X-Git-Url: http://wien.tomnetworks.com/gitweb/?a=blobdiff_plain;f=mcs%2Fmcs%2FTODO;h=1abb0382b7bdc02b935afae54b8f06a9774130fe;hb=728847d662a3b9af74f32f5466f0287267b311e7;hp=c6ec5c3e359dd186736d6f49c45bfd89a2317e6e;hpb=147ded2fb63d2575a941a25582a177ed9cccd1a6;p=mono.git diff --git a/mcs/mcs/TODO b/mcs/mcs/TODO index c6ec5c3e359..1abb0382b7b 100644 --- a/mcs/mcs/TODO +++ b/mcs/mcs/TODO @@ -1,182 +1,112 @@ +=========================================== -Notes on memory allocation --------------------------- +* Value Parameter - A run of the AllocationProfile shows that the compiler allocates roughly - 30 megabytes of strings. From those, 20 megabytes come from - LookupType. + 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: - See the notes on current_container problems below on memory usage. + Section 9.3 in the latest spec. -GetNamespaces -------------- - - Obtaining the list of namespaces is an expensive process because - Reflection.Emit does not provide a quick way of pulling the data out, - and it is too slow to load it. - - Calling GetNamespaces on my machine (1Ghz): - - * Takes half a second with the standard assemblies (corlib + System); - Fetching the types from it takes 0.0028650 seconds. - - * Loading the top 10 largest assemblies we ship with Mono makes MCS take - 8 seconds to startup the first time, subsequent invocations take 2 seconds. - - Fetching all the types (Assembly.GetTypes ()) for all the assemblies takes - 0.0069170 seconds. - - So pulling all the types takes very little time, maybe we should look into our - Hashtable implementation to make it more optimal. - - This prohibits re-writting SimpleName to take advantage of - knowing the namespace names in advance. Knowing the namespaces in advance - would allow me to reduce the guesswork in which we are currently engaged - to find a type definition. -LookupTypeReflection: ---------------------- +Large project: +-------------- - With something like `System.Object', LookupTypeReflection will be called - twice: once to find out that `System' is not a type and once - for System.Object. +New +--- - This is required because System.Reflection requires that the type/nested types are - not separated by a dot but by a plus sign. + It would be nice to optimize the case of: - A nested class would be My+Class (My being the toplevel, Class the nested one). + Method (new ValueType ()) - It is interesting to look at the most called lookups when bootstrapping MCS: + 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. - 647 LTR: ArrayList - 713 LTR: System.Globalization - 822 LTR: System.Object+Expression - 904 LTR: Mono.CSharp.ArrayList - 976 LTR: System.Runtime.CompilerServices - 999 LTR: Type - 1118 LTR: System.Runtime - 1208 LTR: Mono.CSharp.Type - 1373 LTR: Mono.Languages - 1599 LTR: System.Diagnostics - 2036 LTR: System.Text - 2302 LTR: System.Reflection.Emit - 2515 LTR: System.Collections - 4527 LTR: System.Reflection - 22273 LTR: Mono.CSharp - 24245 LTR: System - 27005 LTR: Mono +NEW NOTES: +---------- - Analysis: - The top 9 lookups are done for things which are not types. + ImplicitStandardConversionExists and ImplicitStandardConversion + should always be the same, but there are a few diverging lines that + must be studied: - Mono.CSharp.Type happens to be a common lookup: the class Type - used heavily in the compiler in the default namespace. + if (expr_type == target_type && !(expr is NullLiteral)) + return expr; - RED FLAG: + vs: - Then `Type' is looked up alone a lot of the time, this happens - in parameter declarations and am not entirely sure that this is - correct (FindType will pass to LookupInterfaceOrClass a the current_type.FullName, - which for some reason is null!). This seems to be a problem with a lost - piece of context during FindType. + if (expr_type == target_type) + return true; - System.Object is also used a lot as a toplevel class, and we assume it will - have children, we should just shortcut this. - - A cache: - - Adding a cache and adding a catch for `System.Object' to flag that it wont be the - root of a hierarchy reduced the MCS bootstrap time from 10.22 seconds to 8.90 seconds. - - This cache is currently enabled with SIMPLE_SPEEDUP in typemanager.cs. Memory consumption - went down from 74 megs to 65 megs with this change. - -Ideas: ------- +**************************************************************************************** +* +* The information on the rest of this file is mostly outdated, and its kept here for +* historical reasons +* +**************************************************************************************** + +Error Reporting: +---------------- - 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. + * Make yyerror show a nice syntax error, instead of the current mess. -The use of DottedName ---------------------- +Optimization ideas +------------------ - We could probably use a different system to represent names, like this: + 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. - class Name { - string simplename; - Name parent; - } + We create too many Arraylists; When we know the size, we should create + an array; - So `System.ComponentModel' becomes: + During parsing we use arraylists