[cmake] Expand $(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME) in LLVM CMake paths.

In order to support swapping build types without reconfiguring, Swift's CMake
generated Xcode project has one directory for each cmake build type. This
behavior is implemented by placing in variables for Xcode to expand at build
time. This causes issues with our build, namely that our cmake scripts like to
"poke" around the LLVM build directory at configure time. Since the xcode
variables from the commit title are not expanded, failures occur since the
unexpanded paths do not exist.

This patch fixes this problem by expanding out those variables at configure time
from specific LLVM paths. This is essentially tieing LLVM to the specific
build-script build mode used. This is reasonable since we do not support
building in Xcode for configurations that were not selected at build-script
time.

rdar://27062396

Author: gottesmm

cmake/modules/SwiftSharedCMakeConfig.cmake

@@ -12,6 +12,34 @@ else()
   set(cmake_3_2_USES_TERMINAL USES_TERMINAL)
 endif()
 
+function(get_effective_platform_for_triple triple output)
+  string(FIND "${triple}" "macos" IS_MACOS)
+  if (IS_MACOS)
+    set(${output} "" PARENT_SCOPE)
+    return()
+  endif()
+  message(FATAL_ERROR "Not supported")
+endfunction()
+
+# Eliminate $(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME) from a path.
+#
+# We do not support compiling llvm with an Xcode setting beyond the one that was
+# used with build-script. This allows us to remove those paths. Right now,
+# nothing here is tested for cross compiling with Xcode, but it is in principal
+# possible.
+function(escape_llvm_path_for_xcode path outvar)
+  # First check if we are using Xcode. If not, return early.
+  if (NOT XCODE)
+    set(${outvar} "${path}" PARENT_SCOPE)
+    return()
+  endif()
+
+  get_effective_platform_for_triple("${SWIFT_HOST_TRIPLE}" SWIFT_EFFECTIVE_PLATFORM_NAME)
+  string(REPLACE "$(CONFIGURATION)" "${LLVM_BUILD_TYPE}" path "${path}")
+  string(REPLACE "$(EFFECTIVE_PLATFORM_NAME)" "${SWIFT_EFFECTIVE_PLATFORM_NAME}" path "${path}")
+  set(${outvar} "${path}" PARENT_SCOPE)
+endfunction()
+
 macro(swift_common_standalone_build_config_llvm product is_cross_compiling)
   option(LLVM_ENABLE_WARNINGS "Enable compiler warnings." ON)
 
@@ -55,20 +83,23 @@ macro(swift_common_standalone_build_config_llvm product is_cross_compiling)
   mark_as_advanced(LLVM_ENABLE_ASSERTIONS)
 
   precondition(LLVM_TOOLS_BINARY_DIR)
+  escape_llvm_path_for_xcode("${LLVM_TOOLS_BINARY_DIR}" LLVM_TOOLS_BINARY_DIR)
   precondition_translate_flag(LLVM_BUILD_LIBRARY_DIR LLVM_LIBRARY_DIR)
+  escape_llvm_path_for_xcode("${LLVM_LIBRARY_DIR}" LLVM_LIBRARY_DIR)
   precondition_translate_flag(LLVM_BUILD_MAIN_INCLUDE_DIR LLVM_MAIN_INCLUDE_DIR)
   precondition_translate_flag(LLVM_BUILD_BINARY_DIR LLVM_BINARY_DIR)
   precondition_translate_flag(LLVM_BUILD_MAIN_SRC_DIR LLVM_MAIN_SRC_DIR)
+  precondition(LLVM_LIBRARY_DIRS)
+  escape_llvm_path_for_xcode("${LLVM_LIBRARY_DIRS}" LLVM_LIBRARY_DIRS)
 
-  if(${is_cross_compiling})
-    find_program(SWIFT_TABLEGEN_EXE "llvm-tblgen" "${${product}_NATIVE_LLVM_TOOLS_PATH}"
-      NO_DEFAULT_PATH)
-    if ("${SWIFT_TABLEGEN_EXE}" STREQUAL "SWIFT_TABLEGEN_EXE-NOTFOUND")
-      message(FATAL_ERROR "Failed to find tablegen in ${${product}_NATIVE_LLVM_TOOLS_PATH}")
-    endif()
-  else()
-    set(SWIFT_TABLEGEN_EXE llvm-tblgen)
-    set(${product}_NATIVE_LLVM_TOOLS_PATH "${PATH_TO_LLVM_TOOLS_BINARY_DIR}")
+  if(NOT ${is_cross_compiling})
+    set(${product}_NATIVE_LLVM_TOOLS_PATH "${LLVM_TOOLS_BINARY_DIR}")
+  endif()
+
+  find_program(SWIFT_TABLEGEN_EXE "llvm-tblgen" "${${product}_NATIVE_LLVM_TOOLS_PATH}"
+    NO_DEFAULT_PATH)
+  if ("${SWIFT_TABLEGEN_EXE}" STREQUAL "SWIFT_TABLEGEN_EXE-NOTFOUND")
+    message(FATAL_ERROR "Failed to find tablegen in ${${product}_NATIVE_LLVM_TOOLS_PATH}")
   endif()
 
   include(AddLLVM)
@@ -86,6 +117,7 @@ macro(swift_common_standalone_build_config_llvm product is_cross_compiling)
     "Version number that will be placed into the libclang library , in the form XX.YY")
 
   foreach (INCLUDE_DIR ${LLVM_INCLUDE_DIRS})
+    escape_llvm_path_for_xcode("${INCLUDE_DIR}" INCLUDE_DIR)
     include_directories(${INCLUDE_DIR})
   endforeach ()
 
@@ -144,7 +176,7 @@ macro(swift_common_standalone_build_config_clang product is_cross_compiling)
   set(CLANG_BUILD_INCLUDE_DIR "${PATH_TO_CLANG_BUILD}/tools/clang/include")
 
   if (NOT ${is_cross_compiling})
-    set(${product}_NATIVE_CLANG_TOOLS_PATH "${PATH_TO_LLVM_TOOLS_BINARY_DIR}")
+    set(${product}_NATIVE_CLANG_TOOLS_PATH "${LLVM_TOOLS_BINARY_DIR}")
   endif()
 
   set(CLANG_MAIN_INCLUDE_DIR "${CLANG_MAIN_SRC_DIR}/include")