2008-06-20 Marek Safar <marek.safar@gmail.com>

[mono.git] / mcs / mcs / TODO

diff --git a/mcs/mcs/TODO b/mcs/mcs/TODO
index b484df0f32718bb8e36a7f9ba18b615835cbbcd7..741e63d2ab8cd6201491913c3bda9e15d599fee2 100644 (file)
--- a/mcs/mcs/TODO
+++ b/mcs/mcs/TODO
@@ -1,91 +1,140 @@
-Dead Code Elimination bugs:
----------------------------
+Iterators
+=========

 
 

-       I should also resolve all the children expressions in Switch, Fixed, Using.

 
 

-Major tasks:
-------------
+       Ok, solved part of the problem, but not the second.

 
 

-       Pinned and volatile require type modifiers that can not be encoded
-       with Reflection.Emit.
+       Apparently there are 2 scopes in test-iter-05.cs that
+       are referenced, but when we call "ComputeMethodHost" in
+       iterators.cs:854 this information is not yet available.

 
 

-       Properties and 17.6.3: Finish it.
+===========================================

 
 

-       Implement base indexer access.
+* Value Parameter

 
 

-readonly variables and ref/out
+       I believe that `Value Parameter' might have been introduced
+       after C# 1.0, also notice than in the treatment of Value Parameter
+       the parameters are defined in four categories:
+
+       Section 9.3 in the latest spec.
+
+
+Large project:
+--------------
+
+New
+---

 
 

-Important:
+       It would be nice to optimize the case of:
+
+               Method (new ValueType ())
+
+       So that no temporary is created, and we only use a newobj call
+       that remains on the stack, as opposed to ldloca, initobj, ldloc
+       call.
+
+NEW NOTES:

 ----------
 
 ----------
 

-       During enumeration definition, a set of extra operators are 
-       allowed.
-       
-BUGS
-----
+       ImplicitStandardConversionExists and ImplicitStandardConversion
+       should always be the same, but there are a few diverging lines that
+       must be studied:

 
 

-* Check for Final when overriding, if the parent is Final, then we cant
-  allow an override.
+                       if (expr_type == target_type && !(expr is NullLiteral))
+                               return expr;

 
 

-* Currently the code path for 108/109 reporting is not being ran for methods
-  as we need to compare method signatures.  But since we retrieve the expensive
-  method arguments in the method, we probably should do 108/109 processing there.
+       vs:

 
 

-* Emit warning on hiding members without NEW not only in members.
+                       if (expr_type == target_type)
+                               return true;

 
 

-* Implement visibility.
+****************************************************************************************
+* 
+*   The information on the rest of this file is mostly outdated, and its kept here for
+*   historical reasons
+*
+****************************************************************************************
+ 
+Error Reporting:
+----------------

 
 

-* Adding variables.
+       * Make yyerror show a nice syntax error, instead of the current mess.

 
 

-       We do add variables in a number of places, and this is erroneous:
+Iterators
+---------
+       * Reset should throw not implemented now.

 
 

-       void a (int b)
-       {
-               int b;
-       }
+Optimization ideas
+------------------

 
 

-       Also:
+       Currently when we build a type cache, it contains private members,
+       internal members, and internal protected members;   We should trim
+       these out, as it shows up on the profile.

 
 

-       void a (int b)
-       {
-               foreach (int b ...)
-                       ;
-       }
+       We create too many Arraylists;  When we know the size, we should create
+       an array;
+
+       During parsing we use arraylists to accumulate data, like this:

 
 

-* Visibility
+               thing:
+               
+               thing_list
+                       : thing { $$ =new ArrayList (); $$.Add ($1); }
+                       | thing_list thing { ArrayList a = $1; a.Add ($2); $$ = a; }
+
+       We probably could start using "Pairs" there:
+
+               thing_list
+                       : thing { $$ = new Pair ($1, null); }
+                       | thing_list thing { Pair p = $1; $$ = new Pair ($2, $1); }

 
 

-       I am not reporting errors on visibility yet.

 
 

-* Interface indexers
+EmitContext.ResolveTypeTree
+---------------------------
+
+       We should investigate its usage.  The problem is that by default
+       this will be set when calling FindType, that triggers a more expensive
+       lookup.

