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

lib/Support/ErrorHandling.cpp

@@ -0,0 +1,53 @@
+//===- lib/Support/ErrorHandling.cpp - 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 for error handling, it supersedes cerr+abort(), and 
+// cerr+exit() style error handling.
+// Callbacks can be registered for these errors through this API.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/System/Threading.h"
+#include <cassert>
+#include <cstdlib>
+
+using namespace llvm;
+using namespace std;
+
+static llvm_error_handler_t ErrorHandler = 0;
+namespace llvm {
+void llvm_install_error_handler(llvm_error_handler_t handler) {
+  assert(!llvm_is_multithreaded() &&
+         "Cannot register error handlers after starting multithreaded mode!\n");
+  assert(!ErrorHandler && "Error handler already registered!\n");
+  ErrorHandler = handler;
+}
+
+void llvm_remove_error_handler(void) {
+  ErrorHandler = 0;
+}
+
+void llvm_report_error(const std::string &reason)
+{
+  if (!ErrorHandler) {
+    errs() << "LLVM ERROR: " << reason << "\n";
+  } else {
+    ErrorHandler(reason);
+  }
+  exit(1);
+}
+
+void llvm_unreachable(void)
+{
+  abort();
+}
+}
+