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Annotation of 43BSDTahoe/ucb/pascal/pdx/sym/which.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1980 Regents of the University of California.
                      3:  * All rights reserved.  The Berkeley software License Agreement
                      4:  * specifies the terms and conditions for redistribution.
                      5:  */
                      6: 
                      7: #ifndef lint
                      8: static char sccsid[] = "@(#)which.c    5.1 (Berkeley) 6/6/85";
                      9: #endif not lint
                     10: 
                     11: /*
                     12:  * Routines to distinguish symbols of the same name.
                     13:  */
                     14: 
                     15: #include "defs.h"
                     16: #include "sym.h"
                     17: #include "classes.h"
                     18: #include "symtab.h"
                     19: #include "mappings.h"
                     20: #include "machine.h"
                     21: #include "sym.rep"
                     22: 
                     23: /*
                     24:  * Figure out the "current" symbol being referred to,
                     25:  * this is either the active one or the most visible from the
                     26:  * current scope.
                     27:  *
                     28:  * Fields are purposely ignored; these can be gotten to via "findclass".
                     29:  */
                     30: 
                     31: SYM *which(s)
                     32: SYM *s;
                     33: {
                     34:        register SYM *p, *t, *f;
                     35: 
                     36:        if (s == program || isbuiltin(s)) {
                     37:                return(s);
                     38:        }
                     39:        if (!isactive(program)) {
                     40:                f = program;
                     41:        } else {
                     42:                f = whatblock(pc);
                     43:                if (f == NIL) {
                     44:                        panic("no block for addr 0x%x", pc);
                     45:                }
                     46:        }
                     47:        for (p = f; p != NIL; p = p->func) {
                     48:                if ((t = findsym(s, p)) != NIL) {
                     49:                        break;
                     50:                }
                     51:        }
                     52:        if (t == NIL) {
                     53:                error("\"%s\" is not known in \"%s\"", s->symbol, f->symbol);
                     54:        }
                     55:        return(t);
                     56: }
                     57: 
                     58: /*
                     59:  * Find a (non-field) symbol with name s->symbol belonging to block f.
                     60:  *
                     61:  * Parameters to the main program are purposely "not found" because
                     62:  * pi gives them no type.
                     63:  */
                     64: 
                     65: SYM *findsym(s, f)
                     66: SYM *s;
                     67: SYM *f;
                     68: {
                     69:        register SYM *t;
                     70: 
                     71:        if (!isblock(f)) {
                     72:                error("%s is not a block", f->symbol);
                     73:        }
                     74:        for (t = s; t != NIL; t = t->next_sym) {
                     75:                if (t->func == f && !(f == program && isparam(t)) &&
                     76:                  t->class != FIELD && streq(t->symbol, s->symbol)) {
                     77:                        break;
                     78:                }
                     79:        }
                     80:        return(t);
                     81: }
                     82: 
                     83: /*
                     84:  * Find the symbol which is has the same name and scope as the
                     85:  * given symbol but is of the given field.  Return NIL if there is none.
                     86:  */
                     87: 
                     88: SYM *findclass(s, cl)
                     89: SYM *s;
                     90: char cl;
                     91: {
                     92:        register SYM *t;
                     93: 
                     94:        if (s->class == cl) {
                     95:                return(s);
                     96:        }
                     97:        t = st_lookup(symtab, s->symbol);
                     98:        while (t != NIL && (t->class != cl || t->func != s->func ||
                     99:          !streq(s->symbol, t->symbol))) {
                    100:                t = t->next_sym;
                    101:        }
                    102:        return(t);
                    103: }

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