ARM: Implement code stub for object literal creation.

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 9e6f7596e7fc60131cdaf956d07567854514e74b..f74c124c594bd28444392ffac314bbbbfe8bb51c 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -343,6 +343,50 @@ void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
 }
 
 
+void FastCloneShallowObjectStub::Generate(MacroAssembler* masm) {
+  // Stack layout on entry:
+  //
+  // [sp]: object literal flags.
+  // [sp + kPointerSize]: constant properties.
+  // [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, 3 * kPointerSize));
+  __ ldr(r0, MemOperand(sp, 2 * kPointerSize));
+  __ add(r3, r3, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
+  __ ldr(r3, MemOperand(r3, r0, LSL, kPointerSizeLog2 - kSmiTagSize));
+  __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
+  __ cmp(r3, ip);

[Erik Corry, 2011/11/23 14:14:15]

Seems like you could use CompareRoot here.

[Michael Starzinger, 2011/11/23 15:02:03]

Done.

+  __ b(eq, &slow_case);
+
+  // Check that the boilerplate contains only fast properties and we can
+  // statically determine the instance size.

[Erik Corry, 2011/11/23 14:14:15]

As discussed offline this can be omitted for MOAR speed in the next CL.

+  int size = JSObject::kHeaderSize + length_ * kPointerSize;
+  __ ldr(r0, FieldMemOperand(r3, HeapObject::kMapOffset));
+  __ ldrb(r0, FieldMemOperand(r0, Map::kInstanceSizeOffset));
+  __ cmp(r0, Operand(size >> kPointerSizeLog2));
+  __ b(ne, &slow_case);
+
+  // Allocate the JS object and copy header together with all in-object
+  // properties from the boilerplate.
+  __ AllocateInNewSpace(size, r0, r1, r2, &slow_case, TAG_OBJECT);
+  for (int i = 0; i < size; i += kPointerSize) {
+    __ ldr(r1, FieldMemOperand(r3, i));
+    __ str(r1, FieldMemOperand(r0, i));
+  }
+
+  // Return and remove the on-stack parameters.
+  __ add(sp, sp, Operand(4 * kPointerSize));
+  __ Ret();
+
+  __ bind(&slow_case);
+  __ TailCallRuntime(Runtime::kCreateObjectLiteralShallow, 4, 1);
+}
+
+
 // Takes a Smi and converts to an IEEE 64 bit floating point value in two
 // registers.  The format is 1 sign bit, 11 exponent bits (biased 1023) and
 // 52 fraction bits (20 in the first word, 32 in the second).  Zeros is a