Changeset 214289 in webkit for trunk/Source/JavaScriptCore/interpreter/Interpreter.cpp

Timestamp:

Mar 22, 2017, 6:14:06 PM (8 years ago)

Author:

[email protected]

Message:

Add support for Error.stackTraceLimit.
​https://bugs.webkit.org/show_bug.cgi?id=169904

Reviewed by Saam Barati.

JSTests:

• stress/error-stack-trace-limit.js: Added.

Source/JavaScriptCore:

Since there's no standard for this yet, we'll implement Error.stackTraceLimit
based on how Chrome does it. This includes some idiosyncrasies like:

1. If we set Error.stackTraceLimit = 0, then new Error().stack yields an empty stack trace (Chrome has a title with no stack frame entries).
2. If we set Error.stackTraceLimit = {] (i.e. to a non-number value), then new Error().stack is undefined.

Chrome and IE defaults their Error.stackTraceLimit to 10. We'll default ours to
100 because 10 may be a bit too skimpy and it is not that costly to allow up to
100 frames instead of 10.

The default value for Error.stackTraceLimit is specified by
Options::defaultErrorStackTraceLimit().

Also, the Exception object now limits the number of stack trace frames it captures
to the limit specified by Options::exceptionStackTraceLimit().

Note: the Exception object captures a stack trace that is not necessarily the
same as the one in an Error object being thrown:

• The Error object captures the stack trace at the point of object creation.

• The Exception object captures the stack trace at the point that the exception is thrown. This stack trace is captured even when throwing a value that is not an Error object e.g. a primitive value. The Exception object stack trace is only used by WebInspector to identify where a value is thrown from. Hence, it does not necessary make sense the Exception object stack trace limited by Error.stackTraceLimit. Instead, we have it use own Options::exceptionStackTraceLimit().

• interpreter/Interpreter.cpp:

(JSC::Interpreter::unwind):

• jsc.cpp:

(dumpException):

• runtime/CommonIdentifiers.h:
• runtime/Error.cpp:

(JSC::addErrorInfoAndGetBytecodeOffset):

• runtime/ErrorConstructor.cpp:

(JSC::ErrorConstructor::finishCreation):
(JSC::ErrorConstructor::put):
(JSC::ErrorConstructor::deleteProperty):

• runtime/ErrorConstructor.h:

(JSC::ErrorConstructor::stackTraceLimit):

• runtime/Exception.cpp:

(JSC::Exception::finishCreation):

• runtime/Options.h:

LayoutTests:

Rebased test.

• js/Object-getOwnPropertyNames-expected.txt:
• js/script-tests/Object-getOwnPropertyNames.js:

File:

• trunk/Source/JavaScriptCore/interpreter/Interpreter.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/interpreter/Interpreter.cpp

@@ -683 +683 @@
         exceptionValue = jsNull();
 
-    ASSERT_UNUSED(scope, scope.exception() && scope.exception()->stack().size());
+    ASSERT_UNUSED(scope, scope.exception() && (!Options::exceptionStackTraceLimit() || scope.exception()->stack().size()));
 
     // Calculate an exception handler vPC, unwinding call frames as necessary.