[builtins] support exception handling in TFJ builtins

src/compiler/raw-machine-assembler.h

 // Copyright 2014 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.
 
 #ifndef V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 #define V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 
 #include "src/assembler.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
@@ skipping 730 matching lines @@
                          Node* arg3, Node* arg4, Node* arg5, Node* context);
 
   // ===========================================================================
   // The following utility methods deal with control flow, hence might switch
   // the current basic block or create new basic blocks for labels.
 
   // Control flow.
   void Goto(RawMachineLabel* label);
   void Branch(Node* condition, RawMachineLabel* true_val,
               RawMachineLabel* false_val);
+  void BranchIfException(Node* node, RawMachineLabel* if_exception);

[caitp, 2016/08/18 03:08:57]

I very much prefer a separate method vs adding optional if_exception Labels to
the millions of operations that the various Assemblers can perform.

   void Switch(Node* index, RawMachineLabel* default_label,
               const int32_t* case_values, RawMachineLabel** case_labels,
               size_t case_count);
   void Return(Node* value);
   void Return(Node* v1, Node* v2);
   void Return(Node* v1, Node* v2, Node* v3);
   void Bind(RawMachineLabel* label);
   void Deoptimize(Node* state);
   void DebugBreak();
   void Comment(const char* msg);
@@ skipping 65 matching lines @@
   bool deferred_;
   friend class RawMachineAssembler;
   DISALLOW_COPY_AND_ASSIGN(RawMachineLabel);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_