[FMV] Require all function versions declared in TU with default defin… #328
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labrinea
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Jul 4, 2024
It was raised in llvm#81494 that we are not generating correct code when there is no TU-local caller. The suggestion was to emit a resolver: * Whenever there is a use in the TU. * When the TU has a definition of the default version. See the comment for more details: llvm#81494 (comment) This got addressed with llvm#84405. Generating a resolver on use means that we may end up with multiple resolvers across different translation units. Those resolvers may not be the same because each translation unit may contain different version declarations (user's fault). Therefore the order of linking the final image determines which of these weak symbols gets selected, resulting in non consisted behavior. I am proposing to stop emitting a resolver on use and only do so in the translation unit which contains the default defition. This way we guarantee the existance of a single resolver. Now, when a versioned function is used we want to emit a declaration of the function symbol omitting the multiversion mangling. I have added a requirement to ACLE mandating that all the function versions are declared in the translation unit which contains the default definition: ARM-software/acle#328
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Thanks! |
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LGTM too. |
labrinea
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Jul 18, 2024
It was raised in #81494 that we are not generating correct code when there is no TU-local caller. The suggestion was to emit a resolver: * Whenever there is a use in the TU. * When the TU has a definition of the default version. See the comment for more details: #81494 (comment) This got addressed with #84405. Generating a resolver on use means that we may end up with multiple resolvers across different translation units. Those resolvers may not be the same because each translation unit may contain different version declarations (user's fault). Therefore the order of linking the final image determines which of these weak symbols gets selected, resulting in non consisted behavior. I am proposing to stop emitting a resolver on use and only do so in the translation unit which contains the default definition. This way we guarantee the existence of a single resolver. Now, when a versioned function is used we want to emit a declaration of the function symbol omitting the multiversion mangling. I have added a requirement to ACLE mandating that all the function versions are declared in the translation unit which contains the default definition: ARM-software/acle#328
Harini0924
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Jul 22, 2024
It was raised in llvm#81494 that we are not generating correct code when there is no TU-local caller. The suggestion was to emit a resolver: * Whenever there is a use in the TU. * When the TU has a definition of the default version. See the comment for more details: llvm#81494 (comment) This got addressed with llvm#84405. Generating a resolver on use means that we may end up with multiple resolvers across different translation units. Those resolvers may not be the same because each translation unit may contain different version declarations (user's fault). Therefore the order of linking the final image determines which of these weak symbols gets selected, resulting in non consisted behavior. I am proposing to stop emitting a resolver on use and only do so in the translation unit which contains the default definition. This way we guarantee the existence of a single resolver. Now, when a versioned function is used we want to emit a declaration of the function symbol omitting the multiversion mangling. I have added a requirement to ACLE mandating that all the function versions are declared in the translation unit which contains the default definition: ARM-software/acle#328
sgundapa
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Jul 23, 2024
It was raised in llvm#81494 that we are not generating correct code when there is no TU-local caller. The suggestion was to emit a resolver: * Whenever there is a use in the TU. * When the TU has a definition of the default version. See the comment for more details: llvm#81494 (comment) This got addressed with llvm#84405. Generating a resolver on use means that we may end up with multiple resolvers across different translation units. Those resolvers may not be the same because each translation unit may contain different version declarations (user's fault). Therefore the order of linking the final image determines which of these weak symbols gets selected, resulting in non consisted behavior. I am proposing to stop emitting a resolver on use and only do so in the translation unit which contains the default definition. This way we guarantee the existence of a single resolver. Now, when a versioned function is used we want to emit a declaration of the function symbol omitting the multiversion mangling. I have added a requirement to ACLE mandating that all the function versions are declared in the translation unit which contains the default definition: ARM-software/acle#328
yuxuanchen1997
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Jul 25, 2024
Summary: It was raised in #81494 that we are not generating correct code when there is no TU-local caller. The suggestion was to emit a resolver: * Whenever there is a use in the TU. * When the TU has a definition of the default version. See the comment for more details: #81494 (comment) This got addressed with #84405. Generating a resolver on use means that we may end up with multiple resolvers across different translation units. Those resolvers may not be the same because each translation unit may contain different version declarations (user's fault). Therefore the order of linking the final image determines which of these weak symbols gets selected, resulting in non consisted behavior. I am proposing to stop emitting a resolver on use and only do so in the translation unit which contains the default definition. This way we guarantee the existence of a single resolver. Now, when a versioned function is used we want to emit a declaration of the function symbol omitting the multiversion mangling. I have added a requirement to ACLE mandating that all the function versions are declared in the translation unit which contains the default definition: ARM-software/acle#328 Test Plan: Reviewers: Subscribers: Tasks: Tags: Differential Revision: https://phabricator.intern.facebook.com/D60250878
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…ition.
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