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Initial commit of Hyperscan
This commit is contained in:
Matthew Barr
667
src/rose/rose_build_lookaround.cpp
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667
src/rose/rose_build_lookaround.cpp
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@@ -0,0 +1,667 @@
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/*
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* Copyright (c) 2015, Intel Corporation
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Intel Corporation nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/** \file
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* \brief Rose compile-time analysis for lookaround masks.
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*/
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#include "rose_build_lookaround.h"
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#include "rose_build_impl.h"
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#include "nfa/castlecompile.h"
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#include "nfa/goughcompile.h"
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#include "nfa/rdfa.h"
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#include "nfagraph/ng_repeat.h"
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#include "nfagraph/ng_util.h"
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#include "util/container.h"
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#include "util/dump_charclass.h"
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#include "util/graph_range.h"
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#include "util/ue2_containers.h"
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#include "util/verify_types.h"
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#include <cstdlib>
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#include <queue>
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using namespace std;
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namespace ue2 {
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/** \brief Max search distance for reachability in front of a role. */
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static const u32 MAX_FWD_LEN = 64;
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/** \brief Max search distance for reachability behind a role. */
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static const u32 MAX_BACK_LEN = 64;
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/** \brief Max lookaround entries for a role. */
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static const u32 MAX_LOOKAROUND_ENTRIES = 16;
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/** \brief We would rather have lookarounds with smaller reach than this. */
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static const u32 LOOKAROUND_WIDE_REACH = 200;
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static
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void getForwardReach(const NGHolder &g, u32 top, map<s32, CharReach> &look) {
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ue2::flat_set<NFAVertex> curr, next;
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// Consider only successors of start with the required top.
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for (const auto &e : out_edges_range(g.start, g)) {
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NFAVertex v = target(e, g);
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if (v == g.startDs) {
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continue;
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}
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if (g[e].top == top) {
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curr.insert(v);
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}
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}
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for (u32 i = 0; i < MAX_FWD_LEN; i++) {
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if (curr.empty() || contains(curr, g.accept) ||
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contains(curr, g.acceptEod)) {
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break;
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}
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next.clear();
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CharReach cr;
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for (auto v : curr) {
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assert(!is_special(v, g));
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cr |= g[v].char_reach;
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insert(&next, adjacent_vertices(v, g));
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}
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assert(cr.any());
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look[i] |= cr;
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curr.swap(next);
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}
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}
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static
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void getBackwardReach(const NGHolder &g, ReportID report, u32 lag,
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map<s32, CharReach> &look) {
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ue2::flat_set<NFAVertex> curr, next;
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for (auto v : inv_adjacent_vertices_range(g.accept, g)) {
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if (contains(g[v].reports, report)) {
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curr.insert(v);
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}
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}
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for (u32 i = lag + 1; i <= MAX_BACK_LEN; i++) {
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if (curr.empty() || contains(curr, g.start) ||
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contains(curr, g.startDs)) {
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break;
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}
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next.clear();
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CharReach cr;
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for (auto v : curr) {
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assert(!is_special(v, g));
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cr |= g[v].char_reach;
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insert(&next, inv_adjacent_vertices(v, g));
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}
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assert(cr.any());
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look[0 - i] |= cr;
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curr.swap(next);
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}
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}
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static
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void getForwardReach(const CastleProto &castle, u32 top,
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map<s32, CharReach> &look) {
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depth len = castle.repeats.at(top).bounds.min;
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len = min(len, depth(MAX_FWD_LEN));
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assert(len.is_finite());
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const CharReach &cr = castle.reach();
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for (u32 i = 0; i < len; i++) {
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look[i] |= cr;
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}
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}
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static
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void getBackwardReach(const CastleProto &castle, ReportID report, u32 lag,
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map<s32, CharReach> &look) {
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depth min_depth = depth::infinity();
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for (const auto &m : castle.repeats) {
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const PureRepeat &pr = m.second;
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if (contains(pr.reports, report)) {
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min_depth = min(min_depth, pr.bounds.min);
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}
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}
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if (!min_depth.is_finite()) {
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assert(0);
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return;
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}
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const CharReach &cr = castle.reach();
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for (u32 i = lag + 1; i <= min(lag + (u32)min_depth, MAX_BACK_LEN);
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i++) {
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look[0 - i] |= cr;
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}
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}
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static
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void getForwardReach(const raw_dfa &rdfa, map<s32, CharReach> &look) {
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if (rdfa.states.size() < 2) {
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return;
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}
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ue2::flat_set<dstate_id_t> curr, next;
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curr.insert(rdfa.start_anchored);
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for (u32 i = 0; i < MAX_FWD_LEN && !curr.empty(); i++) {
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next.clear();
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CharReach cr;
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for (const auto state_id : curr) {
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const dstate &ds = rdfa.states[state_id];
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if (!ds.reports.empty() || !ds.reports_eod.empty()) {
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return;
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}
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for (unsigned c = 0; c < N_CHARS; c++) {
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dstate_id_t succ = ds.next[rdfa.alpha_remap[c]];
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if (succ != DEAD_STATE) {
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cr.set(c);
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next.insert(succ);
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}
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}
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}
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assert(cr.any());
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look[i] |= cr;
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curr.swap(next);
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}
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}
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static
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void getSuffixForwardReach(const suffix_id &suff, u32 top,
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map<s32, CharReach> &look) {
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if (suff.graph()) {
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getForwardReach(*suff.graph(), top, look);
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} else if (suff.castle()) {
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getForwardReach(*suff.castle(), top, look);
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} else if (suff.dfa()) {
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assert(top == 0); // DFA isn't multi-top capable.
