summaryrefslogtreecommitdiff
path: root/gnu/usr.bin/awk/fcall.c
blob: d8aee53d6964f9bc7727500a204049efad16e554 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365

/********************************************
fcall.c
copyright 1991, Michael D. Brennan

This is a source file for mawk, an implementation of
the AWK programming language.

Mawk is distributed without warranty under the terms of
the GNU General Public License, version 2, 1991.
********************************************/


/*$Log: fcall.c,v $
/*Revision 1.2  1993/07/02 23:57:16  jtc
/*Updated to mawk 1.1.4
/*
 * Revision 5.1  1991/12/05  07:55:54  brennan
 * 1.1 pre-release
 *
*/

#include "mawk.h"
#include "symtype.h"
#include "code.h"

/* This file has functions involved with type checking of
   function calls
*/

static  FCALL_REC *PROTO(first_pass, (FCALL_REC *) ) ;
static  CA_REC    *PROTO(call_arg_check, (FBLOCK *, CA_REC *,
        INST *, unsigned) ) ;
static  int PROTO(arg_cnt_ok, (FBLOCK *,CA_REC *, unsigned) ) ;


static int check_progress ;
    /* flag that indicates call_arg_check() was able to type
       check some call arguments */

/* type checks a list of call arguments,
   returns a list of arguments whose type is still unknown
*/
static CA_REC *call_arg_check( callee, entry_list , start,  line_no)
  FBLOCK *callee ;
  CA_REC *entry_list  ;  
  INST  *start ; /* to locate patch */
  unsigned line_no ; /* for error messages */
{ register CA_REC *q ;
  CA_REC *exit_list  = (CA_REC *) 0 ;

  check_progress = 0 ;

  /* loop :
       take q off entry_list
       test it
           if OK  zfree(q)  else put on exit_list
  */
     
  while ( q = entry_list )
  {
    entry_list = q->link ;

    if ( q->type == ST_NONE )
    { /* try to infer the type */
      /* it might now be in symbol table */
      if ( q->sym_p->type == ST_VAR )
      { /* set type and patch */
        q->type = CA_EXPR ;
        start[q->call_offset+1].ptr  = (PTR) q->sym_p->stval.cp ;
      }
      else
      if ( q->sym_p->type == ST_ARRAY )
      { q->type = CA_ARRAY ;
        start[q->call_offset].op = A_PUSHA ;
        start[q->call_offset+1].ptr = (PTR) q->sym_p->stval.array ;
      } 
      else /* try to infer from callee */
      {
        switch( callee->typev[q->arg_num] )
        {
          case  ST_LOCAL_VAR :
                q->type = CA_EXPR ;
                q->sym_p->type = ST_VAR ;
                q->sym_p->stval.cp = new_CELL() ;
                q->sym_p->stval.cp->type = C_NOINIT ;
                start[q->call_offset+1].ptr  = 
                         (PTR) q->sym_p->stval.cp ;
                break ;

          case  ST_LOCAL_ARRAY :
                q->type = CA_ARRAY ;
                q->sym_p->type = ST_ARRAY ;
                q->sym_p->stval.array = new_ARRAY() ;
                start[q->call_offset].op = A_PUSHA ;
                start[q->call_offset+1].ptr = 
                      (PTR) q->sym_p->stval.array ;
                break ;
        }
      }
    }
    else
    if ( q->type == ST_LOCAL_NONE )
    { /* try to infer the type */
      if ( * q->type_p == ST_LOCAL_VAR )
      { /* set type , don't need to patch */
        q->type = CA_EXPR ;
      }
      else
      if ( * q->type_p == ST_LOCAL_ARRAY )
      { q->type = CA_ARRAY ;
        start[q->call_offset].op = LA_PUSHA ;
        /* offset+1 op is OK */
      } 
      else /* try to infer from callee */
      {
        switch( callee->typev[q->arg_num] )
        {
          case  ST_LOCAL_VAR :
                q->type = CA_EXPR ;
                * q->type_p = ST_LOCAL_VAR ;
                /* do not need to patch */
                break ;

          case  ST_LOCAL_ARRAY :
                q->type = CA_ARRAY ;
                * q->type_p = ST_LOCAL_ARRAY ;
                start[q->call_offset].op = LA_PUSHA ;
                break ;
        }
      }
    }

    /* if we still do not know the type put on the new list
       else type check */

    if ( q->type == ST_NONE || q->type == ST_LOCAL_NONE )
    {
      q->link = exit_list ;
      exit_list = q ;
    }
    else  /* type known */
    {
      if ( callee->typev[q->arg_num] == ST_LOCAL_NONE )
           callee->typev[q->arg_num] = q->type ;

      else
      if ( q->type != callee->typev[q->arg_num] )
      {
        errmsg(0, "line %u: type error in arg(%d) in call to %s",
          line_no, q->arg_num+1, callee->name) ;
        if ( ++compile_error_count == MAX_COMPILE_ERRORS )
                    mawk_exit(1) ;
      }

      zfree(q, sizeof(CA_REC)) ;
      check_progress = 1 ;
    }
  } /* while */

  return  exit_list ;
}


static  int  arg_cnt_ok( fbp, q, line_no )
  FBLOCK  *fbp ;
  CA_REC  *q ;
  unsigned line_no ;
{
  if ( q->arg_num  >= fbp->nargs )
  {
    errmsg(0, "line %u: too many arguments in call to %s" ,
       line_no, fbp->name ) ;
    if ( ++compile_error_count == MAX_COMPILE_ERRORS ) 
              mawk_exit(1) ;

    return  0 ;
  }
  else  return 1 ;
}


FCALL_REC  *resolve_list ;
        /* function calls whose arg types need checking 
           are stored on this list */


