Support for global var shortcuts in script contexts.

src/arm64/full-codegen-arm64.cc

 // Copyright 2013 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_ARM64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 336 matching lines @@
     Comment cmnt(masm_, "[ Declarations");
     scope()->VisitIllegalRedeclaration(this);
 
   } else {
     PrepareForBailoutForId(BailoutId::FunctionEntry(), NO_REGISTERS);
     { Comment cmnt(masm_, "[ Declarations");
       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;
       DCHECK(jssp.Is(__ StackPointer()));
@@ skipping 498 matching lines @@
     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(x10, Heap::kTheHoleValueRootIndex);
         __ Str(x10, StackOperand(variable));
       }
       break;
 
-    case Variable::CONTEXT:
+    case VariableLocation::CONTEXT:
       if (hole_init) {
         Comment cmnt(masm_, "[ VariableDeclaration");
         EmitDebugCheckDeclarationContext(variable);
         __ LoadRoot(x10, Heap::kTheHoleValueRootIndex);
         __ Str(x10, ContextMemOperand(cp, variable->index()));
         // 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");
       __ Mov(x2, Operand(variable->name()));
       // Declaration nodes are always introduced in one of four modes.
       DCHECK(IsDeclaredVariableMode(mode));
       PropertyAttributes attr = IsImmutableVariableMode(mode) ? READ_ONLY
                                                               : NONE;
       __ Mov(x1, 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
@@ skipping 10 matching lines @@
     }
   }
 }
 
 
 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_, "[ Function Declaration");
       VisitForAccumulatorValue(declaration->fun());
       __ Str(result_register(), StackOperand(variable));
       break;
     }
 
-    case Variable::CONTEXT: {
+    case VariableLocation::CONTEXT: {
       Comment cmnt(masm_, "[ Function Declaration");
       EmitDebugCheckDeclarationContext(variable);
       VisitForAccumulatorValue(declaration->fun());
       __ Str(result_register(), ContextMemOperand(cp, variable->index()));
       int offset = Context::SlotOffset(variable->index());
       // We know that we have written a function, which is not a smi.
       __ RecordWriteContextSlot(cp,
                                 offset,
                                 result_register(),
                                 x2,
                                 kLRHasBeenSaved,
                                 kDontSaveFPRegs,
                                 EMIT_REMEMBERED_SET,
                                 OMIT_SMI_CHECK);
       PrepareForBailoutForId(proxy->id(), NO_REGISTERS);
       break;
     }
 
-    case Variable::LOOKUP: {
+    case VariableLocation::LOOKUP: {
       Comment cmnt(masm_, "[ Function Declaration");
       __ Mov(x2, Operand(variable->name()));
       __ Mov(x1, Smi::FromInt(NONE));
       __ Push(cp, x2, x1);
       // Push initial value for function declaration.
       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::GLOBAL:
+    case VariableLocation::UNALLOCATED:
       // 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 457 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");
       __ Ldr(LoadDescriptor::ReceiverRegister(), GlobalObjectMemOperand());
       __ Mov(LoadDescriptor::NameRegister(), Operand(var->name()));
       __ Mov(LoadDescriptor::SlotRegister(),
              SmiFromSlot(proxy->VariableFeedbackSlot()));
       CallGlobalLoadIC(var->name());
       context()->Plug(x0);
       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 variable"
                               : "Stack variable");
       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 49 matching lines @@
             __ Bind(&done);
           }
           context()->Plug(x0);
           break;
         }
       }
       context()->Plug(var);
       break;
     }
 
-    case Variable::LOOKUP: {
+    case VariableLocation::LOOKUP: {
       Label done, slow;
       // Generate code for loading from variables potentially shadowed by
       // eval-introduced variables.
       EmitDynamicLookupFastCase(proxy, NOT_INSIDE_TYPEOF, &slow, &done);
       __ Bind(&slow);
       Comment cmnt(masm_, "Lookup variable");
       __ Mov(x1, Operand(var->name()));
       __ Push(cp, x1);  // Context and name.
       __ CallRuntime(Runtime::kLoadLookupSlot, 2);
       __ Bind(&done);
@@ skipping 841 matching lines @@
     int offset = Context::SlotOffset(var->index());
     __ RecordWriteContextSlot(
         x1, offset, x10, x11, kLRHasBeenSaved, kDontSaveFPRegs);
   }
 }
 
 
 void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
                                                FeedbackVectorICSlot slot) {
   ASM_LOCATION("FullCodeGenerator::EmitVariableAssignment");
-  if (var->IsUnallocated()) {
+  if (var->IsUnallocatedOrGlobalSlot()) {
     // Global var, const, or let.
     __ Mov(StoreDescriptor::NameRegister(), Operand(var->name()));
     __ Ldr(StoreDescriptor::ReceiverRegister(), GlobalObjectMemOperand());
     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 2042 matching lines @@
         __ Mov(x10, Smi::FromInt(language_mode()));
         __ Push(x10);
         __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
         context()->Plug(x0);
       } 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()) {
           __ Ldr(x12, GlobalObjectMemOperand());
           __ Mov(x11, Operand(var->name()));
           __ Mov(x10, Smi::FromInt(SLOPPY));
           __ Push(x12, x11, x10);
           __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
           context()->Plug(x0);
         } else if (var->IsStackAllocated() || var->IsContextSlot()) {
           // Result of deleting non-global, non-dynamic variables is false.
           // The subexpression does not have side effects.
           context()->Plug(is_this);
@@ skipping 334 matching lines @@
       break;
     }
   }
 }
 
 
 void FullCodeGenerator::VisitForTypeofValue(Expression* expr) {
   DCHECK(!context()->IsEffect());
   DCHECK(!context()->IsTest());
   VariableProxy* proxy = expr->AsVariableProxy();
-  if (proxy != NULL && proxy->var()->IsUnallocated()) {
+  if (proxy != NULL && proxy->var()->IsUnallocatedOrGlobalSlot()) {
     Comment cmnt(masm_, "Global variable");
     __ Ldr(LoadDescriptor::ReceiverRegister(), GlobalObjectMemOperand());
     __ Mov(LoadDescriptor::NameRegister(), Operand(proxy->name()));
     __ Mov(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(x0);
@@ skipping 735 matching lines @@
   }
 
   return INTERRUPT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64