| //===- CFGPrinter.cpp - DOT printer for the control flow graph ------------===// |
| // |
| // 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 defines a `-dot-cfg` analysis pass, which emits the |
| // `<prefix>.<fnname>.dot` file for each function in the program, with a graph |
| // of the CFG for that function. The default value for `<prefix>` is `cfg` but |
| // can be customized as needed. |
| // |
| // The other main feature of this file is that it implements the |
| // Function::viewCFG method, which is useful for debugging passes which operate |
| // on the CFG. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Analysis/CFGPrinter.h" |
| #include "llvm/ADT/PostOrderIterator.h" |
| #include "llvm/InitializePasses.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/FileSystem.h" |
| #include "llvm/Support/GraphWriter.h" |
| |
| using namespace llvm; |
| |
| static cl::opt<std::string> |
| CFGFuncName("cfg-func-name", cl::Hidden, |
| cl::desc("The name of a function (or its substring)" |
| " whose CFG is viewed/printed.")); |
| |
| static cl::opt<std::string> CFGDotFilenamePrefix( |
| "cfg-dot-filename-prefix", cl::Hidden, |
| cl::desc("The prefix used for the CFG dot file names.")); |
| |
| static cl::opt<bool> HideUnreachablePaths("cfg-hide-unreachable-paths", |
| cl::init(false)); |
| |
| static cl::opt<bool> HideDeoptimizePaths("cfg-hide-deoptimize-paths", |
| cl::init(false)); |
| |
| static cl::opt<double> HideColdPaths( |
| "cfg-hide-cold-paths", cl::init(0.0), |
| cl::desc("Hide blocks with relative frequency below the given value")); |
| |
| static cl::opt<bool> ShowHeatColors("cfg-heat-colors", cl::init(true), |
| cl::Hidden, |
| cl::desc("Show heat colors in CFG")); |
| |
| static cl::opt<bool> UseRawEdgeWeight("cfg-raw-weights", cl::init(false), |
| cl::Hidden, |
| cl::desc("Use raw weights for labels. " |
| "Use percentages as default.")); |
| |
| static cl::opt<bool> |
| ShowEdgeWeight("cfg-weights", cl::init(false), cl::Hidden, |
| cl::desc("Show edges labeled with weights")); |
| |
| static void writeCFGToDotFile(Function &F, BlockFrequencyInfo *BFI, |
| BranchProbabilityInfo *BPI, uint64_t MaxFreq, |
| bool CFGOnly = false) { |
| std::string Filename = |
| (CFGDotFilenamePrefix + "." + F.getName() + ".dot").str(); |
| errs() << "Writing '" << Filename << "'..."; |
| |
| std::error_code EC; |
| raw_fd_ostream File(Filename, EC, sys::fs::OF_Text); |
| |
| DOTFuncInfo CFGInfo(&F, BFI, BPI, MaxFreq); |
| CFGInfo.setHeatColors(ShowHeatColors); |
| CFGInfo.setEdgeWeights(ShowEdgeWeight); |
| CFGInfo.setRawEdgeWeights(UseRawEdgeWeight); |
| |
| if (!EC) |
| WriteGraph(File, &CFGInfo, CFGOnly); |
| else |
| errs() << " error opening file for writing!"; |
| errs() << "\n"; |
| } |
| |
| static void viewCFG(Function &F, const BlockFrequencyInfo *BFI, |
| const BranchProbabilityInfo *BPI, uint64_t MaxFreq, |
| bool CFGOnly = false) { |
| DOTFuncInfo CFGInfo(&F, BFI, BPI, MaxFreq); |
| CFGInfo.setHeatColors(ShowHeatColors); |
| CFGInfo.setEdgeWeights(ShowEdgeWeight); |
| CFGInfo.setRawEdgeWeights(UseRawEdgeWeight); |
| |
| ViewGraph(&CFGInfo, "cfg." + F.getName(), CFGOnly); |
| } |
| |
| namespace { |
| struct CFGViewerLegacyPass : public FunctionPass { |
| static char ID; // Pass identifcation, replacement for typeid |
| CFGViewerLegacyPass() : FunctionPass(ID) { |
| initializeCFGViewerLegacyPassPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| bool runOnFunction(Function &F) override { |
| if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) |
| return false; |
| auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI(); |
| auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI(); |
| viewCFG(F, BFI, BPI, getMaxFreq(F, BFI)); |
| return false; |
| } |
| |
| void print(raw_ostream &OS, const Module * = nullptr) const override {} |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| FunctionPass::getAnalysisUsage(AU); |
| AU.addRequired<BlockFrequencyInfoWrapperPass>(); |
| AU.addRequired<BranchProbabilityInfoWrapperPass>(); |
| AU.setPreservesAll(); |
| } |
| }; |
| } // namespace |
| |
| char CFGViewerLegacyPass::ID = 0; |
| INITIALIZE_PASS(CFGViewerLegacyPass, "view-cfg", "View CFG of function", false, |
