EricWF created this revision.
EricWF added reviewers: rsmith, jyknight.
GCC also considers the `__float128` type when constructing `max_align_t`.
Clang's definition is intended to exactly match GCC's, so this patch make Clang
do the same.
NOTE: This breaks the ABI of `max_align_t` by changing its size and alignment
on 32 bit linux platforms.
Repository:
rC Clang
https://reviews.llvm.org/D55057
Files:
lib/Headers/__stddef_max_align_t.h
test/Headers/c11.c
Index: test/Headers/c11.c
===================================================================
--- test/Headers/c11.c
+++ test/Headers/c11.c
@@ -3,6 +3,7 @@
// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -fmodules
-fmodules-cache-path=%t %s -D__STDC_WANT_LIB_EXT1__=1
// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -ffreestanding %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -triple i686-pc-win32
-fms-compatibility-version=17.00 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -triple
i386-unknown-linux-gnu %s
noreturn int f(); // expected-error 1+{{}}
@@ -29,8 +30,17 @@
_Static_assert(sizeof(max_align_t) >= sizeof(long double), "");
_Static_assert(alignof(max_align_t) >= alignof(long double), "");
+
#ifdef _MSC_VER
_Static_assert(sizeof(max_align_t) == sizeof(double), "");
+_Static_assert(alignof(max_align_t) == alignof(double), "");
+#elif defined(__APPLE__)
+_Static_assert(sizeof(max_align_t) == sizeof(long double), "");
+_Static_assert(alignof(max_align_t) == alignof(long double), "");
+#else
+// Test compatibility with GCC's version
+_Static_assert(sizeof(max_align_t) >= sizeof(__float128), "");
+_Static_assert(alignof(max_align_t) >= alignof(__float128), "");
#endif
// If we are freestanding, then also check RSIZE_MAX (in a hosted
implementation
Index: lib/Headers/__stddef_max_align_t.h
===================================================================
--- lib/Headers/__stddef_max_align_t.h
+++ lib/Headers/__stddef_max_align_t.h
@@ -37,6 +37,10 @@
__attribute__((__aligned__(__alignof__(long long))));
long double __clang_max_align_nonce2
__attribute__((__aligned__(__alignof__(long double))));
+#ifdef __i386__
+ __float128 __clang_max_align_nonce3
+ __attribute__((__aligned__(__alignof__(__float128))));
+#endif
} max_align_t;
#endif
Index: test/Headers/c11.c
===================================================================
--- test/Headers/c11.c
+++ test/Headers/c11.c
@@ -3,6 +3,7 @@
// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -fmodules -fmodules-cache-path=%t %s -D__STDC_WANT_LIB_EXT1__=1
// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -ffreestanding %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -triple i686-pc-win32 -fms-compatibility-version=17.00 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -triple i386-unknown-linux-gnu %s
noreturn int f(); // expected-error 1+{{}}
@@ -29,8 +30,17 @@
_Static_assert(sizeof(max_align_t) >= sizeof(long double), "");
_Static_assert(alignof(max_align_t) >= alignof(long double), "");
+
#ifdef _MSC_VER
_Static_assert(sizeof(max_align_t) == sizeof(double), "");
+_Static_assert(alignof(max_align_t) == alignof(double), "");
+#elif defined(__APPLE__)
+_Static_assert(sizeof(max_align_t) == sizeof(long double), "");
+_Static_assert(alignof(max_align_t) == alignof(long double), "");
+#else
+// Test compatibility with GCC's version
+_Static_assert(sizeof(max_align_t) >= sizeof(__float128), "");
+_Static_assert(alignof(max_align_t) >= alignof(__float128), "");
#endif
// If we are freestanding, then also check RSIZE_MAX (in a hosted implementation
Index: lib/Headers/__stddef_max_align_t.h
===================================================================
--- lib/Headers/__stddef_max_align_t.h
+++ lib/Headers/__stddef_max_align_t.h
@@ -37,6 +37,10 @@
__attribute__((__aligned__(__alignof__(long long))));
long double __clang_max_align_nonce2
__attribute__((__aligned__(__alignof__(long double))));
+#ifdef __i386__
+ __float128 __clang_max_align_nonce3
+ __attribute__((__aligned__(__alignof__(__float128))));
+#endif
} max_align_t;
#endif
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