tools/bugpoint/BugDriver.cpp

   1 //===- BugDriver.cpp - Top-Level BugPoint class implementation ------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This class contains all of the shared state and information that is used by
  10 // the BugPoint tool to track down errors in optimizations.  This class is the
  11 // main driver class that invokes all sub-functionality.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "BugDriver.h"
  16 #include "ToolRunner.h"
  17 #include "llvm/IR/Module.h"
  18 #include "llvm/IR/Verifier.h"
  19 #include "llvm/IRReader/IRReader.h"
  20 #include "llvm/Linker/Linker.h"
  21 #include "llvm/Pass.h"
  22 #include "llvm/Support/CommandLine.h"
  23 #include "llvm/Support/FileUtilities.h"
  24 #include "llvm/Support/Host.h"
  25 #include "llvm/Support/SourceMgr.h"
  26 #include "llvm/Support/raw_ostream.h"
  27 #include <memory>
  28 using namespace llvm;
  29
  30 namespace llvm {
  31 Triple TargetTriple;
  32 }
  33
  34 DiscardTemp::~DiscardTemp() {
  35   if (SaveTemps) {
  36     if (Error E = File.keep())
  37       errs() << "Failed to keep temp file " << toString(std::move(E)) << '\n';
  38     return;
  39   }
  40   if (Error E = File.discard())
  41     errs() << "Failed to delete temp file " << toString(std::move(E)) << '\n';
  42 }
  43
  44 // Anonymous namespace to define command line options for debugging.
  45 //
  46 namespace {
  47 // Output - The user can specify a file containing the expected output of the
  48 // program.  If this filename is set, it is used as the reference diff source,
  49 // otherwise the raw input run through an interpreter is used as the reference
  50 // source.
  51 //
  52 cl::opt<std::string> OutputFile("output",
  53                                 cl::desc("Specify a reference program output "
  54                                          "(for miscompilation detection)"));
  55 }
  56
  57 /// If we reduce or update the program somehow, call this method to update
  58 /// bugdriver with it.  This deletes the old module and sets the specified one
  59 /// as the current program.
  60 void BugDriver::setNewProgram(std::unique_ptr<Module> M) {
  61   Program = std::move(M);
  62 }
  63
  64 /// getPassesString - Turn a list of passes into a string which indicates the
  65 /// command line options that must be passed to add the passes.
  66 ///
  67 std::string llvm::getPassesString(const std::vector<std::string> &Passes) {
  68   std::string Result;
  69   for (unsigned i = 0, e = Passes.size(); i != e; ++i) {
  70     if (i)
  71       Result += " ";
  72     Result += "-";
  73     Result += Passes[i];
  74   }
  75   return Result;
  76 }
  77
  78 BugDriver::BugDriver(const char *toolname, bool find_bugs, unsigned timeout,
  79                      unsigned memlimit, bool use_valgrind, LLVMContext &ctxt)
  80     : Context(ctxt), ToolName(toolname), ReferenceOutputFile(OutputFile),
  81       Program(nullptr), Interpreter(nullptr), SafeInterpreter(nullptr),
  82       cc(nullptr), run_find_bugs(find_bugs), Timeout(timeout),
  83       MemoryLimit(memlimit), UseValgrind(use_valgrind) {}
  84
  85 BugDriver::~BugDriver() {
  86   if (Interpreter != SafeInterpreter)
  87     delete Interpreter;
  88   delete SafeInterpreter;
  89   delete cc;
  90 }
  91
  92 std::unique_ptr<Module> llvm::parseInputFile(StringRef Filename,
  93                                              LLVMContext &Ctxt) {
  94   SMDiagnostic Err;
  95   std::unique_ptr<Module> Result = parseIRFile(Filename, Err, Ctxt);
  96   if (!Result) {
  97     Err.print("bugpoint", errs());
  98     return Result;
  99   }
 100
 101   if (verifyModule(*Result, &errs())) {
 102     errs() << "bugpoint: " << Filename << ": error: input module is broken!\n";
 103     return std::unique_ptr<Module>();
 104   }
 105
 106   // If we don't have an override triple, use the first one to configure
 107   // bugpoint, or use the host triple if none provided.
 108   if (TargetTriple.getTriple().empty()) {
 109     Triple TheTriple(Result->getTargetTriple());
 110
 111     if (TheTriple.getTriple().empty())
 112       TheTriple.setTriple(sys::getDefaultTargetTriple());
 113
 114     TargetTriple.setTriple(TheTriple.getTriple());
 115   }
 116
 117   Result->setTargetTriple(TargetTriple.getTriple()); // override the triple
 118   return Result;
 119 }
 120
 121 std::unique_ptr<Module> BugDriver::swapProgramIn(std::unique_ptr<Module> M) {
 122   std::unique_ptr<Module> OldProgram = std::move(Program);
 123   Program = std::move(M);
 124   return OldProgram;
 125 }
 126
 127 // This method takes the specified list of LLVM input files, attempts to load
 128 // them, either as assembly or bitcode, then link them together. It returns
 129 // true on failure (if, for example, an input bitcode file could not be
 130 // parsed), and false on success.
