Rename JumpToBuiltin to JumpToRuntime. Add comment to ResolveBuiltin.

src/x64/macro-assembler-x64.h

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 518 matching lines @@
   void StubReturn(int argc);
 
   // Call a runtime routine.
   // Eventually this should be used for all C calls.
   void CallRuntime(Runtime::Function* f, int num_arguments);
 
   // Convenience function: Same as above, but takes the fid instead.
   void CallRuntime(Runtime::FunctionId id, int num_arguments);
 
   // Tail call of a runtime routine (jump).
-  // Like JumpToBuiltin, but also takes care of passing the number
+  // Like JumpToRuntime, but also takes care of passing the number
   // of arguments.
   void TailCallRuntime(const ExternalReference& ext,
                        int num_arguments,
                        int result_size);
 
-  // Jump to the builtin routine.
-  void JumpToBuiltin(const ExternalReference& ext, int result_size);
+  // Jump to a runtime routine.
+  void JumpToRuntime(const ExternalReference& ext, int result_size);
 
 
   // ---------------------------------------------------------------------------
   // Utilities
 
   void Ret();
 
   struct Unresolved {
     int pc;
     uint32_t flags;  // see Bootstrapper::FixupFlags decoders/encoders.
@@ skipping 39 matching lines @@
                                 // object on installation.
 
   // Helper functions for generating invokes.
   void InvokePrologue(const ParameterCount& expected,
                       const ParameterCount& actual,
                       Handle<Code> code_constant,
                       Register code_register,
                       Label* done,
                       InvokeFlag flag);
 
-  // Get the code for the given builtin. Returns if able to resolve
-  // the function in the 'resolved' flag.
+  // Prepares for a call or jump to a builtin by doing two things:
+  // 1. Emits code that fetches the builtin's function object from the context
+  //    at runtime, and puts it in the register rdi.
+  // 2. Fetches the builtin's code object, and returns it in a handle, at
+  //    compile time, so that later code can emit instructions to jump or call
+  //    the builtin directly.  If the code object has not yet been created, it
+  //    returns the builtin code object for IllegalFunction, and sets the
+  //    output parameter "resolved" to false.  Code that uses the return value
+  //    should then add the address and the builtin name to the list of fixups
+  //    called unresolved_, which is fixed up by the bootstrapper.
   Handle<Code> ResolveBuiltin(Builtins::JavaScript id, bool* resolved);
 
   // Activation support.
   void EnterFrame(StackFrame::Type type);
   void LeaveFrame(StackFrame::Type type);
 
   // Allocation support helpers.
   void LoadAllocationTopHelper(Register result,
                                Register result_end,
                                Register scratch,
@@ skipping 58 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_