[lldb/CMake] Make check-lldb-* work for the standalone build.

[JDevlieghere]

Summary

In order to run check-lldb-* we need the correct map_config directives in
llvm-lit. Because this is a standalone build, LLVM doesn't know about LLDB,
we need to build our own and tell LLVM to use it.

I tested this for both the standalone Ninja & Xcode standalone build.

[JDevlieghere]

Add missing context.

[xiaobai]

we need to build our own and tell LLVM to use it

To clarify, this means we'd be building our own llvm-lit and using that just for the LLDB test suite, correct?

[JDevlieghere]

In D76945#1946988, @xiaobai wrote:

we need to build our own and tell LLVM to use it

To clarify, this means we'd be building our own llvm-lit and using that just for the LLDB test suite, correct?

Yep, should I reword the comment?

[xiaobai]

In D76945#1947034, @JDevlieghere wrote:

In D76945#1946988, @xiaobai wrote:

we need to build our own and tell LLVM to use it

To clarify, this means we'd be building our own llvm-lit and using that just for the LLDB test suite, correct?

Yep, should I reword the comment?

I think it's a little confusing as-is. I'm not sure what you meant by "and tell LLVM to use it".

[labath]

sounds reasonable

lldb/test/CMakeLists.txt

 # Test runner infrastructure for LLDB. This configures the LLDB test trees
 # for use by Lit, and delegates to LLVM's lit test handlers.
 
+if(LLDB_BUILT_STANDALONE)
+  # In order to run check-lldb-* we need the correct map_config directives in
+  # llvm-lit. Because this is a standalone build, LLVM doesn't know about LLDB,
+  # and the lldb mappings are missing. We build our own llvm-lit, and tell LLVM
+  # to use the llvm-lit in the lldb build directory.
+  if (EXISTS ${LLVM_MAIN_SRC_DIR}/utils/llvm-lit)
+    set(LLVM_EXTERNAL_LIT ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/llvm-lit)
+  endif()
+endif()
+
 # Configure the build directory.
 set(LLDB_TEST_BUILD_DIRECTORY "${PROJECT_BINARY_DIR}/lldb-test-build.noindex" CACHE PATH "The build root for building tests.")
 
 # Configure and create module cache directories.
 set(LLDB_TEST_MODULE_CACHE_LLDB "${LLDB_TEST_BUILD_DIRECTORY}/module-cache-lldb" CACHE PATH "The Clang module cache used by the Clang embedded in LLDB while running tests.")
 set(LLDB_TEST_MODULE_CACHE_CLANG "${LLDB_TEST_BUILD_DIRECTORY}/module-cache-clang" CACHE PATH "The Clang module cache used by the Clang while building tests.")
 file(MAKE_DIRECTORY ${LLDB_TEST_MODULE_CACHE_LLDB})
 file(MAKE_DIRECTORY ${LLDB_TEST_MODULE_CACHE_CLANG})
add_lit_testsuite(check-lldb-lit "Running lldb lit test suite"
   ${CMAKE_CURRENT_BINARY_DIR}
   DEPENDS lldb-test-deps)
 set_target_properties(check-lldb-lit PROPERTIES FOLDER "lldb tests")
 
 add_custom_target(check-lldb)
 add_dependencies(check-lldb lldb-test-deps)
 set_target_properties(check-lldb PROPERTIES FOLDER "lldb misc")
 add_dependencies(check-lldb check-lldb-lit)
+
+if(LLDB_BUILT_STANDALONE)
+  # This has to happen *AFTER* add_lit_testsuite.
+  if (EXISTS ${LLVM_MAIN_SRC_DIR}/utils/llvm-lit)
+    add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/llvm-lit ${CMAKE_CURRENT_BINARY_DIR}/llvm-lit)
+  endif()
+endif()