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dwarf: Avoid a leak for a no-cache failure in create_state_record_for.

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Avoid a duplicate copy for a cache miss.
This commit is contained in:
Doug Moore 2017-04-27 15:44:01 -05:00 committed by Dave Watson
parent 24ac32b480
commit 3775cdd997
1 changed files with 23 additions and 49 deletions
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72
src/dwarf/Gparser.c
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@ -874,46 +874,19 @@ apply_reg_state (struct dwarf_cursor *c, struct dwarf_reg_state *rs)
return 0; return 0;
} }
static int
uncached_dwarf_find_save_locs (struct dwarf_cursor *c)
{
dwarf_state_record_t sr;
int ret;
if ((ret = fetch_proc_info (c, c->ip, 1)) < 0)
{
put_unwind_info (c, &c->pi);
return ret;
}
if ((ret = create_state_record_for (c, &sr, c->ip)) < 0)
return ret;
if ((ret = apply_reg_state (c, &sr.rs_current)) < 0)
return ret;
put_unwind_info (c, &c->pi);
return 0;
}
/* The function finds the saved locations and applies the register /* The function finds the saved locations and applies the register
state as well. */ state as well. */
HIDDEN int HIDDEN int
dwarf_find_save_locs (struct dwarf_cursor *c) dwarf_find_save_locs (struct dwarf_cursor *c)
{ {
dwarf_state_record_t sr; dwarf_state_record_t sr;
dwarf_reg_state_t *rs, rs_copy; dwarf_reg_state_t *rs;
struct dwarf_rs_cache *cache; struct dwarf_rs_cache *cache;
int ret = 0; int ret = 0;
intrmask_t saved_mask; intrmask_t saved_mask;
if (c->as->caching_policy == UNW_CACHE_NONE) if ((cache = get_rs_cache(c->as, &saved_mask)) &&
return uncached_dwarf_find_save_locs (c); (rs = rs_lookup(cache, c)))
cache = get_rs_cache(c->as, &saved_mask);
rs = rs_lookup(cache, c);
if (rs)
{ {
/* update hint; no locking needed: single-word writes are atomic */ /* update hint; no locking needed: single-word writes are atomic */
cache->buckets[c->prev_rs].hint = rs - cache->buckets + 1; cache->buckets[c->prev_rs].hint = rs - cache->buckets + 1;
@ -921,31 +894,32 @@ dwarf_find_save_locs (struct dwarf_cursor *c)
c->hint = rs->hint; c->hint = rs->hint;
c->ret_addr_column = rs->ret_addr_column; c->ret_addr_column = rs->ret_addr_column;
c->use_prev_instr = ! rs->signal_frame; c->use_prev_instr = ! rs->signal_frame;
memcpy (&sr.rs_current, rs, sizeof (*rs));
} }
else else
{ {
if ((ret = fetch_proc_info (c, c->ip, 1)) < 0 || ret = fetch_proc_info (c, c->ip, 1);
(ret = create_state_record_for (c, &sr, c->ip)) < 0) if (ret >= 0)
{ ret = create_state_record_for (c, &sr, c->ip);
put_rs_cache (c->as, cache, &saved_mask);
put_unwind_info (c, &c->pi);
return ret;
}
rs = rs_new (cache, c);
memcpy(rs, &sr.rs_current, offsetof(struct dwarf_reg_state, ip));
cache->buckets[c->prev_rs].hint = rs - cache->buckets;
c->prev_rs = rs - cache->buckets;
c->hint = rs->hint = 0;
put_unwind_info (c, &c->pi); put_unwind_info (c, &c->pi);
if (cache && ret >= 0)
{
rs = rs_new (cache, c);
memcpy(rs, &sr.rs_current, offsetof(struct dwarf_reg_state, ip));
cache->buckets[c->prev_rs].hint = rs - cache->buckets;
c->prev_rs = rs - cache->buckets;
c->hint = rs->hint = 0;
}
} }
memcpy (&rs_copy, rs, sizeof (rs_copy)); if (cache)
put_rs_cache (c->as, cache, &saved_mask); put_rs_cache (c->as, cache, &saved_mask);
if (ret < 0)
tdep_reuse_frame (c, &rs_copy); return ret;
if ((ret = apply_reg_state (c, &rs_copy)) < 0) if (cache)
tdep_reuse_frame (c, rs);
if ((ret = apply_reg_state (c, &sr.rs_current)) < 0)
return ret; return ret;
return 0; return 0;