302 lines
11 KiB
C++
302 lines
11 KiB
C++
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//===- CFGPrinter.cpp - DOT printer for the control flow graph ------------===//
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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 defines a `-dot-cfg` analysis pass, which emits the
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// `<prefix>.<fnname>.dot` file for each function in the program, with a graph
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// of the CFG for that function. The default value for `<prefix>` is `cfg` but
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// can be customized as needed.
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//
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// The other main feature of this file is that it implements the
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// Function::viewCFG method, which is useful for debugging passes which operate
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// on the CFG.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/CFGPrinter.h"
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/FileSystem.h"
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#include <algorithm>
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using namespace llvm;
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static cl::opt<std::string>
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CFGFuncName("cfg-func-name", cl::Hidden,
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cl::desc("The name of a function (or its substring)"
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" whose CFG is viewed/printed."));
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static cl::opt<std::string> CFGDotFilenamePrefix(
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"cfg-dot-filename-prefix", cl::Hidden,
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cl::desc("The prefix used for the CFG dot file names."));
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static cl::opt<bool> HideUnreachablePaths("cfg-hide-unreachable-paths",
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cl::init(false));
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static cl::opt<bool> HideDeoptimizePaths("cfg-hide-deoptimize-paths",
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cl::init(false));
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static cl::opt<bool> ShowHeatColors("cfg-heat-colors", cl::init(true),
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cl::Hidden,
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cl::desc("Show heat colors in CFG"));
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static cl::opt<bool> UseRawEdgeWeight("cfg-raw-weights", cl::init(false),
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cl::Hidden,
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cl::desc("Use raw weights for labels. "
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"Use percentages as default."));
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static cl::opt<bool>
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ShowEdgeWeight("cfg-weights", cl::init(false), cl::Hidden,
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cl::desc("Show edges labeled with weights"));
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static void writeCFGToDotFile(Function &F, BlockFrequencyInfo *BFI,
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BranchProbabilityInfo *BPI, uint64_t MaxFreq,
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bool CFGOnly = false) {
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std::string Filename =
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(CFGDotFilenamePrefix + "." + F.getName() + ".dot").str();
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errs() << "Writing '" << Filename << "'...";
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std::error_code EC;
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raw_fd_ostream File(Filename, EC, sys::fs::F_Text);
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DOTFuncInfo CFGInfo(&F, BFI, BPI, MaxFreq);
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CFGInfo.setHeatColors(ShowHeatColors);
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CFGInfo.setEdgeWeights(ShowEdgeWeight);
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CFGInfo.setRawEdgeWeights(UseRawEdgeWeight);
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if (!EC)
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WriteGraph(File, &CFGInfo, CFGOnly);
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else
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errs() << " error opening file for writing!";
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errs() << "\n";
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}
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static void viewCFG(Function &F, const BlockFrequencyInfo *BFI,
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const BranchProbabilityInfo *BPI, uint64_t MaxFreq,
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bool CFGOnly = false) {
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DOTFuncInfo CFGInfo(&F, BFI, BPI, MaxFreq);
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CFGInfo.setHeatColors(ShowHeatColors);
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CFGInfo.setEdgeWeights(ShowEdgeWeight);
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CFGInfo.setRawEdgeWeights(UseRawEdgeWeight);
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ViewGraph(&CFGInfo, "cfg." + F.getName(), CFGOnly);
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}
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namespace {
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struct CFGViewerLegacyPass : public FunctionPass {
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static char ID; // Pass identifcation, replacement for typeid
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CFGViewerLegacyPass() : FunctionPass(ID) {
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initializeCFGViewerLegacyPassPass(*PassRegistry::getPassRegistry());
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}
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bool runOnFunction(Function &F) override {
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auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
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auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI();
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viewCFG(F, BFI, BPI, getMaxFreq(F, BFI));
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return false;
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}
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void print(raw_ostream &OS, const Module * = nullptr) const override {}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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FunctionPass::getAnalysisUsage(AU);
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AU.addRequired<BlockFrequencyInfoWrapperPass>();
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AU.addRequired<BranchProbabilityInfoWrapperPass>();
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AU.setPreservesAll();
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}
