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vectorscan/src/nfa/limex_compile.cpp
gtsoul-tech 0f4369bf22
Bug fix/clang-tidy-performance (#300) 
Various clang-tidy-performance fixes:
* noexcept
* performance-noexcept-swap
* performance
* performance-move-const-arg
* performance-unnecessary-value-param
* performance-inefficient-vector-operation
* performance-no-int-to-ptr
* add performance
* performance-inefficient-string-concatenation
* clang-analyzer-deadcode.DeadStores
* performance-inefficient-vector-operation
* clang-analyzer-core.NullDereference
* clang-analyzer-core.UndefinedBinaryOperatorResult
* clang-analyzer-core.CallAndMessage

---------

Co-authored-by: gtsoul-tech <gtsoulkanakis@gmail.com>
2024-06-20 14:57:19 +03:00

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/*
* 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 Main NFA build code.
*/
#include "limex_compile.h"
#include "accel.h"
#include "accelcompile.h"
#include "grey.h"
#include "limex_internal.h"
#include "limex_limits.h"
#include "nfa_build_util.h"
#include "nfagraph/ng_dominators.h"
#include "nfagraph/ng_holder.h"
#include "nfagraph/ng_limex_accel.h"
#include "nfagraph/ng_repeat.h"
#include "nfagraph/ng_squash.h"
#include "nfagraph/ng_util.h"
#include "ue2common.h"
#include "repeatcompile.h"
#include "util/alloc.h"
#include "util/bitutils.h"
#include "util/bytecode_ptr.h"
#include "util/charreach.h"
#include "util/compile_context.h"
#include "util/container.h"
#include "util/flat_containers.h"
#include "util/graph.h"
#include "util/graph_range.h"
#include "util/graph_small_color_map.h"
#include "util/order_check.h"
#include "util/unordered.h"
#include "util/verify_types.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <map>
#include <set>
#include <vector>
#include <boost/graph/breadth_first_search.hpp>
#include <boost/graph/depth_first_search.hpp>
#include <boost/range/adaptor/map.hpp>
using namespace std;
using boost::adaptors::map_values;
namespace ue2 {
/**
* \brief Special state index value meaning that the vertex will not
* participate in an (NFA/DFA/etc) implementation.
*/
static constexpr u32 NO_STATE = ~0;
/* Maximum number of states taken as a small NFA */
static constexpr u32 MAX_SMALL_NFA_STATES = 64;
/* Maximum bounded repeat upper bound to consider as a fast NFA */
static constexpr u64a MAX_REPEAT_SIZE = 200;
/* Maximum bounded repeat char reach size to consider as a fast NFA */
static constexpr u32 MAX_REPEAT_CHAR_REACH = 26;
/* Minimum bounded repeat trigger distance to consider as a fast NFA */
static constexpr u8 MIN_REPEAT_TRIGGER_DISTANCE = 6;
namespace {
struct precalcAccel {
precalcAccel() : single_offset(0), double_offset(0) {}
CharReach single_cr;
u32 single_offset;
CharReach double_cr;
flat_set<pair<u8, u8>> double_lits; /* double-byte accel stop literals */
u32 double_offset;
};
struct limex_accel_info {
unordered_set<NFAVertex> accelerable;
map<NFAStateSet, precalcAccel> precalc;
unordered_map<NFAVertex, flat_set<NFAVertex>> friends;
unordered_map<NFAVertex, AccelScheme> accel_map;
};
static
unordered_map<NFAVertex, NFAStateSet>
reindexByStateId(const unordered_map<NFAVertex, NFAStateSet> &in,
const NGHolder &g,
const unordered_map<NFAVertex, u32> &state_ids,
const u32 num_states) {
unordered_map<NFAVertex, NFAStateSet> out;
out.reserve(in.size());
vector<u32> indexToState(num_vertices(g), NO_STATE);
for (const auto &m : state_ids) {
u32 vert_id = g[m.first].index;
assert(vert_id < indexToState.size());
indexToState[vert_id] = m.second;
}
for (const auto &m : in) {
NFAVertex v = m.first;
assert(m.second.size() <= indexToState.size());
NFAStateSet mask(num_states);
for (size_t i = m.second.find_first(); i != m.second.npos;
i = m.second.find_next(i)) {
u32 state_id = indexToState[i];
// cppcheck-suppress knownConditionTrueFalse
if (state_id == NO_STATE) {
continue;
}
mask.set(state_id);
}
out.emplace(v, mask);
}
return out;
}
struct build_info {
build_info(NGHolder &hi,
const unordered_map<NFAVertex, u32> &states_in,
const vector<BoundedRepeatData> &ri,
const unordered_map<NFAVertex, NFAStateSet> &rsmi,
const unordered_map<NFAVertex, NFAStateSet> &smi,
const map<u32, set<NFAVertex>> &ti, const set<NFAVertex> &zi,
bool dai, bool sci, const CompileContext &cci, u32 nsi)
: h(hi), state_ids(states_in), repeats(ri), tops(ti), tugs(nsi),
zombies(zi), do_accel(dai), stateCompression(sci), cc(cci),
num_states(nsi) {
for (const auto &br : repeats) {
for (auto v : br.tug_triggers) {
assert(state_ids.at(v) != NO_STATE);
tugs.set(state_ids.at(v));
}
br_cyclic[br.cyclic] =
BoundedRepeatSummary(br.repeatMin, br.repeatMax);
}
// Convert squash maps to be indexed by state index rather than
// vertex_index.
squashMap = reindexByStateId(smi, h, state_ids, num_states);
reportSquashMap = reindexByStateId(rsmi, h, state_ids, num_states);
}
NGHolder &h;
const unordered_map<NFAVertex, u32> &state_ids;
const vector<BoundedRepeatData> &repeats;
// Squash maps; state sets are indexed by state_id.
unordered_map<NFAVertex, NFAStateSet> reportSquashMap;
unordered_map<NFAVertex, NFAStateSet> squashMap;
const map<u32, set<NFAVertex>> &tops;
NFAStateSet tugs;
map<NFAVertex, BoundedRepeatSummary> br_cyclic;
const set<NFAVertex> &zombies;
bool do_accel;
bool stateCompression;
const CompileContext &cc;
u32 num_states;
limex_accel_info accel;
};
#define LAST_LIMEX_NFA LIMEX_NFA_512
// Constants for scoring mechanism
const int SHIFT_COST = 10; // limex: cost per shift mask
const int EXCEPTION_COST = 4; // limex: per exception
template<NFAEngineType t> struct NFATraits { };
template<template<NFAEngineType t> class sfunc, typename rv_t, typename arg_t,
NFAEngineType lb>
struct DISPATCH_BY_LIMEX_TYPE_INT {
static rv_t doOp(NFAEngineType i, const arg_t &arg) {
if (i == lb) {
return sfunc<lb>::call(arg);
} else {
return DISPATCH_BY_LIMEX_TYPE_INT<sfunc, rv_t, arg_t,
(NFAEngineType)(lb + 1)>
::doOp(i, arg);
}
}
};
template<template<NFAEngineType t> class sfunc, typename rv_t, typename arg_t>
struct DISPATCH_BY_LIMEX_TYPE_INT<sfunc, rv_t, arg_t,
(NFAEngineType)(LAST_LIMEX_NFA + 1)> {
// dummy
static rv_t doOp(NFAEngineType, const arg_t &) {
assert(0);
throw std::logic_error("Unreachable");
}
};
#define DISPATCH_BY_LIMEX_TYPE(i, op, arg) \
DISPATCH_BY_LIMEX_TYPE_INT<op, decltype(op<(NFAEngineType)0>::call(arg)), \
decltype(arg), (NFAEngineType)0>::doOp(i, arg)
// Given a number of states, find the size of the smallest container NFA it
// will fit in. We support NFAs of the following sizes: 32, 64, 128, 256, 384,
// 512.
size_t findContainerSize(size_t states) {
if (states > 256 && states <= 384) {
return 384;
}
return 1ULL << (lg2(states - 1) + 1);
}
bool isLimitedTransition(int from, int to, int maxshift) {
int diff = to - from;
// within our shift?
if (diff < 0 || diff > maxshift) {
return false;
}
// can't jump over a bollard
return (from & ~63) == (to & ~63);
}
// Fill a bit mask
template<class Mask>
void maskFill(Mask &m, u8 c) {
memset(&m, c, sizeof(m));
}
// Clear a bit mask.
template<class Mask>
void maskClear(Mask &m) {
memset(&m, 0, sizeof(m));
}
template<class Mask>
u8 *maskGetByte(Mask &m, u32 bit) {
assert(bit < sizeof(m)*8);
u8 *m8 = reinterpret_cast<u8 *>(&m);
return m8 + bit/8;
}
// Set a bit in a mask, starting from the little end.
template<class Mask>
void maskSetBit(Mask &m, const unsigned int bit) {
u8 *byte = maskGetByte(m, bit);
*byte |= 1U << (bit % 8);
}
template<class Mask>
void maskSetBits(Mask &m, const NFAStateSet &bits) {
for (size_t i = bits.find_first(); i != bits.npos; i = bits.find_next(i)) {
maskSetBit(m, i);
}
}
template<class Mask>
bool isMaskZero(Mask &m) {
const u8 *m8 = reinterpret_cast<u8 *>(&m);
for (u32 i = 0; i < sizeof(m); i++) {
if (m8[i]) {
return false;
}
}
return true;
}
// Sets an entire byte in a mask to the given value
template<class Mask>
void maskSetByte(Mask &m, const unsigned int idx, const char val) {
assert(idx < sizeof(m));
char *m8 = reinterpret_cast<char *>(&m);
char &byte = m8[idx];
byte = val;
}
// Clear a bit in the mask, starting from the little end.
template<class Mask>
void maskClearBit(Mask &m, const u32 bit) {
u8 *byte = maskGetByte(m, bit);
*byte &= ~(1U << (bit % 8));
}
/*
* Common code: the following code operates on parts of the NFA that are common
* to both the (defunct) General and the LimEx models.
