//
// 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.
//
// Expr.cpp --
//
// Author           : Aaron B. Moss
// Created On       : Wed May 15 17:00:00 2019
// Last Modified By : Aaron B. Moss
// Created On       : Wed May 15 17:00:00 2019
// Update Count     : 1
//

#include "Expr.hpp"

#include <cassert>                 // for strict_dynamic_cast
#include <string>                  // for to_string
#include <vector>

#include "Type.hpp"
#include "Common/SemanticError.h"
#include "GenPoly/Lvalue.h"        // for referencesPermissable
#include "InitTweak/InitTweak.h"   // for getPointerBase
#include "ResolvExpr/typeops.h"    // for extractResultType

namespace ast {

// --- ApplicationExpr

ApplicationExpr::ApplicationExpr( const CodeLocation & loc, const Expr * f, 
	std::vector<ptr<Expr>> && as ) 
: Expr( loc ), func( f ), args( std::move(args) ) {
	// ensure that `ApplicationExpr` result type is `FuncExpr`
	const PointerType * pt = strict_dynamic_cast< const PointerType * >( f->result.get() );
	const FunctionType * fn = strict_dynamic_cast< const FunctionType * >( pt->base.get() );

	result = ResolvExpr::extractResultType( fn );
	assert( result );
}

// --- UntypedExpr

UntypedExpr * UntypedExpr::createDeref( const CodeLocation & loc, Expr * arg ) {
	assert( arg );

	UntypedExpr * ret = new UntypedExpr{ 
		loc, new NameExpr{loc, "*?"}, std::vector<ptr<Expr>>{ ptr<Expr>{ arg } } 
	};
	if ( const Type * ty = arg->result ) {
		const Type * base = InitTweak::getPointerBase( ty );
		assertf( base, "expected pointer type in dereference (type was %s)", toString( ty ).c_str() );

		if ( GenPoly::referencesPermissable() ) {
			// if references are still allowed in the AST, dereference returns a reference
			ret->result = new ReferenceType{ base };
		} else {
			// references have been removed, in which case dereference returns an lvalue of the 
			// base type
			ret->result.set_and_mutate( base )->set_lvalue( true );
		}
	}
	return ret;
}

UntypedExpr * UntypedExpr::createAssign( const CodeLocation & loc, Expr * lhs, Expr * rhs ) {
	assert( lhs && rhs );

	UntypedExpr * ret = new UntypedExpr{
		loc, new NameExpr{loc, "?=?"}, std::vector<ptr<Expr>>{ ptr<Expr>{ lhs }, ptr<Expr>{ rhs } }
	};
	if ( lhs->result && rhs->result ) {
		// if both expressions are typed, assumes that this assignment is a C bitwise assignment,
		// so the result is the type of the RHS
		ret->result = rhs->result;
	}
	return ret;
}

// --- AddressExpr

// Address expressions are typed based on the following inference rules:
//    E : lvalue T  &..& (n references)
//   &E :        T *&..& (n references)
//
//    E : T  &..&        (m references)
//   &E : T *&..&        (m-1 references)

namespace {
	/// The type of the address of a type.
	/// Caller is responsible for managing returned memory
	Type * addrType( const Type * type ) {
		if ( const ReferenceType * refType = dynamic_cast< const ReferenceType * >( type ) ) {
			CV::Qualifiers quals = refType->qualifiers;
			return new ReferenceType{ addrType( refType->base ), refType->qualifiers };
		} else {
			return new PointerType{ type };
		}
	}
}

AddressExpr::AddressExpr( const CodeLocation & loc, const Expr * a ) : Expr( loc ), arg( a ) {
	if ( arg->result ) {
		if ( arg->result->is_lvalue() ) {
			// lvalue, retains all levels of reference, and gains a pointer inside the references
			Type * res = addrType( arg->result );
			res->set_lvalue( false ); // result of & is never an lvalue
			result = res;
		} else {
			// taking address of non-lvalue, must be a reference, loses one layer of reference
			if ( const ReferenceType * refType = 
					dynamic_cast< const ReferenceType * >( arg->result.get() ) ) {
				Type * res = addrType( refType->base );
				res->set_lvalue( false ); // result of & is never an lvalue
				result = res;
			} else {
				SemanticError( loc, arg->result, 
					"Attempt to take address of non-lvalue expression: " );
			}
		}
	}
}

// --- LabelAddressExpr

// label address always has type `void*`
LabelAddressExpr::LabelAddressExpr( const CodeLocation & loc, Label && a ) 
: Expr( loc, new PointerType{ new VoidType{} } ), arg( a ) {}

// --- CastExpr

CastExpr::CastExpr( const CodeLocation & loc, const Expr * a, GeneratedFlag g ) 
: Expr( loc, new VoidType{} ), arg( a ), isGenerated( g ) {}

// --- KeywordCastExpr

const std::string & KeywordCastExpr::targetString() const {
	static const std::string targetStrs[] = {
		"coroutine", "thread", "monitor"
	};
	static_assert(
		(sizeof(targetStrs) / sizeof(targetStrs[0])) == ((unsigned long)NUMBER_OF_TARGETS),
		"Each KeywordCastExpr::Target should have a corresponding string representation"
	);
	return targetStrs[(unsigned long)target];
}

