Support for global var shortcuts in script contexts.

src/x64/full-codegen-x64.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_X64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 333 matching lines @@
 
   } else {
     PrepareForBailoutForId(BailoutId::FunctionEntry(), NO_REGISTERS);
     { Comment cmnt(masm_, "[ Declarations");
       // For named function expressions, declare the function name as a
       // constant.
       if (scope()->is_function_scope() && scope()->function() != NULL) {
         VariableDeclaration* function = scope()->function();
         DCHECK(function->proxy()->var()->mode() == CONST ||
                function->proxy()->var()->mode() == CONST_LEGACY);
-        DCHECK(function->proxy()->var()->location() != Variable::UNALLOCATED);
+        DCHECK(!function->proxy()->var()->IsUnallocatedOrGlobalSlot());
         VisitVariableDeclaration(function);
       }
       VisitDeclarations(scope()->declarations());
     }
 
     { Comment cmnt(masm_, "[ Stack check");
       PrepareForBailoutForId(BailoutId::Declarations(), NO_REGISTERS);
        Label ok;
        __ CompareRoot(rsp, Heap::kStackLimitRootIndex);
        __ j(above_equal, &ok, Label::kNear);
@@ skipping 472 matching lines @@
 void FullCodeGenerator::VisitVariableDeclaration(
     VariableDeclaration* declaration) {
   // If it was not possible to allocate the variable at compile time, we
   // need to "declare" it at runtime to make sure it actually exists in the
   // local context.
   VariableProxy* proxy = declaration->proxy();
   VariableMode mode = declaration->mode();
   Variable* variable = proxy->var();
   bool hole_init = mode == LET || mode == CONST || mode == CONST_LEGACY;
   switch (variable->location()) {
-    case Variable::UNALLOCATED:
+    case VariableLocation::GLOBAL:
+    case VariableLocation::UNALLOCATED:
       globals_->Add(variable->name(), zone());
       globals_->Add(variable->binding_needs_init()
                         ? isolate()->factory()->the_hole_value()
                     : isolate()->factory()->undefined_value(),
                     zone());
       break;
 
-    case Variable::PARAMETER:
-    case Variable::LOCAL:
+    case VariableLocation::PARAMETER:
+    case VariableLocation::LOCAL:
       if (hole_init) {
         Comment cmnt(masm_, "[ VariableDeclaration");
         __ LoadRoot(kScratchRegister, Heap::kTheHoleValueRootIndex);
         __ movp(StackOperand(variable), kScratchRegister);
       }
       break;
 
-    case Variable::CONTEXT:
+    case VariableLocation::CONTEXT:
       if (hole_init) {
         Comment cmnt(masm_, "[ VariableDeclaration");
         EmitDebugCheckDeclarationContext(variable);
         __ LoadRoot(kScratchRegister, Heap::kTheHoleValueRootIndex);
         __ movp(ContextOperand(rsi, variable->index()), kScratchRegister);
         // No write barrier since the hole value is in old space.
         PrepareForBailoutForId(proxy->id(), NO_REGISTERS);
       }
       break;
 
-    case Variable::LOOKUP: {
+    case VariableLocation::LOOKUP: {
       Comment cmnt(masm_, "[ VariableDeclaration");
       __ Push(rsi);
       __ Push(variable->name());
       // Declaration nodes are always introduced in one of four modes.
       DCHECK(IsDeclaredVariableMode(mode));
       PropertyAttributes attr =
           IsImmutableVariableMode(mode) ? READ_ONLY : NONE;
       __ Push(Smi::FromInt(attr));
       // Push initial value, if any.
       // Note: For variables we must not push an initial value (such as
       // 'undefined') because we may have a (legal) redeclaration and we
       // must not destroy the current value.
       if (hole_init) {
         __ PushRoot(Heap::kTheHoleValueRootIndex);
       } else {
         __ Push(Smi::FromInt(0));  // Indicates no initial value.
       }
       __ CallRuntime(Runtime::kDeclareLookupSlot, 4);
       break;
     }
   }
 }
 
 
 void FullCodeGenerator::VisitFunctionDeclaration(
     FunctionDeclaration* declaration) {
   VariableProxy* proxy = declaration->proxy();
   Variable* variable = proxy->var();
   switch (variable->location()) {
-    case Variable::UNALLOCATED: {
+    case VariableLocation::GLOBAL:
+    case VariableLocation::UNALLOCATED: {
       globals_->Add(variable->name(), zone());
       Handle<SharedFunctionInfo> function =
           Compiler::GetSharedFunctionInfo(declaration->fun(), script(), info_);
       // Check for stack-overflow exception.
       if (function.is_null()) return SetStackOverflow();
       globals_->Add(function, zone());
       break;
     }
 
