//===-- cc1_main.cpp - Clang CC1 Compiler Frontend ------------------------===//

//

// 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 is the entry point to the clang -cc1 functionality, which implements the

// core compiler functionality along with a number of additional tools for

// demonstration and testing purposes.

//

//===----------------------------------------------------------------------===//

#include "clang/Basic/Stack.h"

#include "clang/Basic/TargetOptions.h"

#include "clang/CodeGen/ObjectFilePCHContainerOperations.h"

#include "clang/Config/config.h"

#include "clang/Driver/DriverDiagnostic.h"

#include "clang/Driver/Options.h"

#include "clang/Frontend/CompilerInstance.h"

#include "clang/Frontend/CompilerInvocation.h"

#include "clang/Frontend/FrontendDiagnostic.h"

#include "clang/Frontend/TextDiagnosticBuffer.h"

#include "clang/Frontend/TextDiagnosticPrinter.h"

#include "clang/Frontend/Utils.h"

#include "clang/FrontendTool/Utils.h"

#include "llvm/ADT/Statistic.h"

#include "llvm/Config/llvm-config.h"

#include "llvm/LinkAllPasses.h"

#include "llvm/MC/TargetRegistry.h"

#include "llvm/Option/Arg.h"

#include "llvm/Option/ArgList.h"

#include "llvm/Option/OptTable.h"

#include "llvm/Support/BuryPointer.h"

#include "llvm/Support/Compiler.h"

#include "llvm/Support/ErrorHandling.h"

#include "llvm/Support/ManagedStatic.h"

#include "llvm/Support/Path.h"

#include "llvm/Support/Process.h"

#include "llvm/Support/Signals.h"

#include "llvm/Support/TargetSelect.h"

#include "llvm/Support/TimeProfiler.h"

#include "llvm/Support/Timer.h"

#include "llvm/Support/raw_ostream.h"

#include "llvm/Target/TargetMachine.h"

#include <cstdio>

#ifdef CLANG_HAVE_RLIMITS

#include <sys/resource.h>

#endif

using namespace clang;

using namespace llvm::opt;

//===----------------------------------------------------------------------===//

// Main driver

//===----------------------------------------------------------------------===//

static void LLVMErrorHandler(void *UserData, const char *Message,

                             bool GenCrashDiag) {

  DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);

  Diags.Report(diag::err_fe_error_backend) << Message;

  // Run the interrupt handlers to make sure any special cleanups get done, in

  // particular that we remove files registered with RemoveFileOnSignal.

  llvm::sys::RunInterruptHandlers();

  // We cannot recover from llvm errors.  When reporting a fatal error, exit

  // with status 70 to generate crash diagnostics.  For BSD systems this is

  // defined as an internal software error.  Otherwise, exit with status 1.

  llvm::sys::Process::Exit(GenCrashDiag ? 70 : 
10
);

}

#ifdef CLANG_HAVE_RLIMITS

#if defined(__linux__) && defined(__PIE__)

static size_t getCurrentStackAllocation() {

  // If we can't compute the current stack usage, allow for 512K of command

  // line arguments and environment.

  size_t Usage = 512 * 1024;

  if (FILE *StatFile = fopen("/proc/self/stat", "r")) {

    // We assume that the stack extends from its current address to the end of

    // the environment space. In reality, there is another string literal (the

    // program name) after the environment, but this is close enough (we only

    // need to be within 100K or so).

    unsigned long StackPtr, EnvEnd;

    // Disable silly GCC -Wformat warning that complains about length

    // modifiers on ignored format specifiers. We want to retain these

    // for documentation purposes even though they have no effect.

#if defined(__GNUC__) && !defined(__clang__)

#pragma GCC diagnostic push

#pragma GCC diagnostic ignored "-Wformat"

#endif

    if (fscanf(StatFile,

               "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*lu %*lu %*lu %*lu %*lu "

               "%*lu %*ld %*ld %*ld %*ld %*ld %*ld %*llu %*lu %*ld %*lu %*lu "

               "%*lu %*lu %lu %*lu %*lu %*lu %*lu %*lu %*llu %*lu %*lu %*d %*d "

               "%*u %*u %*llu %*lu %*ld %*lu %*lu %*lu %*lu %*lu %*lu %lu %*d",

               &StackPtr, &EnvEnd) == 2) {

#if defined(__GNUC__) && !defined(__clang__)

#pragma GCC diagnostic pop

#endif

      Usage = StackPtr < EnvEnd ? EnvEnd - StackPtr : StackPtr - EnvEnd;

    }

    fclose(StatFile);

  }

  return Usage;

}

#include <alloca.h>

LLVM_ATTRIBUTE_NOINLINE

static void ensureStackAddressSpace() {

  // Linux kernels prior to 4.1 will sometimes locate the heap of a PIE binary

  // relatively close to the stack (they are only guaranteed to be 128MiB

  // apart). This results in crashes if we happen to heap-allocate more than

  // 128MiB before we reach our stack high-water mark.

  //

  // To avoid these crashes, ensure that we have sufficient virtual memory

  // pages allocated before we start running.

  size_t Curr = getCurrentStackAllocation();

  const int kTargetStack = DesiredStackSize - 256 * 1024;

  if (Curr < kTargetStack) {

    volatile char *volatile Alloc =

        static_cast<volatile char *>(alloca(kTargetStack - Curr));

    Alloc[0] = 0;

    Alloc[kTargetStack - Curr - 1] = 0;

  }

}

#else

static void ensureStackAddressSpace() {}

#endif

/// Attempt to ensure that we have at least 8MiB of usable stack space.

static void ensureSufficientStack() {

  struct rlimit rlim;

  if (getrlimit(RLIMIT_STACK, &rlim) != 0)

    return;

  // Increase the soft stack limit to our desired level, if necessary and

  // possible.

  if (rlim.rlim_cur != RLIM_INFINITY &&

      rlim.rlim_cur < rlim_t(DesiredStackSize)) {

    // Try to allocate sufficient stack.

    if (rlim.rlim_max == RLIM_INFINITY ||

        rlim.rlim_max >= rlim_t(DesiredStackSize))

      rlim.rlim_cur = DesiredStackSize;

    else if (rlim.rlim_cur == rlim.rlim_max)

      return;

    else

      rlim.rlim_cur = rlim.rlim_max;

    if (setrlimit(RLIMIT_STACK, &rlim) != 0 ||

        rlim.rlim_cur != DesiredStackSize)

      return;

  }

  // We should now have a stack of size at least DesiredStackSize. Ensure

  // that we can actually use that much, if necessary.

  ensureStackAddressSpace();

}

#else

static void ensureSufficientStack() {}

#endif

/// Print supported cpus of the given target.

static int PrintSupportedCPUs(std::string TargetStr) {

  std::string Error;

  const llvm::Target *TheTarget =

      llvm::TargetRegistry::lookupTarget(TargetStr, Error);

  if (!TheTarget) {

    llvm::errs() << Error;

    return 1;

  }

  // the target machine will handle the mcpu printing

  llvm::TargetOptions Options;

  std::unique_ptr<llvm::TargetMachine> TheTargetMachine(

      TheTarget->createTargetMachine(TargetStr, "", "+cpuhelp", Options, None));

  return 0;

}

int cc1_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {

  ensureSufficientStack();

  std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());

  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());

  // Register the support for object-file-wrapped Clang modules.

  auto PCHOps = Clang->getPCHContainerOperations();

  PCHOps->registerWriter(std::make_unique<ObjectFilePCHContainerWriter>());

  PCHOps->registerReader(std::make_unique<ObjectFilePCHContainerReader>());

  // Initialize targets first, so that --version shows registered targets.

  llvm::InitializeAllTargets();

  llvm::InitializeAllTargetMCs();

  llvm::InitializeAllAsmPrinters();

  llvm::InitializeAllAsmParsers();

  // Buffer diagnostics from argument parsing so that we can output them using a

  // well formed diagnostic object.

  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();

  TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer;

  DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagsBuffer);

  // Setup round-trip remarks for the DiagnosticsEngine used in CreateFromArgs.

  if (find(Argv, StringRef("-Rround-trip-cc1-args")) != Argv.end())

    Diags.setSeverity(diag::remark_cc1_round_trip_generated,

                      diag::Severity::Remark, {});

  bool Success = CompilerInvocation::CreateFromArgs(Clang->getInvocation(),

                                                    Argv, Diags, Argv0);

  if (Clang->getFrontendOpts().TimeTrace ||

      
!Clang->getFrontendOpts().TimeTracePath.empty()41.5k
) {

    Clang->getFrontendOpts().TimeTrace = 1;

    llvm::timeTraceProfilerInitialize(

        Clang->getFrontendOpts().TimeTraceGranularity, Argv0);

  }

  // --print-supported-cpus takes priority over the actual compilation.

  if (Clang->getFrontendOpts().PrintSupportedCPUs)

    return PrintSupportedCPUs(Clang->getTargetOpts().Triple);

  // Infer the builtin include path if unspecified.

  if (Clang->getHeaderSearchOpts().UseBuiltinIncludes &&

      
Clang->getHeaderSearchOpts().ResourceDir.empty()41.5k
)

    Clang->getHeaderSearchOpts().ResourceDir =

      CompilerInvocation::GetResourcesPath(Argv0, MainAddr);

  // Create the actual diagnostics engine.

  Clang->createDiagnostics();

  if (!Clang->hasDiagnostics())

    return 1;

  // Set an error handler, so that any LLVM backend diagnostics go through our

  // error handler.

  llvm::install_fatal_error_handler(LLVMErrorHandler,

                                  static_cast<void*>(&Clang->getDiagnostics()));

  DiagsBuffer->FlushDiagnostics(Clang->getDiagnostics());

  if (!Success) {

    Clang->getDiagnosticClient().finish();

    return 1;

  }

  // Execute the frontend actions.

  {

    llvm::TimeTraceScope TimeScope("ExecuteCompiler");

    Success = ExecuteCompilerInvocation(Clang.get());

  }

  // If any timers were active but haven't been destroyed yet, print their

  // results now.  This happens in -disable-free mode.

  llvm::TimerGroup::printAll(llvm::errs());

  llvm::TimerGroup::clearAll();

  if (llvm::timeTraceProfilerEnabled()) {

    SmallString<128> Path(Clang->getFrontendOpts().OutputFile);

    llvm::sys::path::replace_extension(Path, "json");

    if (!Clang->getFrontendOpts().TimeTracePath.empty()) {

      // replace the suffix to '.json' directly

      SmallString<128> TracePath(Clang->getFrontendOpts().TimeTracePath);

      if (llvm::sys::fs::is_directory(TracePath))

        llvm::sys::path::append(TracePath, llvm::sys::path::filename(Path));

      Path.assign(TracePath);

    }

    if (auto profilerOutput = Clang->createOutputFile(

            Path.str(), /*Binary=*/false, /*RemoveFileOnSignal=*/false,

            /*useTemporary=*/false)) {

      llvm::timeTraceProfilerWrite(*profilerOutput);

      profilerOutput.reset();

      llvm::timeTraceProfilerCleanup();

      Clang->clearOutputFiles(false);

    }

  }

  // Our error handler depends on the Diagnostics object, which we're

  // potentially about to delete. Uninstall the handler now so that any

  // later errors use the default handling behavior instead.

  llvm::remove_fatal_error_handler();

  // When running with -disable-free, don't do any destruction or shutdown.

  if (Clang->getFrontendOpts().DisableFree) {

    llvm::BuryPointer(std::move(Clang));

    return !Success;

  }

  return !Success;

}