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

courgette/disassembler_win32.cc

Index: courgette/disassembler_win32.cc
diff --git a/courgette/disassembler_win32.cc b/courgette/disassembler_win32.cc
index c039dd346a60fb5722aa976ed782c65596941279..b7dd7a9d53c84c9fbf97a10dbc89bebecc8c6a2c 100644
--- a/courgette/disassembler_win32.cc
+++ b/courgette/disassembler_win32.cc
@@ -237,8 +237,18 @@ bool DisassemblerWin32::Disassemble(AssemblyProgram* target) {
   PrecomputeLabels(target);
   RemoveUnusedRel32Locations(target);
 
-  if (!ParseFile(target))
+  // Pass 1: Count the space needed to store instructions.
+  InstructionCountReceptor* count_receptor = nullptr;
+  if (!target->CreateInstructionCountReceptor(&count_receptor) ||
+      !ParseFile(target, count_receptor)) {
     return false;
+  }
+  // Pass 2: Emit all instructions.
+  InstructionStoreReceptor* store_receptor = nullptr;
+  if (!target->CreateInstructionStoreReceptor(&store_receptor) ||
+      !ParseFile(target, store_receptor)) {
+    return false;
+  }
 
   target->DefaultAssignIndexes();
 
@@ -388,7 +398,8 @@ void DisassemblerWin32::RemoveUnusedRel32Locations(
       rel32_locations_.end());
 }
 
-CheckBool DisassemblerWin32::ParseFile(AssemblyProgram* program) {
+CheckBool DisassemblerWin32::ParseFile(AssemblyProgram* program,
+                                       InstructionReceptor* receptor) const {
   // Walk all the bytes in the file, whether or not in a section.
   FileOffset file_offset = 0;
   while (file_offset < length()) {
@@ -396,20 +407,20 @@ CheckBool DisassemblerWin32::ParseFile(AssemblyProgram* program) {
     if (section == nullptr) {
       // No more sections. There should not be extra stuff following last
       // section.
-      //   ParseNonSectionFileRegion(file_offset, pe_info().length(), program);
+      //   ParseNonSectionFileRegion(file_offset, pe_info().length(), receptor);
       break;
     }
     if (file_offset < section->file_offset_of_raw_data) {
       FileOffset section_start_offset = section->file_offset_of_raw_data;
       if (!ParseNonSectionFileRegion(file_offset, section_start_offset,
-                                     program)) {
+                                     receptor)) {
         return false;
       }
 
       file_offset = section_start_offset;
     }
     FileOffset end = file_offset + section->size_of_raw_data;
-    if (!ParseFileRegion(section, file_offset, end, program))
+    if (!ParseFileRegion(section, file_offset, end, program, receptor))
       return false;
     file_offset = end;
   }
@@ -479,13 +490,13 @@ void DisassemblerWin32::ParseRel32RelocsFromSections() {
 CheckBool DisassemblerWin32::ParseNonSectionFileRegion(
     FileOffset start_file_offset,
     FileOffset end_file_offset,
-    AssemblyProgram* program) {
+    InstructionReceptor* receptor) const {
   if (incomplete_disassembly_)
     return true;
 
   if (end_file_offset > start_file_offset) {
-    if (!program->EmitBytesInstruction(FileOffsetToPointer(start_file_offset),
-                                       end_file_offset - start_file_offset)) {
+    if (!receptor->EmitMultipleBytes(FileOffsetToPointer(start_file_offset),
+                                     end_file_offset - start_file_offset)) {
       return false;
     }
   }
@@ -493,10 +504,12 @@ CheckBool DisassemblerWin32::ParseNonSectionFileRegion(
   return true;
 }
 
-CheckBool DisassemblerWin32::ParseFileRegion(const Section* section,
-                                             FileOffset start_file_offset,
-                                             FileOffset end_file_offset,
-                                             AssemblyProgram* program) {
+CheckBool DisassemblerWin32::ParseFileRegion(
+    const Section* section,
+    FileOffset start_file_offset,
+    FileOffset end_file_offset,
+    AssemblyProgram* program,
+    InstructionReceptor* receptor) const {
   RVA relocs_start_rva = base_relocation_table().address_;
 
   const uint8_t* start_pointer = FileOffsetToPointer(start_file_offset);
@@ -510,10 +523,10 @@ CheckBool DisassemblerWin32::ParseFileRegion(const Section* section,
   // subtract 'pointer_to_rva'.
   const uint8_t* const adjust_pointer_to_rva = start_pointer - start_rva;
 
-  std::vector<RVA>::iterator rel32_pos = rel32_locations_.begin();
-  std::vector<RVA>::iterator abs32_pos = abs32_locations_.begin();
+  std::vector<RVA>::const_iterator rel32_pos = rel32_locations_.begin();
+  std::vector<RVA>::const_iterator abs32_pos = abs32_locations_.begin();
 
-  if (!program->EmitOriginInstruction(start_rva))
+  if (!receptor->EmitOrigin(start_rva))
     return false;
 
   const uint8_t* p = start_pointer;
@@ -525,7 +538,7 @@ CheckBool DisassemblerWin32::ParseFileRegion(const Section* section,
     // actually be anywhere.  Make sure we skip it because we will regenerate it
     // during assembly.
     if (current_rva == relocs_start_rva) {
-      if (!program->EmitPeRelocsInstruction())
+      if (!receptor->EmitPeRelocs())
         return false;
       uint32_t relocs_size = base_relocation_table().size_;
       if (relocs_size) {
@@ -544,7 +557,7 @@ CheckBool DisassemblerWin32::ParseFileRegion(const Section* section,
       // which it might be.  We assume offset==0.
       Label* label = program->FindAbs32Label(target_rva);
       DCHECK(label);
-      if (!EmitAbs(label, program))
+      if (!EmitAbs(label, receptor))
         return false;
       p += kVAWidth;
       continue;
@@ -558,7 +571,7 @@ CheckBool DisassemblerWin32::ParseFileRegion(const Section* section,
       RVA target_rva = current_rva + 4 + Read32LittleEndian(p);
       Label* label = program->FindRel32Label(target_rva);
       DCHECK(label);
-      if (!program->EmitRel32(label))
+      if (!receptor->EmitRel32(label))
         return false;
       p += 4;
       continue;
@@ -573,7 +586,7 @@ CheckBool DisassemblerWin32::ParseFileRegion(const Section* section,
       }
     }
 
-    if (!program->EmitByteInstruction(*p))
+    if (!receptor->EmitSingleByte(*p))
       return false;
     p += 1;
   }
@@ -587,7 +600,7 @@ CheckBool DisassemblerWin32::ParseFileRegion(const Section* section,
 // command-line configuration for this feature because this code has to be
 // small, which means compiled-out.
 void DisassemblerWin32::HistogramTargets(const char* kind,
-                                         const std::map<RVA, int>& map) {
+                                         const std::map<RVA, int>& map) const {
   int total = 0;
   std::map<int, std::vector<RVA>> h;
   for (std::map<RVA, int>::const_iterator p = map.begin(); p != map.end();