to accumulate data, like this: - x: (System, null) - y: (ComponentModel, x) + thing: + + thing_list + : thing { $$ =new ArrayList (); $$.Add ($1); } + | thing_list thing { ArrayList a = $1; a.Add ($2); $$ = a; } - The problem is that we would still need to construct the name to pass to - GetType. + We probably could start using "Pairs" there: -current_container/current_namespace and the DeclSpace ------------------------------------------------------ + thing_list + : thing { $$ = new Pair ($1, null); } + | thing_list thing { Pair p = $1; $$ = new Pair ($2, $1); } - We are storing fully qualified names in the DeclSpace instead of the node, - this is because `current_namespace' (Namepsace) is not a DeclSpace like - `current_container'. - The reason for storing the full names today is this: +EmitContext.ResolveTypeTree +--------------------------- - namespace X { - class Y { - } - } + We should investigate its usage. The problem is that by default + this will be set when calling FindType, that triggers a more expensive + lookup. - namespace A { - class Y { - } - } + 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. - The problem is that we only use the namespace stack to track the "prefix" - for typecontainers, but they are not typecontainers themselves, so we have - to use fully qualified names, because both A.X and A.Y would be entered - in the toplevel type container. If we use the short names, there would be - a name clash. +DeclareLocal audit +------------------ - To fix this problem, we have to make namespaces DeclSpaces. + DeclareLocal is used in various statements. The audit should be done + in two steps: - The full size, contrasted with the size that could be stored is: - corlib: - Size of strings held: 368901 - Size of strings short: 147863 + * Identify all the declare locals. - System: - Size of strings held: 212677 - Size of strings short: 97521 - - System.XML: - Size of strings held: 128055 - Size of strings short: 35782 - - System.Data: - Size of strings held: 117896 - Size of strings short: 36153 - - System.Web: - Size of strings held: 194527 - Size of strings short: 58064 - - System.Windows.Forms: - Size of strings held: 220495 - Size of strings short: 64923 + * Identify its uses. - -TODO: + * Find if we can make wrapper functions for all of them. - 1. Create a "partial" emit context for each TypeContainer.. + Then we can move DeclareLocal into a helper class. - 2. EmitContext should be partially constructed. No IL Generator. + This is required to fix foreach in iterators. - interface_type review. +Ideas: +------ - parameter_array, line 952: `note: must be a single dimension array type'. Validate this + 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. Dead Code Elimination bugs: --------------------------- @@ -185,30 +115,13 @@ Dead Code Elimination bugs: Major tasks: ------------ - - Pinned and volatile require type modifiers that can not be encoded - with Reflection.Emit. - Properties and 17.6.3: Finish it. - Implement base indexer access. - readonly variables and ref/out BUGS ---- -* Check for Final when overriding, if the parent is Final, then we cant - allow an override. - -* Interface indexers - - I have not figured out why the Microsoft version puts an - `instance' attribute, and I am not generating this `instance' attribute. - - Explanation: The reason for the `instance' attribute on - indexers is that indexers only apply to instances - * Break/Continue statements A finally block should reset the InLoop/LoopBegin/LoopEnd, as @@ -219,13 +132,6 @@ BUGS They should transfer control to the finally block if inside a try/catch block. -* Method Registration and error CS111 - - The way we use the method registration to signal 111 is wrong. - - Method registration should only be used to register methodbuilders, - we need an alternate method of checking for duplicates. - * > // CSC sets beforefieldinit > class X { @@ -240,11 +146,6 @@ PENDING TASKS * Merge test 89 and test-34 -* Revisit - - Primary-expression, as it has now been split into - non-array-creation-expression and array-creation-expression. - * Code cleanup The information when registering a method in InternalParameters @@ -254,12 +155,6 @@ PENDING TASKS 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 - * Merge tree.cs, rootcontext.cs OPTIMIZATIONS @@ -283,38 +178,11 @@ OPTIMIZATIONS The only pending problem is that the code that implements Aliases is on TypeContainer, and probably should go in DeclSpace. -* Use of local temporary in UnaryMutator - - We should get rid of the Localtemporary there for some cases - - This turns out to be very complex, at least for the post-version, - because this case: - - a = i++ - - To produce optimal code, it is necessary for UnaryMutator to know - that it is being assigned to a variable (the way the stack is laid - out using dup requires the store to happen inside UnaryMutator). - -* 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. - * 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 @@ -323,12 +191,6 @@ OPTIMIZATIONS * 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, @@ -359,8 +221,3 @@ RECOMMENDATIONS 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. -