Loads and stores to global vars are now made via property cell shortcuts installed into parent scri…

src/mips/full-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_MIPS
 
 // Note on Mips implementation:
 //
@@ skipping 1466 matching lines @@
     __ Branch(done);
   }
 }
 
 
 void FullCodeGenerator::EmitGlobalVariableLoad(VariableProxy* proxy,
                                                TypeofState typeof_state) {
   Variable* var = proxy->var();
   DCHECK(var->IsUnallocatedOrGlobalSlot() ||
          (var->IsLookupSlot() && var->mode() == DYNAMIC_GLOBAL));
-  __ lw(LoadDescriptor::ReceiverRegister(), GlobalObjectOperand());
-  __ li(LoadDescriptor::NameRegister(), Operand(var->name()));
-  __ li(LoadDescriptor::SlotRegister(),
-        Operand(SmiFromSlot(proxy->VariableFeedbackSlot())));
-  // Inside typeof use a regular load, not a contextual load, to avoid
-  // a reference error.
-  CallLoadIC(typeof_state == NOT_INSIDE_TYPEOF ? CONTEXTUAL : NOT_CONTEXTUAL);
+  if (var->IsGlobalSlot()) {
+    DCHECK(var->index() > 0);
+    DCHECK(var->IsStaticGlobalObjectProperty());
+    // Each var occupies two slots in the context: for reads and writes.
+    int slot_index = var->index();
+    int depth = scope()->ContextChainLength(var->scope());
+    __ li(LoadGlobalViaContextDescriptor::DepthRegister(),
+          Operand(Smi::FromInt(depth)));
+    __ li(LoadGlobalViaContextDescriptor::SlotRegister(),
+          Operand(Smi::FromInt(slot_index)));
+    __ li(LoadGlobalViaContextDescriptor::NameRegister(), Operand(var->name()));
+    LoadGlobalViaContextStub stub(isolate(), depth);
+    __ CallStub(&stub);
+
+  } else {
+    __ lw(LoadDescriptor::ReceiverRegister(), GlobalObjectOperand());
+    __ li(LoadDescriptor::NameRegister(), Operand(var->name()));
+    __ li(LoadDescriptor::SlotRegister(),
+          Operand(SmiFromSlot(proxy->VariableFeedbackSlot())));
+    // Inside typeof use a regular load, not a contextual load, to avoid
+    // a reference error.
+    CallLoadIC(typeof_state == NOT_INSIDE_TYPEOF ? CONTEXTUAL : NOT_CONTEXTUAL);
+  }
 }
 
 
 void FullCodeGenerator::EmitVariableLoad(VariableProxy* proxy,
                                          TypeofState typeof_state) {
   // Record position before possible IC call.
   SetExpressionPosition(proxy);
   PrepareForBailoutForId(proxy->BeforeId(), NO_REGISTERS);
   Variable* var = proxy->var();
 
@@ skipping 1228 matching lines @@
     __ Move(a3, result_register());
     int offset = Context::SlotOffset(var->index());
     __ RecordWriteContextSlot(
         a1, offset, a3, a2, kRAHasBeenSaved, kDontSaveFPRegs);
   }
 }
 
 
 void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
                                                FeedbackVectorICSlot slot) {
-  if (var->IsUnallocatedOrGlobalSlot()) {
+  if (var->IsUnallocated()) {
     // Global var, const, or let.
     __ mov(StoreDescriptor::ValueRegister(), result_register());
     __ li(StoreDescriptor::NameRegister(), Operand(var->name()));
     __ lw(StoreDescriptor::ReceiverRegister(), GlobalObjectOperand());
     if (FLAG_vector_stores) EmitLoadStoreICSlot(slot);
     CallStoreIC();
 
+  } else if (var->IsGlobalSlot()) {
+    // Global var, const, or let.
+    DCHECK(var->index() > 0);
+    DCHECK(var->IsStaticGlobalObjectProperty());
+    // Each var occupies two slots in the context: for reads and writes.
+    int slot_index = var->index() + 1;
+    int depth = scope()->ContextChainLength(var->scope());
+    __ li(StoreGlobalViaContextDescriptor::DepthRegister(),
+          Operand(Smi::FromInt(depth)));
+    __ li(StoreGlobalViaContextDescriptor::SlotRegister(),
+          Operand(Smi::FromInt(slot_index)));
+    __ li(StoreGlobalViaContextDescriptor::NameRegister(),
+          Operand(var->name()));
+    __ mov(StoreGlobalViaContextDescriptor::ValueRegister(), result_register());
+    StoreGlobalViaContextStub stub(isolate(), depth, language_mode());
+    __ CallStub(&stub);
+
   } else if (var->mode() == LET && op != Token::INIT_LET) {
     // Non-initializing assignment to let variable needs a write barrier.
     DCHECK(!var->IsLookupSlot());
     DCHECK(var->IsStackAllocated() || var->IsContextSlot());
     Label assign;
     MemOperand location = VarOperand(var, a1);
     __ lw(a3, location);
     __ LoadRoot(t0, Heap::kTheHoleValueRootIndex);
     __ Branch(&assign, ne, a3, Operand(t0));
     __ li(a3, Operand(var->name()));
@@ skipping 2790 matching lines @@
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OsrAfterStackCheck()->entry()));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS