fcfield.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 153 行

/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
*    Public License version 1.0 (the 'License'). You may not use this file
*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
*    ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
*    provided with the Original Code and Modifications, and is also
*    available at www.sybase.com/developer/opensource.
*
*    The Original Code and all software distributed under the License are
*    distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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*  ========================================================================
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
*               DESCRIBE IT HERE!
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****************************************************************************/


//
// FCFIELD  : field selection operator
//

#include "ftnstd.h"
#include "symbol.h"
#include "wf77defs.h"
#include "cg.h"
#include "emitobj.h"
#include "fctypes.h"

//=================== Back End Code Generation Routines ====================

extern  cg_name         CGBinary(cg_op,cg_name,cg_name,cg_type);
extern  cg_name         CGInteger(signed_32,cg_type);
extern  cg_name         CGVolatile(cg_name);

//=========================================================================

extern  void            XPush(cg_name);
extern  cg_name         XPopValue(cg_type);
extern  cg_name         XPop(void);
extern  cg_name         ConstArrayOffset(act_dim_list *);
extern  void            CloneCGName(cg_name,cg_name *,cg_name *);
extern  cg_type         SymPtrType(sym_id);


void            FCFieldOp( void ) {
//===========================

// Perform field selection.

    sym_id      sym;
    cg_name     base;
    cg_type     ptr_type;
    cg_name     addr;

    sym = GetPtr();
    base = XPop();
    if( ( sym->ns.flags & SY_CLASS ) == SY_SUBPROGRAM ) {
        // function returning a structure
        ptr_type = T_LOCAL_POINTER;
    } else {
        ptr_type = SymPtrType( sym );
    }
    // add offset of field
    addr = CGBinary( O_PLUS, base, XPopValue( T_INT_4 ), ptr_type );
    if( sym->ns.xflags & SY_VOLATILE ) {
        addr = CGVolatile( addr );
    }
    XPush( addr );
}


cg_name FieldArrayEltSize( sym_id fd ) {
//======================================

// Return size of an array element.  Array is a field in a structure.

    if( fd->fd.typ == TY_STRUCTURE ) {
        return( CGInteger( fd->fd.xt.record->size, T_INTEGER ) );
    } else {
        return( CGInteger( fd->fd.xt.size, T_INTEGER ) );
    }
}


void    FCFieldSubscript( void ) {
//==========================

    sym_id      fd;
    cg_name     size;
    cg_name     base;

    fd = GetPtr();
    base = XPop();
    size = FieldArrayEltSize( fd );
    XPush( CGBinary( O_PLUS, base,
                     CGBinary( O_TIMES, ConstArrayOffset( fd->fd.dim_ext ),
                               size, T_INTEGER ),
                     T_INT_4 ) );
}


void    FCFieldSubstring( void ) {
//==========================

    cg_name     base;
    cg_name     start_1;
    cg_name     start_2;
    cg_name     end;
    unsigned_16 typ_info;
    int         len;
    sym_id      fd;

    base = XPop();
    fd = GetPtr();   // skip the field name
    len = GetInt();
    typ_info = GetU16();
    start_1 =  XPopValue( GetType1( typ_info ) );
    if( len == 0 ) {
        CloneCGName( start_1, &start_1, &start_2 );
        end = XPop();
        if( end == NULL ) {
            end = CGInteger( fd->fd.xt.size, T_INTEGER );
        } else {
            XPush( end );
            end = XPopValue( GetType2( typ_info ) );
        }
        XPush( CGBinary( O_PLUS, CGInteger( 1, T_INTEGER ),
                         CGBinary( O_MINUS, end, start_2, T_INTEGER ),
                         T_INTEGER ) );
    } else {
        XPush( CGInteger( len, T_INTEGER ) );
    }
    XPush( CGBinary( O_PLUS, base,
                     CGBinary( O_MINUS, start_1, CGInteger( 1, T_INTEGER ),
                               T_INTEGER ),
                     T_INTEGER ) );
}