282 lines
6.8 KiB
C
282 lines
6.8 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Header$ */
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/* S T A C K / U N S T A C K R O U T I N E S */
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#include "lint.h"
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#include "nofloat.h"
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#include <system.h>
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#ifndef LINT
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#include <em.h>
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#else
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#include "l_em.h"
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#endif /* LINT */
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#include "debug.h"
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#include "botch_free.h"
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#include <alloc.h>
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#include "Lpars.h"
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#include "arith.h"
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#include "stack.h"
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#include "type.h"
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#include "idf.h"
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#include "def.h"
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#include "struct.h"
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#include "level.h"
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#include "mes.h"
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#include "noRoption.h"
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extern char options[];
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static struct stack_level UniversalLevel;
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struct stack_level *local_level = &UniversalLevel;
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/* The main reason for having this secondary stacking
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mechanism besides the linked lists pointed to by the idf's
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is efficiency.
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To remove the idf's of a given level, one could scan the
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hash table and chase down the idf chains; with a hash
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table size of 100 this is feasible, but with a size of say
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100000 this becomes painful. Therefore all idf's are also
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kept in a stack of sets, one set for each level.
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*/
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int level; /* Always equal to local_level->sl_level. */
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stack_level() {
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/* A new level is added on top of the identifier stack.
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*/
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register struct stack_level *stl = new_stack_level();
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register struct stack_level *loclev = local_level;
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loclev->sl_next = stl;
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stl->sl_previous = loclev;
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stl->sl_level = ++level;
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stl->sl_max_block = loclev->sl_max_block;
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local_level = stl;
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#ifdef LINT
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lint_start_local();
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#endif /* LINT */
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}
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stack_idf(idf, stl)
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struct idf *idf;
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register struct stack_level *stl;
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{
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/* The identifier idf is inserted in the stack on level stl.
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*/
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register struct stack_entry *se = new_stack_entry();
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/* link it into the stack level */
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se->next = stl->sl_entry;
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se->se_idf = idf;
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stl->sl_entry = se;
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}
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struct stack_level *
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stack_level_of(lvl)
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{
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/* The stack_level corresponding to level lvl is returned.
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The stack should probably be an array, to be extended with
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realloc where needed.
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*/
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register struct stack_level *stl;
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if (lvl == level)
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return local_level;
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stl = &UniversalLevel;
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while (stl->sl_level != lvl)
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stl = stl->sl_next;
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return stl;
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}
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unstack_level()
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{
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/* The top level of the identifier stack is removed.
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*/
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struct stack_level *lastlvl;
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#ifdef DEBUG
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if (options['t'])
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dumpidftab("before unstackidfs", 0);
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#endif /* DEBUG */
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#ifdef LINT
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lint_end_local(local_level);
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#endif /* LINT */
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/* The implementation below is more careful than strictly
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necessary. Optimists may optimize it afterwards.
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*/
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while (local_level->sl_entry) {
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register struct stack_entry *se = local_level->sl_entry;
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register struct idf *idf = se->se_idf;
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register struct def *def;
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register struct sdef *sdef;
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register struct tag *tag;
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/* unlink it from the local stack level */
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local_level->sl_entry = se->next;
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free_stack_entry(se);
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while ((def = idf->id_def) && def->df_level >= level) {
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/* unlink it from the def list under the idf block */
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if (def->df_sc == LABEL)
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unstack_label(idf);
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else if (def->df_sc == REGISTER || def->df_sc == AUTO)
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FreeLocal(def->df_address);
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idf->id_def = def->next;
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free_def(def);
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update_ahead(idf);
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}
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while ( (sdef = idf->id_sdef)
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&& sdef->sd_level >= level
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) {
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/* unlink it from the sdef list under the idf block */
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idf->id_sdef = sdef->next;
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free_sdef(sdef);
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}
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while ( (tag = idf->id_struct)
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&& tag->tg_level >= level
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) {
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/* unlink it from the struct list under the idf block */
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idf->id_struct = tag->next;
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free_tag(tag);
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}
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while ((tag = idf->id_enum) && tag->tg_level >= level) {
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/* unlink it from the enum list under the idf block */
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idf->id_enum = tag->next;
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free_tag(tag);
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}
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}
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/* Unlink the local stack level from the stack.
