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 | http://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 "php.h"
20 #include "zend_compile.h"
21 #include "zend_dfg.h"
22
zend_build_dfg(const zend_op_array * op_array,const zend_cfg * cfg,zend_dfg * dfg,uint32_t build_flags)23 int zend_build_dfg(const zend_op_array *op_array, const zend_cfg *cfg, zend_dfg *dfg, uint32_t build_flags) /* {{{ */
24 {
25 int set_size;
26 zend_basic_block *blocks = cfg->blocks;
27 int blocks_count = cfg->blocks_count;
28 zend_bitset tmp, def, use, in, out;
29 int k;
30 uint32_t var_num;
31 int j;
32
33 set_size = dfg->size;
34 tmp = dfg->tmp;
35 def = dfg->def;
36 use = dfg->use;
37 in = dfg->in;
38 out = dfg->out;
39
40 /* Collect "def" and "use" sets */
41 for (j = 0; j < blocks_count; j++) {
42 zend_op *opline, *end;
43 if ((blocks[j].flags & ZEND_BB_REACHABLE) == 0) {
44 continue;
45 }
46
47 opline = op_array->opcodes + blocks[j].start;
48 end = opline + blocks[j].len;
49 for (; opline < end; opline++) {
50 if (opline->opcode != ZEND_OP_DATA) {
51 zend_op *next = opline + 1;
52 if (next < end && next->opcode == ZEND_OP_DATA) {
53 if (next->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
54 var_num = EX_VAR_TO_NUM(next->op1.var);
55 if (next->op1_type == IS_CV && (opline->opcode == ZEND_ASSIGN_OBJ_REF
56 || opline->opcode == ZEND_ASSIGN_STATIC_PROP_REF)) {
57 DFG_SET(use, set_size, j, var_num);
58 DFG_SET(def, set_size, j, var_num);
59 } else {
60 if (!DFG_ISSET(def, set_size, j, var_num)) {
61 DFG_SET(use, set_size, j, var_num);
62 }
63 }
64 }
65 if (next->op2_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
66 var_num = EX_VAR_TO_NUM(next->op2.var);
67 if (!DFG_ISSET(def, set_size, j, var_num)) {
68 DFG_SET(use, set_size, j, var_num);
69 }
70 }
71 }
72 if (opline->op1_type == IS_CV) {
73 var_num = EX_VAR_TO_NUM(opline->op1.var);
74 switch (opline->opcode) {
75 case ZEND_ADD_ARRAY_ELEMENT:
76 case ZEND_INIT_ARRAY:
77 if ((build_flags & ZEND_SSA_RC_INFERENCE)
78 || (opline->extended_value & ZEND_ARRAY_ELEMENT_REF)) {
79 goto op1_def;
80 }
81 goto op1_use;
82 case ZEND_FE_RESET_R:
83 case ZEND_SEND_VAR:
84 case ZEND_CAST:
85 case ZEND_QM_ASSIGN:
86 case ZEND_JMP_SET:
87 case ZEND_COALESCE:
88 if (build_flags & ZEND_SSA_RC_INFERENCE) {
89 goto op1_def;
90 }
91 goto op1_use;
92 case ZEND_YIELD:
93 if ((build_flags & ZEND_SSA_RC_INFERENCE)
94 || (op_array->fn_flags & ZEND_ACC_RETURN_REFERENCE)) {
95 goto op1_def;
96 }
97 goto op1_use;
98 case ZEND_UNSET_CV:
99 case ZEND_ASSIGN:
100 case ZEND_ASSIGN_REF:
101 case ZEND_ASSIGN_OBJ_REF:
102 case ZEND_BIND_GLOBAL:
103 case ZEND_BIND_STATIC:
104 case ZEND_SEND_VAR_EX:
105 case ZEND_SEND_FUNC_ARG:
106 case ZEND_SEND_REF:
107 case ZEND_SEND_VAR_NO_REF:
108 case ZEND_SEND_VAR_NO_REF_EX:
109 case ZEND_FE_RESET_RW:
110 case ZEND_ASSIGN_OP:
111 case ZEND_ASSIGN_DIM_OP:
112 case ZEND_ASSIGN_OBJ_OP:
113 case ZEND_ASSIGN_STATIC_PROP_OP:
114 case ZEND_PRE_INC:
115 case ZEND_PRE_DEC:
116 case ZEND_POST_INC:
117 case ZEND_POST_DEC:
118 case ZEND_ASSIGN_DIM:
119 case ZEND_ASSIGN_OBJ:
120 case ZEND_UNSET_DIM:
121 case ZEND_UNSET_OBJ:
122 case ZEND_FETCH_DIM_W:
123 case ZEND_FETCH_DIM_RW:
124 case ZEND_FETCH_DIM_FUNC_ARG:
125 case ZEND_FETCH_DIM_UNSET:
126 case ZEND_FETCH_OBJ_W:
127 case ZEND_FETCH_OBJ_RW:
128 case ZEND_FETCH_OBJ_FUNC_ARG:
129 case ZEND_FETCH_OBJ_UNSET:
130 case ZEND_FETCH_LIST_W:
131 case ZEND_VERIFY_RETURN_TYPE:
132 case ZEND_PRE_INC_OBJ:
133 case ZEND_PRE_DEC_OBJ:
134 case ZEND_POST_INC_OBJ:
135 case ZEND_POST_DEC_OBJ:
136 op1_def:
137 /* `def` always come along with dtor or separation,
138 * thus the origin var info might be also `use`d in the feature(CG) */
