[lldb] [llvm] [cmake] Prevent implicitly passing `-no_exported_symbols` (PR #87846)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Cyndy Ishida (cyndyishida)

<details>
<summary>Changes</summary>

* It is possible to setup llvm-project builds without going through `llvm/CMakeList.txt` so the fatal error handling should be smarter.
* Disable option on Apple style lldb-linux builds.

---
Full diff: https://github.com/llvm/llvm-project/pull/87846.diff


2 Files Affected:

- (modified) lldb/cmake/caches/Apple-lldb-Linux.cmake (+1) 
- (modified) llvm/cmake/modules/AddLLVM.cmake (+7-1) 


``````````diff
diff --git a/lldb/cmake/caches/Apple-lldb-Linux.cmake b/lldb/cmake/caches/Apple-lldb-Linux.cmake
index b2d3cf595fe18d..9258f01e2ec26a 100644
--- a/lldb/cmake/caches/Apple-lldb-Linux.cmake
+++ b/lldb/cmake/caches/Apple-lldb-Linux.cmake
@@ -1,4 +1,5 @@
 include(${CMAKE_CURRENT_LIST_DIR}/Apple-lldb-base.cmake)
+set(LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES ON CACHE BOOL "")
 
 set(LLVM_DISTRIBUTION_COMPONENTS
   lldb
diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 81398ddb5c92e3..693fd5669f63f9 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -1038,9 +1038,15 @@ macro(add_llvm_executable name)
     add_llvm_symbol_exports( ${name} ${LLVM_EXPORTED_SYMBOL_FILE} )
   endif(LLVM_EXPORTED_SYMBOL_FILE)
 
-  if (NOT LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES AND LLVM_LINKER_SUPPORTS_NO_EXPORTED_SYMBOLS)
+  if (DEFINED LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES AND 
+      NOT LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES)
+    if(LLVM_LINKER_SUPPORTS_NO_EXPORTED_SYMBOLS)
       set_property(TARGET ${name} APPEND_STRING PROPERTY
         LINK_FLAGS " -Wl,-no_exported_symbols")
+    else()
+      message(FATAL_ERROR
+        "LLVM_ENABLE_EXPORTED_SYMBOLS_IN_EXECUTABLES cannot be disabled when linker does not support \"-no_exported_symbols\"")
+    endif()
   endif()
 
   if (LLVM_LINK_LLVM_DYLIB AND NOT ARG_DISABLE_LLVM_LINK_LLVM_DYLIB)

``````````

</details>


https://github.com/llvm/llvm-project/pull/87846