*/
static
void buildReachMapping(const build_info &args, vector<NFAStateSet> &reach,
vector<u8> &reachMap) {
const NGHolder &h = args.h;
const auto &state_ids = args.state_ids;
// Build a list of vertices with a state index assigned.
vector<NFAVertex> verts;
verts.reserve(args.num_states);
auto sidat = [&state_ids=state_ids](const NFAVertex &v) {
return (state_ids.at(v) != NO_STATE);
};
const auto &vr = vertices_range(h);
std::copy_if(begin(vr), end(vr), std::back_inserter(verts), sidat);
// Build a mapping from set-of-states -> reachability.
map<NFAStateSet, CharReach> mapping;
NFAStateSet states(args.num_states);
for (size_t i = 0; i < N_CHARS; i++) {
states.reset();
for (auto v : verts) {
const CharReach &cr = h[v].char_reach;
if (cr.test(i)) {
u32 state_id = state_ids.at(v);
states.set(state_id);
}
}
mapping[states].set(i);
}
DEBUG_PRINTF("%zu distinct reachability entries\n", mapping.size());
assert(!mapping.empty());
// Build a vector of distinct reachability entries and a mapping from every
// character to one of those entries.
reach.reserve(mapping.size());
reachMap.assign(N_CHARS, 0);
u8 num = 0;
for (auto mi = mapping.begin(), me = mapping.end(); mi != me; ++mi, ++num) {
// Reach entry.
reach.emplace_back(mi->first);
// Character mapping.
const CharReach &cr = mi->second;
for (size_t i = cr.find_first(); i != CharReach::npos;
i = cr.find_next(i)) {
reachMap[i] = num;
}
}
}
struct AccelBuild {
AccelBuild() : v(NGHolder::null_vertex()), state(0), offset(0) {}
NFAVertex v;
u32 state;
u32 offset; // offset correction to apply
CharReach stop1; // single-byte accel stop literals
flat_set<pair<u8, u8>> stop2; // double-byte accel stop literals
};
static
void findStopLiterals(const build_info &bi, NFAVertex v, AccelBuild &build) {
u32 state = bi.state_ids.at(v);
build.v = v;
build.state = state;
NFAStateSet ss(bi.num_states);
ss.set(state);
if (!contains(bi.accel.precalc, ss)) {
build.stop1 = CharReach::dot();
} else {
const precalcAccel &precalc = bi.accel.precalc.at(ss);
if (precalc.double_lits.empty()) {
build.stop1 = precalc.single_cr;
build.offset = precalc.single_offset;
} else {
build.stop1 = precalc.double_cr;
build.stop2 = precalc.double_lits;
build.offset = precalc.double_offset;
}
}
#ifdef DEBUG
printf("state %u stop1:", state);
for (size_t j = build.stop1.find_first(); j != build.stop1.npos;
j = build.stop1.find_next(j)) {
printf(" 0x%02x", (u32)j);
}
printf("\n");
printf("state %u stop2:", state);
for (auto it = build.stop2.begin(); it != build.stop2.end(); ++it) {
printf(" 0x%02hhx%02hhx", it->first, it->second);
}
printf("\n");
#endif
}
// Generate all the data we need for at most NFA_MAX_ACCEL_STATES accelerable
// states.
static
void gatherAccelStates(const build_info &bi, vector<AccelBuild> &accelStates) {
for (auto v : bi.accel.accelerable) {
DEBUG_PRINTF("state %u is accelerable\n", bi.state_ids.at(v));
AccelBuild a;
findStopLiterals(bi, v, a);
accelStates.emplace_back(a);
}
// AccelStates should be sorted by state number, so that we build our accel
// masks correctly.
sort(accelStates.begin(), accelStates.end(),
[](const AccelBuild &a, const AccelBuild &b) {
return a.state < b.state;
});
// Our caller shouldn't have fed us too many accel states.
assert(accelStates.size() <= NFA_MAX_ACCEL_STATES);
if (accelStates.size() > NFA_MAX_ACCEL_STATES) {
accelStates.resize(NFA_MAX_ACCEL_STATES);
}
}
static
void combineAccel(const AccelBuild &in, AccelBuild &out) {
// stop1 and stop2 union
out.stop1 |= in.stop1;
out.stop2.insert(in.stop2.begin(), in.stop2.end());
// offset is maximum of the two
out.offset = max(out.offset, in.offset);
}
static
void minimiseAccel(AccelBuild &build) {
flat_set<pair<u8, u8>> new_stop2;
// Any two-byte accels beginning with a one-byte accel should be removed
for (const auto &si : build.stop2) {
if (!build.stop1.test(si.first)) {
new_stop2.insert(si);
}
}
build.stop2 = new_stop2;
}
struct AccelAuxCmp {
explicit AccelAuxCmp(const AccelAux &aux_in) : aux(aux_in) {}
bool operator()(const AccelAux &a) const {
return !memcmp(&a, &aux, sizeof(AccelAux));
}
private:
const AccelAux &aux;
};
static
bool allow_wide_accel(NFAVertex v, const NGHolder &g, NFAVertex sds_or_proxy) {
return v == sds_or_proxy || edge(g.start, v, g).second;
}
static
bool allow_wide_accel(const vector<NFAVertex> &vv, const NGHolder &g,
NFAVertex sds_or_proxy) {
// cppcheck-suppress useStlAlgorithm
for (auto v : vv) {
if (allow_wide_accel(v, g, sds_or_proxy)) {
return true;
}
}
return false;
}
// identify and mark states that we feel are accelerable (for a limex NFA)
/* Note: leftfix nfas allow accepts to be accelerated */
static
void nfaFindAccelSchemes(const NGHolder &g,
const map<NFAVertex, BoundedRepeatSummary> &br_cyclic,
unordered_map<NFAVertex, AccelScheme> *out) {
vector<CharReach> refined_cr = reduced_cr(g, br_cyclic);
NFAVertex sds_or_proxy = get_sds_or_proxy(g);
for (auto v : vertices_range(g)) {
// We want to skip any vertices that don't lead to at least one other
// (self-loops don't count) vertex.
if (!has_proper_successor(v, g)) {
DEBUG_PRINTF("skipping vertex %zu\n", g[v].index);
continue;
}
bool allow_wide = allow_wide_accel(v, g, sds_or_proxy);
AccelScheme as;
if (nfaCheckAccel(g, v, refined_cr, br_cyclic, &as, allow_wide)) {
DEBUG_PRINTF("graph vertex %zu is accelerable with offset %u.\n",
g[v].index, as.offset);
(*out)[v] = as;
}
}
}
struct fas_visitor : public boost::default_bfs_visitor {
fas_visitor(const unordered_map<NFAVertex, AccelScheme> &am_in,
unordered_map<NFAVertex, AccelScheme> *out_in)
: accel_map(am_in), out(out_in) {}
void discover_vertex(NFAVertex v, const NGHolder &) {
if (accel_map.find(v) != accel_map.end()) {
(*out)[v] = accel_map.find(v)->second;
}
if (out->size() >= NFA_MAX_ACCEL_STATES) {
throw this; /* done */
}
}
const unordered_map<NFAVertex, AccelScheme> &accel_map;
unordered_map<NFAVertex, AccelScheme> *out;
};
static
void filterAccelStates(NGHolder &g, const map<u32, set<NFAVertex>> &tops,
unordered_map<NFAVertex, AccelScheme> *accel_map) {
/* We want the NFA_MAX_ACCEL_STATES best acceleration states, everything
* else should be ditched. We use a simple BFS to choose accel states near
* the start. */
vector<NFAEdge> tempEdges;
for (const auto &vv : tops | map_values) {
for (NFAVertex v : vv) {
if (!edge(g.start, v, g).second) {
tempEdges.emplace_back(add_edge(g.start, v, g).first);
}
}
}
// Similarly, connect (start, startDs) if necessary.
if (!edge(g.start, g.startDs, g).second) {
NFAEdge e;
std::tie(e, std::ignore) = add_edge(g.start, g.startDs, g);
tempEdges.emplace_back(e); // Remove edge later.
}
unordered_map<NFAVertex, AccelScheme> out;
try {
boost::breadth_first_search(g, g.start,
visitor(fas_visitor(*accel_map, &out))
.color_map(make_small_color_map(g)));
} catch (fas_visitor *) {
; /* found max accel_states */
}
remove_edges(tempEdges, g);
assert(out.size() <= NFA_MAX_ACCEL_STATES);
accel_map->swap(out);
}
static
bool containsBadSubset(const limex_accel_info &accel,
const NFAStateSet &state_set, const u32 effective_sds) {
NFAStateSet subset(state_set.size());
for (size_t j = state_set.find_first(); j != state_set.npos;
j = state_set.find_next(j)) {
subset = state_set;
subset.reset(j);
// cppcheck-suppress knownConditionTrueFalse
if (effective_sds != NO_STATE && subset.count() == 1 &&
subset.test(effective_sds)) {
continue;
}
if (subset.any() && !contains(accel.precalc, subset)) {
return true;
}
}
return false;
}
static
bool is_too_wide(const AccelScheme &as) {
return as.cr.count() > MAX_MERGED_ACCEL_STOPS;
}
static
void fillAccelInfo(build_info &bi) {
if (!bi.do_accel) {
return;
}
NGHolder &g = bi.h;
limex_accel_info &accel = bi.accel;
unordered_map<NFAVertex, AccelScheme> &accel_map = accel.accel_map;
const map<NFAVertex, BoundedRepeatSummary> &br_cyclic = bi.br_cyclic;
const unordered_map<NFAVertex, u32> &state_ids = bi.state_ids;
const u32 num_states = bi.num_states;
nfaFindAccelSchemes(g, br_cyclic, &accel_map);
filterAccelStates(g, bi.tops, &accel_map);
assert(accel_map.size() <= NFA_MAX_ACCEL_STATES);
vector<CharReach> refined_cr = reduced_cr(g, br_cyclic);
vector<NFAVertex> astates;
for (const auto &m : accel_map) {
// cppcheck-suppress useStlAlgorithm
astates.emplace_back(m.first); //NOLINT (performance-inefficient-vector-operation)
}
NFAStateSet useful(num_states);
NFAStateSet state_set(num_states);
vector<NFAVertex> states;
NFAVertex sds_or_proxy = get_sds_or_proxy(g);
const u32 effective_sds = state_ids.at(sds_or_proxy);
/* for each subset of the accel keys need to find an accel scheme */
assert(astates.size() < 32);
sort(astates.begin(), astates.end());
for (u32 i = 1, i_end = 1U << astates.size(); i < i_end; i++) {
DEBUG_PRINTF("saving info for accel %u\n", i);
states.clear();
state_set.reset();
for (u32 j = 0, j_end = astates.size(); j < j_end; j++) {
if (i & (1U << j)) {
NFAVertex v = astates[j];
states.emplace_back(v);
state_set.set(state_ids.at(v));
}
}
if (containsBadSubset(accel, state_set, effective_sds)) {
DEBUG_PRINTF("accel %u has bad subset\n", i);
continue; /* if a subset failed to build we would too */
}
const bool allow_wide = allow_wide_accel(states, g, sds_or_proxy);
AccelScheme as = nfaFindAccel(g, states, refined_cr, br_cyclic,
allow_wide, true);
if (is_too_wide(as)) {
DEBUG_PRINTF("accel %u too wide (%zu, %d)\n", i,
as.cr.count(), MAX_MERGED_ACCEL_STOPS);
continue;
}
DEBUG_PRINTF("accel %u ok with offset s%u, d%u\n", i, as.offset,
as.double_offset);
precalcAccel &pa = accel.precalc[state_set];
pa.single_offset = as.offset;
pa.single_cr = as.cr;
if (as.double_byte.size() != 0) {
pa.double_offset = as.double_offset;
pa.double_lits = as.double_byte;
pa.double_cr = as.double_cr;
}
useful |= state_set;
}
for (const auto &m : accel_map) {
NFAVertex v = m.first;
const u32 state_id = state_ids.at(v);
/* if we we unable to make a scheme out of the state in any context,
* there is not point marking it as accelerable */
if (!useful.test(state_id)) {
continue;
}
u32 offset = 0;
state_set.reset();
state_set.set(state_id);
accel.accelerable.insert(v);
findAccelFriends(g, v, br_cyclic, offset, &accel.friends[v]);
}
}
/** The AccelAux structure has large alignment specified, and this makes some
* compilers do odd things unless we specify a custom allocator. */
typedef vector<AccelAux, AlignedAllocator<AccelAux, alignof(AccelAux)>>
AccelAuxVector;
#define IMPOSSIBLE_ACCEL_MASK (~0U)
static
u32 getEffectiveAccelStates(const build_info &args,
const unordered_map<NFAVertex, NFAVertex> &dom_map,
u32 active_accel_mask,
const vector<AccelBuild> &accelStates) {
/* accelStates is indexed by the acceleration bit index and contains a
* reference to the original vertex & state_id */
/* Cases to consider:
*
* 1: Accel states a and b are on and b can squash a
* --> we can ignore a. This will result in a no longer being accurately
* modelled - we may miss escapes turning it off and we may also miss
* its successors being activated.
