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

12 files changed, 104 insertions, 51 deletions

diff --git a/include/llvm/MC/MCELFStreamer.h b/include/llvm/MC/MCELFStreamer.h
index 60a360f896..0413613232 100644
--- a/include/llvm/MC/MCELFStreamer.h
+++ b/include/llvm/MC/MCELFStreamer.h
@@ -28,15 +28,20 @@ class MCSymbolData;
 class raw_ostream;
 
 class MCELFStreamer : public MCObjectStreamer {
-public:
-  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+protected:
+  MCELFStreamer(StreamerKind Kind, MCContext &Context, MCAsmBackend &TAB,
                 raw_ostream &OS, MCCodeEmitter *Emitter)
-    : MCObjectStreamer(Context, TAB, OS, Emitter) {}
+      : MCObjectStreamer(Kind, Context, TAB, OS, Emitter) {}
+
+public:
+  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
+                MCCodeEmitter *Emitter)
+      : MCObjectStreamer(SK_ELFStreamer, Context, TAB, OS, Emitter) {}
 
-  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
-                raw_ostream &OS, MCCodeEmitter *Emitter,
-                MCAssembler *Assembler)
-    : MCObjectStreamer(Context, TAB, OS, Emitter, Assembler) {}
+  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
+                MCCodeEmitter *Emitter, MCAssembler *Assembler)
+      : MCObjectStreamer(SK_ELFStreamer, Context, TAB, OS, Emitter,
+                         Assembler) {}
 
   virtual ~MCELFStreamer();
 
@@ -81,6 +86,10 @@ public:
   virtual void FinishImpl();
   /// @}
 
+  static bool classof(const MCStreamer *S) {
+    return S->getKind() == SK_ELFStreamer && S->getKind() == SK_ARMELFStreamer;
+  }
+
 private:
   virtual void EmitInstToFragment(const MCInst &Inst);
   virtual void EmitInstToData(const MCInst &Inst);
diff --git a/include/llvm/MC/MCObjectStreamer.h b/include/llvm/MC/MCObjectStreamer.h
index d73fe3abd0..f06c49ff08 100644
--- a/include/llvm/MC/MCObjectStreamer.h
+++ b/include/llvm/MC/MCObjectStreamer.h
@@ -38,9 +38,9 @@ class MCObjectStreamer : public MCStreamer {
   virtual void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame);
 
 protected:
-  MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
+  MCObjectStreamer(StreamerKind Kind, MCContext &Context, MCAsmBackend &TAB,
                    raw_ostream &_OS, MCCodeEmitter *_Emitter);
-  MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
+  MCObjectStreamer(StreamerKind Kind, MCContext &Context, MCAsmBackend &TAB,
                    raw_ostream &_OS, MCCodeEmitter *_Emitter,
                    MCAssembler *_Assembler);
   ~MCObjectStreamer();
@@ -107,6 +107,10 @@ public:
   virtual void FinishImpl();
 
   /// @}
+
+  static bool classof(const MCStreamer *S) {
+    return S->getKind() >= SK_ELFStreamer && S->getKind() <= SK_WinCOFFStreamer;
+  }
 };
 
 } // end namespace llvm
diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h
index c6246e102f..36313258c7 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();
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 71919473a3..71be1a9b89 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -71,7 +71,7 @@ public:
                 MCInstPrinter *printer, MCCodeEmitter *emitter,
                 MCAsmBackend *asmbackend,
                 bool showInst)
-    : MCStreamer(Context), OS(os), MAI(Context.getAsmInfo()),
+    : MCStreamer(SK_AsmStreamer, Context), OS(os), MAI(Context.getAsmInfo()),
       InstPrinter(printer), Emitter(emitter), AsmBackend(asmbackend),
       CommentStream(CommentToEmit), IsVerboseAsm(isVerboseAsm),
       ShowInst(showInst), UseLoc(useLoc), UseCFI(useCFI),
@@ -277,6 +277,10 @@ public:
   virtual void FinishImpl();
 
   /// @}
+
+  static bool classof(const MCStreamer *S) {
+    return S->getKind() == SK_NullStreamer;
+  }
 };
 
 } // end anonymous namespace.
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 2c0c97af47..7d08d0ecd5 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -34,9 +34,9 @@ private:
   void EmitDataRegion(DataRegionData::KindTy Kind);
   void EmitDataRegionEnd();
 public:
-  MCMachOStreamer(MCContext &Context, MCAsmBackend &MAB,
-                  raw_ostream &OS, MCCodeEmitter *Emitter)
-    : MCObjectStreamer(Context, MAB, OS, Emitter) {}
+  MCMachOStreamer(MCContext &Context, MCAsmBackend &MAB, raw_ostream &OS,
+                  MCCodeEmitter *Emitter)
+      : MCObjectStreamer(SK_MachOStreamer, Context, MAB, OS, Emitter) {}
 
   /// @name MCStreamer Interface
   /// @{
@@ -87,6 +87,10 @@ public:
   virtual void FinishImpl();
 
   /// @}
+
+  static bool classof(const MCStreamer *S) {
+    return S->getKind() == SK_MachOStreamer;
+  }
 };
 
 } // end anonymous namespace.
diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp
index 3eee5caf6f..89f74c1709 100644
--- a/lib/MC/MCNullStreamer.cpp
+++ b/lib/MC/MCNullStreamer.cpp
@@ -19,7 +19,7 @@ namespace {
 
   class MCNullStreamer : public MCStreamer {
   public:
-    MCNullStreamer(MCContext &Context) : MCStreamer(Context) {}
+    MCNullStreamer(MCContext &Context) : MCStreamer(SK_NullStreamer, Context) {}
 
     /// @name MCStreamer Interface
     /// @{
@@ -109,6 +109,11 @@ namespace {
     }
 
     /// @}
+
+    static bool classof(const MCStreamer *S) {
+      return S->getKind() == SK_NullStreamer;
+    }
+
   };
 
 }
diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp
index 6f2dce6c87..5aa4b40a6d 100644
--- a/lib/MC/MCObjectStreamer.cpp
+++ b/lib/MC/MCObjectStreamer.cpp
@@ -20,22 +20,19 @@
 #include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
-MCObjectStreamer::MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
-                                   raw_ostream &OS, MCCodeEmitter *Emitter_)
-  : MCStreamer(Context),
-    Assembler(new MCAssembler(Context, TAB,
-                              *Emitter_, *TAB.createObjectWriter(OS),
-                              OS)),
-    CurSectionData(0)
-{
-}
-
-MCObjectStreamer::MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
-                                   raw_ostream &OS, MCCodeEmitter *Emitter_,
+MCObjectStreamer::MCObjectStreamer(StreamerKind Kind, MCContext &Context,
+                                   MCAsmBackend &TAB, raw_ostream &OS,
+                                   MCCodeEmitter *Emitter_)
+    : MCStreamer(Kind, Context),
+      Assembler(new MCAssembler(Context, TAB, *Emitter_,
+                                *TAB.createObjectWriter(OS), OS)),
+      CurSectionData(0) {}
+
+MCObjectStreamer::MCObjectStreamer(StreamerKind Kind, MCContext &Context,
+                                   MCAsmBackend &TAB, raw_ostream &OS,
+                                   MCCodeEmitter *Emitter_,
                                    MCAssembler *_Assembler)
-  : MCStreamer(Context), Assembler(_Assembler), CurSectionData(0)
-{
-}
+    : MCStreamer(Kind, Context), Assembler(_Assembler), CurSectionData(0) {}
 
 MCObjectStreamer::~MCObjectStreamer() {
   delete &Assembler->getBackend();
diff --git a/lib/MC/MCPureStreamer.cpp b/lib/MC/MCPureStreamer.cpp
index 6ce7ae81d5..573308abb8 100644
--- a/lib/MC/MCPureStreamer.cpp
+++ b/lib/MC/MCPureStreamer.cpp
@@ -28,9 +28,9 @@ private:
   virtual void EmitInstToData(const MCInst &Inst);
 
 public:
-  MCPureStreamer(MCContext &Context, MCAsmBackend &TAB,
-                 raw_ostream &OS, MCCodeEmitter *Emitter)
-    : MCObjectStreamer(Context, TAB, OS, Emitter) {}
+  MCPureStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
+                 MCCodeEmitter *Emitter)
+      : MCObjectStreamer(SK_PureStreamer, Context, TAB, OS, Emitter) {}
 
   /// @name MCStreamer Interface
   /// @{
@@ -100,6 +100,10 @@ public:
   }
 
   /// @}
+
+  static bool classof(const MCStreamer *S) {
+    return S->getKind() == SK_PureStreamer;
+  }
 };
 
 } // end anonymous namespace.
diff --git a/lib/MC/MCStreamer.cpp b/lib/MC/MCStreamer.cpp
index 00ebde3c40..e92569b0cc 100644
--- a/lib/MC/MCStreamer.cpp
+++ b/lib/MC/MCStreamer.cpp
@@ -21,10 +21,9 @@
 #include <cstdlib>
 using namespace llvm;
 
-MCStreamer::MCStreamer(MCContext &Ctx)
-  : Context(Ctx), EmitEHFrame(true), EmitDebugFrame(false),
-    CurrentW64UnwindInfo(0), LastSymbol(0),
-    AutoInitSections(false) {
+MCStreamer::MCStreamer(StreamerKind Kind, MCContext &Ctx)
+    : Kind(Kind), Context(Ctx), EmitEHFrame(true), EmitDebugFrame(false),
+      CurrentW64UnwindInfo(0), LastSymbol(0), AutoInitSections(false) {
   const MCSection *section = NULL;
   SectionStack.push_back(std::make_pair(section, section));
 }
diff --git a/lib/MC/WinCOFFStreamer.cpp b/lib/MC/WinCOFFStreamer.cpp
index b529489b1a..75f343c421 100644
--- a/lib/MC/WinCOFFStreamer.cpp
+++ b/lib/MC/WinCOFFStreamer.cpp
@@ -75,6 +75,10 @@ public:
   virtual void EmitWin64EHHandlerData();
   virtual void FinishImpl();
 
+  static bool classof(const MCStreamer *S) {
+    return S->getKind() == SK_WinCOFFStreamer;
+  }
+
 private:
   virtual void EmitInstToData(const MCInst &Inst) {
     MCDataFragment *DF = getOrCreateDataFragment();
@@ -128,13 +132,10 @@ private:
 };
 } // end anonymous namespace.
 
-WinCOFFStreamer::WinCOFFStreamer(MCContext &Context,
-                                 MCAsmBackend &MAB,
-                                 MCCodeEmitter &CE,
-                                 raw_ostream &OS)
-    : MCObjectStreamer(Context, MAB, OS, &CE)
-    , CurSymbol(NULL) {
-}
+WinCOFFStreamer::WinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
+                                 MCCodeEmitter &CE, raw_ostream &OS)
+    : MCObjectStreamer(SK_WinCOFFStreamer, Context, MAB, OS, &CE),
+      CurSymbol(NULL) {}
 
 void WinCOFFStreamer::AddCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                       unsigned ByteAlignment, bool External) {
diff --git a/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp b/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
index 526f5712a0..418971df32 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
@@ -54,12 +54,11 @@ namespace {
 /// by MachO. Beware!
 class ARMELFStreamer : public MCELFStreamer {
 public:
-  ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
-                 raw_ostream &OS, MCCodeEmitter *Emitter, bool IsThumb)
-    : MCELFStreamer(Context, TAB, OS, Emitter),
-      IsThumb(IsThumb), MappingSymbolCounter(0), LastEMS(EMS_None),
-      ExTab(0), FnStart(0), Personality(0), CantUnwind(false) {
-  }
+  ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
+                 MCCodeEmitter *Emitter, bool IsThumb)
+      : MCELFStreamer(SK_ARMELFStreamer, Context, TAB, OS, Emitter),
+        IsThumb(IsThumb), MappingSymbolCounter(0), LastEMS(EMS_None), ExTab(0),
+        FnStart(0), Personality(0), CantUnwind(false) {}
 
   ~ARMELFStreamer() {}
 
@@ -134,6 +133,10 @@ public:
     }
   }
 
+  static bool classof(const MCStreamer *S) {
+    return S->getKind() == SK_ARMELFStreamer;
+  }
+
 private:
   enum ElfMappingSymbol {
     EMS_None,
diff --git a/tools/lto/LTOModule.cpp b/tools/lto/LTOModule.cpp
index d90a403cf9..e2bf858326 100644
--- a/tools/lto/LTOModule.cpp
+++ b/tools/lto/LTOModule.cpp
@@ -733,7 +733,8 @@ namespace {
       return Symbols.end();
     }
 
-    RecordStreamer(MCContext &Context) : MCStreamer(Context) {}
+    RecordStreamer(MCContext &Context)
+        : MCStreamer(SK_RecordStreamer, Context) {}
 
     virtual void EmitInstruction(const MCInst &Inst) {
       // Scan for values.
@@ -804,6 +805,10 @@ namespace {
                                           const MCSymbol *Label,
                                           unsigned PointerSize) {}
     virtual void FinishImpl() {}
+
+    static bool classof(const MCStreamer *S) {
+      return S->getKind == SK_RecordStreamer;
+    }
   };
 } // end anonymous namespace