Add a MCTargetStreamer interface.

This patch fixes an old FIXME by creating a MCTargetStreamer interface
and moving the target specific functions for ARM, Mips and PPC to it.

The ARM streamer is still declared in a common place because it is
used from lib/CodeGen/ARMException.cpp, but the Mips and PPC are
completely hidden in the corresponding Target directories.

I will send an email to llvmdev with instructions on how to use this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192181 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 98 insertions, 53 deletions

diff --git a/include/llvm/MC/MCELFStreamer.h b/include/llvm/MC/MCELFStreamer.h
index 0f45a93f95..8dbe337b0f 100644
--- a/include/llvm/MC/MCELFStreamer.h
+++ b/include/llvm/MC/MCELFStreamer.h
@@ -29,13 +29,15 @@ class raw_ostream;
 
 class MCELFStreamer : public MCObjectStreamer {
 public:
-  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
-                MCCodeEmitter *Emitter)
-      : MCObjectStreamer(Context, TAB, OS, Emitter) {}
+  MCELFStreamer(MCContext &Context, MCTargetStreamer *TargetStreamer,
+                MCAsmBackend &TAB, raw_ostream &OS, MCCodeEmitter *Emitter)
+      : MCObjectStreamer(Context, TargetStreamer, TAB, OS, Emitter) {}
 
-  MCELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
-                MCCodeEmitter *Emitter, MCAssembler *Assembler)
-      : MCObjectStreamer(Context, TAB, OS, Emitter, Assembler) {}
+  MCELFStreamer(MCContext &Context, MCTargetStreamer *TargetStreamer,
+                MCAsmBackend &TAB, raw_ostream &OS, MCCodeEmitter *Emitter,
+                MCAssembler *Assembler)
+      : MCObjectStreamer(Context, TargetStreamer, TAB, OS, Emitter, Assembler) {
+  }
 
   virtual ~MCELFStreamer();
 
@@ -75,8 +77,6 @@ public:
 
   virtual void EmitFileDirective(StringRef Filename);
 
-  virtual void EmitTCEntry(const MCSymbol &S);
-
   virtual void EmitValueToAlignment(unsigned, int64_t, unsigned, unsigned);
 
   virtual void Flush();
@@ -111,10 +111,6 @@ private:
   void SetSectionBss();
 };
 
-MCELFStreamer *createMipsELFStreamer(MCContext &Context, MCAsmBackend &TAB,
-                                     raw_ostream &OS, MCCodeEmitter *Emitter,
-                                     bool RelaxAll, bool NoExecStack);
-
 MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
                                     raw_ostream &OS, MCCodeEmitter *Emitter,
                                     bool RelaxAll, bool NoExecStack,
diff --git a/include/llvm/MC/MCObjectStreamer.h b/include/llvm/MC/MCObjectStreamer.h
index f6a7e713c4..5667544301 100644
--- a/include/llvm/MC/MCObjectStreamer.h
+++ b/include/llvm/MC/MCObjectStreamer.h
@@ -40,10 +40,12 @@ class MCObjectStreamer : public MCStreamer {
   virtual void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame);
 
 protected:
-  MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &_OS,
+  MCObjectStreamer(MCContext &Context, MCTargetStreamer *TargetStreamer,
+                   MCAsmBackend &TAB, raw_ostream &_OS,
                    MCCodeEmitter *_Emitter);
-  MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &_OS,
-                   MCCodeEmitter *_Emitter, MCAssembler *_Assembler);
+  MCObjectStreamer(MCContext &Context, MCTargetStreamer *TargetStreamer,
+                   MCAsmBackend &TAB, raw_ostream &_OS, MCCodeEmitter *_Emitter,
+                   MCAssembler *_Assembler);
   ~MCObjectStreamer();
 
 public:
diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h
index 3cd5c773c1..10fc69ef84 100644
--- a/include/llvm/MC/MCStreamer.h
+++ b/include/llvm/MC/MCStreamer.h
@@ -31,6 +31,7 @@ class MCExpr;
 class MCInst;
 class MCInstPrinter;
 class MCSection;
+class MCStreamer;
 class MCSymbol;
 class StringRef;
 class Twine;
@@ -39,6 +40,55 @@ class formatted_raw_ostream;
 
 typedef std::pair<const MCSection *, const MCExpr *> MCSectionSubPair;
 
