[CMake] Module builds depend on target intrinsics_gen to be built first.

When compiling with modules, header A and B can be in the same module M.
B depends on intrinsics_gen and A doesn't. Compiling a source file #include-ing
header A, we implicitly request module M to be built. It puts header A and B in
the same TU and tries to build them. Since B depends on intrinsics_gen (which
might not be built yet) we run into build failures.

This should fix our modules buildbot.

Patch reviewed by Chris Bieneman.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274270 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/CMakeLists.txt b/CMakeLists.txt
index efa0cdfc163db82338ea045a08907ac98c7c03f6..ed3e1b8a07c115d8043c5d9f509a41b8115641af 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -700,6 +700,15 @@ add_subdirectory(lib/TableGen)
 
 add_subdirectory(utils/TableGen)
 
+# 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
+# an entire module might include header, which depends on intrinsics_gen. This
+# should be right after LLVMSupport and LLVMTableGen otherwise we introduce a
+# circular dependence.
+if (LLVM_ENABLE_MODULES)
+  list(APPEND LLVM_COMMON_DEPENDS intrinsics_gen)
+endif(LLVM_ENABLE_MODULES)
+
 add_subdirectory(include/llvm)
 
 add_subdirectory(lib)