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

courgette/assembly_program.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COURGETTE_ASSEMBLY_PROGRAM_H_
 #define COURGETTE_ASSEMBLY_PROGRAM_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 39 matching lines @@
   explicit Instruction(OP op) : op_(op), info_(0) {}
   Instruction(OP op, unsigned int info) : op_(op), info_(info) {}
 
   uint32_t op_ : 4;     // A few bits to store the OP code.
   uint32_t info_ : 28;  // Remaining bits in first word available to subclass.
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Instruction);
 };
 
-typedef NoThrowBuffer<Instruction*> InstructionVector;
+// An interface to receive emitted instructions parsed from an executable.
+class InstructionReceptor {
+ public:
+  InstructionReceptor() = default;
+  virtual ~InstructionReceptor() = default;
+
+  // Generates an entire base relocation table.
+  virtual CheckBool EmitPeRelocs() = 0;
+
+  // Generates an ELF style relocation table for X86.
+  virtual CheckBool EmitElfRelocation() = 0;
+
+  // Generates an ELF style relocation table for ARM.
+  virtual CheckBool EmitElfARMRelocation() = 0;
+
+  // Following instruction will be assembled at address 'rva'.
+  virtual CheckBool EmitOrigin(RVA rva) = 0;
+
+  // Generates a single byte of data or machine instruction.
+  virtual CheckBool EmitSingleByte(uint8_t byte) = 0;
+
+  // Generates multiple bytes of data or machine instructions.
+  virtual CheckBool EmitMultipleBytes(const uint8_t* bytes, size_t len) = 0;
+
+  // Generates a 4-byte relative reference to address of 'label'.
+  virtual CheckBool EmitRel32(Label* label) = 0;
+
+  // Generates a 4-byte relative reference to address of 'label' for ARM.
+  virtual CheckBool EmitRel32ARM(uint16_t op,
+                                 Label* label,
+                                 const uint8_t* arm_op,
+                                 uint16_t op_size) = 0;
+
+  // Generates a 4-byte absolute reference to address of 'label'.
+  virtual CheckBool EmitAbs32(Label* label) = 0;
+
+  // Generates an 8-byte absolute reference to address of 'label'.
+  virtual CheckBool EmitAbs64(Label* label) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(InstructionReceptor);
+};
 
 // An AssemblyProgram is the result of disassembling an executable file.
 //
 // * The disassembler creates labels in the AssemblyProgram and emits
 //   'Instructions'.
 // * The disassembler then calls DefaultAssignIndexes to assign
 //   addresses to positions in the address tables.
 // * [Optional step]
 // * At this point the AssemblyProgram can be converted into an
 //   EncodedProgram and serialized to an output stream.
 // * Later, the EncodedProgram can be deserialized and assembled into
 //   the original file.
 //
 // The optional step is to modify the AssemblyProgram.  One form of modification
 // is to assign indexes in such a way as to make the EncodedProgram for this
 // AssemblyProgram look more like the EncodedProgram for some other
 // AssemblyProgram.  The modification process should call UnassignIndexes, do
 // its own assignment, and then call AssignRemainingIndexes to ensure all
 // indexes are assigned.
-//
+
 class AssemblyProgram {
  public:
   using LabelHandler = base::Callback<void(Label*)>;
   using LabelHandlerMap = std::map<OP, LabelHandler>;
 
+  // A callback for GenerateInstructions() to emit instructions. The first
+  // argument (AssemblyProgram*) is provided for Label-related feature access.
+  // The second argument (InstructionReceptor*) is a receptor for instructions.
+  // The callback (which gets called in 2 passes) should return true on success,
+  // and false otherwise.
+  using InstructionGenerator =
+      base::Callback<CheckBool(AssemblyProgram*, InstructionReceptor*)>;
+
   explicit AssemblyProgram(ExecutableType kind);
   ~AssemblyProgram();
 
