[Arguments] Port fast arguments creation stubs to X64 and ARM.

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 52b1d288fe8dfaf0ca187b512edf9ac584393f4f..a6dcda84d506f7c0e446684e06847488c674fbf5 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -3938,21 +3938,240 @@ void ArgumentsAccessStub::GenerateReadElement(MacroAssembler* masm) {
 }
 
 
-void ArgumentsAccessStub::GenerateNewStrict(MacroAssembler* masm) {
-  UNIMPLEMENTED();
+void ArgumentsAccessStub::GenerateNewNonStrictSlow(MacroAssembler* masm) {
+  // sp[0] : number of parameters
+  // sp[4] : receiver displacement
+  // sp[8] : function
+
+  // Check if the calling frame is an arguments adaptor frame.
+  Label runtime;
+  __ ldr(r3, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+  __ ldr(r2, MemOperand(r3, StandardFrameConstants::kContextOffset));
+  __ cmp(r2, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
+  __ b(ne, &runtime);
+
+  // Patch the arguments.length and the parameters pointer in the current frame.
+  __ ldr(r2, MemOperand(r3, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  __ str(r2, MemOperand(sp, 0 * kPointerSize));
+  __ add(r3, r3, Operand(r2, LSL, 1));
+  __ add(r3, r3, Operand(StandardFrameConstants::kCallerSPOffset));
+  __ str(r3, MemOperand(sp, 1 * kPointerSize));
+
+  __ bind(&runtime);
+  __ TailCallRuntime(Runtime::kNewArgumentsFast, 3, 1);
 }
 
 
 void ArgumentsAccessStub::GenerateNewNonStrictFast(MacroAssembler* masm) {
-  UNIMPLEMENTED();
+  // Stack layout:
+  //  sp[0] : number of parameters (tagged)
+  //  sp[4] : address of receiver argument
+  //  sp[8] : function
+  // Registers used over whole function:
+  //  r6 : allocated object (tagged)
+  //  r9 : mapped parameter count (tagged)
+
+  // r1 = parameter count (untagged)

[Kevin Millikin (Chromium), 2011/06/07 13:54:10]

(untagged) ==> (tagged)

[Karl Klose, 2011/06/10 11:32:22]

Done.

+  __ ldr(r1, MemOperand(sp, 0 * kPointerSize));
+
+  // Check if the calling frame is an arguments adaptor frame.
+  Label runtime;
+  Label adaptor_frame, try_allocate;
+  __ ldr(r3, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+  __ ldr(r2, MemOperand(r3, StandardFrameConstants::kContextOffset));
+  __ cmp(r2, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
+  __ b(eq, &adaptor_frame);
+
+  // No adaptor, parameter count = argument count.
+  __ mov(r2, r1);
+  __ b(&try_allocate);
+
+  // We have an adaptor frame. Patch the parameters pointer.
+  __ bind(&adaptor_frame);
+  __ ldr(r2, MemOperand(r3, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  __ add(r3, r3, Operand(r2, LSL, 1));
+  __ add(r3, r3, Operand(StandardFrameConstants::kCallerSPOffset));
+  __ str(r3, MemOperand(sp, 1 * kPointerSize));
+
+  // r1 = parameter count (tagged)
+  // r2 = argument count (tagged)
+  // Compute the mapped parameter count = min(r1, r2) in r1.
+  __ cmp(r1, Operand(r2));
+  __ mov(r1, Operand(r2), LeaveCC, gt);
+
+  __ bind(&try_allocate);
+  // Save mapped parameter count.
+  __ mov(r9, r1);
+
+  // Compute the sizes of backing store, parameter map, and arguments object.
+  // 1. Parameter map, has 2 extra words containing context and backing store.
+  const int kParameterMapHeaderSize =
+      FixedArray::kHeaderSize + 2 * kPointerSize;
+  // If there are no mapped parameters, we do not need the parameter_map.
+  __ cmp(r1, Operand(0));

[Kevin Millikin (Chromium), 2011/06/07 13:54:10]

Since r1 is tagged, can we use Smi::FromInt(0)?