 
 

-       I have not figured out why the Microsoft version puts an
-       `instance' attribute, and I am not generating this `instance' attribute.
+       I believe we should pass the current EmitContext (which has this turned off
+       by default) to ResolveType/REsolveTypeExpr and then have the routines that
+       need ResolveType to pass null as the emit context.

 
 

-       Explanation: The reason for the `instance' attribute on
-       indexers is that indexers only apply to instances
+DeclareLocal audit
+------------------

 
 

-* Arrays
+       DeclareLocal is used in various statements.  The audit should be done
+       in two steps:

 
 

-       We need to make sure at *compile time* that the arguments in
-       the expression list of an array creation are always positive.
+               * Identify all the declare locals.

 
 

-* Implement dead code elimination in statement.cs
+               * Identify its uses.

 
 

-       It is pretty simple to implement dead code elimination in 
-       if/do/while
+               * Find if we can make wrapper functions for all of them.

 
 

-* Indexer bugs:
+       Then we can move DeclareLocal into a helper class.

 
 

-       the following wont work:
+       This is required to fix foreach in iterators.

 
 

-       x [0] = x [1] = N
+Ideas:
+------

 
 

-       if x has indexers, the value of x [N] set is set to void.  This needs to be
-       fixed.
+       Instead of the hack that *knows* about System.Object not having any children classes,
+       we should just make it simple for a probe to know that there is no need for it.

 
 

-* Array declarations
+Dead Code Elimination bugs:
+---------------------------
+
+       I should also resolve all the children expressions in Switch, Fixed, Using.
+
+Major tasks:
+------------
+       Properties and 17.6.3: Finish it.

 
 

-       Multi-dim arrays are declared as [,] instead of [0..,0..]
+readonly variables and ref/out
+       
+BUGS
+----

 
 * Break/Continue statements
 
 
 * Break/Continue statements
 


@@ -104,14 +153,6 @@ BUGS
        Method registration should only be used to register methodbuilders,
        we need an alternate method of checking for duplicates.
 
        Method registration should only be used to register methodbuilders,
        we need an alternate method of checking for duplicates.
 

-* We need to catch:
-
-       extern string Property {
-               get { } 
-       }
-
-       The get there should only have a semicolon
-       

 *
 > // CSC sets beforefieldinit
 > class X {
 *
 > // CSC sets beforefieldinit
 > class X {


@@ -126,16 +167,6 @@ PENDING TASKS
 
 * Merge test 89 and test-34
 
 
 * Merge test 89 and test-34
 

-* Revisit
-
-       Primary-expression, as it has now been split into 
-       non-array-creation-expression and array-creation-expression.
-               
-* Static flow analysis
-
-       Required to warn about reachability of code and definite
-       assignemt as well as missing returns on functions.
-

 * Code cleanup
 
        The information when registering a method in InternalParameters
 * Code cleanup
 
        The information when registering a method in InternalParameters


@@ -145,29 +176,13 @@ PENDING TASKS
 
        Handle modreq from public apis.
 
 
        Handle modreq from public apis.
 

-* Emit `pinned' for pinned local variables.
-
-       Both `modreq' and pinned will require special hacks in the compiler.
-
-* Make sure that we are pinning the right variable
-
-* Maybe track event usage?  Currently I am not tracking these, although they
-  are fields.
-

 * Merge tree.cs, rootcontext.cs
 
 OPTIMIZATIONS
 -------------
 
 * Merge tree.cs, rootcontext.cs
 
 OPTIMIZATIONS
 -------------
 

-* Implement loop inversion for `For' as well.
-
-* There is too much unshared code between MemberAccess.Resolve and SimpleName
-  resolve.  
- 

 * User Defined Conversions is doing way too many calls to do union sets that are not needed
 
 * User Defined Conversions is doing way too many calls to do union sets that are not needed
 

-* Implement loop inversion for our loops
-

 * Add test case for destructors
 
 * Places that use `Ldelema' are basically places where I will be
 * Add test case for destructors
 
 * Places that use `Ldelema' are basically places where I will be


@@ -184,47 +199,11 @@ OPTIMIZATIONS
        The only pending problem is that the code that implements Aliases
        is on TypeContainer, and probably should go in DeclSpace.
 
        The only pending problem is that the code that implements Aliases
        is on TypeContainer, and probably should go in DeclSpace.
 

-* Casts need to trigger a name resolution against types only.
-
-       currently we use a secret hand shake, probably we should use
-       a differen path, and only expressions (memberaccess, simplename)
-       would participate in this protocol.
-
-* Use of local temporary in UnaryMutator
-
-       We should get rid of the Localtemporary there for some cases
-
-* Emitcontext
-
-       Do we really need to instanciate this variable all the time?
-
-       It could be static for all we care, and just use it for making
-       sure that there are no recursive invocations on it.
-
-* Use of EmitBranchable
-
-       Currently I use brfalse/brtrue in the code for statements, instead of
-       using the EmitBranchable function that lives in Binary
-
-* ConvertImplicit
-
-       Currently ConvertImplicit will not catch things like:
-
-       - IntLiteral in a float context to generate a -FloatLiteral.
-       Instead it will perform an integer load followed by a conversion.
-

 * Tests
 
        Write tests for the various reference conversions.  We have
        test for all the numeric conversions.
 
 * Tests
 
        Write tests for the various reference conversions.  We have
        test for all the numeric conversions.
 

-* Optimizations
-
-       In Indexers and Properties, probably support an EmitWithDup
-       That emits the code to call Get and then leaves a this pointer
-       in the stack, so that later a Store can be emitted using that
-       this pointer (consider Property++ or Indexer++)
-

 * Optimizations: variable allocation.
 
        When local variables of a type are required, we should request
 * Optimizations: variable allocation.
 
        When local variables of a type are required, we should request


@@ -233,19 +212,11 @@ OPTIMIZATIONS
 
 * Add a cache for the various GetArrayMethod operations.
 
 
 * Add a cache for the various GetArrayMethod operations.
 

-* TypeManager.FindMembers:
-
-       Instead of having hundreds of builder_to_blah hash table, have
-       a single one that maps a TypeBuilder `t' to a set of classes
-       that implement an interface that supports FindMembers.
-

 * MakeUnionSet Callers
 
        If the types are the same, there is no need to compute the unionset,
        we can just use the list from one of the types.
 
 * MakeUnionSet Callers
 
        If the types are the same, there is no need to compute the unionset,
        we can just use the list from one of the types.
 

-* Factor all the FindMembers in all the FindMembers providers.
-

 * Factor the lookup code for class declarations an interfaces
   (interface.cs:GetInterfaceByName)
 
 * Factor the lookup code for class declarations an interfaces
   (interface.cs:GetInterfaceByName)
 


@@ -271,57 +242,14 @@ RECOMMENDATIONS
        Notice how numbering of the arguments changes as the
        { oob_stack.Push (lexer.Location) } takes a "slot"  in the productions.
 
        Notice how numbering of the arguments changes as the
        { oob_stack.Push (lexer.Location) } takes a "slot"  in the productions.
 

-* local_variable_declaration
-
-       Not sure that this grammar is correct, we might have to
-       resolve this during semantic analysis.
-
-* Optimizations
-
-       Only create one `This' instance per class, and reuse it.
-
-       Maybe keep a pool of constants/literals (zero, 1)?
-
-* Idea
-
-       MethodGroupExpr
-
-       These guys should only appear as part of an Invocation, so we
-       probably can afford to have a special callback:
-
-               Expression.ResolveAllowMemberGroups
-
-       This is only called by Invocation (or anyone that consumes 
-       MethodGroupExprs)
-
-       And the regular DoResolve and DoResolveLValue do emit the error
-       654 `Method referenced without argument list'.  
-
-       Otherwise, a resolution will return a MethodGroupExpr which is
-       not guaranteed to have set its `Expression.Type' to a non-null
-       value.
-
-
-************
-Potential bug:
-
-       We would need to decode the shortname before we lookup members?
-       
-       Maybe not.
-
-interface I {
-       void A ();
-}
-
-class X : I {
-       void I.A ();
-}

 
 

-class Y : X, I {
-       void I.A () {}
-}
+* Anonymous Methods
+===================

 
 

+In EmitAnonymousHelperClasses we set the "NeedThis" parameter of all
+the roots, but this is not necessary.  We should track the
+"HaveCapturedFields" on a per-ScopeInfo basis, and only set the
+HaveCapturedFields on the proper roots, instead of all the roots.

 
 
 
 

-*************