Author: sewardj
Date: 2008-03-04 11:26:51 +0000 (Tue, 04 Mar 2008)
New Revision: 7556
Log:
memory_state_machine(): move unlikely cases to the end of the decision
tree, and add branch hints.
Modified:
branches/HGDEV/helgrind/hg_main.c
Modified: branches/HGDEV/helgrind/hg_main.c
===================================================================
--- branches/HGDEV/helgrind/hg_main.c 2008-03-04 01:58:47 UTC (rev 7555)
+++ branches/HGDEV/helgrind/hg_main.c 2008-03-04 11:26:51 UTC (rev 7556)
@@ -3046,21 +3046,18 @@
static
SVal memory_state_machine(Bool is_w, Thread* thr, Addr a, SVal sv_old, Int sz)
{
- Bool hb_all = False;
- UWord oldSS_size = 0;
- Bool was_w, now_w;
+ UWord i;
+ Bool was_w, now_w;
SegmentSet oldSS;
LockSet oldLS;
- Bool is_race = False;
- SVal sv_new = SHVAL_Invalid;
- Bool do_trace = clo_trace_level > 0
- && a >= clo_trace_addr
- && a < (clo_trace_addr+sz);
-
+ Bool hb_all = False;
+ UWord oldSS_size = 0;
+ Bool is_race = False;
+ SVal sv_new = SHVAL_Invalid;
+ Bool do_trace = clo_trace_level > 0
+ && a >= clo_trace_addr
+ && a < (clo_trace_addr+sz);
SegmentID currS = thr->csegid;
-
-
- UWord i;
SegmentSet newSS = 0;
LockSet newLS = 0;
@@ -3068,14 +3065,13 @@
LockSet currLS = is_w ? thr->locksetW
: thr->locksetA;
- if (sv_old == SHVAL_Race) {
+ if (UNLIKELY(sv_old == SHVAL_Race)) {
// we already reported a race, don't bother again.
sv_new = sv_old;
goto done;
}
-
- if (__bus_lock_Lock->heldBy
+ if (UNLIKELY(__bus_lock_Lock->heldBy)
&& (is_SHVAL_New(sv_old) || is_SHVAL_R(sv_old))) {
// BHL is held and we are in 'Read' or 'New' state.
// User is doing something very smart with LOCK prefix.
@@ -3097,18 +3093,67 @@
// - Any other write is a race.
}
+ tl_assert(is_sane_Thread(thr));
+ // Read or Write
+ if (LIKELY(is_SHVAL_RW(sv_old))) {
+ was_w = is_SHVAL_W(sv_old);
+ oldSS = get_SHVAL_SS(sv_old);
+ oldLS = get_SHVAL_LS(sv_old);
- tl_assert(is_sane_Thread(thr));
+ oldSS_size = SS_get_size(oldSS);
+ // update the segment set and compute hb_all
+ hb_all = True;
+ newSS = SS_mk_singleton(currS);
+ for (i = 0; i < oldSS_size; i++) {
+ SegmentID S = SS_get_element(oldSS, i);
+ Bool hb = False;
+ if (S == currS // Same segment.
+ || SEG_get(S)->thr == thr // Same thread.
+ || happens_before(S, currS)) {
+ // different thread, but happens-before
+ hb = True;
+ }
+ if (do_trace) {
+ VG_(printf)("HB(S%d/T%d,cur)=%d\n",
+ S, SEG_get(S)->thr->errmsg_index, hb);
+ }
- // NoAccess
- if (is_SHVAL_NoAccess(sv_old)) {
- // TODO: complain
- sv_new = sv_old;
+ if (!hb) {
+ hb_all = False;
+ // Not happened-before. Leave this segment in SS.
+ if (SS_is_singleton(newSS)) {
+ tl_assert(currS != S);
+ newSS = HG_(doubletonWS)(univ_ssets, currS, S);
+ } else {
+ newSS = HG_(addToWS)(univ_ssets, newSS, S);
+ }
+ }
+ }
+
+ // update lock set.
+ if (hb_all) {
+ newLS = currLS;
+ } else {
+ newLS = HG_(intersectWS)(univ_lsets, oldLS, currLS);
+ }
+
+ // update the state
+ now_w = is_w || (was_w && !hb_all);
+
+ // generate new SVal
+ sv_new = mk_SHVAL_RW(now_w, newSS, newLS);
+
+ is_race = now_w && !SS_is_singleton(newSS)
+ && HG_(isEmptyWS)(univ_lsets, newLS);
+
+ if (oldLS != newLS) {
+ // if the lockset changed, remember when it happened
+ record_last_lock_lossage(a, oldLS, newLS);
+ }
goto done;
}
-
// New
if (is_SHVAL_New(sv_old)) {
newSS = SS_mk_singleton(currS);
@@ -3116,69 +3161,20 @@
goto done;
}
-
- // Read or Write
- tl_assert(is_SHVAL_RW(sv_old));
- was_w = is_SHVAL_W(sv_old);
- oldSS = get_SHVAL_SS(sv_old);
- oldLS = get_SHVAL_LS(sv_old);
-
-
- oldSS_size = SS_get_size(oldSS);
- // update the segment set and compute hb_all
- hb_all = True;
- newSS = SS_mk_singleton(currS);
- for (i = 0; i < oldSS_size; i++) {
- SegmentID S = SS_get_element(oldSS, i);
- Bool hb = False;
- if (S == currS // Same segment.
- || SEG_get(S)->thr == thr // Same thread.
- || happens_before(S, currS)) { // different thread, but
happens-before
- hb = True;
- }
- if (do_trace) {
- VG_(printf)("HB(S%d/T%d,cur)=%d\n",
- S, SEG_get(S)->thr->errmsg_index, hb);
- }
-
- if(!hb) {
- hb_all = False;
- // Not happened-before. Leave this segment in SS.
- if (SS_is_singleton(newSS)) {
- tl_assert(currS != S);
- newSS = HG_(doubletonWS)(univ_ssets, currS, S);
- } else {
- newSS = HG_(addToWS)(univ_ssets, newSS, S);
- }
- }
- }
-
- // update lock set.
- if (hb_all) {
- newLS = currLS;
- } else {
- newLS = HG_(intersectWS)(univ_lsets, oldLS, currLS);
+ // NoAccess
+ if (is_SHVAL_NoAccess(sv_old)) {
+ // TODO: complain
+ sv_new = sv_old;
+ goto done;
}
- // update the state
- now_w = is_w || (was_w && !hb_all);
+ /*NOTREACHED*/
+ tl_assert(0);
- // generate new SVal
- sv_new = mk_SHVAL_RW(now_w, newSS, newLS);
-
- is_race = now_w
- && !SS_is_singleton(newSS)
- && HG_(isEmptyWS)(univ_lsets, newLS);
-
- if (oldLS != newLS) {
- // if the lockset changed, remember when it happened
- record_last_lock_lossage(a, oldLS, newLS);
- }
-
done:
if (do_trace) {
- char buf[200];
+ HChar buf[200];
VG_(printf)("RW-Locks held: ");
show_lockset(thr->locksetA);
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