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getForwardReach(*suff.dfa(), look);
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} else if (suff.haig()) {
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assert(top == 0); // DFA isn't multi-top capable.
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getForwardReach(*suff.haig(), look);
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}
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}
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static
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void getRoseForwardReach(const left_id &left, u32 top,
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map<s32, CharReach> &look) {
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if (left.graph()) {
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getForwardReach(*left.graph(), top, look);
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} else if (left.castle()) {
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getForwardReach(*left.castle(), top, look);
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} else if (left.dfa()) {
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assert(top == 0); // DFA isn't multi-top capable.
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getForwardReach(*left.dfa(), look);
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} else if (left.haig()) {
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assert(top == 0); // DFA isn't multi-top capable.
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getForwardReach(*left.haig(), look);
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}
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}
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static
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void combineForwardMasks(const vector<map<s32, CharReach> > &rose_look,
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map<s32, CharReach> &look) {
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for (u32 i = 0; i < MAX_FWD_LEN; i++) {
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for (const auto &rlook : rose_look) {
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if (contains(rlook, i)) {
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look[i] |= rlook.at(i);
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} else {
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look[i].setall();
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}
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}
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}
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}
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static
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void findForwardReach(const RoseGraph &g, const RoseVertex v,
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map<s32, CharReach> &look) {
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if (!g[v].reports.empty()) {
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DEBUG_PRINTF("acceptor\n");
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return;
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}
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// Non-leaf vertices can pick up a mask per successor prefix rose
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// engine.
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vector<map<s32, CharReach>> rose_look;
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for (const auto &e : out_edges_range(v, g)) {
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RoseVertex t = target(e, g);
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if (!g[t].left) {
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DEBUG_PRINTF("successor %zu has no leftfix\n", g[t].idx);
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return;
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}
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rose_look.push_back(map<s32, CharReach>());
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getRoseForwardReach(g[t].left, g[e].rose_top, rose_look.back());
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}
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if (g[v].suffix) {
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DEBUG_PRINTF("suffix engine\n");
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rose_look.push_back(map<s32, CharReach>());
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getSuffixForwardReach(g[v].suffix, g[v].suffix.top, rose_look.back());
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}
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combineForwardMasks(rose_look, look);
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}
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static
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void findBackwardReach(const RoseGraph &g, const RoseVertex v,
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map<s32, CharReach> &look) {
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if (!g[v].left) {
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return;
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}
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DEBUG_PRINTF("leftfix, report=%u, lag=%u\n", g[v].left.leftfix_report,
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g[v].left.lag);
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if (g[v].left.graph) {
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getBackwardReach(*g[v].left.graph, g[v].left.leftfix_report,
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g[v].left.lag, look);
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} else if (g[v].left.castle) {
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getBackwardReach(*g[v].left.castle, g[v].left.leftfix_report,
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g[v].left.lag, look);
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}
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// TODO: implement DFA variants if necessary.