[Karl Klose, 2011/06/10 11:32:22]

Done.

+  __ mov(r1, Operand(r1, LSL, 1), LeaveCC, ne);
+  __ add(r1, r1, Operand(kParameterMapHeaderSize), LeaveCC, ne);
+
+  // 2. Backing store.
+  __ add(r1, r1, Operand(r2, LSL, 1));
+  __ add(r1, r1, Operand(FixedArray::kHeaderSize));
+
+  // 3. Arguments object.
+  __ add(r1, r1, Operand(Heap::kArgumentsObjectSize));
+
+  // Do the allocation of all three objects in one go.
+  __ AllocateInNewSpace(r1, r0, r3, r4, &runtime, TAG_OBJECT);
+
+  // r0 = address of new object(s) (tagged)
+  // r2 = argument count (tagged)
+  // Get the arguments boilerplate from the current (global) context into r4.
+  const int kNormalOffset =
+      Context::SlotOffset(Context::ARGUMENTS_BOILERPLATE_INDEX);
+  const int kAliasedOffset =
+      Context::SlotOffset(Context::ALIASED_ARGUMENTS_BOILERPLATE_INDEX);
+
+  __ ldr(r4, MemOperand(r8, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ ldr(r4, FieldMemOperand(r4, GlobalObject::kGlobalContextOffset));
+  __ mov(r1, r9);
+  __ SmiUntag(r1);

[Kevin Millikin (Chromium), 2011/06/07 13:54:10]

Hmm, if I correctly follow this, the untagged r1 is used in a couple of compares
to 0 and then to compute the length of the parameter map, which is tagged before
storing it in the fixed array.

So I think we could avoid untagging it here, compare to Smi::FromInt(0), and
compute the tagged length directly.

[Karl Klose, 2011/06/10 11:32:22]

Done.

+  __ cmp(r1, Operand(0));
+  __ ldr(r4, MemOperand(r4, kNormalOffset), eq);
+  __ ldr(r4, MemOperand(r4, kAliasedOffset), ne);
+
+  // r0 = address of new object (tagged)
+  // r1 = mapped parameter count (untagged)
+  // r2 = argument count (untagged)

[Kevin Millikin (Chromium), 2011/06/07 13:54:10]

(untagged) ==> (tagged)

[Karl Klose, 2011/06/10 11:32:22]

Done.

+  // r4 = address of boilerplate object (tagged)
+  // Copy the JS object part.
+  for (int i = 0; i < JSObject::kHeaderSize; i += kPointerSize) {
+    __ ldr(r3, FieldMemOperand(r4, i));
+    __ str(r3, FieldMemOperand(r0, i));
+  }
+
+  // Setup the callee in-object property.
+  STATIC_ASSERT(Heap::kArgumentsCalleeIndex == 1);
+  __ ldr(r3, MemOperand(sp, 2 * kPointerSize));
+  const int kCalleeOffset = JSObject::kHeaderSize +
+      Heap::kArgumentsCalleeIndex * kPointerSize;
+  __ str(r3, FieldMemOperand(r0, kCalleeOffset));
+
+  // Use the length (smi tagged) and set that as an in-object property too.
+  STATIC_ASSERT(Heap::kArgumentsLengthIndex == 0);
+  const int kLengthOffset = JSObject::kHeaderSize +
+      Heap::kArgumentsLengthIndex * kPointerSize;
+  __ str(r2, FieldMemOperand(r0, kLengthOffset));
+
+  // Setup the elements pointer in the allocated arguments object.
+  // If we allocated a parameter map, r4 will point there, otherwise
+  // it will point to the backing store.
+  __ add(r4, r0, Operand(Heap::kArgumentsObjectSize));
+  __ str(r4, FieldMemOperand(r0, JSObject::kElementsOffset));
+
+  // r0 = address of new object (tagged)
+  // r1 = mapped parameter count (untagged)
+  // r2 = argument count (tagged)
+  // r4 = address of parameter map or backing store (tagged)
+  __ mov(r6, r0);

[Kevin Millikin (Chromium), 2011/06/07 13:54:10]

This mov might be unnecessary.  Can r6 be used instead of r0 below, preserving
the object in r0?

