Fix/unify root handling in code generation.

src/ia32/macro-assembler-ia32.cc

 // Copyright 2012 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 36 matching lines @@
       generating_stub_(false),
       allow_stub_calls_(true),
       has_frame_(false) {
   if (isolate() != NULL) {
     code_object_ = Handle<Object>(isolate()->heap()->undefined_value(),
                                   isolate());
   }
 }
 
 
+void MacroAssembler::LoadRoot(Register destination, Heap::RootListIndex index) {
+  if (isolate()->heap()->RootCanBeTreatedAsConstant(index)) {
+    Handle<Object> value(&isolate()->heap()->roots_array_start()[index]);
+    mov(destination, value);
+    return;
+  }
+  ExternalReference roots_array_start =
+      ExternalReference::roots_array_start(isolate());
+  mov(destination, Immediate(index));
+  mov(destination, Operand::StaticArray(destination,
+                                        times_pointer_size,
+                                        roots_array_start));

[danno, 2013/08/09 13:36:03]

The two moves all be done in one instruction, you might have to add other
infrastructure for that but I would hate to make this code sequence so long if
you are cleaning . Comment holds for instances below, too.

If you do that, you probably don't need a scratch register, either.

[Benedikt Meurer, 2013/08/09 13:41:55]

There's no way to do this in one instruction, cause it would break
serialization.

+}
+
+
+void MacroAssembler::StoreRoot(Register source,
+                               Register scratch,
+                               Heap::RootListIndex index) {
+  ASSERT(Heap::RootCanBeWrittenAfterInitialization(index));
+  ExternalReference roots_array_start =
+      ExternalReference::roots_array_start(isolate());
+  mov(scratch, Immediate(index));
+  mov(Operand::StaticArray(scratch, times_pointer_size, roots_array_start),
+      source);
+}
+
+
+void MacroAssembler::CompareRoot(Register with,
+                                 Register scratch,
+                                 Heap::RootListIndex index) {
+  ExternalReference roots_array_start =
+      ExternalReference::roots_array_start(isolate());
+  mov(scratch, Immediate(index));
+  cmp(with, Operand::StaticArray(scratch,
+                                times_pointer_size,
+                                roots_array_start));
+}
+
+
+void MacroAssembler::CompareRoot(Register with, Heap::RootListIndex index) {
+  ASSERT(isolate()->heap()->RootCanBeTreatedAsConstant(index));
+  Handle<Object> value(&isolate()->heap()->roots_array_start()[index]);
+  cmp(with, value);
+}
+
+
+void MacroAssembler::CompareRoot(const Operand& with,
+                                 Heap::RootListIndex index) {
+  ASSERT(isolate()->heap()->RootCanBeTreatedAsConstant(index));
+  Handle<Object> value(&isolate()->heap()->roots_array_start()[index]);
+  cmp(with, value);
+}
+
+
 void MacroAssembler::InNewSpace(
     Register object,
     Register scratch,
     Condition cc,
     Label* condition_met,
     Label::Distance condition_met_distance) {
   ASSERT(cc == equal || cc == not_equal);
   if (scratch.is(object)) {
     and_(scratch, Immediate(~Page::kPageAlignmentMask));
   } else {
@@ skipping 358 matching lines @@
 void MacroAssembler::SafePush(const Immediate& x) {
   if (IsUnsafeImmediate(x) && jit_cookie() != 0) {
     push(Immediate(x.x_ ^ jit_cookie()));
     xor_(Operand(esp, 0), Immediate(jit_cookie()));
   } else {
     push(x);
   }
 }
 
 
-void MacroAssembler::CompareRoot(Register with, Heap::RootListIndex index) {
-  // see ROOT_ACCESSOR macro in factory.h
-  Handle<Object> value(&isolate()->heap()->roots_array_start()[index]);
-  cmp(with, value);
-}
-
-
-void MacroAssembler::CompareRoot(const Operand& with,
-                                 Heap::RootListIndex index) {
-  // see ROOT_ACCESSOR macro in factory.h
-  Handle<Object> value(&isolate()->heap()->roots_array_start()[index]);
-  cmp(with, value);
-}
-
-
 void MacroAssembler::CmpObjectType(Register heap_object,
                                    InstanceType type,
                                    Register map) {
   mov(map, FieldOperand(heap_object, HeapObject::kMapOffset));
   CmpInstanceType(map, type);
 }
 
 
 void MacroAssembler::CmpInstanceType(Register map, InstanceType type) {
   cmpb(FieldOperand(map, Map::kInstanceTypeOffset),
@@ skipping 2727 matching lines @@
   j(greater, &no_memento_available);
   cmp(MemOperand(scratch_reg, -AllocationMemento::kSize),
       Immediate(Handle<Map>(isolate()->heap()->allocation_memento_map())));
   bind(&no_memento_available);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32