//
// 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.
//
// Autogen.cc --
//
// Author           : Rob Schluntz
// Created On       : Thu Mar 03 15:45:56 2016
// Last Modified By : Andrew Beach
// Last Modified On : Fri Jul 14 16:41:00 2017
// Update Count     : 62
//

#include "Autogen.h"

#include <algorithm>               // for count_if
#include <cassert>                 // for strict_dynamic_cast, assert, assertf
#include <iterator>                // for back_insert_iterator, back_inserter
#include <list>                    // for list, _List_iterator, list<>::iter...
#include <set>                     // for set, _Rb_tree_const_iterator
#include <utility>                 // for pair
#include <vector>                  // for vector

#include "AddVisit.h"              // for addVisit
#include "CodeGen/OperatorTable.h" // for isCtorDtor, isCtorDtorAssign
#include "Common/PassVisitor.h"    // for PassVisitor
#include "Common/ScopedMap.h"      // for ScopedMap<>::const_iterator, Scope...
#include "Common/utility.h"        // for cloneAll, operator+
#include "GenPoly/ScopedSet.h"     // for ScopedSet, ScopedSet<>::iterator
#include "InitTweak/GenInit.h"     // for fixReturnStatements
#include "ResolvExpr/Resolver.h"   // for resolveDecl
#include "SymTab/Mangler.h"        // for Mangler
#include "SynTree/Attribute.h"     // For Attribute
#include "SynTree/Mutator.h"       // for maybeMutate
#include "SynTree/Statement.h"     // for CompoundStmt, ReturnStmt, ExprStmt
#include "SynTree/Type.h"          // for FunctionType, Type, TypeInstType
#include "SynTree/Visitor.h"       // for maybeAccept, Visitor, acceptAll

class Attribute;

namespace SymTab {
	Type * SizeType = 0;
	typedef ScopedMap< std::string, bool > TypeMap;

	/// Data used to generate functions generically. Specifically, the name of the generated function, a function which generates the routine protoype, and a map which contains data to determine whether a function should be generated.
	struct FuncData {
		typedef FunctionType * (*TypeGen)( Type * );
		FuncData( const std::string & fname, const TypeGen & genType, TypeMap & map ) : fname( fname ), genType( genType ), map( map ) {}
		std::string fname;
		TypeGen genType;
		TypeMap & map;
	};

	struct AutogenerateRoutines final : public WithDeclsToAdd, public WithVisitorRef<AutogenerateRoutines>, public WithGuards, public WithShortCircuiting {
		AutogenerateRoutines();

		void previsit( EnumDecl * enumDecl );
		void previsit( StructDecl * structDecl );
		void previsit( UnionDecl * structDecl );
		void previsit( TypeDecl * typeDecl );
		void previsit( TraitDecl * traitDecl );
		void previsit( FunctionDecl * functionDecl );

		void previsit( FunctionType * ftype );
		void previsit( PointerType * ptype );

		void previsit( CompoundStmt * compoundStmt );

	  private:
		GenPoly::ScopedSet< std::string > structsDone;
		unsigned int functionNesting = 0;     // current level of nested functions
		/// Note: the following maps could be ScopedSets, but it should be easier to work
		/// deleted functions in if they are maps, since the value false can be inserted
		/// at the current scope without affecting outer scopes or requiring copies.
		TypeMap copyable, assignable, constructable, destructable;
		std::vector< FuncData > data;
	};

	/// generates routines for tuple types.
	struct AutogenTupleRoutines : public WithDeclsToAdd, public WithVisitorRef<AutogenTupleRoutines>, public WithGuards, public WithShortCircuiting {
		void previsit( FunctionDecl *functionDecl );

		void postvisit( TupleType *tupleType );

		void previsit( CompoundStmt *compoundStmt );

	  private:
		unsigned int functionNesting = 0;     // current level of nested functions
		GenPoly::ScopedSet< std::string > seenTuples;
	};

	void autogenerateRoutines( std::list< Declaration * > &translationUnit ) {
		PassVisitor<AutogenerateRoutines> generator;
		acceptAll( translationUnit, generator );

		// needs to be done separately because AutogenerateRoutines skips types that appear as function arguments, etc.
		// AutogenTupleRoutines tupleGenerator;
		// acceptAll( translationUnit, tupleGenerator );
	}

	bool isUnnamedBitfield( ObjectDecl * obj ) {
		return obj != nullptr && obj->get_name() == "" && obj->get_bitfieldWidth() != nullptr;
	}

	/// inserts a forward declaration for functionDecl into declsToAdd
	void addForwardDecl( FunctionDecl * functionDecl, std::list< Declaration * > & declsToAdd ) {
		FunctionDecl * decl = functionDecl->clone();
		delete decl->get_statements();
		decl->set_statements( nullptr );
		declsToAdd.push_back( decl );
		decl->fixUniqueId();
	}

