1/*
2 * Copyright (c) 2015-2017, Intel Corporation
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * * Redistributions of source code must retain the above copyright notice,
8 * this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of Intel Corporation nor the names of its contributors
13 * may be used to endorse or promote products derived from this software
14 * without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include "accel.h"
30#include "accelcompile.h"
31#include "shufticompile.h"
32#include "trufflecompile.h"
33#include "nfagraph/ng_limex_accel.h" /* for constants */
34#include "util/bitutils.h"
35#include "util/verify_types.h"
36
37#include <map>
38#include <set>
39#include <vector>
40
41using namespace std;
42
43namespace ue2 {
44
45static
46void buildAccelSingle(const AccelInfo &info, AccelAux *aux) {
47 assert(aux->accel_type == ACCEL_NONE);
48 if (info.single_stops.all()) {
49 return;
50 }
51
52 size_t outs = info.single_stops.count();
53 DEBUG_PRINTF("%zu outs\n", outs);
54 assert(outs && outs < 256);
55 u32 offset = info.single_offset;
56
57 if (outs == 1) {
58 aux->accel_type = ACCEL_VERM;
59 aux->verm.offset = offset;
60 aux->verm.c = info.single_stops.find_first();
61 DEBUG_PRINTF("building vermicelli caseful for 0x%02hhx\n", aux->verm.c);
62 return;
63 }
64
65 if (outs == 2 && info.single_stops.isCaselessChar()) {
66 aux->accel_type = ACCEL_VERM_NOCASE;
67 aux->verm.offset = offset;
68 aux->verm.c = info.single_stops.find_first() & CASE_CLEAR;
69 DEBUG_PRINTF("building vermicelli caseless for 0x%02hhx\n",
70 aux->verm.c);
71 return;
72 }
73
74 DEBUG_PRINTF("attempting shufti for %zu chars\n", outs);
75 if (-1 != shuftiBuildMasks(info.single_stops, (u8 *)&aux->shufti.lo,
76 (u8 *)&aux->shufti.hi)) {
77 aux->accel_type = ACCEL_SHUFTI;
78 aux->shufti.offset = offset;
79 DEBUG_PRINTF("shufti built OK\n");
80 return;
81 } else {
82 DEBUG_PRINTF("shufti build failed, falling through\n");
83 }
84
85 if (outs <= ACCEL_MAX_STOP_CHAR) {
86 DEBUG_PRINTF("building Truffle for %zu chars\n", outs);
87 aux->accel_type = ACCEL_TRUFFLE;
88 aux->truffle.offset = offset;
89 truffleBuildMasks(info.single_stops, (u8 *)&aux->truffle.mask1,
90 (u8 *)&aux->truffle.mask2);
91 return;
92 }
93
94 DEBUG_PRINTF("unable to accelerate case with %zu outs\n", outs);
95}
96
97bool buildDvermMask(const flat_set<pair<u8, u8>> &escape_set, u8 *m1_out,
98 u8 *m2_out) {
99 u8 a1 = 0xff;
100 u8 a2 = 0xff;
101 u8 b1 = 0xff;
102 u8 b2 = 0xff;
103
104 for (const auto &e : escape_set) {
105 DEBUG_PRINTF("%0hhx %0hhx\n", e.first, e.second);
106 a1 &= e.first;
107 b1 &= ~e.first;
108 a2 &= e.second;
109 b2 &= ~e.second;
110 }
111
112 u8 m1 = a1 | b1;
113 u8 m2 = a2 | b2;
114
115 u32 holes1 = 8 - popcount32(m1);
116 u32 holes2 = 8 - popcount32(m2);
117
118 DEBUG_PRINTF("aaaa %0hhx %0hhx\n", a1, a2);
119 DEBUG_PRINTF("bbbb %0hhx %0hhx\n", b1, b2);
120 DEBUG_PRINTF("mask %0hhx %0hhx\n", m1, m2);
121
122 assert(holes1 <= 8 && holes2 <= 8);
123 assert(escape_set.size() <= 1U << (holes1 + holes2));
124 if (escape_set.size() != 1U << (holes1 + holes2)) {
125 return false;
126 }
127
128 if (m1_out) {
129 *m1_out = m1;
130 }
131 if (m2_out) {
132 *m2_out = m2;
133 }
134
135 return true;
136}
137
138static
139bool isCaselessDouble(const flat_set<pair<u8, u8>> &stop) {
140 // test for vector containing <A,Z> <A,z> <a,Z> <a,z>
