ARM: Port r6635 and r6659...

src/arm/macro-assembler-arm.cc

 // Copyright 2011 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 2137 matching lines @@
 void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
   if (context_chain_length > 0) {
     // Move up the chain of contexts to the context containing the slot.
     ldr(dst, MemOperand(cp, Context::SlotOffset(Context::CLOSURE_INDEX)));
     // Load the function context (which is the incoming, outer context).
     ldr(dst, FieldMemOperand(dst, JSFunction::kContextOffset));
     for (int i = 1; i < context_chain_length; i++) {
       ldr(dst, MemOperand(dst, Context::SlotOffset(Context::CLOSURE_INDEX)));
       ldr(dst, FieldMemOperand(dst, JSFunction::kContextOffset));
     }
-    // The context may be an intermediate context, not a function context.
-    ldr(dst, MemOperand(dst, Context::SlotOffset(Context::FCONTEXT_INDEX)));
-  } else {  // Slot is in the current function context.
-    // The context may be an intermediate context, not a function context.
-    ldr(dst, MemOperand(cp, 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).
+    mov(dst, cp);
   }
+
+  // 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) {
+    ldr(ip, MemOperand(dst, Context::SlotOffset(Context::FCONTEXT_INDEX)));
+    cmp(dst, ip);
+    Check(eq, "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.
   ldr(function, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
   // Load the global context from the global or builtins object.
   ldr(function, FieldMemOperand(function,
                                 GlobalObject::kGlobalContextOffset));
   // Load the function from the global context.
@@ skipping 376 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM