'' AST assignment nodes
'' l = destine; r = source
''
'' chng: sep/2004 written [v1ctor]

#include once "fb.bi"
#include once "fbint.bi"
#include once "ir.bi"
#include once "rtl.bi"
#include once "ast.bi"

private function hCheckStringOps _
	( _
		byval l as ASTNODE ptr, _
		byval ldclass as FB_DATACLASS, _
		byval r as ASTNODE ptr, _
		byval rdclass as FB_DATACLASS _
	) as integer

	dim as ASTNODE ptr other = any

	function = FALSE

	'' Other operand must be a z/wstring then
	'' (since they're not both strings)
	if( ldclass = FB_DATACLASS_STRING ) then
		other = r
	else
		other = l
	end if

	select case( astGetDataType( other ) )
	case FB_DATATYPE_CHAR, FB_DATATYPE_WCHAR

	case else
		exit function
	end select

	function = TRUE
end function

'':::::
private function hCheckUDTOps _
	( _
		byval l as ASTNODE ptr, _
		byval ldclass as FB_DATACLASS, _
		byref r as ASTNODE ptr, _
		byval rdclass as FB_DATACLASS, _
		byval checkOnly as integer = TRUE _ 
	) as integer

	dim as FBSYMBOL ptr proc = any

	function = FALSE

	'' l node must be an UDT's,
	if( astGetDataType( l ) <> FB_DATATYPE_STRUCT ) then
		exit function
	else
		'' "udtfunct() = udt" is not allowed, l node must be a variable
		if( l->class = AST_NODECLASS_CALL ) then
			exit function
		end if
	end if

    '' is r an UDT?
	if( astGetDataType( r ) <> FB_DATATYPE_STRUCT ) then
		exit function
	end if

   	'' different subtypes?
	if( l->subtype <> r->subtype ) then
		'' check if lhs is a base type of rhs
		if( symbGetUDTBaseLevel( r->subtype, l->subtype ) = 0 ) then
			exit function
		End If
		
		'' cast to the base type
		if( checkOnly = FALSE ) then
			r = astNewCONV( astGetDataType( l ), l->subtype, r )
		end if
	end if

	function = TRUE

end function

'':::::
private function hCheckWstringOps _
	( _
		byval l as ASTNODE ptr, _
		byref ldfull as integer, _
		byval r as ASTNODE ptr, _
		byref rdfull as integer, _
		byref is_zstr as integer _
	) as integer

	function = FALSE

	dim as integer ldtype = any, rdtype = any

	ldtype = typeGet( ldfull )
	rdtype = typeGet( rdfull )

    '' left?
	if( ldtype = FB_DATATYPE_WCHAR ) then
		'' is right a zstring? (fixed- or
		'' var-len strings won't reach here)
		is_zstr = (rdtype = FB_DATATYPE_CHAR)
	'' right?
	else
		'' is left a zstring?
		is_zstr = (ldtype = FB_DATATYPE_CHAR)
	end if

	if( is_zstr ) then
		return TRUE
	end if

	'' one is not a string, nor a udt, treat as
	'' numeric type, let emit convert them if needed..
	if( ldtype = FB_DATATYPE_WCHAR ) then
		'' don't allow, unless it's a pointer
		if( astIsDEREF( l ) = FALSE ) then
			exit function
		end if

		'' remap the type or the optimizer will
		'' assume it's a string assignment
		ldfull = typeJoin( ldfull, env.target.wchar )
	else
		'' same as above..
		if( astIsDEREF( r ) = FALSE ) then
			exit function
		end if

		rdfull = typeJoin( rdfull, env.target.wchar )
	end if

	function = TRUE
end function

private function hCheckZstringOps _
	( _
		byval l as ASTNODE ptr, _
		byref ldfull as integer, _
		byval r as ASTNODE ptr, _
		byref rdfull as integer _
	) as integer

	function = FALSE

	'' same as for wstring's..
	if( typeGet( ldfull ) = FB_DATATYPE_CHAR ) then
		'' don't allow, unless it's a pointer
		if( astIsDEREF( l ) = FALSE ) then
			exit function
		end if

		ldfull = typeJoin( ldfull, FB_DATATYPE_UBYTE )
	else
		'' same as above..
		if( astIsDEREF( r ) = FALSE ) then
			exit function
		end if

		rdfull = typeJoin( rdfull, FB_DATATYPE_UBYTE )
	end if

	function = TRUE
end function

'':::::
private sub hCheckEnumOps _
	( _
		byval l as ASTNODE ptr, _
		byval ldclass as FB_DATACLASS, _
		byval r as ASTNODE ptr, _
		byval rdclass as FB_DATACLASS _
	)

    '' not the same?
    if( astGetDataType( l ) <> astGetDataType( r ) ) then
    	if( (ldclass <> FB_DATACLASS_INTEGER) or _
    		(rdclass <> FB_DATACLASS_INTEGER) ) then
    		errReportWarn( FB_WARNINGMSG_IMPLICITCONVERSION )
    	end if
    end if

end sub

private function hCheckConstAndPointerOps _
	( _
		byval l as ASTNODE ptr, _
		byval ldtype as FB_DATATYPE, _
		byval r as ASTNODE ptr, _
		byval rdtype as FB_DATATYPE _
	) as integer

	function = FALSE

	'' lhs marked CONST? disallow the assignment then.
	if( symbCheckConstAssignTopLevel( ldtype, rdtype, l->subtype, r->subtype ) = FALSE ) then
		errReport( FB_ERRMSG_ILLEGALASSIGNMENT, TRUE )
		exit function
	end if

	if( typeIsPtr( ldtype ) ) then
		'' Disallow ptr = float
		if( typeGetClass( rdtype ) = FB_DATACLASS_FPOINT ) then
			exit function
		end if

		if( astPtrCheck( ldtype, l->subtype, FB_PARAMMODE_BYVAL, r ) = FALSE ) then
			'' if both are UDT, a derived lhs can't be assigned from a base rhs
			if( typeGetDtOnly( ldtype ) = FB_DATATYPE_STRUCT and typeGetDtOnly( rdtype ) = FB_DATATYPE_STRUCT ) then
				if( symbGetUDTBaseLevel( astGetSubType( l ), astGetSubType( r ) ) > 0 ) then
					errReport( FB_ERRMSG_ILLEGALASSIGNMENT, TRUE )
					exit function
				end if
			end if

			'' Only show the warning if the coming astNewCONV() will probably succeed
			if( astCheckCONV( l->dtype, l->subtype, r ) ) then
				errReportWarn( FB_WARNINGMSG_SUSPICIOUSPTRASSIGN )
			end if
		end if

	'' r-side expr is a ptr?
	elseif( typeIsPtr( rdtype ) ) then
		'' Disallow float = ptr
		if( typeGetClass( ldtype ) = FB_DATACLASS_FPOINT ) then
			exit function
		end if
		errReportWarn( FB_WARNINGMSG_IMPLICITCONVERSION )
	end if

	function = TRUE
end function

'':::::
function astCheckASSIGN _
	( _
		byval l as ASTNODE ptr, _
		byval r as ASTNODE ptr _
	) as integer

    dim as ASTNODE ptr n = any
    dim as FB_DATATYPE ldtype = any, rdtype = any, ldfull = any, rdfull = any
    dim as FB_DATACLASS ldclass = any, rdclass = any

	function = FALSE

	ldfull = astGetFullType( l )
	rdfull = astGetFullType( r )
	ldtype = typeGet( ldfull )
	rdtype = typeGet( rdfull )
	ldclass = typeGetClass( ldtype )
	rdclass = typeGetClass( rdtype )

    '' strings?
    if( (ldclass = FB_DATACLASS_STRING) or _
    	(rdclass = FB_DATACLASS_STRING) ) then

		'' both not strings?
		if( ldclass <> rdclass ) then
			if( hCheckStringOps( l, ldclass, r, rdclass ) = FALSE ) then
				exit function
			end if
		end if

		return TRUE

	'' UDT's?
	elseif( (ldtype = FB_DATATYPE_STRUCT) or _
			(rdtype = FB_DATATYPE_STRUCT) ) then

		if( hCheckUDTOps( l, ldclass, r, rdclass, TRUE ) = FALSE ) then
			exit function
		end if

		return TRUE

    '' wstrings?
    elseif( (ldtype = FB_DATATYPE_WCHAR) or _
    		(rdtype = FB_DATATYPE_WCHAR) ) then

		'' both = wstrings?
		if( ldtype <> rdtype ) then
    		dim as integer is_zstr
			if( hCheckWstringOps( l, ldfull, r, rdfull, is_zstr ) = FALSE ) then
				exit function
			end if

			if( is_zstr ) then
				return TRUE
			end if

			'' hCheckWstringOps() may have remapped the types
			ldclass = typeGetClass( ldfull )
			rdclass = typeGetClass( rdfull )
			ldtype = typeGet( ldfull )
			rdtype = typeGet( rdfull )
		end if

    '' zstrings?
    elseif( (ldtype = FB_DATATYPE_CHAR) or _
    		(rdtype = FB_DATATYPE_CHAR) ) then

		'' both zstrings?
		if( ldtype = rdtype ) then
			return TRUE
		end if

		if( hCheckZstringOps( l, ldfull, r, rdfull ) = FALSE ) then
			exit function
		end if

		'' hCheckZstringOps() may have remapped the types
		ldclass = typeGetClass( ldfull )
		rdclass = typeGetClass( rdfull )
		ldtype = typeGet( ldfull )
		rdtype = typeGet( rdfull )

    '' enums?
    elseif( (ldtype = FB_DATATYPE_ENUM) or _
    		(rdtype = FB_DATATYPE_ENUM) ) then
		hCheckEnumOps( l, ldclass, r, rdclass )
	end if

    '' check pointers
	if( hCheckConstAndPointerOps( l, ldfull, r, rdfull ) = FALSE ) then
		exit function
	end if

	'' convert types if needed
	if( (ldtype <> rdtype) or (l->subtype <> r->subtype) ) then
		'' don't convert strings
		if( rdclass <> FB_DATACLASS_STRING ) then
			'' constant?
			if( astIsCONST( r ) ) then
				r = astNewCONV( ldfull, l->subtype, r )
				if( r = NULL ) then
					exit function
				end if
			end if

			if( astCheckCONV( ldfull, l->subtype, r ) = FALSE ) then
				exit function
			end if
		end if
	end if

	function = TRUE
end function

function astCheckASSIGNToType _
	( _
		byval ldtype as integer, _
		byval lsubtype as FBSYMBOL ptr, _
		byval r as ASTNODE ptr _
	) as integer

	dim as ASTNODE ptr l = any

	l = astNewVAR( NULL, 0, ldtype, lsubtype )

	function = astCheckASSIGN( l, r )

	astDelTree( l )
end function

'' Check whether it's ok to assign
''   l = r
'' where l is a reference.
function astCheckByrefAssign _
	( _
		byval ldtype as integer, _
		byval lsubtype as FBSYMBOL ptr, _
		byval r as ASTNODE ptr _
	) as integer
	function = (typeCalcMatch( ldtype, lsubtype, FB_PARAMMODE_BYREF, r->dtype, r->subtype ) > FB_OVLPROC_NO_MATCH)
end function

private function hShallowCopy _
	( _
		byval l as ASTNODE ptr, _
		byval r as ASTNODE ptr, _
		byval options as integer _
	) as ASTNODE ptr

	dim as ASTNODE ptr t = any
	dim as longint offset = any, bytestocopy = any
	dim as integer has_vptr = any

	assert( astGetDataType( l ) = FB_DATATYPE_STRUCT )
	assert( astGetDataType( r ) = FB_DATATYPE_STRUCT )

	'' hCheckUDTOps() should have ensured this, but anyways:
	'' rhs must be >= lhs, i.e. either they must be the same UDT, or the
	'' rhs must be derived from the lhs.
	assert( (l->subtype = r->subtype) or (symbGetUDTBaseLevel( r->subtype, l->subtype ) > 0) )

	'' How much to copy must depend on the possibly-casted lhs, since that's
	'' what we're writing into, and we don't want a buffer overflow.
	bytestocopy = symbGetLen( l->subtype )
	has_vptr = symbGetHasRTTI( l->subtype )

	'' Need to remove casts before doing ADDROF or passing to astNewMEM().
	l = astRemoveNoConvCAST( l )
	r = astRemoveNoConvCAST( r )

	if( has_vptr ) then
		'' Don't overwrite the vptr when copying class UDTs without a
		'' Let overload, because the lhs object doesn't change its type
		'' or size, so its vptr must stay the same.
		''
		'' This also means that if this is a copy construction, we must
		'' initialize the lhs' vptr here. (normally it'd be done by a
		'' constructor call, but as long as we allow copy construction
		'' by shallow copy, we have to handle it here too). Luckily this
		'' never happens in practice because OBJECT has a copy
		'' constructor that is supposed to be used instead, and that
		'' should cause all derived types to have one too.
		assert( (options and AST_OPOPT_ISINI) = 0 )

		assert( bytestocopy >= env.pointersize )
		bytestocopy -= env.pointersize

		'' If it was just OBJECT, then there's nothing left to copy.
		if( bytestocopy = 0 ) then
			'' Nothing to do, so l/r can be deleted - unless they
			'' have side-effects; then we use astRemSideFx() and
			'' delete the side-effect-free reference it produced.
			t = NULL
			if( astHasSideFx( l ) ) then
				t = astNewLINK( t, astRemSideFx( l ) )
			end if
			if( astHasSideFx( r ) ) then
				t = astNewLINK( t, astRemSideFx( r ) )
			end if
			astDelTree( l )
			astDelTree( r )

			'' Can't just return NULL from astNewASSIGN() because
			'' that would be misinterpreted as an error.
			if( t = NULL ) then
				t = astNewNOP( )
			end if

			return t
		end if

		'' Skip the vptr on both sides.
		'' Casting to byte (could be another generic type aswell) for
		'' consistency, because after adding the offset, l/r no longer
		'' point to the original UDT.
		l = astBuildDerefAddrOf( l, env.pointersize, FB_DATATYPE_BYTE, NULL )
		r = astBuildDerefAddrOf( r, env.pointersize, FB_DATATYPE_BYTE, NULL )
	end if

	function = astNewMEM( AST_OP_MEMMOVE, l, r, bytestocopy )
end function

function astNewASSIGN _
	( _
		byval l as ASTNODE ptr, _
		byval r as ASTNODE ptr, _
		byval options as AST_OPOPT _
	) as ASTNODE ptr

	dim as ASTNODE ptr n = any, tr = any
    dim as FB_DATATYPE ldtype = any, rdtype = any, ldfull = any, rdfull = any
    dim as FB_DATACLASS ldclass = any, rdclass = any
    dim as FBSYMBOL ptr lsubtype = any, proc = any
	dim as FB_ERRMSG err_num = any
	dim as integer do_move = any

	function = NULL

	if( (l = NULL) or (r = NULL) ) then
		exit function
	end if

	ldfull = astGetFullType( l )
	ldtype = typeGet( ldfull )
	ldclass = typeGetClass( ldtype )
	lsubtype = l->subtype

	rdfull = astGetFullType( r )
	rdtype = typeGet( rdfull )
	rdclass = typeGetClass( rdtype )

	'' 1st) check assign op overloading (unless the types are the same and
	''      there's no clone function: just do a shallow copy)
	if( (options and AST_OPOPT_DONTCHKOPOVL) = 0 ) then

   		dim as integer check_letop = TRUE

   		select case as const ldtype
   		case FB_DATATYPE_STRUCT ', FB_DATATYPE_CLASS
			if( ldtype = rdtype ) then
				if( l->subtype = r->subtype ) then

					'' Only invoke the LET operator if it's not an
					'' initialization.  The initializer should be
					'' a fully constructed object.
					if( (options and AST_OPOPT_ISINI) = 0 ) then
						check_letop = symbCompHasCopyLetOps( l->subtype )
					else
						check_letop = FALSE
					end if
				end if
			end if
		end select

		if( check_letop ) then
			proc = symbFindSelfBopOvlProc( AST_OP_ASSIGN, l, r, @err_num )
			if( proc <> NULL ) then
				dim as ASTNODE ptr result = any

				'' if this is a variable initialization, we have to
				'' ensure that the variable is zeroed in memory,
				'' because operator let could do nothing.
				if( (options and AST_OPOPT_ISINI) <> 0 ) then
					if( symbGetCompDefCtor( l->subtype ) <> NULL ) then
	   					result = astBuildCtorCall( l->subtype, astCloneTree( l ) )
	   				else
						result = astNewMEM( AST_OP_MEMCLEAR, _
						                    astCloneTree( l ), _
						                    astNewCONSTi( symbGetLen( l->subtype ) ) )
					end if
				else
					result = NULL
				end if

				'' build a proc call
				return astNewLINK( result, astBuildCall( proc, l, r ) )
			end if

			if( err_num <> FB_ERRMSG_OK ) then
				return NULL
			end if
		end if
	end if

	'' 2nd) implicit casting op overloading
	if( (options and AST_OPOPT_DONTCHKOPOVL) = 0 ) then
		proc = symbFindCastOvlProc( ldfull, lsubtype, r, @err_num )
		if( proc <> NULL ) then

			'' we don't have to worry about initializing the lhs
			'' in case of an initialization, this is because in
			'' parser-decl-symb-init.bas::hDoAssign( ), the node
			'' has already been converted if necessary, therefore
			'' it would fall back on either a shallow copy, or the
			'' operator LET, which was handled just above.

			'' build a proc call
			r = astBuildCall( proc, r )
		else
			if( err_num <> FB_ERRMSG_OK ) then
				return NULL
			end if
		end if
	end if

	rdfull = astGetFullType( r )
	rdtype = typeGet( rdfull )
	rdclass = typeGetClass( rdtype )

    '' strings?
    if( (ldclass = FB_DATACLASS_STRING) or _
    	(rdclass = FB_DATACLASS_STRING) ) then

		'' both not strings?
		if( ldclass <> rdclass ) then
			if( hCheckStringOps( l, ldclass, r, rdclass ) = FALSE ) then
				exit function
			end if

			return rtlStrAssign( l, r, (options and AST_OPOPT_ISINI) <> 0 )
		end if

		'' otherwise, don't do any assignment by now to allow optimizations..
		if( (options and AST_OPOPT_ISINI) <> 0 ) then
			'' unless it's an initialization
			return rtlStrAssign( l, r, TRUE	)
		end if

	'' UDT's?
	elseif( (ldtype = FB_DATATYPE_STRUCT) or _
			(rdtype = FB_DATATYPE_STRUCT) ) then

		if( hCheckUDTOps( l, ldclass, r, rdclass, FALSE ) = FALSE ) then
			exit function
		end if

		'' No Let overload found above; so do a shallow copy

		'' type ini tree?
		if( astIsTYPEINI( r ) ) then
			'' Initialize the lhs with the TYPEINI directly,
			'' instead of using a temp var and then copying that,
			'' unless there are ctors/dtors (let/cast overloads were
			'' already handled above).
			if( (typeHasCtor( l->dtype, l->subtype ) or typeHasDtor( l->dtype, l->subtype )) = FALSE ) then
				return astTypeIniFlush( astRemoveNoConvCAST( l ), r, TRUE, options and AST_OPOPT_ISINI )
			end if
		end if

		tr = astSkipNoConvCAST( r )

		if( astIsCALL( tr ) = FALSE ) then
			'' Not a CALL, it must be an UDT in memory, copy from that
			return hShallowCopy( l, r, options )
		end if

		if( symbProcReturnsOnStack( tr->sym ) ) then
			'' Returning on stack, copy from the temp result var
			return hShallowCopy( l, astBuildCallResultVar( astRemoveNoConvCAST( r ) ), options )
		end if

		'' Returning in registers, patch the types to integer and then
		'' do a normal integer ASSIGN. (can't do a shallow copy from
		'' memory because the UDT is in registers... would have to copy
		'' to a temp var first)
		l = astRemoveNoConvCAST( l )
		r = astRemoveNoConvCAST( r )
		assert( astIsCALL( r ) )
		assert( symbIsRef( r->sym ) = FALSE )

		ldfull = symbGetProcRealType( r->sym )
		ldtype = typeGet( ldfull )
		lsubtype = symbGetProcRealSubtype( r->sym )
		ldclass = typeGetClass( ldtype )
		astSetType( l, ldfull, lsubtype )

		rdfull = ldfull
		rdtype = ldtype
		rdclass = ldclass
		astSetType( r, rdfull, lsubtype )

    '' wstrings?
    elseif( (ldtype = FB_DATATYPE_WCHAR) or _
    		(rdtype = FB_DATATYPE_WCHAR) ) then

