ARM: Port r6635 and r6659...

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
===================================================================
--- src/arm/macro-assembler-arm.cc	(revision 6881)
+++ src/arm/macro-assembler-arm.cc	(working copy)
@@ -2155,12 +2155,24 @@
       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");
+  }
+
 }