LLVM  6.0.0svn
ErrorHandling.h
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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 
21 namespace llvm {
22 class 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.
47  void *user_data = nullptr);
48 
49  /// Restores default error handling behaviour.
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.
57  void *user_data = nullptr) {
58  install_fatal_error_handler(handler, user_data);
59  }
60 
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.
72 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const char *reason,
73  bool gen_crash_diag = true);
74 LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const std::string &reason,
75  bool gen_crash_diag = true);
77  bool gen_crash_diag = true);
79  bool gen_crash_diag = true);
80 
81 /// Installs a new bad alloc error handler that should be used whenever a
82 /// bad alloc error, e.g. failing malloc/calloc, is encountered by LLVM.
83 ///
84 /// The user can install a bad alloc handler, in order to define the behavior
85 /// in case of failing allocations, e.g. throwing an exception. Note that this
86 /// handler must not trigger any additional allocations itself.
87 ///
88 /// If no error handler is installed the default is to print the error message
89 /// to stderr, and call exit(1). If an error handler is installed then it is
90 /// the handler's responsibility to log the message, it will no longer be
91 /// printed to stderr. If the error handler returns, then exit(1) will be
92 /// called.
93 ///
94 ///
95 /// \param user_data - An argument which will be passed to the installed error
96 /// handler.
98  void *user_data = nullptr);
99 
100 /// Restores default bad alloc error handling behavior.
102 
103 /// Reports a bad alloc error, calling any user defined bad alloc
104 /// error handler. In contrast to the generic 'report_fatal_error'
105 /// functions, this function is expected to return, e.g. the user
106 /// defined error handler throws an exception.
107 ///
108 /// Note: When throwing an exception in the bad alloc handler, make sure that
109 /// the following unwind succeeds, e.g. do not trigger additional allocations
110 /// in the unwind chain.
111 ///
112 /// If no error handler is installed (default), then a bad_alloc exception
113 /// is thrown if LLVM is compiled with exception support, otherwise an assertion
114 /// is called.
115 void report_bad_alloc_error(const char *Reason, 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.
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.
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_ATTRIBUTE_NORETURN void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:115
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
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, e.g.
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
void remove_fatal_error_handler()
Restores default error handling behaviour.
void(* fatal_error_handler_t)(void *user_data, const std::string &reason, bool gen_crash_diag)
An error handler callback.
Definition: ErrorHandling.h:26
void remove_bad_alloc_error_handler()
Restores default bad alloc error handling behavior.
dot regions Print regions of function to dot file(with no function bodies)"
void report_bad_alloc_error(const char *Reason, bool GenCrashDiag=true)
Reports a bad alloc error, calling any user defined bad alloc error handler.
#define LLVM_ATTRIBUTE_NORETURN
Definition: Compiler.h:206
LLVM_ATTRIBUTE_NORETURN 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.
ScopedFatalErrorHandler - This is a simple helper class which just calls install_fatal_error_handler ...
Definition: ErrorHandling.h:55
ScopedFatalErrorHandler(fatal_error_handler_t handler, void *user_data=nullptr)
Definition: ErrorHandling.h:56
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
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...