Bug 183435 - [JSC] Optimize inherits<T> if T is final type
Summary: [JSC] Optimize inherits<T> if T is final type
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: JavaScriptCore (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Yusuke Suzuki
URL:
Keywords: InRadar
Depends on: 183429
Blocks:
  Show dependency tree / graph
 
Reported: 2018-03-08 01:32 PST by Yusuke Suzuki
Modified: 2018-03-08 10:25 PST (History)
7 users (show)

See Also:

Attachments
Patch (131.62 KB, patch)
2018-03-08 08:19 PST, Yusuke Suzuki 		no flags Details | Formatted Diff | Diff
Patch (130.93 KB, patch)
2018-03-08 09:22 PST, Yusuke Suzuki 		mark.lam: review+
Details | Formatted Diff | Diff
Show Obsolete (1) View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Yusuke Suzuki 2018-03-08 01:32:56 PST 
If T is a final type, we do not need to traverse hierarchy.

Consider a final type T,

jsDynamicCast<T*>(vm, cell);

in this case,

if (cell->classInfo(vm) == T::info())
    return static_cast<T*>(cell);
return nullptr;

is enough. We can this optimization in JSCast.h with std::is_final<T>.
Comment 1 Yusuke Suzuki 2018-03-08 08:19:34 PST 
Created attachment 335299 [details]
Patch
Comment 2 Yusuke Suzuki 2018-03-08 09:22:47 PST 
Created attachment 335304 [details]
Patch
Comment 3 Mark Lam 2018-03-08 10:04:56 PST 
Comment on attachment 335304 [details]
Patch

r=me
Comment 4 Yusuke Suzuki 2018-03-08 10:22:48 PST 
Thanks!
Comment 5 Yusuke Suzuki 2018-03-08 10:24:14 PST 
Committed r229413: <https://trac.webkit.org/changeset/229413>
Comment 6 Radar WebKit Bug Importer 2018-03-08 10:25:26 PST 
<rdar://problem/38267844>