Add an ExceptionBarrier around outbound calls to patched methods in IE. In so...

chrome_frame/exception_barrier.cc

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// A class to make it easy to tag exception propagation boundaries and
+// get crash reports of exceptions that pass over same.
+#include "chrome_frame/exception_barrier.h"
+
+enum {
+  // Flag set by exception handling machinery when unwinding
+  EH_UNWINDING = 0x00000002
+};
+
+ExceptionBarrier::ExceptionHandler ExceptionBarrier::s_handler_ = NULL;
+
+// This function must be extern "C" to match up with the SAFESEH
+// declaration in our corresponding ASM file
+extern "C" EXCEPTION_DISPOSITION __cdecl
+ExceptionBarrierHandler(struct _EXCEPTION_RECORD *exception_record,
+                        void * establisher_frame,
+                        struct _CONTEXT *context,
+                        void * reserved) {
+  establisher_frame;  // unreferenced formal parameter
+  reserved;
+  if (!(exception_record->ExceptionFlags & EH_UNWINDING)) {
+    // When the exception is really propagating through us, we'd like to be
+    // called before the state of the program has been modified by the stack
+    // unwinding. In the absence of an exception handler, the unhandled
+    // exception filter gets called between the first chance and the second
+    // chance exceptions, so Windows pops either the JIT debugger or WER UI.
+    // This is not desirable in most of the cases.
+    ExceptionBarrier::ExceptionHandler handler = ExceptionBarrier::handler();
+    if (handler) {
+      EXCEPTION_POINTERS ptrs = { exception_record, context };
+
+      handler(&ptrs);
+    }
+  }
+
+  return ExceptionContinueSearch;
+}