139 DFG_SET(use, set_size, j, var_num);
140 DFG_SET(def, set_size, j, var_num);
141 break;
142 default:
143 op1_use:
144 if (!DFG_ISSET(def, set_size, j, var_num)) {
145 DFG_SET(use, set_size, j, var_num);
146 }
147 }
148 } else if (opline->op1_type & (IS_VAR|IS_TMP_VAR)) {
149 var_num = EX_VAR_TO_NUM(opline->op1.var);
150 if (!DFG_ISSET(def, set_size, j, var_num)) {
151 DFG_SET(use, set_size, j, var_num);
152 }
153 if (opline->opcode == ZEND_VERIFY_RETURN_TYPE) {
154 DFG_SET(def, set_size, j, var_num);
155 }
156 }
157 if (opline->op2_type == IS_CV) {
158 var_num = EX_VAR_TO_NUM(opline->op2.var);
159 switch (opline->opcode) {
160 case ZEND_ASSIGN:
161 if (build_flags & ZEND_SSA_RC_INFERENCE) {
162 goto op2_def;
163 }
164 goto op2_use;
165 case ZEND_BIND_LEXICAL:
166 if ((build_flags & ZEND_SSA_RC_INFERENCE) || (opline->extended_value & ZEND_BIND_REF)) {
167 goto op2_def;
168 }
169 goto op2_use;
170 case ZEND_ASSIGN_REF:
171 case ZEND_FE_FETCH_R:
172 case ZEND_FE_FETCH_RW:
173 op2_def:
174 // FIXME: include into "use" too ...?
175 DFG_SET(use, set_size, j, var_num);
176 DFG_SET(def, set_size, j, var_num);
177 break;
178 default:
179 op2_use:
180 if (!DFG_ISSET(def, set_size, j, var_num)) {
181 DFG_SET(use, set_size, j, var_num);
182 }
183 break;
184 }
185 } else if (opline->op2_type & (IS_VAR|IS_TMP_VAR)) {
186 var_num = EX_VAR_TO_NUM(opline->op2.var);
187 if (opline->opcode == ZEND_FE_FETCH_R || opline->opcode == ZEND_FE_FETCH_RW) {
188 DFG_SET(def, set_size, j, var_num);
189 } else {
190 if (!DFG_ISSET(def, set_size, j, var_num)) {
191 DFG_SET(use, set_size, j, var_num);
192 }
193 }
194 }
195 if (opline->result_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
196 var_num = EX_VAR_TO_NUM(opline->result.var);
197 if ((build_flags & ZEND_SSA_USE_CV_RESULTS)
198 && opline->result_type == IS_CV) {
199 DFG_SET(use, set_size, j, var_num);
200 }
201 DFG_SET(def, set_size, j, var_num);
202 }
203 }
204 }
205 }
206
207 /* Calculate "in" and "out" sets */
208 {
209 uint32_t worklist_len = zend_bitset_len(blocks_count);
210 zend_bitset worklist;
211 ALLOCA_FLAG(use_heap);
212 worklist = ZEND_BITSET_ALLOCA(worklist_len, use_heap);
213 memset(worklist, 0, worklist_len * ZEND_BITSET_ELM_SIZE);
214 for (j = 0; j < blocks_count; j++) {
215 zend_bitset_incl(worklist, j);
216 }
217 while (!zend_bitset_empty(worklist, worklist_len)) {
218 /* We use the last block on the worklist, because predecessors tend to be located
219 * before the succeeding block, so this converges faster. */
220 j = zend_bitset_last(worklist, worklist_len);
221 zend_bitset_excl(worklist, j);
222
223 if ((blocks[j].flags & ZEND_BB_REACHABLE) == 0) {
224 continue;
225 }
226 if (blocks[j].successors_count != 0) {
227 zend_bitset_copy(DFG_BITSET(out, set_size, j), DFG_BITSET(in, set_size, blocks[j].successors[0]), set_size);
228 for (k = 1; k < blocks[j].successors_count; k++) {
229 zend_bitset_union(DFG_BITSET(out, set_size, j), DFG_BITSET(in, set_size, blocks[j].successors[k]), set_size);
230 }
231 } else {
232 zend_bitset_clear(DFG_BITSET(out, set_size, j), set_size);
233 }
234 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);
235 if (!zend_bitset_equal(DFG_BITSET(in, set_size, j), tmp, set_size)) {
236 zend_bitset_copy(DFG_BITSET(in, set_size, j), tmp, set_size);
237
238 /* Add predecessors of changed block to worklist */
239 {
240 int *predecessors = &cfg->predecessors[blocks[j].predecessor_offset];
241 for (k = 0; k < blocks[j].predecessors_count; k++) {
242 zend_bitset_incl(worklist, predecessors[k]);
243 }
244 }
245 }
246 }
247
248 free_alloca(worklist, use_heap);
249 }
250
251 return SUCCESS;
252 }
253 /* }}} */
254
