BugDriver.h

//===- BugDriver.h - Top-Level BugPoint class -------------------*- C++ -*-===//
//
// 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 class contains all of the shared state and information that is used by
// the BugPoint tool to track down errors in optimizations.  This class is the
// main driver class that invokes all sub-functionality.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_TOOLS_BUGPOINT_BUGDRIVER_H
#define LLVM_TOOLS_BUGPOINT_BUGDRIVER_H

#include "llvm/IR/ValueMap.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <memory>
#include <string>
#include <vector>

namespace llvm {

class Module;
class GlobalVariable;
class Function;
class BasicBlock;
class AbstractInterpreter;
class Instruction;
class LLVMContext;

class CC;

extern bool DisableSimplifyCFG;

/// BugpointIsInterrupted - Set to true when the user presses ctrl-c.
///
extern bool BugpointIsInterrupted;

class BugDriver {
  LLVMContext &Context;
  const char *ToolName;            // argv[0] of bugpoint
  std::string ReferenceOutputFile; // Name of `good' output file
  std::unique_ptr<Module> Program; // The raw program, linked together
  std::vector<std::string> PassesToRun;
  AbstractInterpreter *Interpreter;     // How to run the program
  AbstractInterpreter *SafeInterpreter; // To generate reference output, etc.
  CC *cc;
  bool run_find_bugs;
  unsigned Timeout;
  unsigned MemoryLimit;
  bool UseValgrind;

  // FIXME: sort out public/private distinctions...
  friend class ReducePassList;
  friend class ReduceMisCodegenFunctions;

public:
  BugDriver(const char *toolname, bool find_bugs, unsigned timeout,
            unsigned memlimit, bool use_valgrind, LLVMContext &ctxt);
  ~BugDriver();

  const char *getToolName() const { return ToolName; }

  LLVMContext &getContext() const { return Context; }

  // Set up methods... these methods are used to copy information about the
  // command line arguments into instance variables of BugDriver.
  //
  bool addSources(const std::vector<std::string> &FileNames);
  void addPass(std::string p) { PassesToRun.push_back(std::move(p)); }
  void setPassesToRun(const std::vector<std::string> &PTR) {
    PassesToRun = PTR;
  }
  const std::vector<std::string> &getPassesToRun() const { return PassesToRun; }

  /// run - The top level method that is invoked after all of the instance
  /// variables are set up from command line arguments. The \p as_child argument
  /// indicates whether the driver is to run in parent mode or child mode.
  ///
  Error run();

  /// debugOptimizerCrash - This method is called when some optimizer pass
  /// crashes on input.  It attempts to prune down the testcase to something
  /// reasonable, and figure out exactly which pass is crashing.
  ///
  Error debugOptimizerCrash(const std::string &ID = "passes");

  /// debugCodeGeneratorCrash - This method is called when the code generator
  /// crashes on an input.  It attempts to reduce the input as much as possible
  /// while still causing the code generator to crash.
  Error debugCodeGeneratorCrash();

  /// debugMiscompilation - This method is used when the passes selected are not
  /// crashing, but the generated output is semantically different from the
  /// input.
  Error debugMiscompilation();

  /// compileSharedObject - This method creates a SharedObject from a given
  /// BitcodeFile for debugging a code generator.
  ///
  Expected<std::string> compileSharedObject(const std::string &BitcodeFile);

  /// debugCodeGenerator - This method narrows down a module to a function or
  /// set of functions, using the CBE as a ``safe'' code generator for other
  /// functions that are not under consideration.
  Error debugCodeGenerator();

  /// isExecutingJIT - Returns true if bugpoint is currently testing the JIT
  ///
  bool isExecutingJIT();

  Module &getProgram() const { return *Program; }

  /// Set the current module to the specified module, returning the old one.
  std::unique_ptr<Module> swapProgramIn(std::unique_ptr<Module> M);

  AbstractInterpreter *switchToSafeInterpreter() {
    AbstractInterpreter *Old = Interpreter;
    Interpreter = (AbstractInterpreter *)SafeInterpreter;
    return Old;
  }

  void switchToInterpreter(AbstractInterpreter *AI) { Interpreter = AI; }

  /// If we reduce or update the program somehow, call this method to update
  /// bugdriver with it.  This deletes the old module and sets the specified one
  /// as the current program.
  void setNewProgram(std::unique_ptr<Module> M);

  /// Try to compile the specified module. This is used for code generation
  /// crash testing.
  Error compileProgram(Module &M) const;

  /// This method runs "Program", capturing the output of the program to a file.
  /// A recommended filename may be optionally specified.
  Expected<std::string> executeProgram(const Module &Program,
                                       std::string OutputFilename,
                                       std::string Bitcode,
                                       const std::string &SharedObjects,
                                       AbstractInterpreter *AI) const;

  /// Used to create reference output with the "safe" backend, if reference
  /// output is not provided.  If there is a problem with the code generator
  /// (e.g., llc crashes), this will return false and set Error.
  Expected<std::string>
  executeProgramSafely(const Module &Program,
                       const std::string &OutputFile) const;

  /// Calls compileProgram and then records the output into ReferenceOutputFile.
  /// Returns true if reference file created, false otherwise. Note:
  /// initializeExecutionEnvironment should be called BEFORE this function.
  Error createReferenceFile(Module &M, const std::string &Filename =
                                           "bugpoint.reference.out-%%%%%%%");

