X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FErrorHandling.h;h=ca5dec0173c513936885caa24bebbdffc3ea8d9f;hb=d5e1be03eda2e8036f136fdf12a5f5d9e1e684d8;hp=fae7d8094b0eec5fb2689ad9c3a84e2d8c2b34e8;hpb=b6017b03dab80e1e7bfeec4e7debff0fefa9563e;p=oota-llvm.git

diff --git a/include/llvm/Support/ErrorHandling.h b/include/llvm/Support/ErrorHandling.h
index fae7d8094b0..ca5dec0173c 100644
--- a/include/llvm/Support/ErrorHandling.h
+++ b/include/llvm/Support/ErrorHandling.h
@@ -1,4 +1,4 @@
-//===- llvm/Support/ErrorHandling.h - Callbacks for errors ------*- C++ -*-===//
+//===- llvm/Support/ErrorHandling.h - Fatal error handling ------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,47 +7,100 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file defines an API used to indicate error conditions.
-// Callbacks can be registered for these errors through this API.
+// This file defines an API used to indicate fatal error conditions.  Non-fatal
+// errors (most of them) should be handled through LLVMContext.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_SUPPORT_ERRORHANDLING_H
 #define LLVM_SUPPORT_ERRORHANDLING_H
 
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
 #include <string>
 
 namespace llvm {
+  class Twine;
+
   /// An error handler callback.
-  typedef void (*llvm_error_handler_t)(const std::string& reason);
+  typedef void (*fatal_error_handler_t)(void *user_data,
+                                        const std::string& reason);
 
-  /// Installs a new error handler: this function will be called whenever a
-  /// serious error is encountered by LLVM.
+  /// install_fatal_error_handler - Installs a new error handler to be used
+  /// whenever a serious (non-recoverable) error is encountered by LLVM.
+  ///
   /// If you are using llvm_start_multithreaded, you should register the handler
   /// before doing that.
   ///
   /// If no error handler is installed the default is to print the error message
-  /// to stderr, and call exit(1).
-  /// If an error handler is installed then it is the handler's responsibility
-  /// to log the message, it will no longer be printed to stderr.
-  /// If the error handler returns, then exit(1) will be called.
-  void llvm_install_error_handler(llvm_error_handler_t handler);
+  /// to stderr, and call exit(1).  If an error handler is installed then it is
+  /// the handler's responsibility to log the message, it will no longer be
+  /// printed to stderr.  If the error handler returns, then exit(1) will be
+  /// called.
+  ///
+  /// It is dangerous to naively use an error handler which throws an exception.
+  /// Even though some applications desire to gracefully recover from arbitrary
+  /// faults, blindly throwing exceptions through unfamiliar code isn't a way to
+  /// achieve this.
+  ///
+  /// \param user_data - An argument which will be passed to the install error
+  /// handler.
+  void install_fatal_error_handler(fatal_error_handler_t handler,
+                                   void *user_data = 0);
 
   /// Restores default error handling behaviour.
   /// This must not be called between llvm_start_multithreaded() and
   /// llvm_stop_multithreaded().
-  void llvm_remove_error_handler(void);
+  void remove_fatal_error_handler();
 
-  /// Reports a serious error, calling any installed error handler.
+  /// ScopedFatalErrorHandler - This is a simple helper class which just
+  /// calls install_fatal_error_handler in its constructor and
+  /// remove_fatal_error_handler in its destructor.
+  struct ScopedFatalErrorHandler {
+    explicit ScopedFatalErrorHandler(fatal_error_handler_t handler,
+                                     void *user_data = 0) {
+      install_fatal_error_handler(handler, user_data);
+    }
+
+    ~ScopedFatalErrorHandler() { remove_fatal_error_handler(); }
+  };
+
+  /// Reports a serious error, calling any installed error handler. These
+  /// functions are intended to be used for error conditions which are outside
+  /// the control of the compiler (I/O errors, invalid user input, etc.)
+  ///
   /// If no error handler is installed the default is to print the message to
-  void llvm_report_error(const std::string &reason) NORETURN;
+  /// standard error, followed by a newline.
+  /// After the error handler is called this function will call exit(1), it 
+  /// does not return.
+  LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const char *reason);
+  LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const std::string &reason);
+  LLVM_ATTRIBUTE_NORETURN void report_fatal_error(StringRef reason);
+  LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const Twine &reason);
 
-  /// This function calls abort().
-  /// Call this after assert(0), so that compiler knows the path is not
-  /// reachable.
-  void llvm_unreachable(void) NORETURN;
+  /// This function calls abort(), and prints the optional message to stderr.
+  /// Use the llvm_unreachable macro (that adds location info), instead of
+  /// calling this function directly.
+  LLVM_ATTRIBUTE_NORETURN void llvm_unreachable_internal(const char *msg=0,
+                                                         const char *file=0,
+                                                         unsigned line=0);
 }
 
+/// Marks that the current location is not supposed to be reachable.
+/// In !NDEBUG builds, prints the message and location info to stderr.
+/// In NDEBUG builds, becomes an optimizer hint that the current location
+/// is not supposed to be reachable.  On compilers that don't support
+/// such hints, prints a reduced message instead.
+///
+/// Use this instead of assert(0).  It conveys intent more clearly and
+/// allows compilers to omit some unnecessary code.
+#ifndef NDEBUG
+#define llvm_unreachable(msg) \
+  ::llvm::llvm_unreachable_internal(msg, __FILE__, __LINE__)
+#elif defined(LLVM_BUILTIN_UNREACHABLE)
+#define llvm_unreachable(msg) LLVM_BUILTIN_UNREACHABLE
+#else
+#define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal()
 #endif
 
+#endif