Implement argument definition test in the vm.

runtime/vm/scopes.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/scopes.h"
 
 #include "vm/ast.h"
 #include "vm/bit_vector.h"
 #include "vm/object.h"
 #include "vm/parser.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
-const char* SourceLabel::kDefaultLabelName = ":L";
-
-const char* LocalVariable::kSavedContextVarName = ":saved_entry_context_var";
-
-
 int SourceLabel::FunctionLevel() const {
   ASSERT(owner() != NULL);
   return owner()->function_level();
 }
 
 
 LocalScope::LocalScope(LocalScope* parent, int function_level, int loop_level)
     : parent_(parent),
       child_(NULL),
       sibling_(NULL),
@@ skipping 196 matching lines @@
 // Add variables that are declared in this scope to vars, then collect
 // variables of children, followed by siblings.
 void LocalScope::CollectLocalVariables(GrowableArray<VarDesc>* vars,
                                        int16_t* scope_id) {
   (*scope_id)++;
   if (HasContextLevel() &&
       ((parent() == NULL) ||
       (!parent()->HasContextLevel()) ||
       (parent()->context_level() != context_level()))) {
     // This is the outermost scope with a context level or this scope's
-    // context level differes from its parent's level.
+    // context level differs from its parent's level.
     VarDesc desc;
     desc.name = &String::Handle();  // No name.
     desc.info.kind =  RawLocalVarDescriptors::kContextLevel;
     desc.info.scope_id = *scope_id;
     desc.info.begin_pos = begin_token_pos();
     desc.info.end_pos = end_token_pos();
     desc.info.index = context_level();
     vars->Add(desc);
   }
   for (int i = 0; i < this->variables_.length(); i++) {
     LocalVariable* var = variables_[i];
     if (var->owner() == this) {
       if (!IsInternalIdentifier(var->name())) {
         // This is a regular Dart variable, either stack-based or captured.
         VarDesc desc;
         desc.name = &var->name();
         if (var->is_captured()) {
           desc.info.kind = RawLocalVarDescriptors::kContextVar;
           ASSERT(var->owner() != NULL);
           ASSERT(var->owner()->context_level() >= 0);
           desc.info.scope_id = var->owner()->context_level();
         } else {
           desc.info.kind = RawLocalVarDescriptors::kStackVar;
           desc.info.scope_id = *scope_id;
         }
         desc.info.begin_pos = var->token_pos();
         desc.info.end_pos = var->owner()->end_token_pos();
         desc.info.index = var->index();
         vars->Add(desc);
-      } else if (var->name().Equals(LocalVariable::kSavedContextVarName)) {
+      } else if (var->name().Equals(
+            Symbols::Name(Symbols::kSavedEntryContextVar))) {

[hausner, 2012/08/31 00:34:55]

Isn't it enough to just allocate a string handle for the symbol, which gets
allocated as a RawString.

...Equals(String::Handle(Symbols::SavedEntryContextVar()))

[regis, 2012/08/31 01:36:18]

Yes, but it seems like a waste to allocate all these handles in this recursive
function just to access a compile time char*. This is probably why you had the
static char* in the first place. I need also need a char* elsewhere for the
arg_desc variable name and I thought that making all these predefined symbols as
char* was convenient. But if it causes any issue, let's revisit.   

[hausner, 2012/08/31 05:56:26]

Ok, that's a valid reason that I buy. I hope Equals does not allocate a handle
(I don't have the source code handy).

On 2012/08/31 01:36:18, regis wrote:

         // This is the local variable in which the function saves the
         // caller's chain of closure contexts (caller's CTX register).
         VarDesc desc;
         desc.name = &var->name();
         desc.info.kind = RawLocalVarDescriptors::kContextChain;
         desc.info.scope_id = 0;
         desc.info.begin_pos = 0;
         desc.info.end_pos = 0;
         desc.info.index = var->index();
         vars->Add(desc);
       }
+      // The saved arguments descriptor variable is not currently collected.
     }
   }
   LocalScope* child = this->child();
   while (child != NULL) {
     child->CollectLocalVariables(vars, scope_id);
     child = child->sibling();
   }
 }
 
 
@@ skipping 264 matching lines @@
   } else {
     // Shift negative indexes so that the lowest one is 0 (they are still
     // non-positive).
     return fixed_parameter_count -
         (index() - ParsedFunction::kFirstLocalSlotIndex);
   }
 }
 
 
 }  // namespace dart