Introduce new error handling API.

This will replace exit()/abort() style error handling with an API
that allows clients to register custom error handling hooks.
The default is to call exit(1) when no error handler is provided.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74922 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/ErrorHandling.h

@@ -0,0 +1,52 @@
+//===- llvm/Support/ErrorHandling.h - Callbacks for errors ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines an API used to indicate error conditions.
+// Callbacks can be registered for these errors through this API.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_ERRORHANDLING_H
+#define LLVM_SUPPORT_ERRORHANDLING_H
+
+#include "llvm/Support/Compiler.h"
+
+namespace llvm {
+  // An error handler callback.
+  typedef void (*llvm_error_handler_t)(const std::string& reason);
+
+  // Installs a new error handler: this function will be called whenever a
+  // serious 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);
+
+  // Restores default error handling behaviour.
+  // This must not be called between llvm_start_multithreaded() and
+  // llvm_stop_multithreaded().
+  void llvm_remove_error_handler(void);
+
+  // Reports a serious error, calling any installed error handler.
+  // If no error handler is installed the default is to print the message to
+  void llvm_report_error(const std::string &reason) NORETURN;
+
+  // This function calls abort().
+  // Call this after assert(0), so that compiler knows the path is not
+  // reachable.
+  void llvm_unreachable(void) NORETURN;
+}
+
+#endif
+