[PATCH] D89356: [cmake] Limit missing external lit warning to be shown once

[Dave Lee via Phabricator via llvm-commits]

kastiglione created this revision.
kastiglione added reviewers: JDevlieghere, aprantl.
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When using a custom `LLVM_EXTERNAL_LIT`, it's possible the file may not exist at the CMake is generating the build. One example is LLDB standalone builds. When the external lit doesn't exist, a warning message is emitted, but the warning is printed once for every single lit target. This produces many redundant warnings.

This changes the warning to only be emitted once, controlled by a CACHE variable.

Other options are:

1. remove the warning
2. have callers pass an option to silence the warning if desired

See https://reviews.llvm.org/D76945 for some context.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D89356

Files:
  llvm/cmake/modules/AddLLVM.cmake


Index: llvm/cmake/modules/AddLLVM.cmake
===================================================================
--- llvm/cmake/modules/AddLLVM.cmake
+++ llvm/cmake/modules/AddLLVM.cmake
@@ -1659,7 +1659,10 @@
         set(${base_dir} ${LIT_BASE_DIR} PARENT_SCOPE)
         return()
       else()
-        message(WARNING "LLVM_EXTERNAL_LIT set to ${LLVM_EXTERNAL_LIT}, but the path does not exist.")
+        if (NOT DEFINED CACHE{LLVM_EXTERNAL_LIT_MISSING_WARNED_ONCE})
+          message(WARNING "LLVM_EXTERNAL_LIT set to ${LLVM_EXTERNAL_LIT}, but the path does not exist.")
+          set(LLVM_EXTERNAL_LIT_MISSING_WARNED_ONCE YES CACHE BOOL "")
+        endif()
       endif()
     endif()
   endif()


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