//
// 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.
//
// ResolveTypeof.cc --
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 12:12:20 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Tue May 19 16:49:04 2015
// Update Count     : 3
//

#include "ResolveTypeof.h"
#include "RenameVars.h"

#include <cassert>               // for assert

#include "AST/CVQualifiers.hpp"
#include "AST/Node.hpp"
#include "AST/Pass.hpp"
#include "AST/Type.hpp"
#include "AST/TypeEnvironment.hpp"
#include "Common/PassVisitor.h"  // for PassVisitor
#include "Common/utility.h"      // for copy
#include "Resolver.h"            // for resolveInVoidContext
#include "SynTree/Expression.h"  // for Expression
#include "SynTree/Mutator.h"     // for Mutator
#include "SynTree/Type.h"        // for TypeofType, Type
#include "SymTab/Mangler.h"
#include "InitTweak/InitTweak.h" // for isConstExpr

namespace SymTab {
class Indexer;
}  // namespace SymTab

namespace ResolvExpr {
	namespace {
#if 0
		void
		printAlts( const AltList &list, std::ostream &os, int indent = 0 )
		{
			for ( AltList::const_iterator i = list.begin(); i != list.end(); ++i ) {
				i->print( os, indent );
				os << std::endl;
			}
		}
#endif
	}

	class ResolveTypeof_old : public WithShortCircuiting {
	  public:
		ResolveTypeof_old( const SymTab::Indexer &indexer ) : indexer( indexer ) {}
		void premutate( TypeofType *typeofType );
		Type * postmutate( TypeofType *typeofType );

	  private:
		const SymTab::Indexer &indexer;
	};

	Type * resolveTypeof( Type *type, const SymTab::Indexer &indexer ) {
		PassVisitor<ResolveTypeof_old> mutator( indexer );
		return type->acceptMutator( mutator );
	}

	void ResolveTypeof_old::premutate( TypeofType * ) {
		visit_children = false;
	}

	Type * ResolveTypeof_old::postmutate( TypeofType *typeofType ) {
#if 0
		std::cerr << "resolving typeof: ";
		typeofType->print( std::cerr );
		std::cerr << std::endl;
#endif
		// pass on null expression
		if ( ! typeofType->expr ) return typeofType;

		bool isBasetypeof = typeofType->is_basetypeof;
		auto oldQuals = typeofType->get_qualifiers().val;

		Type* newType;
		if ( TypeExpr* tyExpr = dynamic_cast<TypeExpr*>(typeofType->expr) ) {
			// typeof wrapping type
			newType = tyExpr->type;
			tyExpr->type = nullptr;
			delete tyExpr;
		} else {
			// typeof wrapping expression
			Expression * newExpr = resolveInVoidContext( typeofType->expr, indexer );
			assert( newExpr->result && ! newExpr->result->isVoid() );
			newType = newExpr->result;
			newExpr->result = nullptr;
			delete typeofType;
			delete newExpr;
		}

		// clear qualifiers for base, combine with typeoftype quals in any case
		if ( isBasetypeof ) {
			// replace basetypeof(<enum>) by int
			if ( dynamic_cast<EnumInstType*>(newType) ) {
				Type* newerType =
					new BasicType{ newType->get_qualifiers(), BasicType::SignedInt,
					newType->attributes };
				delete newType;
				newType = newerType;
			}
			newType->get_qualifiers().val
				= ( newType->get_qualifiers().val & ~Type::Qualifiers::Mask ) | oldQuals;
		} else {
			newType->get_qualifiers().val |= oldQuals;
		}

		return newType;
	}

namespace {
	struct ResolveTypeof_new : public ast::WithShortCircuiting {
		const ast::SymbolTable & localSymtab;