	/// given type T, generate type of default ctor/dtor, i.e. function type void (*) (T *)
	FunctionType * genDefaultType( Type * paramType ) {
		FunctionType *ftype = new FunctionType( Type::Qualifiers(), false );
		ObjectDecl *dstParam = new ObjectDecl( "_dst", Type::StorageClasses(), LinkageSpec::Cforall, nullptr, new ReferenceType( Type::Qualifiers(), paramType->clone() ), nullptr );
		ftype->get_parameters().push_back( dstParam );
		return ftype;
	}

	/// given type T, generate type of copy ctor, i.e. function type void (*) (T *, T)
	FunctionType * genCopyType( Type * paramType ) {
		FunctionType *ftype = genDefaultType( paramType );
		ObjectDecl *srcParam = new ObjectDecl( "_src", Type::StorageClasses(), LinkageSpec::Cforall, nullptr, paramType->clone(), nullptr );
		ftype->get_parameters().push_back( srcParam );
		return ftype;
	}

	/// given type T, generate type of assignment, i.e. function type T (*) (T *, T)
	FunctionType * genAssignType( Type * paramType ) {
		FunctionType *ftype = genCopyType( paramType );
		ObjectDecl *returnVal = new ObjectDecl( "_ret", Type::StorageClasses(), LinkageSpec::Cforall, nullptr, paramType->clone(), nullptr );
		ftype->get_returnVals().push_back( returnVal );
		return ftype;
	}

	/// generate a function decl from a name and type. Nesting depth determines whether
	/// the declaration is static or not; optional paramter determines if declaration is intrinsic
	FunctionDecl * genFunc( const std::string & fname, FunctionType * ftype, unsigned int functionNesting, bool isIntrinsic = false  ) {
		// Routines at global scope marked "static" to prevent multiple definitions in separate translation units
		// because each unit generates copies of the default routines for each aggregate.
		Type::StorageClasses scs = functionNesting > 0 ? Type::StorageClasses() : Type::StorageClasses( Type::Static );
		LinkageSpec::Spec spec = isIntrinsic ? LinkageSpec::Intrinsic : LinkageSpec::AutoGen;
		FunctionDecl * decl = new FunctionDecl( fname, scs, spec, ftype, new CompoundStmt( noLabels ),
												std::list< Attribute * >(), Type::FuncSpecifiers( Type::Inline ) );
		decl->fixUniqueId();
		return decl;
	}

	/// inserts base type of first argument into map if pred(funcDecl) is true
	void insert( FunctionDecl *funcDecl, TypeMap & map, FunctionDecl * (*pred)(Declaration *) ) {
		// insert type into constructable, etc. map if appropriate
		if ( pred( funcDecl ) ) {
			FunctionType * ftype = funcDecl->get_functionType();
			assert( ! ftype->get_parameters().empty() );
			Type * t = InitTweak::getPointerBase( ftype->get_parameters().front()->get_type() );
			assert( t );
			map.insert( Mangler::mangleType( t ), true );
		}
	}

	/// using map and t, determines if is constructable, etc.
	bool lookup( const TypeMap & map, Type * t ) {
		assertf( t, "Autogenerate lookup was given non-type: %s", toString( t ).c_str() );
		if ( dynamic_cast< PointerType * >( t ) ) {
			// will need more complicated checking if we want this to work with pointer types, since currently
			return true;
		} else if ( ArrayType * at = dynamic_cast< ArrayType * >( t ) ) {
			// an array's constructor, etc. is generated on the fly based on the base type's constructor, etc.
			return lookup( map, at->get_base() );
		}
		TypeMap::const_iterator it = map.find( Mangler::mangleType( t ) );
		if ( it != map.end() ) return it->second;
		// something that does not appear in the map is by default not constructable, etc.
		return false;
	}

	/// using map and aggr, examines each member to determine if constructor, etc. should be generated
	template<typename Container>
	bool shouldGenerate( const TypeMap & map, const Container & container ) {
		for ( Type * t : container ) {
			if ( ! lookup( map, t ) ) return false;
		}
		return true;
	}

	/// data structure for abstracting the generation of special functions
	template< typename OutputIterator, typename Container >
	struct FuncGenerator {
		const Container & container;
		Type *refType;
		unsigned int functionNesting;
		const std::list< TypeDecl* > & typeParams;
		OutputIterator out;
		FuncGenerator( const Container & container, Type *refType, unsigned int functionNesting, const std::list< TypeDecl* > & typeParams, OutputIterator out ) : container( container ), refType( refType ), functionNesting( functionNesting ), typeParams( typeParams ), out( out ) {}

		/// generates a function (?{}, ?=?, ^?{}) based on the data argument and members. If function is generated, inserts the type into the map.
		void gen( const FuncData & data, bool concurrent_type ) {
			if ( ! shouldGenerate( data.map, container ) ) return;
			FunctionType * ftype = data.genType( refType );

			if ( concurrent_type && CodeGen::isDestructor( data.fname ) ) {
				ftype->parameters.front()->get_type()->set_mutex( true );
			}

			cloneAll( typeParams, ftype->forall );
			*out++ = genFunc( data.fname, ftype, functionNesting );
			data.map.insert( Mangler::mangleType( refType ), true );
		}
	};

	template< typename OutputIterator, typename Container >
	FuncGenerator<OutputIterator, Container> makeFuncGenerator( const Container & container, Type *refType, unsigned int functionNesting, const std::list< TypeDecl* > & typeParams, OutputIterator out ) {
		return FuncGenerator<OutputIterator, Container>( container, refType, functionNesting, typeParams, out );
	}

