Fix materialization of arguments objects with unknown values.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 99d79fbb30a65b5b9312a774a0881fb33ef0b6ea..3f371bd69def9de1e8653fb95e71e11c8cc4ea7b 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -477,8 +477,8 @@ Operand LCodeGen::ToOperand(LOperand* op) const {
 
 void LCodeGen::WriteTranslation(LEnvironment* environment,
                                 Translation* translation,
-                                int* arguments_index,
-                                int* arguments_count) {
+                                int* pushed_arguments_index,
+                                int* pushed_arguments_count) {
   if (environment == NULL) return;
 
   // The translation includes one command per value in the environment.
@@ -490,13 +490,13 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
   // arguments index points to the first element of a sequence of tagged
   // values on the stack that represent the arguments. This needs to be
   // kept in sync with the LArgumentsElements implementation.
-  *arguments_index = -environment->parameter_count();
-  *arguments_count = environment->parameter_count();
+  *pushed_arguments_index = -environment->parameter_count();
+  *pushed_arguments_count = environment->parameter_count();
 
   WriteTranslation(environment->outer(),
                    translation,
-                   arguments_index,
-                   arguments_count);
+                   pushed_arguments_index,
+                   pushed_arguments_count);
   bool has_closure_id = !info()->closure().is_null() &&
       *info()->closure() != *environment->closure();
   int closure_id = has_closure_id
@@ -529,13 +529,20 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
   }
 
   // Inlined frames which push their arguments cause the index to be
-  // bumped and a new stack area to be used for materialization.
-  if (environment->entry() != NULL &&
-      environment->entry()->arguments_pushed()) {
-    *arguments_index = *arguments_index < 0
-        ? GetStackSlotCount()
-        : *arguments_index + *arguments_count;
-    *arguments_count = environment->entry()->arguments_count() + 1;
+  // bumped and another stack area to be used for materialization,
+  // otherwise actual argument values are unknown for inlined frames.
+  bool arguments_known = true;
+  int arguments_index = *pushed_arguments_index;
+  int arguments_count = *pushed_arguments_count;
+  if (environment->entry() != NULL) {
+    arguments_known = environment->entry()->arguments_pushed();
+    arguments_index = arguments_index < 0
+        ? GetStackSlotCount() : arguments_index + arguments_count;
+    arguments_count = environment->entry()->arguments_count() + 1;
+    if (environment->entry()->arguments_pushed()) {
+      *pushed_arguments_index = arguments_index;
+      *pushed_arguments_count = arguments_count;
+    }
   }
 
   for (int i = 0; i < translation_size; ++i) {
@@ -550,8 +557,9 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
                          environment->spilled_registers()[value->index()],
                          environment->HasTaggedValueAt(i),
                          environment->HasUint32ValueAt(i),
-                         *arguments_index,
-                         *arguments_count);
+                         arguments_known,
+                         arguments_index,
+                         arguments_count);
       } else if (
           value->IsDoubleRegister() &&
           environment->spilled_double_registers()[value->index()] != NULL) {
@@ -561,8 +569,9 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
             environment->spilled_double_registers()[value->index()],
             false,
             false,
-            *arguments_index,
-            *arguments_count);
+            arguments_known,
+            arguments_index,
+            arguments_count);
       }
     }
 
@@ -570,8 +579,9 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
                      value,
                      environment->HasTaggedValueAt(i),
                      environment->HasUint32ValueAt(i),
-                     *arguments_index,
-                     *arguments_count);
+                     arguments_known,
+                     arguments_index,
+                     arguments_count);
   }
 }
 
@@ -580,13 +590,15 @@ void LCodeGen::AddToTranslation(Translation* translation,
                                 LOperand* op,
                                 bool is_tagged,
                                 bool is_uint32,
+                                bool arguments_known,
                                 int arguments_index,
                                 int arguments_count) {
   if (op == NULL) {
     // TODO(twuerthinger): Introduce marker operands to indicate that this value
     // is not present and must be reconstructed from the deoptimizer. Currently
     // this is only used for the arguments object.
-    translation->StoreArgumentsObject(arguments_index, arguments_count);
+    translation->StoreArgumentsObject(
+        arguments_known, arguments_index, arguments_count);
   } else if (op->IsStackSlot()) {
     if (is_tagged) {
       translation->StoreStackSlot(op->index());