Bug 147023

Summary: RegExp::match() should set m_state to ByteCode if compilation fails.
Product: WebKit Reporter: Mark Lam <mark.lam>
Component: JavaScriptCoreAssignee: Mark Lam <mark.lam>
Status: RESOLVED FIXED    
Severity: Normal CC: benjamin, fpizlo, ggaren, keith_miller, mmirman, msaboff, saam, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
the fix. msaboff: review+

Description Mark Lam 2015-07-16 16:02:00 PDT 
A RegExp has a YarrCodeBlock that has 4 MacroAssemblerCodeRefs for compiled code.  If one of these compilations succeeds, RegExp::m_state will be set to JITCode.  Subsequently, if RegExp tries to compile another one of these but fails, m_state will be left untouched i.e. it still says JITCode.  As a result, when RegExp::match() later tries to execute the non-existant compiled code, it will crash.  The fix is to downgrade m_state to ByteCode if RegExp ever fails to compile.

This failure should be rare.  We'll do the minimal work here to fix the issue and keep an eye on the perf bots.  If perf regresses, we can do some optimization work then.
Comment 1 Mark Lam 2015-07-16 16:03:23 PDT 
<rdar://problem/21764196>
Comment 2 Mark Lam 2015-07-16 16:13:28 PDT 
Created attachment 256937 [details]
the fix.
Comment 3 Michael Saboff 2015-07-16 16:24:26 PDT 
Comment on attachment 256937 [details]
the fix.

r=me
Comment 4 Mark Lam 2015-07-16 19:30:32 PDT 
I've run the jsc and layout tests and did not see any regressions.

Landed in r186920: <http://trac.webkit.org/r186920>.