arm32 cross-compilation with LTO needs lld-16

Summary: .

Reviewed By: avp

Differential Revision: D79003256

fbshipit-source-id: 3f490b195acde29ef7690f70f5630e6b45c51bd9

Author: Tzvetan Mikov

armhf/arm-linux-gnueabihf.toolchain.cmake

@@ -18,3 +18,7 @@ set(CMAKE_ASM_COMPILER_TARGET arm-linux-gnueabihf)
 # Ensure the correct architecture is used and enable Thumb-2
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mthumb -march=armv7-a")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mthumb -march=armv7-a")
+# Use LLD for better LTO support
+set(CMAKE_EXE_LINKER_FLAGS "-fuse-ld=lld-16")
+set(CMAKE_SHARED_LINKER_FLAGS "-fuse-ld=lld-16")
+set(CMAKE_MODULE_LINKER_FLAGS "-fuse-ld=lld-16")

doc/CrossCompilation.md

@@ -57,6 +57,8 @@ For Emscripten, you can find an example from the `test-emscripten` job from `her
 
 ## Compiling and Running ARM32 Static Hermes from ARM64
 
+On the ARM64 Linux machine you need clang-16 and lld-16.
+
 On the ARM64 Linux machine on which you're compiling:
 ```
 # Add architecture