Add support for global variable references in toplevel code. We use...

src/x64/fast-codegen-x64.cc

Index: src/x64/fast-codegen-x64.cc
===================================================================
--- src/x64/fast-codegen-x64.cc	(revision 3095)
+++ src/x64/fast-codegen-x64.cc	(working copy)
@@ -146,12 +146,31 @@
 void FastCodeGenerator::VisitVariableProxy(VariableProxy* expr) {
   Comment cmnt(masm_, "[ VariableProxy");
   Expression* rewrite = expr->var()->rewrite();
-  ASSERT(rewrite != NULL);
+  if (rewrite == NULL) {

[fschneider, 2009/10/20 14:16:17]

Insert a comment here:

Comment cmnt(masm_, "[Load from global property");

+    // Reference to a global variable, use inline caching. Variable
+    // name is passed in ecx and the global object on the stack.
+    __ push(CodeGenerator::GlobalObject());
+    __ Move(rcx, expr->name());
+    Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
+    __ Call(ic, RelocInfo::CODE_TARGET_CONTEXT);
 
-  Slot* slot = rewrite->AsSlot();
-  ASSERT(slot != NULL);
-  { Comment cmnt(masm_, "[ Slot");
+    // A test rax instruction following the call is used by the IC to
+    // indicate that the inobject property case was inlined.  Ensure there
+    // is no test rax instruction here.
     if (expr->location().is_temporary()) {
+      // Replace the global object with the result.
+      __ movq(Operand(rsp, 0), rax);
+    } else {
+      ASSERT(expr->location().is_nowhere());
+      __ pop(rax);
+    }
+
+  } else {
+    // Reference to a local or parameter slot.
+    Comment cmnt(masm_, "[ Slot");
+    Slot* slot = rewrite->AsSlot();
+    ASSERT(slot != NULL);
+    if (expr->location().is_temporary()) {
       __ push(Operand(rbp, SlotOffset(slot)));
     } else {
       ASSERT(expr->location().is_nowhere());