		ResolveTypeof_new( const ast::SymbolTable & syms ) : localSymtab( syms ) {}

		void previsit( const ast::TypeofType * ) { visit_children = false; }

		const ast::Type * postvisit( const ast::TypeofType * typeofType ) {
			// pass on null expression
			if ( ! typeofType->expr ) return typeofType;

			ast::ptr< ast::Type > newType;
			if ( auto tyExpr = typeofType->expr.as< ast::TypeExpr >() ) {
				// typeof wrapping type
				newType = tyExpr->type;
			} else {
				// typeof wrapping expression
				ast::TypeEnvironment dummy;
				ast::ptr< ast::Expr > newExpr =
					resolveInVoidContext( typeofType->expr, localSymtab, dummy );
				assert( newExpr->result && ! newExpr->result->isVoid() );
				newType = newExpr->result;
			}

			// clear qualifiers for base, combine with typeoftype quals regardless
			if ( typeofType->kind == ast::TypeofType::Basetypeof ) {
				// replace basetypeof(<enum>) by int
				if ( newType.as< ast::EnumInstType >() ) {
					newType = new ast::BasicType{
						ast::BasicType::SignedInt, newType->qualifiers, copy(newType->attributes) };
				}
				reset_qualifiers(
					newType,
					( newType->qualifiers & ~ast::CV::EquivQualifiers ) | typeofType->qualifiers );
			} else {
				add_qualifiers( newType, typeofType->qualifiers );
			}

			return newType.release();
		}
	};
} // anonymous namespace

const ast::Type * resolveTypeof( const ast::Type * type , const ast::SymbolTable & symtab ) {
	ast::Pass< ResolveTypeof_new > mutator{ symtab };
	return type->accept( mutator );
}

struct FixArrayDimension {
	// should not require a mutable symbol table - prevent pass template instantiation
	const ast::SymbolTable & _symtab; 
	FixArrayDimension(const ast::SymbolTable & symtab): _symtab(symtab) {}

	const ast::ArrayType * previsit (const ast::ArrayType * arrayType) {
		if (!arrayType->dimension) return arrayType;
		auto mutType = mutate(arrayType);
		ast::ptr<ast::Type> sizetype = ast::sizeType ? ast::sizeType : new ast::BasicType(ast::BasicType::LongUnsignedInt); 
		mutType->dimension = findSingleExpression(arrayType->dimension, sizetype, _symtab);

		if (InitTweak::isConstExpr(mutType->dimension)) {
			mutType->isVarLen = ast::LengthFlag::FixedLen;
		}
		else {
			mutType->isVarLen = ast::LengthFlag::VariableLen;
		}
		return mutType;
	}
};

const ast::Type * fixArrayType( const ast::Type * type, const ast::SymbolTable & symtab) {
	ast::Pass<FixArrayDimension> visitor {symtab};
	return type->accept(visitor);
}

const ast::ObjectDecl * fixObjectType( const ast::ObjectDecl * decl , const ast::SymbolTable & symtab ) {
	if (!decl->isTypeFixed) { 
		auto mutDecl = mutate(decl);
		auto resolvedType = resolveTypeof(decl->type, symtab);
		resolvedType = fixArrayType(resolvedType, symtab);
		mutDecl->type = resolvedType;

		// check variable length if object is an array.
		// xxx - should this be part of fixObjectType?

		/*
		if (auto arrayType = dynamic_cast<const ast::ArrayType *>(resolvedType)) {
			auto dimExpr = findSingleExpression(arrayType->dimension, ast::sizeType, symtab);
			if (auto varexpr = arrayType->dimension.as<ast::VariableExpr>()) {// hoisted previously
				if (InitTweak::isConstExpr(varexpr->var.strict_as<ast::ObjectDecl>()->init)) {
					auto mutType = mutate(arrayType);
					mutType->isVarLen = ast::LengthFlag::VariableLen;
					mutDecl->type = mutType;
				}
			}
		}
		*/


		if (!mutDecl->name.empty()) 
			mutDecl->mangleName = Mangle::mangle(mutDecl); // do not mangle unnamed variables
		
		mutDecl->type = renameTyVars(mutDecl->type, RenameMode::GEN_EXPR_ID);
		mutDecl->isTypeFixed = true;
		return mutDecl;
	}
	return decl;
}

} // namespace ResolvExpr

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