[Clang][TableGen] Add explicit symbol visibility macros to code gener…

…ated

Update ClangAttrEmitter tablegen to add explicit symbol visibility macros
to function declarations it creates.
Both AnnotateFunctions and Attribute example plugins require clang::AnnotateAttr
TableGen created functions to be exported from the Clang shared library.

clang/utils/TableGen/ClangAttrEmitter.cpp

@@ -2762,7 +2762,7 @@ static void emitAttributes(const RecordKeeper &Records, raw_ostream &OS,
     }
 
     if (Header)
-      OS << "class " << R.getName() << "Attr : public " << SuperName << " {\n";
+      OS << "class CLANG_ABI " << R.getName() << "Attr : public " << SuperName << " {\n";
     else
       OS << "\n// " << R.getName() << "Attr implementation\n\n";
 
@@ -3220,7 +3220,8 @@ void clang::EmitClangAttrClass(const RecordKeeper &Records, raw_ostream &OS) {
   emitSourceFileHeader("Attribute classes' definitions", OS, Records);
 
   OS << "#ifndef LLVM_CLANG_ATTR_CLASSES_INC\n";
-  OS << "#define LLVM_CLANG_ATTR_CLASSES_INC\n\n";
+  OS << "#define LLVM_CLANG_ATTR_CLASSES_INC\n";
+  OS << "#include \"clang/Support/Compiler.h\"\n\n";
 
   emitAttributes(Records, OS, true);