Give the MCStreamer class hierarchy LLVM RTTI facilities for use with

isa<> and dyn_cast<>. In several places, code is already hacking around
the absence of this, and there seem to be several interfaces that might
be lifted and/or devirtualized using this.

This change was based on a discussion with Jim Grosbach about how best
to handle testing for specific MCStreamer subclasses. He said that this
was the correct end state, and everything else was too hacky so
I decided to just make it so.

No functionality should be changed here, this is just threading the kind
through all the constructors and setting up the classof overloads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174113 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 1 deletions

diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h
index c6246e1..3631325 100644
--- a/include/llvm/MC/MCStreamer.h
+++ b/include/llvm/MC/MCStreamer.h
@@ -46,6 +46,22 @@ namespace llvm {
   /// a .s file, and implementations that write out .o files of various formats.
   ///
   class MCStreamer {
+  public:
+    enum StreamerKind {
+      SK_AsmStreamer,
+      SK_NullStreamer,
+      SK_RecordStreamer,
+
+      // MCObjectStreamer subclasses.
+      SK_ELFStreamer,
+      SK_ARMELFStreamer,
+      SK_MachOStreamer,
+      SK_PureStreamer,
+      SK_WinCOFFStreamer
+    };
+
+  private:
+    const StreamerKind Kind;
     MCContext &Context;
 
     MCStreamer(const MCStreamer&) LLVM_DELETED_FUNCTION;
@@ -74,7 +90,7 @@ namespace llvm {
     bool AutoInitSections;
 
   protected:
-    MCStreamer(MCContext &Ctx);
+    MCStreamer(StreamerKind Kind, MCContext &Ctx);
 
     const MCExpr *BuildSymbolDiff(MCContext &Context, const MCSymbol *A,
                                   const MCSymbol *B);
@@ -93,6 +109,8 @@ namespace llvm {
   public:
     virtual ~MCStreamer();
 
+    StreamerKind getKind() const { return Kind; }
+
     /// State management
     ///
     virtual void reset();