-    case Variable::PARAMETER:
-    case Variable::LOCAL: {
+    case VariableLocation::PARAMETER:
+    case VariableLocation::LOCAL: {
       Comment cmnt(masm_, "[ FunctionDeclaration");
       VisitForAccumulatorValue(declaration->fun());
       __ movp(StackOperand(variable), result_register());
       break;
     }
 
-    case Variable::CONTEXT: {
+    case VariableLocation::CONTEXT: {
       Comment cmnt(masm_, "[ FunctionDeclaration");
       EmitDebugCheckDeclarationContext(variable);
       VisitForAccumulatorValue(declaration->fun());
       __ movp(ContextOperand(rsi, variable->index()), result_register());
       int offset = Context::SlotOffset(variable->index());
       // We know that we have written a function, which is not a smi.
       __ RecordWriteContextSlot(rsi,
                                 offset,
                                 result_register(),
                                 rcx,
                                 kDontSaveFPRegs,
                                 EMIT_REMEMBERED_SET,
                                 OMIT_SMI_CHECK);
       PrepareForBailoutForId(proxy->id(), NO_REGISTERS);
       break;
     }
 
-    case Variable::LOOKUP: {
+    case VariableLocation::LOOKUP: {
       Comment cmnt(masm_, "[ FunctionDeclaration");
       __ Push(rsi);
       __ Push(variable->name());
       __ Push(Smi::FromInt(NONE));
       VisitForStackValue(declaration->fun());
       __ CallRuntime(Runtime::kDeclareLookupSlot, 4);
       break;
     }
   }
 }
 
 
 void FullCodeGenerator::VisitImportDeclaration(ImportDeclaration* declaration) {
   VariableProxy* proxy = declaration->proxy();
   Variable* variable = proxy->var();
   switch (variable->location()) {
-    case Variable::UNALLOCATED:
+    case VariableLocation::UNALLOCATED:
+    case VariableLocation::GLOBAL:
       // TODO(rossberg)
       break;
 
-    case Variable::CONTEXT: {
+    case VariableLocation::CONTEXT: {
       Comment cmnt(masm_, "[ ImportDeclaration");
       EmitDebugCheckDeclarationContext(variable);
       // TODO(rossberg)
       break;
     }
 
-    case Variable::PARAMETER:
-    case Variable::LOCAL:
-    case Variable::LOOKUP:
+    case VariableLocation::PARAMETER:
+    case VariableLocation::LOCAL:
+    case VariableLocation::LOOKUP:
       UNREACHABLE();
   }
 }
 
 
 void FullCodeGenerator::VisitExportDeclaration(ExportDeclaration* declaration) {
   // TODO(rossberg)
 }
 
 
@@ skipping 474 matching lines @@
 
 void FullCodeGenerator::EmitVariableLoad(VariableProxy* proxy) {
   // Record position before possible IC call.
   SetExpressionPosition(proxy);
   PrepareForBailoutForId(proxy->BeforeId(), NO_REGISTERS);
   Variable* var = proxy->var();
 
   // Three cases: global variables, lookup variables, and all other types of
   // variables.
   switch (var->location()) {
-    case Variable::UNALLOCATED: {
+    case VariableLocation::GLOBAL:
+    case VariableLocation::UNALLOCATED: {
       Comment cmnt(masm_, "[ Global variable");
       __ Move(LoadDescriptor::NameRegister(), var->name());
       __ movp(LoadDescriptor::ReceiverRegister(), GlobalObjectOperand());
       __ Move(LoadDescriptor::SlotRegister(),
               SmiFromSlot(proxy->VariableFeedbackSlot()));
       CallGlobalLoadIC(var->name());
       context()->Plug(rax);
       break;
     }
 
