[gn build] (semi-manually) Port d90443b

llvm/utils/gn/secondary/llvm/include/llvm/Frontend/OpenMP/BUILD.gn

@@ -0,0 +1,18 @@
+import("//llvm/utils/TableGen/tablegen.gni")
+
+tablegen("OMP") {
+  visibility = [ ":public_tablegen" ]
+  args = [ "-gen-directive-decls" ]
+  output_name = "OMP.h.inc"
+}
+
+# Groups all tablegen() calls that create .inc files that are included in
+# Frontent/OpenMP's public headers (just one so far).
+# //llvm/lib/Frontend/OpenMP has this as a public_dep, so targets depending on
+# //llvm/lib/Frontend/OpenMP don't need to depend on this.
+group("public_tablegen") {
+  public_deps = [
+    # Frontend/OpenMP's public headers include OMP.h.inc.
+    ":OMP",
+  ]
+}

llvm/utils/gn/secondary/llvm/lib/Frontend/OpenMP/BUILD.gn

@@ -5,6 +5,7 @@ static_library("OpenMP") {
     "//llvm/lib/Support",
     "//llvm/lib/Transforms/Utils",
   ]
+  public_deps = [ "//llvm/include/llvm/Frontend/OpenMP:public_tablegen" ]
   sources = [
     "OMPConstants.cpp",
     "OMPContext.cpp",

llvm/utils/gn/secondary/llvm/utils/TableGen/BUILD.gn

@@ -28,6 +28,7 @@ executable("llvm-tblgen") {
     "DAGISelMatcherOpt.cpp",
     "DFAEmitter.cpp",
     "DFAPacketizerEmitter.cpp",
+    "DirectiveEmitter.cpp",
     "DisassemblerEmitter.cpp",
     "ExegesisEmitter.cpp",
     "FastISelEmitter.cpp",