Enable writes and reads of context slots in fast compiler.

src/ia32/fast-codegen-ia32.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 392 matching lines @@
   __ push(Immediate(boilerplate));
   __ CallRuntime(Runtime::kNewClosure, 2);
   Move(expr->context(), eax);
 }
 
 
 void FastCodeGenerator::VisitVariableProxy(VariableProxy* expr) {
   Comment cmnt(masm_, "[ VariableProxy");
   Expression* rewrite = expr->var()->rewrite();
   if (rewrite == NULL) {
+    ASSERT(expr->var()->is_global());
     Comment cmnt(masm_, "Global variable");
     // Use inline caching. Variable name is passed in ecx and the global
     // object on the stack.
     __ push(CodeGenerator::GlobalObject());
     __ mov(ecx, expr->name());
     Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET_CONTEXT);
     // By emitting a nop we make sure that we do not have a test eax
     // instruction after the call it is treated specially by the LoadIC code
     // Remember that the assembler may choose to do peephole optimization
     // (eg, push/pop elimination).
     __ nop();
 
     DropAndMove(expr->context(), eax);
   } else {
-    Comment cmnt(masm_, "Stack slot");
-    Move(expr->context(), rewrite->AsSlot());
+    Slot* slot = rewrite->AsSlot();
+    ASSERT_NE(NULL, slot);
+    switch (slot->type()) {
+      case Slot::LOCAL:
+      case Slot::PARAMETER: {
+        Comment cmnt(masm_, "Stack slot");
+        Move(expr->context(), slot);
+        break;
+      }
+
+      case Slot::CONTEXT: {
+        Comment cmnt(masm_, "Context slot");
+         int chain_length =
+            function_->scope()->ContextChainLength(slot->var()->scope());
+        if (chain_length > 0) {
+          // Move up the chain of contexts to the context containing the slot.
+          __ mov(eax,
+                 Operand(esi, Context::SlotOffset(Context::CLOSURE_INDEX)));
+          // Load the function context (which is the incoming, outer context).
+          __ mov(eax, FieldOperand(eax, JSFunction::kContextOffset));
+          for (int i = 1; i < chain_length; i++) {
+            __ mov(eax,
+                   Operand(eax, Context::SlotOffset(Context::CLOSURE_INDEX)));
+            __ mov(eax, FieldOperand(eax, JSFunction::kContextOffset));
+          }
+          // The context may be an intermediate context, not a function context.
+          __ mov(eax,
+                 Operand(eax, Context::SlotOffset(Context::FCONTEXT_INDEX)));
+        } else {  // Slot is in the current function context.
+          // The context may be an intermediate context, not a function context.
+          __ mov(eax,
+                 Operand(esi, Context::SlotOffset(Context::FCONTEXT_INDEX)));
+        }
+        __ mov(eax, Operand(eax, Context::SlotOffset(slot->index())));
+        Move(expr->context(), eax);
+        break;
+      }
+
+      case Slot::LOOKUP:
+        UNREACHABLE();
+        break;
+    }
   }
 }
 
 
 void FastCodeGenerator::VisitRegExpLiteral(RegExpLiteral* expr) {
   Comment cmnt(masm_, "[ RegExpLiteral");
   Label done;
   // Registers will be used as follows:
   // edi = JS function.
   // ebx = literals array.
@@ skipping 246 matching lines @@
     // ecx, and the global object on the stack.
     __ pop(eax);
     __ mov(ecx, var->name());
     __ push(CodeGenerator::GlobalObject());
     Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
     // Overwrite the receiver on the stack with the result if needed.
     DropAndMove(expr->context(), eax);
 