/* on first pass thru the resolve list
   we check :
      if forward referenced functions were really defined
      if right number of arguments
   and compute call_start which is now known
*/

static  FCALL_REC *first_pass( p )
  register FCALL_REC *p ;
{ FCALL_REC dummy ;
  register FCALL_REC *q = &dummy ; /* trails p */

  q->link = p ;
  while ( p )
  {
    if ( ! p->callee->code )
    { /* callee never defined */
      errmsg(0, "line %u: function %s never defined" ,
          p->line_no, p->callee->name) ;
      if ( ++compile_error_count == MAX_COMPILE_ERRORS ) 
              mawk_exit(1) ;
      /* delete p from list */
      q->link = p->link ;
      /* don't worry about freeing memory, we'll exit soon */
    }
    else  /* note p->arg_list starts with last argument */
    if ( ! p->arg_list  /* nothing to do */  ||
         ! p->arg_cnt_checked && 
         ! arg_cnt_ok(p->callee, p->arg_list, p->line_no) )
    {  q->link = p->link ; /* delete p */ 
       /* the ! arg_list case is not an error so free memory */
       zfree(p, sizeof(FCALL_REC)) ;
    }
    else
    { /* keep p and set call_start */
      q = p ;
      switch ( p->call_scope )
      {
        case SCOPE_MAIN  :
                p->call_start = main_start ;
                break ;

        case SCOPE_BEGIN :
                p->call_start = begin_code.start ;
                break ;

        case SCOPE_END :
                p->call_start = end_code.start ;
                break ;

        case SCOPE_FUNCT :
                p->call_start = p->call->code ;
                break ;
      }
    }
    p = q->link ;
  }
  return  dummy.link ;
}

/* continuously walk the resolve_list making type deductions
   until this list goes empty or no more progress can be made
   (An example where no more progress can be made is at end of file
*/

void  resolve_fcalls()
{ register FCALL_REC *p, *old_list , *new_list ;
  int progress ; /* a flag */

  old_list = first_pass(resolve_list) ;
  new_list = (FCALL_REC *) 0 ;
  progress = 0 ;

  while ( 1 )
  {
    if ( !(p = old_list) )
    { /* flop the lists */
      if ( !(p = old_list = new_list)  /* nothing left */
          || ! progress    /* can't do any more */ )  return ;

      /* reset after flop */
      new_list = (FCALL_REC *) 0 ;  progress = 0 ;
    }

    old_list = p->link ;

    if ( p->arg_list = call_arg_check(p->callee, p->arg_list ,
              p->call_start, p->line_no)  )
    {
       /* still have work to do , put on new_list   */
       progress  |= check_progress ;
       p->link = new_list ;  new_list = p ;
    }
    else  /* done with p */
    {  progress = 1 ;  zfree(p, sizeof(FCALL_REC)) ; }
  }
}

/* the parser has just reduced a function call ;
   the info needed to type check is passed in.  If type checking
   can not be done yet (most common reason -- function referenced
   but not defined), a node is added to the resolve list.
*/
void check_fcall( callee, call_scope, call, arg_list, line_no )
  FBLOCK *callee ;
  int call_scope ;
  FBLOCK  *call ;
  CA_REC  *arg_list ;
  unsigned line_no ;
{
  FCALL_REC *p ;
  INST *call_start ;

  if ( ! callee->code ) 
  { /* forward reference to a function to be defined later */
    p = (FCALL_REC *) zmalloc(sizeof(FCALL_REC)) ;
    p->callee = callee ;
    p->call_scope = call_scope ;
    p->call = call ;
    p->arg_list = arg_list ;
    p->arg_cnt_checked = 0 ;
    p->line_no = line_no ;
    /* add to resolve list */
    p->link = resolve_list ; resolve_list = p ;
  }
  else
  if ( arg_list && arg_cnt_ok( callee, arg_list, line_no ) )
  {
      switch ( call_scope )
      {
        case SCOPE_MAIN  :
                call_start = main_start ;
                break ;

        case SCOPE_BEGIN :
                call_start = begin_code.start ;
                break ;

        case SCOPE_END :
                call_start = end_code.start ;
                break ;

        case SCOPE_FUNCT :
                call_start = call->code ;
                break ;
      }

      /* usually arg_list disappears here and all is well
         otherwise add to resolve list */

      if ( arg_list = call_arg_check(callee, arg_list,
                call_start, line_no) )
      {
            p = (FCALL_REC *) zmalloc(sizeof(FCALL_REC)) ;
            p->callee = callee ;
            p->call_scope = call_scope ;
            p->call = call ;
            p->arg_list = arg_list ;
            p->arg_cnt_checked = 1 ;
            p->line_no = line_no ;
            /* add to resolve list */
            p->link = resolve_list ; resolve_list = p ;
      }
  }
}



/*  example where typing cannot progress

{ f(z) }

function f(x) { print NR }

# this is legal, does something useful, but absurdly written
# We have to design so this works
*/