141 if (stop.size() != 4) {
142 return false;
143 }
144 const u8 a = stop.begin()->first & CASE_CLEAR;
145 const u8 b = stop.begin()->second & CASE_CLEAR;
146
147 flat_set<pair<u8, u8>>::const_iterator it, ite;
148 for (it = stop.begin(), ite = stop.end(); it != ite; ++it) {
149 if ((it->first & CASE_CLEAR) != a || (it->second & CASE_CLEAR) != b) {
150 return false;
151 }
152 }
153
154 return true;
155}
156
157static
158void buildAccelDouble(const AccelInfo &info, AccelAux *aux) {
159 size_t outs1 = info.double_stop1.count();
160 size_t outs2 = info.double_stop2.size();
161
162 u8 offset = verify_u8(info.double_offset);
163 DEBUG_PRINTF("outs1=%zu, outs2=%zu\n", outs1, outs2);
164
165 assert(aux->accel_type == ACCEL_NONE);
166
167 if (!outs2) {
168 /* no double byte accel available */
169 return;
170 }
171
172 // double-byte accel
173 if (outs1 == 0 && outs2 == 1) {
174 aux->accel_type = ACCEL_DVERM;
175 aux->dverm.offset = offset;
176 aux->dverm.c1 = info.double_stop2.begin()->first;
177 aux->dverm.c2 = info.double_stop2.begin()->second;
178 DEBUG_PRINTF("building double-vermicelli caseful for 0x%02hhx%02hhx\n",
179 aux->dverm.c1, aux->dverm.c2);
180 return;
181 }
182
183 if (outs1 == 0 && isCaselessDouble(info.double_stop2)) {
184 aux->accel_type = ACCEL_DVERM_NOCASE;
185 aux->dverm.offset = offset;
186 aux->dverm.c1 = info.double_stop2.begin()->first & CASE_CLEAR;
187 aux->dverm.c2 = info.double_stop2.begin()->second & CASE_CLEAR;
188 DEBUG_PRINTF("building double-vermicelli caseless for 0x%02hhx%02hhx\n",
189 aux->dverm.c1, aux->dverm.c2);
190 return;
191 }
192
193 if (outs1 == 0) {
194 u8 m1;
195 u8 m2;
196
197 if (buildDvermMask(info.double_stop2, &m1, &m2)) {
198 aux->accel_type = ACCEL_DVERM_MASKED;
199 aux->dverm.offset = offset;
200 aux->dverm.c1 = info.double_stop2.begin()->first & m1;
201 aux->dverm.c2 = info.double_stop2.begin()->second & m2;
202 aux->dverm.m1 = m1;
203 aux->dverm.m2 = m2;
204 DEBUG_PRINTF("building maskeddouble-vermicelli for 0x%02hhx%02hhx\n",
205 aux->dverm.c1, aux->dverm.c2);
206 return;
207 }
208 }
209
210 if (outs1 < outs2 && outs1 <= 2) { // Heuristic from UE-438.
211 DEBUG_PRINTF("building double-shufti for %zu one-byte and %zu"
212 " two-byte literals\n", outs1, outs2);
213 aux->accel_type = ACCEL_DSHUFTI;
214 aux->dshufti.offset = offset;
215 if (shuftiBuildDoubleMasks(
216 info.double_stop1, info.double_stop2, (u8 *)&aux->dshufti.lo1,
217 (u8 *)&aux->dshufti.hi1, (u8 *)&aux->dshufti.lo2,
218 (u8 *)&aux->dshufti.hi2)) {
219 return;
220 }
221 }
222
223 // drop back to attempt single-byte accel
224 DEBUG_PRINTF("dropping back to single-byte acceleration\n");
225 aux->accel_type = ACCEL_NONE;
226}
227
228bool buildAccelAux(const AccelInfo &info, AccelAux *aux) {
229 assert(aux->accel_type == ACCEL_NONE);
230 if (info.single_stops.none()) {
231 DEBUG_PRINTF("picked red tape\n");
232 aux->accel_type = ACCEL_RED_TAPE;
233 aux->generic.offset = info.single_offset;
234 }
235 if (aux->accel_type == ACCEL_NONE) {
236 buildAccelDouble(info, aux);
237 }
238 if (aux->accel_type == ACCEL_NONE) {
239 buildAccelSingle(info, aux);
240 }
241
242 assert(aux->accel_type == ACCEL_NONE
243 || aux->generic.offset == info.single_offset
244 || aux->generic.offset == info.double_offset);
245 return aux->accel_type != ACCEL_NONE;
246}
247
248} // namespace ue2
249