| true) |
| |
| PreservedAnalyses CFGViewerPass::run(Function &F, FunctionAnalysisManager &AM) { |
| if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) |
| return PreservedAnalyses::all(); |
| auto *BFI = &AM.getResult<BlockFrequencyAnalysis>(F); |
| auto *BPI = &AM.getResult<BranchProbabilityAnalysis>(F); |
| viewCFG(F, BFI, BPI, getMaxFreq(F, BFI)); |
| return PreservedAnalyses::all(); |
| } |
| |
| namespace { |
| struct CFGOnlyViewerLegacyPass : public FunctionPass { |
| static char ID; // Pass identifcation, replacement for typeid |
| CFGOnlyViewerLegacyPass() : FunctionPass(ID) { |
| initializeCFGOnlyViewerLegacyPassPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| bool runOnFunction(Function &F) override { |
| if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) |
| return false; |
| auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI(); |
| auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI(); |
| viewCFG(F, BFI, BPI, getMaxFreq(F, BFI), /*CFGOnly=*/true); |
| return false; |
| } |
| |
| void print(raw_ostream &OS, const Module * = nullptr) const override {} |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| FunctionPass::getAnalysisUsage(AU); |
| AU.addRequired<BlockFrequencyInfoWrapperPass>(); |
| AU.addRequired<BranchProbabilityInfoWrapperPass>(); |
| AU.setPreservesAll(); |
| } |
| }; |
| } // namespace |
| |
| char CFGOnlyViewerLegacyPass::ID = 0; |
| INITIALIZE_PASS(CFGOnlyViewerLegacyPass, "view-cfg-only", |
| "View CFG of function (with no function bodies)", false, true) |
| |
| PreservedAnalyses CFGOnlyViewerPass::run(Function &F, |
| FunctionAnalysisManager &AM) { |
| if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) |
| return PreservedAnalyses::all(); |
| auto *BFI = &AM.getResult<BlockFrequencyAnalysis>(F); |
| auto *BPI = &AM.getResult<BranchProbabilityAnalysis>(F); |
| viewCFG(F, BFI, BPI, getMaxFreq(F, BFI), /*CFGOnly=*/true); |
| return PreservedAnalyses::all(); |
| } |
| |
| namespace { |
| struct CFGPrinterLegacyPass : public FunctionPass { |
| static char ID; // Pass identification, replacement for typeid |
| CFGPrinterLegacyPass() : FunctionPass(ID) { |
| initializeCFGPrinterLegacyPassPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| bool runOnFunction(Function &F) override { |
| if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) |
| return false; |
| auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI(); |
| auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI(); |
| writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI)); |
| return false; |
| } |
| |
| void print(raw_ostream &OS, const Module * = nullptr) const override {} |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| FunctionPass::getAnalysisUsage(AU); |
| AU.addRequired<BlockFrequencyInfoWrapperPass>(); |
| AU.addRequired<BranchProbabilityInfoWrapperPass>(); |
| AU.setPreservesAll(); |
| } |
| }; |
| } // namespace |
| |
| char CFGPrinterLegacyPass::ID = 0; |
| INITIALIZE_PASS(CFGPrinterLegacyPass, "dot-cfg", |
| "Print CFG of function to 'dot' file", false, true) |
| |
| PreservedAnalyses CFGPrinterPass::run(Function &F, |
| FunctionAnalysisManager &AM) { |
| if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) |
| return PreservedAnalyses::all(); |
| auto *BFI = &AM.getResult<BlockFrequencyAnalysis>(F); |
| auto *BPI = &AM.getResult<BranchProbabilityAnalysis>(F); |
| writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI)); |
| return PreservedAnalyses::all(); |
| } |
| |
| namespace { |
| struct CFGOnlyPrinterLegacyPass : public FunctionPass { |
| static char ID; // Pass identification, replacement for typeid |
| CFGOnlyPrinterLegacyPass() : FunctionPass(ID) { |
| initializeCFGOnlyPrinterLegacyPassPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| bool runOnFunction(Function &F) override { |
| if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) |
| return false; |
| auto *BPI = &getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI(); |
| auto *BFI = &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI(); |
| writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI), /*CFGOnly=*/true); |
