X64: Abstract indexing by a smi to the macro assembler.

src/x64/codegen-x64.cc

 // 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 1710 matching lines @@
   // targets only after all the state is pushed on the frame.
   node->break_target()->set_direction(JumpTarget::FORWARD_ONLY);
   node->continue_target()->set_direction(JumpTarget::FORWARD_ONLY);
 
   __ movq(rax, frame_->ElementAt(0));  // load the current count
   __ cmpl(rax, frame_->ElementAt(1));  // compare to the array length
   node->break_target()->Branch(above_equal);
 
   // Get the i'th entry of the array.
   __ movq(rdx, frame_->ElementAt(2));
-  // TODO(smi): Find a way to abstract indexing by a smi value.
-  ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
-  // Multiplier is times_4 since rax is already a Smi.
-  __ movq(rbx, FieldOperand(rdx, rax, times_4, FixedArray::kHeaderSize));
+  SmiIndex index = masm_->SmiToIndex(rbx, rax, kPointerSizeLog2);
+  __ movq(rbx,
+          FieldOperand(rdx, index.reg, index.scale, FixedArray::kHeaderSize));
 
   // Get the expected map from the stack or a zero map in the
   // permanent slow case rax: current iteration count rbx: i'th entry
   // of the enum cache
   __ movq(rdx, frame_->ElementAt(3));
   // Check if the expected map still matches that of the enumerable.
   // If not, we have to filter the key.
   // rax: current iteration count
   // rbx: i'th entry of the enum cache
   // rdx: expected map value
@@ skipping 2134 matching lines @@
   left.ToRegister();
   __ cmpq(right.reg(), left.reg());
   right.Unuse();
   left.Unuse();
   destination()->Split(equal);
 }
 
 
 void CodeGenerator::GenerateGetFramePointer(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 0);
-  ASSERT(kSmiTag == 0);  // RBP value is aligned, so it should look like Smi.
+  // RBP value is aligned, so it should be tagged as a smi (without necesarily
+  // being padded as a smi).
+  ASSERT(kSmiTag == 0 && kSmiTagSize == 1);
   Result rbp_as_smi = allocator_->Allocate();
   ASSERT(rbp_as_smi.is_valid());
   __ movq(rbp_as_smi.reg(), rbp);
   frame_->Push(&rbp_as_smi);
 }
 
 
 void CodeGenerator::GenerateRandomPositiveSmi(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 0);
   frame_->SpillAll();
@@ skipping 2220 matching lines @@
         __ bind(deferred->patch_site());
         // Avoid using __ to ensure the distance from patch_site
         // to the map address is always the same.
         masm->movq(kScratchRegister, Factory::fixed_array_map(),
                    RelocInfo::EMBEDDED_OBJECT);
         __ cmpq(FieldOperand(tmp.reg(), HeapObject::kMapOffset),
                 kScratchRegister);
         deferred->Branch(not_equal);
 
         // Store the value.
-        ASSERT_EQ(1, kSmiTagSize);
-        ASSERT_EQ(0, kSmiTag);
-        // TODO(lrn) Find way to abstract indexing by smi.
-        __ movq(Operand(tmp.reg(),
-                        key.reg(),
-                        times_half_pointer_size,
+        SmiIndex index =
+            masm->SmiToIndex(kScratchRegister, key.reg(), kPointerSizeLog2);
+              __ movq(Operand(tmp.reg(),
+                        index.reg,
+                        index.scale,
                         FixedArray::kHeaderSize - kHeapObjectTag),
                 value.reg());
         __ IncrementCounter(&Counters::keyed_store_inline, 1);
 
         deferred->BindExit();
 
         cgen_->frame()->Push(&receiver);
         cgen_->frame()->Push(&key);
         cgen_->frame()->Push(&value);
       } else {
@@ skipping 507 matching lines @@
   Label runtime;
   __ movq(rdx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
   __ movq(rcx, Operand(rdx, StandardFrameConstants::kContextOffset));
   __ cmpq(rcx, Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
   __ j(not_equal, &runtime);
   // Value in rcx is Smi encoded.
 
