CFGPrinter.cpp revision 353358
1193323Sed//===- CFGPrinter.cpp - DOT printer for the control flow graph ------------===// 2193323Sed// 3353358Sdim// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4353358Sdim// See https://llvm.org/LICENSE.txt for license information. 5353358Sdim// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6193323Sed// 7193323Sed//===----------------------------------------------------------------------===// 8193323Sed// 9344779Sdim// This file defines a `-dot-cfg` analysis pass, which emits the 10344779Sdim// `<prefix>.<fnname>.dot` file for each function in the program, with a graph 11344779Sdim// of the CFG for that function. The default value for `<prefix>` is `cfg` but 12344779Sdim// can be customized as needed. 13193323Sed// 14193323Sed// The other main feature of this file is that it implements the 15193323Sed// Function::viewCFG method, which is useful for debugging passes which operate 16193323Sed// on the CFG. 17193323Sed// 18193323Sed//===----------------------------------------------------------------------===// 19193323Sed 20198396Srdivacky#include "llvm/Analysis/CFGPrinter.h" 21193323Sed#include "llvm/Pass.h" 22276479Sdim#include "llvm/Support/FileSystem.h" 23193323Sedusing namespace llvm; 24193323Sed 25341825Sdimstatic cl::opt<std::string> CFGFuncName( 26341825Sdim "cfg-func-name", cl::Hidden, 27341825Sdim cl::desc("The name of a function (or its substring)" 28341825Sdim " whose CFG is viewed/printed.")); 29341825Sdim 30344779Sdimstatic cl::opt<std::string> CFGDotFilenamePrefix( 31344779Sdim "cfg-dot-filename-prefix", cl::Hidden, 32344779Sdim cl::desc("The prefix used for the CFG dot file names.")); 33344779Sdim 34193323Sednamespace { 35314564Sdim struct CFGViewerLegacyPass : public FunctionPass { 36193323Sed static char ID; // Pass identifcation, replacement for typeid 37314564Sdim CFGViewerLegacyPass() : FunctionPass(ID) { 38314564Sdim initializeCFGViewerLegacyPassPass(*PassRegistry::getPassRegistry()); 39218893Sdim } 40193323Sed 41276479Sdim bool runOnFunction(Function &F) override { 42193323Sed F.viewCFG(); 43193323Sed return false; 44193323Sed } 45193323Sed 46276479Sdim void print(raw_ostream &OS, const Module* = nullptr) const override {} 47193323Sed 48276479Sdim void getAnalysisUsage(AnalysisUsage &AU) const override { 49193323Sed AU.setPreservesAll(); 50193323Sed } 51193323Sed }; 52193323Sed} 53193323Sed 54314564Sdimchar CFGViewerLegacyPass::ID = 0; 55314564SdimINITIALIZE_PASS(CFGViewerLegacyPass, "view-cfg", "View CFG of function", false, true) 56193323Sed 57314564SdimPreservedAnalyses CFGViewerPass::run(Function &F, 58314564Sdim FunctionAnalysisManager &AM) { 59314564Sdim F.viewCFG(); 60314564Sdim return PreservedAnalyses::all(); 61314564Sdim} 62314564Sdim 63314564Sdim 64193323Sednamespace { 65314564Sdim struct CFGOnlyViewerLegacyPass : public FunctionPass { 66193323Sed static char ID; // Pass identifcation, replacement for typeid 67314564Sdim CFGOnlyViewerLegacyPass() : FunctionPass(ID) { 68314564Sdim initializeCFGOnlyViewerLegacyPassPass(*PassRegistry::getPassRegistry()); 69218893Sdim } 70193323Sed 71276479Sdim bool runOnFunction(Function &F) override { 72198090Srdivacky F.viewCFGOnly(); 73193323Sed return false; 74193323Sed } 75193323Sed 76276479Sdim void print(raw_ostream &OS, const Module* = nullptr) const override {} 77193323Sed 78276479Sdim void getAnalysisUsage(AnalysisUsage &AU) const override { 79193323Sed AU.setPreservesAll(); 80193323Sed } 81193323Sed }; 82193323Sed} 83193323Sed 84314564Sdimchar CFGOnlyViewerLegacyPass::ID = 0; 85314564SdimINITIALIZE_PASS(CFGOnlyViewerLegacyPass, "view-cfg-only", 86218893Sdim "View CFG of function (with no function bodies)", false, true) 87193323Sed 88314564SdimPreservedAnalyses CFGOnlyViewerPass::run(Function &F, 89314564Sdim FunctionAnalysisManager &AM) { 90314564Sdim F.viewCFGOnly(); 91314564Sdim return PreservedAnalyses::all(); 92314564Sdim} 93314564Sdim 94327952Sdimstatic void writeCFGToDotFile(Function &F, bool CFGOnly = false) { 95341825Sdim if (!CFGFuncName.empty() && !F.getName().contains(CFGFuncName)) 96341825Sdim return; 97344779Sdim std::string Filename = 98344779Sdim (CFGDotFilenamePrefix + "." + F.getName() + ".dot").str(); 99314564Sdim errs() << "Writing '" << Filename << "'..."; 100314564Sdim 101314564Sdim std::error_code EC; 102314564Sdim raw_fd_ostream File(Filename, EC, sys::fs::F_Text); 103314564Sdim 104314564Sdim if (!EC) 105327952Sdim WriteGraph(File, (const Function*)&F, CFGOnly); 106314564Sdim else 107314564Sdim errs() << " error opening file for writing!"; 108314564Sdim errs() << "\n"; 109314564Sdim} 110314564Sdim 111193323Sednamespace { 112314564Sdim struct CFGPrinterLegacyPass : public FunctionPass { 113193323Sed static char ID; // Pass identification, replacement for typeid 114314564Sdim CFGPrinterLegacyPass() : FunctionPass(ID) { 115314564Sdim initializeCFGPrinterLegacyPassPass(*PassRegistry::getPassRegistry()); 116218893Sdim } 117193323Sed 118276479Sdim bool runOnFunction(Function &F) override { 119314564Sdim writeCFGToDotFile(F); 120193323Sed return false; 121193323Sed } 122193323Sed 123276479Sdim void print(raw_ostream &OS, const Module* = nullptr) const override {} 124193323Sed 125276479Sdim void getAnalysisUsage(AnalysisUsage &AU) const override { 126193323Sed AU.setPreservesAll(); 127193323Sed } 128193323Sed }; 129193323Sed} 130193323Sed 131314564Sdimchar CFGPrinterLegacyPass::ID = 0; 132341825SdimINITIALIZE_PASS(CFGPrinterLegacyPass, "dot-cfg", "Print CFG of function to 'dot' file", 133218893Sdim false, true) 134193323Sed 135314564SdimPreservedAnalyses CFGPrinterPass::run(Function &F, 136314564Sdim FunctionAnalysisManager &AM) { 137314564Sdim writeCFGToDotFile(F); 138314564Sdim return PreservedAnalyses::all(); 139314564Sdim} 140314564Sdim 141193323Sednamespace { 142314564Sdim struct CFGOnlyPrinterLegacyPass : public FunctionPass { 143193323Sed static char ID; // Pass identification, replacement for typeid 144314564Sdim CFGOnlyPrinterLegacyPass() : FunctionPass(ID) { 145314564Sdim initializeCFGOnlyPrinterLegacyPassPass(*PassRegistry::getPassRegistry()); 146218893Sdim } 147276479Sdim 148276479Sdim bool runOnFunction(Function &F) override { 149327952Sdim writeCFGToDotFile(F, /*CFGOnly=*/true); 150193323Sed return false; 151193323Sed } 152276479Sdim void print(raw_ostream &OS, const Module* = nullptr) const override {} 153193323Sed 154276479Sdim void getAnalysisUsage(AnalysisUsage &AU) const override { 155193323Sed AU.setPreservesAll(); 156193323Sed } 157193323Sed }; 158193323Sed} 159193323Sed 160314564Sdimchar CFGOnlyPrinterLegacyPass::ID = 0; 161314564SdimINITIALIZE_PASS(CFGOnlyPrinterLegacyPass, "dot-cfg-only", 162212904Sdim "Print CFG of function to 'dot' file (with no function bodies)", 163218893Sdim false, true) 164193323Sed 165314564SdimPreservedAnalyses CFGOnlyPrinterPass::run(Function &F, 166314564Sdim FunctionAnalysisManager &AM) { 167327952Sdim writeCFGToDotFile(F, /*CFGOnly=*/true); 168314564Sdim return PreservedAnalyses::all(); 169314564Sdim} 170314564Sdim 171193323Sed/// viewCFG - This function is meant for use from the debugger. You can just 172193323Sed/// say 'call F->viewCFG()' and a ghostview window should pop up from the 173193323Sed/// program, displaying the CFG of the current function. This depends on there 174193323Sed/// being a 'dot' and 'gv' program in your path. 175193323Sed/// 176193323Sedvoid Function::viewCFG() const { 177341825Sdim if (!CFGFuncName.empty() && !getName().contains(CFGFuncName)) 178341825Sdim return; 179234353Sdim ViewGraph(this, "cfg" + getName()); 180193323Sed} 181193323Sed 182193323Sed/// viewCFGOnly - This function is meant for use from the debugger. It works 183193323Sed/// just like viewCFG, but it does not include the contents of basic blocks 184276479Sdim/// into the nodes, just the label. If you are only interested in the CFG 185276479Sdim/// this can make the graph smaller. 186193323Sed/// 187193323Sedvoid Function::viewCFGOnly() const { 188341825Sdim if (!CFGFuncName.empty() && !getName().contains(CFGFuncName)) 189341825Sdim return; 190234353Sdim ViewGraph(this, "cfg" + getName(), true); 191193323Sed} 192193323Sed 193314564SdimFunctionPass *llvm::createCFGPrinterLegacyPassPass () { 194314564Sdim return new CFGPrinterLegacyPass(); 195193323Sed} 196193323Sed 197314564SdimFunctionPass *llvm::createCFGOnlyPrinterLegacyPassPass () { 198314564Sdim return new CFGOnlyPrinterLegacyPass(); 199193323Sed} 200193323Sed 201