[ms] [llvm-ml] Enable support for MASM-style macro procedures

Allows the MACRO directive to define macro procedures with parameters and macro-local symbols.

Supports required and optional parameters (including default values), and matches ml64.exe for its macro-local symbol handling (up to 65536 macro-local symbols in any translation unit).

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D89729

Author: ericastor

llvm/include/llvm/MC/MCAsmMacro.h

@@ -143,10 +143,14 @@ struct MCAsmMacro {
   StringRef Name;
   StringRef Body;
   MCAsmMacroParameters Parameters;
+  std::vector<std::string> Locals;
 
 public:
   MCAsmMacro(StringRef N, StringRef B, MCAsmMacroParameters P)
       : Name(N), Body(B), Parameters(std::move(P)) {}
+  MCAsmMacro(StringRef N, StringRef B, MCAsmMacroParameters P,
+             std::vector<std::string> L)
+      : Name(N), Body(B), Parameters(std::move(P)), Locals(std::move(L)) {}
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
   void dump() const { dump(dbgs()); }

llvm/lib/MC/MCAsmMacro.cpp

@@ -38,6 +38,11 @@ void MCAsmMacro::dump(raw_ostream &OS) const {
     OS << "    ";
     P.dump();
   }
+  if (!Locals.empty()) {
+    OS << "  Locals:\n";
+    for (StringRef L : Locals)
+      OS << "    " << L << '\n';
+  }
   OS << "  (BEGIN BODY)" << Body << "(END BODY)\n";
 }
 #endif