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}
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#if defined(DEBUG) || defined(DUMP_SUPPORT)
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#include <sstream>
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static UNUSED
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string dump(const map<s32, CharReach> &look) {
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ostringstream oss;
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for (auto it = look.begin(), ite = look.end(); it != ite; ++it) {
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if (it != look.begin()) {
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oss << ", ";
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}
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oss << "{" << it->first << ": " << describeClass(it->second) << "}";
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}
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return oss.str();
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}
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#endif
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static
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void normalise(map<s32, CharReach> &look) {
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// We can erase entries where the reach is "all characters".
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vector<s32> dead;
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for (const auto &m : look) {
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if (m.second.all()) {
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dead.push_back(m.first);
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}
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}
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erase_all(&look, dead);
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}
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namespace {
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struct LookPriority {
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explicit LookPriority(const map<s32, CharReach> &look_in) : look(look_in) {}
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bool operator()(s32 a, s32 b) const {
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const CharReach &a_reach = look.at(a);
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const CharReach &b_reach = look.at(b);
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if (a_reach.count() != b_reach.count()) {
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return a_reach.count() < b_reach.count();
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}
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return abs(a) < abs(b);
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}
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private:
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const map<s32, CharReach> &look;
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};
|
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} // namespace
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static
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bool isFloodProne(const map<s32, CharReach> &look, const CharReach &flood_cr) {
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for (const auto &m : look) {
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const CharReach &look_cr = m.second;
|
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if (!overlaps(look_cr, flood_cr)) {
|
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return false;
|
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}
|
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}
|
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DEBUG_PRINTF("look can't escape flood on %s\n",
|
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describeClass(flood_cr).c_str());
|
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return true;
|
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}
|
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|
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static
|
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bool isFloodProne(const map<s32, CharReach> &look,
|
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const set<CharReach> &flood_reach) {
|
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if (flood_reach.empty()) {
|
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return false;
|
||||
}
|
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|
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for (const CharReach &flood_cr : flood_reach) {
|
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if (isFloodProne(look, flood_cr)) {
|
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return true;
|
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}
|
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}
|
||||
|
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return false;
|
||||
}
|
||||
|
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static
|
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void reduce(map<s32, CharReach> &look, set<CharReach> &flood_reach) {
|
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if (look.size() <= MAX_LOOKAROUND_ENTRIES) {
|
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return;
|
||||
}
|
||||
|
||||
DEBUG_PRINTF("before reduce: %s\n", dump(look).c_str());
|
||||
|
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// First, remove floods that we already can't escape; they shouldn't affect
|
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// the analysis below.
|
||||
for (auto it = flood_reach.begin(); it != flood_reach.end();) {
|
||||
if (isFloodProne(look, *it)) {
|
||||
DEBUG_PRINTF("removing inescapable flood on %s from analysis\n",
|
||||
describeClass(*it).c_str());
|
||||
flood_reach.erase(it++);
|
||||
} else {
|
||||
++it;
|
||||
}
|
||||
}
|
||||
|
||||
LookPriority cmp(look);
|
||||
priority_queue<s32, vector<s32>, LookPriority> pq(cmp);
|
||||
for (const auto &m : look) {
|
||||
pq.push(m.first);
|
||||
}
|
||||
|
||||
while (!pq.empty() && look.size() > MAX_LOOKAROUND_ENTRIES) {
|
||||
s32 d = pq.top();
|
||||
assert(contains(look, d));
|
||||
const CharReach cr(look[d]); // copy
|
||||
pq.pop();
|
||||
|
||||
DEBUG_PRINTF("erasing {%d: %s}\n", d, describeClass(cr).c_str());
|
||||
look.erase(d);
|
||||
|
||||
// If removing this entry would result in us becoming flood_prone on a
|
||||
// particular flood_reach case, reinstate it and move on.
|
||||
if (isFloodProne(look, flood_reach)) {
|
||||
DEBUG_PRINTF("reinstating {%d: %s} due to flood-prone check\n", d,
|
||||
describeClass(cr).c_str());
|
||||
look.insert(make_pair(d, cr));
|
||||
}
|
||||
}
|
||||
|
||||
while (!pq.empty()) {
|
||||
s32 d = pq.top();
|
||||
assert(contains(look, d));
|
||||
const CharReach cr(look[d]); // copy
|
||||
pq.pop();
|
||||
|
||||
if (cr.count() < LOOKAROUND_WIDE_REACH) {
|
||||
continue;
|
||||
}
|
||||
|
||||
DEBUG_PRINTF("erasing {%d: %s}\n", d, describeClass(cr).c_str());
|
||||
look.erase(d);
|
||||
|
||||
// If removing this entry would result in us becoming flood_prone on a
|
||||
// particular flood_reach case, reinstate it and move on.