	/// generates a single enumeration assignment expression
	ApplicationExpr * genEnumAssign( FunctionType * ftype, FunctionDecl * assignDecl ) {
		// enum copy construct and assignment is just C-style assignment.
		// this looks like a bad recursive call, but code gen will turn it into
		// a C-style assignment.
		// This happens before function pointer type conversion, so need to do it manually here
		// NOTE: ftype is not necessarily the functionType belonging to assignDecl - ftype is the
		// type of the function that this expression is being generated for (so that the correct
		// parameters) are using in the variable exprs
		assert( ftype->get_parameters().size() == 2 );
		ObjectDecl * dstParam = strict_dynamic_cast< ObjectDecl * >( ftype->get_parameters().front() );
		ObjectDecl * srcParam = strict_dynamic_cast< ObjectDecl * >( ftype->get_parameters().back() );

		VariableExpr * assignVarExpr = new VariableExpr( assignDecl );
		Type * assignVarExprType = assignVarExpr->get_result();
		assignVarExprType = new PointerType( Type::Qualifiers(), assignVarExprType );
		assignVarExpr->set_result( assignVarExprType );
		ApplicationExpr * assignExpr = new ApplicationExpr( assignVarExpr );
		assignExpr->get_args().push_back( new VariableExpr( dstParam ) );
		assignExpr->get_args().push_back( new VariableExpr( srcParam ) );
		return assignExpr;
	}

	// E ?=?(E volatile*, int),
	//   ?=?(E _Atomic volatile*, int);
	void makeEnumFunctions( EnumInstType *refType, unsigned int functionNesting, std::list< Declaration * > &declsToAdd ) {

		// T ?=?(E *, E);
		FunctionType *assignType = genAssignType( refType );

		// void ?{}(E *); void ^?{}(E *);
		FunctionType * ctorType = genDefaultType( refType->clone() );
		FunctionType * dtorType = genDefaultType( refType->clone() );

		// void ?{}(E *, E);
		FunctionType *copyCtorType = genCopyType( refType->clone() );

		// add unused attribute to parameters of default constructor and destructor
		ctorType->get_parameters().front()->get_attributes().push_back( new Attribute( "unused" ) );
		dtorType->get_parameters().front()->get_attributes().push_back( new Attribute( "unused" ) );

		// xxx - should we also generate void ?{}(E *, int) and E ?{}(E *, E)?
		// right now these cases work, but that might change.

		// xxx - Temporary: make these functions intrinsic so they codegen as C assignment.
		// Really they're something of a cross between instrinsic and autogen, so should
		// probably make a new linkage type
		FunctionDecl *assignDecl = genFunc( "?=?", assignType, functionNesting, true );
		FunctionDecl *ctorDecl = genFunc( "?{}", ctorType, functionNesting, true );
		FunctionDecl *copyCtorDecl = genFunc( "?{}", copyCtorType, functionNesting, true );
		FunctionDecl *dtorDecl = genFunc( "^?{}", dtorType, functionNesting, true );

		// body is either return stmt or expr stmt
		assignDecl->get_statements()->get_kids().push_back( new ReturnStmt( noLabels, genEnumAssign( assignType, assignDecl ) ) );
		copyCtorDecl->get_statements()->get_kids().push_back( new ExprStmt( noLabels, genEnumAssign( copyCtorType, assignDecl ) ) );

		declsToAdd.push_back( ctorDecl );
		declsToAdd.push_back( copyCtorDecl );
		declsToAdd.push_back( dtorDecl );
		declsToAdd.push_back( assignDecl ); // assignment should come last since it uses copy constructor in return
	}

	/// generates a single struct member operation (constructor call, destructor call, assignment call)
	void makeStructMemberOp( ObjectDecl * dstParam, Expression * src, DeclarationWithType * field, FunctionDecl * func, bool forward = true ) {
		InitTweak::InitExpander srcParam( src );

		// assign to destination
		Expression *dstselect = new MemberExpr( field, new CastExpr( new VariableExpr( dstParam ), strict_dynamic_cast< ReferenceType* >( dstParam->get_type() )->get_base()->clone() ) );
		genImplicitCall( srcParam, dstselect, func->get_name(), back_inserter( func->get_statements()->get_kids() ), field, forward );
	}

