When GCC >=4.7 (or another compiler supporting C++11) is used, then UChar type from ICU 50 is a typedef to char16_t instead of unsigned short int. This results in compilation failure in WebKit. To reproduce this bug, you must: 1. Build ICU 50 using GCC >=4.7. ICU will automatically be built with -std=c++11 flag. 2. Build WebKit with -std=c++11 (or -std=gnu++11) manually added to CXXFLAGS. Compilation failure does not occur with ICU 49 or older. Last lines from `make`: CXX Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSBase.lo CXX Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSCallbackConstructor.lo CXX Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSCallbackFunction.lo CXX Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSCallbackObject.lo CXX Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSClassRef.lo CXX Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSContextRef.lo CXX Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSObjectRef.lo CXX Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSStringRef.lo Source/JavaScriptCore/API/JSStringRef.cpp: In function ‘OpaqueJSString* JSStringCreateWithCharacters(const JSChar*, size_t)’: Source/JavaScriptCore/API/JSStringRef.cpp:39:50: error: invalid conversion from ‘const JSChar* {aka const short unsigned int*}’ to ‘const UChar* {aka const char16_t*}’ [-fpermissive] In file included from Source/JavaScriptCore/API/JSStringRef.cpp:30:0: Source/JavaScriptCore/API/OpaqueJSString.h:44:39: error: initializing argument 1 of ‘static WTF::PassRefPtr<OpaqueJSString> OpaqueJSString::create(const UChar*, unsigned int)’ [-fpermissive] Source/JavaScriptCore/API/JSStringRef.cpp: In function ‘const JSChar* JSStringGetCharactersPtr(JSStringRef)’: Source/JavaScriptCore/API/JSStringRef.cpp:75:31: error: invalid conversion from ‘UChar* {aka char16_t*}’ to ‘const JSChar* {aka const short unsigned int*}’ [-fpermissive] make[1]: *** [Source/JavaScriptCore/API/libjavascriptcoregtk_3_0_la-JSStringRef.lo] Error 1
Could you please post a snippet of how exactly ICU 5.0 defines UChar?
(In reply to comment #1) > Could you please post a snippet of how exactly ICU 5.0 defines UChar? See http://gcc.gnu.org/ml/gcc-help/2012-11/msg00018.html
(In reply to comment #1) > ICU 5.0 Versioning of ICU has changed since 49: http://userguide.icu-project.org/design#TOC-ICU-Release-Version-Number-ICU-49-and-later- (In reply to comment #2) > See http://gcc.gnu.org/ml/gcc-help/2012-11/msg00018.html (Undefined references mentioned in that thread will occur when building WebKit with older version of C++11 if ICU has been built with C++11.)
(In reply to comment #3) > older version of C++11 s/older version of C++11/older version of C++/
Maybe caused by http://bugs.icu-project.org/trac/ticket/9717
(In reply to comment #5) > Maybe caused by http://bugs.icu-project.org/trac/ticket/9717 see there for a possible workaround.
(In reply to comment #5) > Maybe caused by http://bugs.icu-project.org/trac/ticket/9717 This bug in WebKit was caused by solution for ICU ticket 9469. ICU ticket 9717 only suggests temporary workaround (forceful disabling of C++11). The proper solution in WebKit is to add appropriate casts (or use char16_t in more places in WebKit code).
In ICU, I just changed UChar to not automatically become char16_t, but users can add something like CPPFLAGS=-DUCHAR_TYPE=char16_t. See http://bugs.icu-project.org/trac/changeset/32780 If this does not work for WebKit then please reply to http://bugs.icu-project.org/trac/ticket/9728 or on the icu-support mailing list (http://site.icu-project.org/contacts). Best regards, markus
Looks like this is obsolete as per comment #8.