mirror of
https://github.com/VectorCamp/vectorscan.git
synced 2025-06-28 16:41:01 +03:00
883 lines
25 KiB
C++
883 lines
25 KiB
C++
/*
|
|
* Copyright (c) 2015-2020, Intel Corporation
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions are met:
|
|
*
|
|
* * Redistributions of source code must retain the above copyright notice,
|
|
* this list of conditions and the following disclaimer.
|
|
* * Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* * Neither the name of Intel Corporation nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
|
|
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
/** \file
|
|
* \brief Rose compile-time analysis for lookaround masks.
|
|
*/
|
|
#include "rose_build_lookaround.h"
|
|
|
|
#include "rose_build_impl.h"
|
|
#include "nfa/castlecompile.h"
|
|
#include "nfa/goughcompile.h"
|
|
#include "nfa/rdfa.h"
|
|
#include "nfagraph/ng_repeat.h"
|
|
#include "nfagraph/ng_util.h"
|
|
#include "util/container.h"
|
|
#include "util/dump_charclass.h"
|
|
#include "util/graph_range.h"
|
|
#include "util/flat_containers.h"
|
|
#include "util/verify_types.h"
|
|
|
|
#include <cstdlib>
|
|
#include <queue>
|
|
#include <sstream>
|
|
|
|
using namespace std;
|
|
|
|
namespace ue2 {
|
|
|
|
/** \brief Max search distance for reachability in front of a role. */
|
|
static const u32 MAX_FWD_LEN = 64;
|
|
|
|
/** \brief Max search distance for reachability behind a role. */
|
|
static const u32 MAX_BACK_LEN = 64;
|
|
|
|
/** \brief Max lookaround entries for a role. */
|
|
static const u32 MAX_LOOKAROUND_ENTRIES = 32;
|
|
|
|
/** \brief We would rather have lookarounds with smaller reach than this. */
|
|
static const u32 LOOKAROUND_WIDE_REACH = 200;
|
|
|
|
#if defined(DEBUG) || defined(DUMP_SUPPORT)
|
|
static UNUSED
|
|
string dump(const map<s32, CharReach> &look) {
|
|
ostringstream oss;
|
|
for (auto it = look.begin(), ite = look.end(); it != ite; ++it) {
|
|
if (it != look.begin()) {
|
|
oss << ", ";
|
|
}
|
|
oss << "{" << it->first << ": " << describeClass(it->second) << "}";
|
|
}
|
|
return oss.str();
|
|
}
|
|
#endif
|
|
|
|
static
|
|
void getForwardReach(const NGHolder &g, u32 top, map<s32, CharReach> &look) {
|
|
flat_set<NFAVertex> curr, next;
|
|
|
|
// Consider only successors of start with the required top.
|
|
for (const auto &e : out_edges_range(g.start, g)) {
|
|
NFAVertex v = target(e, g);
|
|
if (v == g.startDs) {
|
|
continue;
|
|
}
|
|
if (contains(g[e].tops, top)) {
|
|
curr.insert(v);
|
|
}
|
|
}
|
|
|
|
for (u32 i = 0; i < MAX_FWD_LEN; i++) {
|
|
if (curr.empty() || contains(curr, g.accept) ||
|
|
contains(curr, g.acceptEod)) {
|
|
break;
|
|
}
|
|
|
|
next.clear();
|
|
CharReach cr;
|
|
|
|
for (auto v : curr) {
|
|
assert(!is_special(v, g));
|
|
cr |= g[v].char_reach;
|
|
insert(&next, adjacent_vertices(v, g));
|
|
}
|
|
|
|
assert(cr.any());
|
|
look[i] |= cr;
|
|
curr.swap(next);
|
|
}
|
|
}
|
|
|
|
static
|
|
void getBackwardReach(const NGHolder &g, ReportID report, u32 lag,
|
|
map<s32, CharReach> &look) {
|
|
flat_set<NFAVertex> curr, next;
|
|
|
|