	/// generates the body of a struct function by iterating the struct members (via parameters) - generates default ctor, copy ctor, assignment, and dtor bodies, but NOT field ctor bodies
	template<typename Iterator>
	void makeStructFunctionBody( Iterator member, Iterator end, FunctionDecl * func, bool forward = true ) {
		for ( ; member != end; ++member ) {
			if ( DeclarationWithType *field = dynamic_cast< DeclarationWithType * >( *member ) ) { // otherwise some form of type declaration, e.g. Aggregate
				// query the type qualifiers of this field and skip assigning it if it is marked const.
				// If it is an array type, we need to strip off the array layers to find its qualifiers.
				Type * type = field->get_type();
				while ( ArrayType * at = dynamic_cast< ArrayType * >( type ) ) {
					type = at->get_base();
				}

				if ( type->get_const() && func->get_name() == "?=?" ) {
					// don't assign const members, but do construct/destruct
					continue;
				}

				if ( field->get_name() == "" ) {
					// don't assign to anonymous members
					// xxx - this is a temporary fix. Anonymous members tie into
					// our inheritance model. I think the correct way to handle this is to
					// cast the structure to the type of the member and let the resolver
					// figure out whether it's valid and have a pass afterwards that fixes
					// the assignment to use pointer arithmetic with the offset of the
					// member, much like how generic type members are handled.
					continue;
				}

				assert( ! func->get_functionType()->get_parameters().empty() );
				ObjectDecl * dstParam = dynamic_cast<ObjectDecl*>( func->get_functionType()->get_parameters().front() );
				ObjectDecl * srcParam = nullptr;
				if ( func->get_functionType()->get_parameters().size() == 2 ) {
					srcParam = dynamic_cast<ObjectDecl*>( func->get_functionType()->get_parameters().back() );
				}
				// srcParam may be NULL, in which case we have default ctor/dtor
				assert( dstParam );

				Expression *srcselect = srcParam ? new MemberExpr( field, new VariableExpr( srcParam ) ) : nullptr;
				makeStructMemberOp( dstParam, srcselect, field, func, forward );
			} // if
		} // for
	} // makeStructFunctionBody

	/// generate the body of a constructor which takes parameters that match fields, e.g.
	/// void ?{}(A *, int) and void?{}(A *, int, int) for a struct A which has two int fields.
	template<typename Iterator>
	void makeStructFieldCtorBody( Iterator member, Iterator end, FunctionDecl * func ) {
		FunctionType * ftype = func->get_functionType();
		std::list<DeclarationWithType*> & params = ftype->get_parameters();
		assert( params.size() >= 2 );  // should not call this function for default ctor, etc.

		// skip 'this' parameter
		ObjectDecl * dstParam = dynamic_cast<ObjectDecl*>( params.front() );
		assert( dstParam );
		std::list<DeclarationWithType*>::iterator parameter = params.begin()+1;
		for ( ; member != end; ++member ) {
			if ( DeclarationWithType * field = dynamic_cast<DeclarationWithType*>( *member ) ) {
				if ( isUnnamedBitfield( dynamic_cast< ObjectDecl * > ( field ) ) ) {
					// don't make a function whose parameter is an unnamed bitfield
					continue;
				} else if ( field->get_name() == "" ) {
					// don't assign to anonymous members
					// xxx - this is a temporary fix. Anonymous members tie into
					// our inheritance model. I think the correct way to handle this is to
					// cast the structure to the type of the member and let the resolver
					// figure out whether it's valid and have a pass afterwards that fixes
					// the assignment to use pointer arithmetic with the offset of the
					// member, much like how generic type members are handled.
					continue;
				} else if ( parameter != params.end() ) {
					// matching parameter, initialize field with copy ctor
					Expression *srcselect = new VariableExpr(*parameter);
					makeStructMemberOp( dstParam, srcselect, field, func );
					++parameter;
				} else {
					// no matching parameter, initialize field with default ctor
					makeStructMemberOp( dstParam, nullptr, field, func );
				}
			}
		}
	}

	Type * declToType( Declaration * decl ) {
		if ( DeclarationWithType * dwt = dynamic_cast< DeclarationWithType * >( decl ) ) {
			return dwt->get_type();
		}
		return nullptr;
	}

	/// generates struct constructors, destructor, and assignment functions
	void makeStructFunctions( StructDecl *aggregateDecl, StructInstType *refType, unsigned int functionNesting, std::list< Declaration * > & declsToAdd, const std::vector< FuncData > & data ) {
		// Builtins do not use autogeneration.
		if ( LinkageSpec::isBuiltin( aggregateDecl->get_linkage() ) ) {
			return;
		}

		// Make function polymorphic in same parameters as generic struct, if applicable
		const std::list< TypeDecl * > & typeParams = aggregateDecl->get_parameters(); // List of type variables to be placed on the generated functions

		// generate each of the functions based on the supplied FuncData objects
		std::list< FunctionDecl * > newFuncs;
		// structure that iterates aggregate decl members, returning their types
		auto generator = makeFuncGenerator( lazy_map( aggregateDecl->members, declToType ), refType, functionNesting, typeParams, back_inserter( newFuncs ) );
		for ( const FuncData & d : data ) {
			generator.gen( d, aggregateDecl->is_thread() || aggregateDecl->is_monitor() );
		}

