Revert "Fix stepping in for-loops."

src/mips64/full-codegen-mips64.cc

Index: src/mips64/full-codegen-mips64.cc
diff --git a/src/mips64/full-codegen-mips64.cc b/src/mips64/full-codegen-mips64.cc
index 72801d5715e263dd13aee3a4bf25942375e373a9..06c3bb45b5c400d7a72a118a69632833e8e21e31 100644
--- a/src/mips64/full-codegen-mips64.cc
+++ b/src/mips64/full-codegen-mips64.cc
@@ -1097,7 +1097,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Get the object to enumerate over. If the object is null or undefined, skip
   // over the loop.  See ECMA-262 version 5, section 12.6.4.
-  SetExpressionPosition(stmt->enumerable());
   VisitForAccumulatorValue(stmt->enumerable());
   __ mov(a0, result_register());  // Result as param to InvokeBuiltin below.
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
@@ -1239,7 +1238,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ mov(result_register(), a3);
   // Perform the assignment as if via '='.
   { EffectContext context(this);
-    SetExpressionPosition(stmt->each());
     EmitAssignment(stmt->each());
   }
 
@@ -1267,6 +1265,48 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 }
 
 
+void FullCodeGenerator::VisitForOfStatement(ForOfStatement* stmt) {
+  Comment cmnt(masm_, "[ ForOfStatement");
+  SetStatementPosition(stmt);
+
+  Iteration loop_statement(this, stmt);
+  increment_loop_depth();
+
+  // var iterator = iterable[Symbol.iterator]();
+  VisitForEffect(stmt->assign_iterator());
+
+  // Loop entry.
+  __ bind(loop_statement.continue_label());
+
+  // result = iterator.next()
+  VisitForEffect(stmt->next_result());
+
+  // if (result.done) break;
+  Label result_not_done;
+  VisitForControl(stmt->result_done(),
+                  loop_statement.break_label(),
+                  &result_not_done,
+                  &result_not_done);
+  __ bind(&result_not_done);
+
+  // each = result.value
+  VisitForEffect(stmt->assign_each());
+
+  // Generate code for the body of the loop.
+  Visit(stmt->body());
+
+  // Check stack before looping.
+  PrepareForBailoutForId(stmt->BackEdgeId(), NO_REGISTERS);
+  EmitBackEdgeBookkeeping(stmt, loop_statement.continue_label());
+  __ jmp(loop_statement.continue_label());
+
+  // Exit and decrement the loop depth.
+  PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
+  __ bind(loop_statement.break_label());
+  decrement_loop_depth();
+}
+
+
 void FullCodeGenerator::EmitNewClosure(Handle<SharedFunctionInfo> info,
                                        bool pretenure) {
   // Use the fast case closure allocation code that allocates in new