-    case Variable::PARAMETER:
-    case Variable::LOCAL:
-    case Variable::CONTEXT: {
+    case VariableLocation::PARAMETER:
+    case VariableLocation::LOCAL:
+    case VariableLocation::CONTEXT: {
       Comment cmnt(masm_, var->IsContextSlot() ? "[ Context slot"
                                                : "[ Stack slot");
       if (var->binding_needs_init()) {
         // var->scope() may be NULL when the proxy is located in eval code and
         // refers to a potential outside binding. Currently those bindings are
         // always looked up dynamically, i.e. in that case
         //     var->location() == LOOKUP.
         // always holds.
         DCHECK(var->scope() != NULL);
 
@@ skipping 47 matching lines @@
           }
           __ bind(&done);
           context()->Plug(rax);
           break;
         }
       }
       context()->Plug(var);
       break;
     }
 
-    case Variable::LOOKUP: {
+    case VariableLocation::LOOKUP: {
       Comment cmnt(masm_, "[ Lookup slot");
       Label done, slow;
       // Generate code for loading from variables potentially shadowed
       // by eval-introduced variables.
       EmitDynamicLookupFastCase(proxy, NOT_INSIDE_TYPEOF, &slow, &done);
       __ bind(&slow);
       __ Push(rsi);  // Context.
       __ Push(var->name());
       __ CallRuntime(Runtime::kLoadLookupSlot, 2);
       __ bind(&done);
@@ skipping 1081 matching lines @@
   if (var->IsContextSlot()) {
     __ movp(rdx, rax);
     __ RecordWriteContextSlot(
         rcx, Context::SlotOffset(var->index()), rdx, rbx, kDontSaveFPRegs);
   }
 }
 
 
 void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
                                                FeedbackVectorICSlot slot) {
-  if (var->IsUnallocated()) {
+  if (var->IsUnallocatedOrGlobalSlot()) {
     // Global var, const, or let.
     __ Move(StoreDescriptor::NameRegister(), var->name());
     __ movp(StoreDescriptor::ReceiverRegister(), GlobalObjectOperand());
     if (FLAG_vector_stores) EmitLoadStoreICSlot(slot);
     CallStoreIC();
 
   } 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());
@@ skipping 2086 matching lines @@
         VisitForStackValue(property->key());
         __ Push(Smi::FromInt(language_mode()));
         __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
         context()->Plug(rax);
       } else if (proxy != NULL) {
         Variable* var = proxy->var();
         // Delete of an unqualified identifier is disallowed in strict mode but
         // "delete this" is allowed.
         bool is_this = var->HasThisName(isolate());
         DCHECK(is_sloppy(language_mode()) || is_this);
-        if (var->IsUnallocated()) {
+        if (var->IsUnallocatedOrGlobalSlot()) {
           __ Push(GlobalObjectOperand());
           __ Push(var->name());
           __ Push(Smi::FromInt(SLOPPY));
           __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
           context()->Plug(rax);
         } else if (var->IsStackAllocated() || var->IsContextSlot()) {
           // Result of deleting non-global variables is false.  'this' is
           // not really a variable, though we implement it as one.  The
           // subexpression does not have side effects.
           context()->Plug(is_this);
@@ skipping 339 matching lines @@
     }
   }
 }
 
 
 void FullCodeGenerator::VisitForTypeofValue(Expression* expr) {
   VariableProxy* proxy = expr->AsVariableProxy();
   DCHECK(!context()->IsEffect());
   DCHECK(!context()->IsTest());
 
-  if (proxy != NULL && proxy->var()->IsUnallocated()) {
+  if (proxy != NULL && proxy->var()->IsUnallocatedOrGlobalSlot()) {
     Comment cmnt(masm_, "[ Global variable");
     __ Move(LoadDescriptor::NameRegister(), proxy->name());
     __ movp(LoadDescriptor::ReceiverRegister(), GlobalObjectOperand());
     __ Move(LoadDescriptor::SlotRegister(),
             SmiFromSlot(proxy->VariableFeedbackSlot()));
     // Use a regular load, not a contextual load, to avoid a reference
     // error.
     CallLoadIC(NOT_CONTEXTUAL);
     PrepareForBailout(expr, TOS_REG);
     context()->Plug(rax);
@@ skipping 382 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64