Avoid object layout changes during GC.

R=mstarzinger@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/11530011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13194 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap.cc

@@ -7223,7 +7223,7 @@ void ErrorObjectList::DeferredFormatStackTrace(Isolate* isolate) {
   // If formatting the stack trace causes a GC, this method will be
   // recursively called.  In that case, skip the recursive call, since
   // the loop modifies the list while iterating over it.
-  if (nested_) return;
+  if (nested_ || isolate->has_pending_exception()) return;
   nested_ = true;
   HandleScope scope(isolate);
   Handle<String> stack_key = isolate->factory()->stack_symbol();
@@ -7249,14 +7249,20 @@ void ErrorObjectList::DeferredFormatStackTrace(Isolate* isolate) {
     JSFunction* getter_fun = JSFunction::cast(getter_obj);
     String* key = isolate->heap()->hidden_stack_trace_symbol();
     if (key != getter_fun->GetHiddenProperty(key)) continue;
+    budget--;
     bool has_exception = false;
     Execution::Call(Handle<Object>(getter_fun, isolate),
                     Handle<Object>(object, isolate),
                     0,
                     NULL,
                     &has_exception);
-    ASSERT(!has_exception);
-    budget--;
+    if (has_exception) {
+      // Hit an exception (most likely a stack overflow).
+      // Wrap up this pass and retry after another GC.
+      isolate->clear_pending_exception();
+      list_[write_index++] = object;
+      budget = 0;
+    }
   }
   list_.Rewind(write_index);
   list_.Trim();

src/messages.js

@@ -1088,9 +1088,9 @@ function captureStackTrace(obj, cons_opt) {
   if (stackTraceLimit < 0 || stackTraceLimit > 10000) {
     stackTraceLimit = 10000;
   }
-  var raw_stack = %CollectStackTrace(obj,
-                                     cons_opt ? cons_opt : captureStackTrace,
-                                     stackTraceLimit);
+  var stack = %CollectStackTrace(obj,
+                                 cons_opt ? cons_opt : captureStackTrace,
+                                 stackTraceLimit);
 
   // Don't be lazy if the error stack formatting is custom (observable).
   if (IS_FUNCTION($Error.prepareStackTrace)) {
@@ -1098,7 +1098,7 @@ function captureStackTrace(obj, cons_opt) {
     // Use default error formatting for the case that custom formatting throws.
     $Error.prepareStackTrace = null;
     var array = [];
-    %MoveArrayContents(GetStackFrames(raw_stack), array);
+    %MoveArrayContents(GetStackFrames(stack), array);
     obj.stack = custom_stacktrace_fun(obj, array);
     $Error.prepareStackTrace = custom_stacktrace_fun;
     return;
@@ -1108,10 +1108,14 @@ function captureStackTrace(obj, cons_opt) {
   // Note that 'obj' and 'this' maybe different when called on objects that
   // have the error object on its prototype chain.  The getter replaces itself
   // with a data property as soon as the stack trace has been formatted.
+  // The getter must not change the object layout as it may be called after GC.
   var getter = function() {
-    var value = FormatStackTrace(error_string, GetStackFrames(raw_stack));
-    %DefineOrRedefineDataProperty(obj, 'stack', value, NONE);
-    return value;
+    if (IS_STRING(stack)) return stack;
+    // Stack is still a raw array awaiting to be formatted.
+    stack = FormatStackTrace(error_string, GetStackFrames(stack));
+    // Release context value.
+    error_string = void 0;
+    return stack;
   };
   %MarkOneShotGetter(getter);
 
@@ -1263,18 +1267,21 @@ function SetUpStackOverflowBoilerplate() {
   // a data property.
   var error_string = boilerplate.name + ": " + boilerplate.message;
 
+  // The getter must not change the object layout as it may be called after GC.
   function getter() {
     var holder = this;
     while (!IS_ERROR(holder)) {
       holder = %GetPrototype(holder);
       if (holder == null) return MakeSyntaxError('illegal_access', []);
     }
-    var raw_stack = %GetOverflowedRawStackTrace(holder);
-    var result = IS_ARRAY(raw_stack)
-                     ? FormatStackTrace(error_string, GetStackFrames(raw_stack))
-                     : void 0;
-    %DefineOrRedefineDataProperty(holder, 'stack', result, NONE);
-    return result;
+    var stack = %GetOverflowedStackTrace(holder);
+    if (IS_STRING(stack)) return stack;
+    if (IS_ARRAY(stack)) {
+      var result = FormatStackTrace(error_string, GetStackFrames(stack));
+      %SetOverflowedStackTrace(holder, result);
+      return result;
+    }
+    return void 0;
   }
   %MarkOneShotGetter(getter);
 
@@ -1282,6 +1289,8 @@ function SetUpStackOverflowBoilerplate() {
   // the receiver is the same as holder, this accessor pair is replaced.
   function setter(v) {
     %DefineOrRedefineDataProperty(this, 'stack', v, NONE);
+    // Release the stack trace that is stored as hidden property, if exists.
+    %SetOverflowedStackTrace(this, void 0);
   }
 
   %DefineOrRedefineAccessorProperty(

src/runtime.cc

@@ -13109,19 +13109,38 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_MarkOneShotGetter) {
 }
 
 
-// Retrieve the raw stack trace collected on stack overflow and delete
-// it since it is used only once to avoid keeping it alive.
-RUNTIME_FUNCTION(MaybeObject*, Runtime_GetOverflowedRawStackTrace) {
+// Retrieve the stack trace.  This could be the raw stack trace collected
+// on stack overflow or the already formatted stack trace string.
+RUNTIME_FUNCTION(MaybeObject*, Runtime_GetOverflowedStackTrace) {
+  HandleScope scope(isolate);
   ASSERT_EQ(args.length(), 1);
   CONVERT_ARG_CHECKED(JSObject, error_object, 0);
   String* key = isolate->heap()->hidden_stack_trace_symbol();
   Object* result = error_object->GetHiddenProperty(key);
-  RUNTIME_ASSERT(result->IsJSArray() || result->IsUndefined());
-  error_object->DeleteHiddenProperty(key);
+  RUNTIME_ASSERT(result->IsJSArray() ||
+                 result->IsString() ||
+                 result->IsUndefined());
   return result;
 }
 
 
+// Set or clear the stack trace attached to an stack overflow error object.
+RUNTIME_FUNCTION(MaybeObject*, Runtime_SetOverflowedStackTrace) {
+  HandleScope scope(isolate);
+  ASSERT_EQ(args.length(), 2);
+  CONVERT_ARG_HANDLE_CHECKED(JSObject, error_object, 0);
+  CONVERT_ARG_HANDLE_CHECKED(HeapObject, value, 1);
+  Handle<String> key = isolate->factory()->hidden_stack_trace_symbol();
+  if (value->IsUndefined()) {
+    error_object->DeleteHiddenProperty(*key);
+  } else {
+    RUNTIME_ASSERT(value->IsString());
+    JSObject::SetHiddenProperty(error_object, key, value);
+  }
+  return *error_object;
+}
+
+
 // Returns V8 version as a string.
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetV8Version) {
   ASSERT_EQ(args.length(), 0);

src/runtime.h

@@ -237,7 +237,8 @@ namespace internal {
   F(GetScript, 1, 1) \
   F(CollectStackTrace, 3, 1) \
   F(MarkOneShotGetter, 1, 1) \
-  F(GetOverflowedRawStackTrace, 1, 1) \
+  F(GetOverflowedStackTrace, 1, 1) \
+  F(SetOverflowedStackTrace, 2, 1) \
   F(GetV8Version, 0, 1) \
   \
   F(ClassOf, 1, 1) \