1//===- llvm/Support/ErrorHandling.h - Fatal error handling ------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines an API used to indicate fatal error conditions. Non-fatal 11// errors (most of them) should be handled through LLVMContext. 12// 13//===----------------------------------------------------------------------===// 14 15#ifndef LLVM_SUPPORT_ERRORHANDLING_H 16#define LLVM_SUPPORT_ERRORHANDLING_H 17 18#include "llvm/Support/Compiler.h" 19#include <string> 20 21namespace llvm { 22class StringRef; 23 class Twine; 24 25 /// An error handler callback. 26 typedef void (*fatal_error_handler_t)(void *user_data, 27 const std::string& reason, 28 bool gen_crash_diag); 29 30 /// install_fatal_error_handler - Installs a new error handler to be used 31 /// whenever a serious (non-recoverable) error is encountered by LLVM. 32 /// 33 /// If no error handler is installed the default is to print the error message 34 /// to stderr, and call exit(1). If an error handler is installed then it is 35 /// the handler's responsibility to log the message, it will no longer be 36 /// printed to stderr. If the error handler returns, then exit(1) will be 37 /// called. 38 /// 39 /// It is dangerous to naively use an error handler which throws an exception. 40 /// Even though some applications desire to gracefully recover from arbitrary 41 /// faults, blindly throwing exceptions through unfamiliar code isn't a way to 42 /// achieve this. 43 /// 44 /// \param user_data - An argument which will be passed to the install error 45 /// handler. 46 void install_fatal_error_handler(fatal_error_handler_t handler, 47 void *user_data = nullptr); 48 49 /// Restores default error handling behaviour. 50 void remove_fatal_error_handler(); 51 52 /// ScopedFatalErrorHandler - This is a simple helper class which just 53 /// calls install_fatal_error_handler in its constructor and 54 /// remove_fatal_error_handler in its destructor. 55 struct ScopedFatalErrorHandler { 56 explicit ScopedFatalErrorHandler(fatal_error_handler_t handler, 57 void *user_data = nullptr) { 58 install_fatal_error_handler(handler, user_data); 59 } 60 61 ~ScopedFatalErrorHandler() { remove_fatal_error_handler(); } 62 }; 63 64/// Reports a serious error, calling any installed error handler. These 65/// functions are intended to be used for error conditions which are outside 66/// the control of the compiler (I/O errors, invalid user input, etc.) 67/// 68/// If no error handler is installed the default is to print the message to 69/// standard error, followed by a newline. 70/// After the error handler is called this function will call exit(1), it 71/// does not return. 72LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const char *reason, 73 bool gen_crash_diag = true); 74LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const std::string &reason, 75 bool gen_crash_diag = true); 76LLVM_ATTRIBUTE_NORETURN void report_fatal_error(StringRef reason, 77 bool gen_crash_diag = true); 78LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const Twine &reason, 79 bool gen_crash_diag = true); 80 81 /// This function calls abort(), and prints the optional message to stderr. 82 /// Use the llvm_unreachable macro (that adds location info), instead of 83 /// calling this function directly. 84 LLVM_ATTRIBUTE_NORETURN void 85 llvm_unreachable_internal(const char *msg=nullptr, const char *file=nullptr, 86 unsigned line=0); 87} 88 89/// Marks that the current location is not supposed to be reachable. 90/// In !NDEBUG builds, prints the message and location info to stderr. 91/// In NDEBUG builds, becomes an optimizer hint that the current location 92/// is not supposed to be reachable. On compilers that don't support 93/// such hints, prints a reduced message instead. 94/// 95/// Use this instead of assert(0). It conveys intent more clearly and 96/// allows compilers to omit some unnecessary code. 97#ifndef NDEBUG 98#define llvm_unreachable(msg) \ 99 ::llvm::llvm_unreachable_internal(msg, __FILE__, __LINE__) 100#elif defined(LLVM_BUILTIN_UNREACHABLE) 101#define llvm_unreachable(msg) LLVM_BUILTIN_UNREACHABLE 102#else 103#define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal() 104#endif 105 106#endif 107