llvm/llvm/lib/Transforms/Instrumentation/PGOCtxProfLowering.cpp

//===- PGOCtxProfLowering.cpp - Contextual PGO Instr. Lowering ------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//

#include "llvm/Transforms/Instrumentation/PGOCtxProfLowering.h"
#include "llvm/Analysis/CtxProfAnalysis.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/IR/Analysis.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/Support/CommandLine.h"
#include <utility>

usingnamespacellvm;

#define DEBUG_TYPE …

static cl::list<std::string> ContextRoots(
    "profile-context-root", cl::Hidden,
    cl::desc(
        "A function name, assumed to be global, which will be treated as the "
        "root of an interesting graph, which will be profiled independently "
        "from other similar graphs."));

bool PGOCtxProfLoweringPass::isCtxIRPGOInstrEnabled() { … }

// the names of symbols we expect in compiler-rt. Using a namespace for
// readability.
namespace CompilerRtAPINames {
static auto StartCtx = …;
static auto ReleaseCtx = …;
static auto GetCtx = …;
static auto ExpectedCalleeTLS = …;
static auto CallsiteTLS = …;
} // namespace CompilerRtAPINames

namespace {
// The lowering logic and state.
class CtxInstrumentationLowerer final { … };

// llvm.instrprof.increment[.step] captures the total number of counters as one
// of its parameters, and llvm.instrprof.callsite captures the total number of
// callsites. Those values are the same for instances of those intrinsics in
// this function. Find the first instance of each and return them.
std::pair<uint32_t, uint32_t> getNumCountersAndCallsites(const Function &F) { … }
} // namespace

// set up tie-in with compiler-rt.
// NOTE!!!
// These have to match compiler-rt/lib/ctx_profile/CtxInstrProfiling.h
CtxInstrumentationLowerer::CtxInstrumentationLowerer(Module &M,
                                                     ModuleAnalysisManager &MAM)
    : … { … }

PreservedAnalyses PGOCtxProfLoweringPass::run(Module &M,
                                              ModuleAnalysisManager &MAM) { … }

bool CtxInstrumentationLowerer::lowerFunction(Function &F) { … }