X64: Port r6635 and r6659...

src/x64/macro-assembler-x64.cc

 // Copyright 2010 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 2513 matching lines @@
     // Move up the chain of contexts to the context containing the slot.
     movq(dst, Operand(rsi, Context::SlotOffset(Context::CLOSURE_INDEX)));
     // Load the function context (which is the incoming, outer context).
     movq(dst, FieldOperand(dst, JSFunction::kContextOffset));
     for (int i = 1; i < context_chain_length; i++) {
       movq(dst, Operand(dst, Context::SlotOffset(Context::CLOSURE_INDEX)));
       movq(dst, FieldOperand(dst, JSFunction::kContextOffset));
     }
     // The context may be an intermediate context, not a function context.
     movq(dst, Operand(dst, Context::SlotOffset(Context::FCONTEXT_INDEX)));
-  } else {  // context is the current function context.
-    // The context may be an intermediate context, not a function context.
-    movq(dst, Operand(rsi, Context::SlotOffset(Context::FCONTEXT_INDEX)));
+  } else {
+    // Slot is in the current function context.  Move it into the
+    // destination register in case we store into it (the write barrier
+    // cannot be allowed to destroy the context in esi).

[William Hesse, 2011/02/24 10:32:15]

rsi, not esi.

[Søren Thygesen Gjesse, 2011/02/24 11:33:18]

Done.

+    movq(dst, rsi);
+  }
+
+  // We should not have found a 'with' context by walking the context chain
+  // (i.e., the static scope chain and runtime context chain do not agree).
+  // A variable occurring in such a scope should have slot type LOOKUP and
+  // not CONTEXT.
+  if (FLAG_debug_code) {
+    cmpq(dst, Operand(dst, Context::SlotOffset(Context::FCONTEXT_INDEX)));
+    Check(equal, "Yo dawg, I heard you liked function contexts "
+                 "so I put function contexts in all your contexts");
   }
 }
 
 
 void MacroAssembler::LoadGlobalFunction(int index, Register function) {
   // Load the global or builtins object from the current context.
   movq(function, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
   // Load the global context from the global or builtins object.
   movq(function, FieldOperand(function, GlobalObject::kGlobalContextOffset));
   // Load the function from the global context.
@@ skipping 87 matching lines @@
   CPU::FlushICache(address_, size_);
 
   // Check that the code was patched as expected.
   ASSERT(masm_.pc_ == address_ + size_);
   ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64