//===-- Debug.cpp - An easy way to add debug output to your code ----------===//

//

// 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 file implements a handy way of adding debugging information to your

// code, without it being enabled all of the time, and without having to add

// command line options to enable it.

//

// In particular, just wrap your code with the LLVM_DEBUG() macro, and it will

// be enabled automatically if you specify '-debug' on the command-line.

// Alternatively, you can also use the SET_DEBUG_TYPE("foo") macro to specify

// that your debug code belongs to class "foo".  Then, on the command line, you

// can specify '-debug-only=foo' to enable JUST the debug information for the

// foo class.

//

// When compiling without assertions, the -debug-* options and all code in

// LLVM_DEBUG() statements disappears, so it does not affect the runtime of the

// code.

//

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

#include "llvm/Support/Debug.h"

#include "llvm/Support/CommandLine.h"

#include "llvm/Support/ManagedStatic.h"

#include "llvm/Support/Signals.h"

#include "llvm/Support/circular_raw_ostream.h"

#include "llvm/Support/raw_ostream.h"

#undef isCurrentDebugType

#undef setCurrentDebugType

#undef setCurrentDebugTypes

using namespace llvm;

// Even though LLVM might be built with NDEBUG, define symbols that the code

// built without NDEBUG can depend on via the llvm/Support/Debug.h header.

namespace llvm {

/// Exported boolean set by the -debug option.

bool DebugFlag = false;

static ManagedStatic<std::vector<std::string>> CurrentDebugType;

/// Return true if the specified string is the debug type

/// specified on the command line, or if none was specified on the command line

/// with the -debug-only=X option.

bool isCurrentDebugType(const char *DebugType) {

  if (CurrentDebugType->empty())

    return true;

  // See if DebugType is in list. Note: do not use find() as that forces us to

  // unnecessarily create an std::string instance.

  for (auto &d : *CurrentDebugType) {

    if (d == DebugType)

      return true;

  }

  return false;

}

/// Set the current debug type, as if the -debug-only=X

/// option were specified.  Note that DebugFlag also needs to be set to true for

/// debug output to be produced.

///

void setCurrentDebugTypes(const char **Types, unsigned Count);

void setCurrentDebugType(const char *Type) {

  setCurrentDebugTypes(&Type, 1);

}

void setCurrentDebugTypes(const char **Types, unsigned Count) {

  CurrentDebugType->clear();

  for (size_t T = 0; T < Count; ++T)

    CurrentDebugType->push_back(Types[T]);

}

} // namespace llvm

// All Debug.h functionality is a no-op in NDEBUG mode.

#ifndef NDEBUG

// -debug - Command line option to enable the DEBUG statements in the passes.

// This flag may only be enabled in debug builds.

static cl::opt<bool, true>

Debug("debug", cl::desc("Enable debug output"), cl::Hidden,

      cl::location(DebugFlag));

// -debug-buffer-size - Buffer the last N characters of debug output

//until program termination.

static cl::opt<unsigned>

DebugBufferSize("debug-buffer-size",

                cl::desc("Buffer the last N characters of debug output "

                         "until program termination. "

                         "[default 0 -- immediate print-out]"),

                cl::Hidden,

                cl::init(0));

namespace {

struct DebugOnlyOpt {

  void operator=(const std::string &Val) const {

    if (Val.empty())

      return;

    DebugFlag = true;

    SmallVector<StringRef,8> dbgTypes;

    StringRef(Val).split(dbgTypes, ',', -1, false);

    for (auto dbgType : dbgTypes)

      CurrentDebugType->push_back(std::string(dbgType));

  }

};

}

static DebugOnlyOpt DebugOnlyOptLoc;

static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >

DebugOnly("debug-only", cl::desc("Enable a specific type of debug output (comma separated list of types)"),

          cl::Hidden, cl::ZeroOrMore, cl::value_desc("debug string"),

          cl::location(DebugOnlyOptLoc), cl::ValueRequired);

// Signal handlers - dump debug output on termination.

static void debug_user_sig_handler(void *Cookie) {

  // This is a bit sneaky.  Since this is under #ifndef NDEBUG, we

  // know that debug mode is enabled and dbgs() really is a

  // circular_raw_ostream.  If NDEBUG is defined, then dbgs() ==

  // errs() but this will never be invoked.

  llvm::circular_raw_ostream &dbgout =

      static_cast<circular_raw_ostream &>(llvm::dbgs());

  dbgout.flushBufferWithBanner();

}

/// dbgs - Return a circular-buffered debug stream.

raw_ostream &llvm::dbgs() {

  // Do one-time initialization in a thread-safe way.

  static struct dbgstream {

    circular_raw_ostream strm;

    dbgstream() :

        strm(errs(), "*** Debug Log Output ***\n",

             (!EnableDebugBuffering || !DebugFlag) ? 0 : DebugBufferSize) {

      if (EnableDebugBuffering && DebugFlag && DebugBufferSize != 0)

        // TODO: Add a handler for SIGUSER1-type signals so the user can

        // force a debug dump.

        sys::AddSignalHandler(&debug_user_sig_handler, nullptr);

      // Otherwise we've already set the debug stream buffer size to

      // zero, disabling buffering so it will output directly to errs().

    }

  } thestrm;

  return thestrm.strm;

}

#else

// Avoid "has no symbols" warning.

namespace llvm {

  /// dbgs - Return errs().

  raw_ostream &dbgs() {

    return errs();

  }

}

#endif

/// EnableDebugBuffering - Turn on signal handler installation.

///

bool llvm::EnableDebugBuffering = false;