		// field ctors are only generated if default constructor and copy constructor are both generated
		unsigned numCtors = std::count_if( newFuncs.begin(), newFuncs.end(), [](FunctionDecl * dcl) { return CodeGen::isConstructor( dcl->get_name() ); } );

		if ( functionNesting == 0 ) {
			// forward declare if top-level struct, so that
			// type is complete as soon as its body ends
			// Note: this is necessary if we want structs which contain
			// generic (otype) structs as members.
			for ( FunctionDecl * dcl : newFuncs ) {
				addForwardDecl( dcl, declsToAdd );
			}
		}

		for ( FunctionDecl * dcl : newFuncs ) {
			// generate appropriate calls to member ctor, assignment
			// destructor needs to do everything in reverse, so pass "forward" based on whether the function is a destructor
			if ( ! CodeGen::isDestructor( dcl->get_name() ) ) {
				makeStructFunctionBody( aggregateDecl->get_members().begin(), aggregateDecl->get_members().end(), dcl );
			} else {
				makeStructFunctionBody( aggregateDecl->get_members().rbegin(), aggregateDecl->get_members().rend(), dcl, false );
			}
			if ( CodeGen::isAssignment( dcl->get_name() ) ) {
				// assignment needs to return a value
				FunctionType * assignType = dcl->get_functionType();
				assert( assignType->get_parameters().size() == 2 );
				ObjectDecl * srcParam = strict_dynamic_cast< ObjectDecl * >( assignType->get_parameters().back() );
				dcl->get_statements()->get_kids().push_back( new ReturnStmt( noLabels, new VariableExpr( srcParam ) ) );
			}
			declsToAdd.push_back( dcl );
		}

		// create constructors which take each member type as a parameter.
		// for example, for struct A { int x, y; }; generate
		//   void ?{}(A *, int) and void ?{}(A *, int, int)
		// Field constructors are only generated if default and copy constructor
		// are generated, since they need access to both
		if ( numCtors == 2 ) {
			FunctionType * memCtorType = genDefaultType( refType );
			cloneAll( typeParams, memCtorType->get_forall() );
			for ( std::list<Declaration *>::iterator i = aggregateDecl->get_members().begin(); i != aggregateDecl->get_members().end(); ++i ) {
				DeclarationWithType * member = dynamic_cast<DeclarationWithType *>( *i );
				assert( member );
				if ( isUnnamedBitfield( dynamic_cast< ObjectDecl * > ( member ) ) ) {
					// don't make a function whose parameter is an unnamed bitfield
					continue;
				} else if ( member->get_name() == "" ) {
					// don't assign to anonymous members
					// xxx - this is a temporary fix. Anonymous members tie into
					// our inheritance model. I think the correct way to handle this is to
					// cast the structure to the type of the member and let the resolver
					// figure out whether it's valid/choose the correct unnamed member
					continue;
				}
				memCtorType->get_parameters().push_back( new ObjectDecl( member->get_name(), Type::StorageClasses(), LinkageSpec::Cforall, 0, member->get_type()->clone(), 0 ) );
				FunctionDecl * ctor = genFunc( "?{}", memCtorType->clone(), functionNesting );
				makeStructFieldCtorBody( aggregateDecl->get_members().begin(), aggregateDecl->get_members().end(), ctor );
				declsToAdd.push_back( ctor );
			}
			delete memCtorType;
		}
	}

	/// generate a single union assignment expression (using memcpy)
	template< typename OutputIterator >
	void makeUnionFieldsAssignment( ObjectDecl * srcParam, ObjectDecl * dstParam, OutputIterator out ) {
		UntypedExpr *copy = new UntypedExpr( new NameExpr( "__builtin_memcpy" ) );
		copy->get_args().push_back( new AddressExpr( new VariableExpr( dstParam ) ) );
		copy->get_args().push_back( new AddressExpr( new VariableExpr( srcParam ) ) );
		copy->get_args().push_back( new SizeofExpr( srcParam->get_type()->clone() ) );
		*out++ = new ExprStmt( noLabels, copy );
	}

	/// generates the body of a union assignment/copy constructor/field constructor
	void makeUnionAssignBody( FunctionDecl * funcDecl ) {
		FunctionType * ftype = funcDecl->get_functionType();
		assert( ftype->get_parameters().size() == 2 );
		ObjectDecl * dstParam = strict_dynamic_cast< ObjectDecl * >( ftype->get_parameters().front() );
		ObjectDecl * srcParam = strict_dynamic_cast< ObjectDecl * >( ftype->get_parameters().back() );

		makeUnionFieldsAssignment( srcParam, dstParam, back_inserter( funcDecl->get_statements()->get_kids() ) );
		if ( CodeGen::isAssignment( funcDecl->get_name() ) ) {
			// also generate return statement in assignment
			funcDecl->get_statements()->get_kids().push_back( new ReturnStmt( noLabels, new VariableExpr( srcParam ) ) );
		}
	}

