Changes in src/GenPoly/Specialize.cc [68fe077a:623ecf3]

File:

• src/GenPoly/Specialize.cc (modified) (3 diffs)

src/GenPoly/Specialize.cc

@@ -77 +77 @@
         }
 
+        /// True if both types have the same structure, but not necessarily the same types.
+        /// That is, either both types are tuple types with the same size (recursively), or
+        /// both are not tuple types.
+        bool matchingTupleStructure( Type * t1, Type * t2 ) {
+                TupleType * tuple1 = dynamic_cast< TupleType * >( t1 );
+                TupleType * tuple2 = dynamic_cast< TupleType * >( t2 );
+                if ( tuple1 && tuple2 ) {
+                        if ( tuple1->size() != tuple2->size() ) return false;
+                        for ( auto types : group_iterate( tuple1->get_types(), tuple2->get_types() ) ) {
+                                if ( ! matchingTupleStructure( std::get<0>( types ), std::get<1>( types ) ) ) return false;
+                        }
+                        return true;
+                } else if ( ! tuple1 && ! tuple2 ) return true;
+                return false;
+        }
+
         bool needsTupleSpecialization( Type *formalType, Type *actualType, TypeSubstitution *env ) {
-                if ( FunctionType * ftype = getFunctionType( formalType ) ) {
-                        return ftype->isTtype();
+                // Needs tuple specialization if the structure of the formal type and actual type do not match.
+                // This is the case if the formal type has ttype polymorphism, or if the structure  of tuple types
+                // between the function do not match exactly.
+                if ( FunctionType * fftype = getFunctionType( formalType ) ) {
+                        if ( fftype->isTtype() ) return true;
+                        FunctionType * aftype = getFunctionType( actualType );
+                        assertf( aftype, "formal type is a function type, but actual type is not." );
+                        if ( fftype->get_parameters().size() != aftype->get_parameters().size() ) return true;
+                        for ( auto params : group_iterate( fftype->get_parameters(), aftype->get_parameters() ) ) {
+                                DeclarationWithType * formal = std::get<0>(params);
+                                DeclarationWithType * actual = std::get<1>(params);
+                                if ( ! matchingTupleStructure( formal->get_type(), actual->get_type() ) ) return true;
+                        }
                 }
                 return false;
@@ -110 +137 @@
         }
 
-        /// restructures arg to match the structure of a single formal parameter. Assumes that atomic types are compatible (as the Resolver should have ensured this)
-        template< typename OutIterator >
-        void matchOneFormal( Expression * arg, unsigned & idx, Type * formal, OutIterator out ) {
-                if ( TupleType * tupleType = dynamic_cast< TupleType * >( formal ) ) {
+        /// restructures the arguments to match the structure of the formal parameters of the actual function.
+        /// [begin, end) are the exploded arguments.
+        template< typename Iterator, typename OutIterator >
+        void structureArg( Type * type, Iterator & begin, Iterator end, OutIterator out ) {
+                if ( TupleType * tuple = dynamic_cast< TupleType * >( type ) ) {
                         std::list< Expression * > exprs;
-                        for ( Type * t : *tupleType ) {
-                                matchOneFormal( arg, idx, t, back_inserter( exprs ) );
+                        for ( Type * t : *tuple ) {
+                                structureArg( t, begin, end, back_inserter( exprs ) );
                         }
                         *out++ = new TupleExpr( exprs );
                 } else {
-                        *out++ = new TupleIndexExpr( arg->clone(), idx++ );
-                }
-        }
-
-        /// restructures the ttype argument to match the structure of the formal parameters of the actual function.
-        /// [begin, end) are the formal parameters.
-        /// args is the list of arguments currently given to the actual function, the last of which needs to be restructured.
-        template< typename Iterator, typename OutIterator >
-        void fixLastArg( Expression * last, Iterator begin, Iterator end, OutIterator out ) {
-                if ( Tuples::isTtype( last->get_result() ) ) {
-                        *out++ = last;
-                } else {
-                        // safe_dynamic_cast for the assertion
-                        safe_dynamic_cast< TupleType * >( last->get_result() );
-                        unsigned idx = 0;
-                        for ( ; begin != end; ++begin ) {
-                                DeclarationWithType * formal = *begin;
-                                Type * formalType = formal->get_type();
-                                matchOneFormal( last, idx, formalType, out );
-                        }
-                        delete last;
-                }
+                        assertf( begin != end, "reached the end of the arguments while structuring" );
+                        *out++ = *begin++;
+                }
+        }
+
+        /// explode assuming simple cases: either type is pure tuple (but not tuple expr) or type is non-tuple.
+        template< typename OutputIterator >
+        void explodeSimple( Expression * expr, OutputIterator out ) {
+                if ( TupleType * tupleType = dynamic_cast< TupleType * > ( expr->get_result() ) ) {
+                        // tuple type, recursively index into its components
+                        for ( unsigned int i = 0; i < tupleType->size(); i++ ) {
+                                explodeSimple( new TupleIndexExpr( expr->clone(), i ), out );
+                        }
+                        delete expr;
+                } else {
+                        // non-tuple type - output a clone of the expression
+                        *out++ = expr;
+                }
+        }
+
+        struct EnvTrimmer : public Visitor {
+                TypeSubstitution * env, * newEnv;
+                EnvTrimmer( TypeSubstitution * env, TypeSubstitution * newEnv ) : env( env ), newEnv( newEnv ){}
+                virtual void visit( TypeDecl * tyDecl ) {
+                        // transfer known bindings for seen type variables
+                        if ( Type * t = env->lookup( tyDecl->get_name() ) ) {
+                                newEnv->add( tyDecl->get_name(), t );
+                        }
+                }
+        };
+
+        /// reduce environment to just the parts that are referenced in a given expression
+        TypeSubstitution * trimEnv( ApplicationExpr * expr, TypeSubstitution * env ) {
+                if ( env ) {
+                        TypeSubstitution * newEnv = new TypeSubstitution();
+                        EnvTrimmer trimmer( env, newEnv );
+                        expr->accept( trimmer );
+                        return newEnv;
+                }
+                return nullptr;
         }
 
@@ -173 +219 @@
                 std::list< DeclarationWithType * >::iterator actualBegin = actualType->get_parameters().begin();
                 std::list< DeclarationWithType * >::iterator actualEnd = actualType->get_parameters().end();
-                std::list< DeclarationWithType * >::iterator formalBegin = funType->get_parameters().begin();
-                std::list< DeclarationWithType * >::iterator formalEnd = funType->get_parameters().end();
-
+
+                std::list< Expression * > args;
                 for ( DeclarationWithType* param : thunkFunc->get_functionType()->get_parameters() ) {
-                        // walk the parameters to the actual function alongside the parameters to the thunk to find the location where the ttype parameter begins to satisfy parameters in the actual function.
+                        // name each thunk parameter and explode it - these are then threaded back into the actual function call.
                         param->set_name( paramNamer.newName() );
-                        assertf( formalBegin != formalEnd, "Reached end of formal parameters before finding ttype parameter" );
-                        if ( Tuples::isTtype((*formalBegin)->get_type()) ) {
-                                fixLastArg( new VariableExpr( param ), actualBegin, actualEnd, back_inserter( appExpr->get_args() ) );
-                                break;
-                        }
-                        assertf( actualBegin != actualEnd, "reached end of actual function's arguments before finding ttype parameter" );
-                        ++actualBegin;
-                        ++formalBegin;
-
-                        appExpr->get_args().push_back( new VariableExpr( param ) );
-                } // for
-                appExpr->set_env( maybeClone( env ) );
+                        explodeSimple( new VariableExpr( param ), back_inserter( args ) );
+                }
+
+                // walk parameters to the actual function alongside the exploded thunk parameters and restructure the arguments to match the actual parameters.
+                std::list< Expression * >::iterator argBegin = args.begin(), argEnd = args.end();
+                for ( ; actualBegin != actualEnd; ++actualBegin ) {
+                        structureArg( (*actualBegin)->get_type(), argBegin, argEnd, back_inserter( appExpr->get_args() ) );
+                }
+
+                appExpr->set_env( trimEnv( appExpr, env ) );
                 if ( inferParams ) {
                         appExpr->get_inferParams() = *inferParams;