  /// This method executes the specified module and diffs the output against the
  /// file specified by ReferenceOutputFile.  If the output is different, 1 is
  /// returned.  If there is a problem with the code generator (e.g., llc
  /// crashes), this will return -1 and set Error.
  Expected<bool> diffProgram(const Module &Program,
                             const std::string &BitcodeFile = "",
                             const std::string &SharedObj = "",
                             bool RemoveBitcode = false) const;

  /// This function is used to output M to a file named "bugpoint-ID.bc".
  void EmitProgressBitcode(const Module &M, const std::string &ID,
                           bool NoFlyer = false) const;

  /// This method clones the current Program and deletes the specified
  /// instruction from the cloned module.  It then runs a series of cleanup
  /// passes (ADCE and SimplifyCFG) to eliminate any code which depends on the
  /// value. The modified module is then returned.
  ///
  std::unique_ptr<Module> deleteInstructionFromProgram(const Instruction *I,
                                                       unsigned Simp);

  /// This method clones the current Program and performs a series of cleanups
  /// intended to get rid of extra cruft on the module. If the
  /// MayModifySemantics argument is true, then the cleanups is allowed to
  /// modify how the code behaves.
  ///
  std::unique_ptr<Module> performFinalCleanups(std::unique_ptr<Module> M,
                                               bool MayModifySemantics = false);

  /// Given a module, extract up to one loop from it into a new function. This
  /// returns null if there are no extractable loops in the program or if the
  /// loop extractor crashes.
  std::unique_ptr<Module> extractLoop(Module *M);

  /// Extract all but the specified basic blocks into their own functions. The
  /// only detail is that M is actually a module cloned from the one the BBs are
  /// in, so some mapping needs to be performed. If this operation fails for
  /// some reason (ie the implementation is buggy), this function should return
  /// null, otherwise it returns a new Module.
  std::unique_ptr<Module>
  extractMappedBlocksFromModule(const std::vector<BasicBlock *> &BBs,
                                Module *M);

  /// Carefully run the specified set of pass on the specified/ module,
  /// returning the transformed module on success, or a null pointer on failure.
  std::unique_ptr<Module> runPassesOn(Module *M,
                                      const std::vector<std::string> &Passes,
                                      ArrayRef<std::string> ExtraArgs = {});

  /// runPasses - Run the specified passes on Program, outputting a bitcode
  /// file and writting the filename into OutputFile if successful.  If the
  /// optimizations fail for some reason (optimizer crashes), return true,
  /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
  /// deleted on success, and the filename string is undefined.  This prints to
  /// outs() a single line message indicating whether compilation was successful
  /// or failed, unless Quiet is set.  ExtraArgs specifies additional arguments
  /// to pass to the child bugpoint instance.
  ///
  bool runPasses(Module &Program, const std::vector<std::string> &PassesToRun,
                 std::string &OutputFilename, bool DeleteOutput = false,
                 bool Quiet = false,
                 ArrayRef<std::string> ExtraArgs = {}) const;

  /// runPasses - Just like the method above, but this just returns true or
  /// false indicating whether or not the optimizer crashed on the specified
  /// input (true = crashed).  Does not produce any output.
  ///
  bool runPasses(Module &M, const std::vector<std::string> &PassesToRun) const {
    std::string Filename;
    return runPasses(M, PassesToRun, Filename, true);
  }

  /// Take the specified pass list and create different combinations of passes
  /// to compile the program with. Compile the program with each set and mark
  /// test to see if it compiled correctly. If the passes compiled correctly
  /// output nothing and rearrange the passes into a new order. If the passes
  /// did not compile correctly, output the command required to recreate the
  /// failure.
  Error runManyPasses(const std::vector<std::string> &AllPasses);

  /// This writes the current "Program" to the named bitcode file.  If an error
  /// occurs, true is returned.
  bool writeProgramToFile(const std::string &Filename, const Module &M) const;
  bool writeProgramToFile(const std::string &Filename, int FD,
                          const Module &M) const;
  bool writeProgramToFile(int FD, const Module &M) const;

private:
  /// initializeExecutionEnvironment - This method is used to set up the
  /// environment for executing LLVM programs.
  ///
  Error initializeExecutionEnvironment();
};

struct DiscardTemp {
  sys::fs::TempFile &File;
  ~DiscardTemp();
};

///  Given a bitcode or assembly input filename, parse and return it, or return
///  null if not possible.
///
std::unique_ptr<Module> parseInputFile(StringRef InputFilename,
                                       LLVMContext &ctxt);

/// getPassesString - Turn a list of passes into a string which indicates the
/// command line options that must be passed to add the passes.
///
std::string getPassesString(const std::vector<std::string> &Passes);

/// PrintFunctionList - prints out list of problematic functions
///
void PrintFunctionList(const std::vector<Function *> &Funcs);

/// PrintGlobalVariableList - prints out list of problematic global variables
///
void PrintGlobalVariableList(const std::vector<GlobalVariable *> &GVs);

// DeleteGlobalInitializer - "Remove" the global variable by deleting its
// initializer, making it external.
//
void DeleteGlobalInitializer(GlobalVariable *GV);

// DeleteFunctionBody - "Remove" the function by deleting all of it's basic
// blocks, making it external.
//
void DeleteFunctionBody(Function *F);

/// Given a module and a list of functions in the module, split the functions
/// OUT of the specified module, and place them in the new module.
std::unique_ptr<Module>
SplitFunctionsOutOfModule(Module *M, const std::vector<Function *> &F,
                          ValueToValueMapTy &VMap);

} // End llvm namespace

#endif