[llvm] llvm: Use add_link_options for stack size flags (PR #195034)

[Fabrice de Gans via llvm-commits]

https://github.com/Steelskin created https://github.com/llvm/llvm-project/pull/195034

Previously, LLVM was directly editing `CMAKE_EXE_LINKER_FLAGS`. This is a user-facing CMake cache variable not meant to be modified by project code. This was causing issues for downstream consumers building non-C/C++ targets as part of the LLVM build.

Modern CMake provides `add_link_options()`, a cleaner way to set linker flags that propagate to every target in a directory tree.

Generator expressions and the `LINKER:` prefix syntax ensure that this is only applied to executable targets with the proper language and linker argument wrapping.

>From ac13bec919569ffcd9f027144187a2a449597147 Mon Sep 17 00:00:00 2001
From: Fabrice de Gans <steelskin at gmail.com>
Date: Tue, 28 Apr 2026 11:53:17 +0200
Subject: [PATCH] llvm: Use add_link_options for stack size flags

Previously, LLVM was directly editing `CMAKE_EXE_LINKER_FLAGS`. This is a
user-facing CMake cache variable not meant to be modified by project
code. This was causing issues for downstream consumers building
non-C/C++ targets as part of the LLVM build.

Modern CMake provides `add_link_options()`, a cleaner way to set linker
flags that propagate to every target in a directory tree.

Generator expressions and the `LINKER:` prefix syntax ensure that this
is only applied to executable targets with the proper language and
linker argument wrapping.
---
 llvm/cmake/modules/HandleLLVMOptions.cmake | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index 5f1d68762c038..75bd8ed11e1ba 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -570,14 +570,15 @@ if( MSVC_IDE )
 endif()
 
 # set stack reserved size to ~10MB
+set(_is_exe "$<STREQUAL:$<TARGET_PROPERTY:TYPE>,EXECUTABLE>")
 if(MSVC)
   # CMake previously automatically set this value for MSVC builds, but the
   # behavior was changed in CMake 2.8.11 (Issue 12437) to use the MSVC default
   # value (1 MB) which is not enough for us in tasks such as parsing recursive
   # C++ templates in Clang.
-  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${CMAKE_CXX_LINKER_WRAPPER_FLAG}/STACK:10000000")
+  add_link_options("$<${_is_exe}:LINKER:/STACK:10000000>")
 elseif(MINGW OR CYGWIN)
-  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,--stack,16777216")
+  add_link_options("$<${_is_exe}:LINKER:--stack,16777216>")
 
   # Pass -mbig-obj to mingw gas to avoid COFF 2**16 section limit.
   if (NOT CMAKE_CXX_COMPILER_ID MATCHES "Clang")