Bug 40214 – Clean up error construction / throwing in JSC.

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Gavin Barraclough]

The one egregious insanity here is that creating an error requires a VM-entry-esqe-host call (the string argument is wrapped as a JS object & pushed on the RegisterFile, then unwrapped back to a UString).  Changing this also means you only require a global object, not an ExecState, to create an error.

The methods to create error objects are also parameterized requiring a switch on the type, which can be made cleaner and faster by moving to a separate method per error type.  Code to add divot information to error had been duplicated, and is coalesced back into a single function.

Convenience methods added to create & throw type & syntax error with a default error message, since this is a common case.

Also, errors are currently thrown either using "throwError(exec, error)" or "exec->setException(error)" - unify on the former, since this is more commonly used.  Add "throwVMError(exec, error)" equivalents, as a convenience for cases where the result was being wrapped in "JSValue::encode(...)".

[Gavin Barraclough]

Created attachment 57983 [details]
The patch

[WebKit Review Bot]

Attachment 57983 [details] did not pass style-queue:

Failed to run "['WebKitTools/Scripts/check-webkit-style', '--no-squash']" exit_code: 1
JavaScriptCore/runtime/Error.h:28:  Alphabetical sorting problem.  [build/include_order] [4]
Total errors found: 1 in 87 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Sam Weinig]

Comment on attachment 57983 [details]
The patch

Looks good other than changing the type variable in op_new_error. r=me

[WebKit Review Bot]

Attachment 57983 [details] did not build on win:
Build output: http://webkit-commit-queue.appspot.com/results/3085180

[Gavin Barraclough]

http://trac.webkit.org/changeset/60762