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author | Aaron Ballman <aaron@aaronballman.com> | 2023-01-18 08:49:45 -0500 |
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committer | Aaron Ballman <aaron@aaronballman.com> | 2023-01-18 08:51:21 -0500 |
commit | e7300e75b51a7e7d4e81975b4be7a6c65f9a8286 (patch) | |
tree | de4e2e3f1ceaca35ae0e37c4417c66b97d9af7d6 /clang/test/SemaCXX/offsetof.cpp | |
parent | 63ba34f3fb752e0a60a78c21ee694e1064a870ab (diff) | |
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Diagnose extensions in 'offsetof'
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm made very
clear that it is an UB having type definitions with in offsetof.
Clang supports defining a type as the first argument as a conforming
extension due to how many projects use the construct in C99 and earlier
to calculate the alignment of a type. GCC also supports defining a type
as the first argument.
This adds extension warnings and documentation for the functionality
Clang explicitly supports.
Fixes #57065
Reverts the revert of 39da55e8f548a11f7dadefa73ea73d809a5f1729
Co-authored-by: Yingchi Long <i@lyc.dev>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
Differential Revision: https://reviews.llvm.org/D133574
Diffstat (limited to 'clang/test/SemaCXX/offsetof.cpp')
-rw-r--r-- | clang/test/SemaCXX/offsetof.cpp | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/clang/test/SemaCXX/offsetof.cpp b/clang/test/SemaCXX/offsetof.cpp index c4b288a..39ea380 100644 --- a/clang/test/SemaCXX/offsetof.cpp +++ b/clang/test/SemaCXX/offsetof.cpp @@ -83,3 +83,18 @@ struct Derived : virtual Base { expected-error {{invalid application of 'offsetof' to a field of a virtual base}} }; } + +int test_definition(void) { + return __builtin_offsetof(struct A // expected-error {{'A' cannot be defined in a type specifier}} + { + int a; + struct B // FIXME: error diagnostic message for nested definitions + // https://reviews.llvm.org/D133574 + // fixme-error{{'A' cannot be defined in '__builtin_offsetof'}} + { + int c; + int d; + }; + B x; + }, a); +} |