+
+  // Initialize parameter map. If there are no mapped arguments, we're done.
+  Label skip_parameter_map;
+  __ cmp(r1, Operand(0));
+  __ b(eq, &skip_parameter_map);
+
+  __ LoadRoot(r0, Heap::kNonStrictArgumentsElementsMapRootIndex);
+  __ str(r0, FieldMemOperand(r4, FixedArray::kMapOffset));
+  __ add(r0, r1, Operand(2));
+  __ SmiTag(r0);
+  __ str(r0, FieldMemOperand(r4, FixedArray::kLengthOffset));
+  __ str(r8, FieldMemOperand(r4, FixedArray::kHeaderSize + 0 * kPointerSize));
+  __ add(r0, r4, Operand(r1, LSL, 2));
+  __ add(r0, r0, Operand(kParameterMapHeaderSize));
+  __ str(r0, FieldMemOperand(r4, FixedArray::kHeaderSize + 1 * kPointerSize));
+
+  // Copy the parameter slots and the holes in the arguments.
+  // We need to fill in mapped_parameter_count slots. They index the context,
+  // where parameters are stored in reverse order, at
+  //   MIN_CONTEXT_SLOTS .. MIN_CONTEXT_SLOTS+parameter_count-1
+  // The mapped parameter thus need to get indices
+  //   MIN_CONTEXT_SLOTS+parameter_count-1 ..
+  //       MIN_CONTEXT_SLOTS+parameter_count-mapped_parameter_count
+  // We loop from right to left.
+  Label parameters_loop, parameters_test;
+  __ mov(r0, r9);
+  __ ldr(r1, MemOperand(sp, 0 * kPointerSize));
+  __ add(r1, r1, Operand(Smi::FromInt(Context::MIN_CONTEXT_SLOTS)));
+  __ sub(r1, r1, Operand(r0));
+  __ LoadRoot(r7, Heap::kTheHoleValueRootIndex);
+  __ mov(r3, r4);

[Kevin Millikin (Chromium), 2011/06/07 13:54:10]

Can we avoid this mov by using r3 instead of r4 below:

__ add(r3, r4, Operand(r5, LSL, 2));
__ add(r3, r3, Operand(kParameterMapHeaderSize));
...

[Karl Klose, 2011/06/10 11:32:22]

Done. The tricky part is that this code can be jumped over, so I had to
introduce a conditional move at line 4079.

+  __ mov(r5, r0);
+  __ SmiUntag(r5);

[Kevin Millikin (Chromium), 2011/06/07 13:54:10]

Is this untagged and retagged at its use?  Maybe my ARM code is rusty, but I
thought:

// No mov(r5, r0) or SmiUntag(r5).
__ add(r4, r4, Operand(r0, LSL, 1));
__ add(r4, r4, Operand(kParameterMapHeaderSize));

[Karl Klose, 2011/06/10 11:32:22]

You are right, this is unnecessary.

+  __ add(r4, r4, Operand(r5, LSL, 2));
+  __ add(r4, r4, Operand(kParameterMapHeaderSize));
+
+  // r0 = loop variable (tagged)
+  // r1 = mapping index (tagged)
+  // r3 = address of parameter map (tagged)
+  // r4 = address of backing store (tagged)
+  // r5 = temporary scratch (a.o., for address calculation)
+  // r7 = the hole value
+  __ jmp(&parameters_test);
+
+  __ bind(&parameters_loop);
+  __ sub(r0, r0, Operand(Smi::FromInt(1)));
+  __ mov(r5, Operand(r0, LSL, 1));

[Kevin Millikin (Chromium), 2011/06/07 13:54:10]

The computation of this value in r5 is duplicated just below.  Can we avoid it
with:

__ mov(r5, Operand(r0, LSL, 1));
__ add(r5, r5, Operand(kParameterMapHeaderSize - kHeapObjectTag));
__ str(r1, MemOperand(r3, r5));
__ sub(r5, r5, Operand(kParameterMapHeaderSize - FixedArray::kHeaderSize));
__ str(r7, MemOperand(r4, r5));

[Karl Klose, 2011/06/10 11:32:22]

Done. It makes the code slightly harder to understand, but it should be ok here.

+  __ add(r5, r5, Operand(kParameterMapHeaderSize - kHeapObjectTag));
+  __ str(r1, MemOperand(r3, r5));
+  __ mov(r5, Operand(r0, LSL, 1));
+  __ add(r5, r5, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
+  __ str(r7, MemOperand(r4, r5));
+  __ add(r1, r1, Operand(Smi::FromInt(1)));
+  __ bind(&parameters_test);
+  __ cmp(r0, Operand(0));
+  __ b(ne, &parameters_loop);
+
+  __ bind(&skip_parameter_map);
+  // r2 = argument count (tagged)
+  // r4 = address of backing store (tagged)
+  // r5 = scratch
+  // Copy arguments header and remaining slots (if there are any).
+  __ LoadRoot(r5, Heap::kFixedArrayMapRootIndex);
+  __ str(r5, FieldMemOperand(r4, FixedArray::kMapOffset));
+  __ str(r2, FieldMemOperand(r4, FixedArray::kLengthOffset));
+
+  Label arguments_loop, arguments_test;
+  __ mov(r1, r9);
+  __ ldr(r3, MemOperand(sp, 1 * kPointerSize));
+  __ sub(r3, r3, Operand(r1, LSL, 1));
+  __ jmp(&arguments_test);
+
+  __ bind(&arguments_loop);
+  __ sub(r3, r3, Operand(kPointerSize));
+  __ ldr(r0, MemOperand(r3, 0));
+  __ add(r5, r4, Operand(r1, LSL, 1));
+  __ str(r0, FieldMemOperand(r5, FixedArray::kHeaderSize));
+  __ add(r1, r1, Operand(Smi::FromInt(1)));
+
+  __ bind(&arguments_test);
+  __ cmp(r1, Operand(r2));
+  __ b(lt, &arguments_loop);
+
+  // Return and remove the on-stack parameters.
+  __ add(sp, sp, Operand(3 * kPointerSize));
+  __ mov(r0, r6);
+  __ Ret();
+
+  // Do the runtime call to allocate the arguments object.
+  // r2 = argument count (taggged)
+  __ bind(&runtime);
+  __ str(r2, MemOperand(sp, 0 * kPointerSize));  // Patch argument count.
+  __ TailCallRuntime(Runtime::kNewArgumentsFast, 3, 1);
 }
 
