313c657fce
The goal is to allow grafting an inline tree from Clang or GCC into a new compilation without affecting other functions. For GCC, we're doing this by extracting the inline tree from dwarf information and generating the equivalent remarks. This allows easier side-by-side asm analysis and a trial way to see if a particular inlining setup provides benefits by itself. Testing: ninja check-all Reviewed By: wenlei, mtrofin Differential Revision: https://reviews.llvm.org/D110658
110 lines
4.0 KiB
C++
110 lines
4.0 KiB
C++
//===- ReplayInlineAdvisor.cpp - Replay InlineAdvisor ---------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements ReplayInlineAdvisor that replays inline decisions based
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// on previous inline remarks from optimization remark log. This is a best
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// effort approach useful for testing compiler/source changes while holding
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// inlining steady.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/ReplayInlineAdvisor.h"
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#include "llvm/IR/DebugInfoMetadata.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/Support/LineIterator.h"
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#include <memory>
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using namespace llvm;
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#define DEBUG_TYPE "replay-inline"
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ReplayInlineAdvisor::ReplayInlineAdvisor(
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Module &M, FunctionAnalysisManager &FAM, LLVMContext &Context,
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std::unique_ptr<InlineAdvisor> OriginalAdvisor, StringRef RemarksFile,
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ReplayInlineScope Scope, bool EmitRemarks)
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: InlineAdvisor(M, FAM), OriginalAdvisor(std::move(OriginalAdvisor)),
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HasReplayRemarks(false), Scope(Scope), EmitRemarks(EmitRemarks) {
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auto BufferOrErr = MemoryBuffer::getFileOrSTDIN(RemarksFile);
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std::error_code EC = BufferOrErr.getError();
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if (EC) {
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Context.emitError("Could not open remarks file: " + EC.message());
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return;
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}
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// Example for inline remarks to parse:
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// main:3:1.1: '_Z3subii' inlined into 'main' at callsite sum:1 @
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// main:3:1.1;
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// We use the callsite string after `at callsite` to replay inlining.
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line_iterator LineIt(*BufferOrErr.get(), /*SkipBlanks=*/true);
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for (; !LineIt.is_at_eof(); ++LineIt) {
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StringRef Line = *LineIt;
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auto Pair = Line.split(" at callsite ");
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auto CalleeCaller = Pair.first.split("' inlined into '");
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StringRef Callee = CalleeCaller.first.rsplit(": '").second;
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StringRef Caller = CalleeCaller.second.rsplit("'").first;
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auto CallSite = Pair.second.split(";").first;
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if (Callee.empty() || Caller.empty() || CallSite.empty()) {
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Context.emitError("Invalid remark format: " + Line);
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return;
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}
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std::string Combined = (Callee + CallSite).str();
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InlineSitesFromRemarks[Combined] = false;
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if (Scope == ReplayInlineScope::Function)
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CallersToReplay.insert(Caller);
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}
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HasReplayRemarks = true;
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}
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std::unique_ptr<InlineAdvisor> llvm::getReplayInlineAdvisor(
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Module &M, FunctionAnalysisManager &FAM, LLVMContext &Context,
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std::unique_ptr<InlineAdvisor> OriginalAdvisor, StringRef RemarksFile,
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ReplayInlineScope Scope, bool EmitRemarks) {
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auto Advisor = std::make_unique<ReplayInlineAdvisor>(
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M, FAM, Context, std::move(OriginalAdvisor), RemarksFile, Scope,
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EmitRemarks);
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if (!Advisor->areReplayRemarksLoaded())
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Advisor.reset();
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return Advisor;
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}
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std::unique_ptr<InlineAdvice> ReplayInlineAdvisor::getAdviceImpl(CallBase &CB) {
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assert(HasReplayRemarks);
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Function &Caller = *CB.getCaller();
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auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(Caller);
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Optional<InlineCost> InlineRecommended;
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if (Scope == ReplayInlineScope::Module ||
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CallersToReplay.count(CB.getFunction()->getName())) {
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std::string CallSiteLoc = getCallSiteLocation(CB.getDebugLoc());
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StringRef Callee = CB.getCalledFunction()->getName();
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std::string Combined = (Callee + CallSiteLoc).str();
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auto Iter = InlineSitesFromRemarks.find(Combined);
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if (Iter != InlineSitesFromRemarks.end()) {
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InlineSitesFromRemarks[Combined] = true;
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InlineRecommended = llvm::InlineCost::getAlways("previously inlined");
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}
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} else if (Scope == ReplayInlineScope::Function) {
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if (OriginalAdvisor)
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return OriginalAdvisor->getAdvice(CB);
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return {};
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}
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return std::make_unique<DefaultInlineAdvice>(this, CB, InlineRecommended, ORE,
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EmitRemarks);
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}
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