MIPS: Baseline for-of implementation.

Port r15002 (d2f0fac)

Original commit message:
Add full-codegen support for the ES6 for-of iteration statement.

TEST=mjsunit/harmony/iteration-semantics
BUG=v8:2214
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/15995040

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15015 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index fa85da6..10afeb1 100644 (file)
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -1084,9 +1084,8 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   ForIn loop_statement(this, stmt);
   increment_loop_depth();
 
-  // Get the object to enumerate over. Both SpiderMonkey and JSC
-  // ignore null and undefined in contrast to the specification; see
-  // ECMA-262 section 12.6.4.
+  // 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.
   VisitForAccumulatorValue(stmt->enumerable());
   __ mov(a0, result_register());  // Result as param to InvokeBuiltin below.
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
@@ -1260,6 +1259,67 @@ 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[@@iterator]()
+  VisitForAccumulatorValue(stmt->assign_iterator());
+  __ mov(a0, v0);
+
+  // As with for-in, skip the loop if the iterator is null or undefined.
+  __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
+  __ Branch(loop_statement.break_label(), eq, a0, Operand(at));
+  __ LoadRoot(at, Heap::kNullValueRootIndex);
+  __ Branch(loop_statement.break_label(), eq, a0, Operand(at));
+
+  // Convert the iterator to a JS object.
+  Label convert, done_convert;
+  __ JumpIfSmi(a0, &convert);
+  __ GetObjectType(a0, a1, a1);
+  __ Branch(&done_convert, ge, a1, Operand(FIRST_SPEC_OBJECT_TYPE));
+  __ bind(&convert);
+  __ push(a0);
+  __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
+  __ mov(a0, v0);
+  __ bind(&done_convert);
+  __ push(a0);
+
+  // 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