source: src/GenPoly/InstantiateGeneric.cc @ 5bf4712

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// InstantiateGeneric.cc --
//
// Author           : Aaron B. Moss
// Created On       : Wed Nov 11 14:55:01 2015
// Last Modified By : Aaron B. Moss
// Last Modified On : Wed Nov 11 14:55:01 2015
// Update Count     : 1
//

#include <list>
#include <map>
#include <string>
#include <utility>
#include <vector>

#include "InstantiateGeneric.h"
#include "DeclMutator.h"

#include "ResolvExpr/typeops.h"
#include "SymTab/Indexer.h"
#include "SynTree/Declaration.h"
#include "SynTree/Mutator.h"
#include "SynTree/Statement.h"
#include "SynTree/Type.h"
#include "SynTree/TypeSubstitution.h"

#include "UniqueName.h"
#include "utility.h"

namespace GenPoly {

        /// Key for a unique concrete type; generic base type paired with type parameter list
        struct ConcreteType {
                ConcreteType() : base(NULL), params() {}

                ConcreteType(AggregateDecl *_base, const std::list< Type* >& _params) : base(_base), params() { cloneAll(_params, params); }

                ConcreteType(const ConcreteType& that) : base(that.base), params() { cloneAll(that.params, params); }

                /// Extracts types from a list of TypeExpr*
                ConcreteType(AggregateDecl *_base, const std::list< TypeExpr* >& _params) : base(_base), params() {
                        for ( std::list< TypeExpr* >::const_iterator param = _params.begin(); param != _params.end(); ++param ) {
                                params.push_back( (*param)->get_type()->clone() );
                        }
                }

                ConcreteType& operator= (const ConcreteType& that) {
                        deleteAll( params );
                        params.clear();

                        base = that.base;
                        cloneAll( that.params, params );

                        return *this;
                }

                ~ConcreteType() { deleteAll( params ); }

                bool operator== (const ConcreteType& that) const {
                        if ( base != that.base ) return false;

                        SymTab::Indexer dummy;
                        if ( params.size() != that.params.size() ) return false;
                        for ( std::list< Type* >::const_iterator it = params.begin(), jt = that.params.begin(); it != params.end(); ++it, ++jt ) {
                                if ( ! ResolvExpr::typesCompatible( *it, *jt, dummy ) ) return false;
                        }
                        return true;
                }

                AggregateDecl *base;        ///< Base generic type
                std::list< Type* > params;  ///< Instantiation parameters
        };

        /// Maps a concrete type to the instantiated struct type, accounting for scope
        class InstantiationMap {
                /// Instantiation of a generic type, with key information to find it
                struct Instantiation {
                        ConcreteType key;     ///< Instantiation parameters for this type
                        AggregateDecl *decl;  ///< Declaration of the instantiated generic type

                        Instantiation() : key(), decl(0) {}
                        Instantiation(const ConcreteType &_key, AggregateDecl *_decl) : key(_key), decl(_decl) {}
                };
                /// Map of generic types to instantiations of them
                typedef std::map< AggregateDecl*, std::vector< Instantiation > > Scope;

                std::vector< Scope > scopes;  ///< list of scopes, from outermost to innermost

        public:
                /// Starts a new scope
                void beginScope() {
                        Scope scope;
                        scopes.push_back(scope);
                }

                /// Ends a scope
                void endScope() {
                        scopes.pop_back();
                }

                /// Default constructor initializes with one scope
                InstantiationMap() { beginScope(); }

        private:
                /// Gets the declaration for the concrete instantiation of this type, assuming it has already been instantiated in the current scope.
                /// Returns NULL on none such.
                AggregateDecl* lookup( AggregateDecl *generic, const std::list< TypeExpr* >& params ) {
                        ConcreteType key(generic, params);
                        // scan scopes from innermost out
                        for ( std::vector< Scope >::const_reverse_iterator scope = scopes.rbegin(); scope != scopes.rend(); ++scope ) {
                                // skip scope if no instantiations of this generic type
                                Scope::const_iterator insts = scope->find( generic );
                                if ( insts == scope->end() ) continue;
                                // look through instantiations for matches to concrete type
                                for ( std::vector< Instantiation >::const_iterator inst = insts->second.begin(); inst != insts->second.end(); ++inst ) {
                                        if ( inst->key == key ) return inst->decl;
                                }
                        }
                        // no matching instantiation found
                        return NULL;
                }
        public:
                StructDecl* lookup( StructInstType *inst, const std::list< TypeExpr* > &typeSubs ) { return (StructDecl*)lookup( inst->get_baseStruct(), typeSubs ); }
                UnionDecl* lookup( UnionInstType *inst, const std::list< TypeExpr* > &typeSubs ) { return (UnionDecl*)lookup( inst->get_baseUnion(), typeSubs ); }

        private:
                /// Adds a declaration for a concrete type to the current scope
                void insert( AggregateDecl *generic, const std::list< TypeExpr* > &params, AggregateDecl *decl ) {
                        ConcreteType key(generic, params);
                        scopes.back()[generic].push_back( Instantiation( key, decl ) );
                }
        public:
                void insert( StructInstType *inst, const std::list< TypeExpr* > &typeSubs, StructDecl *decl ) { insert( inst->get_baseStruct(), typeSubs, decl ); }
                void insert( UnionInstType *inst, const std::list< TypeExpr* > &typeSubs, UnionDecl *decl ) { insert( inst->get_baseUnion(), typeSubs, decl ); }
        };

        /// Mutator pass that replaces concrete instantiations of generic types with actual struct declarations, scoped appropriately
        class Instantiate : public DeclMutator {
                InstantiationMap instantiations;
                UniqueName typeNamer;

        public:
                Instantiate() : DeclMutator(), instantiations(), typeNamer("_conc_") {}

//              virtual Declaration* mutate( StructDecl *aggregateDecl );
//              virtual Declaration* mutate( UnionDecl *aggregateDecl );

                virtual Type* mutate( StructInstType *inst );
                virtual Type* mutate( UnionInstType *inst );
                
                virtual void doBeginScope();
                virtual void doEndScope();
        };
        
        void instantiateGeneric( std::list< Declaration* >& translationUnit ) {
                Instantiate instantiator;
                instantiator.mutateDeclarationList( translationUnit );
        }

        /// Makes substitutions of params into baseParams; returns true if all parameters substituted for a concrete type
        bool makeSubstitutions( const std::list< TypeDecl* >& baseParams, const std::list< Expression* >& params, std::list< TypeExpr* >& out ) {
                bool allConcrete = true;  // will finish the substitution list even if they're not all concrete

                // substitute concrete types for given parameters, and incomplete types for placeholders
                std::list< TypeDecl* >::const_iterator baseParam = baseParams.begin();
                std::list< Expression* >::const_iterator param = params.begin();
                for ( ; baseParam != baseParams.end() && param != params.end(); ++baseParam, ++param ) {
                        switch ( (*baseParam)->get_kind() ) {
                        case TypeDecl::Any: {   // any type is a valid substitution here; complete types can be used to instantiate generics
                                TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
                                assert(paramType && "Aggregate parameters should be type expressions");
                                out.push_back( paramType->clone() );
                                // check that the substituted type isn't a type variable itself
                                if ( dynamic_cast< TypeInstType* >( paramType->get_type() ) ) {
                                        allConcrete = false;
                                }
                                break;
                        }
                        case TypeDecl::Dtype:  // dtype can be consistently replaced with void [only pointers, which become void*]
                                out.push_back( new TypeExpr( new VoidType( Type::Qualifiers() ) ) );
                                break;
                        case TypeDecl::Ftype:  // pointer-to-ftype can be consistently replaced with void (*)(void) [similar to dtype]
                                out.push_back( new TypeExpr( new FunctionType( Type::Qualifiers(), false ) ) );
                                break;
                        }
                }

                // if not enough parameters given, substitute remaining incomplete types for placeholders
                for ( ; baseParam != baseParams.end(); ++baseParam ) {
                        switch ( (*baseParam)->get_kind() ) {
                        case TypeDecl::Any:    // no more substitutions here, fail early
                                return false;
                        case TypeDecl::Dtype:  // dtype can be consistently replaced with void [only pointers, which become void*]
                                out.push_back( new TypeExpr( new VoidType( Type::Qualifiers() ) ) );
                                break;
                        case TypeDecl::Ftype:  // pointer-to-ftype can be consistently replaced with void (*)(void) [similar to dtype]
                                out.push_back( new TypeExpr( new FunctionType( Type::Qualifiers(), false ) ) );
                                break;
                        }
                }

                return allConcrete;
        }
        
        /// Substitutes types of members of in according to baseParams => typeSubs, appending the result to out
        void substituteMembers( const std::list< Declaration* >& in, const std::list< TypeDecl* >& baseParams, const std::list< TypeExpr* >& typeSubs, 
                                                    std::list< Declaration* >& out ) {
                // substitute types into new members
                TypeSubstitution subs( baseParams.begin(), baseParams.end(), typeSubs.begin() );
                for ( std::list< Declaration* >::const_iterator member = in.begin(); member != in.end(); ++member ) {
                        Declaration *newMember = (*member)->clone();
                        subs.apply(newMember);
                        out.push_back( newMember );
                }
        }

        Type* Instantiate::mutate( StructInstType *inst ) {
                // mutate subtypes
                Type *mutated = Mutator::mutate( inst );
                inst = dynamic_cast< StructInstType* >( mutated );
                if ( ! inst ) return mutated;

                // exit early if no need for further mutation
                if ( inst->get_parameters().empty() ) return inst;
                assert( inst->get_baseParameters() && "Base struct has parameters" );

                // check if type can be concretely instantiated; put substitutions into typeSubs
                std::list< TypeExpr* > typeSubs;
                if ( ! makeSubstitutions( *inst->get_baseParameters(), inst->get_parameters(), typeSubs ) ) {
                        deleteAll( typeSubs );
                        return inst;
                }
                
                // make concrete instantiation of generic type
                StructDecl *concDecl = instantiations.lookup( inst, typeSubs );
                if ( ! concDecl ) {
                        // set concDecl to new type, insert type declaration into statements to add
                        concDecl = new StructDecl( typeNamer.newName( inst->get_name() ) );
                        substituteMembers( inst->get_baseStruct()->get_members(), *inst->get_baseParameters(), typeSubs,        concDecl->get_members() );
                        DeclMutator::addDeclaration( concDecl );
                        instantiations.insert( inst, typeSubs, concDecl );
                }
                StructInstType *newInst = new StructInstType( inst->get_qualifiers(), concDecl->get_name() );
                newInst->set_baseStruct( concDecl );

                deleteAll( typeSubs );
                delete inst;
                return newInst;
        }
        
        Type* Instantiate::mutate( UnionInstType *inst ) {
                // mutate subtypes
                Type *mutated = Mutator::mutate( inst );
                inst = dynamic_cast< UnionInstType* >( mutated );
                if ( ! inst ) return mutated;

                // exit early if no need for further mutation
                if ( inst->get_parameters().empty() ) return inst;
                assert( inst->get_baseParameters() && "Base union has parameters" );

                // check if type can be concretely instantiated; put substitutions into typeSubs
                std::list< TypeExpr* > typeSubs;
                if ( ! makeSubstitutions( *inst->get_baseParameters(), inst->get_parameters(), typeSubs ) ) {
                        deleteAll( typeSubs );
                        return inst;
                }
                
                // make concrete instantiation of generic type
                UnionDecl *concDecl = instantiations.lookup( inst, typeSubs );
                if ( ! concDecl ) {
                        // set concDecl to new type, insert type declaration into statements to add
                        concDecl = new UnionDecl( typeNamer.newName( inst->get_name() ) );
                        substituteMembers( inst->get_baseUnion()->get_members(), *inst->get_baseParameters(), typeSubs, concDecl->get_members() );
                        DeclMutator::addDeclaration( concDecl );
                        instantiations.insert( inst, typeSubs, concDecl );
                }
                UnionInstType *newInst = new UnionInstType( inst->get_qualifiers(), concDecl->get_name() );
                newInst->set_baseUnion( concDecl );

                deleteAll( typeSubs );
                delete inst;
                return newInst;
        }
        
        void Instantiate::doBeginScope() {
                DeclMutator::doBeginScope();
                // push a new concrete type scope
                instantiations.beginScope();
        }

        void Instantiate::doEndScope() {
                DeclMutator::doEndScope();
                // pop the last concrete type scope
                instantiations.endScope();
        }
        
}  // namespace GenPoly

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //