Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- llvm/Support/ErrorHandling.h - Fatal error handling ------*- 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 file defines an API used to indicate fatal error conditions.  Non-fatal

// errors (most of them) should be handled through LLVMContext.

//

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

#ifndef LLVM_SUPPORT_ERRORHANDLING_H

#define LLVM_SUPPORT_ERRORHANDLING_H

#include "llvm/Support/Compiler.h"

namespace llvm {

  class StringRef;

  class Twine;

  /// An error handler callback.

  typedef void (*fatal_error_handler_t)(void *user_data,

                                        const char *reason,

                                        bool gen_crash_diag);

  /// install_fatal_error_handler - Installs a new error handler to be used

  /// whenever a serious (non-recoverable) error is encountered by LLVM.

  ///

  /// If no error handler is installed the default is to print the error message

  /// to stderr, and call exit(1).  If an error handler is installed then it is

  /// the handler's responsibility to log the message, it will no longer be

  /// printed to stderr.  If the error handler returns, then exit(1) will be

  /// called.

  ///

  /// It is dangerous to naively use an error handler which throws an exception.

  /// Even though some applications desire to gracefully recover from arbitrary

  /// faults, blindly throwing exceptions through unfamiliar code isn't a way to

  /// achieve this.

  ///

  /// \param user_data - An argument which will be passed to the install error

  /// handler.

  void install_fatal_error_handler(fatal_error_handler_t handler,

                                   void *user_data = nullptr);

  /// Restores default error handling behaviour.

  void remove_fatal_error_handler();

  /// ScopedFatalErrorHandler - This is a simple helper class which just

  /// calls install_fatal_error_handler in its constructor and

  /// remove_fatal_error_handler in its destructor.

  struct ScopedFatalErrorHandler {

    explicit ScopedFatalErrorHandler(fatal_error_handler_t handler,

                                     void *user_data = nullptr) {

      install_fatal_error_handler(handler, user_data);

    }

    ~ScopedFatalErrorHandler() { remove_fatal_error_handler(); }

  };

/// Reports a serious error, calling any installed error handler. These

/// functions are intended to be used for error conditions which are outside

/// the control of the compiler (I/O errors, invalid user input, etc.)

///

/// If no error handler is installed the default is to print the message to

/// standard error, followed by a newline.

/// After the error handler is called this function will call abort(), it

/// does not return.

/// NOTE: The std::string variant was removed to avoid a <string> dependency.

[[noreturn]] void report_fatal_error(const char *reason,

                                     bool gen_crash_diag = true);

[[noreturn]] void report_fatal_error(StringRef reason,

                                     bool gen_crash_diag = true);

[[noreturn]] void report_fatal_error(const Twine &reason,

                                     bool gen_crash_diag = true);

/// Installs a new bad alloc error handler that should be used whenever a

/// bad alloc error, e.g. failing malloc/calloc, is encountered by LLVM.

///

/// The user can install a bad alloc handler, in order to define the behavior

/// in case of failing allocations, e.g. throwing an exception. Note that this

/// handler must not trigger any additional allocations itself.

///

/// If no error handler is installed the default is to print the error message

/// to stderr, and call exit(1).  If an error handler is installed then it is

/// the handler's responsibility to log the message, it will no longer be

/// printed to stderr.  If the error handler returns, then exit(1) will be

/// called.

///

///

/// \param user_data - An argument which will be passed to the installed error

/// handler.

void install_bad_alloc_error_handler(fatal_error_handler_t handler,

                                     void *user_data = nullptr);

/// Restores default bad alloc error handling behavior.

void remove_bad_alloc_error_handler();

void install_out_of_memory_new_handler();

/// Reports a bad alloc error, calling any user defined bad alloc

/// error handler. In contrast to the generic 'report_fatal_error'

/// functions, this function might not terminate, e.g. the user

/// defined error handler throws an exception, but it won't return.

///

/// Note: When throwing an exception in the bad alloc handler, make sure that

/// the following unwind succeeds, e.g. do not trigger additional allocations

/// in the unwind chain.

///

/// If no error handler is installed (default), throws a bad_alloc exception

/// if LLVM is compiled with exception support. Otherwise prints the error

/// to standard error and calls abort().

[[noreturn]] void report_bad_alloc_error(const char *Reason,

                                         bool GenCrashDiag = true);

/// This function calls abort(), and prints the optional message to stderr.

/// Use the llvm_unreachable macro (that adds location info), instead of

/// calling this function directly.

[[noreturn]] void

llvm_unreachable_internal(const char *msg = nullptr, const char *file = nullptr,

                          unsigned line = 0);

}

/// Marks that the current location is not supposed to be reachable.

/// In !NDEBUG builds, prints the message and location info to stderr.

/// In NDEBUG builds, if the platform does not support a builtin unreachable

/// then we call an internal LLVM runtime function. Otherwise the behavior is

/// controlled by the CMake flag

///   -DLLVM_UNREACHABLE_OPTIMIZE

/// * When "ON" (default) llvm_unreachable() becomes an optimizer hint

///   that the current location is not supposed to be reachable: the hint

///   turns such code path into undefined behavior.  On compilers that don't

///   support such hints, prints a reduced message instead and aborts the

///   program.

/// * When "OFF", a builtin_trap is emitted instead of an

//    optimizer hint or printing a reduced message.

///

/// Use this instead of assert(0). It conveys intent more clearly, suppresses

/// diagnostics for unreachable code paths, and allows compilers to omit

/// unnecessary code.

#ifndef NDEBUG

#define llvm_unreachable(msg) \

  ::llvm::llvm_unreachable_internal(msg, __FILE__, __LINE__)

#elif !defined(LLVM_BUILTIN_UNREACHABLE)

#define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal()

#elif LLVM_UNREACHABLE_OPTIMIZE

#define llvm_unreachable(msg) LLVM_BUILTIN_UNREACHABLE

#else

#define llvm_unreachable(msg)                                                  \

  do {                                                                         \

    LLVM_BUILTIN_TRAP;                                                         \

    LLVM_BUILTIN_UNREACHABLE;                                                  \

  } while (false)

#endif

#endif