Bug 174463 – Fix compiler warnings when building with GCC 7

• Component: WebKitGTK
• Status: RESOLVED FIXED

[Michael Catanzaro]

[50/5861] Building C object Source/Thi...i/CMakeFiles/brotli.dir/dec/decode.c.o
../../Source/ThirdParty/brotli/dec/decode.c: In function ‘DecodeVarLenUint8’:
../../Source/ThirdParty/brotli/dec/decode.c:143:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
       if (bits == 0) {
          ^
../../Source/ThirdParty/brotli/dec/decode.c:149:5: note: here
     case BROTLI_STATE_DECODE_UINT8_SHORT:
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:160:14: warning: this statement may fall through [-Wimplicit-fallthrough=]
       *value = bits;
       ~~~~~~~^~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:163:5: note: here
     case BROTLI_STATE_DECODE_UINT8_LONG:
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c: In function ‘DecodeMetaBlockLength’:
../../Source/ThirdParty/brotli/dec/decode.c:196:38: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_EMPTY;
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:199:7: note: here
       case BROTLI_STATE_METABLOCK_HEADER_EMPTY:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:207:38: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NIBBLES;
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:210:7: note: here
       case BROTLI_STATE_METABLOCK_HEADER_NIBBLES:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:221:38: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_SIZE;
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:224:7: note: here
       case BROTLI_STATE_METABLOCK_HEADER_SIZE:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:236:38: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->substate_metablock_header =
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
             BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED;
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:240:7: note: here
       case BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:258:38: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_BYTES;
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:261:7: note: here
       case BROTLI_STATE_METABLOCK_HEADER_BYTES:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:270:38: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_METADATA;
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:273:7: note: here
       case BROTLI_STATE_METABLOCK_HEADER_METADATA:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c: In function ‘ReadHuffmanCode’:
../../Source/ThirdParty/brotli/dec/decode.c:694:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
       if (s->sub_loop_counter != 1) {
          ^
../../Source/ThirdParty/brotli/dec/decode.c:706:5: note: here
     case BROTLI_STATE_HUFFMAN_SIMPLE_SIZE:
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:712:27: warning: this statement may fall through [-Wimplicit-fallthrough=]
       s->sub_loop_counter = 0;
       ~~~~~~~~~~~~~~~~~~~~^~~
../../Source/ThirdParty/brotli/dec/decode.c:714:5: note: here
     case BROTLI_STATE_HUFFMAN_SIMPLE_READ: {
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:714:44: warning: this statement may fall through [-Wimplicit-fallthrough=]
     case BROTLI_STATE_HUFFMAN_SIMPLE_READ: {
                                            ^
../../Source/ThirdParty/brotli/dec/decode.c:721:5: note: here
     case BROTLI_STATE_HUFFMAN_SIMPLE_BUILD: {
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:762:27: warning: this statement may fall through [-Wimplicit-fallthrough=]
       s->substate_huffman = BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS;
       ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:765:5: note: here
     case BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS: {
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c: In function ‘DecodeContextMap’:
../../Source/ThirdParty/brotli/dec/decode.c:937:31: warning: this statement may fall through [-Wimplicit-fallthrough=]
       s->substate_context_map = BROTLI_STATE_CONTEXT_MAP_READ_PREFIX;
       ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:939:5: note: here
     case BROTLI_STATE_CONTEXT_MAP_READ_PREFIX: {
