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Differential D107066

[libc++] TEST DO NOT REVIEW
AbandonedPublic

Authored by Mordante on Jul 29 2021, 6:12 AM.

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Summary

Test whether all compilers support concepts.

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Mordante created this revision.Jul 29 2021, 6:12 AM
Herald added a subscriber: arichardson. · View Herald TranscriptJul 29 2021, 6:12 AM
Mordante requested review of this revision.Jul 29 2021, 6:12 AM
Herald added a project: Restricted Project. · View Herald TranscriptJul 29 2021, 6:12 AM
Herald added a reviewer: Restricted Project. · View Herald Transcript
Herald added a subscriber: libcxx-commits. · View Herald Transcript
Mordante mentioned this in D103357: [libc++][format] Add __format_arg_store..Jul 29 2021, 7:00 AM
Harbormaster completed remote builds in B116956: Diff 362746.Jul 29 2021, 7:19 AM
• Quuxplusone added a subscriber: • Quuxplusone.Jul 29 2021, 8:20 AM
• Quuxplusone added inline comments.
libcxx/include/__config
851–856

I think a quicker and dirtier (but more accurate-to-real-life) method of testing this would have been to just unconditionally #undef _LIBCPP_HAS_NO_CONCEPTS and then see what breaks. :)

Mordante added inline comments.Jul 29 2021, 9:46 AM
libcxx/include/__config
851–856

That would also have worked, but I wanted to make sure this path was taken. I didn't want depend on test failures due to not having concepts implemented in the compiler.

ldionne added a subscriber: ldionne.Jul 29 2021, 2:11 PM

AppleClang 12.0 doesn't support concepts. Technically we still support it until 13.0 is out of beta.

In practice, this is going to be a can of worms. Xcode 13 requires macOS 11.0, but we can't do back-deployment testing with macOS 11.0. So if we dropped support for AppleClang 12.0, we would not be able to do back-deployment testing on the hosts that run Xcode 13 anymore. We'll have to figure out a way to do back-deployment testing without being stuck on an older OS. I think that means we'll have to go down the route of remote execution, which is something that we need to do anyway if we ever want to test on funkier platforms like embedded or even just testing on the iOS simulator. It's kind of frustrating that a simple compiler upgrade has such a big chain of dependencies, but I won't let those difficulties dictate which compilers we support.

Mordante abandoned this revision.Jul 30 2021, 12:06 AM

I agree we should be able to update our compilers and be able to support older platforms at the same time.

This patch was mainly to test what the current status of our supported platforms is. I didn't want to change all format patches just to discover concepts aren't properly supported on all platforms yet. With that answer known the patch has served its purpose.

Revision Contents

PathSize
libcxx/
include/
3 lines
utils/
libcxx/
test/
1 line

Diff 362746

libcxx/include/__config

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#endif #endif
#ifndef __cpp_consteval #ifndef __cpp_consteval
# define _LIBCPP_CONSTEVAL _LIBCPP_CONSTEXPR # define _LIBCPP_CONSTEVAL _LIBCPP_CONSTEXPR
#else #else
# define _LIBCPP_CONSTEVAL consteval # define _LIBCPP_CONSTEVAL consteval
#endif #endif
#if !defined(__cpp_concepts) || __cpp_concepts < 201907L #if !defined(__cpp_concepts) || __cpp_concepts < 201907L
#define _LIBCPP_HAS_NO_CONCEPTS #define _LIBCPP_HAS_NO_CONCEPTS
#if _LIBCPP_STD_VER > 17
#error "Platform doesn't support concepts"
#endif
#endif #endif
QuuxplusoneUnsubmitted
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I think a quicker and dirtier (but more accurate-to-real-life) method of testing this would have been to just unconditionally #undef _LIBCPP_HAS_NO_CONCEPTS and then see what breaks. :)

Quuxplusone: I think a quicker and dirtier (but more accurate-to-real-life) method of testing this would…
MordanteAuthorUnsubmitted
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That would also have worked, but I wanted to make sure this path was taken. I didn't want depend on test failures due to not having concepts implemented in the compiler.