*
* 2: Accel state b is on but accel state a is off and a is .* and must be
* seen before b is reached (and would not be covered by (1))
* --> if a is squashable (or may die unexpectedly) we should continue
* as is
* --> if a is not squashable we can treat this as a+b or as a no accel,
* impossible case
* --> this case could be extended to handle non dot reaches by
* effectively creating something similar to squash masks for the
* reverse graph
*
*
* Other cases:
*
* 3: Accel states a and b are on but have incompatible reaches
* --> we should treat this as an impossible case. Actually, this case
* is unlikely to arise as we pick states with wide reaches to
* accelerate so an empty intersection is unlikely.
*
* Note: we need to be careful when dealing with accel states corresponding
* to bounded repeat cyclics - they may 'turn off' based on a max bound and
* so we may still require on earlier states to be accurately modelled.
*/
const NGHolder &h = args.h;
/* map from accel_id to mask of accel_ids that it is dominated by */
vector<u32> dominated_by(accelStates.size());
map<NFAVertex, u32> accel_id_map;
for (u32 accel_id = 0; accel_id < accelStates.size(); accel_id++) {
NFAVertex v = accelStates[accel_id].v;
accel_id_map[v] = accel_id;
}
/* Note: we want a slightly less strict defn of dominate as skip edges
* prevent .* 'truly' dominating */
for (u32 local_accel_mask = active_accel_mask; local_accel_mask; ) {
u32 accel_id = findAndClearLSB_32(&local_accel_mask);
assert(accel_id < accelStates.size());
NFAVertex v = accelStates[accel_id].v;
while (contains(dom_map, v) && dom_map.at(v)) {
v = dom_map.at(v);
if (contains(accel_id_map, v)) {
dominated_by[accel_id] |= 1U << accel_id_map[v];
}
/* TODO: could also look at inv_adj vertices to handle fan-in */
for (NFAVertex a : adjacent_vertices_range(v, h)) {
if (a == v || !contains(accel_id_map, a)
|| a == accelStates[accel_id].v /* not likely */) {
continue;
}
if (!is_subset_of(h[v].reports, h[a].reports)) {
continue;
}
auto v_succ = succs(v, h);
auto a_succ = succs(a, h);
if (is_subset_of(v_succ, a_succ)) {
dominated_by[accel_id] |= 1U << accel_id_map[a];
}
}
}
}
u32 may_turn_off = 0; /* BR with max bound, non-dots, squashed, etc */
for (u32 local_accel_mask = active_accel_mask; local_accel_mask; ) {
u32 accel_id = findAndClearLSB_32(&local_accel_mask);
NFAVertex v = accelStates[accel_id].v;
u32 state_id = accelStates[accel_id].state;
assert(contains(args.accel.accelerable, v));
if (!h[v].char_reach.all()) {
may_turn_off |= 1U << accel_id;
continue;
}
if (contains(args.br_cyclic, v)
&& args.br_cyclic.at(v).repeatMax != depth::infinity()) {
may_turn_off |= 1U << accel_id;
continue;
}
for (const auto &s_mask : args.squashMap | map_values) {
// cppcheck-suppress useStlAlgorithm
if (!s_mask.test(state_id)) {
may_turn_off |= 1U << accel_id;
break;
}
}
for (const auto &s_mask : args.reportSquashMap | map_values) {
// cppcheck-suppress useStlAlgorithm
if (!s_mask.test(state_id)) {
may_turn_off |= 1U << accel_id;
break;
}
}
}
/* Case 1: */
u32 ignored = 0;
for (u32 local_accel_mask = active_accel_mask; local_accel_mask; ) {
u32 accel_id_b = findAndClearLSB_32(&local_accel_mask);
NFAVertex v = accelStates[accel_id_b].v;
if (!contains(args.squashMap, v)) {
continue;
}
assert(!contains(args.br_cyclic, v)
|| args.br_cyclic.at(v).repeatMax == depth::infinity());
NFAStateSet squashed = args.squashMap.at(v);
squashed.flip(); /* default sense for mask of survivors */
for (u32 local_accel_mask2 = active_accel_mask; local_accel_mask2; ) {
u32 accel_id_a = findAndClearLSB_32(&local_accel_mask2);
if (squashed.test(accelStates[accel_id_a].state)) {
ignored |= 1U << accel_id_a;
}
}
}
/* Case 2: */
for (u32 local_accel_mask = active_accel_mask; local_accel_mask; ) {
u32 accel_id = findAndClearLSB_32(&local_accel_mask);
u32 stuck_dominators = dominated_by[accel_id] & ~may_turn_off;
if ((stuck_dominators & active_accel_mask) != stuck_dominators) {
DEBUG_PRINTF("only %08x on, but we require %08x\n",
active_accel_mask, stuck_dominators);
return IMPOSSIBLE_ACCEL_MASK;
}
}
if (ignored) {
DEBUG_PRINTF("in %08x, ignoring %08x\n", active_accel_mask, ignored);
}
return active_accel_mask & ~ignored;
}
static
void buildAccel(const build_info &args, NFAStateSet &accelMask,
NFAStateSet &accelFriendsMask, AccelAuxVector &auxvec,
vector<u8> &accelTable) {
const limex_accel_info &accel = args.accel;
// Init, all zeroes.
accelMask.resize(args.num_states);
accelFriendsMask.resize(args.num_states);
if (!args.do_accel) {
return;
}
vector<AccelBuild> accelStates;
gatherAccelStates(args, accelStates);
if (accelStates.empty()) {
DEBUG_PRINTF("no accelerable states\n");
return;
}
const auto dom_map = findDominators(args.h);
// We have 2^n different accel entries, one for each possible
// combination of accelerable states.
assert(accelStates.size() < 32);
const u32 accelCount = 1U << accelStates.size();
assert(accelCount <= 256);
// Set up a unioned AccelBuild for every possible combination of the set
// bits in accelStates.
vector<AccelBuild> accelOuts(accelCount);
vector<u32> effective_accel_set;
effective_accel_set.emplace_back(0); /* empty is effectively empty */
for (u32 i = 1; i < accelCount; i++) {
u32 effective_i = getEffectiveAccelStates(args, dom_map, i,
accelStates);
effective_accel_set.emplace_back(effective_i);
if (effective_i == IMPOSSIBLE_ACCEL_MASK) {
DEBUG_PRINTF("this combination of accel states is not possible\n");
accelOuts[i].stop1 = CharReach::dot();
continue;
}
while (effective_i) {
u32 base_accel_state = findAndClearLSB_32(&effective_i);
combineAccel(accelStates[base_accel_state], accelOuts[i]);
}
minimiseAccel(accelOuts[i]);
}
accelTable.resize(accelCount);
// We dedupe our AccelAux structures here, so that we only write one copy
// of each unique accel scheme into the bytecode, using the accelTable as
// an index.
// Start with the NONE case.
auxvec.emplace_back(AccelAux());
memset(&auxvec[0], 0, sizeof(AccelAux));
auxvec[0].accel_type = ACCEL_NONE; // no states on.
AccelAux aux;
for (u32 i = 1; i < accelCount; i++) {
memset(&aux, 0, sizeof(aux));
NFAStateSet effective_states(args.num_states);
u32 effective_i = effective_accel_set[i];
AccelInfo ainfo;
ainfo.double_offset = accelOuts[i].offset;
ainfo.double_stop1 = accelOuts[i].stop1;
ainfo.double_stop2 = accelOuts[i].stop2;
if (effective_i != IMPOSSIBLE_ACCEL_MASK) {
while (effective_i) {
u32 base_accel_id = findAndClearLSB_32(&effective_i);
effective_states.set(accelStates[base_accel_id].state);
}
if (contains(accel.precalc, effective_states)) {
const auto &precalc = accel.precalc.at(effective_states);
ainfo.single_offset = precalc.single_offset;
ainfo.single_stops = precalc.single_cr;
}
}
buildAccelAux(ainfo, &aux);
// FIXME: We may want a faster way to find AccelAux structures that
// we've already built before.
auto it = find_if(auxvec.begin(), auxvec.end(), AccelAuxCmp(aux));
if (it == auxvec.end()) {
accelTable[i] = verify_u8(auxvec.size());
auxvec.emplace_back(aux);
} else {
accelTable[i] = verify_u8(it - auxvec.begin());
}
}
DEBUG_PRINTF("%zu unique accel schemes (of max %u)\n", auxvec.size(),
accelCount);
// XXX: ACCEL_NONE?
for (const auto &as : accelStates) {
NFAVertex v = as.v;
assert(v && args.state_ids.at(v) == as.state);
accelMask.set(as.state);
accelFriendsMask.set(as.state);
if (!contains(accel.friends, v)) {
continue;
}
// Add the friends of this state to the friends mask.
const flat_set<NFAVertex> &friends = accel.friends.at(v);
DEBUG_PRINTF("%u has %zu friends\n", as.state, friends.size());
for (auto friend_v : friends) {
u32 state_id = args.state_ids.at(friend_v);
DEBUG_PRINTF("--> %u\n", state_id);
accelFriendsMask.set(state_id);
}
}
}
static
u32 addSquashMask(const build_info &args, const NFAVertex &v,
vector<NFAStateSet> &squash) {
auto sit = args.reportSquashMap.find(v);
if (sit == args.reportSquashMap.end()) {
return MO_INVALID_IDX;
}
// This state has a squash mask. Paw through the existing vector to
// see if we've already seen it, otherwise add a new one.