// --- MemberExpr

MemberExpr::MemberExpr( const CodeLocation & loc, const DeclWithType * mem, const Expr * agg )
: Expr( loc ), member( mem ), aggregate( agg ) {
	assert( member );
	assert( aggregate );
	assert( aggregate->result );

	assert(!"unimplemented; need TypeSubstitution, genericSubstitution");
}

// --- VariableExpr

VariableExpr::VariableExpr( const CodeLocation & loc, const DeclWithType * v )
: Expr( loc ), var( v ) {
	assert( var );
	assert( var->get_type() );
	result.set_and_mutate( var->get_type() )->set_lvalue( true );
}

VariableExpr * VariableExpr::functionPointer( 
		const CodeLocation & loc, const FunctionDecl * decl ) {
	// wrap usually-determined result type in a pointer
	VariableExpr * funcExpr = new VariableExpr{ loc, decl };
	funcExpr->result = new PointerType{ funcExpr->result };
	return funcExpr;
}

// --- ConstantExpr

long long int ConstantExpr::intValue() const {
	if ( const BasicType * bty = result.as< BasicType >() ) {
		if ( bty->isInteger() ) {
			return val.ival;
		}
	} else if ( result.as< ZeroType >() ) {
		return 0;
	} else if ( result.as< OneType >() ) {
		return 1;
	}
	SemanticError( this, "Constant expression of non-integral type " );
}

double ConstantExpr::floatValue() const {
	if ( const BasicType * bty = result.as< BasicType >() ) {
		if ( ! bty->isInteger() ) {
			return val.dval;
		}
	}
	SemanticError( this, "Constant expression of non-floating-point type " );
}

ConstantExpr * ConstantExpr::from_bool( const CodeLocation & loc, bool b ) {
	return new ConstantExpr{ 
		loc, new BasicType{ BasicType::Bool }, b ? "1" : "0", (unsigned long long)b };
}

ConstantExpr * ConstantExpr::from_char( const CodeLocation & loc, char c ) {
	return new ConstantExpr{ 
		loc, new BasicType{ BasicType::Char }, std::to_string( c ), (unsigned long long)c };
}

ConstantExpr * ConstantExpr::from_int( const CodeLocation & loc, int i ) {
	return new ConstantExpr{ 
		loc, new BasicType{ BasicType::SignedInt }, std::to_string( i ), (unsigned long long)i };
}

ConstantExpr * ConstantExpr::from_ulong( const CodeLocation & loc, unsigned long i ) {
	return new ConstantExpr{ 
		loc, new BasicType{ BasicType::LongUnsignedInt }, std::to_string( i ), 
		(unsigned long long)i };
}

ConstantExpr * ConstantExpr::from_double( const CodeLocation & loc, double d ) {
	return new ConstantExpr{ loc, new BasicType{ BasicType::Double }, std::to_string( d ), d };
}

ConstantExpr * ConstantExpr::from_string( const CodeLocation & loc, const std::string & s ) {
	return new ConstantExpr{
		loc,
		new ArrayType{ 
			new BasicType{ BasicType::Char, CV::Const },
			ConstantExpr::from_int( loc, s.size() + 1 /* null terminator */ ),
			FixedLen, DynamicDim },
		std::string{"\""} + s + "\"",
		(unsigned long long)0 };
}

ConstantExpr * ConstantExpr::null( const CodeLocation & loc, const Type * ptrType ) {
	return new ConstantExpr{
		loc, ptrType ? ptrType : new PointerType{ new VoidType{} }, "0", (unsigned long long)0 };
}

// --- SizeofExpr

SizeofExpr::SizeofExpr( const CodeLocation & loc, const Expr * e )
: Expr( loc, new BasicType{ BasicType::LongUnsignedInt } ), expr( e ), type( nullptr ) {}

SizeofExpr::SizeofExpr( const CodeLocation & loc, const Type * t )
: Expr( loc, new BasicType{ BasicType::LongUnsignedInt } ), expr( nullptr ), type( t ) {}

// --- AlignofExpr

AlignofExpr::AlignofExpr( const CodeLocation & loc, const Expr * e )
: Expr( loc, new BasicType{ BasicType::LongUnsignedInt } ), expr( e ), type( nullptr ) {}

AlignofExpr::AlignofExpr( const CodeLocation & loc, const Type * t )
: Expr( loc, new BasicType{ BasicType::LongUnsignedInt } ), expr( nullptr ), type( t ) {}

// --- UntypedOffsetofExpr

UntypedOffsetofExpr::UntypedOffsetofExpr( 
	const CodeLocation & loc, const Type * ty, const std::string & mem )
: Expr( loc, new BasicType{ BasicType::LongUnsignedInt } ), type( ty ), member( mem ) {
	assert( type );
}

// --- OffsetofExpr

OffsetofExpr::OffsetofExpr( const CodeLocation & loc, const Type * ty, const DeclWithType * mem )
: Expr( loc, new BasicType{ BasicType::LongUnsignedInt } ), type( ty ), member( mem ) {
	assert( type );
	assert( member );
}

// --- OffsetPackExpr

OffsetPackExpr::OffsetPackExpr( const CodeLocation & loc, const StructInstType * ty )
: Expr( loc, new ArrayType{ 
	new BasicType{ BasicType::LongUnsignedInt }, nullptr, FixedLen, DynamicDim } 
), type( ty ) {
	assert( type );
}

// --- LogicalExpr

LogicalExpr::LogicalExpr( 
	const CodeLocation & loc, const Expr * a1, const Expr * a2, LogicalFlag ia )
: Expr( loc, new BasicType{ BasicType::SignedInt } ), arg1( a1 ), arg2( a2 ), isAnd( ia ) {}

}

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