Bug 95103 – GCC warning in JSActivation is causing Mac EWS errors

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Jon Lee]

None of the patches going through Mac EWS are succeeding because of a warning that GCC is treating as an error:

CompileC /Volumes/Data/WebKit/WebKitBuild/JavaScriptCore.build/Release/JavaScriptCore.build/Objects-normal/x86_64/JSActivation.o runtime/JSActivation.cpp normal x86_64 c++ com.apple.compilers.gcc.4_2
    cd /Volumes/Data/WebKit/Source/JavaScriptCore
    setenv LANG en_US.US-ASCII
    /Developer/usr/bin/gcc-4.2 -x c++ -arch x86_64 -fmessage-length=0 -pipe -Wno-trigraphs -fno-exceptions -fno-rtti -fpascal-strings -O3 -Werror -Wmissing-prototypes -Wnon-virtual-dtor -Wsign-compare -Wnewline-eof -DNDEBUG -DHAVE_DTRACE=1 -DWEBKIT_VERSION_MIN_REQUIRED=WEBKIT_VERSION_LATEST -DHAVE_HEADER_DETECTION_H -fasm-blocks -fstrict-aliasing -mmacosx-version-min=10.7 -gdwarf-2 -fvisibility=hidden -fvisibility-inlines-hidden -fno-threadsafe-statics -I/Volumes/Data/WebKit/WebKitBuild/JavaScriptCore.build/Release/JavaScriptCore.build/JavaScriptCore.hmap -I/Volumes/Data/WebKit/WebKitBuild/Release/include -I/Volumes/Data/WebKit/WebKitBuild/Release/DerivedSources/JavaScriptCore -I. -Iicu -I/Volumes/Data/WebKit/WebKitBuild/Release/usr/local/include -I/Volumes/Data/WebKit/WebKitBuild/JavaScriptCore.build/Release/JavaScriptCore.build/DerivedSources/x86_64 -I/Volumes/Data/WebKit/WebKitBuild/JavaScriptCore.build/Release/JavaScriptCore.build/DerivedSources -Wall -Wextra -Wcast-qual -Wchar-subscripts -Wextra-tokens -Wformat=2 -Winit-self -Wmissing-format-attribute -Wmissing-noreturn -Wpacked -Wpointer-arith -Wredundant-decls -Wundef -Wwrite-strings -F/Volumes/Data/WebKit/WebKitBuild/Release -include /Volumes/Data/WebKit/WebKitBuild/PrecompiledHeaders/JavaScriptCorePrefix-gvhpdgusmukbdobchmcjrzzcdyvs/JavaScriptCorePrefix.h -c /Volumes/Data/WebKit/Source/JavaScriptCore/runtime/JSActivation.cpp -o /Volumes/Data/WebKit/WebKitBuild/JavaScriptCore.build/Release/JavaScriptCore.build/Objects-normal/x86_64/JSActivation.o
cc1plus: warnings being treated as errors
/Volumes/Data/WebKit/Source/JavaScriptCore/runtime/JSActivation.cpp: In static member function 'static void JSC::JSActivation::visitChildren(JSC::JSCell*, JSC::SlotVisitor&)':
/Volumes/Data/WebKit/Source/JavaScriptCore/runtime/JSActivation.cpp:74: warning: dereferencing type-punned pointer will break strict-aliasing rules

Mark speculated blame goes to Geoff, so starting there.

[Radar WebKit Bug Importer]

<rdar://problem/12180632>

[Geoffrey Garen]

Committed r126906: <http://trac.webkit.org/changeset/126906>