1 /*
2 +----------------------------------------------------------------------+
3 | Zend Engine, DFG - Data Flow Graph |
4 +----------------------------------------------------------------------+
5 | Copyright (c) The PHP Group |
6 +----------------------------------------------------------------------+
7 | This source file is subject to version 3.01 of the PHP license, |
8 | that is bundled with this package in the file LICENSE, and is |
9 | available through the world-wide-web at the following url: |
10 | https://www.php.net/license/3_01.txt |
11 | If you did not receive a copy of the PHP license and are unable to |
12 | obtain it through the world-wide-web, please send a note to |
13 | license@php.net so we can mail you a copy immediately. |
14 +----------------------------------------------------------------------+
15 | Authors: Dmitry Stogov <dmitry@php.net> |
16 +----------------------------------------------------------------------+
17 */
18
19 #include "zend_compile.h"
20 #include "zend_dfg.h"
21
_zend_dfg_add_use_def_op(const zend_op_array * op_array,const zend_op * opline,uint32_t build_flags,zend_bitset use,zend_bitset def)22 static zend_always_inline void _zend_dfg_add_use_def_op(const zend_op_array *op_array, const zend_op *opline, uint32_t build_flags, zend_bitset use, zend_bitset def) /* {{{ */
23 {
24 uint32_t var_num;
25 const zend_op *next;
26
27 if (opline->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
28 var_num = EX_VAR_TO_NUM(opline->op1.var);
29 if (!zend_bitset_in(def, var_num)) {
30 zend_bitset_incl(use, var_num);
31 }
32 }
33 if (((opline->op2_type & (IS_VAR|IS_TMP_VAR)) != 0
34 && opline->opcode != ZEND_FE_FETCH_R
35 && opline->opcode != ZEND_FE_FETCH_RW)
36 || (opline->op2_type == IS_CV)) {
37 var_num = EX_VAR_TO_NUM(opline->op2.var);
38 if (!zend_bitset_in(def, var_num)) {
39 zend_bitset_incl(use, var_num);
40 }
41 }
42 if ((build_flags & ZEND_SSA_USE_CV_RESULTS)
43 && opline->result_type == IS_CV
44 && opline->opcode != ZEND_RECV) {
45 var_num = EX_VAR_TO_NUM(opline->result.var);
46 if (!zend_bitset_in(def, var_num)) {
47 zend_bitset_incl(use, var_num);
48 }
49 }
50
51 switch (opline->opcode) {
52 case ZEND_ASSIGN:
53 if ((build_flags & ZEND_SSA_RC_INFERENCE) && opline->op2_type == IS_CV) {
54 zend_bitset_incl(def, EX_VAR_TO_NUM(opline->op2.var));
55 }
56 if (opline->op1_type == IS_CV) {
57 add_op1_def:
58 zend_bitset_incl(def, EX_VAR_TO_NUM(opline->op1.var));
59 }
60 break;
61 case ZEND_ASSIGN_REF:
62 if (opline->op2_type == IS_CV) {
63 zend_bitset_incl(def, EX_VAR_TO_NUM(opline->op2.var));
64 }
65 if (opline->op1_type == IS_CV) {
66 goto add_op1_def;
67 }
68 break;
69 case ZEND_ASSIGN_DIM:
70 case ZEND_ASSIGN_OBJ:
71 next = opline + 1;
72 if (next->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
73 var_num = EX_VAR_TO_NUM(next->op1.var);
74 if (!zend_bitset_in(def, var_num)) {
75 zend_bitset_incl(use, var_num);
76 }
77 if (build_flags & ZEND_SSA_RC_INFERENCE && next->op1_type == IS_CV) {
78 zend_bitset_incl(def, var_num);
79 }
80 }
81 if (opline->op1_type == IS_CV) {
82 goto add_op1_def;
83 }
84 break;
85 case ZEND_ASSIGN_OBJ_REF:
86 next = opline + 1;
87 if (next->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
88 var_num = EX_VAR_TO_NUM(next->op1.var);
89 if (!zend_bitset_in(def, var_num)) {
90 zend_bitset_incl(use, var_num);
91 }
92 if (next->op1_type == IS_CV) {
93 zend_bitset_incl(def, var_num);
94 }
95 }
96 if (opline->op1_type == IS_CV) {
97 goto add_op1_def;
98 }
99 break;
100 case ZEND_ASSIGN_STATIC_PROP:
101 next = opline + 1;
102 if (next->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
