llvm/llvm/lib/CodeGen/MIRSampleProfile.cpp

//===-------- MIRSampleProfile.cpp: MIRSampleFDO (For FSAFDO) -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file provides the implementation of the MIRSampleProfile loader, mainly
// for flow sensitive SampleFDO.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/MIRSampleProfile.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
#include "llvm/CodeGen/MachinePostDominators.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/PseudoProbe.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/VirtualFileSystem.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/SampleProfileLoaderBaseImpl.h"
#include "llvm/Transforms/Utils/SampleProfileLoaderBaseUtil.h"
#include <optional>

usingnamespacellvm;
usingnamespacesampleprof;
usingnamespacellvm::sampleprofutil;
ProfileCount;

#define DEBUG_TYPE …

static cl::opt<bool> ShowFSBranchProb(
    "show-fs-branchprob", cl::Hidden, cl::init(false),
    cl::desc("Print setting flow sensitive branch probabilities"));
static cl::opt<unsigned> FSProfileDebugProbDiffThreshold(
    "fs-profile-debug-prob-diff-threshold", cl::init(10),
    cl::desc("Only show debug message if the branch probility is greater than "
             "this value (in percentage)."));

static cl::opt<unsigned> FSProfileDebugBWThreshold(
    "fs-profile-debug-bw-threshold", cl::init(10000),
    cl::desc("Only show debug message if the source branch weight is greater "
             " than this value."));

static cl::opt<bool> ViewBFIBefore("fs-viewbfi-before", cl::Hidden,
                                   cl::init(false),
                                   cl::desc("View BFI before MIR loader"));
static cl::opt<bool> ViewBFIAfter("fs-viewbfi-after", cl::Hidden,
                                  cl::init(false),
                                  cl::desc("View BFI after MIR loader"));

namespace llvm {
extern cl::opt<bool> ImprovedFSDiscriminator;
}
char MIRProfileLoaderPass::ID = …;

INITIALIZE_PASS_BEGIN(MIRProfileLoaderPass, DEBUG_TYPE,
                      "Load MIR Sample Profile",
                      /* cfg = */ false, /* is_analysis = */ false)
INITIALIZE_PASS_DEPENDENCY(MachineBlockFrequencyInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(MachineDominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(MachinePostDominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(MachineLoopInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(MachineOptimizationRemarkEmitterPass)
INITIALIZE_PASS_END(MIRProfileLoaderPass, DEBUG_TYPE, "Load MIR Sample Profile",
                    /* cfg = */ false, /* is_analysis = */ false)

char &llvm::MIRProfileLoaderPassID = …;

FunctionPass *
llvm::createMIRProfileLoaderPass(std::string File, std::string RemappingFile,
                                 FSDiscriminatorPass P,
                                 IntrusiveRefCntPtr<vfs::FileSystem> FS) { … }

namespace llvm {

// Internal option used to control BFI display only after MBP pass.
// Defined in CodeGen/MachineBlockFrequencyInfo.cpp:
// -view-block-layout-with-bfi={none | fraction | integer | count}
extern cl::opt<GVDAGType> ViewBlockLayoutWithBFI;

// Command line option to specify the name of the function for CFG dump
// Defined in Analysis/BlockFrequencyInfo.cpp:  -view-bfi-func-name=
extern cl::opt<std::string> ViewBlockFreqFuncName;

std::optional<PseudoProbe> extractProbe(const MachineInstr &MI) { … }

namespace afdo_detail {
template <> struct IRTraits<MachineBasicBlock> { … };
} // namespace afdo_detail

class MIRProfileLoader final
    : public SampleProfileLoaderBaseImpl<MachineFunction> { … };

template <>
void SampleProfileLoaderBaseImpl<MachineFunction>::computeDominanceAndLoopInfo(
    MachineFunction &F) { … }

void MIRProfileLoader::setBranchProbs(MachineFunction &F) { … }

bool MIRProfileLoader::doInitialization(Module &M) { … }

bool MIRProfileLoader::runOnFunction(MachineFunction &MF) { … }

} // namespace llvm

MIRProfileLoaderPass::MIRProfileLoaderPass(
    std::string FileName, std::string RemappingFileName, FSDiscriminatorPass P,
    IntrusiveRefCntPtr<vfs::FileSystem> FS)
    : … { … }

bool MIRProfileLoaderPass::runOnMachineFunction(MachineFunction &MF) { … }

bool MIRProfileLoaderPass::doInitialization(Module &M) { … }

void MIRProfileLoaderPass::getAnalysisUsage(AnalysisUsage &AU) const { … }