	/// generates union constructors, destructors, and assignment operator
	void makeUnionFunctions( UnionDecl *aggregateDecl, UnionInstType *refType, unsigned int functionNesting, std::list< Declaration * > & declsToAdd ) {
		// Make function polymorphic in same parameters as generic union, if applicable
		const std::list< TypeDecl* > & typeParams = aggregateDecl->get_parameters(); // List of type variables to be placed on the generated functions

		// default ctor/dtor need only first parameter
		// void ?{}(T *); void ^?{}(T *);
		FunctionType *ctorType = genDefaultType( refType );
		FunctionType *dtorType = genDefaultType( refType );

		// copy ctor needs both parameters
		// void ?{}(T *, T);
		FunctionType *copyCtorType = genCopyType( refType );

		// assignment needs both and return value
		// T ?=?(T *, T);
		FunctionType *assignType = genAssignType( refType );

		cloneAll( typeParams, ctorType->get_forall() );
		cloneAll( typeParams, dtorType->get_forall() );
		cloneAll( typeParams, copyCtorType->get_forall() );
		cloneAll( typeParams, assignType->get_forall() );

		// add unused attribute to parameters of default constructor and destructor
		ctorType->get_parameters().front()->get_attributes().push_back( new Attribute( "unused" ) );
		dtorType->get_parameters().front()->get_attributes().push_back( new Attribute( "unused" ) );

		// Routines at global scope marked "static" to prevent multiple definitions is separate translation units
		// because each unit generates copies of the default routines for each aggregate.
		FunctionDecl *assignDecl = genFunc( "?=?", assignType, functionNesting );
		FunctionDecl *ctorDecl = genFunc( "?{}",  ctorType, functionNesting );
		FunctionDecl *copyCtorDecl = genFunc( "?{}", copyCtorType, functionNesting );
		FunctionDecl *dtorDecl = genFunc( "^?{}", dtorType, functionNesting );

		makeUnionAssignBody( assignDecl );

		// body of assignment and copy ctor is the same
		makeUnionAssignBody( copyCtorDecl );

		// create a constructor which takes the first member type as a parameter.
		// for example, for Union A { int x; double y; }; generate
		// void ?{}(A *, int)
		// This is to mimic C's behaviour which initializes the first member of the union.
		std::list<Declaration *> memCtors;
		for ( Declaration * member : aggregateDecl->get_members() ) {
			if ( DeclarationWithType * field = dynamic_cast< DeclarationWithType * >( member ) ) {
				ObjectDecl * srcParam = new ObjectDecl( "src", Type::StorageClasses(), LinkageSpec::Cforall, 0, field->get_type()->clone(), 0 );

				FunctionType * memCtorType = ctorType->clone();
				memCtorType->get_parameters().push_back( srcParam );
				FunctionDecl * ctor = genFunc( "?{}", memCtorType, functionNesting );

				makeUnionAssignBody( ctor );
				memCtors.push_back( ctor );
				// only generate a ctor for the first field
				break;
			}
		}

		declsToAdd.push_back( ctorDecl );
		declsToAdd.push_back( copyCtorDecl );
		declsToAdd.push_back( dtorDecl );
		declsToAdd.push_back( assignDecl ); // assignment should come last since it uses copy constructor in return
		declsToAdd.splice( declsToAdd.end(), memCtors );
	}

	AutogenerateRoutines::AutogenerateRoutines() {
		// the order here determines the order that these functions are generated.
		// assignment should come last since it uses copy constructor in return.
		data.emplace_back( "?{}", genDefaultType, constructable );
		data.emplace_back( "?{}", genCopyType, copyable );
		data.emplace_back( "^?{}", genDefaultType, destructable );
		data.emplace_back( "?=?", genAssignType, assignable );
	}

	void AutogenerateRoutines::previsit( EnumDecl * enumDecl ) {
		visit_children = false;
		if ( ! enumDecl->get_members().empty() ) {
			EnumInstType *enumInst = new EnumInstType( Type::Qualifiers(), enumDecl->get_name() );
			// enumInst->set_baseEnum( enumDecl );
			makeEnumFunctions( enumInst, functionNesting, declsToAddAfter );
		}
	}

	void AutogenerateRoutines::previsit( StructDecl * structDecl ) {
		visit_children = false;
		if ( structDecl->has_body() && structsDone.find( structDecl->name ) == structsDone.end() ) {
			StructInstType structInst( Type::Qualifiers(), structDecl->name );
			for ( TypeDecl * typeDecl : structDecl->parameters ) {
				// need to visit assertions so that they are added to the appropriate maps
				acceptAll( typeDecl->assertions, *visitor );
				structInst.parameters.push_back( new TypeExpr( new TypeInstType( Type::Qualifiers(), typeDecl->name, typeDecl ) ) );
			}
			structInst.set_baseStruct( structDecl );
			makeStructFunctions( structDecl, &structInst, functionNesting, declsToAddAfter, data );
			structsDone.insert( structDecl->name );
		} // if
	}

	void AutogenerateRoutines::previsit( UnionDecl * unionDecl ) {
		visit_children = false;
		if ( ! unionDecl->get_members().empty() ) {
			UnionInstType unionInst( Type::Qualifiers(), unionDecl->get_name() );
			unionInst.set_baseUnion( unionDecl );
			for ( TypeDecl * typeDecl : unionDecl->get_parameters() ) {
				unionInst.get_parameters().push_back( new TypeExpr( new TypeInstType( Type::Qualifiers(), typeDecl->get_name(), typeDecl ) ) );
			}
			makeUnionFunctions( unionDecl, &unionInst, functionNesting, declsToAddAfter );
		} // if
	}

