ack/mach/proto/cg/salloc.c
2019-05-11 01:11:54 +08:00

143 lines
2.6 KiB
C

/*
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*
* Author: Hans van Staveren
*/
#include <stdlib.h>
#include "assert.h"
#include "param.h"
#include "tables.h"
#include "types.h"
#include <cg_pattern.h>
#include "data.h"
#include "result.h"
#include "extern.h"
#include "subr.h"
#include "salloc.h"
/*
* Package for string allocation and garbage collection.
* Call salloc(size) to get room for string.
* Every now and then call garbage_collect() from toplevel.
*/
#define MAXSTAB 2500
#define THRESHOLD 200
char *stab[MAXSTAB];
int nstab=0;
static void chkstr(string str,char used[])
{
register int low,middle,high;
low=0; high=nstab-1;
while (high>low) {
middle= (low+high)>>1;
if (str==stab[middle]) {
used[middle]=1;
return;
}
if (str<stab[middle])
high = middle-1;
else
low = middle+1;
}
if (low==high) {
if (str==stab[low]) {
used[low]=1;
}
return;
}
}
string myalloc(int size)
{
register string p;
p = (string) malloc(size);
if (p==0)
fatal("Out of memory");
return(p);
}
void myfree(void* p)
{
free(p);
}
void popstr(int nnstab)
{
register int i;
for (i=nnstab;i<nstab;i++)
myfree(stab[i]);
nstab = nnstab;
}
char *salloc(int size)
{
register char *p;
if (nstab==MAXSTAB)
fatal("String table overflow");
p = myalloc(size+1); /* extra room for terminating zero */
stab[nstab++] = p;
return(p);
}
int compar(char **p1, char **p2)
{
assert(*p1 != *p2);
if (*p1 < *p2)
return(-1);
return(1);
}
void garbage_collect(void) {
register int i;
struct emline *emlp;
token_p tp;
tkdef_p tdp;
struct reginfo *rp;
register char **fillp,**scanp;
char used[MAXSTAB]; /* could be bitarray */
if (nstab<THRESHOLD)
return;
qsort(stab,nstab,sizeof (char *),compar);
for (i=0;i<nstab;i++)
used[i]= FALSE;
for(emlp=emlines;emlp<emlines+nemlines;emlp++)
chkstr(emlp->em_soper,used);
for (tp= fakestack;tp<&fakestack[stackheight];tp++) {
if (tp->t_token== -1)
continue;
tdp = &tokens[tp->t_token];
for (i=0;i<TOKENSIZE;i++)
if (tdp->t_type[i] == EV_STR)
chkstr(tp->t_att[i].as,used);
}
for (rp= machregs; rp<machregs+NREGS; rp++) {
tp = &rp->r_contents;
assert(tp->t_token != -1);
tdp= &tokens[tp->t_token];
for (i=0;i<TOKENSIZE;i++)
if (tdp->t_type[i] == EV_STR)
chkstr(tp->t_att[i].as,used);
}
for (i=0;i<nstab;i++)
if (!used[i]) {
myfree(stab[i]);
stab[i]=0;
}
fillp=stab;
for (scanp=stab;scanp<stab+nstab;scanp++)
if (*scanp != 0)
*fillp++ = *scanp;
nstab = fillp-stab;
}