MIPS: Fix materialization of arguments objects with unknown values.

Port r13763 (6b32e7d6)

Original commit message:
This fixes the deoptimizer to materialize arguments objects of correct
length even in cases where the actual argument values are unknown and
were optimized away by Crankshaft. This can happen if only the length
property or the identity of an arguments object is used.

BUG=

Review URL: https://codereview.chromium.org/12383076

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13803 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/lithium-codegen-mips.cc

@@ -573,8 +573,8 @@ MemOperand LCodeGen::ToHighMemOperand(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.
@@ -586,13 +586,13 @@ 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
@@ -625,13 +625,20 @@ 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) {
@@ -646,8 +653,9 @@ 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) {
@@ -657,8 +665,9 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
             environment->spilled_double_registers()[value->index()],
             false,
             false,
-            *arguments_index,
-            *arguments_count);
+            arguments_known,
+            arguments_index,
+            arguments_count);
       }
     }
 
@@ -666,8 +675,9 @@ void LCodeGen::WriteTranslation(LEnvironment* environment,
                      value,
                      environment->HasTaggedValueAt(i),
                      environment->HasUint32ValueAt(i),
-                     *arguments_index,
-                     *arguments_count);
+                     arguments_known,
+                     arguments_index,
+                     arguments_count);
   }
 }
 
@@ -676,13 +686,15 @@ 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());

src/mips/lithium-codegen-mips.h

@@ -274,6 +274,7 @@ class LCodeGen BASE_EMBEDDED {
                         LOperand* op,
                         bool is_tagged,
                         bool is_uint32,
+                        bool arguments_known,
                         int arguments_index,
                         int arguments_count);
   void RegisterDependentCodeForEmbeddedMaps(Handle<Code> code);