[turbofan] cleanup InstructionSequence

src/compiler/code-generator.h

Index: src/compiler/code-generator.h
diff --git a/src/compiler/code-generator.h b/src/compiler/code-generator.h
index 8b1c9d58eec96d427af67af7131dabcc3680ff65..f3ef1ce6e0d895b93a7c5a6256c33d3a2a313211 100644
--- a/src/compiler/code-generator.h
+++ b/src/compiler/code-generator.h
@@ -20,15 +20,16 @@ namespace compiler {
 // Generates native code for a sequence of instructions.
 class CodeGenerator FINAL : public GapResolver::Assembler {
  public:
-  explicit CodeGenerator(InstructionSequence* code);
+  explicit CodeGenerator(Frame* frame, Linkage* linkage,
+                         InstructionSequence* code);
 
   // Generate native code.
   Handle<Code> GenerateCode();
 
   InstructionSequence* code() const { return code_; }
-  Frame* frame() const { return code()->frame(); }
+  Frame* frame() const { return frame_; }
   Isolate* isolate() const { return zone()->isolate(); }
-  Linkage* linkage() const { return code()->linkage(); }
+  Linkage* linkage() const { return linkage_; }
 
  private:
   MacroAssembler* masm() { return &masm_; }
@@ -116,7 +117,9 @@ class CodeGenerator FINAL : public GapResolver::Assembler {
     int pc_offset_;
   };
 
-  InstructionSequence* code_;
+  Frame* const frame_;
+  Linkage* const linkage_;
+  InstructionSequence* const code_;
   BasicBlock::RpoNumber current_block_;
   SourcePosition current_source_position_;
   MacroAssembler masm_;