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

[Francisco Jerez]

Do you care enough to give me a reviewed-by so I could land it right
away?

Roland Scheidegger <sroland at vmware.com> writes:

> 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
>>>
>>> [...]
>>>
>>>
>>>
>>> _______________________________________________
>>> mesa-dev mailing list
>>> mesa-dev at lists.freedesktop.org<mailto:mesa-dev at lists.freedesktop.org>
>>> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
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