 131 //
 132 bool BugDriver::addSources(const std::vector<std::string> &Filenames) {
 133   assert(!Program && "Cannot call addSources multiple times!");
 134   assert(!Filenames.empty() && "Must specify at least on input filename!");
 135
 136   // Load the first input file.
 137   Program = parseInputFile(Filenames[0], Context);
 138   if (!Program)
 139     return true;
 140
 141   outs() << "Read input file      : '" << Filenames[0] << "'\n";
 142
 143   for (unsigned i = 1, e = Filenames.size(); i != e; ++i) {
 144     std::unique_ptr<Module> M = parseInputFile(Filenames[i], Context);
 145     if (!M.get())
 146       return true;
 147
 148     outs() << "Linking in input file: '" << Filenames[i] << "'\n";
 149     if (Linker::linkModules(*Program, std::move(M)))
 150       return true;
 151   }
 152
 153   outs() << "*** All input ok\n";
 154
 155   // All input files read successfully!
 156   return false;
 157 }
 158
 159 /// run - The top level method that is invoked after all of the instance
 160 /// variables are set up from command line arguments.
 161 ///
 162 Error BugDriver::run() {
 163   if (run_find_bugs) {
 164     // Rearrange the passes and apply them to the program. Repeat this process
 165     // until the user kills the program or we find a bug.
 166     return runManyPasses(PassesToRun);
 167   }
 168
 169   // If we're not running as a child, the first thing that we must do is
 170   // determine what the problem is. Does the optimization series crash the
 171   // compiler, or does it produce illegal code?  We make the top-level
 172   // decision by trying to run all of the passes on the input program,
 173   // which should generate a bitcode file.  If it does generate a bitcode
 174   // file, then we know the compiler didn't crash, so try to diagnose a
 175   // miscompilation.
 176   if (!PassesToRun.empty()) {
 177     outs() << "Running selected passes on program to test for crash: ";
 178     if (runPasses(*Program, PassesToRun))
 179       return debugOptimizerCrash();
 180   }
 181
 182   // Set up the execution environment, selecting a method to run LLVM bitcode.
 183   if (Error E = initializeExecutionEnvironment())
 184     return E;
 185
 186   // Test to see if we have a code generator crash.
 187   outs() << "Running the code generator to test for a crash: ";
 188   if (Error E = compileProgram(*Program)) {
 189     outs() << toString(std::move(E));
 190     return debugCodeGeneratorCrash();
 191   }
 192   outs() << '\n';
 193
 194   // Run the raw input to see where we are coming from.  If a reference output
 195   // was specified, make sure that the raw output matches it.  If not, it's a
 196   // problem in the front-end or the code generator.
 197   //
 198   bool CreatedOutput = false;
 199   if (ReferenceOutputFile.empty()) {
 200     outs() << "Generating reference output from raw program: ";
 201     if (Error E = createReferenceFile(*Program)) {
 202       errs() << toString(std::move(E));
 203       return debugCodeGeneratorCrash();
 204     }
 205     CreatedOutput = true;
 206   }
 207
 208   // Make sure the reference output file gets deleted on exit from this
 209   // function, if appropriate.
 210   std::string ROF(ReferenceOutputFile);
 211   FileRemover RemoverInstance(ROF, CreatedOutput && !SaveTemps);
 212
 213   // Diff the output of the raw program against the reference output.  If it
 214   // matches, then we assume there is a miscompilation bug and try to
 215   // diagnose it.
 216   outs() << "*** Checking the code generator...\n";
 217   Expected<bool> Diff = diffProgram(*Program, "", "", false);
 218   if (Error E = Diff.takeError()) {
 219     errs() << toString(std::move(E));
 220     return debugCodeGeneratorCrash();
 221   }
 222   if (!*Diff) {
 223     outs() << "\n*** Output matches: Debugging miscompilation!\n";
 224     if (Error E = debugMiscompilation()) {
 225       errs() << toString(std::move(E));
 226       return debugCodeGeneratorCrash();
 227     }
 228     return Error::success();
 229   }
 230
 231   outs() << "\n*** Input program does not match reference diff!\n";
 232   outs() << "Debugging code generator problem!\n";
 233   if (Error E = debugCodeGenerator()) {
 234     errs() << toString(std::move(E));
 235     return debugCodeGeneratorCrash();
 236   }
 237   return Error::success();
 238 }
 239
 240 void llvm::PrintFunctionList(const std::vector<Function *> &Funcs) {
 241   unsigned NumPrint = Funcs.size();
 242   if (NumPrint > 10)
 243     NumPrint = 10;
 244   for (unsigned i = 0; i != NumPrint; ++i)
 245     outs() << " " << Funcs[i]->getName();
 246   if (NumPrint < Funcs.size())
 247     outs() << "... <" << Funcs.size() << " total>";
 248   outs().flush();
 249 }
 250
 251 void llvm::PrintGlobalVariableList(const std::vector<GlobalVariable *> &GVs) {
 252   unsigned NumPrint = GVs.size();
 253   if (NumPrint > 10)
 254     NumPrint = 10;
 255   for (unsigned i = 0; i != NumPrint; ++i)
 256     outs() << " " << GVs[i]->getName();
 257   if (NumPrint < GVs.size())
 258     outs() << "... <" << GVs.size() << " total>";
 259   outs().flush();
 260 }