[Courgette] Refactor: Add and use Instruction*Receptor classes; call ParseFile() in 2 passes.

courgette/disassembler_elf_32.h

Index: courgette/disassembler_elf_32.h
diff --git a/courgette/disassembler_elf_32.h b/courgette/disassembler_elf_32.h
index f0961c0c7ab2e9e9c9e4e7c5ee3a22e315333e39..5a99b189cabad62bc3363cd4ca85aa200251b894 100644
--- a/courgette/disassembler_elf_32.h
+++ b/courgette/disassembler_elf_32.h
@@ -21,6 +21,7 @@
 namespace courgette {
 
 class AssemblyProgram;
+class InstructionReceptor;
 
 // A Courgette disassembler for 32-bit ELF files. This is only a partial
 // implementation that admits subclasses for the architecture-specific parts of
@@ -53,8 +54,8 @@ class DisassemblerElf32 : public Disassembler {
     virtual CheckBool ComputeRelativeTarget(const uint8_t* op_pointer) = 0;
 
     // Emits the assembly instruction corresponding to |label|.
-    virtual CheckBool EmitInstruction(AssemblyProgram* program,
-                                      Label* label) = 0;
+    virtual CheckBool EmitInstruction(Label* label,
+                                      InstructionReceptor* receptor) = 0;
 
     // Returns the size of the instruction containing the RVA.
     virtual uint16_t op_size() const = 0;
@@ -163,15 +164,15 @@ class DisassemblerElf32 : public Disassembler {
   // Misc address space helpers
 
   CheckBool RVAsToFileOffsets(const std::vector<RVA>& rvas,
-                              std::vector<FileOffset>* file_offsets);
+                              std::vector<FileOffset>* file_offsets) const;
 
   CheckBool RVAsToFileOffsets(
-      std::vector<std::unique_ptr<TypedRVA>>* typed_rvas);
+      std::vector<std::unique_ptr<TypedRVA>>* typed_rvas) const;
 
   // Parsing code for Disassemble().
 
   virtual CheckBool ParseRelocationSection(const Elf32_Shdr* section_header,
-                                           AssemblyProgram* program)
+                                           InstructionReceptor* receptor) const
       WARN_UNUSED_RESULT = 0;
 
   virtual CheckBool ParseRel32RelocsFromSection(const Elf32_Shdr* section)
@@ -182,7 +183,8 @@ class DisassemblerElf32 : public Disassembler {
   RvaVisitor* CreateRel32TargetRvaVisitor() override;
   void RemoveUnusedRel32Locations(AssemblyProgram* program) override;
 
-  CheckBool ParseFile(AssemblyProgram* target) WARN_UNUSED_RESULT;
+  CheckBool ParseFile(AssemblyProgram* target,
+                      InstructionReceptor* receptor) const WARN_UNUSED_RESULT;
 
   CheckBool ParseProgbitsSection(
       const Elf32_Shdr* section_header,
@@ -190,11 +192,13 @@ class DisassemblerElf32 : public Disassembler {
       std::vector<FileOffset>::iterator end_abs_offset,
       std::vector<std::unique_ptr<TypedRVA>>::iterator* current_rel,
       std::vector<std::unique_ptr<TypedRVA>>::iterator end_rel,
-      AssemblyProgram* program) WARN_UNUSED_RESULT;
+      AssemblyProgram* program,
+      InstructionReceptor* receptor) const WARN_UNUSED_RESULT;
 
   CheckBool ParseSimpleRegion(FileOffset start_file_offset,
                               FileOffset end_file_offset,
-                              AssemblyProgram* program) WARN_UNUSED_RESULT;
+                              InstructionReceptor* receptor) const
+      WARN_UNUSED_RESULT;
 
   CheckBool ParseAbs32Relocs() WARN_UNUSED_RESULT;
 
@@ -220,8 +224,10 @@ class DisassemblerElf32 : public Disassembler {
   const char* default_string_section_;
   size_t default_string_section_size_;
 
-  std::vector<RVA> abs32_locations_;
-  std::vector<std::unique_ptr<TypedRVA>> rel32_locations_;
+  // Sorted abs32 and reel32 RVAs. These are mutable because ParseFile() needs
+  // to sort these by file offsets.
+  mutable std::vector<RVA> abs32_locations_;
+  mutable std::vector<std::unique_ptr<TypedRVA>> rel32_locations_;
 
   DISALLOW_COPY_AND_ASSIGN(DisassemblerElf32);
 };