1 /*
2 +----------------------------------------------------------------------+
3 | Zend Engine, DFG - Data Flow Graph |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 1998-2018 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@zend.com> |
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 (!DFG_ISSET(def, set_size, j, var_num)) {
56 DFG_SET(use, set_size, j, var_num);
57 }
58 }
59 if (next->op2_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
60 var_num = EX_VAR_TO_NUM(next->op2.var);
61 if (!DFG_ISSET(def, set_size, j, var_num)) {
62 DFG_SET(use, set_size, j, var_num);
63 }
64 }
65 }
66 if (opline->op1_type == IS_CV) {
67 var_num = EX_VAR_TO_NUM(opline->op1.var);
68 switch (opline->opcode) {
69 case ZEND_ADD_ARRAY_ELEMENT:
70 case ZEND_INIT_ARRAY:
71 if ((build_flags & ZEND_SSA_RC_INFERENCE)
72 || (opline->extended_value & ZEND_ARRAY_ELEMENT_REF)) {
73 goto op1_def;
74 }
75 goto op1_use;
76 case ZEND_FE_RESET_R:
77 case ZEND_SEND_VAR:
78 case ZEND_CAST:
79 case ZEND_QM_ASSIGN:
80 case ZEND_JMP_SET:
81 case ZEND_COALESCE:
82 if (build_flags & ZEND_SSA_RC_INFERENCE) {
83 goto op1_def;
84 }
85 goto op1_use;
86 case ZEND_YIELD:
87 if ((build_flags & ZEND_SSA_RC_INFERENCE)
88 || (op_array->fn_flags & ZEND_ACC_RETURN_REFERENCE)) {
89 goto op1_def;
90 }
91 goto op1_use;
92 case ZEND_UNSET_CV:
93 case ZEND_ASSIGN:
94 case ZEND_ASSIGN_REF:
95 case ZEND_BIND_GLOBAL:
96 case ZEND_BIND_STATIC:
97 case ZEND_SEND_VAR_EX:
98 case ZEND_SEND_REF:
99 case ZEND_SEND_VAR_NO_REF:
100 case ZEND_SEND_VAR_NO_REF_EX:
101 case ZEND_FE_RESET_RW:
102 case ZEND_ASSIGN_ADD:
103 case ZEND_ASSIGN_SUB:
104 case ZEND_ASSIGN_MUL:
105 case ZEND_ASSIGN_DIV:
106 case ZEND_ASSIGN_MOD:
107 case ZEND_ASSIGN_SL:
108 case ZEND_ASSIGN_SR:
109 case ZEND_ASSIGN_CONCAT:
110 case ZEND_ASSIGN_BW_OR:
111 case ZEND_ASSIGN_BW_AND:
112 case ZEND_ASSIGN_BW_XOR:
113 case ZEND_ASSIGN_POW:
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_VERIFY_RETURN_TYPE:
131 op1_def:
132 /* `def` always come along with dtor or separation,
133 * thus the origin var info might be also `use`d in the feature(CG) */
134 DFG_SET(use, set_size, j, var_num);
135 DFG_SET(def, set_size, j, var_num);
136 break;
137 default:
138 op1_use:
139 if (!DFG_ISSET(def, set_size, j, var_num)) {
140 DFG_SET(use, set_size, j, var_num);
141 }
142 }
143 } else if (opline->op1_type & (IS_VAR|IS_TMP_VAR)) {
144 var_num = EX_VAR_TO_NUM(opline->op1.var);
145 if (!DFG_ISSET(def, set_size, j, var_num)) {
146 DFG_SET(use, set_size, j, var_num);
147 }
148 if (opline->opcode == ZEND_VERIFY_RETURN_TYPE) {
149 DFG_SET(def, set_size, j, var_num);
150 }
151 }
152 if (opline->op2_type == IS_CV) {
153 var_num = EX_VAR_TO_NUM(opline->op2.var);
154 switch (opline->opcode) {
155 case ZEND_ASSIGN:
156 if (build_flags & ZEND_SSA_RC_INFERENCE) {
157 goto op2_def;
158 }
159 goto op2_use;
160 case ZEND_BIND_LEXICAL:
161 if ((build_flags & ZEND_SSA_RC_INFERENCE) || opline->extended_value) {
162 goto op2_def;
163 }
164 goto op2_use;
165 case ZEND_ASSIGN_REF:
166 case ZEND_FE_FETCH_R:
167 case ZEND_FE_FETCH_RW:
168 op2_def:
169 // FIXME: include into "use" too ...?
170 DFG_SET(use, set_size, j, var_num);
171 DFG_SET(def, set_size, j, var_num);
172 break;
173 default:
174 op2_use:
175 if (!DFG_ISSET(def, set_size, j, var_num)) {
176 DFG_SET(use, set_size, j, var_num);
177 }
178 break;
179 }
180 } else if (opline->op2_type & (IS_VAR|IS_TMP_VAR)) {
181 var_num = EX_VAR_TO_NUM(opline->op2.var);
182 if (opline->opcode == ZEND_FE_FETCH_R || opline->opcode == ZEND_FE_FETCH_RW) {
183 DFG_SET(def, set_size, j, var_num);
184 } else {
185 if (!DFG_ISSET(def, set_size, j, var_num)) {
186 DFG_SET(use, set_size, j, var_num);
187 }
188 }
189 }
190 if (opline->result_type & (IS_CV|IS_VAR|IS_TMP_VAR)) {
191 var_num = EX_VAR_TO_NUM(opline->result.var);
192 if ((build_flags & ZEND_SSA_USE_CV_RESULTS)
193 && opline->result_type == IS_CV) {
194 DFG_SET(use, set_size, j, var_num);
195 }
196 DFG_SET(def, set_size, j, var_num);
197 }
198 }
199 }
200 }
201
202 /* Calculate "in" and "out" sets */
203 {
204 uint32_t worklist_len = zend_bitset_len(blocks_count);
205 zend_bitset worklist;
206 ALLOCA_FLAG(use_heap);
207 worklist = ZEND_BITSET_ALLOCA(worklist_len, use_heap);
208 memset(worklist, 0, worklist_len * ZEND_BITSET_ELM_SIZE);
209 for (j = 0; j < blocks_count; j++) {
210 zend_bitset_incl(worklist, j);
211 }
212 while (!zend_bitset_empty(worklist, worklist_len)) {
213 /* We use the last block on the worklist, because predecessors tend to be located
214 * before the succeeding block, so this converges faster. */
215 j = zend_bitset_last(worklist, worklist_len);
216 zend_bitset_excl(worklist, j);
217
218 if ((blocks[j].flags & ZEND_BB_REACHABLE) == 0) {
219 continue;
220 }
221 if (blocks[j].successors_count != 0) {
222 zend_bitset_copy(DFG_BITSET(out, set_size, j), DFG_BITSET(in, set_size, blocks[j].successors[0]), set_size);
223 for (k = 1; k < blocks[j].successors_count; k++) {
224 zend_bitset_union(DFG_BITSET(out, set_size, j), DFG_BITSET(in, set_size, blocks[j].successors[k]), set_size);
225 }
226 } else {
227 zend_bitset_clear(DFG_BITSET(out, set_size, j), set_size);
228 }
229 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);
230 if (!zend_bitset_equal(DFG_BITSET(in, set_size, j), tmp, set_size)) {
231 zend_bitset_copy(DFG_BITSET(in, set_size, j), tmp, set_size);
232
233 /* Add predecessors of changed block to worklist */
234 {
235 int *predecessors = &cfg->predecessors[blocks[j].predecessor_offset];
236 for (k = 0; k < blocks[j].predecessors_count; k++) {
237 zend_bitset_incl(worklist, predecessors[k]);
238 }
239 }
240 }
241 }
242
243 free_alloca(worklist, use_heap);
244 }
245
246 return SUCCESS;
247 }
248 /* }}} */
249
250 /*
251 * Local variables:
252 * tab-width: 4
253 * c-basic-offset: 4
254 * indent-tabs-mode: t
255 * End:
256 */
257
