Supporting AllocationSiteInfo for Nested arrays

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 1236e31784c917d87fa612db324303298b191773..3d2515449c45de3e962259befaef57a2148ef5ce 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -410,15 +410,16 @@ static void GenerateFastCloneShallowArrayCommon(
 void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
   // Stack layout on entry:
   //
-  // [sp]: constant elements.
-  // [sp + kPointerSize]: literal index.
-  // [sp + (2 * kPointerSize)]: literals array.
+  // [sp]: flags (ignored)

[danno, 2013/02/08 13:44:38]

I don't think you need to pass flags explicitly. Instead, parameterize the flags
into the MinorKey of the stub, keeping the same calling convention as before.
Create then two versions, one that passes ALLOCATE_SITE_INFO to the tail call
into the runtime, and one that doesn't. At the callee site, you know which
version you need, but you don't have to pay the extra expense of always
pushing/popping the ignored parameter in the fast case. 

[mvstanton, 2013/02/11 11:11:24]

good idea, thanks.

+  // [sp + kPointerSize]: constant elements.
+  // [sp + (2 * kPointerSize)]: literal index.
+  // [sp + (3 * kPointerSize)]: literals array.
 
   // Load boilerplate object into r3 and check if we need to create a
   // boilerplate.
   Label slow_case;
-  __ ldr(r3, MemOperand(sp, 2 * kPointerSize));
-  __ ldr(r0, MemOperand(sp, 1 * kPointerSize));
+  __ ldr(r3, MemOperand(sp, 3 * kPointerSize));
+  __ ldr(r0, MemOperand(sp, 2 * kPointerSize));
   __ add(r3, r3, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
   __ ldr(r3, MemOperand(r3, r0, LSL, kPointerSizeLog2 - kSmiTagSize));
   __ CompareRoot(r3, Heap::kUndefinedValueRootIndex);
@@ -435,7 +436,7 @@ void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
                                         allocation_site_mode_,
                                         &slow_case);
     // Return and remove the on-stack parameters.
-    __ add(sp, sp, Operand(3 * kPointerSize));
+    __ add(sp, sp, Operand(4 * kPointerSize));
     __ Ret();
 
     __ bind(&check_fast_elements);
@@ -445,7 +446,7 @@ void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
                                         allocation_site_mode_,
                                         &slow_case);
     // Return and remove the on-stack parameters.
-    __ add(sp, sp, Operand(3 * kPointerSize));
+    __ add(sp, sp, Operand(4 * kPointerSize));
     __ Ret();
 
     __ bind(&double_elements);
@@ -480,11 +481,11 @@ void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
                                       &slow_case);
 
   // Return and remove the on-stack parameters.
-  __ add(sp, sp, Operand(3 * kPointerSize));
+  __ add(sp, sp, Operand(4 * kPointerSize));
   __ Ret();
 
   __ bind(&slow_case);

[danno, 2013/02/08 13:44:38]

In the parameterized stub, you'd have to push the flags here before calling
through.

[mvstanton, 2013/02/11 11:11:24]

Done.

-  __ TailCallRuntime(Runtime::kCreateArrayLiteralShallow, 3, 1);
+  __ TailCallRuntime(Runtime::kCreateArrayLiteralShallow, 4, 1);
 }