[GOFF] Introduce GOFFWriter class (llvm#131216)

The GOFFWriter has 2 purposes:
- Simplify resource management
- Enable writing of split DWARF files

It follows the design of the other writer classes. No added
functionality at this point.

This changes also makes the GOFFObjectWriter a public class.

Author: redstar

llvm/include/llvm/MC/MCGOFFObjectWriter.h

@@ -10,6 +10,7 @@
 #define LLVM_MC_MCGOFFOBJECTWRITER_H
 
 #include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCValue.h"
 
 namespace llvm {
 class MCObjectWriter;
@@ -29,6 +30,25 @@ class MCGOFFObjectTargetWriter : public MCObjectTargetWriter {
   }
 };
 
+class GOFFObjectWriter : public MCObjectWriter {
+  // The target specific GOFF writer instance.
+  std::unique_ptr<MCGOFFObjectTargetWriter> TargetObjectWriter;
+
+  // The stream used to write the GOFF records.
+  raw_pwrite_stream &OS;
+
+public:
+  GOFFObjectWriter(std::unique_ptr<MCGOFFObjectTargetWriter> MOTW,
+                   raw_pwrite_stream &OS);
+  ~GOFFObjectWriter() override;
+
+  // Implementation of the MCObjectWriter interface.
+  void recordRelocation(const MCFragment &F, const MCFixup &Fixup,
+                        MCValue Target, uint64_t &FixedValue) override {}
+
+  uint64_t writeObject() override;
+};
+
 /// \brief Construct a new GOFF writer instance.
 ///
 /// \param MOTW - The target-specific GOFF writer subclass.

llvm/include/llvm/MC/MCGOFFStreamer.h

@@ -13,6 +13,7 @@
 #include "llvm/MC/MCObjectWriter.h"
 
 namespace llvm {
+class GOFFObjectWriter;
 
 class MCGOFFStreamer : public MCObjectStreamer {
 public:
@@ -24,6 +25,8 @@ class MCGOFFStreamer : public MCObjectStreamer {
 
   ~MCGOFFStreamer() override;
 
+  GOFFObjectWriter &getWriter();
+
   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
     return false;
   }

llvm/lib/MC/GOFFObjectWriter.cpp

@@ -223,33 +223,21 @@ void GOFFOstream::finalizeRecord() {
 }
 
 namespace {
-
-class GOFFObjectWriter : public MCObjectWriter {
-  // The target specific GOFF writer instance.
-  std::unique_ptr<MCGOFFObjectTargetWriter> TargetObjectWriter;
-
-  // The stream used to write the GOFF records.
+class GOFFWriter {
   GOFFOstream OS;
 
-public:
-  GOFFObjectWriter(std::unique_ptr<MCGOFFObjectTargetWriter> MOTW,
-                   raw_pwrite_stream &OS)
-      : TargetObjectWriter(std::move(MOTW)), OS(OS) {}
-
-  ~GOFFObjectWriter() override {}
-
-  // Write GOFF records.
   void writeHeader();
   void writeEnd();
 
-  // Implementation of the MCObjectWriter interface.
-  void recordRelocation(const MCFragment &F, const MCFixup &Fixup,
-                        MCValue Target, uint64_t &FixedValue) override {}
-  uint64_t writeObject() override;
+public:
+  GOFFWriter(raw_pwrite_stream &OS);
+  uint64_t writeObject();
 };
-} // end anonymous namespace
+} // namespace
 
-void GOFFObjectWriter::writeHeader() {
+GOFFWriter::GOFFWriter(raw_pwrite_stream &OS) : OS(OS) {}
+
+void GOFFWriter::writeHeader() {
   OS.newRecord(GOFF::RT_HDR);
   OS.write_zeros(1);       // Reserved
   OS.writebe<uint32_t>(0); // Target Hardware Environment
@@ -263,7 +251,7 @@ void GOFFObjectWriter::writeHeader() {
   OS.write_zeros(6);       // Reserved
 }
 
-void GOFFObjectWriter::writeEnd() {
+void GOFFWriter::writeEnd() {
   uint8_t F = GOFF::END_EPR_None;
   uint8_t AMODE = 0;
   uint32_t ESDID = 0;
@@ -281,7 +269,7 @@ void GOFFObjectWriter::writeEnd() {
   OS.writebe<uint32_t>(ESDID); // ESDID (of entry point)
 }
 
-uint64_t GOFFObjectWriter::writeObject() {
+uint64_t GOFFWriter::writeObject() {
   writeHeader();
   writeEnd();
 
@@ -294,6 +282,17 @@ uint64_t GOFFObjectWriter::writeObject() {
   return OS.getWrittenSize();
 }
 
+GOFFObjectWriter::GOFFObjectWriter(
+    std::unique_ptr<MCGOFFObjectTargetWriter> MOTW, raw_pwrite_stream &OS)
+    : TargetObjectWriter(std::move(MOTW)), OS(OS) {}
+
+GOFFObjectWriter::~GOFFObjectWriter() {}
+
+uint64_t GOFFObjectWriter::writeObject() {
+  uint64_t Size = GOFFWriter(OS).writeObject();
+  return Size;
+}
+
 std::unique_ptr<MCObjectWriter>
 llvm::createGOFFObjectWriter(std::unique_ptr<MCGOFFObjectTargetWriter> MOTW,
                              raw_pwrite_stream &OS) {

llvm/lib/MC/MCGOFFStreamer.cpp

@@ -15,12 +15,17 @@
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCGOFFObjectWriter.h"
 #include "llvm/MC/TargetRegistry.h"
 
 using namespace llvm;
 
 MCGOFFStreamer::~MCGOFFStreamer() {}
 
+GOFFObjectWriter &MCGOFFStreamer::getWriter() {
+  return static_cast<GOFFObjectWriter &>(getAssembler().getWriter());
+}
+
 MCStreamer *llvm::createGOFFStreamer(MCContext &Context,
                                      std::unique_ptr<MCAsmBackend> &&MAB,
                                      std::unique_ptr<MCObjectWriter> &&OW,