ack/lang/cem/cemcom/stack.c

294 lines
7 KiB
C

/* $Header$ */
/* S T A C K / U N S T A C K R O U T I N E S */
#include "nofloat.h"
#include <system.h>
#include <em.h>
#include <em_reg.h>
#include "debug.h"
#include "use_tmp.h"
#include "botch_free.h"
#include "alloc.h"
#include "Lpars.h"
#include "arith.h"
#include "stack.h"
#include "type.h"
#include "idf.h"
#include "def.h"
#include "struct.h"
#include "storage.h"
#include "level.h"
#include "mes.h"
/* #include <em_reg.h> */
extern char options[];
static struct stack_level UniversalLevel;
struct stack_level *local_level = &UniversalLevel;
/* The main reason for having this secondary stacking
mechanism besides the linked lists pointed to by the idf's
is efficiency.
To remove the idf's of a given level, one could scan the
hash table and chase down the idf chains; with a hash
table size of 100 this is feasible, but with a size of say
100000 this becomes painful. Therefore all idf's are also
kept in a stack of sets, one set for each level.
*/
int level; /* Always equal to local_level->sl_level. */
stack_level() {
/* A new level is added on top of the identifier stack.
*/
register struct stack_level *stl = new_stack_level();
clear((char *)stl, sizeof(struct stack_level));
local_level->sl_next = stl;
stl->sl_previous = local_level;
stl->sl_level = ++level;
stl->sl_local_offset =
stl->sl_max_block = local_level->sl_local_offset;
local_level = stl;
}
stack_idf(idf, stl)
struct idf *idf;
register struct stack_level *stl;
{
/* The identifier idf is inserted in the stack on level stl.
*/
register struct stack_entry *se = new_stack_entry();
clear((char *)se, sizeof(struct stack_entry));
/* link it into the stack level */
se->next = stl->sl_entry;
se->se_idf = idf;
stl->sl_entry = se;
}
struct stack_level *
stack_level_of(lvl)
{
/* The stack_level corresponding to level lvl is returned.
The stack should probably be an array, to be extended with
realloc where needed.
*/
if (lvl == level)
return local_level;
else {
register struct stack_level *stl = &UniversalLevel;
while (stl->sl_level != lvl)
stl = stl->sl_next;
return stl;
}
/*NOTREACHED*/
}
unstack_level()
{
/* The top level of the identifier stack is removed.
*/
struct stack_level *lastlvl;
#ifdef DEBUG
if (options['t'])
dumpidftab("before unstackidfs", 0);
#endif DEBUG
/* The implementation below is more careful than strictly
necessary. Optimists may optimize it afterwards.
*/
while (local_level->sl_entry) {
register struct stack_entry *se = local_level->sl_entry;
register struct idf *idf = se->se_idf;
register struct def *def;
register struct sdef *sdef;
register struct tag *tag;
/* unlink it from the local stack level */
local_level->sl_entry = se->next;
free_stack_entry(se);
while ((def = idf->id_def) && def->df_level >= level) {
/* unlink it from the def list under the idf block */
if (def->df_sc == LABEL)
unstack_label(idf);
else
if (level == L_LOCAL || level == L_FORMAL1) {
if ( def->df_register != REG_NONE &&
def->df_sc != STATIC &&
options['n'] == 0
) {
int reg;
switch (def->df_type->tp_fund) {
case POINTER:
reg = reg_pointer;
break;
#ifndef NOFLOAT
case FLOAT:
case DOUBLE:
reg = reg_float;
break;
#endif NOFLOAT
default:
reg = reg_any;
break;
}
C_ms_reg(def->df_address,
def->df_type->tp_size,
reg, def->df_register
);
}
}
idf->id_def = def->next;
free_def(def);
update_ahead(idf);
}
while ( (sdef = idf->id_sdef)
&& sdef->sd_level >= level
) {
/* unlink it from the sdef list under the idf block */
idf->id_sdef = sdef->next;
free_sdef(sdef);
}
while ( (tag = idf->id_struct)
&& tag->tg_level >= level
) {
/* unlink it from the struct list under the idf block */
idf->id_struct = tag->next;
free_tag(tag);
}
while ((tag = idf->id_enum) && tag->tg_level >= level) {
/* unlink it from the enum list under the idf block */
idf->id_enum = tag->next;
free_tag(tag);
}
}
/* Unlink the local stack level from the stack.
*/
lastlvl = local_level;
local_level = local_level->sl_previous;
if ( level > L_LOCAL
&& lastlvl->sl_max_block < local_level->sl_max_block
) {
local_level->sl_max_block = lastlvl->sl_max_block;
}
free_stack_level(lastlvl);
local_level->sl_next = (struct stack_level *) 0;
level = local_level->sl_level;
#ifdef DEBUG
if (options['t'])
dumpidftab("after unstackidfs", 0);
#endif DEBUG
}
unstack_world()
{
/* The global level of identifiers is scanned, and final
decisions are taken about such issues as
extern/static/global and un/initialized.
Effects on the code generator: initialised variables
have already been encoded while the uninitialised ones
are not and have to be encoded at this moment.
*/
register struct stack_entry *se = local_level->sl_entry;
open_name_list();
while (se) {
register struct idf *idf = se->se_idf;
register struct def *def = idf->id_def;
if (!def) {
/* global selectors, etc. */
se = se->next;
continue;
}
#ifdef DEBUG
if (options['a']) {
char *symbol2str();
print("\"%s\", %s, %s, %s, %s\n",
idf->id_text,
(def->df_alloc == 0) ? "no alloc" :
(def->df_alloc == ALLOC_SEEN) ? "alloc seen" :
(def->df_alloc == ALLOC_DONE) ? "alloc done" :
"illegal alloc info",
symbol2str(def->df_sc),
def->df_initialized ? "init" : "no init",
def->df_used ? "used" : "not used");
}
#endif DEBUG
/*
/_* find final storage class *_/
if (def->df_sc == GLOBAL || def->df_sc == IMPLICIT)
/_* even now we still don't know *_/
def->df_sc = EXTERN;
*/
if ( def->df_sc == STATIC
&& def->df_type->tp_fund == FUNCTION
&& !def->df_initialized
) {
/* orphaned static function */
if (options['R'])
warning("static function %s never defined, %s",
idf->id_text,
"changed to extern"
);
def->df_sc = EXTERN;
}
if (
def->df_alloc == ALLOC_SEEN &&
!def->df_initialized
) {
/* space must be allocated */
bss(idf);
namelist(idf->id_text); /* may be common */
def->df_alloc = ALLOC_DONE; /* see Note below */
}
se = se->next;
}
/* Note:
df_alloc must be set to ALLOC_DONE because the idf entry
may occur several times in the list.
The reason for this is that the same name may be used
for different purposes on the same level, e.g.
struct s {int s;} s;
is a legal definition and contains 3 defining occurrences
of s.
Each definition has been entered into the identifier stack.
Although only one of them concerns a variable, we meet the
s 3 times when scanning the identifier stack.
*/
}
/* A list of potential common names is kept, to be fed to
an understanding loader. The list is written to a file
the name of which is nmlist. If nmlist == NULL, no name
list is generated.
*/
extern char *nmlist; /* BAH! -- main.c */
static File *nfp = 0;
open_name_list()
{
if (nmlist && sys_open(nmlist, OP_WRITE, &nfp) == 0)
fatal("cannot create namelist %s", nmlist);
}
namelist(nm)
char *nm;
{
if (nmlist) {
sys_write(nfp, nm, strlen(nm));
sys_write(nfp, "\n", 1);
}
}