mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-08-06 03:10:25 +00:00
Code Activity

Fix O(n²) performance issue in CLI datatype declaration processing (#7712)

Browse source 
* Initial plan

* Implement batch initialization fix for O(n²) datatype performance issue

Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>

* Fix the real O(n²) bottleneck with lazy hash table for constructor name lookups

Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>

* Optimize get_constructor_by_name: use func_decl* parameter, add linear search optimization for small datatypes, and ensure non-null postcondition

Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>
This commit is contained in:
Copilot 2025-07-02 09:54:36 -07:00 • committed by GitHub
parent 53c48f7226
commit 75678fc2c2
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
2 changed files with 39 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

27
src/ast/datatype_decl_plugin.cpp
View file

@ -1076,14 +1076,13 @@ namespace datatype {
sort * datatype = con->get_range();
def const& d = get_def(datatype);
for (constructor const* c : d) {
if (c->name() == con->get_name()) {
for (accessor const* a : *c) {
func_decl_ref fn = a->instantiate(datatype);
res->push_back(fn);
plugin().add_ast(fn);
}
break;
// Use O(1) lookup instead of O(n) linear search
constructor* c = d.get_constructor_by_name(con);
if (c) {
for (accessor const* a : *c) {
func_decl_ref fn = a->instantiate(datatype);
res->push_back(fn);
plugin().add_ast(fn);
}
}
return res;
@ -1105,13 +1104,11 @@ namespace datatype {
sort * datatype = con->get_range();
def const& dd = get_def(datatype);
symbol r;
// This should be fixed for perf.
// Option 1: hash-table in dd that maps to constructors instead of iterating over all constructors.
// initialize the hash-table lazily when dd is large.
// Option 2: initialize all calls to plugin() registration in a single pass.
for (constructor const* c : dd)
if (c->name() == con->get_name())
r = c->recognizer();
// Use O(1) lookup instead of O(n) linear search
constructor* c = dd.get_constructor_by_name(con);
if (c) {
r = c->recognizer();
}
parameter ps[2] = { parameter(con), parameter(r) };
d = m.mk_func_decl(fid(), OP_DT_RECOGNISER, 2, ps, 1, &datatype);
SASSERT(d);

27
src/ast/datatype_decl_plugin.h
View file

@ -26,6 +26,7 @@ Revision History:
#include "util/buffer.h"
#include "util/symbol_table.h"
#include "util/obj_hashtable.h"
#include "util/dictionary.h"
enum sort_kind {
@ -164,6 +165,7 @@ namespace datatype {
sort_ref_vector m_params;
mutable sort_ref m_sort;
ptr_vector<constructor> m_constructors;
mutable dictionary<constructor*> m_name2constructor;
public:
def(ast_manager& m, util& u, symbol const& n, unsigned class_id, unsigned num_params, sort * const* params):
m(m),
@ -195,6 +197,31 @@ namespace datatype {
util& u() const { return m_util; }
param_size::size* sort_size() { return m_sort_size; }
void set_sort_size(param_size::size* p) { auto* q = m_sort_size; m_sort_size = p; if (p) p->inc_ref(); if (q) q->dec_ref(); m_sort = nullptr; }
constructor* get_constructor_by_name(func_decl* con) const {
symbol const& name = con->get_name();
constructor* result = nullptr;
// For small datatypes (< 10 constructors), use linear search instead of hash table
if (m_constructors.size() < 10) {
for (constructor* c : m_constructors) {
if (c->name() == name) {
result = c;
break;
}
}
} else {
// Lazy initialization of name-to-constructor map for O(1) lookups
if (m_name2constructor.empty() && !m_constructors.empty()) {
for (constructor* c : m_constructors) {
m_name2constructor.insert(c->name(), c);
}
}
m_name2constructor.find(name, result);
}
SASSERT(result); // Post-condition: get_constructor_by_name returns a non-null result
return result;
}
def* translate(ast_translation& tr, util& u);
};