Simplify and fix code aging.

src/mips/full-codegen-mips.cc

 // Copyright 2012 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 140 matching lines @@
     __ stop("stop-at");
   }
 #endif
 
   // Strict mode functions and builtins need to replace the receiver
   // with undefined when called as functions (without an explicit
   // receiver object). t1 is zero for method calls and non-zero for
   // function calls.
   if (!info->is_classic_mode() || info->is_native()) {
     Label ok;
-    Label begin;
-    __ bind(&begin);
     __ Branch(&ok, eq, t1, Operand(zero_reg));
     int receiver_offset = info->scope()->num_parameters() * kPointerSize;
     __ LoadRoot(a2, Heap::kUndefinedValueRootIndex);
     __ sw(a2, MemOperand(sp, receiver_offset));
     __ bind(&ok);
-    ASSERT_EQ(kSizeOfFullCodegenStrictModePrologue, ok.pos() - begin.pos());
   }
 
   // Open a frame scope to indicate that there is a frame on the stack.  The
   // MANUAL indicates that the scope shouldn't actually generate code to set up
   // the frame (that is done below).
   FrameScope frame_scope(masm_, StackFrame::MANUAL);
 
   int locals_count = info->scope()->num_stack_slots();
 
+  info->set_prologue_offset(masm_->pc_offset());
   // The following three instructions must remain together and unmodified for
   // code aging to work properly.
   __ Push(ra, fp, cp, a1);
   // Load undefined value here, so the value is ready for the loop
   // below.
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
   // Adjust fp to point to caller's fp.
   __ Addu(fp, sp, Operand(2 * kPointerSize));
 
   { Comment cmnt(masm_, "[ Allocate locals");
@@ skipping 4369 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS