Add more reset methods to make all objects that the backend may use for outputting code have a reset, some are not used but were declared for completeness

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170227 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCAsmBackend.h

@@ -41,6 +41,9 @@ protected: // Can only create subclasses.
 public:
   virtual ~MCAsmBackend();
 
+  /// lifetime management
+  virtual void reset() { }
+
   /// createObjectWriter - Create a new MCObjectWriter instance for use by the
   /// assembler backend to emit the final object file.
   virtual MCObjectWriter *createObjectWriter(raw_ostream &OS) const = 0;

include/llvm/MC/MCCodeEmitter.h

@@ -29,6 +29,9 @@ protected: // Can only create subclasses.
 public:
   virtual ~MCCodeEmitter();
 
+  /// Lifetime management
+  virtual void reset() { }
+
   /// EncodeInstruction - Encode the given \p Inst to bytes on the output
   /// stream \p OS.
   virtual void EncodeInstruction(const MCInst &Inst, raw_ostream &OS,

include/llvm/MC/MCMachObjectWriter.h

@@ -45,6 +45,13 @@ protected:
 public:
   virtual ~MCMachObjectTargetWriter();
 
+  /// @name Lifetime Management
+  /// @{
+
+  virtual void reset() {};
+
+  /// @}
+
   /// @name Accessors
   /// @{
 
@@ -111,6 +118,13 @@ public:
     : MCObjectWriter(_OS, _IsLittleEndian), TargetObjectWriter(MOTW) {
   }
 
+  /// @name Lifetime management Methods
+  /// @{
+
+  virtual void reset();
+
+  /// @}
+
   /// @name Utility Methods
   /// @{
 

include/llvm/MC/MCObjectWriter.h

@@ -51,6 +51,9 @@ protected: // Can only create subclasses.
 public:
   virtual ~MCObjectWriter();
 
+  /// lifetime management
+  virtual void reset() { }
+
   bool isLittleEndian() const { return IsLittleEndian; }
 
   raw_ostream &getStream() { return OS; }

lib/MC/MCAssembler.cpp

@@ -232,6 +232,11 @@ void MCAssembler::reset() {
   RelaxAll = false;
   NoExecStack = false;
   SubsectionsViaSymbols = false;
+
+  // reset objects owned by us
+  getBackend().reset();
+  getEmitter().reset();
+  getWriter().reset();
 }
 
 bool MCAssembler::isSymbolLinkerVisible(const MCSymbol &Symbol) const {

lib/MC/MCObjectStreamer.cpp

@@ -45,7 +45,8 @@ MCObjectStreamer::~MCObjectStreamer() {
 }
 
 void MCObjectStreamer::reset() {
-  Assembler->reset();
+  if (Assembler)
+    Assembler->reset();
   MCStreamer::reset();
 }
 

lib/MC/MachObjectWriter.cpp

@@ -27,6 +27,16 @@
 using namespace llvm;
 using namespace llvm::object;
 
+void MachObjectWriter::reset() {
+  Relocations.clear();
+  IndirectSymBase.clear();
+  StringTable.clear();
+  LocalSymbolData.clear();
+  ExternalSymbolData.clear();
+  UndefinedSymbolData.clear();
+  MCObjectWriter::reset();
+}
+
 bool MachObjectWriter::
 doesSymbolRequireExternRelocation(const MCSymbolData *SD) {
   // Undefined symbols are always extern.