//===- bugpoint.cpp - The LLVM Bugpoint utility ---------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This program is an automated compiler debugger tool.  It is used to narrow
// down miscompilations and crash problems to a specific pass in the compiler,
// and the specific Module or Function input that is causing the problem.
//
//===----------------------------------------------------------------------===//

#include "BugDriver.h"
#include "ToolRunner.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/LegacyPassNameParser.h"
#include "llvm/LinkAllIR.h"
#include "llvm/LinkAllPasses.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/PluginLoader.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/Valgrind.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"

//Enable this macro to debug bugpoint itself.
//#define DEBUG_BUGPOINT 1

using namespace llvm;

static cl::opt<bool>
FindBugs("find-bugs", cl::desc("Run many different optimization sequences "
                               "on program to find bugs"), cl::init(false));

static cl::list<std::string>
InputFilenames(cl::Positional, cl::OneOrMore,
               cl::desc("<input llvm ll/bc files>"));

static cl::opt<unsigned>
TimeoutValue("timeout", cl::init(300), cl::value_desc("seconds"),
             cl::desc("Number of seconds program is allowed to run before it "
                      "is killed (default is 300s), 0 disables timeout"));

static cl::opt<int>
MemoryLimit("mlimit", cl::init(-1), cl::value_desc("MBytes"),
            cl::desc("Maximum amount of memory to use. 0 disables check."
                     " Defaults to 400MB (800MB under valgrind)."));

static cl::opt<bool>
UseValgrind("enable-valgrind",
            cl::desc("Run optimizations through valgrind"));

// The AnalysesList is automatically populated with registered Passes by the
// PassNameParser.
//
static cl::list<const PassInfo*, bool, PassNameParser>
PassList(cl::desc("Passes available:"), cl::ZeroOrMore);

static cl::opt<bool>
StandardLinkOpts("std-link-opts",
                 cl::desc("Include the standard link time optimizations"));

static cl::opt<bool>
OptLevelO1("O1",
           cl::desc("Optimization level 1. Identical to 'opt -O1'"));

static cl::opt<bool>
OptLevelO2("O2",
           cl::desc("Optimization level 2. Identical to 'opt -O2'"));

static cl::opt<bool>
OptLevelO3("O3",
           cl::desc("Optimization level 3. Identical to 'opt -O3'"));

static cl::opt<std::string>
OverrideTriple("mtriple", cl::desc("Override target triple for module"));

/// BugpointIsInterrupted - Set to true when the user presses ctrl-c.
bool llvm::BugpointIsInterrupted = false;

#ifndef DEBUG_BUGPOINT
static void BugpointInterruptFunction() {
  BugpointIsInterrupted = true;
}
#endif

// Hack to capture a pass list.
namespace {
  class AddToDriver : public legacy::FunctionPassManager {
    BugDriver &D;
  public:
    AddToDriver(BugDriver &_D) : FunctionPassManager(nullptr), D(_D) {}

    void add(Pass *P) override {
      const void *ID = P->getPassID();
      const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(ID);
      D.addPass(PI->getPassArgument());
    }
  };
}

#ifdef LINK_POLLY_INTO_TOOLS
namespace polly {
void initializePollyPasses(llvm::PassRegistry &Registry);
}
#endif

int main(int argc, char **argv) {
#ifndef DEBUG_BUGPOINT
  llvm::sys::PrintStackTraceOnErrorSignal();
  llvm::PrettyStackTraceProgram X(argc, argv);
  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
#endif

  // Initialize passes
  PassRegistry &Registry = *PassRegistry::getPassRegistry();
  initializeCore(Registry);
  initializeScalarOpts(Registry);
  initializeObjCARCOpts(Registry);
  initializeVectorization(Registry);
  initializeIPO(Registry);
  initializeAnalysis(Registry);
  initializeTransformUtils(Registry);
  initializeInstCombine(Registry);
  initializeInstrumentation(Registry);
  initializeTarget(Registry);

#ifdef LINK_POLLY_INTO_TOOLS
  polly::initializePollyPasses(Registry);
#endif
  
  cl::ParseCommandLineOptions(argc, argv,
                              "LLVM automatic testcase reducer. See\nhttp://"
                              "llvm.org/cmds/bugpoint.html"
                              " for more information.\n");
#ifndef DEBUG_BUGPOINT
  sys::SetInterruptFunction(BugpointInterruptFunction);
#endif

  LLVMContext& Context = getGlobalContext();
  // If we have an override, set it and then track the triple we want Modules
  // to use.
  if (!OverrideTriple.empty()) {
    TargetTriple.setTriple(Triple::normalize(OverrideTriple));
    outs() << "Override triple set to '" << TargetTriple.getTriple() << "'\n";
  }

  if (MemoryLimit < 0) {
    // Set the default MemoryLimit.  Be sure to update the flag's description if
    // you change this.
    if (sys::RunningOnValgrind() || UseValgrind)
      MemoryLimit = 800;
    else
      MemoryLimit = 400;
  }

  BugDriver D(argv[0], FindBugs, TimeoutValue, MemoryLimit,
              UseValgrind, Context);
  if (D.addSources(InputFilenames)) return 1;

  AddToDriver PM(D);

  if (StandardLinkOpts) {
    PassManagerBuilder Builder;
    Builder.Inliner = createFunctionInliningPass();
    Builder.populateLTOPassManager(PM);
  }

  if (OptLevelO1 || OptLevelO2 || OptLevelO3) {
    PassManagerBuilder Builder;
    if (OptLevelO1)
      Builder.Inliner = createAlwaysInlinerPass();
    else if (OptLevelO2)
      Builder.Inliner = createFunctionInliningPass(225);
    else
      Builder.Inliner = createFunctionInliningPass(275);
    Builder.populateFunctionPassManager(PM);
    Builder.populateModulePassManager(PM);
  }

  for (const PassInfo *PI : PassList)
    D.addPass(PI->getPassArgument());

  // Bugpoint has the ability of generating a plethora of core files, so to
  // avoid filling up the disk, we prevent it
#ifndef DEBUG_BUGPOINT
  sys::Process::PreventCoreFiles();
#endif

  std::string Error;
  bool Failure = D.run(Error);
  if (!Error.empty()) {
    errs() << Error;
    return 1;
  }
  return Failure;
}