   // Patch the arguments.length and the parameters pointer.
   __ movq(rcx, Operand(rdx, ArgumentsAdaptorFrameConstants::kLengthOffset));
   __ movq(Operand(rsp, 1 * kPointerSize), rcx);
-  __ lea(rdx, Operand(rdx, rcx, times_4, kDisplacement));
+  SmiIndex index = masm->SmiToIndex(rcx, rcx, kPointerSizeLog2);
+  __ lea(rdx, Operand(rdx, index.reg, index.scale, kDisplacement));
   __ movq(Operand(rsp, 2 * kPointerSize), rdx);
 
   // Do the runtime call to allocate the arguments object.
   __ bind(&runtime);
   Runtime::Function* f = Runtime::FunctionForId(Runtime::kNewArgumentsFast);
   __ TailCallRuntime(ExternalReference(f), 3, f->result_size);
 }
 
 
 void ArgumentsAccessStub::GenerateReadElement(MacroAssembler* masm) {
@@ skipping 15 matching lines @@
   __ cmpq(rcx, Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
   __ j(equal, &adaptor);
 
   // Check index against formal parameters count limit passed in
   // through register rax. Use unsigned comparison to get negative
   // check for free.
   __ cmpq(rdx, rax);
   __ j(above_equal, &slow);
 
   // Read the argument from the stack and return it.
-  // Shifting code depends on SmiEncoding being equivalent to left shift:
-  // we multiply by four to get pointer alignment.
-  // TODO(smi): Find a way to abstract indexing by a smi.
-  ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
-  __ lea(rbx, Operand(rbp, rax, times_4, 0));
-  __ neg(rdx);  // TODO(smi): Abstract negative indexing too.
-  __ movq(rax, Operand(rbx, rdx, times_4, kDisplacement));
+  SmiIndex index = masm->SmiToIndex(rax, rax, kPointerSizeLog2);
+  __ lea(rbx, Operand(rbp, index.reg, index.scale, 0));
+  index = masm->SmiToNegativeIndex(rdx, rdx, kPointerSizeLog2);
+  __ movq(rax, Operand(rbx, index.reg, index.scale, kDisplacement));
   __ Ret();
 
   // Arguments adaptor case: Check index against actual arguments
   // limit found in the arguments adaptor frame. Use unsigned
   // comparison to get negative check for free.
   __ bind(&adaptor);
   __ movq(rcx, Operand(rbx, ArgumentsAdaptorFrameConstants::kLengthOffset));
   __ cmpq(rdx, rcx);
   __ j(above_equal, &slow);
 
   // Read the argument from the stack and return it.
-  // Shifting code depends on SmiEncoding being equivalent to left shift:
-  // we multiply by four to get pointer alignment.
-  // TODO(smi): Find a way to abstract indexing by a smi.
-  ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
-  __ lea(rbx, Operand(rbx, rcx, times_4, 0));
-  __ neg(rdx);
-  __ movq(rax, Operand(rbx, rdx, times_4, kDisplacement));
+  index = masm->SmiToIndex(rbx, rcx, kPointerSizeLog2);
+  __ lea(rbx, Operand(rbx, index.reg, index.scale, 0));
+  index = masm->SmiToNegativeIndex(rdx, rdx, kPointerSizeLog2);
+  __ movq(rax, Operand(rbx, index.reg, index.scale, kDisplacement));
   __ Ret();
 
   // Slow-case: Handle non-smi or out-of-bounds access to arguments
   // by calling the runtime system.
   __ bind(&slow);
   __ pop(rbx);  // Return address.
   __ push(rdx);
   __ push(rbx);
   Runtime::Function* f =
       Runtime::FunctionForId(Runtime::kGetArgumentsProperty);
@@ skipping 954 matching lines @@
 int CompareStub::MinorKey() {
   // Encode the two parameters in a unique 16 bit value.
   ASSERT(static_cast<unsigned>(cc_) < (1 << 15));
   return (static_cast<unsigned>(cc_) << 1) | (strict_ ? 1 : 0);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal