[clangd] Don't build clangd or run its tests when LLVM_ENABLE_THREADS is off, unless specifically directed to do so

[sammccall]

Summary

Introduce a new CLANGD_BUILD option, only default to true if threads are on.

(the name doesn't seem ideal, I'm trying to follow precedent of CLANGD_BUILD_XPC)

This is a bit of a mess because of the parallel unittest/ and test/ trees in
clang-tools-extra (clangd has three root directories).

I'd like to move clang-tools-extra/test/clangd -> clang-tools-extra/clangd/test etc,
but will do that afterwards.

[ilya-biryukov]

A better name could definitely be nice, e.g. BUILD_CLANGD would've been much nicer.
But the current one is also okayish, being consistent with existing names is a good reason to keep it that way.

CMakeLists.txt

13

NIT: maybe comment why we disable clangd with no threads?
Merely mentioning this configuration is not supported in clangd would be good enough.

Maybe it's just me, but I tend to find following cmake scripts really hard and even obvious comments make it much simpler.

[sammccall]

Superseded by rL360115

CMakeLists.txt

 if (NOT DEFINED CLANGD_BUILD_XPC)
   if(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
     set(CLANGD_BUILD_XPC_DEFAULT ON)
   else ()
     set(CLANGD_BUILD_XPC_DEFAULT OFF)
   endif ()
 
   set(CLANGD_BUILD_XPC ${CLANGD_BUILD_XPC_DEFAULT} CACHE BOOL "Build XPC Support For Clangd." FORCE)
 
   unset(CLANGD_BUILD_XPC_DEFAULT)
 endif ()
+# FIXME: move clangd to its own self-contained subtree and clean this up.
+option(CLANGD_BUILD "Build clangd" ${LLVM_ENABLE_THREADS})
 
 add_subdirectory(clang-apply-replacements)
 add_subdirectory(clang-reorder-fields)
 add_subdirectory(modularize)
 add_subdirectory(clang-tidy)
 add_subdirectory(clang-tidy-vs)
 
 add_subdirectory(clang-change-namespace)
 add_subdirectory(clang-doc)
 add_subdirectory(clang-include-fixer)
 add_subdirectory(clang-move)
 add_subdirectory(clang-query)
+if ( CLANGD_BUILD )
   add_subdirectory(clangd)
+endif()
 add_subdirectory(pp-trace)
 add_subdirectory(tool-template)
 
 # Add the common testsuite after all the tools.
 if(CLANG_INCLUDE_TESTS)
 add_subdirectory(test)
 add_subdirectory(unittests)
 endif()
 
 option(CLANG_TOOLS_EXTRA_INCLUDE_DOCS "Generate build targets for the Clang Extra Tools docs."
   ${LLVM_INCLUDE_DOCS})
 if( CLANG_TOOLS_EXTRA_INCLUDE_DOCS )
   add_subdirectory(docs)
 endif()
 

test/CMakeLists.txt

set(CLANG_TOOLS_TEST_DEPS
   # clang-tidy tests require it.
   clang-resource-headers
 
   clang-tidy
   # Clang-tidy tests need clang for building modules.
   clang
 )
 
+set(LLVM_UTILS_DEPS
+  FileCheck count not
+)
+foreach(dep ${LLVM_UTILS_DEPS})
+  if(TARGET ${dep})
+    list(APPEND CLANG_TOOLS_TEST_DEPS ${dep})
+  endif()
+endforeach()
+
+if ( CLANGD_BUILD )
   if(CLANGD_BUILD_XPC)
     list(APPEND CLANG_TOOLS_TEST_DEPS clangd-xpc-test-client)
   endif()
 
   set(CLANGD_TEST_DEPS
     clangd
     ClangdTests
     # clangd-related tools which don't have tests, add them to the test to make
     # sure we don't introduce new changes that break their compilations.
     clangd-indexer
     dexp
     )
 
-# Add lit test dependencies.
-set(LLVM_UTILS_DEPS
-  FileCheck count not
-)
-foreach(dep ${LLVM_UTILS_DEPS})
-  if(TARGET ${dep})
-    list(APPEND CLANGD_TEST_DEPS ${dep})
-  endif()
-endforeach()
-
   foreach(clangd_dep ${CLANGD_TEST_DEPS})
     list(APPEND CLANG_TOOLS_TEST_DEPS
          ${clangd_dep})
   endforeach()
 
+  set(CLANG_TOOLS_TEST_EXTRA_ARGS ${CLANG_TEST_EXTRA_ARGS} "-DCLANGD_BUILD=1")
+endif()
+
 add_lit_testsuite(check-clang-tools "Running the Clang extra tools' regression tests"
   ${CMAKE_CURRENT_BINARY_DIR}
   DEPENDS ${CLANG_TOOLS_TEST_DEPS}
   ARGS ${CLANG_TOOLS_TEST_EXTRA_ARGS}
   )
 
 set_target_properties(check-clang-tools PROPERTIES FOLDER "Clang extra tools' tests")
 
+if ( CLANGD_BUILD )
   # Setup an individual test for building and testing clangd-only stuff.
   # Note: all clangd tests have been covered in check-clang-tools, this is a
   # convenient target for clangd developers.
   # Exclude check-clangd from check-all.
   set(EXCLUDE_FROM_ALL ON)
   add_lit_testsuite(check-clangd "Running the Clangd regression tests"
     ${CMAKE_CURRENT_BINARY_DIR}/Unit/clangd;${CMAKE_CURRENT_BINARY_DIR}/clangd
     DEPENDS ${CLANGD_TEST_DEPS}
+    ARGS -DCLANGD_BUILD=1
   )
   set_target_properties(check-clangd PROPERTIES FOLDER "Clangd tests")
   set(EXCLUDE_FROM_ALL OFF)
+endif()

test/clangd/lit.local.cfg

 import re
 # We rely on the default -std being derived from the filetype.
 # PS4 sets a different -std, and many tests break.
 # FIXME: make our tests less brittle instead.
 if re.match(r'.*-scei-ps4', config.target_triple):
   config.unsupported = True
+if 'CLANGD_BUILD' not in lit_config.params:
+  config.unsupported = True

unittests/CMakeLists.txt

 
 add_subdirectory(clang-apply-replacements)
 add_subdirectory(clang-change-namespace)
 add_subdirectory(clang-doc)
 add_subdirectory(clang-include-fixer)
 add_subdirectory(clang-move)
 add_subdirectory(clang-query)
 add_subdirectory(clang-tidy)
+if (CLANGD_BUILD)
   add_subdirectory(clangd)
+endif()