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:939:48: warning: this statement may fall through [-Wimplicit-fallthrough=]
     case BROTLI_STATE_CONTEXT_MAP_READ_PREFIX: {
                                                ^
../../Source/ThirdParty/brotli/dec/decode.c:957:5: note: here
     case BROTLI_STATE_CONTEXT_MAP_HUFFMAN:
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:962:31: warning: this statement may fall through [-Wimplicit-fallthrough=]
       s->substate_context_map = BROTLI_STATE_CONTEXT_MAP_DECODE;
       ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:964:5: note: here
     case BROTLI_STATE_CONTEXT_MAP_DECODE: {
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:964:43: warning: this statement may fall through [-Wimplicit-fallthrough=]
     case BROTLI_STATE_CONTEXT_MAP_DECODE: {
                                           ^
../../Source/ThirdParty/brotli/dec/decode.c:1009:5: note: here
     case BROTLI_STATE_CONTEXT_MAP_TRANSFORM: {
     ^~~~
../../Source/ThirdParty/brotli/dec/decode.c: In function ‘CopyUncompressedBlockToOutput’:
../../Source/ThirdParty/brotli/dec/decode.c:1254:34: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_WRITE;
         ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:1257:7: note: here
       case BROTLI_STATE_UNCOMPRESSED_WRITE: {
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c: In function ‘BrotliDecompressStream’:
../../Source/ThirdParty/brotli/dec/decode.c:1952:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_METABLOCK_BEGIN;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:1954:7: note: here
       case BROTLI_STATE_METABLOCK_BEGIN:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:1957:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_METABLOCK_HEADER;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:1959:7: note: here
       case BROTLI_STATE_METABLOCK_HEADER:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:2032:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_HUFFMAN_CODE_1;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:2034:7: note: here
       case BROTLI_STATE_HUFFMAN_CODE_1: {
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:2039:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_HUFFMAN_CODE_2;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:2042:7: note: here
       case BROTLI_STATE_HUFFMAN_CODE_2: {
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:2047:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_HUFFMAN_CODE_3;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:2050:7: note: here
       case BROTLI_STATE_HUFFMAN_CODE_3: {
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:2062:45: warning: this statement may fall through [-Wimplicit-fallthrough=]
       case BROTLI_STATE_METABLOCK_HEADER_2: {
                                             ^
../../Source/ThirdParty/brotli/dec/decode.c:2085:7: note: here
       case BROTLI_STATE_CONTEXT_MODES:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:2090:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_CONTEXT_MAP_1;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:2092:7: note: here
       case BROTLI_STATE_CONTEXT_MAP_1:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:2100:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_CONTEXT_MAP_2;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:2102:7: note: here
       case BROTLI_STATE_CONTEXT_MAP_2:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:2127:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_TREE_GROUP;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:2129:7: note: here
       case BROTLI_STATE_TREE_GROUP:
       ^~~~
../../Source/ThirdParty/brotli/dec/decode.c:2220:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
         s->state = BROTLI_STATE_DONE;
         ~~~~~~~~~^~~~~~~~~~~~~~~~~~~
../../Source/ThirdParty/brotli/dec/decode.c:2222:7: note: here
       case BROTLI_STATE_DONE:
       ^~~~
[466/5861] Building CXX object Source/.../B3LowerMacrosAfterOptimizations.cpp.o
In file included from ../../Source/JavaScriptCore/b3/B3LowerMacrosAfterOptimizations.cpp:36:0:
../../Source/JavaScriptCore/b3/B3ConstPtrValue.h: In instantiation of ‘JSC::B3::ConstPtrValue::ConstPtrValue(JSC::B3::Origin, T*) [with T = float(float) throw ()]’:
../../Source/JavaScriptCore/b3/B3ProcedureInlines.h:38:49:   required from ‘ValueType* JSC::B3::Procedure::add(Arguments ...) [with ValueType = JSC::B3::ConstPtrValue; Arguments = {JSC::B3::Origin, float (*)(float) throw ()}]’
../../Source/JavaScriptCore/b3/B3InsertionSetInlines.h:38:12:   required from ‘ValueType* JSC::B3::InsertionSet::insert(size_t, Arguments ...) [with ValueType = JSC::B3::ConstPtrValue; Arguments = {JSC::B3::Origin, float (*)(float) throw ()}; size_t = long unsigned int]’
../../Source/JavaScriptCore/b3/B3LowerMacrosAfterOptimizations.cpp:99:100:   required from here
../../Source/JavaScriptCore/b3/B3ConstPtrValue.h:56:5: warning: mangled name for ‘JSC::B3::ConstPtrValue::ConstPtrValue(JSC::B3::Origin, T*) [with T = float(float) throw ()]’ will change in C++17 because the exception specification is part of a function type [-Wnoexcept-type]
     ConstPtrValue(Origin origin, T* pointer)
     ^~~~~~~~~~~~~
../../Source/JavaScriptCore/b3/B3ConstPtrValue.h:56:5: warning: mangled name for ‘JSC::B3::ConstPtrValue::ConstPtrValue(JSC::B3::Origin, T*) [with T = float(float) throw ()]’ will change in C++17 because the exception specification is part of a function type [-Wnoexcept-type]
In file included from ../../Source/WTF/wtf/FastMalloc.h:26:0,
                 from ../../Source/JavaScriptCore/config.h:31,
                 from ../../Source/JavaScriptCore/b3/B3LowerMacrosAfterOptimizations.cpp:26:
../../Source/WTF/wtf/StdLibExtras.h:143:15: warning: mangled name for ‘ToType WTF::bitwise_cast(FromType) [with ToType = long int; FromType = float (*)(float) throw ()]’ will change in C++17 because the exception specification is part of a function type [-Wnoexcept-type]
 inline ToType bitwise_cast(FromType from)
               ^~~~~~~~~~~~
In file included from ../../Source/JavaScriptCore/b3/B3LowerMacrosAfterOptimizations.cpp:36:0:
../../Source/JavaScriptCore/b3/B3ConstPtrValue.h:56:5: warning: mangled name for ‘JSC::B3::ConstPtrValue::ConstPtrValue(JSC::B3::Origin, T*) [with T = float(float) throw ()]’ will change in C++17 because the exception specification is part of a function type [-Wnoexcept-type]
     ConstPtrValue(Origin origin, T* pointer)
     ^~~~~~~~~~~~~
In file included from ../../Source/JavaScriptCore/b3/B3BasicBlockInlines.h:31:0,
                 from ../../Source/JavaScriptCore/b3/B3LowerMacrosAfterOptimizations.cpp:31:
../../Source/JavaScriptCore/b3/B3ProcedureInlines.h:36:12: warning: mangled name for ‘ValueType* JSC::B3::Procedure::add(Arguments ...) [with ValueType = JSC::B3::ConstPtrValue; Arguments = {JSC::B3::Origin, float (*)(float) throw ()}]’ will change in C++17 because the exception specification is part of a function type [-Wnoexcept-type]
 ValueType* Procedure::add(Arguments... arguments)
            ^~~~~~~~~
In file included from ../../Source/JavaScriptCore/b3/B3LowerMacrosAfterOptimizations.cpp:37:0:
../../Source/JavaScriptCore/b3/B3InsertionSetInlines.h:36:12: warning: mangled name for ‘ValueType* JSC::B3::InsertionSet::insert(size_t, Arguments ...) [with ValueType = JSC::B3::ConstPtrValue; Arguments = {JSC::B3::Origin, float (*)(float) throw ()}]’ will change in C++17 because the exception specification is part of a function type [-Wnoexcept-type]
 ValueType* InsertionSet::insert(size_t index, Arguments... arguments)
            ^~~~~~~~~~~~
[522/5861] Building CXX object Source/...ptCore.dir/bytecode/CallLinkInfo.cpp.o
In file included from ../../Source/WTF/wtf/StdLibExtras.h:33:0,
                 from ../../Source/WTF/wtf/FastMalloc.h:26,
                 from ../../Source/JavaScriptCore/config.h:31,
                 from ../../Source/JavaScriptCore/bytecode/CallLinkInfo.cpp:26:
../../Source/JavaScriptCore/bytecode/CallLinkInfo.cpp: In static member function ‘static JSC::CallLinkInfo::CallType JSC::CallLinkInfo::callTypeFor(JSC::OpcodeID)’:
../../Source/JavaScriptCore/bytecode/CallLinkInfo.cpp:54:48: warning: enum constant in boolean context [-Wint-in-bool-context]
     ASSERT(opcodeID == op_tail_call_varargs || op_tail_call_forward_arguments);
                                                ^
../../Source/WTF/wtf/Assertions.h:296:11: note: in definition of macro ‘ASSERT’
     if (!(assertion)) { \
           ^~~~~~~~~
