diff mbox series

[FFmpeg-devel] configure: Explicitly check for static_assert

Message ID DU0P250MB074747A7EF71A16009ACCF488F322@DU0P250MB0747.EURP250.PROD.OUTLOOK.COM
State Superseded
Headers show
Series [FFmpeg-devel] configure: Explicitly check for static_assert | expand


Context Check Description
yinshiyou/make_loongarch64 success Make finished
yinshiyou/make_fate_loongarch64 success Make fate finished
andriy/make_x86 success Make finished
andriy/make_fate_x86 success Make fate finished

Commit Message

Andreas Rheinhardt March 21, 2024, 3:41 p.m. UTC
C11 provides static assertions via _Static_assert and
provides static_assert as a convenience define for this
in assert.h. MSVC 19.27 declares support C11, but does
not support _Static_assert, but somehow supports
static_assert. That's therefore what we use.

But apparently there are some old GCC toolchains where
_Static_assert is supported, but assert.h does not provide
the fallback define. Some fate boxes are affected by this

This commit therefore checks whether static_assert works
with assert.h included; if not, it checks whether using
-Dstatic_assert=_Static_assert fixes it. Otherwise it errors

[1]: https://fate.ffmpeg.org/report.cgi?time=20240321123620&slot=sh4-debian-qemu-gcc-4.7

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
 configure | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
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diff --git a/configure b/configure
index 6d7b33b0ff..61075608ea 100755
--- a/configure
+++ b/configure
@@ -5589,6 +5589,21 @@  check_cxxflags_cc -std=$stdcxx ctype.h "__cplusplus >= 201103L" ||
 check_cflags_cc -std=$stdc ctype.h "__STDC_VERSION__ >= 201112L" ||
     { check_cflags_cc -std=c11 ctype.h "__STDC_VERSION__ >= 201112L" && stdc="c11" || die "Compiler lacks C11 support"; }
+for static_assert in "" _Static_assert; do
+    test_cc ${static_assert:+-Dstatic_assert=$static_assert} <<EOF && { test -z "$static_assert" || add_cppflags "-Dstatic_assert=$static_assert"; } && break
+#include <assert.h>
+#include <stddef.h>
+struct Foo {
+    int a;
+    void *ptr;
+} obj;
+static_assert(offsetof(struct Foo, a) == 0,
+              "First element of struct does not have offset 0");
+static_assert(offsetof(struct Foo, ptr) >= offsetof(struct Foo, a) + sizeof(obj.a),
+              "elements not properly ordered in struct");
+done || die "Compiler lacks support for C11 static_assert"
 check_cppflags -D_FILE_OFFSET_BITS=64
 check_cppflags -D_LARGEFILE_SOURCE