[CMake] Detect properly new linker introduced in Xcode 15

[edymtt]

As explained in 1, this linker is functionally equivalent to the classic one (ld64)
for build system purposes -- in particular to enable the use of order files to link
clang. For this reason, in addition to fixing the detection rename
LLVM_LINKER_IS_LD64 to LLVM_LINKER_IS_APPLE to make the result of
such detection more clear -- this should not cause any issue to downstream
users, from a quick search in SourceGraph 2, only Swift uses the value of
this variable (which I will take care of updating in due time).

rdar://120740222

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[llvmbot]

@llvm/pr-subscribers-clang

Author: Eric Miotto (edymtt)

Changes

This linker is functionally equivalent to the classic one (ld64) for build system purposes -- in particular to enable the use of order files to link clang.
For this reason, in addition to fixing the detection rename LLVM_LINKER_IS_LD64 to LLVM_LINKER_IS_APPLE to make the result of such detection more clear -- this should not cause any issue to downstream users, from a quick serch in
Sourcegraph only Swift uses the value of this variable (which I will take care of updating in due time).

rdar://120740222

---

Full diff: https://github.com/llvm/llvm-project/pull/77806.diff

2 Files Affected:

• (modified) clang/tools/driver/CMakeLists.txt (+2-2)
• (modified) llvm/cmake/modules/AddLLVM.cmake (+3-3)

diff --git a/clang/tools/driver/CMakeLists.txt b/clang/tools/driver/CMakeLists.txt
index 2182486f93a555..d70b92b0984e52 100644
--- a/clang/tools/driver/CMakeLists.txt
+++ b/clang/tools/driver/CMakeLists.txt
@@ -103,10 +103,10 @@ if (APPLE)
 endif()
 
 if(CLANG_ORDER_FILE AND
-    (LLVM_LINKER_IS_LD64 OR LLVM_LINKER_IS_GOLD OR LLVM_LINKER_IS_LLD))
+    (LLVM_LINKER_IS_APPLE OR LLVM_LINKER_IS_GOLD OR LLVM_LINKER_IS_LLD))
   include(LLVMCheckLinkerFlag)
 
-  if (LLVM_LINKER_IS_LD64 OR (LLVM_LINKER_IS_LLD AND APPLE))
+  if (LLVM_LINKER_IS_APPLE OR (LLVM_LINKER_IS_LLD AND APPLE))
     set(LINKER_ORDER_FILE_OPTION "-Wl,-order_file,${CLANG_ORDER_FILE}")
   elseif (LLVM_LINKER_IS_GOLD)
     set(LINKER_ORDER_FILE_OPTION "-Wl,--section-ordering-file,${CLANG_ORDER_FILE}")
diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 14c0837c35964d..5e989618552824 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -211,10 +211,10 @@ if (NOT DEFINED LLVM_LINKER_DETECTED AND NOT WIN32)
     )
 
   if(APPLE)
-    if("${stderr}" MATCHES "PROJECT:ld64")
+    if("${stderr}" MATCHES "PROGRAM:ld")
       set(LLVM_LINKER_DETECTED YES CACHE INTERNAL "")
-      set(LLVM_LINKER_IS_LD64 YES CACHE INTERNAL "")
-      message(STATUS "Linker detection: ld64")
+      set(LLVM_LINKER_IS_APPLE YES CACHE INTERNAL "")
+      message(STATUS "Linker detection: Apple")
     elseif("${stderr}" MATCHES "^LLD" OR
            "${stdout}" MATCHES "^LLD")
       set(LLVM_LINKER_DETECTED YES CACHE INTERNAL "")

[edymtt]

macOS testing triggered on swiftlang#7962

[edymtt]

(Rebased on top of recent changes to take format changes in clang/docs/HLSL/FunctionCalls.rst)

[ldionne]

The CI failures seem unrelated. I'll merge when the hidden e-mail address issue has been resolved.

[edymtt]

That issue should now be addressed in 1530d4c (for future reference, this concern is discussed in LLVM Discourse, not in the contribution documentation)

Also matched the commit message to your edits (which I forgot to thank you for, the format changes improve the overall readability)