   } else {
-    switch (expr->context()) {
-      case Expression::kUninitialized:
-        UNREACHABLE();
-      case Expression::kEffect:
-        // Perform assignment and discard value.
-        __ pop(Operand(ebp, SlotOffset(var->slot())));
-        break;
-      case Expression::kValue:
-        // Perform assignment and preserve value.
-        __ mov(eax, Operand(esp, 0));
-        __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
-        break;
-      case Expression::kTest:
-        // Perform assignment and test (and discard) value.
-        __ pop(eax);
-        __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
-        TestAndBranch(eax, true_label_, false_label_);
-        break;
-      case Expression::kValueTest: {
-        Label discard;
-        __ mov(eax, Operand(esp, 0));
-        __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
-        TestAndBranch(eax, true_label_, &discard);
-        __ bind(&discard);
-        __ add(Operand(esp), Immediate(kPointerSize));
-        __ jmp(false_label_);
+    Slot* slot = var->slot();
+    ASSERT_NOT_NULL(slot);  // Variables rewritten as properties not handled.
+    switch (slot->type()) {
+      case Slot::LOCAL:
+      case Slot::PARAMETER: {
+        switch (expr->context()) {
+          case Expression::kUninitialized:
+            UNREACHABLE();
+          case Expression::kEffect:
+            // Perform assignment and discard value.
+            __ pop(Operand(ebp, SlotOffset(var->slot())));
+            break;
+          case Expression::kValue:
+            // Perform assignment and preserve value.
+            __ mov(eax, Operand(esp, 0));
+            __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
+            break;
+          case Expression::kTest:
+            // Perform assignment and test (and discard) value.
+            __ pop(eax);
+            __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
+            TestAndBranch(eax, true_label_, false_label_);
+            break;
+          case Expression::kValueTest: {
+            Label discard;
+            __ mov(eax, Operand(esp, 0));
+            __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
+            TestAndBranch(eax, true_label_, &discard);
+            __ bind(&discard);
+            __ add(Operand(esp), Immediate(kPointerSize));
+            __ jmp(false_label_);
+            break;
+          }
+          case Expression::kTestValue: {
+            Label discard;
+            __ mov(eax, Operand(esp, 0));
+            __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
+            TestAndBranch(eax, &discard, false_label_);
+            __ bind(&discard);
+            __ add(Operand(esp), Immediate(kPointerSize));
+            __ jmp(true_label_);
+            break;
+          }
+        }
         break;
       }
-      case Expression::kTestValue: {
-        Label discard;
-        __ mov(eax, Operand(esp, 0));
-        __ mov(Operand(ebp, SlotOffset(var->slot())), eax);
-        TestAndBranch(eax, &discard, false_label_);
-        __ bind(&discard);
-        __ add(Operand(esp), Immediate(kPointerSize));
-        __ jmp(true_label_);
+
+      case Slot::CONTEXT: {
+        int chain_length =
+            function_->scope()->ContextChainLength(slot->var()->scope());
+        if (chain_length > 0) {
+          // Move up the context chain to the context containing the slot.
+          __ mov(eax,
+                  Operand(esi, Context::SlotOffset(Context::CLOSURE_INDEX)));
+          // Load the function context (which is the incoming, outer context).
+          __ mov(eax, FieldOperand(eax, JSFunction::kContextOffset));
+          for (int i = 1; i < chain_length; i++) {
+            __ mov(eax,
+                    Operand(eax, Context::SlotOffset(Context::CLOSURE_INDEX)));
+            __ mov(eax, FieldOperand(eax, JSFunction::kContextOffset));
+          }
+        } else {  // Slot is in the current context.  Generate optimized code.
+          __ mov(eax, esi);  // RecordWrite destroys the object register.
+        }
+        if (FLAG_debug_code) {
+          __ cmp(eax,
+                  Operand(eax, Context::SlotOffset(Context::FCONTEXT_INDEX)));
+          __ Check(equal, "Context Slot chain length wrong.");
+        }
+        __ pop(ecx);
+        __ mov(Operand(eax, Context::SlotOffset(slot->index())), ecx);
+
+        // RecordWrite may destroy all its register arguments.
+        if (expr->context() == Expression::kValue) {
+          __ push(ecx);
+        } else if (expr->context() != Expression::kEffect) {
+          __ mov(edx, ecx);
+        }
+        int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
+        __ RecordWrite(eax, offset, ecx, ebx);
+        if (expr->context() != Expression::kEffect &&
+            expr->context() != Expression::kValue) {
+          Move(expr->context(), edx);
+        }
         break;
       }
+
+      case Slot::LOOKUP:
+        UNREACHABLE();
+        break;
     }
   }
 }
 
 
 void FastCodeGenerator::EmitNamedPropertyAssignment(Assignment* expr) {
   // Assignment to a property, using a named store IC.
   Property* prop = expr->target()->AsProperty();
   ASSERT(prop != NULL);
   ASSERT(prop->key()->AsLiteral() != NULL);
@@ skipping 665 matching lines @@
   true_label_ = saved_true;
   false_label_ = saved_false;
   // Convert current context to test context: End post-test code.
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal