[Mesa-dev] [PATCH 08/15] glsl: Switch ast_type_qualifier to a 128-bit bitset.

[Roland Scheidegger]

Please don't wait any longer. We really want appveyor (and some of our
own build systems) going again...

Roland

Am 27.02.2018 um 19:58 schrieb Francisco Jerez:
> Thanks for testing.  I'm going to land the build fix with your
> Tested-by's if nobody raises any concerns in the next 24h.
> 
> "Kyriazis, George" <george.kyriazis at intel.com> writes:
> 
>> It also fixes the errors that I was getting with gcc 5.4.0 with configure build on ubuntu 16.04.
>>
>> Tested-By: George Kyriazis <george.kyriazis at intel.com<mailto:george.kyriazis at intel.com>>
>>
>> On Feb 25, 2018, at 6:52 PM, Roland Scheidegger <sroland at vmware.com<mailto:sroland at vmware.com>> wrote:
>>
>> Am 25.02.2018 um 21:12 schrieb Francisco Jerez:
>> Roland Scheidegger <sroland at vmware.com<mailto:sroland at vmware.com>> writes:
>>
>> Am 25.02.2018 um 03:35 schrieb Francisco Jerez:
>> Roland Scheidegger <sroland at vmware.com<mailto:sroland at vmware.com>> writes:
>>
>> This seems to have broken compilation with some gcc versions (with scons
>> build):
>>
>> In file included from src/compiler/glsl/ast_array_index.cpp:24:0:
>> src/compiler/glsl/ast.h:648:16: error: member
>> ‘ast_type_qualifier::bitset_t ast_type_qualifier::flags::i’ with
>> constructor not allowed in union
>>       bitset_t i;
>>                ^
>>
>> Oops...  And the only reason bitset_t has a default constructor was...
>> to avoid using another C++11 feature (defaulted member functions).
>> Does the attached patch fix the build failure for you?  The cleaner
>> alternative would be to define the default constructor of the bitset
>> object like 'T() = default', but that would imply dropping support for
>> GCC 4.2-4.3 which don't implement the feature...
>>
>> FWIW the compile error was happening with gcc 4.8 - I didn't see it with
>> gcc 5.4.
>> (I don't think at vmware we'd care about anything older than gcc 4.4 at
>> least but last time someone wanted to bump gcc requirements there were
>> still people requiring gcc 4.2.)
>>
>> The patch compiles albeit there's about two dozen warnings like the
>> following:
>> glsl/ast_type.cpp: In member function 'bool
>> ast_fully_specified_type::has_qualifiers(_mesa_glsl_parse_state*) const':
>> glsl/ast_type.cpp:50:67: warning: ISO C++ says that these are ambiguous,
>> even though the worst conversion for the first is better than the worst
>> conversion for the second: [enabled by default]
>>    return (this->qualifier.flags.i & ~subroutine_only.flags.i) != 0;
>>                                                                   ^
>> In file included from glsl/ast.h:31:0,
>>                 from glsl/ast_type.cpp:24:
>> ../../src/util/bitset.h:181:7: note: candidate 1: bool operator!=(const
>> ast_type_qualifier::bitset_t&, unsigned int)
>>       operator!=(const T &b, BITSET_WORD x)                     \
>>       ^
>> glsl/ast.h:477:4: note: in expansion of macro 'DECLARE_BITSET_T'
>>    DECLARE_BITSET_T(bitset_t, 128);
>>    ^
>> glsl/ast_type.cpp:50:67: note: candidate 2: operator!=(int, int) <built-in>
>>    return (this->qualifier.flags.i & ~subroutine_only.flags.i) != 0;
>>                                                                   ^
>> Roland
>>
>>
>> Ah, yeah, that's because I didn't provide overloads for signed integer
>> types, but it should be harmless since the two candidates have the same
>> semantics, and should go away with a C++11-capable compiler.  I think
>> the attached patch should shut the warnings on older compilers.
>>
>> Yes, that compiles without warnings (with gcc 4.8)
>> Tested-by: Roland Scheidegger <sroland at vmware.com<mailto:sroland at vmware.com>>
>>
>>
>>
>>
>>
>>
>> src/compiler/glsl/ast.h:648:16: note: unrestricted unions only available
>> with -std=c++11 or -std=gnu++11
>> scons: *** [build/linux-x86_64-checked/compiler/glsl/ast_array_index.os]
>> Error 1
>> src/gallium/tests/unit/u_format_test.c: In function ‘main’:
>> src/gallium/tests/unit/u_format_test.c:649:44: warning: array subscript
>> is above array bounds [-Warray-bounds]
>>          unpacked[i][j] = test->unpacked[i][j][1];
>>                                            ^
>> In file included from src/compiler/glsl/ast_expr.cpp:24:0:
>> src/compiler/glsl/ast.h:648:16: error: member
>> ‘ast_type_qualifier::bitset_t ast_type_qualifier::flags::i’ with
>> constructor not allowed in union
>>       bitset_t i;
>>                ^
>> src/compiler/glsl/ast.h:648:16: note: unrestricted unions only available
>> with -std=c++11 or -std=gnu++11
>>
>> Roland
>>
>> [...]
>>
>>
>>
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