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};
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}
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char CFGViewerLegacyPass::ID = 0;
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INITIALIZE_PASS(CFGViewerLegacyPass, "view-cfg", "View CFG of function", false,
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true)
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PreservedAnalyses CFGViewerPass::run(Function &F, FunctionAnalysisManager &AM) {
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auto *BFI = &AM.getResult<BlockFrequencyAnalysis>(F);
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auto *BPI = &AM.getResult<BranchProbabilityAnalysis>(F);
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viewCFG(F, BFI, BPI, getMaxFreq(F, BFI));
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return PreservedAnalyses::all();
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}
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namespace {
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struct CFGOnlyViewerLegacyPass : public FunctionPass {
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static char ID; // Pass identifcation, replacement for typeid
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CFGOnlyViewerLegacyPass() : FunctionPass(ID) {
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initializeCFGOnlyViewerLegacyPassPass(*PassRegistry::getPassRegistry());
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}
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bool runOnFunction(Function &F) override {
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auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
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auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI();
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viewCFG(F, BFI, BPI, getMaxFreq(F, BFI), /*CFGOnly=*/true);
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return false;
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}
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void print(raw_ostream &OS, const Module * = nullptr) const override {}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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FunctionPass::getAnalysisUsage(AU);
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AU.addRequired<BlockFrequencyInfoWrapperPass>();
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AU.addRequired<BranchProbabilityInfoWrapperPass>();
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AU.setPreservesAll();
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}
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};
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}
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char CFGOnlyViewerLegacyPass::ID = 0;
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INITIALIZE_PASS(CFGOnlyViewerLegacyPass, "view-cfg-only",
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"View CFG of function (with no function bodies)", false, true)
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PreservedAnalyses CFGOnlyViewerPass::run(Function &F,
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FunctionAnalysisManager &AM) {
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auto *BFI = &AM.getResult<BlockFrequencyAnalysis>(F);
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auto *BPI = &AM.getResult<BranchProbabilityAnalysis>(F);
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viewCFG(F, BFI, BPI, getMaxFreq(F, BFI), /*CFGOnly=*/true);
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return PreservedAnalyses::all();
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}
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namespace {
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struct CFGPrinterLegacyPass : public FunctionPass {
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static char ID; // Pass identification, replacement for typeid
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CFGPrinterLegacyPass() : FunctionPass(ID) {
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initializeCFGPrinterLegacyPassPass(*PassRegistry::getPassRegistry());
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}
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bool runOnFunction(Function &F) override {
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auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
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auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI();
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writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI));
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return false;
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}
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void print(raw_ostream &OS, const Module * = nullptr) const override {}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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FunctionPass::getAnalysisUsage(AU);
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AU.addRequired<BlockFrequencyInfoWrapperPass>();
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AU.addRequired<BranchProbabilityInfoWrapperPass>();
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AU.setPreservesAll();
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}
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};
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}
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char CFGPrinterLegacyPass::ID = 0;
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INITIALIZE_PASS(CFGPrinterLegacyPass, "dot-cfg",
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"Print CFG of function to 'dot' file", false, true)
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PreservedAnalyses CFGPrinterPass::run(Function &F,
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FunctionAnalysisManager &AM) {
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auto *BFI = &AM.getResult<BlockFrequencyAnalysis>(F);
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auto *BPI = &AM.getResult<BranchProbabilityAnalysis>(F);
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writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI));
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return PreservedAnalyses::all();
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}
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namespace {
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struct CFGOnlyPrinterLegacyPass : public FunctionPass {
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static char ID; // Pass identification, replacement for typeid
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CFGOnlyPrinterLegacyPass() : FunctionPass(ID) {
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initializeCFGOnlyPrinterLegacyPassPass(*PassRegistry::getPassRegistry());
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}
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bool runOnFunction(Function &F) override {
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auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
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auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI();