103 var_num = EX_VAR_TO_NUM(next->op1.var);
104 if (!zend_bitset_in(def, var_num)) {
105 zend_bitset_incl(use, var_num);
106 }
107 if ((build_flags & ZEND_SSA_RC_INFERENCE) && next->op1_type == IS_CV) {
108 zend_bitset_incl(def, var_num);
109 }
110 }
111 break;
112 case ZEND_ASSIGN_STATIC_PROP_REF:
113 next = opline + 1;
114 if (next->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
115 var_num = EX_VAR_TO_NUM(next->op1.var);
116 if (!zend_bitset_in(def, var_num)) {
117 zend_bitset_incl(use, var_num);
118 }
119 if (next->op1_type == IS_CV) {
120 zend_bitset_incl(def, var_num);
121 }
122 }
123 break;
124 case ZEND_ASSIGN_STATIC_PROP_OP:
125 next = opline + 1;
126 if (next->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
127 var_num = EX_VAR_TO_NUM(next->op1.var);
128 if (!zend_bitset_in(def, var_num)) {
129 zend_bitset_incl(use, var_num);
130 }
131 }
132 break;
133 case ZEND_ASSIGN_DIM_OP:
134 case ZEND_ASSIGN_OBJ_OP:
135 next = opline + 1;
136 if (next->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
137 var_num = EX_VAR_TO_NUM(next->op1.var);
138 if (!zend_bitset_in(def, var_num)) {
139 zend_bitset_incl(use, var_num);
140 }
141 }
142 if (opline->op1_type == IS_CV) {
143 goto add_op1_def;
144 }
145 break;
146 case ZEND_ASSIGN_OP:
147 case ZEND_PRE_INC:
148 case ZEND_PRE_DEC:
149 case ZEND_POST_INC:
150 case ZEND_POST_DEC:
151 case ZEND_BIND_GLOBAL:
152 case ZEND_BIND_STATIC:
153 case ZEND_SEND_VAR_NO_REF:
154 case ZEND_SEND_VAR_NO_REF_EX:
155 case ZEND_SEND_VAR_EX:
156 case ZEND_SEND_FUNC_ARG:
157 case ZEND_SEND_REF:
158 case ZEND_SEND_UNPACK:
159 case ZEND_FE_RESET_RW:
160 case ZEND_MAKE_REF:
161 case ZEND_PRE_INC_OBJ:
162 case ZEND_PRE_DEC_OBJ:
163 case ZEND_POST_INC_OBJ:
164 case ZEND_POST_DEC_OBJ:
165 case ZEND_UNSET_DIM:
166 case ZEND_UNSET_OBJ:
167 case ZEND_FETCH_DIM_W:
168 case ZEND_FETCH_DIM_RW:
169 case ZEND_FETCH_DIM_FUNC_ARG:
170 case ZEND_FETCH_DIM_UNSET:
171 case ZEND_FETCH_LIST_W:
172 if (opline->op1_type == IS_CV) {
173 goto add_op1_def;
174 }
175 break;
176 case ZEND_SEND_VAR:
177 case ZEND_CAST:
178 case ZEND_QM_ASSIGN:
179 case ZEND_JMP_SET:
180 case ZEND_COALESCE:
181 case ZEND_FE_RESET_R:
182 if ((build_flags & ZEND_SSA_RC_INFERENCE) && opline->op1_type == IS_CV) {
183 goto add_op1_def;
184 }
185 break;
186 case ZEND_ADD_ARRAY_UNPACK:
187 var_num = EX_VAR_TO_NUM(opline->result.var);
188 if (!zend_bitset_in(def, var_num)) {
189 zend_bitset_incl(use, var_num);
190 }
191 break;
192 case ZEND_ADD_ARRAY_ELEMENT:
193 var_num = EX_VAR_TO_NUM(opline->result.var);
194 if (!zend_bitset_in(def, var_num)) {
195 zend_bitset_incl(use, var_num);
196 }
197 ZEND_FALLTHROUGH;
198 case ZEND_INIT_ARRAY:
199 if (((build_flags & ZEND_SSA_RC_INFERENCE)
200 || (opline->extended_value & ZEND_ARRAY_ELEMENT_REF))
201 && opline->op1_type == IS_CV) {
202 goto add_op1_def;
203 }
204 break;
205 case ZEND_YIELD:
206 if (opline->op1_type == IS_CV
207 && ((op_array->fn_flags & ZEND_ACC_RETURN_REFERENCE)
208 || (build_flags & ZEND_SSA_RC_INFERENCE))) {
209 goto add_op1_def;
210 }
211 break;
212 case ZEND_UNSET_CV:
213 goto add_op1_def;
214 case ZEND_VERIFY_RETURN_TYPE:
215 if (opline->op1_type & (IS_TMP_VAR|IS_VAR|IS_CV)) {
216 goto add_op1_def;
217 }
218 break;
219 case ZEND_FE_FETCH_R:
220 case ZEND_FE_FETCH_RW:
221 #if 0
222 /* This special case was handled above the switch */
223 if (opline->op2_type != IS_CV) {
224 op2_use = -1; /* not used */
225 }
226 #endif
227 zend_bitset_incl(def, EX_VAR_TO_NUM(opline->op2.var));
228 break;
229 case ZEND_BIND_LEXICAL:
