Generator objects can suspend

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 19989b1c626dd3ea85f6cb9c3c44d7bfab8dffa9..bdff49852c2d900ff3100c6acf5d0e62d770389b 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -1883,6 +1883,46 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
 }
 
 
+void FullCodeGenerator::VisitYield(Yield* expr) {
+  Comment cmnt(masm_, "[ Yield");
+  // Evaluate yielded value first; the initial iterator definition depends on
+  // this.  It stays on the stack while we update the iterator.
+  VisitForStackValue(expr->expression());
+  VisitForStackValue(expr->generator_object());
+
+  if (expr->kind() == Yield::FINAL) {

[Michael Starzinger, 2013/04/17 13:43:48]

For the record: I think it will be best to just pass the yield kind as a second
parameter to the suspend runtime functions, because we will have different state
transitions depending on the kind. But let's not worry about that now for the
purpose of this CL.

+    // TODO(wingo): Mark the iterator as closed.
+  } else {
+    __ CallRuntime(Runtime::kSuspendJSGeneratorObject, 1);
+    __ mov(context_register(),
+           Operand(ebp, StandardFrameConstants::kContextOffset));
+  }
+
+  Label resume;
+  __ CompareRoot(result_register(), Heap::kTheHoleValueRootIndex);
+  __ j(not_equal, &resume);
+  switch (expr->kind()) {
+    case Yield::INITIAL:
+      __ pop(result_register());
+      break;
+    case Yield::SUSPEND:
+      // TODO(wingo): Box into { value: VALUE, done: false }.
+      __ pop(result_register());
+      break;
+    case Yield::FINAL:
+      // TODO(wingo): Box into { value: VALUE, done: true }.
+      __ pop(result_register());
+      break;
+    case Yield::DELEGATING:
+      UNIMPLEMENTED();
+  }
+  EmitReturnSequence();
+
+  __ bind(&resume);
+  context()->Plug(result_register());
+}
+
+
 void FullCodeGenerator::EmitNamedPropertyLoad(Property* prop) {
   SetSourcePosition(prop->position());
   Literal* key = prop->key()->AsLiteral();