* String type inference using compiler framework.

src/virtual-frame.cc

 // Copyright 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 75 matching lines @@
     case FrameElement::COPY:
       // We do not allow copies of copies, so we follow one link to
       // the actual backing store of a copy before making a copy.
       index = target.index();
       ASSERT(elements_[index].is_memory() || elements_[index].is_register());
       // Fall through.
 
     case FrameElement::MEMORY:  // Fall through.
     case FrameElement::REGISTER:
       // All copies are backed by memory or register locations.
-      result.type_ =
-          FrameElement::TypeField::encode(FrameElement::COPY)
-          | FrameElement::IsCopiedField::encode(false)
-          | FrameElement::SyncField::encode(FrameElement::NOT_SYNCED);
+      result.set_static_type(target.static_type());
+      result.type_ = FrameElement::COPY;
+      result.copied_ = false;
+      result.synced_ = false;
       result.data_.index_ = index;
       elements_[index].set_copied();
       break;
 
     case FrameElement::INVALID:
       // We should not try to copy invalid elements.
       UNREACHABLE();
       break;
   }
   return result;
@@ skipping 91 matching lines @@
 
   SyncElementAt(index);
   // The element is now in memory.  Its copied flag is preserved.
   FrameElement new_element = FrameElement::MemoryElement();
   if (elements_[index].is_copied()) {
     new_element.set_copied();
   }
   if (elements_[index].is_register()) {
     Unuse(elements_[index].reg());
   }
+  new_element.set_static_type(elements_[index].static_type());
   elements_[index] = new_element;
 }
 
 
 // Clear the dirty bits for the range of elements in
 // [min(stack_pointer_ + 1,begin), end).
 void VirtualFrame::SyncRange(int begin, int end) {
   ASSERT(begin >= 0);
   ASSERT(end <= elements_.length());
   if (begin > stack_pointer_) {
@@ skipping 160 matching lines @@
 
   InvalidateFrameSlotAt(frame_index);
 
   FrameElement new_element;
   if (value->is_register()) {
     if (is_used(value->reg())) {
       // The register already appears on the frame.  Either the existing
       // register element, or the new element at frame_index, must be made
       // a copy.
       int i = register_index(value->reg());
+      ASSERT(value->static_type() == elements_[i].static_type());
+
       if (i < frame_index) {
         // The register FrameElement is lower in the frame than the new copy.
         elements_[frame_index] = CopyElementAt(i);
       } else {
         // There was an early bailout for the case of setting a
         // register element to itself.
         ASSERT(i != frame_index);
         elements_[frame_index] = elements_[i];
         elements_[i] = CopyElementAt(frame_index);
         if (elements_[frame_index].is_synced()) {
           elements_[i].set_sync();
         }
         elements_[frame_index].clear_sync();
         register_locations_[value->reg().code()] = frame_index;
         for (int j = i + 1; j < elements_.length(); j++) {
           if (elements_[j].is_copy() && elements_[j].index() == i) {
             elements_[j].set_index(frame_index);
           }
         }
       }
     } else {
       // The register value->reg() was not already used on the frame.
       Use(value->reg(), frame_index);
       elements_[frame_index] =
           FrameElement::RegisterElement(value->reg(),
-                                        FrameElement::NOT_SYNCED);
+                                        FrameElement::NOT_SYNCED,
+                                        value->static_type());
     }
   } else {
     ASSERT(value->is_constant());
     elements_[frame_index] =
         FrameElement::ConstantElement(value->handle(),
                                       FrameElement::NOT_SYNCED);
   }
   value->Unuse();
 }
 
 
 void VirtualFrame::PushFrameSlotAt(int index) {
   FrameElement new_element = CopyElementAt(index);
   elements_.Add(new_element);
 }
 
 
 Result VirtualFrame::CallStub(CodeStub* stub, int arg_count) {
   PrepareForCall(arg_count, arg_count);
   return RawCallStub(stub);
 }
 
 
-void VirtualFrame::Push(Register reg) {
+void VirtualFrame::Push(Register reg, StaticType static_type) {
   if (is_used(reg)) {
-    elements_.Add(CopyElementAt(register_index(reg)));
+    int index = register_index(reg);
+    FrameElement element = CopyElementAt(index);
+    ASSERT(static_type.merge(element.static_type()) == element.static_type());
+    elements_.Add(element);
   } else {
     Use(reg, elements_.length());
-    elements_.Add(FrameElement::RegisterElement(reg, FrameElement::NOT_SYNCED));
+    FrameElement element =
+        FrameElement::RegisterElement(reg,
+                                      FrameElement::NOT_SYNCED,
+                                      static_type);
+    elements_.Add(element);
   }
 }
 
 
 void VirtualFrame::Push(Handle<Object> value) {
-  elements_.Add(FrameElement::ConstantElement(value,
-                                              FrameElement::NOT_SYNCED));
+  FrameElement element =
+      FrameElement::ConstantElement(value, FrameElement::NOT_SYNCED);
+  elements_.Add(element);
 }
 
 
 void VirtualFrame::Push(Result* result) {
   if (result->is_register()) {
-    Push(result->reg());
+    Push(result->reg(), result->static_type());
   } else {
     ASSERT(result->is_constant());
     Push(result->handle());
   }
   result->Unuse();
 }
 
 
 void VirtualFrame::Nip(int num_dropped) {
   ASSERT(num_dropped >= 0);
   if (num_dropped == 0) return;
   Result tos = Pop();
   if (num_dropped > 1) {
     Drop(num_dropped - 1);
   }
   SetElementAt(0, &tos);
 }
 
 
 bool FrameElement::Equals(FrameElement other) {
-  if (type_ != other.type_) return false;
+  if (type_ != other.type_ ||
+      copied_ != other.copied_ ||
+      synced_ != other.synced_) return false;
 
   if (is_register()) {
     if (!reg().is(other.reg())) return false;
   } else if (is_constant()) {
     if (!handle().is_identical_to(other.handle())) return false;
   } else if (is_copy()) {
     if (index() != other.index()) return false;
   }
 
   return true;
@@ skipping 19 matching lines @@
 #endif
   if (stack_pointer_ != other->stack_pointer_) return false;
   for (int i = 0; i < elements_.length(); i++) {
     if (!elements_[i].Equals(other->elements_[i])) return false;
   }
 
   return true;
 }
 
 } }  // namespace v8::internal