[CMake] Don't set <PROJECT>_STANDALONE_BUILD

[phosek]

Summary

We shouldn't be treating runtimes builds as standalone builds since
we have enough of the context loaded into the runtimes environment.

[smeenai]

LGTM, thanks! I think this makes more sense than before.

[beanz]

I know this is an old change, but there are actually some big problems with this. Compiler-RT in particular uses COMPILER_RT_STANDALONE_BUILD=Off to basically mean clang is a target in-tree to depend on. This completely breaks being able to run the compiler-rt tests from the runtimes directory because a bunch of the tests add dependencies on clang. See clang_compile and its uses in CompilerRTCompile.cmake.

compiler-rt/trunk/cmake/Modules/AddCompilerRT.cmake

if(NOT COMPILER_RT_LIBCXX_PATH)
     message(FATAL_ERROR "libcxx not found!")
   endif()
 
   cmake_parse_arguments(LIBCXX "USE_TOOLCHAIN" "" "DEPS;CFLAGS;CMAKE_ARGS" ${ARGN})
 
   if(LIBCXX_USE_TOOLCHAIN)
     set(compiler_args -DCMAKE_C_COMPILER=${COMPILER_RT_TEST_COMPILER}
                       -DCMAKE_CXX_COMPILER=${COMPILER_RT_TEST_CXX_COMPILER})
-    if(NOT COMPILER_RT_STANDALONE_BUILD)
+    if(NOT COMPILER_RT_STANDALONE_BUILD AND NOT RUNTIMES_BUILD)
       set(toolchain_deps $<TARGET_FILE:clang>)
       set(force_deps DEPENDS $<TARGET_FILE:clang>)
     endif()
   else()
     set(compiler_args -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
                       -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER})
   endif()
 

llvm/trunk/runtimes/CMakeLists.txt

if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
 
   # Setting these variables will allow the sub-build to put their outputs into
   # the library and bin directories of the top-level build.
   set(LLVM_LIBRARY_OUTPUT_INTDIR ${LLVM_LIBRARY_DIR})
   set(LLVM_RUNTIME_OUTPUT_INTDIR ${LLVM_TOOLS_BINARY_DIR})
 
   # This variable makes sure that e.g. llvm-lit is found.
   set(LLVM_MAIN_SRC_DIR ${LLVM_BUILD_MAIN_SRC_DIR})
+  set(LLVM_CMAKE_PATH ${LLVM_MAIN_SRC_DIR}/cmake/modules)
 
   if(APPLE)
     set(LLVM_ENABLE_LIBCXX ON CACHE BOOL "")
   endif()
 
   set(SAFE_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
   set(SAFE_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
 
if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
   set(LLVM_COMPILER_CHECKED ON)
   # Enable warnings, otherwise -w gets added to the cflags by HandleLLVMOptions
   # resulting in unjustified successes by check_cxx_compiler_flag.
   set(LLVM_ENABLE_WARNINGS ON)
 
   # Handle common options used by all runtimes.
   include(AddLLVM)
   include(HandleLLVMOptions)
+  include(FindPythonInterp)
 
   set(CMAKE_REQUIRED_FLAGS ${SAFE_CMAKE_REQUIRED_FLAGS})
   set(CMAKE_REQUIRED_LIBRARIES ${SAFE_CMAKE_REQUIRED_LIBRARIES})
 
+  # This can be used to detect whether we're in the runtimes build.
+  set(RUNTIMES_BUILD ON)
+
   foreach(entry ${runtimes})
     get_filename_component(projName ${entry} NAME)
 
     # TODO: Clean this up as part of an interface standardization
     string(REPLACE "-" "_" canon_name ${projName})
     string(TOUPPER ${canon_name} canon_name)
-    # The subdirectories need to treat this as standalone builds
-    set(${canon_name}_STANDALONE_BUILD On)
 
     if(LLVM_RUNTIMES_LIBDIR_SUFFIX)
       set(${canon_name}_LIBDIR_SUFFIX "${LLVM_RUNTIMES_LIBDIR_SUFFIX}" CACHE STRING "" FORCE)
     endif()
 
     # Setting a variable to let sub-projects detect which other projects
     # will be included under here.
-    set(HAVE_${canon_name} On)
+    set(HAVE_${canon_name} ON)
   endforeach()
 
   # We do this in two loops so that HAVE_* is set for each runtime before the
   # other runtimes are added.
   foreach(entry ${runtimes})
     get_filename_component(projName ${entry} NAME)
 
     # Between each sub-project we want to cache and clear the LIT properties