+/// Target specific streamer interface. This is used so that targets can
+/// implement support for target specific assembly directives.
+///
+/// If target foo wants to use this, it should implement 3 classes:
+/// * FooTargetStreamer : public MCTargetStreamer
+/// * FooTargetAsmSreamer : public FooTargetStreamer
+/// * FooTargetELFStreamer : public FooTargetStreamer
+///
+/// FooTargetStreamer should have a pure virtual method for each directive. For
+/// example, for a ".bar symbol_name" directive, it should have
+/// virtual emitBar(const MCSymbol &Symbol) = 0;
+///
+/// The FooTargetAsmSreamer and FooTargetELFStreamer classes implement the
+/// method. The assembly streamer just prints ".bar symbol_name". The object
+/// streamer does whatever is needed to implement .bar in the object file.
+///
+/// In the assembly printer and parser the target streamer can be used by
+/// calling getTargetStreamer and casting it to FooTargetStreamer:
+///
+/// MCTargetStreamer &TS = OutStreamer.getTargetStreamer();
+/// FooTargetStreamer &ATS = static_cast<FooTargetStreamer &>(TS);
+///
+/// The base classes FooTargetAsmSreamer and FooTargetELFStreamer should *never*
+/// be treated differently. Callers should always talk to a FooTargetStreamer.
+class MCTargetStreamer {
+protected:
+  OwningPtr<MCStreamer> Streamer;
+
+public:
+  virtual ~MCTargetStreamer();
+  void setStreamer(MCStreamer *S) { Streamer.reset(S); }
+};
+
+// FIXME: declared here because it is used from
+// lib/CodeGen/AsmPrinter/ARMException.cpp.
+class ARMTargetStreamer : public MCTargetStreamer {
+public:
+  virtual void emitFnStart() = 0;
+  virtual void emitFnEnd() = 0;
+  virtual void emitCantUnwind() = 0;
+  virtual void emitPersonality(const MCSymbol *Personality) = 0;
+  virtual void emitHandlerData() = 0;
+  virtual void emitSetFP(unsigned FpReg, unsigned SpReg,
+                         int64_t Offset = 0) = 0;
+  virtual void emitPad(int64_t Offset) = 0;
+  virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
+                           bool isVector) = 0;
+};
+
 /// MCStreamer - Streaming machine code generation interface.  This interface
 /// is intended to provide a programatic interface that is very similar to the
 /// level that an assembler .s file provides.  It has callbacks to emit bytes,
@@ -50,6 +100,7 @@ typedef std::pair<const MCSection *, const MCExpr *> MCSectionSubPair;
 ///
 class MCStreamer {
   MCContext &Context;
+  MCTargetStreamer *TargetStreamer;
 
   MCStreamer(const MCStreamer &) LLVM_DELETED_FUNCTION;
   MCStreamer &operator=(const MCStreamer &) LLVM_DELETED_FUNCTION;
@@ -80,7 +131,7 @@ class MCStreamer {
   bool AutoInitSections;
 
 protected:
-  MCStreamer(MCContext &Ctx);
+  MCStreamer(MCContext &Ctx, MCTargetStreamer *TargetStreamer);
 
   const MCExpr *BuildSymbolDiff(MCContext &Context, const MCSymbol *A,
                                 const MCSymbol *B);
@@ -107,6 +158,11 @@ public:
 
   MCContext &getContext() const { return Context; }
 
+  MCTargetStreamer &getTargetStreamer() {
+    assert(TargetStreamer);
+    return *TargetStreamer;
+  }
+
   unsigned getNumFrameInfos() { return FrameInfos.size(); }
 
   const MCDwarfFrameInfo &getFrameInfo(unsigned i) { return FrameInfos[i]; }
@@ -600,28 +656,6 @@ public:
   virtual void EmitRawText(StringRef String);
   void EmitRawText(const Twine &String);
 
-  /// ARM-related methods.
-  /// FIXME: Eventually we should have some "target MC streamer" and move
-  /// these methods there.
-  virtual void EmitFnStart();
-  virtual void EmitFnEnd();
-  virtual void EmitCantUnwind();
-  virtual void EmitPersonality(const MCSymbol *Personality);
-  virtual void EmitHandlerData();
-  virtual void EmitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0);
-  virtual void EmitPad(int64_t Offset);
-  virtual void EmitRegSave(const SmallVectorImpl<unsigned> &RegList,
-                           bool isVector);
-
-  /// Mips-related methods.
-  virtual void emitMipsHackELFFlags(unsigned Flags);
-  virtual void emitMipsHackSTOCG(MCSymbol *Sym, unsigned Val);
-
-  /// PPC-related methods.
-  /// FIXME: Eventually replace it with some "target MC streamer" and move
-  /// these methods there.
-  virtual void EmitTCEntry(const MCSymbol &S);
-
   /// Flush - Causes any cached state to be written out.
   virtual void Flush() {}
 
