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Bias storage of events towards static scopes. 

This patch modifies the code that finds and combines similar events
such that if similar events are found in both static and automatic
scopes, the retained event will be in a static scope. This is a
performance enhancement, as VVP has more run-time overhead when
handling events declared in an automatic scope.
This commit is contained in:
Martin Whitaker 2008-10-12 20:11:31 +01:00 committed by Stephen Williams
parent c41fb50929
commit 647b3e5bda
1 changed files with 82 additions and 55 deletions
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137
nodangle.cc
View File

@ -37,14 +37,18 @@ class nodangle_f : public functor_t {
void event(Design*des, NetEvent*ev);
void signal(Design*des, NetNet*sig);
unsigned count_;
unsigned iteration;
unsigned stotal, etotal;
bool scontinue, econtinue;
bool scomplete, ecomplete;
};
void nodangle_f::event(Design*des, NetEvent*ev)
{
if (ecomplete) return;
/* If there are no references to this event, then go right
ahead and delete in. There is no use looking further at
ahead and delete it. There is no use looking further at
it. */
if ((ev->nwait() + ev->ntrig() + ev->nexpr()) == 0) {
delete ev;
@ -52,58 +56,79 @@ void nodangle_f::event(Design*des, NetEvent*ev)
return;
}
/* Try to remove duplicate probes from the event. */
for (unsigned idx = 0 ; idx < ev->nprobe() ; idx += 1) {
unsigned jdx = idx + 1;
while (jdx < ev->nprobe()) {
NetEvProbe*ip = ev->probe(idx);
NetEvProbe*jp = ev->probe(jdx);
if (iteration == 0) {
/* Try to remove duplicate probes from the event. This
is done as a separate initial pass to ensure similar
events are detected as soon as possible in subsequent
iterations. */
for (unsigned idx = 0 ; idx < ev->nprobe() ; idx += 1) {
unsigned jdx = idx + 1;
while (jdx < ev->nprobe()) {
NetEvProbe*ip = ev->probe(idx);
NetEvProbe*jp = ev->probe(jdx);
if (ip->edge() != jp->edge()) {
jdx += 1;
continue;
}
if (ip->edge() != jp->edge()) {
jdx += 1;
continue;
}
bool fully_connected = true;
for (unsigned jpin = 0; jpin < jp->pin_count(); jpin += 1) {
unsigned ipin = 0;
bool connected_flag = false;
for (ipin = 0 ; ipin < ip->pin_count(); ipin += 1)
if (connected(ip->pin(ipin), jp->pin(jpin))) {
connected_flag = true;
break;
}
bool fully_connected = true;
for (unsigned jpin = 0; jpin < jp->pin_count(); jpin += 1) {
unsigned ipin = 0;
bool connected_flag = false;
for (ipin = 0 ; ipin < ip->pin_count(); ipin += 1)
if (connected(ip->pin(ipin), jp->pin(jpin))) {
connected_flag = true;
break;
}
if (!connected_flag) {
fully_connected = false;
break;
}
}
if (!connected_flag) {
fully_connected = false;
break;
}
}
if (fully_connected) {
delete jp;
} else {
jdx += 1;
}
}
if (fully_connected) {
delete jp;
} else {
jdx += 1;
}
}
}
econtinue = true;
} else {
/* Postpone examining events in an automatic scope until the
third (optional) pass. This will mean similar events are
biased towards being stored in static scopes. */
if (ev->scope()->is_auto()) {
if (iteration == 1) {
econtinue = true;
return;
}
} else {
if (iteration == 2) {
return;
}
}
/* Try to find all the events that are similar to me, and
replace their references with references to me. */
list<NetEvent*> match;
ev->find_similar_event(match);
for (list<NetEvent*>::iterator idx = match.begin()
; idx != match.end() ; idx ++) {
NetEvent*tmp = *idx;
assert(tmp != ev);
tmp ->replace_event(ev);
}
}
/* Try to find all the events that are similar to me, and
replace their references with references to me. */
list<NetEvent*> match;
ev->find_similar_event(match);
for (list<NetEvent*>::iterator idx = match.begin()
; idx != match.end() ; idx ++) {
NetEvent*tmp = *idx;
assert(tmp != ev);
tmp ->replace_event(ev);
}
}
void nodangle_f::signal(Design*des, NetNet*sig)
{
if (scomplete) return;
/* Cannot delete signals referenced in an expression
or an l-value. */
if (sig->get_refs() > 0)
@ -174,7 +199,7 @@ void nodangle_f::signal(Design*des, NetNet*sig)
/* If every pin is connected to another significant signal,
then I can delete this one. */
if (significant_flags == sig->pin_count()) {
count_ += 1;
scontinue = true;
delete sig;
stotal += 1;
}
@ -183,23 +208,26 @@ void nodangle_f::signal(Design*des, NetNet*sig)
void nodangle(Design*des)
{
nodangle_f fun;
unsigned count_iterations = 0;
fun.iteration = 0;
fun.stotal = 0;
fun.etotal = 0;
fun.scomplete = false;
fun.ecomplete = false;
do {
fun.count_ = 0;
fun.scontinue = false;
fun.econtinue = false;
des->functor(&fun);
count_iterations += 1;
fun.iteration += 1;
fun.scomplete = !fun.scontinue;
fun.ecomplete = !fun.econtinue;
if (verbose_flag) {
cout << " ... " << count_iterations << " iterations"
cout << " ... " << fun.iteration << " iterations"
<< " deleted " << fun.stotal << " dangling signals"
<< " and " << fun.etotal << " events."
<< " (count=" << fun.count_ << ")" << endl;
<< " and " << fun.etotal << " events." << endl;
}
} while (fun.count_ > 0);
} while (fun.scontinue || fun.econtinue);
}
@ -285,4 +313,3 @@ void nodangle(Design*des)
* symbols generated by elaboration and other steps.
*
*/