230 if ((opline->extended_value & ZEND_BIND_REF) || (build_flags & ZEND_SSA_RC_INFERENCE)) {
231 zend_bitset_incl(def, EX_VAR_TO_NUM(opline->op2.var));
232 }
233 break;
234 default:
235 break;
236 }
237
238 if (opline->result_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
239 zend_bitset_incl(def, EX_VAR_TO_NUM(opline->result.var));
240 }
241 }
242 /* }}} */
243
zend_dfg_add_use_def_op(const zend_op_array * op_array,const zend_op * opline,uint32_t build_flags,zend_bitset use,zend_bitset def)244 ZEND_API void zend_dfg_add_use_def_op(const zend_op_array *op_array, const zend_op *opline, uint32_t build_flags, zend_bitset use, zend_bitset def) /* {{{ */
245 {
246 _zend_dfg_add_use_def_op(op_array, opline, build_flags, use, def);
247 }
248 /* }}} */
249
zend_build_dfg(const zend_op_array * op_array,const zend_cfg * cfg,zend_dfg * dfg,uint32_t build_flags)250 int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg *dfg, uint32_t build_flags) /* {{{ */
251 {
252 int set_size;
253 zend_basic_block *blocks = cfg->blocks;
254 int blocks_count = cfg->blocks_count;
255 zend_bitset tmp, def, use, in, out;
256 int k;
257 int j;
258
259 set_size = dfg->size;
260 tmp = dfg->tmp;
261 def = dfg->def;
262 use = dfg->use;
263 in = dfg->in;
264 out = dfg->out;
265
266 /* Collect "def" and "use" sets */
267 for (j = 0; j < blocks_count; j++) {
268 zend_op *opline, *end;
269 zend_bitset b_use, b_def;
270
271 if ((blocks[j].flags & ZEND_BB_REACHABLE) == 0) {
272 continue;
273 }
274
275 opline = op_array->opcodes + blocks[j].start;
276 end = opline + blocks[j].len;
277 b_use = DFG_BITSET(use, set_size, j);
278 b_def = DFG_BITSET(def, set_size, j);
279 for (; opline < end; opline++) {
280 if (opline->opcode != ZEND_OP_DATA) {
281 _zend_dfg_add_use_def_op(op_array, opline, build_flags, b_use, b_def);
282 }
283 }
284 }
285
286 /* Calculate "in" and "out" sets */
287 {
288 uint32_t worklist_len = zend_bitset_len(blocks_count);
289 zend_bitset worklist;
290 ALLOCA_FLAG(use_heap);
291 worklist = ZEND_BITSET_ALLOCA(worklist_len, use_heap);
292 memset(worklist, 0, worklist_len * ZEND_BITSET_ELM_SIZE);
293 for (j = 0; j < blocks_count; j++) {
294 zend_bitset_incl(worklist, j);
295 }
296 while (!zend_bitset_empty(worklist, worklist_len)) {
297 /* We use the last block on the worklist, because predecessors tend to be located
298 * before the succeeding block, so this converges faster. */
299 j = zend_bitset_last(worklist, worklist_len);
300 zend_bitset_excl(worklist, j);
301
302 if ((blocks[j].flags & ZEND_BB_REACHABLE) == 0) {
303 continue;
304 }
305 if (blocks[j].successors_count != 0) {
306 zend_bitset_copy(DFG_BITSET(out, set_size, j), DFG_BITSET(in, set_size, blocks[j].successors[0]), set_size);
307 for (k = 1; k < blocks[j].successors_count; k++) {
308 zend_bitset_union(DFG_BITSET(out, set_size, j), DFG_BITSET(in, set_size, blocks[j].successors[k]), set_size);
309 }
310 } else {
311 zend_bitset_clear(DFG_BITSET(out, set_size, j), set_size);
312 }
313 zend_bitset_union_with_difference(tmp, DFG_BITSET(use, set_size, j), DFG_BITSET(out, set_size, j), DFG_BITSET(def, set_size, j), set_size);
314 if (!zend_bitset_equal(DFG_BITSET(in, set_size, j), tmp, set_size)) {
315 zend_bitset_copy(DFG_BITSET(in, set_size, j), tmp, set_size);
316
317 /* Add predecessors of changed block to worklist */
318 {
319 int *predecessors = &cfg->predecessors[blocks[j].predecessor_offset];
320 for (k = 0; k < blocks[j].predecessors_count; k++) {
321 zend_bitset_incl(worklist, predecessors[k]);
322 }
323 }
324 }
325 }
326
327 free_alloca(worklist, use_heap);
328 }
329
330 return SUCCESS;
331 }
332 /* }}} */
333