for (auto v : inv_adjacent_vertices_range(g.accept, g)) {
|
|
if (contains(g[v].reports, report)) {
|
|
curr.insert(v);
|
|
}
|
|
}
|
|
|
|
for (u32 i = lag + 1; i <= MAX_BACK_LEN; i++) {
|
|
if (curr.empty() || contains(curr, g.start) ||
|
|
contains(curr, g.startDs)) {
|
|
break;
|
|
}
|
|
|
|
next.clear();
|
|
CharReach cr;
|
|
|
|
for (auto v : curr) {
|
|
assert(!is_special(v, g));
|
|
cr |= g[v].char_reach;
|
|
insert(&next, inv_adjacent_vertices(v, g));
|
|
}
|
|
|
|
assert(cr.any());
|
|
look[0 - i] |= cr;
|
|
curr.swap(next);
|
|
}
|
|
}
|
|
|
|
static
|
|
void getForwardReach(const CastleProto &castle, u32 top,
|
|
map<s32, CharReach> &look) {
|
|
depth len = castle.repeats.at(top).bounds.min;
|
|
len = min(len, depth(MAX_FWD_LEN));
|
|
assert(len.is_finite());
|
|
|
|
const CharReach &cr = castle.reach();
|
|
for (u32 i = 0; i < len; i++) {
|
|
look[i] |= cr;
|
|
}
|
|
}
|
|
|
|
static
|
|
void getBackwardReach(const CastleProto &castle, ReportID report, u32 lag,
|
|
map<s32, CharReach> &look) {
|
|
depth min_depth = depth::infinity();
|
|
for (const auto &m : castle.repeats) {
|
|
const PureRepeat &pr = m.second;
|
|
if (contains(pr.reports, report)) {
|
|
min_depth = min(min_depth, pr.bounds.min);
|
|
}
|
|
}
|
|
|
|
if (!min_depth.is_finite()) {
|
|
assert(0);
|
|
return;
|
|
}
|
|
|
|
const CharReach &cr = castle.reach();
|
|
for (u32 i = lag + 1; i <= min(lag + (u32)min_depth, MAX_BACK_LEN);
|
|
i++) {
|
|
look[0 - i] |= cr;
|
|
}
|
|
}
|
|
|
|
static
|
|
void getForwardReach(const raw_dfa &rdfa, map<s32, CharReach> &look) {
|
|
if (rdfa.states.size() < 2) {
|
|
return;
|
|
}
|
|
|
|
flat_set<dstate_id_t> curr, next;
|
|
curr.insert(rdfa.start_anchored);
|
|
|
|
for (u32 i = 0; i < MAX_FWD_LEN && !curr.empty(); i++) {
|
|
next.clear();
|
|
CharReach cr;
|
|
|
|
for (const auto state_id : curr) {
|
|
const dstate &ds = rdfa.states[state_id];
|
|
|
|
if (!ds.reports.empty() || !ds.reports_eod.empty()) {
|
|
return;
|
|
}
|
|
|
|
for (unsigned c = 0; c < N_CHARS; c++) {
|
|
dstate_id_t dnsucc = ds.next[rdfa.alpha_remap[c]];
|
|
if (dnsucc != DEAD_STATE) {
|
|
cr.set(c);
|
|
next.insert(dnsucc);
|
|
}
|
|
}
|
|
}
|
|
|
|
assert(cr.any());
|
|
look[i] |= cr;
|
|
curr.swap(next);
|
|
}
|
|
}
|
|
|
|
static
|
|
void getSuffixForwardReach(const suffix_id &suff, u32 top,
|
|
map<s32, CharReach> &look) {
|
|
if (suff.graph()) {
|
|
getForwardReach(*suff.graph(), top, look);
|
|
} else if (suff.castle()) {
|
|
getForwardReach(*suff.castle(), top, look);
|
|
} else if (suff.dfa()) {
|
|
assert(top == 0); // DFA isn't multi-top capable.
|
|
getForwardReach(*suff.dfa(), look);
|
|
} else if (suff.haig()) {
|
|
assert(top == 0); // DFA isn't multi-top capable.
|
|
getForwardReach(*suff.haig(), look);
|
|
}
|
|
}
|
|
|
|
static
|
|
void getRoseForwardReach(const left_id &left, u32 top,
|
|
map<s32, CharReach> &look) {
|
|
if (left.graph()) {
|
|
getForwardReach(*left.graph(), top, look);
|
|
} else if (left.castle()) {
|
|
getForwardReach(*left.castle(), top, look);
|
|
} else if (left.dfa()) {
|
|
assert(top == 0); // DFA isn't multi-top capable.
