[compiler-rt] dbb4f90 - [compiler-rt] Don't link builtins against the CRT on Windows (#70675)

[via llvm-commits]

Author: David Truby
Date: 2023-10-31T12:51:38Z
New Revision: dbb4f90252d19878d08a8dbe25d101d6c7af1f57

URL: https://github.com/llvm/llvm-project/commit/dbb4f90252d19878d08a8dbe25d101d6c7af1f57
DIFF: https://github.com/llvm/llvm-project/commit/dbb4f90252d19878d08a8dbe25d101d6c7af1f57.diff

LOG: [compiler-rt] Don't link builtins against the CRT on Windows (#70675)

compiler-rt/builtins doesn't depend on anything from the CRT but
currently links against it and embeds a `/defaultlib:msvcrt` in the
`.lib` file, forcing anyone linking against it to also link against that
specific CRT. This isn't necessary as the end user can just choose which
CRT they want to use independently.

Added: 
    

Modified: 
    compiler-rt/cmake/builtin-config-ix.cmake
    compiler-rt/lib/builtins/CMakeLists.txt

Removed: 
    


################################################################################
diff  --git a/compiler-rt/cmake/builtin-config-ix.cmake b/compiler-rt/cmake/builtin-config-ix.cmake
index e91e3923a756c53..9de05bb298efa13 100644
--- a/compiler-rt/cmake/builtin-config-ix.cmake
+++ b/compiler-rt/cmake/builtin-config-ix.cmake
@@ -18,6 +18,7 @@ builtin_check_c_compiler_flag(-fno-profile-generate COMPILER_RT_HAS_FNO_PROFILE_
 builtin_check_c_compiler_flag(-fno-profile-instr-generate COMPILER_RT_HAS_FNO_PROFILE_INSTR_GENERATE_FLAG)
 builtin_check_c_compiler_flag(-fno-profile-instr-use COMPILER_RT_HAS_FNO_PROFILE_INSTR_USE_FLAG)
 builtin_check_c_compiler_flag(-Wno-pedantic         COMPILER_RT_HAS_WNO_PEDANTIC)
+builtin_check_c_compiler_flag(/Zl COMPILER_RT_HAS_ZL_FLAG)
 
 builtin_check_c_compiler_source(COMPILER_RT_HAS_ATOMIC_KEYWORD
 "

diff  --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
index a705486e2d3c842..360fdb0e99b57be 100644
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -761,6 +761,12 @@ else ()
 
   append_list_if(COMPILER_RT_HAS_STD_C11_FLAG -std=c11 BUILTIN_CFLAGS)
 
+  # Don't embed directives for picking any specific CRT
+  if (MSVC)
+    set(CMAKE_MSVC_RUNTIME_LIBRARY "")
+    append_list_if(COMPILER_RT_HAS_ZL_FLAG /Zl BUILTIN_CFLAGS)
+  endif()
+
   # These flags would normally be added to CMAKE_C_FLAGS by the llvm
   # cmake step. Add them manually if this is a standalone build.
   if(COMPILER_RT_STANDALONE_BUILD)