From 62fac040c83bea33d43bbc98d6f11189b058d097 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Martin=20Storsj=C3=B6?= Date: Wed, 2 Aug 2023 00:30:29 +0300 Subject: [PATCH] intreadwrite: Indicate potential aliasing in AV_RN/AV_WN for Clang/MSVC mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use the GCC specific codepath for Clang in MSVC mode too. This matches the condition used in a number of other places. MSVC doesn't have a way to signal potential aliasing, while GCC (and Clang) can use __attribute__((may_alias)) for this purpose. When building with Clang in MSVC mode, __GNUC__ isn't defined but _MSC_VER is as Clang primarily impersonates MSVC - but even then it does support the GCC style attributes. The GCC specific codepath uses av_alias, which expands to the may_alias attribute if supported. The MSVC specific codepath doesn't use av_alias so far (as MSVC doesn't support any corresponding attribute). This fixes a couple HEVC decoder tests when built with Clang 14 or newer in MSVC mode (with issues observed on all of x86_64, armv7 and aarch64). Signed-off-by: Martin Storsjö --- libavutil/intreadwrite.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavutil/intreadwrite.h b/libavutil/intreadwrite.h index c4679fdba4..21df7887f3 100644 --- a/libavutil/intreadwrite.h +++ b/libavutil/intreadwrite.h @@ -213,7 +213,7 @@ typedef union { * by per-arch headers. */ -#if defined(__GNUC__) +#if defined(__GNUC__) || defined(__clang__) union unaligned_64 { uint64_t l; } __attribute__((packed)) av_alias; union unaligned_32 { uint32_t l; } __attribute__((packed)) av_alias;