Second step in allocating objects in generated code on ARM

src/arm/macro-assembler-arm.cc

 // Copyright 2006-2009 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 755 matching lines @@
 
   bind(&same_contexts);
 }
 
 
 void MacroAssembler::AllocateObjectInNewSpace(int object_size,
                                               Register result,
                                               Register scratch1,
                                               Register scratch2,
                                               Label* gc_required,
-                                              bool tag_allocated_object) {
+                                              AllocationFlags flags) {
   ASSERT(!result.is(scratch1));
   ASSERT(!scratch1.is(scratch2));
 
   // Load address of new object into result and allocation top address into
   // scratch1.
   ExternalReference new_space_allocation_top =
       ExternalReference::new_space_allocation_top_address();
   mov(scratch1, Operand(new_space_allocation_top));
-  ldr(result, MemOperand(scratch1));
+  if ((flags & RESULT_CONTAINS_TOP) == 0) {
+    ldr(result, MemOperand(scratch1));
+  } else {
+#ifdef DEBUG
+    // Assert that result actually contains top on entry. scratch2 is used
+    // immediately below so this use of scratch2 does not cause difference with
+    // respect to register content between debug and release mode.
+    ldr(scratch2, MemOperand(scratch1));
+    cmp(result, scratch2);
+    Check(eq, "Unexpected allocation top");
+#endif
+  }
 
   // Calculate new top and bail out if new space is exhausted. Use result
   // to calculate the new top.
   ExternalReference new_space_allocation_limit =
       ExternalReference::new_space_allocation_limit_address();
   mov(scratch2, Operand(new_space_allocation_limit));
   ldr(scratch2, MemOperand(scratch2));
   add(result, result, Operand(object_size * kPointerSize));
   cmp(result, Operand(scratch2));
   b(hi, gc_required);
 
   // Update allocation top. result temporarily holds the new top,
   str(result, MemOperand(scratch1));
 
   // Tag and adjust back to start of new object.
-  if (tag_allocated_object) {
+  if ((flags & TAG_OBJECT) != 0) {
     sub(result, result, Operand((object_size * kPointerSize) -
                                 kHeapObjectTag));
   } else {
     sub(result, result, Operand(object_size * kPointerSize));
   }
 }
 
 
 void MacroAssembler::AllocateObjectInNewSpace(Register object_size,
                                               Register result,
                                               Register scratch1,
                                               Register scratch2,
                                               Label* gc_required,
-                                              bool tag_allocated_object) {
+                                              AllocationFlags flags) {
   ASSERT(!result.is(scratch1));
   ASSERT(!scratch1.is(scratch2));
 
   // Load address of new object into result and allocation top address into
   // scratch1.
   ExternalReference new_space_allocation_top =
       ExternalReference::new_space_allocation_top_address();
   mov(scratch1, Operand(new_space_allocation_top));
-  ldr(result, MemOperand(scratch1));
+  if ((flags & RESULT_CONTAINS_TOP) == 0) {
+    ldr(result, MemOperand(scratch1));
+  } else {
+#ifdef DEBUG
+    // Assert that result actually contains top on entry. scratch2 is used
+    // immediately below so this use of scratch2 does not cause difference with
+    // respect to register content between debug and release mode.
+    ldr(scratch2, MemOperand(scratch1));
+    cmp(result, scratch2);
+    Check(eq, "Unexpected allocation top");
+#endif
+  }
 
   // Calculate new top and bail out if new space is exhausted. Use result
   // to calculate the new top. Object size is in words so a shift is required to
   // get the number of bytes
   ExternalReference new_space_allocation_limit =
       ExternalReference::new_space_allocation_limit_address();
   mov(scratch2, Operand(new_space_allocation_limit));
   ldr(scratch2, MemOperand(scratch2));
   add(result, result, Operand(object_size, LSL, kPointerSizeLog2));
-
   cmp(result, Operand(scratch2));
   b(hi, gc_required);
 
   // Update allocation top. result temporarily holds the new top,
   str(result, MemOperand(scratch1));
 
-  // Tag and adjust back to start of new object.
-  if (tag_allocated_object) {
-    sub(result, result, Operand(object_size, LSL, kPointerSizeLog2));
+  // Adjust back to start of new object.
+  sub(result, result, Operand(object_size, LSL, kPointerSizeLog2));
+
+  // Tag object if requested.
+  if ((flags & TAG_OBJECT) != 0) {
     add(result, result, Operand(kHeapObjectTag));
-  } else {
-    sub(result, result, Operand(object_size, LSL, kPointerSizeLog2));
   }
 }
 
 
 void MacroAssembler::UndoAllocationInNewSpace(Register object,
                                               Register scratch) {
   ExternalReference new_space_allocation_top =
       ExternalReference::new_space_allocation_top_address();
 
   // Make sure the object has no tag before resetting top.
@@ skipping 267 matching lines @@
   mov(r0, Operand(p0));
   push(r0);
   mov(r0, Operand(Smi::FromInt(p1 - p0)));
   push(r0);
   CallRuntime(Runtime::kAbort, 2);
   // will not return here
 }
 
 
 } }  // namespace v8::internal