[compiler-rt] [compiler-rt] Don't explicitly ad-hoc code sign dylibs if using Apple's new linker (PR #88323)

[Mark Rowe via llvm-commits]

https://github.com/bdash created https://github.com/llvm/llvm-project/pull/88323

Apple's new linker reports itself as ld rather than ld64 and does not match the version detection regex.

Invert the logic to look only for older versions of ld64. This ensures the runtime dylibs are left with a linker-generated code signature that tools such as `strip` will preserve.


>From 4a240fce8ea934b27a9b8556358e7534c54bcc0c Mon Sep 17 00:00:00 2001
From: Mark Rowe <markrowe at chromium.org>
Date: Wed, 10 Apr 2024 14:36:51 -0700
Subject: [PATCH] [compiler-rt] Don't explicitly ad-hoc code sign dylibs if
 using Apple's new linker

Apple's new linker reports itself as ld rather than ld64 and does not
match the version detection regex. Invert the logic to look only for
older versions of ld64.

This ensures the runtime dylibs are left with a linker-generated code
signature that tools such as `strip` will preserve.
---
 compiler-rt/cmake/Modules/AddCompilerRT.cmake | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/compiler-rt/cmake/Modules/AddCompilerRT.cmake b/compiler-rt/cmake/Modules/AddCompilerRT.cmake
index e0400a8ea95222..dc36f16c661c2c 100644
--- a/compiler-rt/cmake/Modules/AddCompilerRT.cmake
+++ b/compiler-rt/cmake/Modules/AddCompilerRT.cmake
@@ -405,11 +405,14 @@ function(add_compiler_rt_runtime name type)
         if (HAD_ERROR)
           message(FATAL_ERROR "${CMAKE_LINKER} failed with status ${HAD_ERROR}")
         endif()
-        set(NEED_EXPLICIT_ADHOC_CODESIGN 1)
+        set(NEED_EXPLICIT_ADHOC_CODESIGN 0)
+        # Apple introduced a new linker by default in Xcode 15. This linker reports itself as ld
+        # rather than ld64 and does not match this version regex. That's ok since it never needs
+        # the explicit ad-hoc code signature.
         if ("${LD_V_OUTPUT}" MATCHES ".*ld64-([0-9.]+).*")
           string(REGEX REPLACE ".*ld64-([0-9.]+).*" "\\1" HOST_LINK_VERSION ${LD_V_OUTPUT})
-          if (HOST_LINK_VERSION VERSION_GREATER_EQUAL 609)
-            set(NEED_EXPLICIT_ADHOC_CODESIGN 0)
+          if (HOST_LINK_VERSION VERSION_LESS 609)
+            set(NEED_EXPLICIT_ADHOC_CODESIGN 1)
           endif()
         endif()
         if (NEED_EXPLICIT_ADHOC_CODESIGN)