auto it = find(squash.begin(), squash.end(), sit->second);
if (it != squash.end()) {
return verify_u32(std::distance(squash.begin(), it));
}
u32 idx = verify_u32(squash.size());
squash.emplace_back(sit->second);
return idx;
}
using ReportListCache = ue2_unordered_map<vector<ReportID>, u32>;
static
u32 addReports(const flat_set<ReportID> &r, vector<ReportID> &reports,
ReportListCache &reports_cache) {
assert(!r.empty());
vector<ReportID> my_reports(begin(r), end(r));
my_reports.emplace_back(MO_INVALID_IDX); // sentinel
auto cache_it = reports_cache.find(my_reports);
if (cache_it != end(reports_cache)) {
u32 offset = cache_it->second;
DEBUG_PRINTF("reusing cached report list at %u\n", offset);
return offset;
}
auto it = search(begin(reports), end(reports), begin(my_reports),
end(my_reports));
if (it != end(reports)) {
u32 offset = verify_u32(std::distance(begin(reports), it));
DEBUG_PRINTF("reusing found report list at %u\n", offset);
return offset;
}
u32 offset = verify_u32(reports.size());
insert(&reports, reports.end(), my_reports);
reports_cache.emplace(std::move(my_reports), offset);
return offset;
}
static
void buildAcceptsList(const build_info &args, ReportListCache &reports_cache,
vector<NFAVertex> &verts, vector<NFAAccept> &accepts,
vector<ReportID> &reports, vector<NFAStateSet> &squash) {
if (verts.empty()) {
return;
}
DEBUG_PRINTF("building accept lists for %zu states\n", verts.size());
auto cmp_state_id = [&args](NFAVertex a, NFAVertex b) {
u32 a_state = args.state_ids.at(a);
u32 b_state = args.state_ids.at(b);
assert(a_state != b_state || a == b);
return a_state < b_state;
};
sort(begin(verts), end(verts), cmp_state_id);
const NGHolder &h = args.h;
for (const auto &v : verts) {
DEBUG_PRINTF("state=%u, reports: [%s]\n", args.state_ids.at(v),
as_string_list(h[v].reports).c_str());
NFAAccept a;
memset(&a, 0, sizeof(a));
assert(!h[v].reports.empty());
if (h[v].reports.size() == 1) {
a.single_report = 1;
a.reports = *h[v].reports.begin();
} else {
a.single_report = 0;
a.reports = addReports(h[v].reports, reports, reports_cache);
}
a.squash = addSquashMask(args, v, squash);
accepts.emplace_back(a);
}
}
static
void buildAccepts(const build_info &args, ReportListCache &reports_cache,
NFAStateSet &acceptMask, NFAStateSet &acceptEodMask,
vector<NFAAccept> &accepts, vector<NFAAccept> &acceptsEod,
vector<ReportID> &reports, vector<NFAStateSet> &squash) {
const NGHolder &h = args.h;
acceptMask.resize(args.num_states);
acceptEodMask.resize(args.num_states);
vector<NFAVertex> verts_accept, verts_accept_eod;
for (auto v : vertices_range(h)) {
u32 state_id = args.state_ids.at(v);
// cppcheck-suppress knownConditionTrueFalse
if (state_id == NO_STATE || !is_match_vertex(v, h)) {
continue;
}
if (edge(v, h.accept, h).second) {
acceptMask.set(state_id);
verts_accept.emplace_back(v);
} else {
assert(edge(v, h.acceptEod, h).second);
acceptEodMask.set(state_id);
verts_accept_eod.emplace_back(v);
}
}
buildAcceptsList(args, reports_cache, verts_accept, accepts, reports,
squash);
buildAcceptsList(args, reports_cache, verts_accept_eod, acceptsEod, reports,
squash);
}
static
void buildTopMasks(const build_info &args, vector<NFAStateSet> &topMasks) {
if (args.tops.empty()) {
return; // No tops, probably an outfix NFA.
}
u32 numMasks = args.tops.rbegin()->first + 1; // max mask index
DEBUG_PRINTF("we have %u top masks\n", numMasks);
topMasks.assign(numMasks, NFAStateSet(args.num_states)); // all zeroes
for (const auto &m : args.tops) {
u32 mask_idx = m.first;
for (NFAVertex v : m.second) {
u32 state_id = args.state_ids.at(v);
DEBUG_PRINTF("state %u is in top mask %u\n", state_id, mask_idx);
assert(mask_idx < numMasks);
assert(state_id != NO_STATE);
topMasks[mask_idx].set(state_id);
}
}
}
static
u32 uncompressedStateSize(u32 num_states) {
// Number of bytes required to store all our states.
return ROUNDUP_N(num_states, 8)/8;
}
static
u32 compressedStateSize(const NGHolder &h, const NFAStateSet &maskedStates,
const unordered_map<NFAVertex, u32> &state_ids) {
// Shrink state requirement to enough to fit the compressed largest reach.
vector<u32> allreach(N_CHARS, 0);
for (auto v : vertices_range(h)) {
u32 i = state_ids.at(v);
// cppcheck-suppress knownConditionTrueFalse
if (i == NO_STATE || maskedStates.test(i)) {
continue;
}
const CharReach &cr = h[v].char_reach;
for (size_t j = cr.find_first(); j != cr.npos; j = cr.find_next(j)) {
allreach[j]++; // state 'i' can reach character 'j'.
}
}
u32 maxreach = *max_element(allreach.begin(), allreach.end());
DEBUG_PRINTF("max reach is %u\n", maxreach);
return (maxreach + 7) / 8;
}
static
bool hasSquashableInitDs(const build_info &args) {
const NGHolder &h = args.h;
if (args.squashMap.empty()) {
DEBUG_PRINTF("squash map is empty\n");
return false;
}
NFAStateSet initDs(args.num_states);
u32 sds_state = args.state_ids.at(h.startDs);
// cppcheck-suppress knownConditionTrueFalse
if (sds_state == NO_STATE) {
DEBUG_PRINTF("no states in initds\n");
return false;
}
initDs.set(sds_state);
/* TODO: simplify */
// Check normal squash map.
for (const auto &m : args.squashMap) {
DEBUG_PRINTF("checking squash mask for state %u\n",
args.state_ids.at(m.first));
NFAStateSet squashed = ~(m.second); // flip mask
assert(squashed.size() == initDs.size());
if (squashed.intersects(initDs)) {
DEBUG_PRINTF("state %u squashes initds states\n",
args.state_ids.at(m.first));
return true;
}
}
// Check report squash map.
for (const auto &m : args.reportSquashMap) {
DEBUG_PRINTF("checking report squash mask for state %u\n",
args.state_ids.at(m.first));
NFAStateSet squashed = ~(m.second); // flip mask
assert(squashed.size() == initDs.size());
if (squashed.intersects(initDs)) {
DEBUG_PRINTF("state %u squashes initds states\n",
args.state_ids.at(m.first));
return true;
}
}
return false;
}
static
bool hasInitDsStates(const NGHolder &h,
const unordered_map<NFAVertex, u32> &state_ids) {
if (state_ids.at(h.startDs) != NO_STATE) {
return true;
}
if (is_triggered(h) && state_ids.at(h.start) != NO_STATE) {
return true;
}
return false;
}
static
void findMaskedCompressionStates(const build_info &args,
NFAStateSet &maskedStates) {
const NGHolder &h = args.h;
if (!generates_callbacks(h)) {
// Rose leftfixes can mask out initds, which is worth doing if it will
// stay on forever (i.e. it's not squashable).
u32 sds_i = args.state_ids.at(h.startDs);
// cppcheck-suppress knownConditionTrueFalse
if (sds_i != NO_STATE && !hasSquashableInitDs(args)) {
maskedStates.set(sds_i);
DEBUG_PRINTF("masking out initds state\n");
}
}
// Suffixes and outfixes can mask out leaf states, which should all be
// accepts. Right now we can only do this when there is nothing in initDs,
// as we switch that on unconditionally in the expand call.
if (!inspects_states_for_accepts(h)
&& !hasInitDsStates(h, args.state_ids)) {
NFAStateSet nonleaf(args.num_states);
for (const auto &e : edges_range(h)) {
u32 from = args.state_ids.at(source(e, h));
u32 to = args.state_ids.at(target(e, h));
// cppcheck-suppress knownConditionTrueFalse
if (from == NO_STATE) {
continue;
}
// We cannot mask out EOD accepts, as they have to perform an
// action after they're switched on that may be delayed until the
// next stream write.
// cppcheck-suppress knownConditionTrueFalse
if (to == NO_STATE && target(e, h) != h.acceptEod) {
continue;
}
nonleaf.set(from);
}
for (u32 i = 0; i < args.num_states; i++) {
if (!nonleaf.test(i)) {
maskedStates.set(i);
}
}
DEBUG_PRINTF("masking out %zu leaf states\n", maskedStates.count());
}
}
/** \brief Sets a given flag in the LimEx structure. */
template<class implNFA_t>
static
void setLimexFlag(implNFA_t *limex, u32 flag) {
assert(flag);
assert((flag & (flag - 1)) == 0);
limex->flags |= flag;
}
/** \brief Sets a given flag in the NFA structure */
static
void setNfaFlag(NFA *nfa, u32 flag) {
assert(flag);
assert((flag & (flag - 1)) == 0);
nfa->flags |= flag;
}
// Some of our NFA types support compressing the state down if we're not using
// all of it.
template<class implNFA_t>
static
void findStateSize(const build_info &args, implNFA_t *limex) {
// Nothing is masked off by default.
maskFill(limex->compressMask, 0xff);
u32 sizeUncompressed = uncompressedStateSize(args.num_states);
assert(sizeUncompressed <= sizeof(limex->compressMask));
if (!args.stateCompression) {
DEBUG_PRINTF("compression disabled, uncompressed state size %u\n",
sizeUncompressed);
limex->stateSize = sizeUncompressed;
return;
}
NFAStateSet maskedStates(args.num_states);
findMaskedCompressionStates(args, maskedStates);
u32 sizeCompressed = compressedStateSize(args.h, maskedStates, args.state_ids);
assert(sizeCompressed <= sizeof(limex->compressMask));
DEBUG_PRINTF("compressed=%u, uncompressed=%u\n", sizeCompressed,
sizeUncompressed);
// Must be at least a 10% saving.
if ((sizeCompressed * 100) <= (sizeUncompressed * 90)) {
DEBUG_PRINTF("using compression, state size %u\n",
sizeCompressed);
setLimexFlag(limex, LIMEX_FLAG_COMPRESS_STATE);
limex->stateSize = sizeCompressed;
if (maskedStates.any()) {
DEBUG_PRINTF("masking %zu states\n", maskedStates.count());
setLimexFlag(limex, LIMEX_FLAG_COMPRESS_MASKED);
for (size_t i = maskedStates.find_first(); i != NFAStateSet::npos;
i = maskedStates.find_next(i)) {
maskClearBit(limex->compressMask, i);
}
}
} else {
DEBUG_PRINTF("not using compression, state size %u\n",
sizeUncompressed);
limex->stateSize = sizeUncompressed;
}
}
/*
* LimEx NFA: code for building NFAs in the Limited+Exceptional model. Most
* transitions are limited, with transitions outside the constraints of our
* shifts taken care of as 'exceptions'. Exceptions are also used to handle
* accepts and squash behaviour.
*/
/**
* \brief Prototype exception class.
*
* Used to build up the map of exceptions before being converted to real
* NFAException32 (etc) structures.
