Define FORCE_ALIGN in config.h

4 files changed, 14 insertions, 16 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ae21a83e..e4d3776d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -470,6 +470,7 @@ if(ALSOFT_REQUIRE_NEON AND NOT HAVE_NEON)
 endif()
 
 
+set(ALSOFT_FORCE_ALIGN )
 set(SSE_FLAGS )
 set(FPMATH_SET "0")
 if(CMAKE_SIZEOF_VOID_P MATCHES "4" AND HAVE_SSE2)
@@ -494,6 +495,7 @@ if(CMAKE_SIZEOF_VOID_P MATCHES "4" AND HAVE_SSE2)
             # OSs don't guarantee this on 32-bit, so externally-callable
             # functions need to ensure an aligned stack.
             set(EXPORT_DECL "${EXPORT_DECL}__attribute__((force_align_arg_pointer))")
+            set(ALSOFT_FORCE_ALIGN "__attribute__((force_align_arg_pointer))")
         endif()
     endif()
 endif()
diff --git a/alc/alc.cpp b/alc/alc.cpp
index 299a1ee9..128b3d7e 100644
--- a/alc/alc.cpp
+++ b/alc/alc.cpp
@@ -3228,11 +3228,17 @@ ALC_API ALCboolean ALC_APIENTRY alcIsRenderFormatSupportedSOFT(ALCdevice *device
  * Renders some samples into a buffer, using the format last set by the
  * attributes given to alcCreateContext.
  */
-FORCE_ALIGN ALC_API void ALC_APIENTRY alcRenderSamplesSOFT(ALCdevice *device, ALCvoid *buffer, ALCsizei samples) noexcept
+#if defined(__GNUC__) && defined(__i386__)
+/* Needed on x86-32 even without SSE codegen, since the mixer may still use SSE
+ * and GCC assumes the stack is aligned (x86-64 ABI guarantees alignment).
+ */
+[[gnu::force_align_arg_pointer]]
+#endif
+ALC_API void ALC_APIENTRY alcRenderSamplesSOFT(ALCdevice *device, ALCvoid *buffer, ALCsizei samples) noexcept
 {
-    if(!device || device->Type != DeviceType::Loopback)
+    if(!device || device->Type != DeviceType::Loopback) UNLIKELY
         alcSetError(device, ALC_INVALID_DEVICE);
-    else if(samples < 0 || (samples > 0 && buffer == nullptr))
+    else if(samples < 0 || (samples > 0 && buffer == nullptr)) UNLIKELY
         alcSetError(device, ALC_INVALID_VALUE);
     else
         device->renderSamples(buffer, static_cast<uint>(samples), device->channelsFromFmt());
diff --git a/common/threads.h b/common/threads.h
index 62d80828..1ef037bb 100644
--- a/common/threads.h
+++ b/common/threads.h
@@ -1,19 +1,6 @@
 #ifndef AL_THREADS_H
 #define AL_THREADS_H
 
-#if defined(__GNUC__) && defined(__i386__)
-/* force_align_arg_pointer may be required for proper stack alignment when SSE
- * code is used. GCC generates code with the assumption the stack pointer is
- * suitably aligned, while some systems (Windows, QNX) do not guarantee non-
- * exported functions will be properly aligned when called externally, and
- * older apps for other systems may have been built with a lower stack
- * alignment than expected by newer builds.
- */
-#define FORCE_ALIGN __attribute__((force_align_arg_pointer))
-#else
-#define FORCE_ALIGN
-#endif
-
 #if defined(__APPLE__)
 #include <AvailabilityMacros.h>
 #include <TargetConditionals.h>
diff --git a/config.h.in b/config.h.in
index d1cf0395..20df5b46 100644
--- a/config.h.in
+++ b/config.h.in
@@ -1,3 +1,6 @@
+/* Define the alignment attribute for externally callable functions. */
+#define FORCE_ALIGN @ALSOFT_FORCE_ALIGN@
+
 /* Define if deprecated EAX extensions are enabled */
 #cmakedefine ALSOFT_EAX