mirror of
https://github.com/llvm/llvm-project.git
synced 2025-04-25 00:16:05 +00:00
6abe19ac58
This patch makes Clang predefine `_CRT_USE_BUILTIN_OFFSETOF` in MS-compatible modes. The macro can make the `offsetof` provided by MS UCRT's `<stddef.h>` to select the `__builtin_offsetof` version, so with it Clang (Clang-cl) can directly consume UCRT's `offsetof`. MSVC predefines the macro as `1` since at least VS 2017 19.14, but I think it's also OK to define it in "older" compatible modes. Fixes #59689.
29 lines
851 B
C
29 lines
851 B
C
// RUN: %clang_cc1 %s -triple i686-pc-win32 -fsyntax-only -verify -fms-compatibility
|
|
// RUN: %clang_cc1 %s -triple i686-pc-win32 -fsyntax-only -verify
|
|
// expected-no-diagnostics
|
|
|
|
typedef __typeof__(sizeof(0)) size_t;
|
|
|
|
#ifdef _MSC_VER
|
|
#ifndef _CRT_USE_BUILTIN_OFFSETOF
|
|
#error _CRT_USE_BUILTIN_OFFSETOF should be predefined in MSVC-compatible modes.
|
|
#endif
|
|
#else
|
|
#ifdef _CRT_USE_BUILTIN_OFFSETOF
|
|
#error _CRT_USE_BUILTIN_OFFSETOF should not be predefined in non-MSVC-compatible modes.
|
|
#endif
|
|
#endif
|
|
|
|
#if defined _MSC_VER && !defined _CRT_USE_BUILTIN_OFFSETOF
|
|
#ifdef __cplusplus
|
|
#define offsetof(s,m) ((::size_t)&reinterpret_cast<char const volatile&>((((s*)0)->m)))
|
|
#else
|
|
#define offsetof(s,m) ((size_t)&(((s*)0)->m))
|
|
#endif
|
|
#else
|
|
#define offsetof(s,m) __builtin_offsetof(s,m)
|
|
#endif
|
|
|
|
struct S { int a; };
|
|
_Static_assert(offsetof(struct S, a) == 0, "");
|