[MC] Export llvm::XCOFFObjectwriter and access it from MCXCOFFStreamer

Similar to commit 9539a77 for
WinCOFFObjectWriter.

Close #100412

Author: MaskRay

llvm/include/llvm/MC/MCXCOFFObjectWriter.h

@@ -39,19 +39,18 @@ class MCXCOFFObjectTargetWriter : public MCObjectTargetWriter {
   bool Is64Bit;
 };
 
+class XCOFFObjectWriter : public MCObjectWriter {
+public:
+  virtual void addExceptionEntry(const MCSymbol *Symbol, const MCSymbol *Trap,
+                                 unsigned LanguageCode, unsigned ReasonCode,
+                                 unsigned FunctionSize, bool hasDebug) = 0;
+  virtual void addCInfoSymEntry(StringRef Name, StringRef Metadata) = 0;
+};
+
 std::unique_ptr<MCObjectWriter>
 createXCOFFObjectWriter(std::unique_ptr<MCXCOFFObjectTargetWriter> MOTW,
                         raw_pwrite_stream &OS);
 
-namespace XCOFF {
-void addExceptionEntry(MCObjectWriter &Writer, const MCSymbol *Symbol,
-                       const MCSymbol *Trap, unsigned LanguageCode,
-                       unsigned ReasonCode, unsigned FunctionSize,
-                       bool hasDebug);
-void addCInfoSymEntry(MCObjectWriter &Writer, StringRef Name,
-                      StringRef Metadata);
-} // namespace XCOFF
-
 } // end namespace llvm
 
 #endif // LLVM_MC_MCXCOFFOBJECTWRITER_H

llvm/include/llvm/MC/MCXCOFFStreamer.h

@@ -12,13 +12,16 @@
 #include "llvm/MC/MCObjectStreamer.h"
 
 namespace llvm {
+class XCOFFObjectWriter;
 
 class MCXCOFFStreamer : public MCObjectStreamer {
 public:
   MCXCOFFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> MAB,
                   std::unique_ptr<MCObjectWriter> OW,
                   std::unique_ptr<MCCodeEmitter> Emitter);
 
+  XCOFFObjectWriter &getWriter();
+
   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
   void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                         Align ByteAlignment) override;

llvm/lib/MC/MCXCOFFStreamer.cpp

@@ -32,6 +32,10 @@ MCXCOFFStreamer::MCXCOFFStreamer(MCContext &Context,
     : MCObjectStreamer(Context, std::move(MAB), std::move(OW),
                        std::move(Emitter)) {}
 
+XCOFFObjectWriter &MCXCOFFStreamer::getWriter() {
+  return static_cast<XCOFFObjectWriter &>(getAssembler().getWriter());
+}
+
 bool MCXCOFFStreamer::emitSymbolAttribute(MCSymbol *Sym,
                                           MCSymbolAttr Attribute) {
   auto *Symbol = cast<MCSymbolXCOFF>(Sym);
@@ -109,14 +113,12 @@ void MCXCOFFStreamer::emitXCOFFExceptDirective(const MCSymbol *Symbol,
                                                unsigned Lang, unsigned Reason,
                                                unsigned FunctionSize,
                                                bool hasDebug) {
-  // TODO: Export XCOFFObjectWriter to llvm/MC/MCXCOFFObjectWriter.h and access
-  // it from MCXCOFFStreamer.
-  XCOFF::addExceptionEntry(getAssembler().getWriter(), Symbol, Trap, Lang,
-                           Reason, FunctionSize, hasDebug);
+  getWriter().addExceptionEntry(Symbol, Trap, Lang, Reason, FunctionSize,
+                                hasDebug);
 }
 
 void MCXCOFFStreamer::emitXCOFFCInfoSym(StringRef Name, StringRef Metadata) {
-  XCOFF::addCInfoSymEntry(getAssembler().getWriter(), Name, Metadata);
+  getWriter().addCInfoSymEntry(Name, Metadata);
 }
 
 void MCXCOFFStreamer::emitCommonSymbol(MCSymbol *Symbol, uint64_t Size,