[builtins] support exception handling in TFJ builtins

src/compiler/code-assembler.cc

Index: src/compiler/code-assembler.cc
diff --git a/src/compiler/code-assembler.cc b/src/compiler/code-assembler.cc
index 6fd143b4dd9dd494e7e0485d9472896535c05e93..3dfdb1982f20eafb4e0c402799a891962b6f642b 100644
--- a/src/compiler/code-assembler.cc
+++ b/src/compiler/code-assembler.cc
@@ -312,6 +312,26 @@ void CodeAssembler::BranchIf(Node* condition, Label* if_true, Label* if_false) {
   Goto(if_false);
 }
 
+void CodeAssembler::GotoIfException(Node* node, Label* if_exception,
+                                    Variable* exception_var) {
+  Label success(this), exception(this, Label::kDeferred);
+  success.MergeVariables();
+  exception.MergeVariables();
+  DCHECK(!node->op()->HasProperty(Operator::kNoThrow));
+
+  raw_assembler_->Continuations(node, success.label_, exception.label_);
+
+  Bind(&exception);
+  const Operator* op = raw_assembler_->common()->IfException();
+  raw_assembler_->AddNode(op, node, node);
+  if (exception_var != nullptr) {
+    exception_var->Bind(node);

[Michael Starzinger, 2016/08/19 18:37:43]

nit: Technically the exception is the value output of the IfException node
instead of the call node. For a scheduled graph (as the RawMachineAssember is
building) where we are only dealing with calls that have at least one return
value, it shouldn't really matter all too much. But I would still go with using
the IfException node here (unless that causes unexpected troubles somewhere).

[caitp, 2016/08/19 20:37:11]

passes the tests, so if this is what's expected, seems okay

+  }
+  Goto(if_exception);
+
+  Bind(&success);
+}
+
 Node* CodeAssembler::CallN(CallDescriptor* descriptor, Node* code_target,
                            Node** args) {
   CallPrologue();