[735/5861] Building C object Source/Ja.../disassembler/udis86/udis86_decode.c.o
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c: In function ‘decode_operand’:
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c:751:18: warning: this statement may fall through [-Wimplicit-fallthrough=]
       u->br_far  = 1;
       ~~~~~~~~~~~^~~
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c:753:5: note: here
     case OP_M:
     ^~~~
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c:754:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
       if (MODRM_MOD(modrm(u)) == 3) {
          ^
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c:758:5: note: here
     case OP_E:
     ^~~~
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c:773:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
       if (MODRM_MOD(modrm(u)) != 3) {
          ^
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c:777:5: note: here
     case OP_Q:
     ^~~~
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c:784:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
       if (MODRM_MOD(modrm(u)) != 3) {
          ^
../../Source/JavaScriptCore/disassembler/udis86/udis86_decode.c:788:5: note: here
     case OP_W:
     ^~~~
[978/5861] Building CXX object Source/...criptCore.dir/runtime/ConfigFile.cpp.o
../../Source/JavaScriptCore/runtime/ConfigFile.cpp: In lambda function:
../../Source/JavaScriptCore/runtime/ConfigFile.cpp:281:62: warning: ‘snprintf’ output may be truncated before the last format character [-Wformat-truncation=]
     auto parseLogFile = [&](StatementNesting statementNesting) {
                                                              ^
../../Source/JavaScriptCore/runtime/ConfigFile.cpp:286:29: note: ‘snprintf’ output 2 or more bytes (assuming 4098) into a destination of size 4097
                     snprintf(logPathname, s_maxPathLength + 1, "%s/%s", m_configDirectory, filename);
                     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[2701/5861] Building CXX object Source.../css/CSSComputedStyleDeclaration.cpp.o
../../Source/WebCore/css/CSSComputedStyleDeclaration.cpp: In member function ‘WTF::RefPtr<WebCore::CSSValue> WebCore::ComputedStyleExtractor::propertyValue(WebCore::CSSPropertyID, WebCore::EUpdateLayout)’:
../../Source/WebCore/css/CSSComputedStyleDeclaration.cpp:3344:13: warning: this statement may fall through [-Wimplicit-fallthrough=]
             }
             ^
../../Source/WebCore/css/CSSComputedStyleDeclaration.cpp:3345:9: note: here
         case CSSPropertyTextIndent: {
         ^~~~
[3172/5861] Building CXX object Source...s/WebCore.dir/html/ImageDocument.cpp.o
../../Source/WebCore/html/ImageDocument.cpp: In member function ‘void WebCore::ImageDocument::createDocumentStructure()’:
../../Source/WebCore/html/ImageDocument.cpp:226:103: warning: enum constant in boolean context [-Wint-in-bool-context]
         body->setInlineStyleProperty(CSSPropertyBackgroundColor, "white", CSSPrimitiveValue::CSS_IDENT);
                                                                                                       ^
[4595/5861] Building CXX object Source...ort.dir/testing/InternalSettings.cpp.o
../../Source/WebCore/testing/InternalSettings.cpp: In member function ‘WebCore::ExceptionOr<void> WebCore::InternalSettings::setShouldManageAudioSessionCategory(bool)’:
../../Source/WebCore/testing/InternalSettings.cpp:839:78: warning: unused parameter ‘should’ [-Wunused-parameter]
 ExceptionOr<void> InternalSettings::setShouldManageAudioSessionCategory(bool should)
                                                                              ^~~~~~
[5146/5861] Building CXX object Source...Platform/IPC/unix/ConnectionUnix.cpp.o
../../Source/WebKit2/Platform/IPC/unix/ConnectionUnix.cpp: In member function ‘bool IPC::Connection::sendOutputMessage(IPC::UnixMessage&)’:
../../Source/WebKit2/Platform/IPC/unix/ConnectionUnix.cpp:454:42: warning: this statement may fall through [-Wimplicit-fallthrough=]
                 attachmentInfo[i].setSize(attachments[i].size());
                 ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
../../Source/WebKit2/Platform/IPC/unix/ConnectionUnix.cpp:456:13: note: here
             case Attachment::SocketType:
             ^~~~

