Bug 112145 – LLINT C loop warning fix for GCC

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

[Csaba Osztrogonác]

C loop backend isn't buildable for JSVALUE32_64 platforms now:
https://bugs.webkit.org/show_bug.cgi?id=112141

After the fix proposed in this bug the build fails with false positive warnings:
generated/LLIntAssembly.h: In static member function 'static JSC::JSValue JSC::LLInt::CLoop::execute(JSC::CallFrame*, JSC::OpcodeID, bool)':
generated/LLIntAssembly.h:3444:80: error: 't0.JSC::CLoopRegister::<anonymous>.JSC::CLoopRegister::<anonymous union>::instruction' may be used uninitialized in this function [-Werror=uninitialized]
/home/oszi/WebKit/Source/JavaScriptCore/llint/LowLevelInterpreter.cpp:305:19: note: 't0.JSC::CLoopRegister::<anonymous>.JSC::CLoopRegister::<anonymous union>::instruction' was declared here
generated/LLIntAssembly.h:3279:80: error: 't1.JSC::CLoopRegister::<anonymous>.JSC::CLoopRegister::<anonymous union>::i' may be used uninitialized in this function [-Werror=uninitialized]
/home/oszi/WebKit/Source/JavaScriptCore/llint/LowLevelInterpreter.cpp:305:23: note: 't1.JSC::CLoopRegister::<anonymous>.JSC::CLoopRegister::<anonymous union>::i' was declared here
cc1plus: all warnings being treated as errors

We should shut this warning down for GCC similar to MSVC. :) Patch is coming soon.

[Csaba Osztrogonác]

Created attachment 192726 [details]
Patch

[Filip Pizlo]

Comment on attachment 192726 [details]
Patch

r=me

[Filip Pizlo]

Actually, I think there may be a better way.  I think that the initializations to zero are necessary on all smart compilers.  We should make them unconditional.

[Filip Pizlo]

Comment on attachment 192726 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=192726&action=review

My review still stands since this is a build fix and you probably want to land it quickly.  Your call if you want to try my improved version in this patch or in another one.

> Source/JavaScriptCore/llint/LowLevelInterpreter.cpp:300
> -#if COMPILER(MSVC)
> +#if COMPILER(MSVC) || COMPILER(GCC)

Maybe just remove this, and then #endif?

[Csaba Osztrogonác]

Created attachment 192887 [details]
updated patch for EWS

[Csaba Osztrogonác]

(In reply to comment #5)
> Created an attachment (id=192887) [details]
> updated patch for EWS

It wasn't so important to land the original patch, let's see if
we can make all compiler happy with unconditional initialization.

[WebKit Review Bot]

Comment on attachment 192887 [details]
updated patch for EWS

Clearing flags on attachment: 192887

Committed r145703: <http://trac.webkit.org/changeset/145703>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.