink-wrapping. - case cl::BOU_TRUE: - return true; - case cl::BOU_FALSE: - return false; - } - llvm_unreachable("Invalid shrink-wrapping state"); -} - //===---------------------------------------------------------------------===// /// Register Allocation Pass Configuration //===---------------------------------------------------------------------===// diff --git a/llvm/lib/CodeGen/ShrinkWrap.cpp b/llvm/lib/CodeGen/ShrinkWrap.cpp index 4463cc7..f8ec1f3 100644 --- a/llvm/lib/CodeGen/ShrinkWrap.cpp +++ b/llvm/lib/CodeGen/ShrinkWrap.cpp @@ -68,11 +68,16 @@ #include "llvm/Target/TargetInstrInfo.h" // To access TargetInstrInfo. #include "llvm/Target/TargetSubtargetInfo.h" +#include "llvm/Support/CommandLine.h" #define DEBUG_TYPE "shrink-wrap" using namespace llvm; +static cl::opt + EnableShrinkWrapOpt("enable-shrink-wrap", cl::Hidden, + cl::desc("enable the shrink-wrapping pass")); + STATISTIC(NumFunc, "Number of functions"); STATISTIC(NumCandidates, "Number of shrink-wrapping candidates"); STATISTIC(NumCandidatesDropped, @@ -154,6 +159,11 @@ public: ShrinkWrap() : MachineFunctionPass(ID) { initializeShrinkWrapPass(*PassRegistry::getPassRegistry()); } + + ShrinkWrap(std::function Ftor) : + MachineFunctionPass(ID), PredicateFtor(Ftor) { + initializeShrinkWrapPass(*PassRegistry::getPassRegistry()); + } void getAnalysisUsage(AnalysisUsage &AU) const override { AU.setPreservesAll(); @@ -171,6 +181,15 @@ public: /// \brief Perform the shrink-wrapping analysis and update /// the MachineFrameInfo attached to \p MF with the results. bool runOnMachineFunction(MachineFunction &MF) override; + +private: + /// \brief Predicate function to determine if shrink wrapping should run. + /// + /// This function will be run at the beginning of shrink wrapping and + /// determine whether shrink wrapping should run on the given MachineFunction. + /// \param[in] MF The MachineFunction to run shrink wrapping on. + /// \return true if shrink wrapping should be run, false otherwise. + std::function PredicateFtor; }; } // End anonymous namespace. @@ -301,8 +320,12 @@ void ShrinkWrap::updateSaveRestorePoints(MachineBasicBlock &MBB) { } bool ShrinkWrap::runOnMachineFunction(MachineFunction &MF) { - if (MF.empty()) + if (PredicateFtor && !PredicateFtor(MF)) return false; + + if (MF.empty() || skipOptnoneFunction(*MF.getFunction())) + return false; + DEBUG(dbgs() << "**** Analysing " << MF.getName() << '\n'); init(MF); @@ -386,3 +409,26 @@ bool ShrinkWrap::runOnMachineFunction(MachineFunction &MF) { ++NumCandidates; return false; } + +/// If EnableShrinkWrap is set run shrink wrapping on the given Machine +/// Function. Otherwise, shrink wrapping is disabled. +/// This function can be overridden in each target-specific TargetPassConfig +/// class to allow different predicate logic for each target. +bool TargetPassConfig::runShrinkWrap(const MachineFunction &Fn) const { + switch (EnableShrinkWrapOpt) { + case cl::BOU_TRUE: + return true; + case cl::BOU_UNSET: + case cl::BOU_FALSE: + return false; + } + llvm_unreachable("Invalid shrink-wrapping state"); +} + +/// Create a ShrinkWrap FunctionPass using the runShrinkWrap predicate +/// function. +FunctionPass *TargetPassConfig::createShrinkWrapPass() { + std::function Ftor = + std::bind(&TargetPassConfig::runShrinkWrap, this, std::placeholders::_1); + return new ShrinkWrap(Ftor); +} -- 2.7.4