[Carlos Alberto Lopez Perez]

This would fail to build on the Mac port as they pass both -Werror,-Wimplicit-fallthrough

[Michael Catanzaro]

(In reply to Carlos Alberto Lopez Perez from comment #1)
> This would fail to build on the Mac port as they pass both
> -Werror,-Wimplicit-fallthrough

I don't understand your comment. We need to build brotli with -Wno-implicit-fallthrough. Mac port does not build brotli at all.

[Michael Catanzaro]

Ah, I see we do have some -Wimplicit-fallthrough warnings elsewhere. But clearly Mac port is not failing to build, so either their compiler somehow implements the warning differently, or maybe they don't use it for all files.

[Michael Catanzaro]

Created attachment 315364 [details]
Patch

[Michael Catanzaro]

Created attachment 315366 [details]
Patch

[Darin Adler]

Comment on attachment 315366 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=315366&action=review

This patch probably should not have [GTK] on it, since it’s not in platform-specific code even if it’s for the benefit of ports that can use gcc.

> Source/cmake/OptionsCommon.cmake:78
> +        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-noexcept-type")

Is this working around a bug, or what?

[Michael Catanzaro]

(In reply to Darin Adler from comment #6)
> Comment on attachment 315366 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=315366&action=review
> 
> This patch probably should not have [GTK] on it, since it’s not in
> platform-specific code even if it’s for the benefit of ports that can use
> gcc.

Good point.

> > Source/cmake/OptionsCommon.cmake:78
> > +        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-noexcept-type")
> 
> Is this working around a bug, or what?

No, it's just a bad warning. Apparently noexcept is part of the function signature in C++17, so the mangled names of a bunch of functions will change between C++14 and C++17. That's a major ABI change. But these are not public API functions, so it doesn't matter. The only place that -Wnoexcept-type *might* be a useful warning is in the public C++ API headers, but those are slated for removal anyway.

On the other hand, I see now that those functions use throw() rather than noexcept. I should probably modernize that in a follow-up patch.

[Michael Catanzaro]

(In reply to Michael Catanzaro from comment #7)
> > > Source/cmake/OptionsCommon.cmake:78
> > > +        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-noexcept-type")
> > 
> > Is this working around a bug, or what?
> 
> No, it's just a bad warning.

Er, actually those functions do not have noexcept specifiers at all. You're right, it is a GCC bug:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80985

I'll add a comment about that to the patch.

[Michael Catanzaro]

(In reply to Michael Catanzaro from comment #8)
> Er, actually those functions do not have noexcept specifiers at all. You're
> right, it is a GCC bug:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80985

Well, I guess the warning is working as designed, it's just assuming that we compile some of our C++ files with C++14 and some with C++17. Then the code would break. Fortunately, we don't do that.

[Michael Catanzaro]

Committed r219480: <http://trac.webkit.org/changeset/219480>

[Loïc Yhuel]

Comment on attachment 315366 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=315366&action=review

> Source/ThirdParty/brotli/CMakeLists.txt:21
> +    ADD_TARGET_PROPERTIES(brotli COMPILE_FLAGS "-Wno-cast-align -Wno-implicit-fallthrough")

This flag is only supported in gcc >= 7, so with older versions, as soon as there is another warning in the file, it would output :
cc1plus: warning: unrecognized command line option ‘-Wno-implicit-fallthrough’

[Michael Catanzaro]

(In reply to Loïc Yhuel from comment #11)
> This flag is only supported in gcc >= 7, so with older versions, as soon as
> there is another warning in the file, it would output :
> cc1plus: warning: unrecognized command line option
> ‘-Wno-implicit-fallthrough’

Oops, sorry. Will fix.