|
||||
if (isFloodProne(look, flood_reach)) {
|
||||
DEBUG_PRINTF("reinstating {%d: %s} due to flood-prone check\n", d,
|
||||
describeClass(cr).c_str());
|
||||
look.insert(make_pair(d, cr));
|
||||
}
|
||||
}
|
||||
|
||||
DEBUG_PRINTF("after reduce: %s\n", dump(look).c_str());
|
||||
}
|
||||
|
||||
static
|
||||
void findFloodReach(const RoseBuildImpl &tbi, const RoseVertex v,
|
||||
set<CharReach> &flood_reach) {
|
||||
for (u32 lit_id : tbi.g[v].literals) {
|
||||
const ue2_literal &s = tbi.literals.right.at(lit_id).s;
|
||||
if (s.empty()) {
|
||||
continue;
|
||||
}
|
||||
if (is_flood(s)) {
|
||||
CharReach cr(*s.begin());
|
||||
DEBUG_PRINTF("flood-prone with reach: %s\n",
|
||||
describeClass(cr).c_str());
|
||||
flood_reach.insert(cr);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
static
|
||||
map<s32, CharReach> findLiteralReach(const RoseBuildImpl &build,
|
||||
const RoseVertex v) {
|
||||
map<s32, CharReach> look;
|
||||
for (u32 lit_id : build.g[v].literals) {
|
||||
const rose_literal_id &lit = build.literals.right.at(lit_id);
|
||||
|
||||
u32 i = lit.delay + 1;
|
||||
for (auto it = lit.s.rbegin(), ite = lit.s.rend(); it != ite; ++it) {
|
||||
look[0 - i] |= *it;
|
||||
i++;
|
||||
}
|
||||
}
|
||||
|
||||
DEBUG_PRINTF("lit lookaround: %s\n", dump(look).c_str());
|
||||
return look;
|
||||
}
|
||||
|
||||
/**
|
||||
* Trim lookaround checks from the prefix that overlap with the literals
|
||||
* themselves.
|
||||
*/
|
||||
static
|
||||
void trimLiterals(const RoseBuildImpl &build, const RoseVertex v,
|
||||
map<s32, CharReach> &look) {
|
||||
DEBUG_PRINTF("pre-trim lookaround: %s\n", dump(look).c_str());
|
||||
|
||||
for (const auto &m : findLiteralReach(build, v)) {
|
||||
auto it = look.find(m.first);
|
||||
if (it == end(look)) {
|
||||
continue;
|
||||
}
|
||||
if (m.second.isSubsetOf(it->second)) {
|
||||
DEBUG_PRINTF("can trim entry at %d\n", it->first);
|
||||
look.erase(it);
|
||||
}
|
||||
}
|
||||
|
||||
DEBUG_PRINTF("post-trim lookaround: %s\n", dump(look).c_str());
|
||||
}
|
||||
|
||||
void findLookaroundMasks(const RoseBuildImpl &tbi, const RoseVertex v,
|
||||
vector<LookEntry> &lookaround) {
|
||||
lookaround.clear();
|
||||
|
||||
const RoseGraph &g = tbi.g;
|
||||
|
||||
map<s32, CharReach> look;
|
||||
findBackwardReach(g, v, look);
|
||||
findForwardReach(g, v, look);
|
||||
trimLiterals(tbi, v, look);
|
||||
|
||||
if (look.empty()) {
|
||||
return;
|
||||
}
|
||||
|
||||
normalise(look);
|
||||
|
||||
if (look.empty()) {
|
||||
return;
|
||||
}
|
||||
|
||||
set<CharReach> flood_reach;
|
||||
findFloodReach(tbi, v, flood_reach);
|
||||
reduce(look, flood_reach);
|
||||
|
||||
if (look.empty()) {
|
||||
return;
|
||||
}
|
||||
|
||||
DEBUG_PRINTF("lookaround: %s\n", dump(look).c_str());
|
||||
lookaround.reserve(look.size());
|
||||
for (const auto &m : look) {
|
||||
s8 offset = verify_s8(m.first);
|
||||
lookaround.emplace_back(offset, m.second);
|
||||
}
|
||||
}
|
||||
|
||||
static
|
||||
bool getTransientPrefixReach(const NGHolder &g, u32 lag,
|
||||
map<s32, CharReach> &look) {
|
||||
if (in_degree(g.accept, g) != 1) {
|
||||
DEBUG_PRINTF("more than one accept\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
// Currently we don't handle anchored prefixes, as we would need to be able
|
||||
// to represent the bounds from the anchor as well.
