[builtins] support exception handling in TFJ builtins

src/compiler/code-assembler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-assembler.h"
 
 #include <ostream>
 
 #include "src/code-factory.h"
 #include "src/compiler/graph.h"
@@ skipping 294 matching lines @@
 
 void CodeAssembler::BranchIf(Node* condition, Label* if_true, Label* if_false) {
   Label if_condition_is_true(this), if_condition_is_false(this);
   Branch(condition, &if_condition_is_true, &if_condition_is_false);
   Bind(&if_condition_is_true);
   Goto(if_true);
   Bind(&if_condition_is_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();
   Node* return_value = raw_assembler_->CallN(descriptor, code_target, args);
   CallEpilogue();
   return return_value;
 }
 
 Node* CodeAssembler::TailCallN(CallDescriptor* descriptor, Node* code_target,
                                Node** args) {
@@ skipping 727 matching lines @@
       }
     }
   }
 
   bound_ = true;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8