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 "llvm/ADT/StringRef.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 29 /// install_fatal_error_handler - Installs a new error handler to be used 30 /// whenever a serious (non-recoverable) error is encountered by LLVM. 31 /// 32 /// If you are using llvm_start_multithreaded, you should register the handler 33 /// before doing that. 34 /// 35 /// If no error handler is installed the default is to print the error message 36 /// to stderr, and call exit(1). If an error handler is installed then it is 37 /// the handler's responsibility to log the message, it will no longer be 38 /// printed to stderr. If the error handler returns, then exit(1) will be 39 /// called. 40 /// 41 /// It is dangerous to naively use an error handler which throws an exception. 42 /// Even though some applications desire to gracefully recover from arbitrary 43 /// faults, blindly throwing exceptions through unfamiliar code isn't a way to 44 /// achieve this. 45 /// 46 /// \param user_data - An argument which will be passed to the install error 47 /// handler. 48 void install_fatal_error_handler(fatal_error_handler_t handler, 49 void *user_data = 0); 50 51 /// Restores default error handling behaviour. 52 /// This must not be called between llvm_start_multithreaded() and 53 /// llvm_stop_multithreaded(). 54 void remove_fatal_error_handler(); 55 56 /// ScopedFatalErrorHandler - This is a simple helper class which just 57 /// calls install_fatal_error_handler in its constructor and 58 /// remove_fatal_error_handler in its destructor. 59 struct ScopedFatalErrorHandler { 60 explicit ScopedFatalErrorHandler(fatal_error_handler_t handler, 61 void *user_data = 0) { 62 install_fatal_error_handler(handler, user_data); 63 } 64 65 ~ScopedFatalErrorHandler() { remove_fatal_error_handler(); } 66 }; 67 68 /// Reports a serious error, calling any installed error handler. These 69 /// functions are intended to be used for error conditions which are outside 70 /// the control of the compiler (I/O errors, invalid user input, etc.) 71 /// 72 /// If no error handler is installed the default is to print the message to 73 /// standard error, followed by a newline. 74 /// After the error handler is called this function will call exit(1), it 75 /// does not return. 76 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const char *reason); 77 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const std::string &reason); 78 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(StringRef reason); 79 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const Twine &reason); 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 llvm_unreachable_internal(const char *msg=0, 85 const char *file=0, 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