 
-void ArgumentsAccessStub::GenerateNewNonStrictSlow(MacroAssembler* masm) {
+void ArgumentsAccessStub::GenerateNewStrict(MacroAssembler* masm) {
   // sp[0] : number of parameters
   // sp[4] : receiver displacement
   // sp[8] : function
-
   // Check if the calling frame is an arguments adaptor frame.
   Label adaptor_frame, try_allocate, runtime;
   __ ldr(r2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
@@ -3976,90 +4195,76 @@ void ArgumentsAccessStub::GenerateNewNonStrictSlow(MacroAssembler* masm) {
   // of the arguments object and the elements array in words.
   Label add_arguments_object;
   __ bind(&try_allocate);
-  if (type_ == NEW_NON_STRICT_SLOW || type_ == NEW_NON_STRICT_FAST) {
-    __ TailCallRuntime(Runtime::kNewArgumentsFast, 3, 1);
-  } else {
-    __ cmp(r1, Operand(0, RelocInfo::NONE));
-    __ b(eq, &add_arguments_object);
-    __ mov(r1, Operand(r1, LSR, kSmiTagSize));
-    __ add(r1, r1, Operand(FixedArray::kHeaderSize / kPointerSize));
-    __ bind(&add_arguments_object);
-    __ add(r1, r1, Operand(Heap::kArgumentsObjectSizeStrict / kPointerSize));
-
-    // Do the allocation of both objects in one go.
-    __ AllocateInNewSpace(
-        r1,
-        r0,
-        r2,
-        r3,
-        &runtime,
-        static_cast<AllocationFlags>(TAG_OBJECT | SIZE_IN_WORDS));
-
-    // Get the arguments boilerplate from the current (global) context.
-    __ ldr(r4, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
-    __ ldr(r4, FieldMemOperand(r4, GlobalObject::kGlobalContextOffset));
-    __ ldr(r4, MemOperand(r4, Context::SlotOffset(
-        Context::STRICT_MODE_ARGUMENTS_BOILERPLATE_INDEX)));
-
-    // Copy the JS object part.
-    __ CopyFields(r0, r4, r3.bit(), JSObject::kHeaderSize / kPointerSize);
-
-    if (type_ == NEW_NON_STRICT_SLOW || type_ == NEW_NON_STRICT_FAST) {
-      // Setup the callee in-object property.
-      STATIC_ASSERT(Heap::kArgumentsCalleeIndex == 1);
-      __ ldr(r3, MemOperand(sp, 2 * kPointerSize));
-      const int kCalleeOffset = JSObject::kHeaderSize +
-          Heap::kArgumentsCalleeIndex * kPointerSize;
-      __ str(r3, FieldMemOperand(r0, kCalleeOffset));
-    }
-
-    // Get the length (smi tagged) and set that as an in-object property too.
-    STATIC_ASSERT(Heap::kArgumentsLengthIndex == 0);
-    __ ldr(r1, MemOperand(sp, 0 * kPointerSize));
-    __ str(r1, FieldMemOperand(r0, JSObject::kHeaderSize +
-                               Heap::kArgumentsLengthIndex * kPointerSize));
+  __ cmp(r1, Operand(0, RelocInfo::NONE));
+  __ b(eq, &add_arguments_object);
+  __ mov(r1, Operand(r1, LSR, kSmiTagSize));
+  __ add(r1, r1, Operand(FixedArray::kHeaderSize / kPointerSize));
+  __ bind(&add_arguments_object);
+  __ add(r1, r1, Operand(Heap::kArgumentsObjectSizeStrict / kPointerSize));
+
+  // Do the allocation of both objects in one go.
+  __ AllocateInNewSpace(r1,
+                        r0,
+                        r2,
+                        r3,
+                        &runtime,
+                        static_cast<AllocationFlags>(TAG_OBJECT | SIZE_IN_WORDS));
+
+  // Get the arguments boilerplate from the current (global) context.
+  __ ldr(r4, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ ldr(r4, FieldMemOperand(r4, GlobalObject::kGlobalContextOffset));
+  __ ldr(r4, MemOperand(r4, Context::SlotOffset(
+      Context::STRICT_MODE_ARGUMENTS_BOILERPLATE_INDEX)));
+
+  // Copy the JS object part.
+  __ CopyFields(r0, r4, r3.bit(), JSObject::kHeaderSize / kPointerSize);
+
+  // Get the length (smi tagged) and set that as an in-object property too.
+  STATIC_ASSERT(Heap::kArgumentsLengthIndex == 0);
+  __ ldr(r1, MemOperand(sp, 0 * kPointerSize));
+  __ str(r1, FieldMemOperand(r0, JSObject::kHeaderSize +
+      Heap::kArgumentsLengthIndex * kPointerSize));
+
+  // If there are no actual arguments, we're done.
+  Label done;
+  __ cmp(r1, Operand(0, RelocInfo::NONE));
+  __ b(eq, &done);
 
