From de2336247c7243be42e23ef0b343d7561f4fc886 Mon Sep 17 00:00:00 2001
From: Henry Jiang <henry_jiang2@apple.com>
Date: Tue, 14 Apr 2026 10:48:14 -0700
Subject: [PATCH] [Darwin] Externalize debug info

---
 CMakeLists.txt                |  4 ++++
 cmake/modules/TestSuite.cmake | 16 ++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0c3567e7db7b..dfd6d84e8442 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -180,6 +180,10 @@ option(TEST_SUITE_PROFILE_USE
       "Add apropriate -fprofile-instr-use to CFLAGS/CXXFLAGS for each benchmark"
       OFF)
 
+option(TEST_SUITE_EXTERNALIZE_DEBUGINFO
+      "Generate dSYM files for executables (Darwin only)"
+      OFF)
+
 # When running the test-suite in diagnosis mode, use these flags passed by
 # LNT to gather data, for examples -ftime-report, or -mllvm -stats. This way
 # the user specified CMAKE_C_FLAGS etc. need not be changed.
diff --git a/cmake/modules/TestSuite.cmake b/cmake/modules/TestSuite.cmake
index a8df8b78f841..b677b8301e87 100644
--- a/cmake/modules/TestSuite.cmake
+++ b/cmake/modules/TestSuite.cmake
@@ -63,6 +63,22 @@ function(llvm_test_executable_no_test target)
   set_property(GLOBAL APPEND PROPERTY TEST_SUITE_TARGETS ${target})
   test_suite_add_build_dependencies(${target})
 
+  if(TEST_SUITE_EXTERNALIZE_DEBUGINFO AND APPLE)
+    if(CMAKE_C_FLAGS MATCHES "-flto"
+      OR CMAKE_CXX_FLAGS MATCHES "-flto"
+      OR CMAKE_C_FLAGS_RELEASE MATCHES "-flto"
+      OR CMAKE_CXX_FLAGS_RELEASE MATCHES "-flto")
+      set(lto_object ${CMAKE_CURRENT_BINARY_DIR}/${target}-lto.o)
+      set_property(TARGET ${target} APPEND_STRING PROPERTY
+        LINK_FLAGS " -Wl,-object_path_lto,${lto_object}")
+    endif()
+    if(NOT CMAKE_DSYMUTIL)
+      set(CMAKE_DSYMUTIL xcrun dsymutil)
+    endif()
+    add_custom_command(TARGET ${target} POST_BUILD
+      COMMAND ${CMAKE_DSYMUTIL} $<TARGET_FILE:${target}>)
+  endif()
+
   if(TEST_SUITE_LLVM_SIZE)
     add_custom_command(TARGET ${target} POST_BUILD
       COMMAND ${TEST_SUITE_LLVM_SIZE} --format=sysv $<SHELL_PATH:$<TARGET_FILE:${target}>>