Mirror/zeek
1
0
Fork 0
mirror of https://github.com/zeek/zeek.git synced 2025-10-12 03:28:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

initial elements of switching over CSE validity to full assessment of side effects

Browse source
This commit is contained in:
Vern Paxson 2023-11-28 15:01:52 -08:00
parent 8a18d5f8a2
commit eab33725f8
5 changed files with 186 additions and 28 deletions
Download patch file Download diff file Expand all files Collapse all files

118
src/script_opt/Reduce.cc
View file

@ -425,6 +425,32 @@ IDPtr Reducer::FindExprTmp(const Expr* rhs, const Expr* a, const std::shared_ptr
}
bool Reducer::ExprValid(const ID* id, const Expr* e1, const Expr* e2) const {
// First check for whether e1 is already known to itself have side effects.
// If so, then it's never safe to reuse its associated identifier in lieu
// of e2.
std::optional<ExprSideEffects>& e1_se = e1->GetOptInfo()->SideEffects();
if ( ! e1_se )
{
bool has_side_effects;
if ( e1->Tag() == EXPR_INDEX )
has_side_effects = pfs.GetSideEffects(SideEffectsOp::READ, e1->GetOp1()->GetType().get());
else if ( e1->Tag() == EXPR_RECORD_CONSTRUCTOR || e1->Tag() == EXPR_RECORD_COERCE )
has_side_effects = pfs.GetSideEffects(SideEffectsOp::CONSTRUCTION, e1->GetType().get());
else
has_side_effects = false;
e1_se = ExprSideEffects(has_side_effects);
}
if ( e1_se->HasSideEffects() )
{
// We already know that e2 is structurally identical to e1.
e2->GetOptInfo()->SideEffects() = ExprSideEffects(true);
return false;
}
// Here are the considerations for expression validity.
//
// * None of the operands used in the given expression can
@ -964,19 +990,27 @@ TraversalCode CSE_ValidityChecker::PreExpr(const Expr* e) {
break;
case EXPR_INDEX:
case EXPR_FIELD:
case EXPR_FIELD: {
// We treat these together because they both have to be checked
// when inside an "add" or "delete" statement.
auto aggr = e->GetOp1();
if ( in_aggr_mod_stmt ) {
auto aggr = e->GetOp1();
auto aggr_id = aggr->AsNameExpr()->Id();
if ( CheckID(aggr_id, true) ) {
if ( CheckID(aggr_id, true) || CheckAggrMod(e) ) {
is_valid = false;
return TC_ABORTALL;
}
}
else if ( t == EXPR_INDEX && aggr->GetType()->Tag() == TYPE_TABLE ) {
if ( CheckTableRef(e) ) {
is_valid = false;
return TC_ABORTALL;
}
}
#if 0
if ( t == EXPR_INDEX && have_sensitive_IDs ) {
// Unfortunately in isolation we can't statically determine
// whether this table has a &default associated with it.
@ -986,9 +1020,11 @@ TraversalCode CSE_ValidityChecker::PreExpr(const Expr* e) {
// lot of work for what might be minimal gain.
is_valid = false;
return TC_ABORTALL;
}
}
#endif
}
break;
break;
default: break;
}
@ -1009,9 +1045,7 @@ bool CSE_ValidityChecker::CheckID(const ID* id, bool ignore_orig) const {
if ( id_t && same_type(id_t, i->GetType()) ) {
// Same-type aggregate.
if ( ! ignore_orig )
printf("identifier %s (%d), start %s, end %s\n", id->Name(), ignore_orig, obj_desc(start_e).c_str(),
obj_desc(end_e).c_str());
// if ( ! ignore_orig ) printf("identifier %s (%d), start %s, end %s\n", id->Name(), ignore_orig, obj_desc(start_e).c_str(), obj_desc(end_e).c_str());
if ( ignore_orig )
return true;
}
@ -1023,10 +1057,72 @@ bool CSE_ValidityChecker::CheckID(const ID* id, bool ignore_orig) const {
bool CSE_ValidityChecker::CheckAggrMod(const Expr* e) const {
const auto& e_i_t = e->GetType();
if ( IsAggr(e_i_t) ) {
// This assignment sets an aggregate value. Look for type matches.
for ( auto i : ids )
if ( same_type(e_i_t, i->GetType()) )
// This assignment sets an aggregate value.
// Note, the following will almost always remain empty, so spinning
// through them in the loop below will be very quick.
IDSet non_local_ids;
std::unordered_set<const Type*> aggrs;
// Here we do a bit of speed optimization by wiring in knowledge
// the aggregate WRITE effects only occur for tables.
if ( e_i_t->Tag() == TYPE_TABLE && pfs.GetSideEffects(SideEffectsOp::WRITE, e_i_t.get(), non_local_ids, aggrs) )
return true;
for ( auto i : ids ) {
for ( auto nli : non_local_ids )
if ( nli == i ) {
// printf("non-local ID on WRITE: %s\n", i->Name());
return true;
}
auto i_t = i->GetType();
if ( i_t->Tag() == TYPE_ANY )
continue;
if ( same_type(e_i_t, i_t) )
return true;
for ( auto a : aggrs )
if ( same_type(a, i_t.get()) ) {
// printf("aggr type on WRITE: %s\n", i->Name());
return true;
}
}
}
return false;
}
bool CSE_ValidityChecker::CheckTableRef(const Expr* e) const {
const auto& e_i_t = e->GetType();
// This assignment sets an aggregate value.
// Note, the following will almost always remain empty, so spinning
// through them in the loop below will be very quick.
IDSet non_local_ids;
std::unordered_set<const Type*> aggrs;
if ( pfs.GetSideEffects(SideEffectsOp::READ, e_i_t.get(), non_local_ids, aggrs) )
return true;
for ( auto i : ids ) {
for ( auto nli : non_local_ids )
if ( nli == i ) {
// printf("non-local ID on READ: %s\n", i->Name());
return true;
}
auto i_t = i->GetType();
if ( i_t->Tag() == TYPE_ANY )
continue;
for ( auto a : aggrs )
if ( same_type(a, i->GetType().get()) ) {
// printf("aggr type on READ: %p %s\n", e, obj_desc(e).c_str());
return true;
}
}
return false;