clang-tools-extra: Make test dependency on LLVMHello optional

[tstellar]

Summary

This fixes clang + clang-tools-extra standalone build after
36892727e4f19a60778e371d78f8fb09d8122c85.

[vtjnash]

Seems extra complexity, and less desirable to lose test coverage, when it seems the option may already be unreliable and soon to be deprecated by https://reviews.llvm.org/D119383. @MaskRay is that accurate?

[MaskRay]

In D120301#3346236, @vtjnash wrote:

Seems extra complexity, and less desirable to lose test coverage, when it seems the option may already be unreliable and soon to be deprecated by https://reviews.llvm.org/D119383. @MaskRay is that accurate?

Seems that D119383 that is not favored by Gentoo and RedHat.
I do not know whether we will be able to remove the standalone build mode.

[tstellar]

@vtjnash There hasn't been consensus on removing support for standalone builds yet, and I'm in favor of keeping them as are some other distribution maintainers.

[nikic]

clang-tools-extra/test/CMakeLists.txt

107

Shouldn't this be LLVMHello?

clang-tools-extra/test/CMakeLists.txt

 if (CMAKE_CFG_INTDIR STREQUAL ".")
   set(LLVM_BUILD_MODE ".")
 else ()
   set(LLVM_BUILD_MODE "%(build_mode)s")
 endif ()
 
 string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} CLANG_TOOLS_DIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
 
+if (TARGET LLVMHello)
+  set (LLVM_HAS_LLVM_HELLO 1)
+endif()
+
 llvm_canonicalize_cmake_booleans(
   CLANG_TIDY_ENABLE_STATIC_ANALYZER
   CLANG_PLUGIN_SUPPORT
   LLVM_INSTALL_TOOLCHAIN_ONLY
+  LLVM_HAS_LLVM_HELLO
   )
 
 configure_lit_site_cfg(
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
   ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg.py
   MAIN_CONFIG
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.cfg.py
   )
if(CLANG_BUILT_STANDALONE)
     if (EXISTS ${LLVM_MAIN_SRC_DIR}/lib/Transforms/Hello
        AND NOT TARGET LLVMHello)
       add_subdirectory(${LLVM_MAIN_SRC_DIR}/lib/Transforms/Hello
         lib/Transforms/Hello)
     endif()
   endif()
 
   if(TARGET CTTestTidyModule)
-      list(APPEND CLANG_TOOLS_TEST_DEPS CTTestTidyModule LLVMHello)
+      list(APPEND CLANG_TOOLS_TEST_DEPS CTTestTidyModule)
+      if (TARGET  LLVMHello)
+        list(APPEND CLANG_TOOLS_TEST_DEPS CTTestTidyModule)
+      endif()
       target_include_directories(CTTestTidyModule PUBLIC BEFORE "${CLANG_TOOLS_SOURCE_DIR}")
       if(CLANG_PLUGIN_SUPPORT AND (WIN32 OR CYGWIN))
         set(LLVM_LINK_COMPONENTS
           Support
         )
       endif()
   endif()
 endif()

clang-tools-extra/test/clang-tidy/CTTestTidyModule.cpp

-// REQUIRES: plugins
+// REQUIRES: plugins, llvm-hello
 // RUN: clang-tidy -checks='-*,mytest*' --list-checks -load %llvmshlibdir/CTTestTidyModule%pluginext -load %llvmshlibdir/LLVMHello%pluginext | FileCheck --check-prefix=CHECK-LIST %s
 // CHECK-LIST: Enabled checks:
 // CHECK-LIST-NEXT:    mytest1
 // CHECK-LIST-NEXT:    mytest2
 // RUN: clang-tidy -checks='-*,mytest*,misc-definitions-in-headers' -load %llvmshlibdir/CTTestTidyModule%pluginext /dev/null -- -xc 2>&1 | FileCheck %s
 // CHECK: 3 warnings generated.
 // CHECK-NEXT: warning: mytest success [misc-definitions-in-headers,mytest1,mytest2]
 

clang-tools-extra/test/lit.cfg.py

 config.substitutions.append(('%clangd-benchmark-dir',
                              '%s' % (clangd_benchmarks_dir)))
 config.substitutions.append(('%llvmshlibdir', config.clang_libs_dir))
 config.substitutions.append(('%pluginext', config.llvm_plugin_ext))
 
 # Plugins (loadable modules)
 if config.has_plugins and config.llvm_plugin_ext:
     config.available_features.add('plugins')
+
+if config.has_llvm_hello:
+    config.available_features.add("llvm-hello")

clang-tools-extra/test/lit.site.cfg.py.in

 @LIT_SITE_CFG_IN_HEADER@
 
 import sys
 
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
 config.llvm_plugin_ext = "@LLVM_PLUGIN_EXT@"
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.clang_tools_binary_dir = "@CLANG_TOOLS_BINARY_DIR@"
 config.clang_tools_dir = "@CLANG_TOOLS_DIR@"
 config.clang_libs_dir = "@SHLIBDIR@"
 config.python_executable = "@Python3_EXECUTABLE@"
 config.target_triple = "@TARGET_TRIPLE@"
 config.clang_tidy_staticanalyzer = @CLANG_TIDY_ENABLE_STATIC_ANALYZER@
 config.has_plugins = @CLANG_PLUGIN_SUPPORT@ & ~@LLVM_INSTALL_TOOLCHAIN_ONLY@
+config.has_llvm_hello = @LLVM_HAS_LLVM_HELLO@
 
 # Support substitution of the tools and libs dirs with user parameters. This is
 # used when we can't determine the tool dir at configuration time.
 try:
     config.clang_tools_dir = config.clang_tools_dir % lit_config.params
     config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
     config.llvm_libs_dir = config.llvm_libs_dir % lit_config.params
 except KeyError: