Make Scanner::kNoSourcePos be a true sentinel value

runtime/vm/flow_graph_builder.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/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/compiler.h"
@@ skipping 2266 matching lines @@
 
 LocalVariable* EffectGraphVisitor::EnterTempLocalScope(Value* value) {
   Do(new(Z) PushTempInstr(value));
   owner()->AllocateTemp();
 
   ASSERT(value->definition()->temp_index() == (owner()->temp_count() - 1));
   intptr_t index = GetCurrentTempLocalIndex();
   char name[64];
   OS::SNPrint(name, 64, ":tmp_local%" Pd, index);
   LocalVariable*  var =
-      new(Z) LocalVariable(0,
+      new(Z) LocalVariable(Scanner::kNoSourcePos,
                            String::ZoneHandle(Z, Symbols::New(name)),
                            *value->Type()->ToAbstractType());
   var->set_index(index);
   return var;
 }
 
 
 Definition* EffectGraphVisitor::ExitTempLocalScope(LocalVariable* var) {
   Value* tmp = Bind(new(Z) LoadLocalInstr(*var));
   owner()->DeallocateTemps(1);
@@ skipping 1697 matching lines @@
       const int num_params = function.NumParameters();
       int param_frame_index = (num_params == function.num_fixed_parameters()) ?
           (kParamEndSlotFromFp + num_params) : kFirstLocalSlotFromFp;
       for (int pos = 0; pos < num_params; param_frame_index--, pos++) {
         const LocalVariable& parameter = *scope->VariableAt(pos);
         ASSERT(parameter.owner() == scope);
         if (parameter.is_captured()) {
           // Create a temporary local describing the original position.
           const String& temp_name = Symbols::TempParam();
           LocalVariable* temp_local = new(Z) LocalVariable(
-              0,  // Token index.
+              Scanner::kNoSourcePos,  // Token index.
               temp_name,
               Object::dynamic_type());  // Type.
           temp_local->set_index(param_frame_index);
 
           // Mark this local as captured parameter so that the optimizer
           // correctly handles these when compiling try-catch: Captured
           // parameters are not in the stack environment, therefore they
           // must be skipped when emitting sync-code in try-blocks.
           temp_local->set_is_captured_parameter(true);
 
@@ skipping 20 matching lines @@
     // are in scope in the debugger at method entry.
     const int num_params = function.NumParameters();
     intptr_t check_pos = Scanner::kNoSourcePos;
     if (num_params > 0) {
       const LocalVariable& parameter = *scope->VariableAt(num_params - 1);
       check_pos = parameter.token_pos();
     }
     if (check_pos == Scanner::kNoSourcePos) {
       // No parameters or synthetic parameters.
       check_pos = node->token_pos();
+      ASSERT(check_pos != Scanner::kNoSourcePos);
     }
     AddInstruction(new(Z) DebugStepCheckInstr(check_pos,
                                               RawPcDescriptors::kRuntimeCall));
   }
 
   // This check may be deleted if the generated code is leaf.
   // Native functions don't need a stack check at entry.
   if (is_top_level_sequence && !function.is_native()) {
     // Always allocate CheckOverflowInstr so that deopt-ids match regardless
     // if we inline or not.
@@ skipping 524 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart