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[5.7][stdlib] Fix nullability logic of memcmp #42359

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Merged
merged 2 commits into from
May 10, 2022
Merged

[5.7][stdlib] Fix nullability logic of memcmp #42359

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9155ea1
Fix type of `memcmp` on Windows
stevapple Mar 13, 2022
6899bbb
Improve `memcmp` extern logic
stevapple Apr 6, 2022
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7 changes: 4 additions & 3 deletions stdlib/public/SwiftShims/LibcShims.h
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Original file line number Diff line number Diff line change
Expand Up @@ -60,10 +60,11 @@ static inline __swift_size_t _swift_stdlib_strlen_unsigned(const unsigned char *
SWIFT_READONLY
static inline int _swift_stdlib_memcmp(const void *s1, const void *s2,
__swift_size_t n) {
#if defined(__APPLE__) || defined(__ANDROID__) || defined(__OpenBSD__)
extern int memcmp(const void * _Nullable, const void * _Nullable, __swift_size_t);
// FIXME: Is there a way to identify Glibc specifically?
#if defined(__gnu_linux__)
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I used __GLIBC__ before, doesn't that work?

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@stevapple stevapple Apr 15, 2022 •
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No, because the shim doesn’t (and cannot, I suppose) include any header from Glibc, so any Glibc-defined macros seem not available.

extern int memcmp(const void * _Nonnull, const void * _Nonnull, __swift_size_t);
#else
extern int memcmp(const void *, const void *, __swift_size_t);
extern int memcmp(const void * _Null_unspecified, const void * _Null_unspecified, __swift_size_t);
#endif
return memcmp(s1, s2, n);
}
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