From 007e90e8c0a9176e16e70861d87dc7f883cc78ba Mon Sep 17 00:00:00 2001
From: Brecht Van Lommel <brecht@blender.org>
Date: Fri, 18 Sep 2020 17:07:11 +0200
Subject: Fix T78793, T79707: Cycles crash on macOS with older CPUs

Embree static libraries need additional linking flags to avoid SSE and
AVX symbols getting mixed up.
---
 build_files/cmake/Modules/FindEmbree.cmake      |  2 +-
 build_files/cmake/platform/platform_apple.cmake | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

(limited to 'build_files')

diff --git a/build_files/cmake/Modules/FindEmbree.cmake b/build_files/cmake/Modules/FindEmbree.cmake
index 2b3cd8e20c4..bc82d5c333a 100644
--- a/build_files/cmake/Modules/FindEmbree.cmake
+++ b/build_files/cmake/Modules/FindEmbree.cmake
@@ -37,9 +37,9 @@ FIND_PATH(EMBREE_INCLUDE_DIR
 
 SET(_embree_FIND_COMPONENTS
   embree3
+  embree_sse42
   embree_avx
   embree_avx2
-  embree_sse42
   lexers
   math
   simd
diff --git a/build_files/cmake/platform/platform_apple.cmake b/build_files/cmake/platform/platform_apple.cmake
index 11628da39a7..6bcb3ef5d8c 100644
--- a/build_files/cmake/platform/platform_apple.cmake
+++ b/build_files/cmake/platform/platform_apple.cmake
@@ -392,6 +392,16 @@ endif()
 if(WITH_CYCLES_EMBREE)
   find_package(Embree 3.8.0 REQUIRED)
   set(PLATFORM_LINKFLAGS "${PLATFORM_LINKFLAGS} -Xlinker -stack_size -Xlinker 0x100000")
+
+  # Embree static library linking can mix up SSE and AVX symbols, causing
+  # crashes on macOS systems with older CPUs that don't have AVX. Using
+  # force load avoids that. The Embree shared library does not suffer from
+  # this problem, precisely because linking a shared library uses force load.
+  set(_embree_libraries_force_load)
+  foreach(_embree_library ${EMBREE_LIBRARIES})
+    list(APPEND _embree_libraries_force_load "-Wl,-force_load,${_embree_library}")
+  endforeach()
+  set(EMBREE_LIBRARIES ${_embree_libraries_force_load})
 endif()
 
 if(WITH_OPENIMAGEDENOISE)
-- 
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