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Diffstat (limited to 'contrib/llvm-project/llvm/lib/Analysis/CFGPrinter.cpp')
| -rw-r--r-- | contrib/llvm-project/llvm/lib/Analysis/CFGPrinter.cpp | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/Analysis/CFGPrinter.cpp b/contrib/llvm-project/llvm/lib/Analysis/CFGPrinter.cpp new file mode 100644 index 000000000000..67a15197058b --- /dev/null +++ b/contrib/llvm-project/llvm/lib/Analysis/CFGPrinter.cpp @@ -0,0 +1,200 @@ +//===- 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/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); +} + +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(); +} + +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(); +} + +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(); +} + +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); +} + +/// 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()) { + BlockFrequency NodeFreq = BFI->getBlockFreq(Node); + BlockFrequency EntryFreq = BFI->getEntryFreq(); + // Hide blocks with relative frequency below HideColdPaths threshold. + if ((double)NodeFreq.getFrequency() / EntryFreq.getFrequency() < + HideColdPaths) + return true; + } + if (HideUnreachablePaths || HideDeoptimizePaths) { + if (!isOnDeoptOrUnreachablePath.contains(Node)) + computeDeoptOrUnreachablePaths(Node->getParent()); + return isOnDeoptOrUnreachablePath[Node]; + } + return false; +} |