*/
struct ExceptionProto {
u32 reports_index = MO_INVALID_IDX;
NFAStateSet succ_states;
NFAStateSet squash_states;
u32 repeat_index = MO_INVALID_IDX;
enum LimExTrigger trigger = LIMEX_TRIGGER_NONE;
enum LimExSquash squash = LIMEX_SQUASH_NONE;
explicit ExceptionProto(u32 num_states)
: succ_states(num_states), squash_states(num_states) {
// Squash states are represented as the set of states to leave on,
// so we start with all-ones.
squash_states.set();
}
bool operator<(const ExceptionProto &b) const {
const ExceptionProto &a = *this;
ORDER_CHECK(reports_index);
ORDER_CHECK(repeat_index);
ORDER_CHECK(trigger);
ORDER_CHECK(squash);
ORDER_CHECK(succ_states);
ORDER_CHECK(squash_states);
return false;
}
};
static
u32 buildExceptionMap(const build_info &args, ReportListCache &reports_cache,
const unordered_set<NFAEdge> &exceptional,
map<ExceptionProto, vector<u32>> &exceptionMap,
vector<ReportID> &reportList) {
const NGHolder &h = args.h;
const u32 num_states = args.num_states;
u32 exceptionCount = 0;
unordered_map<NFAVertex, u32> pos_trigger;
unordered_map<NFAVertex, u32> tug_trigger;
for (u32 i = 0; i < args.repeats.size(); i++) {
const BoundedRepeatData &br = args.repeats[i];
assert(!contains(pos_trigger, br.pos_trigger));
pos_trigger[br.pos_trigger] = i;
for (auto v : br.tug_triggers) {
assert(!contains(tug_trigger, v));
tug_trigger[v] = i;
}
}
for (auto v : vertices_range(h)) {
const u32 i = args.state_ids.at(v);
// cppcheck-suppress knownConditionTrueFalse
if (i == NO_STATE) {
continue;
}
bool addMe = false;
ExceptionProto e(num_states);
if (edge(v, h.accept, h).second && generates_callbacks(h)) {
/* if nfa is never used to produce callbacks, no need to mark
* states as exceptional */
const auto &reports = h[v].reports;
DEBUG_PRINTF("state %u is exceptional due to accept "
"(%zu reports)\n", i, reports.size());
if (reports.empty()) {
e.reports_index = MO_INVALID_IDX;
} else {
e.reports_index =
addReports(reports, reportList, reports_cache);
}
// We may be applying a report squash too.
auto mi = args.reportSquashMap.find(v);
if (mi != args.reportSquashMap.end()) {
DEBUG_PRINTF("report squashes states\n");
assert(e.squash_states.size() == mi->second.size());
e.squash_states = mi->second;
e.squash = LIMEX_SQUASH_REPORT;
}
addMe = true;
}
if (contains(pos_trigger, v)) {
u32 repeat_index = pos_trigger[v];
assert(e.trigger == LIMEX_TRIGGER_NONE);
e.trigger = LIMEX_TRIGGER_POS;
e.repeat_index = repeat_index;
DEBUG_PRINTF("state %u has pos trigger for repeat %u\n", i,
repeat_index);
addMe = true;
}
if (contains(tug_trigger, v)) {
u32 repeat_index = tug_trigger[v];
assert(e.trigger == LIMEX_TRIGGER_NONE);
e.trigger = LIMEX_TRIGGER_TUG;
e.repeat_index = repeat_index;
// TUG triggers can squash the preceding cyclic state.
u32 cyclic = args.state_ids.at(args.repeats[repeat_index].cyclic);
e.squash_states.reset(cyclic);
e.squash = LIMEX_SQUASH_TUG;
DEBUG_PRINTF("state %u has tug trigger for repeat %u, can squash "
"state %u\n", i, repeat_index, cyclic);
addMe = true;
}
// are we a non-limited transition?
for (const auto &oe : out_edges_range(v, h)) {
if (contains(exceptional, oe)) {
NFAVertex w = target(oe, h);
u32 w_idx = args.state_ids.at(w);
assert(w_idx != NO_STATE);
e.succ_states.set(w_idx);
DEBUG_PRINTF("exceptional transition %u->%u\n", i, w_idx);
addMe = true;
}
}
// do we lead SOLELY to a squasher state? (we use the successors as
// a proxy for the out-edge here, so there must be only one for us
// to do this safely)
/* The above comment is IMHO bogus and would result in all squashing
* being disabled around stars */
if (e.trigger != LIMEX_TRIGGER_TUG) {
for (auto w : adjacent_vertices_range(v, h)) {
if (w == v) {
continue;
}
u32 j = args.state_ids.at(w);
// j can be NO_STATE if args.state_ids.at(w) returns NO_STATE
// cppcheck-suppress knownConditionTrueFalse
if (j == NO_STATE) {
continue;
}
DEBUG_PRINTF("we are checking if succ %u is a squasher\n", j);
auto mi = args.squashMap.find(w);
if (mi != args.squashMap.end()) {
DEBUG_PRINTF("squasher edge (%u, %u)\n", i, j);
DEBUG_PRINTF("e.squash_states.size() == %zu, "
"mi->second.size() = %zu\n",
e.squash_states.size(), mi->second.size());
assert(e.squash_states.size() == mi->second.size());
e.squash_states = mi->second;
// NOTE: this might be being combined with the report
// squashing above.
e.squash = LIMEX_SQUASH_CYCLIC;
DEBUG_PRINTF("squashing succ %u (turns off %zu states)\n",
j, mi->second.size() - mi->second.count());
addMe = true;
}
}
}
if (addMe) {
// Add 'e' if it isn't in the map, and push state i on to its list
// of states.
assert(e.succ_states.size() == num_states);
assert(e.squash_states.size() == num_states);
exceptionMap[e].emplace_back(i);
exceptionCount++;
}
}
DEBUG_PRINTF("%u exceptions found (%zu unique)\n", exceptionCount,
exceptionMap.size());
return exceptionCount;
}
static
u32 depth_to_u32(const depth &d) {
assert(d.is_reachable());
if (d.is_infinite()) {
return REPEAT_INF;
}
u32 d_val = d;
assert(d_val < REPEAT_INF);
return d_val;
}
static
bool isExceptionalTransition(u32 from, u32 to, const build_info &args,
u32 maxShift) {
if (!isLimitedTransition(from, to, maxShift)) {
return true;
}
// All transitions out of a tug trigger are exceptional.
if (args.tugs.test(from)) {
return true;
}
return false;
}
static
u32 findMaxVarShift(const build_info &args, u32 nShifts) {
const NGHolder &h = args.h;
u32 shiftMask = 0;
for (const auto &e : edges_range(h)) {
u32 from = args.state_ids.at(source(e, h));
u32 to = args.state_ids.at(target(e, h));
// cppcheck-suppress knownConditionTrueFalse
if (from == NO_STATE || to == NO_STATE) {
continue;
}
if (!isExceptionalTransition(from, to, args, MAX_SHIFT_AMOUNT)) {
shiftMask |= (1UL << (to - from));
}
}
u32 maxVarShift = 0;
for (u32 shiftCnt = 0; shiftMask != 0 && shiftCnt < nShifts; shiftCnt++) {
maxVarShift = findAndClearLSB_32(&shiftMask);
}
return maxVarShift;
}
static
int getLimexScore(const build_info &args, u32 nShifts) {
const NGHolder &h = args.h;
u32 maxVarShift;
int score = 0;
score += SHIFT_COST * nShifts;
maxVarShift = findMaxVarShift(args, nShifts);
NFAStateSet exceptionalStates(args.num_states);
for (const auto &e : edges_range(h)) {
u32 from = args.state_ids.at(source(e, h));
u32 to = args.state_ids.at(target(e, h));
// cppcheck-suppress knownConditionTrueFalse
if (from == NO_STATE || to == NO_STATE) {
continue;
}
if (isExceptionalTransition(from, to, args, maxVarShift)) {
exceptionalStates.set(from);
}
}
score += EXCEPTION_COST * exceptionalStates.count();
return score;
}
// This function finds the best shift scheme with highest score
// Returns number of shifts and score calculated for appropriate scheme
// Returns zero if no appropriate scheme was found
static
u32 findBestNumOfVarShifts(const build_info &args,
int *bestScoreRet = nullptr) {
u32 bestNumOfVarShifts = 0;
int bestScore = INT_MAX;
for (u32 shiftCount = 1; shiftCount <= MAX_SHIFT_COUNT; shiftCount++) {
int score = getLimexScore(args, shiftCount);
if (score < bestScore) {
bestScore = score;
bestNumOfVarShifts = shiftCount;
}
}
if (bestScoreRet != nullptr) {
*bestScoreRet = bestScore;
}
return bestNumOfVarShifts;
}
static
bool cannotDie(const build_info &args, const set<NFAVertex> &tops) {
const auto &h = args.h;
// When this top is activated, all of the vertices in 'tops' are switched
// on. If any of those lead to a graph that cannot die, then this top
// cannot die.
// For each top, we use a depth-first search to traverse the graph from the
// top, looking for a cyclic path consisting of vertices of dot reach. If
// one exists, than the NFA cannot die after this top is triggered.
auto colour_map = make_small_color_map(h);
struct CycleFound {};
struct CannotDieVisitor : public boost::default_dfs_visitor {
void back_edge(const NFAEdge &e, const NGHolder &g) const {
DEBUG_PRINTF("back-edge %zu,%zu\n", g[source(e, g)].index,
g[target(e, g)].index);
if (g[target(e, g)].char_reach.all()) {
assert(g[source(e, g)].char_reach.all());
throw CycleFound();
}
}
};
try {
for (const auto &top : tops) {
DEBUG_PRINTF("checking top vertex %zu\n", h[top].index);
// Constrain the search to the top vertices and any dot vertices it
// can reach.
auto term_func = [&](NFAVertex v, const NGHolder &g) {
if (v == top) {
return false;
}
if (!g[v].char_reach.all()) {
return true;
}
if (contains(args.br_cyclic, v) &&
args.br_cyclic.at(v).repeatMax != depth::infinity()) {
// Bounded repeat vertices without inf max can be turned
// off.
return true;
}
return false;
};
boost::depth_first_visit(h, top, CannotDieVisitor(), colour_map,
term_func);
}
} catch (const CycleFound &) {
DEBUG_PRINTF("cycle found\n");
return true;
}
return false;
}
/** \brief True if this NFA cannot ever be in no states at all. */
static
bool cannotDie(const build_info &args) {
const auto &h = args.h;
const auto &state_ids = args.state_ids;
// If we have a startDs we're actually using, we can't die.
if (state_ids.at(h.startDs) != NO_STATE) {
DEBUG_PRINTF("is using startDs\n");
return true;
}
return all_of_in(args.tops | map_values, [&](const set<NFAVertex> &verts) {
return cannotDie(args, verts);
});
}
template<NFAEngineType dtype>
struct Factory {
// typedefs for readability, for types derived from traits
typedef typename NFATraits<dtype>::exception_t exception_t;
typedef typename NFATraits<dtype>::implNFA_t implNFA_t;
typedef typename NFATraits<dtype>::tableRow_t tableRow_t;
static
void allocState(NFA *nfa, u32 repeatscratchStateSize,
u32 repeatStreamState) {
const implNFA_t *limex = reinterpret_cast<implNFA_t *>(getMutableImplNfa(nfa));
// LimEx NFAs now store the following in state:
// 1. state bitvector (always present)
// 2. space associated with repeats
// This function just needs to size these correctly.
u32 stateSize = limex->stateSize;
DEBUG_PRINTF("bitvector=%zu/%u, repeat full=%u, stream=%u\n",
sizeof(limex->init), stateSize, repeatscratchStateSize,
repeatStreamState);
size_t scratchStateSize = NFATraits<dtype>::scratch_state_size;
if (repeatscratchStateSize) {
scratchStateSize
= ROUNDUP_N(scratchStateSize, alignof(RepeatControl));
scratchStateSize += repeatscratchStateSize;
}
size_t streamStateSize = stateSize + repeatStreamState;
nfa->scratchStateSize = verify_u32(scratchStateSize);
nfa->streamStateSize = verify_u32(streamStateSize);
}
static
size_t repeatAllocSize(const BoundedRepeatData &br, u32 *tableOffset,
u32 *tugMaskOffset) {
size_t len = sizeof(NFARepeatInfo) + sizeof(RepeatInfo);
// sparse lookup table.
