LLVM  14.0.0git
ErrorHandling.h
Go to the documentation of this file.
1 //===- llvm/Support/ErrorHandling.h - Fatal error handling ------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines an API used to indicate fatal error conditions. Non-fatal
10 // errors (most of them) should be handled through LLVMContext.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_SUPPORT_ERRORHANDLING_H
15 #define LLVM_SUPPORT_ERRORHANDLING_H
16 
17 #include "llvm/Support/Compiler.h"
18 
19 namespace llvm {
20  class StringRef;
21  class Twine;
22 
23  /// An error handler callback.
24  typedef void (*fatal_error_handler_t)(void *user_data,
25  const char *reason,
26  bool gen_crash_diag);
27 
28  /// install_fatal_error_handler - Installs a new error handler to be used
29  /// whenever a serious (non-recoverable) error is encountered by LLVM.
30  ///
31  /// If no error handler is installed the default is to print the error message
32  /// to stderr, and call exit(1). If an error handler is installed then it is
33  /// the handler's responsibility to log the message, it will no longer be
34  /// printed to stderr. If the error handler returns, then exit(1) will be
35  /// called.
36  ///
37  /// It is dangerous to naively use an error handler which throws an exception.
38  /// Even though some applications desire to gracefully recover from arbitrary
39  /// faults, blindly throwing exceptions through unfamiliar code isn't a way to
40  /// achieve this.
41  ///
42  /// \param user_data - An argument which will be passed to the install error
43  /// handler.
45  void *user_data = nullptr);
46 
47  /// Restores default error handling behaviour.
49 
50  /// ScopedFatalErrorHandler - This is a simple helper class which just
51  /// calls install_fatal_error_handler in its constructor and
52  /// remove_fatal_error_handler in its destructor.
55  void *user_data = nullptr) {
56  install_fatal_error_handler(handler, user_data);
57  }
58 
60  };
61 
62 /// Reports a serious error, calling any installed error handler. These
63 /// functions are intended to be used for error conditions which are outside
64 /// the control of the compiler (I/O errors, invalid user input, etc.)
65 ///
66 /// If no error handler is installed the default is to print the message to
67 /// standard error, followed by a newline.
68 /// After the error handler is called this function will call abort(), it
69 /// does not return.
70 /// NOTE: The std::string variant was removed to avoid a <string> dependency.
71 [[noreturn]] void report_fatal_error(const char *reason,
72  bool gen_crash_diag = true);
73 [[noreturn]] void report_fatal_error(StringRef reason,
74  bool gen_crash_diag = true);
75 [[noreturn]] void report_fatal_error(const Twine &reason,
76  bool gen_crash_diag = true);
77 
78 /// Installs a new bad alloc error handler that should be used whenever a
79 /// bad alloc error, e.g. failing malloc/calloc, is encountered by LLVM.
80 ///
81 /// The user can install a bad alloc handler, in order to define the behavior
82 /// in case of failing allocations, e.g. throwing an exception. Note that this
83 /// handler must not trigger any additional allocations itself.
84 ///
85 /// If no error handler is installed the default is to print the error message
86 /// to stderr, and call exit(1). If an error handler is installed then it is
87 /// the handler's responsibility to log the message, it will no longer be
88 /// printed to stderr. If the error handler returns, then exit(1) will be
89 /// called.
90 ///
91 ///
92 /// \param user_data - An argument which will be passed to the installed error
93 /// handler.
95  void *user_data = nullptr);
96 
97 /// Restores default bad alloc error handling behavior.
99 
101 
102 /// Reports a bad alloc error, calling any user defined bad alloc
103 /// error handler. In contrast to the generic 'report_fatal_error'
104 /// functions, this function might not terminate, e.g. the user
105 /// defined error handler throws an exception, but it won't return.
106 ///
107 /// Note: When throwing an exception in the bad alloc handler, make sure that
108 /// the following unwind succeeds, e.g. do not trigger additional allocations
109 /// in the unwind chain.