|
|
getForwardReach(*left.dfa(), look);
|
|
} else if (left.haig()) {
|
|
assert(top == 0); // DFA isn't multi-top capable.
|
|
getForwardReach(*left.haig(), look);
|
|
}
|
|
}
|
|
|
|
static
|
|
void combineForwardMasks(const vector<map<s32, CharReach> > &rose_look,
|
|
map<s32, CharReach> &look) {
|
|
for (u32 i = 0; i < MAX_FWD_LEN; i++) {
|
|
for (const auto &rlook : rose_look) {
|
|
if (contains(rlook, i)) {
|
|
look[i] |= rlook.at(i);
|
|
} else {
|
|
look[i].setall();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static
|
|
void findForwardReach(const RoseGraph &g, const RoseVertex v,
|
|
map<s32, CharReach> &look) {
|
|
if (!g[v].reports.empty()) {
|
|
DEBUG_PRINTF("acceptor\n");
|
|
return;
|
|
}
|
|
|
|
// Non-leaf vertices can pick up a mask per successor prefix rose
|
|
// engine.
|
|
vector<map<s32, CharReach>> rose_look;
|
|
for (const auto &e : out_edges_range(v, g)) {
|
|
RoseVertex t = target(e, g);
|
|
if (!g[t].left) {
|
|
DEBUG_PRINTF("successor %zu has no leftfix\n", g[t].index);
|
|
return;
|
|
}
|
|
rose_look.emplace_back(map<s32, CharReach>());
|
|
getRoseForwardReach(left_id(g[t].left), g[e].rose_top, rose_look.back());
|
|
}
|
|
|
|
if (g[v].suffix) {
|
|
DEBUG_PRINTF("suffix engine\n");
|
|
rose_look.emplace_back(map<s32, CharReach>());
|
|
getSuffixForwardReach(suffix_id(g[v].suffix), g[v].suffix.top, rose_look.back());
|
|
}
|
|
|
|
combineForwardMasks(rose_look, look);
|
|
}
|
|
|
|
static
|
|
void findBackwardReach(const RoseGraph &g, const RoseVertex v,
|
|
map<s32, CharReach> &look) {
|
|
if (!g[v].left) {
|
|
return;
|
|
}
|
|
|
|
DEBUG_PRINTF("leftfix, report=%u, lag=%u\n", g[v].left.leftfix_report,
|
|
g[v].left.lag);
|
|
|
|
if (g[v].left.graph) {
|
|
getBackwardReach(*g[v].left.graph, g[v].left.leftfix_report,
|
|
g[v].left.lag, look);
|
|
} else if (g[v].left.castle) {
|
|
getBackwardReach(*g[v].left.castle, g[v].left.leftfix_report,
|
|
g[v].left.lag, look);
|
|
}
|
|
|
|
// TODO: implement DFA variants if necessary.
|
|
}
|
|
|
|
static
|
|
void normalise(map<s32, CharReach> &look) {
|
|
// We can erase entries where the reach is "all characters".