|
||||
if (out_degree(g.start, g) != 1) {
|
||||
DEBUG_PRINTF("anchored\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
if (out_degree(g.startDs, g) != 2) {
|
||||
DEBUG_PRINTF("more than one start\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
NFAVertex v = *(inv_adjacent_vertices(g.accept, g).first);
|
||||
u32 i = lag + 1;
|
||||
while (v != g.startDs) {
|
||||
DEBUG_PRINTF("i=%u, v=%u\n", i, g[v].index);
|
||||
if (is_special(v, g)) {
|
||||
DEBUG_PRINTF("special\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
look[0 - i] = g[v].char_reach;
|
||||
|
||||
if (in_degree(v, g) != 1) {
|
||||
DEBUG_PRINTF("branch\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
v = *(inv_adjacent_vertices(v, g).first);
|
||||
i++;
|
||||
}
|
||||
|
||||
DEBUG_PRINTF("done\n");
|
||||
return true;
|
||||
}
|
||||
|
||||
bool makeLeftfixLookaround(const RoseBuildImpl &build, const RoseVertex v,
|
||||
vector<LookEntry> &lookaround) {
|
||||
lookaround.clear();
|
||||
|
||||
const RoseGraph &g = build.g;
|
||||
const left_id leftfix(g[v].left);
|
||||
|
||||
if (!contains(build.transient, leftfix)) {
|
||||
DEBUG_PRINTF("not transient\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
if (!leftfix.graph()) {
|
||||
DEBUG_PRINTF("only supported for graphs so far\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
map<s32, CharReach> look;
|
||||
if (!getTransientPrefixReach(*leftfix.graph(), g[v].left.lag, look)) {
|
||||
DEBUG_PRINTF("not a chain\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
trimLiterals(build, v, look);
|
||||
|
||||
if (look.size() > MAX_LOOKAROUND_ENTRIES) {
|
||||
DEBUG_PRINTF("lookaround too big (%zu entries)\n", look.size());
|
||||
return false;
|
||||
}
|
||||
|
||||
if (look.empty()) {
|
||||
DEBUG_PRINTF("lookaround empty; this is weird\n");
|
||||
return false;
|
||||
}
|
||||
|
||||
lookaround.reserve(look.size());
|
||||
for (const auto &m : look) {
|
||||
s8 offset = verify_s8(m.first);
|
||||
lookaround.emplace_back(offset, m.second);
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
void mergeLookaround(vector<LookEntry> &lookaround,
|
||||
const vector<LookEntry> &more_lookaround) {
|
||||
if (lookaround.size() >= MAX_LOOKAROUND_ENTRIES) {
|
||||
DEBUG_PRINTF("big enough!\n");
|
||||
return;
|
||||
}
|
||||
|
||||
// Don't merge lookarounds at offsets we already have entries for.
|
||||
ue2::flat_set<s8> offsets;
|
||||
for (const auto &e : lookaround) {
|
||||
offsets.insert(e.offset);
|
||||
}
|
||||
|
||||
map<s32, CharReach> more;
|
||||
LookPriority cmp(more);
|
||||
priority_queue<s32, vector<s32>, LookPriority> pq(cmp);
|
||||
for (const auto &e : more_lookaround) {
|
||||
if (!contains(offsets, e.offset)) {
|
||||
more.emplace(e.offset, e.reach);
|
||||
pq.push(e.offset);
|
||||
}
|
||||
}
|
||||
|
||||
while (!pq.empty() && lookaround.size() < MAX_LOOKAROUND_ENTRIES) {
|
||||
const s32 offset = pq.top();
|
||||
pq.pop();
|
||||
const auto &cr = more.at(offset);
|
||||
DEBUG_PRINTF("added {%d,%s}\n", offset, describeClass(cr).c_str());
|
||||
lookaround.emplace_back(verify_s8(offset), cr);
|
||||
}
|
||||
|
||||
// Order by offset.
|
||||
sort(begin(lookaround), end(lookaround),
|
||||
[](const LookEntry &a, const LookEntry &b) {
|
||||
return a.offset < b.offset;
|
||||
});
|
||||
}
|
||||
|
||||
} // namespace ue2
|
||||
Reference in New Issue
Block a user