Mordante: That would also have worked, but I wanted to make sure this path was taken. I didn't want…
#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_HAS_NO_CONCEPTS) #if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_HAS_NO_CONCEPTS)
#define _LIBCPP_HAS_NO_RANGES #define _LIBCPP_HAS_NO_RANGES
#endif #endif
#ifdef _LIBCPP_CXX03_LANG #ifdef _LIBCPP_CXX03_LANG
# define _LIBCPP_DEFAULT {} # define _LIBCPP_DEFAULT {}
#else #else
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libcxx/utils/libcxx/test/features.py

Show All 32 LinesDEFAULT_FEATURES = [
Feature(name='has-fblocks', when=lambda cfg: hasCompileFlag(cfg, '-fblocks')), Feature(name='has-fblocks', when=lambda cfg: hasCompileFlag(cfg, '-fblocks')),
Feature(name='-fsized-deallocation', when=lambda cfg: hasCompileFlag(cfg, '-fsized-deallocation')), Feature(name='-fsized-deallocation', when=lambda cfg: hasCompileFlag(cfg, '-fsized-deallocation')),
Feature(name='-faligned-allocation', when=lambda cfg: hasCompileFlag(cfg, '-faligned-allocation')), Feature(name='-faligned-allocation', when=lambda cfg: hasCompileFlag(cfg, '-faligned-allocation')),
Feature(name='fdelayed-template-parsing', when=lambda cfg: hasCompileFlag(cfg, '-fdelayed-template-parsing')), Feature(name='fdelayed-template-parsing', when=lambda cfg: hasCompileFlag(cfg, '-fdelayed-template-parsing')),
Feature(name='libcpp-no-if-constexpr', when=lambda cfg: '__cpp_if_constexpr' not in featureTestMacros(cfg)), Feature(name='libcpp-no-if-constexpr', when=lambda cfg: '__cpp_if_constexpr' not in featureTestMacros(cfg)),
Feature(name='libcpp-no-structured-bindings', when=lambda cfg: '__cpp_structured_bindings' not in featureTestMacros(cfg)), Feature(name='libcpp-no-structured-bindings', when=lambda cfg: '__cpp_structured_bindings' not in featureTestMacros(cfg)),
Feature(name='libcpp-no-deduction-guides', when=lambda cfg: featureTestMacros(cfg).get('__cpp_deduction_guides', 0) < 201611), Feature(name='libcpp-no-deduction-guides', when=lambda cfg: featureTestMacros(cfg).get('__cpp_deduction_guides', 0) < 201611),
Feature(name='libcpp-no-concepts', when=lambda cfg: featureTestMacros(cfg).get('__cpp_concepts', 0) < 201907),
Feature(name='has-fobjc-arc', when=lambda cfg: hasCompileFlag(cfg, '-xobjective-c++ -fobjc-arc') and Feature(name='has-fobjc-arc', when=lambda cfg: hasCompileFlag(cfg, '-xobjective-c++ -fobjc-arc') and
sys.platform.lower().strip() == 'darwin'), # TODO: this doesn't handle cross-compiling to Apple platforms. sys.platform.lower().strip() == 'darwin'), # TODO: this doesn't handle cross-compiling to Apple platforms.
Feature(name='objective-c++', when=lambda cfg: hasCompileFlag(cfg, '-xobjective-c++ -fobjc-arc')), Feature(name='objective-c++', when=lambda cfg: hasCompileFlag(cfg, '-xobjective-c++ -fobjc-arc')),
Feature(name='no-noexcept-function-type', when=lambda cfg: featureTestMacros(cfg).get('__cpp_noexcept_function_type', 0) < 201510), Feature(name='no-noexcept-function-type', when=lambda cfg: featureTestMacros(cfg).get('__cpp_noexcept_function_type', 0) < 201510),
Feature(name='non-lockfree-atomics', Feature(name='non-lockfree-atomics',
when=lambda cfg: sourceBuilds(cfg, """ when=lambda cfg: sourceBuilds(cfg, """
#include <atomic> #include <atomic>
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