   ExecutableType kind() const { return kind_; }
 
   void set_image_base(uint64_t image_base) { image_base_ = image_base; }
 
-  // Instructions will be assembled in the order they are emitted.
-
-  // Generates an entire base relocation table.
-  CheckBool EmitPeRelocsInstruction() WARN_UNUSED_RESULT;
-
-  // Generates an ELF style relocation table for X86.
-  CheckBool EmitElfRelocationInstruction() WARN_UNUSED_RESULT;
-
-  // Generates an ELF style relocation table for ARM.
-  CheckBool EmitElfARMRelocationInstruction() WARN_UNUSED_RESULT;
-
-  // Following instruction will be assembled at address 'rva'.
-  CheckBool EmitOriginInstruction(RVA rva) WARN_UNUSED_RESULT;
-
-  // Generates a single byte of data or machine instruction.
-  CheckBool EmitByteInstruction(uint8_t byte) WARN_UNUSED_RESULT;
-
-  // Generates multiple bytes of data or machine instructions.
-  CheckBool EmitBytesInstruction(const uint8_t* value,
-                                 size_t len) WARN_UNUSED_RESULT;
-
-  // Generates 4-byte relative reference to address of 'label'.
-  CheckBool EmitRel32(Label* label) WARN_UNUSED_RESULT;
-
-  // Generates 4-byte relative reference to address of 'label' for
-  // ARM.
-  CheckBool EmitRel32ARM(uint16_t op,
-                         Label* label,
-                         const uint8_t* arm_op,
-                         uint16_t op_size) WARN_UNUSED_RESULT;
-
-  // Generates 4-byte absolute reference to address of 'label'.
-  CheckBool EmitAbs32(Label* label) WARN_UNUSED_RESULT;
-
-  // Generates 8-byte absolute reference to address of 'label'.
-  CheckBool EmitAbs64(Label* label) WARN_UNUSED_RESULT;
-
   // Traverses RVAs in |abs32_visitor| and |rel32_visitor| to precompute Labels.
   void PrecomputeLabels(RvaVisitor* abs32_visitor, RvaVisitor* rel32_visitor);
 
   // Removes underused Labels. Thresholds used (0 = no trimming) is
   // architecture-dependent.
   void TrimLabels();
 
   void UnassignIndexes();
   void DefaultAssignIndexes();
   void AssignRemainingIndexes();
 
   // Looks up abs32 label. Returns null if none found.
   Label* FindAbs32Label(RVA rva);
 
   // Looks up rel32 label. Returns null if none found.
   Label* FindRel32Label(RVA rva);
 
   std::unique_ptr<EncodedProgram> Encode() const;
 
   // For each |instruction| in |instructions_|, looks up its opcode from
   // |handler_map| for a handler. If a handler exists, invoke it by passing the
   // |instruction|'s label. We assume that |handler_map| has correct keys, i.e.,
   // opcodes for an instruction that have label.
   void HandleInstructionLabels(const LabelHandlerMap& handler_map) const;
 
+  // Calls |gen| in 2 passes to emit instructions. In pass 1 we provide a
+  // receptor to count space requirement. In pass 2 we provide a receptor to
+  // store instructions.
+  CheckBool GenerateInstructions(const InstructionGenerator& gen);
+
+  // TODO(huangs): Implement these in InstructionStoreReceptor.
+  // Instructions will be assembled in the order they are emitted.
+
+  // Generates an entire base relocation table.
+  CheckBool EmitPeRelocs() WARN_UNUSED_RESULT;
+
+  // Generates an ELF style relocation table for X86.
+  CheckBool EmitElfRelocation() WARN_UNUSED_RESULT;
+
+  // Generates an ELF style relocation table for ARM.
+  CheckBool EmitElfARMRelocation() WARN_UNUSED_RESULT;
+
+  // Following instruction will be assembled at address 'rva'.
+  CheckBool EmitOrigin(RVA rva) WARN_UNUSED_RESULT;
+
+  // Generates a single byte of data or machine instruction.
+  CheckBool EmitSingleByte(uint8_t byte) WARN_UNUSED_RESULT;
+
+  // Generates multiple bytes of data or machine instructions.
+  CheckBool EmitMultipleBytes(const uint8_t* bytes,
+                              size_t len) WARN_UNUSED_RESULT;
+
+  // Generates a 4-byte relative reference to address of 'label'.
+  CheckBool EmitRel32(Label* label) WARN_UNUSED_RESULT;
+
+  // Generates a 4-byte relative reference to address of 'label' for ARM.
+  CheckBool EmitRel32ARM(uint16_t op,
+                         Label* label,
+                         const uint8_t* arm_op,
+                         uint16_t op_size) WARN_UNUSED_RESULT;
+
+  // Generates a 4-byte absolute reference to address of 'label'.
+  CheckBool EmitAbs32(Label* label) WARN_UNUSED_RESULT;
+
+  // Generates an 8-byte absolute reference to address of 'label'.
+  CheckBool EmitAbs64(Label* label) WARN_UNUSED_RESULT;
+
  private:
+  using InstructionVector = NoThrowBuffer<Instruction*>;
+
   using ScopedInstruction =
       std::unique_ptr<Instruction, UncheckedDeleter<Instruction>>;
 
   ExecutableType kind_;
 
   CheckBool Emit(ScopedInstruction instruction) WARN_UNUSED_RESULT;
   CheckBool EmitShared(Instruction* instruction) WARN_UNUSED_RESULT;
 
   static const int kLabelLowerLimit;
 
@@ skipping 23 matching lines @@
 
 // Converts |program| into encoded form, returning it as |*output|.
 // Returns C_OK if succeeded, otherwise returns an error status and sets
 // |*output| to null.
 Status Encode(const AssemblyProgram& program,
               std::unique_ptr<EncodedProgram>* output);
 
 }  // namespace courgette
 
 #endif  // COURGETTE_ASSEMBLY_PROGRAM_H_