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/ADT/StringRef.h" 19 #include "llvm/Support/Compiler.h" 20 #include <string> 21 22 namespace llvm { 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 you are using llvm_start_multithreaded, you should register the handler 34 /// before doing that. 35 /// 36 /// If no error handler is installed the default is to print the error message 37 /// to stderr, and call exit(1). If an error handler is installed then it is 38 /// the handler's responsibility to log the message, it will no longer be 39 /// printed to stderr. If the error handler returns, then exit(1) will be 40 /// called. 41 /// 42 /// It is dangerous to naively use an error handler which throws an exception. 43 /// Even though some applications desire to gracefully recover from arbitrary 44 /// faults, blindly throwing exceptions through unfamiliar code isn't a way to 45 /// achieve this. 46 /// 47 /// \param user_data - An argument which will be passed to the install error 48 /// handler. 49 void install_fatal_error_handler(fatal_error_handler_t handler, 50 void *user_data = 0); 51 52 /// Restores default error handling behaviour. 53 /// This must not be called between llvm_start_multithreaded() and 54 /// llvm_stop_multithreaded(). 55 void remove_fatal_error_handler(); 56 57 /// ScopedFatalErrorHandler - This is a simple helper class which just 58 /// calls install_fatal_error_handler in its constructor and 59 /// remove_fatal_error_handler in its destructor. 60 struct ScopedFatalErrorHandler { 61 explicit ScopedFatalErrorHandler(fatal_error_handler_t handler, 62 void *user_data = 0) { 63 install_fatal_error_handler(handler, user_data); 64 } 65 66 ~ScopedFatalErrorHandler() { remove_fatal_error_handler(); } 67 }; 68 69 /// Reports a serious error, calling any installed error handler. These 70 /// functions are intended to be used for error conditions which are outside 71 /// the control of the compiler (I/O errors, invalid user input, etc.) 72 /// 73 /// If no error handler is installed the default is to print the message to 74 /// standard error, followed by a newline. 75 /// After the error handler is called this function will call exit(1), it 76 /// does not return. 77 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const char *reason, 78 bool gen_crash_diag = true); 79 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const std::string &reason, 80 bool gen_crash_diag = true); 81 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(StringRef reason, 82 bool gen_crash_diag = true); 83 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const Twine &reason, 84 bool gen_crash_diag = true); 85 86 /// This function calls abort(), and prints the optional message to stderr. 87 /// Use the llvm_unreachable macro (that adds location info), instead of 88 /// calling this function directly. 89 LLVM_ATTRIBUTE_NORETURN void llvm_unreachable_internal(const char *msg=0, 90 const char *file=0, 91 unsigned line=0); 92 } 93 94 /// Marks that the current location is not supposed to be reachable. 95 /// In !NDEBUG builds, prints the message and location info to stderr. 96 /// In NDEBUG builds, becomes an optimizer hint that the current location 97 /// is not supposed to be reachable. On compilers that don't support 98 /// such hints, prints a reduced message instead. 99 /// 100 /// Use this instead of assert(0). It conveys intent more clearly and 101 /// allows compilers to omit some unnecessary code. 102 #ifndef NDEBUG 103 #define llvm_unreachable(msg) \ 104 ::llvm::llvm_unreachable_internal(msg, __FILE__, __LINE__) 105 #elif defined(LLVM_BUILTIN_UNREACHABLE) 106 #define llvm_unreachable(msg) LLVM_BUILTIN_UNREACHABLE 107 #else 108 #define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal() 109 #endif 110 111 #endif 112