|
|
vector<s32> dead;
|
|
for (const auto &m : look) {
|
|
if (m.second.all()) {
|
|
dead.emplace_back(m.first);
|
|
}
|
|
}
|
|
erase_all(&look, dead);
|
|
}
|
|
|
|
namespace {
|
|
|
|
struct LookPriority {
|
|
explicit LookPriority(const map<s32, CharReach> &look_in) : look(look_in) {}
|
|
|
|
bool operator()(s32 a, s32 b) const {
|
|
const CharReach &a_reach = look.at(a);
|
|
const CharReach &b_reach = look.at(b);
|
|
if (a_reach.count() != b_reach.count()) {
|
|
return a_reach.count() < b_reach.count();
|
|
}
|
|
return abs(a) < abs(b);
|
|
}
|
|
|
|
private:
|
|
const map<s32, CharReach> &look;
|
|
};
|
|
|
|
} // namespace
|
|
|
|
static
|
|
bool isFloodProne(const map<s32, CharReach> &look, const CharReach &flood_cr) {
|
|
// cppcheck-suppress useStlAlgorithm
|
|
for (const auto &m : look) {
|
|
const CharReach &look_cr = m.second;
|
|
if (!overlaps(look_cr, flood_cr)) {
|
|
return false;
|
|
}
|
|
}
|
|
DEBUG_PRINTF("look can't escape flood on %s\n",
|
|
describeClass(flood_cr).c_str());
|
|
return true;
|
|
}
|
|
|
|
static
|
|
bool isFloodProne(const map<s32, CharReach> &look,
|
|
const set<CharReach> &flood_reach) {
|
|
if (flood_reach.empty()) {
|
|
return false;
|
|
}
|
|
|
|
// cppcheck-suppress useStlAlgorithm
|
|
for (const CharReach &flood_cr : flood_reach) {
|
|
if (isFloodProne(look, flood_cr)) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static
|
|
void reduce(map<s32, CharReach> &look, set<CharReach> &flood_reach) {
|
|
if (look.size() <= MAX_LOOKAROUND_ENTRIES) {
|
|
return;
|
|
}
|
|
|
|
DEBUG_PRINTF("before reduce: %s\n", dump(look).c_str());
|
|
|
|
// First, remove floods that we already can't escape; they shouldn't affect
|
|
// 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.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);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
namespace {
|
|
struct LookProto {
|
|
LookProto(s32 offset_in, CharReach reach_in)
|
|
: offset(offset_in), reach(std::move(reach_in)) {}
|
|
s32 offset;
|
|
CharReach reach;
|
|
};
|
|
}
|
|
|
|
static
|
|
vector<LookProto> findLiteralReach(const rose_literal_id &lit) {
|
|
vector<LookProto> look;
|
|
look.reserve(lit.s.length());
|
|
|
|
s32 i = 0 - lit.s.length() - lit.delay;
|
|
for (const auto &c : lit.s) {
|
|
look.emplace_back(i, c);
|
|
i++;
|
|
}
|
|
|
|
return look;
|
|
}
|
|
|
|
static
|
|
vector<LookProto> findLiteralReach(const RoseBuildImpl &build,
|
|
const RoseVertex v) {
|
|
bool first = true;
|
|
vector<LookProto> look;
|
|
|
|
for (u32 lit_id : build.g[v].literals) {
|
|
const rose_literal_id &lit = build.literals.at(lit_id);
|
|
auto lit_look = findLiteralReach(lit);
|
|
|
|
if (first) {
|
|
look = std::move(lit_look);
|
|
first = false;
|
|
continue;
|
|
}
|
|
|
|
// Erase elements from look with keys not in lit_look. Where a key is
|
|
// in both maps, union its reach with the lookaround.
|
|
auto jt = begin(lit_look);
|
|
for (auto it = begin(look); it != end(look);) {
|
|
if (jt == end(lit_look)) {
|
|
// No further lit_look entries, erase remaining elements from
|
|
// look.
|
|
look.erase(it, end(look));
|
|
break;
|
|
}
|
|
if (it->offset < jt->offset) {
|
|
// Offset is present in look but not in lit_look, erase.
|
|
it = look.erase(it);
|
|
} else if (it->offset > jt->offset) {
|
|
// Offset is preset in lit_look but not in look, ignore.
|
|
++jt;
|
|
} else {
|
|
// Offset is present in both, union its reach with look.
|
|
it->reach |= jt->reach;
|
|
++it;
|
|
++jt;
|
|
}
|
|
}
|
|
}
|
|
|
|
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.offset);
|
|
if (it == end(look)) {
|
|
continue;
|
|
}
|
|
if (m.reach.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());
|
|
}
|
|
|
|
static
|
|
void normaliseLeftfix(map<s32, CharReach> &look) {
|
|
// We can erase entries where the reach is "all characters", except for the
|
|
// very first one -- this might be required to establish a minimum bound on
|
|
// the literal's match offset.
|
|
|
|
// TODO: It would be cleaner to use a literal program instruction to check
|
|
// the minimum bound explicitly.