110 ///
111 /// If no error handler is installed (default), throws a bad_alloc exception
112 /// if LLVM is compiled with exception support. Otherwise prints the error
113 /// to standard error and calls abort().
114 [[noreturn]] void report_bad_alloc_error(const char *Reason,
115  bool GenCrashDiag = true);
116 
117 /// This function calls abort(), and prints the optional message to stderr.
118 /// Use the llvm_unreachable macro (that adds location info), instead of
119 /// calling this function directly.
120 [[noreturn]] void
121 llvm_unreachable_internal(const char *msg = nullptr, const char *file = nullptr,
122  unsigned line = 0);
123 }
124 
125 /// Marks that the current location is not supposed to be reachable.
126 /// In !NDEBUG builds, prints the message and location info to stderr.
127 /// In NDEBUG builds, becomes an optimizer hint that the current location
128 /// is not supposed to be reachable. On compilers that don't support
129 /// such hints, prints a reduced message instead and aborts the program.
130 ///
131 /// Use this instead of assert(0). It conveys intent more clearly and
132 /// allows compilers to omit some unnecessary code.
133 #ifndef NDEBUG
134 #define llvm_unreachable(msg) \
135  ::llvm::llvm_unreachable_internal(msg, __FILE__, __LINE__)
136 #elif defined(LLVM_BUILTIN_UNREACHABLE)
137 #define llvm_unreachable(msg) LLVM_BUILTIN_UNREACHABLE
138 #else
139 #define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal()
140 #endif
141 
142 #endif
llvm::remove_bad_alloc_error_handler
void remove_bad_alloc_error_handler()
Restores default bad alloc error handling behavior.
Definition: ErrorHandling.cpp:135
llvm
This file implements support for optimizing divisions by a constant.
Definition: AllocatorList.h:23
llvm::install_bad_alloc_error_handler
void install_bad_alloc_error_handler(fatal_error_handler_t handler, void *user_data=nullptr)
Installs a new bad alloc error handler that should be used whenever a bad alloc error,...
Definition: ErrorHandling.cpp:125
llvm::install_out_of_memory_new_handler
void install_out_of_memory_new_handler()
Definition: ErrorHandling.cpp:190
llvm::llvm_unreachable_internal
void llvm_unreachable_internal(const char *msg=nullptr, const char *file=nullptr, unsigned line=0)
This function calls abort(), and prints the optional message to stderr.
Definition: ErrorHandling.cpp:198
llvm::remove_fatal_error_handler
void remove_fatal_error_handler()
Restores default error handling behaviour.
Definition: ErrorHandling.cpp:74
llvm::ScopedFatalErrorHandler
ScopedFatalErrorHandler - This is a simple helper class which just calls install_fatal_error_handler ...
Definition: ErrorHandling.h:53
llvm::install_fatal_error_handler
void install_fatal_error_handler(fatal_error_handler_t handler, void *user_data=nullptr)
install_fatal_error_handler - Installs a new error handler to be used whenever a serious (non-recover...
Definition: ErrorHandling.cpp:64
llvm::report_fatal_error
void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:140
llvm::report_bad_alloc_error
void report_bad_alloc_error(const char *Reason, bool GenCrashDiag=true)
Reports a bad alloc error, calling any user defined bad alloc error handler.
Definition: ErrorHandling.cpp:143
llvm::ScopedFatalErrorHandler::~ScopedFatalErrorHandler
~ScopedFatalErrorHandler()
Definition: ErrorHandling.h:59
file
dot regions Print regions of function to dot file(with no function bodies)"
llvm::ScopedFatalErrorHandler::ScopedFatalErrorHandler
ScopedFatalErrorHandler(fatal_error_handler_t handler, void *user_data=nullptr)
Definition: ErrorHandling.h:54
Compiler.h
llvm::fatal_error_handler_t
void(* fatal_error_handler_t)(void *user_data, const char *reason, bool gen_crash_diag)
An error handler callback.
Definition: ErrorHandling.h:24