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//===- ReplayInlineAdvisor.cpp - Replay InlineAdvisor ---------------------===//
//
// 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 implements ReplayInlineAdvisor that replays inline decisions based
// on previous inline remarks from optimization remark log. This is a best
// effort approach useful for testing compiler/source changes while holding
// inlining steady.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ReplayInlineAdvisor.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Support/LineIterator.h"
#include "llvm/Support/MemoryBuffer.h"
#include <memory>
using namespace llvm;
#define DEBUG_TYPE "replay-inline"
ReplayInlineAdvisor::ReplayInlineAdvisor(
Module &M, FunctionAnalysisManager &FAM, LLVMContext &Context,
std::unique_ptr<InlineAdvisor> OriginalAdvisor,
const ReplayInlinerSettings &ReplaySettings, bool EmitRemarks,
InlineContext IC)
: InlineAdvisor(M, FAM, IC), OriginalAdvisor(std::move(OriginalAdvisor)),
ReplaySettings(ReplaySettings), EmitRemarks(EmitRemarks) {
auto BufferOrErr = MemoryBuffer::getFileOrSTDIN(ReplaySettings.ReplayFile);
std::error_code EC = BufferOrErr.getError();
if (EC) {
Context.emitError("Could not open remarks file: " + EC.message());
return;
}
// Example for inline remarks to parse:
// main:3:1.1: '_Z3subii' inlined into 'main' at callsite sum:1 @
// main:3:1.1;
// We use the callsite string after `at callsite` to replay inlining.
line_iterator LineIt(*BufferOrErr.get(), /*SkipBlanks=*/true);
const std::string PositiveRemark = "' inlined into '";
const std::string NegativeRemark = "' will not be inlined into '";
for (; !LineIt.is_at_eof(); ++LineIt) {
StringRef Line = *LineIt;
auto Pair = Line.split(" at callsite ");
bool IsPositiveRemark = true;
if (Pair.first.contains(NegativeRemark))
IsPositiveRemark = false;
auto CalleeCaller =
Pair.first.split(IsPositiveRemark ? PositiveRemark : NegativeRemark);
StringRef Callee = CalleeCaller.first.rsplit(": '").second;
StringRef Caller = CalleeCaller.second.rsplit("'").first;
auto CallSite = Pair.second.split(";").first;
if (Callee.empty() || Caller.empty() || CallSite.empty()) {
Context.emitError("Invalid remark format: " + Line);
return;
}
std::string Combined = (Callee + CallSite).str();
InlineSitesFromRemarks[Combined] = IsPositiveRemark;
if (ReplaySettings.ReplayScope == ReplayInlinerSettings::Scope::Function)
CallersToReplay.insert(Caller);
}
HasReplayRemarks = true;
}
std::unique_ptr<InlineAdvisor>
llvm::getReplayInlineAdvisor(Module &M, FunctionAnalysisManager &FAM,
LLVMContext &Context,
std::unique_ptr<InlineAdvisor> OriginalAdvisor,
const ReplayInlinerSettings &ReplaySettings,
bool EmitRemarks, InlineContext IC) {
auto Advisor = std::make_unique<ReplayInlineAdvisor>(
M, FAM, Context, std::move(OriginalAdvisor), ReplaySettings, EmitRemarks,
IC);
if (!Advisor->areReplayRemarksLoaded())
Advisor.reset();
return Advisor;
}
std::unique_ptr<InlineAdvice> ReplayInlineAdvisor::getAdviceImpl(CallBase &CB) {
assert(HasReplayRemarks);
Function &Caller = *CB.getCaller();
auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(Caller);
// Decision not made by replay system
if (!hasInlineAdvice(*CB.getFunction())) {
// If there's a registered original advisor, return its decision
if (OriginalAdvisor)
return OriginalAdvisor->getAdvice(CB);
// If no decision is made above, return non-decision
return {};
}
std::string CallSiteLoc =
formatCallSiteLocation(CB.getDebugLoc(), ReplaySettings.ReplayFormat);
StringRef Callee = CB.getCalledFunction()->getName();
std::string Combined = (Callee + CallSiteLoc).str();
// Replay decision, if it has one
auto Iter = InlineSitesFromRemarks.find(Combined);
if (Iter != InlineSitesFromRemarks.end()) {
if (InlineSitesFromRemarks[Combined]) {
LLVM_DEBUG(dbgs() << "Replay Inliner: Inlined " << Callee << " @ "
<< CallSiteLoc << "\n");
return std::make_unique<DefaultInlineAdvice>(
this, CB, llvm::InlineCost::getAlways("previously inlined"), ORE,
EmitRemarks);
} else {
LLVM_DEBUG(dbgs() << "Replay Inliner: Not Inlined " << Callee << " @ "
<< CallSiteLoc << "\n");
// A negative inline is conveyed by "None" std::optional<InlineCost>
return std::make_unique<DefaultInlineAdvice>(this, CB, std::nullopt, ORE,
EmitRemarks);
}
}
// Fallback decisions
if (ReplaySettings.ReplayFallback ==
ReplayInlinerSettings::Fallback::AlwaysInline)
return std::make_unique<DefaultInlineAdvice>(
this, CB, llvm::InlineCost::getAlways("AlwaysInline Fallback"), ORE,
EmitRemarks);
else if (ReplaySettings.ReplayFallback ==
ReplayInlinerSettings::Fallback::NeverInline)
// A negative inline is conveyed by "None" std::optional<InlineCost>
return std::make_unique<DefaultInlineAdvice>(this, CB, std::nullopt, ORE,
EmitRemarks);
else {
assert(ReplaySettings.ReplayFallback ==
ReplayInlinerSettings::Fallback::Original);
// If there's a registered original advisor, return its decision
if (OriginalAdvisor)
return OriginalAdvisor->getAdvice(CB);
}
// If no decision is made above, return non-decision
return {};
}
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