//===- 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" #include namespace llvm { class StringRef; class Twine; /// An error handler callback. typedef void (*fatal_error_handler_t)(void *user_data, const std::string& 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 exit(1), it /// does not return. LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const char *reason, bool gen_crash_diag = true); LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const std::string &reason, bool gen_crash_diag = true); LLVM_ATTRIBUTE_NORETURN void report_fatal_error(StringRef reason, bool gen_crash_diag = true); LLVM_ATTRIBUTE_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 is expected to return, e.g. the user /// defined error handler throws an exception. /// /// 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), then a bad_alloc exception /// is thrown, if LLVM is compiled with exception support, otherwise an /// assertion is called. 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. LLVM_ATTRIBUTE_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, becomes an optimizer hint that the current location /// is not supposed to be reachable. On compilers that don't support /// such hints, prints a reduced message instead. /// /// Use this instead of assert(0). It conveys intent more clearly and /// allows compilers to omit some 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_BUILTIN_UNREACHABLE #else #define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal() #endif #endif