if (br.type == REPEAT_SPARSE_OPTIMAL_P) {
len = ROUNDUP_N(len, alignof(u64a));
*tableOffset = verify_u32(len);
len += sizeof(u64a) * (br.repeatMax + 1);
} else {
*tableOffset = 0;
}
// tug mask.
len = ROUNDUP_N(len, alignof(tableRow_t));
*tugMaskOffset = verify_u32(len);
len += sizeof(tableRow_t);
// to simplify layout.
len = ROUNDUP_CL(len);
return len;
}
static
void buildRepeats(const build_info &args,
vector<bytecode_ptr<NFARepeatInfo>> &out,
u32 *scratchStateSize, u32 *streamState) {
out.reserve(args.repeats.size());
u32 repeat_idx = 0;
for (auto it = args.repeats.begin(), ite = args.repeats.end();
it != ite; ++it, ++repeat_idx) {
const BoundedRepeatData &br = *it;
assert(args.state_ids.at(br.cyclic) != NO_STATE);
u32 tableOffset, tugMaskOffset;
size_t len = repeatAllocSize(br, &tableOffset, &tugMaskOffset);
auto info = make_zeroed_bytecode_ptr<NFARepeatInfo>(len);
char *info_ptr = reinterpret_cast<char *>(info.get());
// Collect state space info.
RepeatStateInfo rsi(br.type, br.repeatMin, br.repeatMax, br.minPeriod);
u32 streamStateLen = rsi.packedCtrlSize + rsi.stateSize;
// Fill the NFARepeatInfo structure.
info->cyclicState = args.state_ids.at(br.cyclic);
info->ctrlIndex = repeat_idx;
info->packedCtrlOffset = *streamState;
info->stateOffset = *streamState + rsi.packedCtrlSize;
info->stateSize = streamStateLen;
info->tugMaskOffset = tugMaskOffset;
// Fill the RepeatInfo structure.
RepeatInfo *repeat = reinterpret_cast<RepeatInfo *>(info_ptr + sizeof(NFARepeatInfo));
repeat->type = br.type;
repeat->repeatMin = depth_to_u32(br.repeatMin);
repeat->repeatMax = depth_to_u32(br.repeatMax);
repeat->horizon = rsi.horizon;
repeat->packedCtrlSize = rsi.packedCtrlSize;
repeat->stateSize = rsi.stateSize;
copy_bytes(repeat->packedFieldSizes, rsi.packedFieldSizes);
repeat->patchCount = rsi.patchCount;
repeat->patchSize = rsi.patchSize;
repeat->encodingSize = rsi.encodingSize;
repeat->patchesOffset = rsi.patchesOffset;
u32 repeat_len = sizeof(RepeatInfo);
if (br.type == REPEAT_SPARSE_OPTIMAL_P) {
repeat_len += sizeof(u64a) * (rsi.patchSize + 1);
}
repeat->length = repeat_len;
// Copy in the sparse lookup table.
if (br.type == REPEAT_SPARSE_OPTIMAL_P) {
assert(!rsi.table.empty());
copy_bytes(info_ptr + tableOffset, rsi.table);
}
// Fill the tug mask.
tableRow_t *tugMask = reinterpret_cast<tableRow_t *>(info_ptr + tugMaskOffset);
for (auto v : br.tug_triggers) {
u32 state_id = args.state_ids.at(v);
assert(state_id != NO_STATE);
maskSetBit(*tugMask, state_id);
}
assert(streamStateLen);
*streamState += streamStateLen;
*scratchStateSize += sizeof(RepeatControl);
out.emplace_back(std::move(info));
}
}
static
void writeLimexMasks(const build_info &args, implNFA_t *limex) {
const NGHolder &h = args.h;
// Init masks.
u32 s_i = args.state_ids.at(h.start);
u32 sds_i = args.state_ids.at(h.startDs);
// cppcheck-suppress knownConditionTrueFalse
if (s_i != NO_STATE) {
maskSetBit(limex->init, s_i);
if (is_triggered(h)) {
maskSetBit(limex->initDS, s_i);
}
}
// cppcheck-suppress knownConditionTrueFalse
if (sds_i != NO_STATE) {
maskSetBit(limex->init, sds_i);
maskSetBit(limex->initDS, sds_i);
}
// Zombie mask.
for (auto v : args.zombies) {
u32 state_id = args.state_ids.at(v);
assert(state_id != NO_STATE);
maskSetBit(limex->zombieMask, state_id);
}
// Repeat cyclic mask.
for (const auto &br : args.repeats) {
u32 cyclic = args.state_ids.at(br.cyclic);
assert(cyclic != NO_STATE);
maskSetBit(limex->repeatCyclicMask, cyclic);
}
/* also include tugs in repeat cyclic mask */
for (size_t i = args.tugs.find_first(); i != args.tugs.npos;
i = args.tugs.find_next(i)) {
maskSetBit(limex->repeatCyclicMask, i);
}
}
static
void writeShiftMasks(const build_info &args, implNFA_t *limex) {
const NGHolder &h = args.h;
u32 maxShift = findMaxVarShift(args, limex->shiftCount);
u32 shiftMask = 0;
int shiftMaskIdx = 0;
for (const auto &e : edges_range(h)) {
u32 from = args.state_ids.at(source(e, h));
u32 to = args.state_ids.at(target(e, h));
// cppcheck-suppress knownConditionTrueFalse
if (from == NO_STATE || to == NO_STATE) {
continue;
}
// We check for exceptional transitions here, as we don't want tug
// trigger transitions emitted as limited transitions (even if they
// could be in this model).
if (!isExceptionalTransition(from, to, args, maxShift)) {
u32 shift = to - from;
if ((shiftMask & (1UL << shift)) == 0UL) {
shiftMask |= (1UL << shift);
limex->shiftAmount[shiftMaskIdx++] = (u8)shift;
}
assert(limex->shiftCount <= MAX_SHIFT_COUNT);
for (u32 i = 0; i < limex->shiftCount; i++) {
if (limex->shiftAmount[i] == (u8)shift) {
maskSetBit(limex->shift[i], from);
break;
}
}
}
}
if (maxShift && limex->shiftCount > 1) {
for (u32 i = 0; i < limex->shiftCount; i++) {
assert(!isMaskZero(limex->shift[i]));
}
}
}
static
void findExceptionalTransitions(const build_info &args,
unordered_set<NFAEdge> &exceptional,
u32 maxShift) {
const NGHolder &h = args.h;
for (const auto &e : edges_range(h)) {
u32 from = args.state_ids.at(source(e, h));
u32 to = args.state_ids.at(target(e, h));
// cppcheck-suppress knownConditionTrueFalse
if (from == NO_STATE || to == NO_STATE) {
continue;
}
if (isExceptionalTransition(from, to, args, maxShift)) {
exceptional.insert(e);
}
}
}
static
void writeExceptions(const build_info &args,
const map<ExceptionProto, vector<u32>> &exceptionMap,
const vector<u32> &repeatOffsets, implNFA_t *limex,
const u32 exceptionsOffset,
const u32 reportListOffset) {
DEBUG_PRINTF("exceptionsOffset=%u\n", exceptionsOffset);
exception_t *etable = reinterpret_cast<exception_t *>(reinterpret_cast<char *>(limex) + exceptionsOffset);
assert(ISALIGNED(etable));
map<u32, ExceptionProto> exception_by_state;
for (const auto &m : exceptionMap) {
const ExceptionProto &proto = m.first;
const vector<u32> &states = m.second;
for (u32 i : states) {
assert(!contains(exception_by_state, i));
exception_by_state.emplace(i, proto);
}
}
u32 ecount = 0;
for (const auto &m : exception_by_state) {
const ExceptionProto &proto = m.second;
u32 state_id = m.first;
DEBUG_PRINTF("exception %u, triggered by state %u\n", ecount,
state_id);
// Write the exception entry.
exception_t &e = etable[ecount];
maskSetBits(e.squash, proto.squash_states);
maskSetBits(e.successors, proto.succ_states);
if (proto.reports_index == MO_INVALID_IDX) {
e.reports = MO_INVALID_IDX;
} else {
e.reports = reportListOffset +
proto.reports_index * sizeof(ReportID);
}
e.hasSquash = verify_u8(proto.squash);
e.trigger = verify_u8(proto.trigger);
u32 repeat_offset = proto.repeat_index == MO_INVALID_IDX
? MO_INVALID_IDX
: repeatOffsets[proto.repeat_index];
e.repeatOffset = repeat_offset;
// for the state that can switch it on
// set this bit in the exception mask
maskSetBit(limex->exceptionMask, state_id);
ecount++;
}
limex->exceptionOffset = exceptionsOffset;
limex->exceptionCount = ecount;
if (args.num_states > 64 && args.cc.target_info.has_avx512vbmi()) {
const u8 *exceptionMask = reinterpret_cast<const u8 *>(&limex->exceptionMask);
u8 *shufMask = reinterpret_cast<u8 *>(&limex->exceptionShufMask);
u8 *bitMask = reinterpret_cast<u8 *>(&limex->exceptionBitMask);
u8 *andMask = reinterpret_cast<u8 *>(&limex->exceptionAndMask);
u32 tot_cnt = 0;
u32 pos = 0;
bool valid = true;
size_t tot = sizeof(limex->exceptionMask);
size_t base = 0;
// We normally have up to 64 exceptions to handle,
// but treat 384 state Limex differently to simplify operations
size_t limit = 64;
if (args.num_states > 256 && args.num_states <= 384) {
limit = 48;
}
for (size_t i = 0; i < tot; i++) {
if (!exceptionMask[i]) {
continue;
}
u32 bit_cnt = popcount32(exceptionMask[i]);
tot_cnt += bit_cnt;
if (tot_cnt > limit) {
valid = false;
break;
}
u32 emsk = exceptionMask[i];
while (emsk) {
u32 t = findAndClearLSB_32(&emsk);
bitMask[pos] = 1U << t;
andMask[pos] = 1U << t;
shufMask[pos++] = i + base;
if (pos == 32 &&
(args.num_states > 128 && args.num_states <= 256)) {
base += 32;
}
}
}
// Avoid matching unused bytes
for (u32 i = pos; i < 64; i++) {
bitMask[i] = 0xff;
}
if (valid) {
setLimexFlag(limex, LIMEX_FLAG_EXTRACT_EXP);
}
}
}
static
void writeReachMapping(const vector<NFAStateSet> &reach,
const vector<u8> &reachMap, implNFA_t *limex,
const u32 reachOffset) {
DEBUG_PRINTF("reachOffset=%u\n", reachOffset);
// Reach mapping is inside the LimEx structure.
copy(reachMap.begin(), reachMap.end(), &limex->reachMap[0]);
// Reach table is right after the LimEx structure.
tableRow_t *reachMask = reinterpret_cast<tableRow_t *>(reinterpret_cast<char *>(limex) + reachOffset);
assert(ISALIGNED(reachMask));
for (size_t i = 0, end = reach.size(); i < end; i++) {
maskSetBits(reachMask[i], reach[i]);
}
limex->reachSize = verify_u32(reach.size());
}
static
void writeTopMasks(const vector<NFAStateSet> &tops, implNFA_t *limex,
const u32 topsOffset) {
DEBUG_PRINTF("topsOffset=%u\n", topsOffset);
limex->topOffset = topsOffset;
tableRow_t *topMasks = reinterpret_cast<tableRow_t *>(reinterpret_cast<char *>(limex) + topsOffset);
assert(ISALIGNED(topMasks));
for (size_t i = 0, end = tops.size(); i < end; i++) {
maskSetBits(topMasks[i], tops[i]);
}
limex->topCount = verify_u32(tops.size());
}
static
void writeAccelSsse3Masks(const NFAStateSet &accelMask, implNFA_t *limex) {
char *perm_base = reinterpret_cast<char *>(&limex->accelPermute);
char *comp_base = reinterpret_cast<char *>(&limex->accelCompare);
u32 num = 0; // index in accel table.
for (size_t i = accelMask.find_first(); i != accelMask.npos;
i = accelMask.find_next(i), ++num) {
u32 state_id = verify_u32(i);
DEBUG_PRINTF("accel num=%u, state=%u\n", num, state_id);
// PSHUFB permute and compare masks
size_t mask_idx = sizeof(u_128) * (state_id / 128U);
DEBUG_PRINTF("mask_idx=%zu\n", mask_idx);
u_128 *perm = reinterpret_cast<u_128 *>(perm_base + mask_idx);
u_128 *comp = reinterpret_cast<u_128 *>(comp_base + mask_idx);
maskSetByte(*perm, num, ((state_id % 128U) / 8U));
maskSetByte(*comp, num, ~(1U << (state_id % 8U)));
}
}
static
void writeAccel(const NFAStateSet &accelMask,
const NFAStateSet &accelFriendsMask,
const AccelAuxVector &accelAux,
const vector<u8> &accelTable, implNFA_t *limex,
const u32 accelTableOffset, const u32 accelAuxOffset) {
DEBUG_PRINTF("accelTableOffset=%u, accelAuxOffset=%u\n",
accelTableOffset, accelAuxOffset);
// Write accel lookup table.
limex->accelTableOffset = accelTableOffset;
copy(accelTable.begin(), accelTable.end(),
reinterpret_cast<u8 *>(reinterpret_cast<char *>(limex) + accelTableOffset));
// Write accel aux structures.
limex->accelAuxOffset = accelAuxOffset;
AccelAux *auxTable = reinterpret_cast<AccelAux *>(reinterpret_cast<char *>(limex) + accelAuxOffset);
assert(ISALIGNED(auxTable));
copy(accelAux.begin(), accelAux.end(), auxTable);
// Write LimEx structure members.
limex->accelCount = verify_u32(accelTable.size());
// FIXME: accelAuxCount is unused?
limex->accelAuxCount = verify_u32(accelAux.size());
// Write LimEx masks.
maskSetBits(limex->accel, accelMask);
maskSetBits(limex->accel_and_friends, accelFriendsMask);
// We can use PSHUFB-based shuffles for models >= 128 states. These
// require some additional masks in the bytecode.
maskClear(limex->accelCompare);
maskFill(limex->accelPermute, (char)0x80);
if (NFATraits<dtype>::maxStates >= 128) {
writeAccelSsse3Masks(accelMask, limex);
}
}
static
void writeAccepts(const NFAStateSet &acceptMask,
const NFAStateSet &acceptEodMask,
const vector<NFAAccept> &accepts,
const vector<NFAAccept> &acceptsEod,
const vector<NFAStateSet> &squash, implNFA_t *limex,
const u32 acceptsOffset, const u32 acceptsEodOffset,
const u32 squashOffset, const u32 reportListOffset) {
char *limex_base = reinterpret_cast<char *>(limex);
DEBUG_PRINTF("acceptsOffset=%u, acceptsEodOffset=%u, squashOffset=%u\n",
acceptsOffset, acceptsEodOffset, squashOffset);
// LimEx masks (in structure)
maskSetBits(limex->accept, acceptMask);
maskSetBits(limex->acceptAtEOD, acceptEodMask);
// Transforms the indices (report list, squash mask) into offsets
// relative to the base of the limex.
auto transform_offset_fn = [&](NFAAccept a) {
if (!a.single_report) {
a.reports = reportListOffset + a.reports * sizeof(ReportID);
}
a.squash = squashOffset + a.squash * sizeof(tableRow_t);
return a;
};
// Write accept table.
limex->acceptOffset = acceptsOffset;
limex->acceptCount = verify_u32(accepts.size());
DEBUG_PRINTF("NFA has %zu accepts\n", accepts.size());
NFAAccept *acceptsTable = reinterpret_cast<NFAAccept *>(limex_base + acceptsOffset);
assert(ISALIGNED(acceptsTable));
transform(accepts.begin(), accepts.end(), acceptsTable,
transform_offset_fn);
// Write eod accept table.
limex->acceptEodOffset = acceptsEodOffset;
limex->acceptEodCount = verify_u32(acceptsEod.size());
DEBUG_PRINTF("NFA has %zu EOD accepts\n", acceptsEod.size());
NFAAccept *acceptsEodTable = reinterpret_cast<NFAAccept *>(limex_base + acceptsEodOffset);
assert(ISALIGNED(acceptsEodTable));
transform(acceptsEod.begin(), acceptsEod.end(), acceptsEodTable,
transform_offset_fn);
// Write squash mask table.
limex->squashCount = verify_u32(squash.size());
limex->squashOffset = squashOffset;
DEBUG_PRINTF("NFA has %zu report squash masks\n", squash.size());
tableRow_t *mask = reinterpret_cast<tableRow_t *>(limex_base + squashOffset);
assert(ISALIGNED(mask));
for (size_t i = 0, end = squash.size(); i < end; i++) {
maskSetBits(mask[i], squash[i]);
}
}
static
void writeRepeats(const vector<bytecode_ptr<NFARepeatInfo>> &repeats,
vector<u32> &repeatOffsets, implNFA_t *limex,
const u32 repeatOffsetsOffset, const u32 repeatOffset) {
const u32 num_repeats = verify_u32(repeats.size());
DEBUG_PRINTF("repeatOffsetsOffset=%u, repeatOffset=%u\n",
repeatOffsetsOffset, repeatOffset);
repeatOffsets.resize(num_repeats);
u32 offset = repeatOffset;
for (u32 i = 0; i < num_repeats; i++) {
repeatOffsets[i] = offset;
assert(repeats[i]);
memcpy(reinterpret_cast<char *>(limex) + offset, repeats[i].get(), repeats[i].size());
offset += repeats[i].size();
}
// Write repeat offset lookup table.
assert(ISALIGNED_N(reinterpret_cast<char *>(limex) + repeatOffsetsOffset, alignof(u32)));
copy_bytes(reinterpret_cast<char *>(limex) + repeatOffsetsOffset, repeatOffsets);
limex->repeatOffset = repeatOffsetsOffset;
limex->repeatCount = num_repeats;
}
static
void writeReportList(const vector<ReportID> &reports, implNFA_t *limex,
const u32 reportListOffset) {
DEBUG_PRINTF("reportListOffset=%u\n", reportListOffset);
assert(ISALIGNED_N(reinterpret_cast<char *>(limex) + reportListOffset,
alignof(ReportID)));
copy_bytes(reinterpret_cast<char *>(limex) + reportListOffset, reports);
}
static
bytecode_ptr<NFA> generateNfa(const build_info &args) {
if (args.num_states > NFATraits<dtype>::maxStates) {
return bytecode_ptr<NFA>(nullptr);
}
// Build bounded repeat structures.
vector<bytecode_ptr<NFARepeatInfo>> repeats;
u32 repeats_full_state = 0;
u32 repeats_stream_state = 0;
buildRepeats(args, repeats, &repeats_full_state, &repeats_stream_state);
size_t repeatSize = 0;
for (size_t i = 0; i < repeats.size(); i++) {
repeatSize += repeats[i].size();
}
// We track report lists that have already been written into the global
// list in case we can reuse them.
ReportListCache reports_cache;
unordered_set<NFAEdge> exceptional;
u32 shiftCount = findBestNumOfVarShifts(args);
assert(shiftCount);
u32 maxShift = findMaxVarShift(args, shiftCount);
findExceptionalTransitions(args, exceptional, maxShift);
map<ExceptionProto, vector<u32>> exceptionMap;
vector<ReportID> reportList;
u32 exceptionCount = buildExceptionMap(args, reports_cache, exceptional,
exceptionMap, reportList);
assert(exceptionCount <= args.num_states);
// Build reach table and character mapping.
vector<NFAStateSet> reach;
vector<u8> reachMap;
buildReachMapping(args, reach, reachMap);
// Build top masks.
vector<NFAStateSet> tops;
buildTopMasks(args, tops);
// Build all our accept info.
NFAStateSet acceptMask, acceptEodMask;
vector<NFAAccept> accepts, acceptsEod;
vector<NFAStateSet> squash;
buildAccepts(args, reports_cache, acceptMask, acceptEodMask, accepts,
acceptsEod, reportList, squash);
// Build all our accel info.
NFAStateSet accelMask, accelFriendsMask;
AccelAuxVector accelAux;
vector<u8> accelTable;
buildAccel(args, accelMask, accelFriendsMask, accelAux, accelTable);
// Compute the offsets in the bytecode for this LimEx NFA for all of
// our structures. First, the NFA and LimEx structures. All other
// offsets are relative to the start of the LimEx struct, starting with
// the reach table.
u32 offset = sizeof(implNFA_t);
const u32 reachOffset = offset;
offset += sizeof(tableRow_t) * reach.size();
const u32 topsOffset = offset;
offset += sizeof(tableRow_t) * tops.size();
const u32 accelTableOffset = offset;
offset += sizeof(u8) * accelTable.size();
offset = ROUNDUP_N(offset, alignof(AccelAux));
const u32 accelAuxOffset = offset;
offset += sizeof(AccelAux) * accelAux.size();
offset = ROUNDUP_N(offset, alignof(NFAAccept));
const u32 acceptsOffset = offset;
offset += sizeof(NFAAccept) * accepts.size();
const u32 acceptsEodOffset = offset;
offset += sizeof(NFAAccept) * acceptsEod.size();
offset = ROUNDUP_CL(offset);
const u32 squashOffset = offset;
offset += sizeof(tableRow_t) * squash.size();
offset = ROUNDUP_CL(offset);
const u32 exceptionsOffset = offset;
offset += sizeof(exception_t) * exceptionCount;
const u32 reportListOffset = offset;
offset += sizeof(ReportID) * reportList.size();
const u32 repeatOffsetsOffset = offset;
offset += sizeof(u32) * args.repeats.size();
offset = ROUNDUP_CL(offset);
const u32 repeatsOffset = offset;
offset += repeatSize;
// Now we can allocate space for the NFA and get to work on layout.