|
|
|
|
if (look.empty()) {
|
|
return;
|
|
}
|
|
|
|
const auto earliest = begin(look)->first;
|
|
|
|
vector<s32> dead;
|
|
for (const auto &m : look) {
|
|
if (m.second.all() && m.first != earliest) {
|
|
dead.emplace_back(m.first);
|
|
}
|
|
}
|
|
erase_all(&look, dead);
|
|
}
|
|
|
|
static
|
|
bool trimMultipathLeftfix(const RoseBuildImpl &build, const RoseVertex v,
|
|
vector<map<s32, CharReach>> &looks) {
|
|
size_t path_count = 0;
|
|
for (auto &look : looks) {
|
|
++path_count;
|
|
DEBUG_PRINTF("Path #%ld\n", path_count);
|
|
|
|
assert(!look.empty());
|
|
trimLiterals(build, v, look);
|
|
|
|
if (look.empty()) {
|
|
return false;
|
|
}
|
|
|
|
// Could be optimized here, just keep the empty byte of the longest path
|
|
normaliseLeftfix(look);
|
|
|
|
if (look.size() > MAX_LOOKAROUND_ENTRIES) {
|
|
DEBUG_PRINTF("lookaround too big (%zu entries)\n", look.size());
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static
|
|
void transToLookaround(const vector<map<s32, CharReach>> &looks,
|
|
vector<vector<LookEntry>> &lookarounds) {
|
|
for (const auto &look : looks) {
|
|
vector<LookEntry> lookaround;
|
|
DEBUG_PRINTF("lookaround: %s\n", dump(look).c_str());
|
|
lookaround.reserve(look.size());
|
|
for (const auto &m : look) {
|
|
if (m.first < -128 || m.first > 127) {
|
|
DEBUG_PRINTF("range too big\n");
|
|
lookarounds.clear();
|
|
return;
|
|
}
|
|
s8 offset = verify_s8(m.first);
|
|
lookaround.emplace_back(offset, m.second);
|
|
}
|
|
lookarounds.emplace_back(lookaround);
|
|
}
|
|
}
|
|
|
|
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 checkShuftiBuckets(const vector<map<s32, CharReach>> &looks,
|
|
u32 bucket_size) {
|
|
set<u32> bucket;
|
|
for (const auto &look : looks) {
|
|
for (const auto &l : look) {
|
|
CharReach cr = l.second;
|
|
if (cr.count() > 128) {
|
|
cr.flip();
|
|
}
|
|
map <u16, u16> lo2hi;
|
|
|
|
for (size_t i = cr.find_first(); i != CharReach::npos;) {
|
|
u8 it_hi = i >> 4;
|
|
u16 low_encode = 0;
|
|
while (i != CharReach::npos && (i >> 4) == it_hi) {
|
|
low_encode |= 1 << (i &0xf);
|
|
i = cr.find_next(i);
|
|
}
|
|
lo2hi[low_encode] |= 1 << it_hi;
|
|
}
|
|
|
|
for (const auto &it : lo2hi) {
|
|
u32 hi_lo = (it.second << 16) | it.first;
|
|
bucket.insert(hi_lo);
|
|
}
|
|
}
|
|
}
|
|
DEBUG_PRINTF("shufti has %lu bucket(s)\n", bucket.size());
|
|
return bucket.size() <= bucket_size;
|
|
}
|
|
|
|
static
|
|
bool getTransientPrefixReach(const NGHolder &g, ReportID report, u32 lag,
|
|
vector<map<s32, CharReach>> &looks) {
|
|
if (!isAcyclic(g)) {
|
|
DEBUG_PRINTF("contains back-edge\n");
|
|
return false;
|
|
}
|
|
|
|
// Must be floating chains wired to startDs.
