[WASM] Implements catch for the wasm low level exception mechanism.

src/frames.cc

 // Copyright 2012 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/frames.h"
 
 #include <memory>
 #include <sstream>
 
 #include "src/base/bits.h"
@@ skipping 1459 matching lines @@
   DCHECK(deopt_data->length() == 2);
   return Smi::cast(deopt_data->get(1))->value();
 }
 
 Script* WasmFrame::script() const {
   Handle<JSObject> wasm(JSObject::cast(wasm_obj()), isolate());
   Handle<wasm::WasmDebugInfo> debug_info = wasm::GetDebugInfo(wasm);
   return wasm::WasmDebugInfo::GetFunctionScript(debug_info, function_index());
 }
 
+int WasmFrame::LookupExceptionHandlerInTable(int* stack_slots) {
+  DCHECK_NOT_NULL(stack_slots);
+  Code* code = LookupCode();
+  HandlerTable* table = HandlerTable::cast(code->handler_table());
+  int pc_offset = static_cast<int>(pc() - code->entry());
+  *stack_slots = code->stack_slots();
+  return table->LookupReturn(pc_offset);
+}
+
 namespace {
 
 
 void PrintFunctionSource(StringStream* accumulator, SharedFunctionInfo* shared,
                          Code* code) {
   if (FLAG_max_stack_trace_source_length != 0 && code != NULL) {
     std::ostringstream os;
     os << "--------- s o u r c e   c o d e ---------\n"
        << SourceCodeOf(shared, FLAG_max_stack_trace_source_length)
        << "\n-----------------------------------------\n";
@@ skipping 418 matching lines @@
   for (StackFrameIterator it(isolate); !it.done(); it.Advance()) {
     StackFrame* frame = AllocateFrameCopy(it.frame(), zone);
     list.Add(frame, zone);
   }
   return list.ToVector();
 }
 
 
 }  // namespace internal
 }  // namespace v8