ARM: support arguments access in lithium-codegen-arm.

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2010 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 1982 matching lines @@
 
 void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
   Register arguments = ToRegister(instr->arguments());
   Register length = ToRegister(instr->length());
   Operand index = ToOperand(instr->index());
   Register result = ToRegister(instr->result());
 
   __ sub(length, index);
   DeoptimizeIf(below_equal, instr->environment());
 
+  // There are two words between the frame pointer and the last argument.
+  // Subtracting from length accounts for one of them add one more.
   __ mov(result, Operand(arguments, length, times_4, kPointerSize));
 }
 
 
 void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
   Register elements = ToRegister(instr->elements());
   Register key = ToRegister(instr->key());
   Register result;
   if (instr->load_result() != NULL) {
     result = ToRegister(instr->load_result());
@@ skipping 29 matching lines @@
 
   Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
 }
 
 
 void LCodeGen::DoArgumentsElements(LArgumentsElements* instr) {
   Register result = ToRegister(instr->result());
 
   // Check for arguments adapter frame.
-  Label done, adapted;
+  NearLabel done, adapted;
   __ mov(result, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
   __ mov(result, Operand(result, StandardFrameConstants::kContextOffset));
   __ cmp(Operand(result),
          Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
   __ j(equal, &adapted);
 
   // No arguments adaptor frame.
   __ mov(result, Operand(ebp));
   __ jmp(&done);
 
   // Arguments adaptor frame present.
   __ bind(&adapted);
   __ mov(result, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
 
-  // Done. Pointer to topmost argument is in result.
+  // Result is the frame pointer for the frame if not adapted and for the real
+  // frame below the adaptor frame if adapted.
   __ bind(&done);
 }
 
 
 void LCodeGen::DoArgumentsLength(LArgumentsLength* instr) {
   Operand elem = ToOperand(instr->input());
   Register result = ToRegister(instr->result());
 
-  Label done;
+  NearLabel done;
 
-  // No arguments adaptor frame. Number of arguments is fixed.
+  // If no arguments adaptor frame the number of arguments is fixed.
   __ cmp(ebp, elem);
   __ mov(result, Immediate(scope()->num_parameters()));
   __ j(equal, &done);
 
   // Arguments adaptor frame present. Get argument length from there.
   __ mov(result, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
   __ mov(result, Operand(result,
                          ArgumentsAdaptorFrameConstants::kLengthOffset));
   __ SmiUntag(result);
 
-  // Done. Argument length is in result register.
+  // Argument length is in result register.
   __ bind(&done);
 }
 
 
 void LCodeGen::DoApplyArguments(LApplyArguments* instr) {
   Register receiver = ToRegister(instr->receiver());
   ASSERT(ToRegister(instr->function()).is(edi));
   ASSERT(ToRegister(instr->result()).is(eax));
 
   // If the receiver is null or undefined, we have to pass the
@@ skipping 1301 matching lines @@
   ASSERT(!environment->HasBeenRegistered());
   RegisterEnvironmentForDeoptimization(environment);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal