[CMake] NFC. Add clang-tablegen-targets utility target

By creating this target other projects that depend on clang-generated headers (like LLDB) will no longer be order-dependent on Clang being processed by CMake first.

Also, by creating a dummy of this target in ClangConfig.cmake, projects that can build against out-of-tree clang can freely depend on the target without needing to have conditionals for if clang is in-tree or out-of-tree.

llvm-svn: 309390

diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
index 5d303ee..8f26f2d 100644 (file)
--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@@ -412,7 +412,8 @@ add_subdirectory(include)
 
 # All targets below may depend on all tablegen'd files.
 get_property(CLANG_TABLEGEN_TARGETS GLOBAL PROPERTY CLANG_TABLEGEN_TARGETS)
-list(APPEND LLVM_COMMON_DEPENDS ${CLANG_TABLEGEN_TARGETS})
+add_custom_target(clang-tablegen-targets DEPENDS ${CLANG_TABLEGEN_TARGETS})
+list(APPEND LLVM_COMMON_DEPENDS clang-tablegen-targets)
 
 # Force target to be built as soon as possible. Clang modules builds depend
 # header-wise on it as they ship all headers from the umbrella folders. Building

diff --git a/clang/cmake/modules/ClangConfig.cmake.in b/clang/cmake/modules/ClangConfig.cmake.in
index 03bca69..a5a7eae 100644 (file)
--- a/clang/cmake/modules/ClangConfig.cmake.in
+++ b/clang/cmake/modules/ClangConfig.cmake.in
@@ -11,3 +11,10 @@ set(CLANG_INCLUDE_DIRS "@CLANG_CONFIG_INCLUDE_DIRS@")
 
 # Provide all our library targets to users.
 include("@CLANG_CONFIG_EXPORTS_FILE@")
+
+# By creating clang-tablegen-targets here, subprojects that depend on Clang's
+# tablegen-generated headers can always depend on this target whether building
+# in-tree with Clang or not.
+if(NOT TARGET clang-tablegen-targets)
+  add_custom_target(clang-tablegen-targets)
+endif()