|
|
if (!isFloating(g)) {
|
|
DEBUG_PRINTF("not a floating start\n");
|
|
return false;
|
|
}
|
|
|
|
vector<NFAVertex> curr;
|
|
for (auto v : inv_adjacent_vertices_range(g.accept, g)) {
|
|
if (v == g.start || v == g.startDs) {
|
|
DEBUG_PRINTF("empty graph\n");
|
|
return true;
|
|
}
|
|
if (contains(g[v].reports, report)) {
|
|
curr.emplace_back(v);
|
|
}
|
|
}
|
|
|
|
assert(!curr.empty());
|
|
|
|
u32 total_len = curr.size();
|
|
|
|
for (const auto &v : curr) {
|
|
looks.emplace_back(map<s32, CharReach>());
|
|
looks.back()[0 - (lag + 1)] = g[v].char_reach;
|
|
}
|
|
|
|
bool curr_active = false;
|
|
|
|
/* For each offset -i, we backwardly trace the path by vertices in curr.
|
|
* Once there are more than 8 paths and more than 64 bits total_len,
|
|
* which means that neither MULTIPATH_LOOKAROUND nor MULTIPATH_SHUFTI
|
|
* could be successfully built, we will give up the path finding.
|
|
* Otherwise, the loop will halt when all vertices in curr are startDs.
|
|
*/
|
|
for (u32 i = lag + 2; i < (lag + 2) + MAX_BACK_LEN; i++) {
|
|
curr_active = false;
|
|
size_t curr_size = curr.size();
|
|
if (curr.size() > 1 && i > lag + MULTIPATH_MAX_LEN) {
|
|
DEBUG_PRINTF("range is larger than 16 in multi-path\n");
|
|
return false;
|
|
}
|
|
|
|
for (size_t idx = 0; idx < curr_size; idx++) {
|
|
NFAVertex v = curr[idx];
|
|
if (v == g.startDs) {
|
|
continue;
|
|
}
|
|
assert(!is_special(v, g));
|
|
|
|
for (auto u : inv_adjacent_vertices_range(v, g)) {
|
|
// cppcheck-suppress useStlAlgorithm
|
|
if (u == g.start || u == g.startDs) {
|
|
curr[idx] = g.startDs;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (is_special(curr[idx], g)) {
|
|
continue;
|
|
}
|
|
|
|
for (auto u : inv_adjacent_vertices_range(v, g)) {
|
|
curr_active = true;
|
|
if (curr[idx] == v) {
|
|
curr[idx] = u;
|
|
looks[idx][0 - i] = g[u].char_reach;
|
|
total_len++;
|
|
} else {
|
|
curr.emplace_back(u);
|
|
looks.emplace_back(looks[idx]);
|
|
(looks.back())[0 - i] = g[u].char_reach;
|
|
total_len += looks.back().size();
|
|
}
|
|
|
|
if (curr.size() > MAX_LOOKAROUND_PATHS && total_len > 64) {
|
|
DEBUG_PRINTF("too many branches\n");
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
if (!curr_active) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (curr_active) {
|
|
DEBUG_PRINTF("single path too long\n");
|
|
return false;
|
|
}
|
|
|
|
// More than 8 paths, check multi-path shufti.
|
|
if (curr.size() > MAX_LOOKAROUND_PATHS) {
|
|
u32 bucket_size = total_len > 32 ? 8 : 16;
|
|
if (!checkShuftiBuckets(looks, bucket_size)) {
|
|
DEBUG_PRINTF("shufti has too many buckets\n");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
assert(!looks.empty());
|
|
if (looks.size() == 1) {
|
|
DEBUG_PRINTF("single lookaround\n");
|
|
} else {
|
|
DEBUG_PRINTF("multi-path lookaround\n");
|
|
}
|
|
DEBUG_PRINTF("done\n");
|
|
return true;
|
|
}
|
|
|
|
bool makeLeftfixLookaround(const RoseBuildImpl &build, const RoseVertex v,
|
|
vector<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;
|
|
}
|
|
|
|
vector<map<s32, CharReach>> looks;
|
|
if (!getTransientPrefixReach(*leftfix.graph(), g[v].left.leftfix_report,
|
|
g[v].left.lag, looks)) {
|
|
DEBUG_PRINTF("graph has loop or too large\n");
|
|
return false;
|
|
}
|
|
|
|
if (!trimMultipathLeftfix(build, v, looks)) {
|
|
return false;
|
|
}
|
|
transToLookaround(looks, lookaround);
|
|
|
|
return !lookaround.empty();
|
|
}
|
|
|
|
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.
|
|
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
|