Remove %_SwapElements. This inlined runtime contained an optimization that was dangerous in the pr…

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
===================================================================
--- src/arm/full-codegen-arm.cc	(revision 11587)
+++ src/arm/full-codegen-arm.cc	(working copy)
@@ -3466,104 +3466,6 @@
 }
 
 
-void FullCodeGenerator::EmitSwapElements(CallRuntime* expr) {
-  ZoneList<Expression*>* args = expr->arguments();
-  ASSERT(args->length() == 3);
-  VisitForStackValue(args->at(0));
-  VisitForStackValue(args->at(1));
-  VisitForStackValue(args->at(2));
-  Label done;
-  Label slow_case;
-  Register object = r0;
-  Register index1 = r1;
-  Register index2 = r2;
-  Register elements = r3;
-  Register scratch1 = r4;
-  Register scratch2 = r5;
-
-  __ ldr(object, MemOperand(sp, 2 * kPointerSize));
-  // Fetch the map and check if array is in fast case.
-  // Check that object doesn't require security checks and
-  // has no indexed interceptor.
-  __ CompareObjectType(object, scratch1, scratch2, JS_ARRAY_TYPE);
-  __ b(ne, &slow_case);
-  // Map is now in scratch1.
-
-  __ ldrb(scratch2, FieldMemOperand(scratch1, Map::kBitFieldOffset));
-  __ tst(scratch2, Operand(KeyedLoadIC::kSlowCaseBitFieldMask));
-  __ b(ne, &slow_case);
-
-  // Check the object's elements are in fast case and writable.
-  __ ldr(elements, FieldMemOperand(object, JSObject::kElementsOffset));
-  __ ldr(scratch1, FieldMemOperand(elements, HeapObject::kMapOffset));
-  __ LoadRoot(ip, Heap::kFixedArrayMapRootIndex);
-  __ cmp(scratch1, ip);
-  __ b(ne, &slow_case);
-
-  // Check that both indices are smis.
-  __ ldr(index1, MemOperand(sp, 1 * kPointerSize));
-  __ ldr(index2, MemOperand(sp, 0));
-  __ JumpIfNotBothSmi(index1, index2, &slow_case);
-
-  // Check that both indices are valid.
-  __ ldr(scratch1, FieldMemOperand(object, JSArray::kLengthOffset));
-  __ cmp(scratch1, index1);
-  __ cmp(scratch1, index2, hi);
-  __ b(ls, &slow_case);
-
-  // Bring the address of the elements into index1 and index2.
-  __ add(scratch1, elements, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
-  __ add(index1,
-         scratch1,
-         Operand(index1, LSL, kPointerSizeLog2 - kSmiTagSize));
-  __ add(index2,
-         scratch1,
-         Operand(index2, LSL, kPointerSizeLog2 - kSmiTagSize));
-
-  // Swap elements.
-  __ ldr(scratch1, MemOperand(index1, 0));
-  __ ldr(scratch2, MemOperand(index2, 0));
-  __ str(scratch1, MemOperand(index2, 0));
-  __ str(scratch2, MemOperand(index1, 0));
-
-  Label no_remembered_set;
-  __ CheckPageFlag(elements,
-                   scratch1,
-                   1 << MemoryChunk::SCAN_ON_SCAVENGE,
-                   ne,
-                   &no_remembered_set);
-  // Possible optimization: do a check that both values are Smis
-  // (or them and test against Smi mask.)
-
-  // We are swapping two objects in an array and the incremental marker never
-  // pauses in the middle of scanning a single object.  Therefore the
-  // incremental marker is not disturbed, so we don't need to call the
-  // RecordWrite stub that notifies the incremental marker.
-  __ RememberedSetHelper(elements,
-                         index1,
-                         scratch2,
-                         kDontSaveFPRegs,
-                         MacroAssembler::kFallThroughAtEnd);
-  __ RememberedSetHelper(elements,
-                         index2,
-                         scratch2,
-                         kDontSaveFPRegs,
-                         MacroAssembler::kFallThroughAtEnd);
-
-  __ bind(&no_remembered_set);
-  // We are done. Drop elements from the stack, and return undefined.
-  __ Drop(3);
-  __ LoadRoot(r0, Heap::kUndefinedValueRootIndex);
-  __ jmp(&done);
-
-  __ bind(&slow_case);
-  __ CallRuntime(Runtime::kSwapElements, 3);
-
-  __ bind(&done);
-  context()->Plug(r0);
-}
-
-
 void FullCodeGenerator::EmitGetFromCache(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   ASSERT_EQ(2, args->length());