Simplify exception handler table

runtime/vm/debugger.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/debugger.h"
 
 #include "include/dart_api.h"
 
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 360 matching lines @@
     var_descriptors_.GetInfo(i, &var_info);
     if (var_info.kind == RawLocalVarDescriptors::kContextChain) {
       return reinterpret_cast<RawContext*>(GetLocalVarValue(var_info.index));
     }
   }
   // Caller uses same context chain.
   return ctx_.raw();
 }
 
 
-// TODO(hausner): Eliminate this helper function by sorting the
-// ExceptionHandlers entries by try_index and eliminating
-// the try_index field altogether.
-static intptr_t FindTryIndex(const ExceptionHandlers& handlers,
-                             intptr_t try_index) {
-  intptr_t len = handlers.Length();
-  for (int i = 0; i < len; i++) {
-    if (handlers.TryIndex(i) == try_index) return i;
-  }
-  UNREACHABLE();
-  return -1;
-}
-
-
 ActivationFrame* DebuggerStackTrace::GetHandlerFrame(
     const Instance& exc_obj) const {
   ExceptionHandlers& handlers = ExceptionHandlers::Handle();
   Array& handled_types = Array::Handle();
   AbstractType& type = Type::Handle();
   const TypeArguments& no_instantiator = TypeArguments::Handle();
   for (int frame_index = 0; frame_index < Length(); frame_index++) {
     ActivationFrame* frame = trace_[frame_index];
     intptr_t try_index = frame->TryIndex();
     if (try_index < 0) continue;
     const Code& code = frame->DartCode();
     handlers = code.exception_handlers();
     ASSERT(!handlers.IsNull());
     intptr_t num_handlers_checked = 0;
     while (try_index >= 0) {
-      intptr_t i = FindTryIndex(handlers, try_index);
       // Detect circles in the exception handler data.
       num_handlers_checked++;
       ASSERT(num_handlers_checked <= handlers.Length());
-      handled_types = handlers.GetHandledTypes(i);
+      handled_types = handlers.GetHandledTypes(try_index);
       const intptr_t num_types = handled_types.Length();
       for (int k = 0; k < num_types; k++) {
         type ^= handled_types.At(k);
         ASSERT(!type.IsNull());
         // Uninstantiated types are not added to ExceptionHandlers data.
         ASSERT(type.IsInstantiated());
         if (type.IsDynamicType()) return frame;
         if (type.IsMalformed()) continue;
         if (exc_obj.IsInstanceOf(type, no_instantiator, NULL)) {
           return frame;
         }
       }
-      try_index = handlers.OuterTryIndex(i);
+      try_index = handlers.OuterTryIndex(try_index);
     }
   }
   return NULL;
 }
 
 
 void ActivationFrame::GetDescIndices() {
   if (vars_initialized_) {
     return;
   }
@@ skipping 1299 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart