LLVMProcessSources.cmake: Improve PARTIAL_SOURCES_INTENDED.

[chapuni]

Summary

The last non-partial-specified target can collect and check source files.

Case A:

llvm_add_library(foo PARTIAL_SOURCES_INTENDED ...)
llvm_add_library(bar PARTIAL_SOURCES_INTENDED ...)
llvm_add_library(baz ...)

baz checks source files in foo, bar, and baz.

Case B:

llvm_add_library(hoge PARTIAL_SOURCES_INTENDED ...)
llvm_add_library(fuga PARTIAL_SOURCES_INTENDED ...)
llvm_add_library(piyo PARTIAL_SOURCES_INTENDED ...)
llvm_check_source_file_list() # Explicitly checks sources in hoge, fuga, and piyo.

LLVMFuzzerCLI: [CMake] Prune the last PARTIAL_SOURCES_INTENDED to cover all sources.

[chapuni]

I have committed this since I thought this is a trivial change with one user.

llvm/cmake/modules/LLVMProcessSources.cmake

function(find_all_header_files hdrs_out additional_headerdirs)
 
   set( ${hdrs_out} ${all_headers} PARENT_SCOPE )
 endfunction(find_all_header_files)
 
 
 function(llvm_process_sources OUT_VAR)
   cmake_parse_arguments(ARG "PARTIAL_SOURCES_INTENDED" "" "ADDITIONAL_HEADERS;ADDITIONAL_HEADER_DIRS" ${ARGN})
   set(sources ${ARG_UNPARSED_ARGUMENTS})
-  if (NOT ARG_PARTIAL_SOURCES_INTENDED)
-    llvm_check_source_file_list(${sources})
-  endif()
 
   # This adds .td and .h files to the Visual Studio solution:
   add_td_sources(sources)
   find_all_header_files(hdrs "${ARG_ADDITIONAL_HEADER_DIRS}")
   if (hdrs)
     set_source_files_properties(${hdrs} PROPERTIES HEADER_FILE_ONLY ON)
   endif()
   set_source_files_properties(${ARG_ADDITIONAL_HEADERS} PROPERTIES HEADER_FILE_ONLY ON)
function(llvm_check_source_file_list)
 
   if(ARG_SOURCE_DIR)
     file(GLOB globbed
          "${ARG_SOURCE_DIR}/*.c" "${ARG_SOURCE_DIR}/*.cpp")
   else()
     file(GLOB globbed *.c *.cpp)
   endif()
 
+  set_property(DIRECTORY APPEND PROPERTY LLVM_SOURCE_FILES ${listed})
+  if (ARG_PARTIAL_SOURCES_INTENDED) # llvm_process_source's scope
+    return()
+  endif()
+  get_directory_property(listed LLVM_SOURCE_FILES)
+
   foreach(g ${globbed})
     get_filename_component(fn ${g} NAME)
     if(ARG_SOURCE_DIR)
       set(entry "${g}")
     else()
       set(entry "${fn}")
     endif()
     get_filename_component(gp ${g} REALPATH)