@@ -652,9 +686,9 @@ MCStreamer *createNullStreamer(MCContext &Ctx);
 ///
 /// \param ShowInst - Whether to show the MCInst representation inline with
 /// the assembly.
-MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
-                              bool isVerboseAsm, bool useLoc, bool useCFI,
-                              bool useDwarfDirectory,
+MCStreamer *createAsmStreamer(MCContext &Ctx, MCTargetStreamer *TargetStreamer,
+                              formatted_raw_ostream &OS, bool isVerboseAsm,
+                              bool useLoc, bool useCFI, bool useDwarfDirectory,
                               MCInstPrinter *InstPrint = 0,
                               MCCodeEmitter *CE = 0, MCAsmBackend *TAB = 0,
                               bool ShowInst = false);
@@ -677,8 +711,9 @@ MCStreamer *createWinCOFFStreamer(MCContext &Ctx, MCAsmBackend &TAB,
 
 /// createELFStreamer - Create a machine code streamer which will generate
 /// ELF format object files.
-MCStreamer *createELFStreamer(MCContext &Ctx, MCAsmBackend &TAB,
-                              raw_ostream &OS, MCCodeEmitter *CE, bool RelaxAll,
+MCStreamer *createELFStreamer(MCContext &Ctx, MCTargetStreamer *TargetStreamer,
+                              MCAsmBackend &TAB, raw_ostream &OS,
+                              MCCodeEmitter *CE, bool RelaxAll,
                               bool NoExecStack);
 
 /// createPureStreamer - Create a machine code streamer which will generate
diff --git a/include/llvm/Support/TargetRegistry.h b/include/llvm/Support/TargetRegistry.h
index 05f7cf2f6f..8c9a9174a9 100644
--- a/include/llvm/Support/TargetRegistry.h
+++ b/include/llvm/Support/TargetRegistry.h
@@ -46,18 +46,18 @@ namespace llvm {
   class MCRelocationInfo;
   class MCTargetAsmParser;
   class TargetMachine;
+  class MCTargetStreamer;
   class TargetOptions;
   class raw_ostream;
   class formatted_raw_ostream;
 
-  MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
-                                bool isVerboseAsm,
+  MCStreamer *createAsmStreamer(MCContext &Ctx,
+                                MCTargetStreamer *TargetStreamer,
+                                formatted_raw_ostream &OS, bool isVerboseAsm,
                                 bool useLoc, bool useCFI,
                                 bool useDwarfDirectory,
-                                MCInstPrinter *InstPrint,
-                                MCCodeEmitter *CE,
-                                MCAsmBackend *TAB,
-                                bool ShowInst);
+                                MCInstPrinter *InstPrint, MCCodeEmitter *CE,
+                                MCAsmBackend *TAB, bool ShowInst);
 
   MCRelocationInfo *createMCRelocationInfo(StringRef TT, MCContext &Ctx);
 
@@ -235,10 +235,22 @@ namespace llvm {
     /// MCSymbolizer, if registered (default = llvm::createMCSymbolizer)
     MCSymbolizerCtorTy MCSymbolizerCtorFn;
 
+    static MCStreamer *
+    createDefaultAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
+                             bool isVerboseAsm, bool useLoc, bool useCFI,
+                             bool useDwarfDirectory, MCInstPrinter *InstPrint,
+                             MCCodeEmitter *CE, MCAsmBackend *TAB,
+                             bool ShowInst) {
+      return llvm::createAsmStreamer(Ctx, 0, OS, isVerboseAsm, useLoc, useCFI,
+                                     useDwarfDirectory, InstPrint, CE, TAB,
+                                     ShowInst);
+    }
+
   public:
-    Target() : AsmStreamerCtorFn(llvm::createAsmStreamer),
-               MCRelocationInfoCtorFn(llvm::createMCRelocationInfo),
-               MCSymbolizerCtorFn(llvm::createMCSymbolizer) {}
+    Target()
+        : AsmStreamerCtorFn(createDefaultAsmStreamer),
+          MCRelocationInfoCtorFn(llvm::createMCRelocationInfo),
+          MCSymbolizerCtorFn(llvm::createMCSymbolizer) {}
 
     /// @name Target Information
     /// @{
@@ -816,7 +828,7 @@ namespace llvm {
     /// @param T - The target being registered.
     /// @param Fn - A function to construct an MCStreamer for the target.
     static void RegisterAsmStreamer(Target &T, Target::AsmStreamerCtorTy Fn) {
-      if (T.AsmStreamerCtorFn == createAsmStreamer)
+      if (T.AsmStreamerCtorFn == Target::createDefaultAsmStreamer)
         T.AsmStreamerCtorFn = Fn;
     }