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*/
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lastlvl = local_level;
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local_level = local_level->sl_previous;
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if (level >= L_LOCAL) {
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local_level->sl_max_block = lastlvl->sl_max_block;
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}
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free_stack_level(lastlvl);
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local_level->sl_next = (struct stack_level *) 0;
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level = local_level->sl_level;
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#ifdef DEBUG
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if (options['t'])
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dumpidftab("after unstackidfs", 0);
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#endif /* DEBUG */
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}
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unstack_world()
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{
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/* The global level of identifiers is scanned, and final
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decisions are taken about such issues as
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extern/static/global and un/initialized.
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Effects on the code generator: initialised variables
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have already been encoded while the uninitialised ones
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are not and have to be encoded at this moment.
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*/
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register struct stack_entry *se = local_level->sl_entry;
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#ifdef LINT
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lint_end_global(local_level);
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#endif /* LINT */
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open_name_list();
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while (se) {
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register struct idf *idf = se->se_idf;
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register struct def *def = idf->id_def;
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if (!def) {
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/* global selectors, etc. */
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se = se->next;
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continue;
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}
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#ifdef DEBUG
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if (options['a']) {
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char *symbol2str();
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print("\"%s\", %s, %s, %s, %s\n",
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idf->id_text,
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(def->df_alloc == 0) ? "no alloc" :
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(def->df_alloc == ALLOC_SEEN) ? "alloc seen" :
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(def->df_alloc == ALLOC_DONE) ? "alloc done" :
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"illegal alloc info",
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symbol2str(def->df_sc),
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def->df_initialized ? "init" : "no init",
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def->df_used ? "used" : "not used");
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}
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#endif /* DEBUG */
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/*
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/_* find final storage class *_/
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if (def->df_sc == GLOBAL || def->df_sc == IMPLICIT)
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/_* even now we still don't know *_/
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def->df_sc = EXTERN;
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*/
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if ( def->df_sc == STATIC
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&& def->df_type->tp_fund == FUNCTION
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&& !def->df_initialized
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) {
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/* orphaned static function */
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#ifndef NOROPTION
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if (options['R'])
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warning("static function %s never defined, %s",
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idf->id_text,
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"changed to extern"
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);
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#endif
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def->df_sc = EXTERN;
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}
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if (
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def->df_alloc == ALLOC_SEEN &&
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!def->df_initialized
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) {
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/* space must be allocated */
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bss(idf);
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if (def->df_sc != STATIC)
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namelist(idf->id_text); /* may be common */
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def->df_alloc = ALLOC_DONE; /* see Note below */
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}
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se = se->next;
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}
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/* Note:
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df_alloc must be set to ALLOC_DONE because the idf entry
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may occur several times in the list.
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The reason for this is that the same name may be used
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for different purposes on the same level, e.g.
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struct s {int s;} s;
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is a legal definition and contains 3 defining occurrences
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of s.
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Each definition has been entered into the identifier stack.
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Although only one of them concerns a variable, we meet the
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s 3 times when scanning the identifier stack.
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*/
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}
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/* A list of potential common names is kept, to be fed to
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an understanding loader. The list is written to a file
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the name of which is nmlist. If nmlist == NULL, no name
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list is generated.
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*/
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extern char *nmlist; /* BAH! -- main.c */
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static File *nfp = 0;
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open_name_list()
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{
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if (nmlist && sys_open(nmlist, OP_WRITE, &nfp) == 0)
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fatal("cannot create namelist %s", nmlist);
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}
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namelist(nm)
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char *nm;
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{
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if (nmlist) {
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sys_write(nfp, nm, strlen(nm));
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sys_write(nfp, "\n", 1);
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}
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}
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