shithub: scc

ref: bae05fff3765490d73e5e69945d2ff9a5ffdb2ee
dir: /symbol.c/

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include "cc.h"
#include "symbol.h"
#include "tokens.h"

#define NR_SYM_HASH 32

unsigned char curctx;

static struct symbol *htab[NR_SYM_HASH];
static struct symbol *head, *headfun;


unsigned char
hash(register const char *s)
{
	register unsigned char h, ch;

	for (h = 0; ch = *s++; h += ch)
		/* nothing */;
	return h;
}

void
new_ctx(void)
{
	++curctx;
}

void
del_ctx(void)
{
	register struct symbol *sym, *next;
	static char *s;

	for (sym = head; sym; sym = next) {
		if (sym->ctx <= curctx)
			break;
		if ((s = sym->name) != NULL)
			htab[hash(s) & NR_SYM_HASH - 1] = sym->hash;
		next = sym->next;
		sym->next = headfun;
		headfun = sym;
	}
	--curctx;
}

void
freesyms(void)
{
	register struct symbol *sym, *next;

	if (curctx == CTX_OUTER) {
		for (sym = headfun; sym; sym = next) {
			next = sym->next;
			free(sym->name);
			free(sym);
		}
	}
}

struct symbol *
lookup(register const char *s, signed char ns)
{
	register struct symbol *sym;
	static unsigned char key;
	register char *t;

	if (s == NULL) {
		sym = xcalloc(1, sizeof(*sym));
		sym->next = head;
		return sym;
	}

	key = hash(s) & NR_SYM_HASH - 1;
	for (sym = htab[key]; sym; sym = sym->hash) {
		t = sym->name;
		if (ns == sym->ns && *t == *s && !strcmp(t, s))
			return sym;
	}

	sym = xcalloc(1, sizeof(*sym));
	sym->name = xstrdup(s);
	sym->next = head;
	sym->ctx = curctx;
	sym->ns = ns;
	sym->tok = IDEN;
	head = sym;
	sym->hash = htab[key];
	htab[key] = sym;

	return sym;
}

void
insert(struct symbol *sym, unsigned char ctx)
{
	register struct symbol *p, *q;

	for (q = p = head; p; q = p, p = p->next) {
		if (p == sym)
			break;
	}
	assert(p);			/* sym must be in the list */
	q->next = p->next;		/* remove from the list */

	for (q = p = head; p; q = p, p = p->next) {
		if (p->ctx <= ctx)
			break;
	}
	if (q == NULL) {
		head = sym;
		sym->next = NULL;
	} else {
		q->next = sym;
		sym->next = p;
	}
}