Stop assuming CFSTR is a constant-time expression with Clang 15
#4872
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From Clang 15, nested static initializer inside statement-expression is no longer a constant-time expression (See https://reviews.llvm.org/D127201). OSS Foundation defines `CFSTR` as a macro rather than `__builtin___CFStringMakeConstantString` and it uses nested static initializer inside statement-expression, so we can't assume `CFSTR` itself is always a constant-time expression. This patch removes some `static` qualifiers associated with `CFSTR` to make them acceptable with Clang 15 and later.
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@swift-ci Please test |
kateinoigakukun
requested review from
parkera,
drewmaxwell-apple and
MaxDesiatov
and removed request for
drewmaxwell-apple
|
The original issue seems fixed, but XCTest is still failing due to another issue (will be fixed by #4873) https://ci.swift.org/job/swift-corelibs-foundation-PR-macOS/364/console |
parkera
approved these changes
Feb 15, 2024
|
Thanks! |
parkera
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Feb 15, 2024
…iftlang#4872) From Clang 15, nested static initializer inside statement-expression is no longer a constant-time expression (See https://reviews.llvm.org/D127201). OSS Foundation defines `CFSTR` as a macro rather than `__builtin___CFStringMakeConstantString` and it uses nested static initializer inside statement-expression, so we can't assume `CFSTR` itself is always a constant-time expression. This patch removes some `static` qualifiers associated with `CFSTR` to make them acceptable with Clang 15 and later.
etcwilde
pushed a commit
to etcwilde/swift-corelibs-foundation
that referenced
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May 11, 2024
…iftlang#4872) From Clang 15, nested static initializer inside statement-expression is no longer a constant-time expression (See https://reviews.llvm.org/D127201). OSS Foundation defines `CFSTR` as a macro rather than `__builtin___CFStringMakeConstantString` and it uses nested static initializer inside statement-expression, so we can't assume `CFSTR` itself is always a constant-time expression. This patch removes some `static` qualifiers associated with `CFSTR` to make them acceptable with Clang 15 and later.
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From Clang 15, nested static initializer inside statement-expression is no longer a constant-time expression (See https://reviews.llvm.org/D127201). OSS Foundation defines
CFSTRas a macro rather than__builtin___CFStringMakeConstantStringand it uses nested static initializer inside statement-expression, so we can't assumeCFSTRitself is always a constant-time expression.This patch removes some
staticqualifiers associated withCFSTRto make them acceptable with Clang 15 and later.I confirmed there is no change at LLVM IR level between before/after this patch with Clang 14 and
-O3, so I assume Clang 15 and later also can optimize those non-static variables to be static global rodata. So this fix does not cause any performance regression.This issue was originally found in #4866 (comment)