| return false; |
| } |
| void print(raw_ostream &OS, const Module * = nullptr) const override {} |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| FunctionPass::getAnalysisUsage(AU); |
| AU.addRequired<BlockFrequencyInfoWrapperPass>(); |
| AU.addRequired<BranchProbabilityInfoWrapperPass>(); |
| AU.setPreservesAll(); |
| } |
| }; |
| } // namespace |
| |
| char CFGOnlyPrinterLegacyPass::ID = 0; |
| INITIALIZE_PASS(CFGOnlyPrinterLegacyPass, "dot-cfg-only", |
| "Print CFG of function to 'dot' file (with no function bodies)", |
| false, true) |
| |
| PreservedAnalyses CFGOnlyPrinterPass::run(Function &F, |
| FunctionAnalysisManager &AM) { |
| if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) |
| return PreservedAnalyses::all(); |
| auto *BFI = &AM.getResult<BlockFrequencyAnalysis>(F); |
| auto *BPI = &AM.getResult<BranchProbabilityAnalysis>(F); |
| writeCFGToDotFile(F, BFI, BPI, getMaxFreq(F, BFI), /*CFGOnly=*/true); |
| return PreservedAnalyses::all(); |
| } |
| |
| /// viewCFG - This function is meant for use from the debugger. You can just |
| /// say 'call F->viewCFG()' and a ghostview window should pop up from the |
| /// program, displaying the CFG of the current function. This depends on there |
| /// being a 'dot' and 'gv' program in your path. |
| /// |
| void Function::viewCFG() const { viewCFG(false, nullptr, nullptr); } |
| |
| void Function::viewCFG(bool ViewCFGOnly, const BlockFrequencyInfo *BFI, |
| const BranchProbabilityInfo *BPI) const { |
| if (!CFGFuncName.empty() && !getName().contains(CFGFuncName)) |
| return; |
| DOTFuncInfo CFGInfo(this, BFI, BPI, BFI ? getMaxFreq(*this, BFI) : 0); |
| ViewGraph(&CFGInfo, "cfg" + getName(), ViewCFGOnly); |
| } |
| |
| /// viewCFGOnly - This function is meant for use from the debugger. It works |
| /// just like viewCFG, but it does not include the contents of basic blocks |
| /// into the nodes, just the label. If you are only interested in the CFG |
| /// this can make the graph smaller. |
| /// |
| void Function::viewCFGOnly() const { viewCFGOnly(nullptr, nullptr); } |
| |
| void Function::viewCFGOnly(const BlockFrequencyInfo *BFI, |
| const BranchProbabilityInfo *BPI) const { |
| viewCFG(true, BFI, BPI); |
| } |
| |
| FunctionPass *llvm::createCFGPrinterLegacyPassPass() { |
| return new CFGPrinterLegacyPass(); |
| } |
| |
| FunctionPass *llvm::createCFGOnlyPrinterLegacyPassPass() { |
| return new CFGOnlyPrinterLegacyPass(); |
| } |
| |
| /// Find all blocks on the paths which terminate with a deoptimize or |
| /// unreachable (i.e. all blocks which are post-dominated by a deoptimize |
| /// or unreachable). These paths are hidden if the corresponding cl::opts |
| /// are enabled. |
| void DOTGraphTraits<DOTFuncInfo *>::computeDeoptOrUnreachablePaths( |
| const Function *F) { |
| auto evaluateBB = [&](const BasicBlock *Node) { |
| if (succ_empty(Node)) { |
| const Instruction *TI = Node->getTerminator(); |
| isOnDeoptOrUnreachablePath[Node] = |
| (HideUnreachablePaths && isa<UnreachableInst>(TI)) || |
| (HideDeoptimizePaths && Node->getTerminatingDeoptimizeCall()); |
| return; |
| } |
| isOnDeoptOrUnreachablePath[Node] = |
| llvm::all_of(successors(Node), [this](const BasicBlock *BB) { |
| return isOnDeoptOrUnreachablePath[BB]; |
| }); |
| }; |
| /// The post order traversal iteration is done to know the status of |
| /// isOnDeoptOrUnreachablePath for all the successors on the current BB. |
| llvm::for_each(post_order(&F->getEntryBlock()), evaluateBB); |
| } |
| |
| bool DOTGraphTraits<DOTFuncInfo *>::isNodeHidden(const BasicBlock *Node, |
| const DOTFuncInfo *CFGInfo) { |
| if (HideColdPaths.getNumOccurrences() > 0) |
| if (auto *BFI = CFGInfo->getBFI()) { |
| uint64_t NodeFreq = BFI->getBlockFreq(Node).getFrequency(); |
| uint64_t EntryFreq = BFI->getEntryFreq(); |
| // Hide blocks with relative frequency below HideColdPaths threshold. |
| if ((double)NodeFreq / EntryFreq < HideColdPaths) |
| return true; |
| } |
| if (HideUnreachablePaths || HideDeoptimizePaths) { |
| if (!isOnDeoptOrUnreachablePath.contains(Node)) |
| computeDeoptOrUnreachablePaths(Node->getParent()); |
| return isOnDeoptOrUnreachablePath[Node]; |
| } |
| return false; |
| } |