From 9ffd4130087ac60424d5b71708e5e1c47dafb475 Mon Sep 17 00:00:00 2001
From: Ankit Meel <ankitjmeel@gmail.com>
Date: Wed, 12 Apr 2023 17:01:53 +0530
Subject: [PATCH] macOS/Linker: support mold and lld

If someone buys "sold", mold should work on macOS too.
With lld, Blender (700 MB) intel i5: 26s -> 17s.

Pull Request #106843
---
 CMakeLists.txt                                |  8 +++---
 .../cmake/platform/platform_apple.cmake       | 25 +++++++++++++++++++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2f8e3460f09..a31a8e92485 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -645,15 +645,15 @@ if(WIN32)
 endif()
 
 # Compiler tool-chain.
-if(UNIX AND NOT APPLE)
+if(UNIX)
   if(CMAKE_COMPILER_IS_GNUCC)
     option(WITH_LINKER_GOLD "Use ld.gold linker which is usually faster than ld.bfd" ON)
     mark_as_advanced(WITH_LINKER_GOLD)
-    option(WITH_LINKER_LLD "Use ld.lld linker which is usually faster than ld.gold" OFF)
-    mark_as_advanced(WITH_LINKER_LLD)
   endif()
   if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
-    option(WITH_LINKER_MOLD "Use ld.mold linker which is usually faster than ld.gold & ld.lld." OFF)
+    option(WITH_LINKER_LLD "Use ld.lld linker which is usually faster than ld.gold" OFF)
+    mark_as_advanced(WITH_LINKER_LLD)
+    option(WITH_LINKER_MOLD "Use ld.mold linker which is usually faster than ld.gold & ld.lld. Needs \"sold\" subscription on macOS." OFF)
     mark_as_advanced(WITH_LINKER_MOLD)
   endif()
 endif()
diff --git a/build_files/cmake/platform/platform_apple.cmake b/build_files/cmake/platform/platform_apple.cmake
index 942e86f617d..20114191c52 100644
--- a/build_files/cmake/platform/platform_apple.cmake
+++ b/build_files/cmake/platform/platform_apple.cmake
@@ -451,6 +451,31 @@ if(WITH_COMPILER_CCACHE)
   endif()
 endif()
 
+unset(_custom_LINKER_FUSE_FLAG)
+if(WITH_LINKER_LLD)
+  find_program(LLD_PROGRAM ld.lld)
+  if(LLD_PROGRAM)
+    set(_custom_LINKER_FUSE_FLAG "-fuse-ld=lld")
+  else()
+    message(WARNING "LLD linker NOT found, disabling WITH_LINKER_LLD")
+    set(WITH_LINKER_LLD OFF)
+  endif()
+endif()
+if(WITH_LINKER_MOLD)
+  find_program(MOLD_PROGRAM mold)
+  if(MOLD_PROGRAM)
+    set(_custom_LINKER_FUSE_FLAG "-fuse-ld=mold")
+  else()
+    message(WARNING "Mold linker NOT found, disabling WITH_LINKER_MOLD")
+    set(WITH_LINKER_MOLD OFF)
+  endif()
+endif()
+
+if(_custom_LINKER_FUSE_FLAG)
+  add_link_options(${_custom_LINKER_FUSE_FLAG})
+endif()
+
+
 if(WITH_COMPILER_ASAN)
   list(APPEND PLATFORM_BUNDLED_LIBRARIES ${COMPILER_ASAN_LIBRARY})
 endif()