-    // If there are no actual arguments, we're done.
-    Label done;
-    __ cmp(r1, Operand(0, RelocInfo::NONE));
-    __ b(eq, &done);
+  // Get the parameters pointer from the stack.
+  __ ldr(r2, MemOperand(sp, 1 * kPointerSize));
 
-    // Get the parameters pointer from the stack.
-    __ ldr(r2, MemOperand(sp, 1 * kPointerSize));
+  // Setup the elements pointer in the allocated arguments object and
+  // initialize the header in the elements fixed array.
+  __ add(r4, r0, Operand(Heap::kArgumentsObjectSizeStrict));
+  __ str(r4, FieldMemOperand(r0, JSObject::kElementsOffset));
+  __ LoadRoot(r3, Heap::kFixedArrayMapRootIndex);
+  __ str(r3, FieldMemOperand(r4, FixedArray::kMapOffset));
+  __ str(r1, FieldMemOperand(r4, FixedArray::kLengthOffset));
+  // Untag the length for the loop.
+  __ mov(r1, Operand(r1, LSR, kSmiTagSize));
 
-    // Setup the elements pointer in the allocated arguments object and
-    // initialize the header in the elements fixed array.
-    __ add(r4, r0, Operand(Heap::kArgumentsObjectSizeStrict));
-    __ str(r4, FieldMemOperand(r0, JSObject::kElementsOffset));
-    __ LoadRoot(r3, Heap::kFixedArrayMapRootIndex);
-    __ str(r3, FieldMemOperand(r4, FixedArray::kMapOffset));
-    __ str(r1, FieldMemOperand(r4, FixedArray::kLengthOffset));
-    // Untag the length for the loop.
-    __ mov(r1, Operand(r1, LSR, kSmiTagSize));
+  // Copy the fixed array slots.
+  Label loop;
+  // Setup r4 to point to the first array slot.
+  __ add(r4, r4, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
+  __ bind(&loop);
+  // Pre-decrement r2 with kPointerSize on each iteration.
+  // Pre-decrement in order to skip receiver.
+  __ ldr(r3, MemOperand(r2, kPointerSize, NegPreIndex));
+  // Post-increment r4 with kPointerSize on each iteration.
+  __ str(r3, MemOperand(r4, kPointerSize, PostIndex));
+  __ sub(r1, r1, Operand(1));
+  __ cmp(r1, Operand(0, RelocInfo::NONE));
+  __ b(ne, &loop);
 
-    // Copy the fixed array slots.
-    Label loop;
-    // Setup r4 to point to the first array slot.
-    __ add(r4, r4, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
-    __ bind(&loop);
-    // Pre-decrement r2 with kPointerSize on each iteration.
-    // Pre-decrement in order to skip receiver.
-    __ ldr(r3, MemOperand(r2, kPointerSize, NegPreIndex));
-    // Post-increment r4 with kPointerSize on each iteration.
-    __ str(r3, MemOperand(r4, kPointerSize, PostIndex));
-    __ sub(r1, r1, Operand(1));
-    __ cmp(r1, Operand(0, RelocInfo::NONE));
-    __ b(ne, &loop);
-
-    // Return and remove the on-stack parameters.
-    __ bind(&done);
-    __ add(sp, sp, Operand(3 * kPointerSize));
-    __ Ret();
+  // Return and remove the on-stack parameters.
+  __ bind(&done);
+  __ add(sp, sp, Operand(3 * kPointerSize));
+  __ Ret();
 
-    // Do the runtime call to allocate the arguments object.
-    __ bind(&runtime);
-    __ TailCallRuntime(Runtime::kNewStrictArgumentsFast, 3, 1);
-  }
+  // Do the runtime call to allocate the arguments object.
+  __ bind(&runtime);
+  __ TailCallRuntime(Runtime::kNewStrictArgumentsFast, 3, 1);
 }