	Type * declToTypeDeclBase( Declaration * decl ) {
		if ( TypeDecl * td = dynamic_cast< TypeDecl * >( decl ) ) {
			return td->base;
		}
		return nullptr;
	}

	// generate ctor/dtors/assign for typedecls, e.g., otype T = int *;
	void AutogenerateRoutines::previsit( TypeDecl * typeDecl ) {
		visit_children = false;
		if ( ! typeDecl->base ) return;

		// generate each of the functions based on the supplied FuncData objects
		std::list< FunctionDecl * > newFuncs;
		std::list< Declaration * > tds { typeDecl };
		std::list< TypeDecl * > typeParams;
		TypeInstType refType( Type::Qualifiers(), typeDecl->name, typeDecl );
		auto generator = makeFuncGenerator( lazy_map( tds, declToTypeDeclBase ), &refType, functionNesting, typeParams, back_inserter( newFuncs ) );
		for ( const FuncData & d : data ) {
			generator.gen( d, false );
		}

		if ( functionNesting == 0 ) {
			// forward declare if top-level struct, so that
			// type is complete as soon as its body ends
			// Note: this is necessary if we want structs which contain
			// generic (otype) structs as members.
			for ( FunctionDecl * dcl : newFuncs ) {
				addForwardDecl( dcl, declsToAddAfter );
			}
		}

		for ( FunctionDecl * dcl : newFuncs ) {
			FunctionType * ftype = dcl->type;
			assertf( ftype->parameters.size() == 1 || ftype->parameters.size() == 2, "Incorrect number of parameters in autogenerated typedecl function: %zd", ftype->parameters.size() );
			DeclarationWithType * dst = ftype->parameters.front();
			DeclarationWithType * src = ftype->parameters.size() == 2 ? ftype->parameters.back() : nullptr;
			// generate appropriate calls to member ctor, assignment
			// destructor needs to do everything in reverse, so pass "forward" based on whether the function is a destructor
			UntypedExpr * expr = new UntypedExpr( new NameExpr( dcl->name ) );
			expr->args.push_back( new CastExpr( new VariableExpr( dst ), new ReferenceType( Type::Qualifiers(), typeDecl->base->clone() ) ) );
			if ( src ) expr->args.push_back( new CastExpr( new VariableExpr( src ), typeDecl->base->clone() ) );
			dcl->statements->kids.push_back( new ExprStmt( noLabels, expr ) );
			if ( CodeGen::isAssignment( dcl->get_name() ) ) {
				// assignment needs to return a value
				FunctionType * assignType = dcl->type;
				assert( assignType->parameters.size() == 2 );
				ObjectDecl * srcParam = strict_dynamic_cast< ObjectDecl * >( assignType->parameters.back() );
				dcl->statements->kids.push_back( new ReturnStmt( noLabels, new VariableExpr( srcParam ) ) );
			}
			declsToAddAfter.push_back( dcl );
		}
	}

	void AutogenerateRoutines::previsit( FunctionType *) {
		// ensure that we don't add assignment ops for types defined as part of the function
		visit_children = false;
	}

	void AutogenerateRoutines::previsit( PointerType *) {
		// ensure that we don't add assignment ops for types defined as part of the pointer
		visit_children = false;
	}

	void AutogenerateRoutines::previsit( TraitDecl * ) {
		// ensure that we don't add assignment ops for types defined as part of the trait
		visit_children = false;
	}

	void AutogenerateRoutines::previsit( FunctionDecl * functionDecl ) {
		visit_children = false;
		// record the existence of this function as appropriate
		insert( functionDecl, constructable, InitTweak::isDefaultConstructor );
		insert( functionDecl, assignable, InitTweak::isAssignment );
		insert( functionDecl, copyable, InitTweak::isCopyConstructor );
		insert( functionDecl, destructable, InitTweak::isDestructor );

		maybeAccept( functionDecl->type, *visitor );
		functionNesting += 1;
		maybeAccept( functionDecl->statements, *visitor );
		functionNesting -= 1;
	}

	void AutogenerateRoutines::previsit( CompoundStmt * ) {
		GuardScope( constructable );
		GuardScope( assignable );
		GuardScope( copyable );
		GuardScope( destructable );
		GuardScope( structsDone );
	}

	void makeTupleFunctionBody( FunctionDecl * function ) {
		FunctionType * ftype = function->get_functionType();
		assertf( ftype->get_parameters().size() == 1 || ftype->get_parameters().size() == 2, "too many parameters in generated tuple function" );

		UntypedExpr * untyped = new UntypedExpr( new NameExpr( function->get_name() ) );

		/// xxx - &* is used to make this easier for later passes to handle
		untyped->get_args().push_back( new AddressExpr( UntypedExpr::createDeref( new VariableExpr( ftype->get_parameters().front() ) ) ) );
		if ( ftype->get_parameters().size() == 2 ) {
			untyped->get_args().push_back( new VariableExpr( ftype->get_parameters().back() ) );
		}
		function->get_statements()->get_kids().push_back( new ExprStmt( noLabels, untyped ) );
		function->get_statements()->get_kids().push_back( new ReturnStmt( noLabels, UntypedExpr::createDeref( new VariableExpr( ftype->get_parameters().front() ) ) ) );
	}

	void AutogenTupleRoutines::postvisit( TupleType * tupleType ) {
		std::string mangleName = SymTab::Mangler::mangleType( tupleType );
		if ( seenTuples.find( mangleName ) != seenTuples.end() ) return;
		seenTuples.insert( mangleName );

		// T ?=?(T *, T);
		FunctionType *assignType = genAssignType( tupleType );

		// void ?{}(T *); void ^?{}(T *);
		FunctionType *ctorType = genDefaultType( tupleType );
		FunctionType *dtorType = genDefaultType( tupleType );

		// void ?{}(T *, T);
		FunctionType *copyCtorType = genCopyType( tupleType );

		std::set< TypeDecl* > done;
		std::list< TypeDecl * > typeParams;
		for ( Type * t : *tupleType ) {
			if ( TypeInstType * ty = dynamic_cast< TypeInstType * >( t ) ) {
				if ( ! done.count( ty->get_baseType() ) ) {
					TypeDecl * newDecl = new TypeDecl( ty->get_baseType()->get_name(), Type::StorageClasses(), nullptr, TypeDecl::Any );
					TypeInstType * inst = new TypeInstType( Type::Qualifiers(), newDecl->get_name(), newDecl );
					newDecl->get_assertions().push_back( new FunctionDecl( "?=?", Type::StorageClasses(), LinkageSpec::Cforall, genAssignType( inst ), nullptr,
																		   std::list< Attribute * >(), Type::FuncSpecifiers( Type::Inline ) ) );
					newDecl->get_assertions().push_back( new FunctionDecl( "?{}", Type::StorageClasses(), LinkageSpec::Cforall, genDefaultType( inst ), nullptr,
																		   std::list< Attribute * >(), Type::FuncSpecifiers( Type::Inline ) ) );
					newDecl->get_assertions().push_back( new FunctionDecl( "?{}", Type::StorageClasses(), LinkageSpec::Cforall, genCopyType( inst ), nullptr,
																		   std::list< Attribute * >(), Type::FuncSpecifiers( Type::Inline ) ) );
					newDecl->get_assertions().push_back( new FunctionDecl( "^?{}", Type::StorageClasses(), LinkageSpec::Cforall, genDefaultType( inst ), nullptr,
																		   std::list< Attribute * >(), Type::FuncSpecifiers( Type::Inline ) ) );
					typeParams.push_back( newDecl );
					done.insert( ty->get_baseType() );
				}
			}
		}
		cloneAll( typeParams, ctorType->get_forall() );
		cloneAll( typeParams, dtorType->get_forall() );
		cloneAll( typeParams, copyCtorType->get_forall() );
		cloneAll( typeParams, assignType->get_forall() );

		FunctionDecl *assignDecl = genFunc( "?=?", assignType, functionNesting );
		FunctionDecl *ctorDecl = genFunc( "?{}", ctorType, functionNesting );
		FunctionDecl *copyCtorDecl = genFunc( "?{}", copyCtorType, functionNesting );
		FunctionDecl *dtorDecl = genFunc( "^?{}", dtorType, functionNesting );

		makeTupleFunctionBody( assignDecl );
		makeTupleFunctionBody( ctorDecl );
		makeTupleFunctionBody( copyCtorDecl );
		makeTupleFunctionBody( dtorDecl );

		declsToAddBefore.push_back( ctorDecl );
		declsToAddBefore.push_back( copyCtorDecl );
		declsToAddBefore.push_back( dtorDecl );
		declsToAddBefore.push_back( assignDecl ); // assignment should come last since it uses copy constructor in return
	}

	void AutogenTupleRoutines::previsit( FunctionDecl *functionDecl ) {
		visit_children = false;
		maybeAccept( functionDecl->type, *visitor );
		functionNesting += 1;
		maybeAccept( functionDecl->statements, *visitor );
		functionNesting -= 1;
	}

	void AutogenTupleRoutines::previsit( CompoundStmt * ) {
		GuardScope( seenTuples );
	}
} // SymTab

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