		'' If both are wstrings, delay assignment until astOptimizeTree(),
		'' unless it's an initialization, then we can't do optimizations anyways.
		'' (see also STRING handling above)
		if( ldtype = rdtype ) then
			if( (options and AST_OPOPT_ISINI) <> 0 ) then
				return rtlWstrAssign( l, r, TRUE )
			end if
		else
			dim as integer is_zstr
			if( hCheckWstringOps( l, ldfull, r, rdfull, is_zstr ) = FALSE ) then
				exit function
			end if

			'' one of them is an ascii string, just assign
			if( is_zstr ) then
				return rtlWstrAssign( l, r, (options and AST_OPOPT_ISINI) <> 0 )
			end if

			'' hCheckWstringOps() may have remapped the types
			ldclass = typeGetClass( ldfull )
			rdclass = typeGetClass( rdfull )
			ldtype = typeGet( ldfull )
			rdtype = typeGet( rdfull )
		end if

    '' zstrings?
    elseif( (ldtype = FB_DATATYPE_CHAR) or _
    		(rdtype = FB_DATATYPE_CHAR) ) then

		'' both the same? assign as string..
		if( ldtype = rdtype ) then
			return rtlStrAssign( l, r )
		end if

		if( hCheckZstringOps( l, ldfull, r, rdfull ) = FALSE ) then
			exit function
		end if

		'' hCheckZstringOps() may have remapped the types
		ldclass = typeGetClass( ldfull )
		rdclass = typeGetClass( rdfull )
		ldtype = typeGet( ldfull )
		rdtype = typeGet( rdfull )

    '' enums?
    elseif( (ldtype = FB_DATATYPE_ENUM) or _
    		(rdtype = FB_DATATYPE_ENUM) ) then
		hCheckEnumOps( l, ldclass, r, rdclass )
	end if

    '' check pointers
    if( (options and AST_OPOPT_DONTCHKPTR) = 0 ) then
		if( hCheckConstAndPointerOps( l, ldfull, r, rdfull ) = FALSE ) then
			exit function
		end if
    end if

	'' convert types if needed
	if( (ldtype <> rdtype) or (l->subtype <> r->subtype) ) then
		'' don't convert strings
		if( rdclass <> FB_DATACLASS_STRING ) then
			'' constant?
			if( astIsCONST( r ) ) then
				r = astNewCONV( ldfull, lsubtype, r, _
					iif( options and AST_OPOPT_DONTCHKPTR, AST_CONVOPT_DONTCHKPTR, 0 ) )
				if( r = NULL ) then
					exit function
				end if
			end if

			'' let the fpu do the conversion if any operand
			'' is a float (unless a special case must be handled)
			dim as integer doconv = TRUE
			if( env.clopt.backend = FB_BACKEND_GAS ) then
				if( (ldclass = FB_DATACLASS_FPOINT) or (rdclass = FB_DATACLASS_FPOINT) ) then
					if( ldtype <> FB_DATATYPE_ULONGINT ) then
						doconv = irGetOption( IR_OPT_FPUCONV )
					end if
				end if
			end if

			if( doconv ) then
				r = astNewCONV( ldfull, l->subtype, r, _
					iif( options and AST_OPOPT_DONTCHKPTR, AST_CONVOPT_DONTCHKPTR, 0 ) )
				if( r = NULL ) then
					exit function
				end if
			end if
		end if
	end if

	'' alloc new node
	n = astNewNode( AST_NODECLASS_ASSIGN, ldfull, lsubtype )

	n->l = l
	n->r = r

	function = n

end function

function astLoadASSIGN( byval n as ASTNODE ptr ) as IRVREG ptr
    dim as ASTNODE ptr l = any, r = any
    dim as IRVREG ptr vs = any, vr = any

	l = n->l
	r = n->r
	if( (l = NULL) or (r = NULL) ) then
		return NULL
	end if

	if( r->class = AST_NODECLASS_CONV ) then
		astUpdateCONVFD2FS( r, l->dtype, FALSE )
	end if

	vs = astLoad( r )
	vr = astLoad( l )

	if( ast.doemit ) then
		irEmitSTORE( vr, vs )
	end if

	astDelNode( l )
	astDelNode( r )

	function = vr
end function