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writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI), /*CFGOnly=*/true);
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return false;
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}
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void print(raw_ostream &OS, const Module * = nullptr) const override {}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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FunctionPass::getAnalysisUsage(AU);
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AU.addRequired<BlockFrequencyInfoWrapperPass>();
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AU.addRequired<BranchProbabilityInfoWrapperPass>();
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AU.setPreservesAll();
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}
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};
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}
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char CFGOnlyPrinterLegacyPass::ID = 0;
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INITIALIZE_PASS(CFGOnlyPrinterLegacyPass, "dot-cfg-only",
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"Print CFG of function to 'dot' file (with no function bodies)",
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false, true)
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PreservedAnalyses CFGOnlyPrinterPass::run(Function &F,
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FunctionAnalysisManager &AM) {
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auto *BFI = &AM.getResult<BlockFrequencyAnalysis>(F);
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auto *BPI = &AM.getResult<BranchProbabilityAnalysis>(F);
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writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI), /*CFGOnly=*/true);
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return PreservedAnalyses::all();
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}
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/// viewCFG - This function is meant for use from the debugger. You can just
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/// say 'call F->viewCFG()' and a ghostview window should pop up from the
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/// program, displaying the CFG of the current function. This depends on there
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/// being a 'dot' and 'gv' program in your path.
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///
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void Function::viewCFG() const { viewCFG(false, nullptr, nullptr); }
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void Function::viewCFG(bool ViewCFGOnly, const BlockFrequencyInfo *BFI,
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const BranchProbabilityInfo *BPI) const {
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if (!CFGFuncName.empty() && !getName().contains(CFGFuncName))
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return;
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DOTFuncInfo CFGInfo(this, BFI, BPI, BFI ? getMaxFreq(*this, BFI) : 0);
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ViewGraph(&CFGInfo, "cfg" + getName(), ViewCFGOnly);
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}
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/// viewCFGOnly - This function is meant for use from the debugger. It works
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/// just like viewCFG, but it does not include the contents of basic blocks
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/// into the nodes, just the label. If you are only interested in the CFG
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/// this can make the graph smaller.
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///
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void Function::viewCFGOnly() const { viewCFGOnly(nullptr, nullptr); }
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void Function::viewCFGOnly(const BlockFrequencyInfo *BFI,
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const BranchProbabilityInfo *BPI) const {
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viewCFG(true, BFI, BPI);
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}
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FunctionPass *llvm::createCFGPrinterLegacyPassPass() {
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return new CFGPrinterLegacyPass();
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}
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FunctionPass *llvm::createCFGOnlyPrinterLegacyPassPass() {
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return new CFGOnlyPrinterLegacyPass();
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}
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void DOTGraphTraits<DOTFuncInfo *>::computeHiddenNodes(const Function *F) {
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auto evaluateBB = [&](const BasicBlock *Node) {
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if (succ_empty(Node)) {
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const Instruction *TI = Node->getTerminator();
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isHiddenBasicBlock[Node] =
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(HideUnreachablePaths && isa<UnreachableInst>(TI)) ||
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(HideDeoptimizePaths && Node->getTerminatingDeoptimizeCall());
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return;
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}
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isHiddenBasicBlock[Node] =
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llvm::all_of(successors(Node), [this](const BasicBlock *BB) {
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return isHiddenBasicBlock[BB];
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});
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};
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/// The post order traversal iteration is done to know the status of
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/// isHiddenBasicBlock for all the successors on the current BB.
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for_each(po_begin(&F->getEntryBlock()), po_end(&F->getEntryBlock()),
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evaluateBB);
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}
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bool DOTGraphTraits<DOTFuncInfo *>::isNodeHidden(const BasicBlock *Node,
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const DOTFuncInfo *CFGInfo) {
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// If both restricting flags are false, all nodes are displayed.
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if (!HideUnreachablePaths && !HideDeoptimizePaths)
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return false;
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if (isHiddenBasicBlock.find(Node) == isHiddenBasicBlock.end())
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computeHiddenNodes(Node->getParent());
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return isHiddenBasicBlock[Node];
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}
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