size_t nfaSize = sizeof(NFA) + offset;
DEBUG_PRINTF("nfa size %zu\n", nfaSize);
auto nfa = make_zeroed_bytecode_ptr<NFA>(nfaSize);
assert(nfa); // otherwise we would have thrown std::bad_alloc
implNFA_t *limex = reinterpret_cast<implNFA_t *>(getMutableImplNfa(nfa.get()));
assert(ISALIGNED(limex));
writeReachMapping(reach, reachMap, limex, reachOffset);
writeTopMasks(tops, limex, topsOffset);
writeAccel(accelMask, accelFriendsMask, accelAux, accelTable,
limex, accelTableOffset, accelAuxOffset);
writeAccepts(acceptMask, acceptEodMask, accepts, acceptsEod, squash,
limex, acceptsOffset, acceptsEodOffset, squashOffset,
reportListOffset);
limex->shiftCount = shiftCount;
writeShiftMasks(args, limex);
if (cannotDie(args)) {
DEBUG_PRINTF("nfa cannot die\n");
setLimexFlag(limex, LIMEX_FLAG_CANNOT_DIE);
}
// Determine the state required for our state vector.
findStateSize(args, limex);
writeReportList(reportList, limex, reportListOffset);
// Repeat structures and offset table.
vector<u32> repeatOffsets;
writeRepeats(repeats, repeatOffsets, limex, repeatOffsetsOffset,
repeatsOffset);
writeExceptions(args, exceptionMap, repeatOffsets, limex, exceptionsOffset,
reportListOffset);
writeLimexMasks(args, limex);
allocState(nfa.get(), repeats_full_state, repeats_stream_state);
nfa->type = dtype;
nfa->length = verify_u32(nfaSize);
nfa->nPositions = args.num_states;
if (!args.zombies.empty()) {
setNfaFlag(nfa.get(), NFA_ZOMBIE);
}
if (!acceptsEod.empty()) {
setNfaFlag(nfa.get(), NFA_ACCEPTS_EOD);
}
return nfa;
}
static int score(const build_info &args) {
// LimEx NFAs are available in sizes from 32 to 512-bit.
size_t num_states = args.num_states;
size_t sz = findContainerSize(num_states);
if (sz < 32) {
sz = 32;
}
if (args.cc.grey.nfaForceSize) {
sz = args.cc.grey.nfaForceSize;
}
if (sz != NFATraits<dtype>::maxStates) {
return -1; // fail, size not appropriate
}
// We are of the right size, calculate a score based on the number
// of exceptions and the number of shifts used by this LimEx.
int score;
u32 shiftCount = findBestNumOfVarShifts(args, &score);
if (shiftCount == 0) {
return -1;
}
return score;
}
};
template<NFAEngineType dtype>
struct generateNfa {
static bytecode_ptr<NFA> call(const build_info &args) {
return Factory<dtype>::generateNfa(args);
}
};
template<NFAEngineType dtype>
struct scoreNfa {
static int call(const build_info &args) {
return Factory<dtype>::score(args);
}
};
#define MAKE_LIMEX_TRAITS(mlt_size) \
template<> struct NFATraits<LIMEX_NFA_##mlt_size> { \
typedef LimExNFA##mlt_size implNFA_t; \
typedef u_##mlt_size tableRow_t; \
typedef NFAException##mlt_size exception_t; \
static const size_t maxStates = mlt_size; \
static const size_t scratch_state_size = mlt_size == 64 ? sizeof(m128) \
: sizeof(tableRow_t); \
};
MAKE_LIMEX_TRAITS(32)
MAKE_LIMEX_TRAITS(64)
MAKE_LIMEX_TRAITS(128)
MAKE_LIMEX_TRAITS(256)
MAKE_LIMEX_TRAITS(384)
MAKE_LIMEX_TRAITS(512)
} // namespace
#ifndef NDEBUG
// Some sanity tests, called by an assertion in generate().
static UNUSED
bool isSane(const NGHolder &h, const map<u32, set<NFAVertex>> &tops,
const unordered_map<NFAVertex, u32> &state_ids,
u32 num_states) {
unordered_set<u32> seen;
unordered_set<NFAVertex> top_starts;
for (const auto &vv : tops | map_values) {
insert(&top_starts, vv);
}
for (auto v : vertices_range(h)) {
if (!contains(state_ids, v)) {
DEBUG_PRINTF("no entry for vertex %zu in state map\n", h[v].index);
return false;
}
const u32 i = state_ids.at(v);
// cppcheck-suppress knownConditionTrueFalse
if (i == NO_STATE) {
continue;
}
DEBUG_PRINTF("checking vertex %zu (state %u)\n", h[v].index, i);
if (i >= num_states || contains(seen, i)) {
DEBUG_PRINTF("vertex %u/%u has invalid state\n", i, num_states);
return false;
}
seen.insert(i);
// All our states should be reachable and have a state assigned.
if (h[v].char_reach.none()) {
DEBUG_PRINTF("vertex %zu has empty reachability\n", h[v].index);
return false;
}
// Every state that isn't a start state (or top, in triggered NFAs)
// must have at least one predecessor that is not itself.
if (v != h.start && v != h.startDs && !contains(top_starts, v)
&& !proper_in_degree(v, h)) {
DEBUG_PRINTF("vertex %zu has no pred\n", h[v].index);
return false;
}
}
if (seen.size() != num_states) {
return false;
}
return true;
}
#endif // NDEBUG
static
bool isFast(const build_info &args) {
const NGHolder &h = args.h;
const u32 num_states = args.num_states;
if (num_states > MAX_SMALL_NFA_STATES) {
return false;
}
unordered_map<NFAVertex, bool> pos_trigger;
for (u32 i = 0; i < args.repeats.size(); i++) {
const BoundedRepeatData &br = args.repeats[i];
assert(!contains(pos_trigger, br.pos_trigger));
pos_trigger[br.pos_trigger] = br.repeatMax <= MAX_REPEAT_SIZE;
}
// Small NFA without bounded repeat should be fast.
if (pos_trigger.empty()) {
return true;
}
vector<NFAVertex> cur;
unordered_set<NFAVertex> visited;
for (const auto &m : args.tops) {
for (NFAVertex v : m.second) {
cur.emplace_back(v);
visited.insert(v);
}
}
u8 pos_dist = 0;
while (!cur.empty()) {
vector<NFAVertex> next;
for (const auto &v : cur) {
if (contains(pos_trigger, v)) {
const CharReach &cr = h[v].char_reach;
if (!pos_trigger[v] && cr.count() > MAX_REPEAT_CHAR_REACH) {
return false;
}
}
for (const auto &w : adjacent_vertices_range(v, h)) {
if (w == v) {
continue;
}
u32 j = args.state_ids.at(w);
// cppcheck-suppress knownConditionTrueFalse
if (j == NO_STATE) {
continue;
}
if (!contains(visited, w)) {
next.emplace_back(w);
visited.insert(w);
}
}
}
if (++pos_dist >= MIN_REPEAT_TRIGGER_DISTANCE) {
break;
}
swap(cur, next);
}
return true;
}
static
u32 max_state(const unordered_map<NFAVertex, u32> &state_ids) {
u32 rv = 0;
for (const auto &m : state_ids) {
DEBUG_PRINTF("state %u\n", m.second);
if (m.second != NO_STATE) {
rv = max(m.second, rv);
}
}
DEBUG_PRINTF("max %u\n", rv);
return rv;
}
bytecode_ptr<NFA> generate(NGHolder &h,
const unordered_map<NFAVertex, u32> &states,
const vector<BoundedRepeatData> &repeats,
const unordered_map<NFAVertex, NFAStateSet> &reportSquashMap,
const unordered_map<NFAVertex, NFAStateSet> &squashMap,
const map<u32, set<NFAVertex>> &tops,
const set<NFAVertex> &zombies, bool do_accel,
bool stateCompression, bool &fast, u32 hint,
const CompileContext &cc) {
const u32 num_states = max_state(states) + 1;
DEBUG_PRINTF("total states: %u\n", num_states);
if (!cc.grey.allowLimExNFA) {
DEBUG_PRINTF("limex not allowed\n");
return bytecode_ptr<NFA>(nullptr);
}
// If you ask for a particular type, it had better be an NFA.
assert(hint == INVALID_NFA || hint <= LAST_LIMEX_NFA);
DEBUG_PRINTF("hint=%u\n", hint);
// Sanity check the input data.
assert(isSane(h, tops, states, num_states));
// Build arguments used in the rest of this file.
build_info arg(h, states, repeats, reportSquashMap, squashMap, tops,
zombies, do_accel, stateCompression, cc, num_states);
// Acceleration analysis.
fillAccelInfo(arg);
vector<pair<int, NFAEngineType>> scores;
if (hint != INVALID_NFA) {
// The caller has told us what to (attempt to) build.
scores.emplace_back(0, (NFAEngineType)hint);
} else {
for (size_t i = 0; i <= LAST_LIMEX_NFA; i++) {
NFAEngineType ntype = (NFAEngineType)i;
int score = DISPATCH_BY_LIMEX_TYPE(ntype, scoreNfa, arg);
if (score >= 0) {
DEBUG_PRINTF("%s scores %d\n", nfa_type_name(ntype), score);
scores.emplace_back(score, ntype);
}
}
}
if (scores.empty()) {
DEBUG_PRINTF("No NFA returned a valid score for this case.\n");
return bytecode_ptr<NFA>(nullptr);
}
// Sort acceptable models in priority order, lowest score first.
sort(scores.begin(), scores.end());
for (const auto &elem : scores) {
assert(elem.first >= 0);
NFAEngineType limex_model = elem.second;
auto nfa = DISPATCH_BY_LIMEX_TYPE(limex_model, generateNfa, arg);
if (nfa) {
DEBUG_PRINTF("successful build with NFA engine: %s\n",
nfa_type_name(limex_model));
fast = isFast(arg);
return nfa;
}
}
DEBUG_PRINTF("NFA build failed.\n");
return bytecode_ptr<NFA>(nullptr);
}
u32 countAccelStates(NGHolder &h,
const unordered_map<NFAVertex, u32> &states,
const vector<BoundedRepeatData> &repeats,
const unordered_map<NFAVertex, NFAStateSet> &reportSquashMap,
const unordered_map<NFAVertex, NFAStateSet> &squashMap,
const map<u32, set<NFAVertex>> &tops,
const set<NFAVertex> &zombies,
const CompileContext &cc) {
const u32 num_states = max_state(states) + 1;
DEBUG_PRINTF("total states: %u\n", num_states);
if (!cc.grey.allowLimExNFA) {
DEBUG_PRINTF("limex not allowed\n");
return 0;
}
// Sanity check the input data.
assert(isSane(h, tops, states, num_states));
const bool do_accel = true;
const bool state_compression = false;
// Build arguments used in the rest of this file.
build_info bi(h, states, repeats, reportSquashMap, squashMap, tops, zombies,
do_accel, state_compression, cc, num_states);
// Acceleration analysis.
nfaFindAccelSchemes(bi.h, bi.br_cyclic, &bi.accel.accel_map);
u32 num_accel = verify_u32(bi.accel.accel_map.size());
DEBUG_PRINTF("found %u accel states\n", num_accel);
return num_accel;
}
} // namespace ue2
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