abseil's absl::is_trivially_copy_assignable uses deprecated, broken compiler builtin #1201
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royjacobson
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…pe traits Some compiler provided type traits like __has_trivial_constructor have been documented as deprecated for quite some time. Still, some people apparently still use them, even though mixing them with concepts and with deleted functions leads to weird results. There's also disagreement about some edge cases between GCC (which Clang claims to follow) and MSVC. This patch adds deprecation warnings for the usage of those builtins, except for __has_trivial_destructor which doesn't have a GCC alternative. I made the warning on by default, so I had to silence it for some tests but it's not too many. Some (decade old) history of issues with those builtins: #18187 #18559 #22161 #33063 The abseil usage of them that triggered me to add this warning: abseil/abseil-cpp#1201 Weird interaction of those builtins with C++20's conditionally trivial special member functions: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106085 Reviewed By: #clang-language-wg, aaron.ballman Differential Revision: https://reviews.llvm.org/D129170
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On the Mozilla side: https://bugzilla.mozilla.org/show_bug.cgi?id=1779528 (firefox uses libwebrtc which uses abseil-cpp) |
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aaronmondal
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Sep 15, 2022
The old builtins have been depracated in Clang 16. Since they are also present in GCC it should be fine to just use the new variants. Fixes Issue abseil#1201.
mem-frob
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Oct 7, 2022
…pe traits Some compiler provided type traits like __has_trivial_constructor have been documented as deprecated for quite some time. Still, some people apparently still use them, even though mixing them with concepts and with deleted functions leads to weird results. There's also disagreement about some edge cases between GCC (which Clang claims to follow) and MSVC. This patch adds deprecation warnings for the usage of those builtins, except for __has_trivial_destructor which doesn't have a GCC alternative. I made the warning on by default, so I had to silence it for some tests but it's not too many. Some (decade old) history of issues with those builtins: llvm/llvm-project#18187 llvm/llvm-project#18559 llvm/llvm-project#22161 llvm/llvm-project#33063 The abseil usage of them that triggered me to add this warning: abseil/abseil-cpp#1201 Weird interaction of those builtins with C++20's conditionally trivial special member functions: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106085 Reviewed By: #clang-language-wg, aaron.ballman Differential Revision: https://reviews.llvm.org/D129170
copybara-service bot
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Nov 4, 2022
Since upgrading to Clang 15, abseil fails to build, because of abseil/abseil-cpp#1201. PiperOrigin-RevId: 486190797 Change-Id: Ibaa1c03b8d21ae4a83c3825c8d56363aa2f89505
copybara-service bot
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Jan 14, 2023
…p#1201 PiperOrigin-RevId: 501994473
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…p#1201 PiperOrigin-RevId: 501994473
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…p#1201 PiperOrigin-RevId: 502000716
qtprojectorg
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Feb 1, 2023
If you compile with clang 15+, the uses of trivially destructible and assignable are deprecated. This sets this configuration correctly as the ifdef to fix the build. Fixes abseil/abseil-cpp#1201 Related abseil/abseil-cpp#1277 Original Pull Request: abseil/abseil-cpp#1289 Task-number: QTBUG-108240 Change-Id: Id5456e3da01e16e9370f9fa6ed279360e1df523d Reviewed-on: https://codereview.qt-project.org/c/qt/qtwebengine-chromium/+/455716 Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
razmser
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Sep 12, 2023
If you compile with clang 15+, the uses of trivially destructible and assignable are deprecated. This sets this configuration correctly as the ifdef to fix the build. Fixes abseil#1201 Related abseil#1277
razmser
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Sep 12, 2023
If you compile with clang 15+, the uses of trivially destructible and assignable are deprecated. This sets this configuration correctly as the ifdef to fix the build. Fixes abseil#1201 Related abseil#1277
clint-stripe
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Oct 5, 2023
macOS Sonoma brought along a new Xcode version, which broke some things. We need to pick up abseil/abseil-cpp#1201
clintharrison
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Oct 5, 2023
macOS Sonoma brought along a new Xcode version, which broke some things. We need to pick up abseil/abseil-cpp#1201
clintharrison
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Oct 5, 2023
macOS Sonoma brought along a new Xcode version, which broke some things. We need to pick up abseil/abseil-cpp#1201
nelhage
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Oct 7, 2023
* Upgrade abseil for Clang 15 (macOS Sonoma) compatibility macOS Sonoma brought along a new Xcode version, which broke some things. We need to pick up abseil/abseil-cpp#1201 * Move to hedron_compile_commands, add vscode/gopls settings * Update proto to support multiple path/-paths * Support multiple paths in backend * Parse multiple file: ops in the web server * Add C++ version to .bazelrc.ci
wfrisch
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Nov 14, 2023
* Upgrade abseil for Clang 15 (macOS Sonoma) compatibility macOS Sonoma brought along a new Xcode version, which broke some things. We need to pick up abseil/abseil-cpp#1201 * Move to hedron_compile_commands, add vscode/gopls settings * Update proto to support multiple path/-paths * Support multiple paths in backend * Parse multiple file: ops in the web server * Add C++ version to .bazelrc.ci
netkex
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Apr 3, 2024
If you compile with clang 15+, the uses of trivially destructible and assignable are deprecated. This sets this configuration correctly as the ifdef to fix the build. Fixes abseil#1201 Related abseil#1277
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As a side effect of implementing DR2171 for clang, we have discovered that
absl::is_trivially_copy_assignableuses the__has_trivial_assigncompiler builtin.This compiler builtin has bad semantics when deleted functions are involved because clang considers them trivial for this purpose. Specifically it appears that MSVC stl delete the copy assignment operator for
volatile& std::pairwhich causes abseil to assert when instantiatingabsl::Optional<std::pair<int, int>>with MSVC stl.This has been discussed over at https://reviews.llvm.org/D127593. We might revert this change momentarily, but it would be helpful if abseil will stop using the
__has_trivial...builtins.Note that GCC uses the same 'deleted is trivial' semantics as clang, and that those builtins have been deprecated for quite some time: this is a discussion of the same issue from 2017: llvm/llvm-project#33063
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