1 /*
2 +----------------------------------------------------------------------+
3 | Zend OPcache |
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: Andi Gutmans <andi@php.net> |
16 | Zeev Suraski <zeev@php.net> |
17 | Stanislav Malyshev <stas@zend.com> |
18 | Dmitry Stogov <dmitry@php.net> |
19 +----------------------------------------------------------------------+
20 */
21
22 #include "Optimizer/zend_optimizer.h"
23 #include "Optimizer/zend_optimizer_internal.h"
24 #include "zend_API.h"
25 #include "zend_constants.h"
26 #include "zend_execute.h"
27 #include "zend_vm.h"
28 #include "zend_bitset.h"
29
30 #define INVALID_VAR ((uint32_t)-1)
31 #define GET_AVAILABLE_T() \
32 for (i = 0; i < T; i++) { \
33 if (!zend_bitset_in(taken_T, i)) { \
34 break; \
35 } \
36 } \
37 zend_bitset_incl(taken_T, i); \
38 if (i > max) { \
39 max = i; \
40 }
41
zend_optimize_temporary_variables(zend_op_array * op_array,zend_optimizer_ctx * ctx)42 void zend_optimize_temporary_variables(zend_op_array *op_array, zend_optimizer_ctx *ctx)
43 {
44 uint32_t T = op_array->T;
45 int offset = op_array->last_var;
46 uint32_t bitset_len;
47 zend_bitset taken_T; /* T index in use */
48 zend_op **start_of_T; /* opline where T is first used */
49 int *map_T; /* Map's the T to its new index */
50 zend_op *opline, *end;
51 int currT;
52 int i;
53 int max = -1;
54 void *checkpoint = zend_arena_checkpoint(ctx->arena);
55
56 bitset_len = zend_bitset_len(T);
57 taken_T = (zend_bitset) zend_arena_alloc(&ctx->arena, bitset_len * ZEND_BITSET_ELM_SIZE);
58 start_of_T = (zend_op **) zend_arena_alloc(&ctx->arena, T * sizeof(zend_op *));
59 map_T = (int *) zend_arena_alloc(&ctx->arena, T * sizeof(int));
60 memset(map_T, 0xff, T * sizeof(int));
61
62 end = op_array->opcodes;
63 opline = &op_array->opcodes[op_array->last - 1];
64
65 /* Find T definition points */
66 while (opline >= end) {
67 if (opline->result_type & (IS_VAR | IS_TMP_VAR)) {
68 start_of_T[VAR_NUM(opline->result.var) - offset] = opline;
69 }
70 opline--;
71 }
72
73 zend_bitset_clear(taken_T, bitset_len);
74
75 end = op_array->opcodes;
76 opline = &op_array->opcodes[op_array->last - 1];
77
78 while (opline >= end) {
79 if ((opline->op1_type & (IS_VAR | IS_TMP_VAR))) {
80 currT = VAR_NUM(opline->op1.var) - offset;
81 if (opline->opcode == ZEND_ROPE_END) {
82 int num = (((opline->extended_value + 1) * sizeof(zend_string*)) + (sizeof(zval) - 1)) / sizeof(zval);
83 int var;
84
85 var = max;
86 while (var >= 0 && !zend_bitset_in(taken_T, var)) {
87 var--;
88 }
89 max = MAX(max, var + num);
90 var = var + 1;
91 map_T[currT] = var;
92 zend_bitset_incl(taken_T, var);
93 opline->op1.var = NUM_VAR(var + offset);
94 while (num > 1) {
95 num--;
96 zend_bitset_incl(taken_T, var + num);
97 }
98 } else {
99 if (map_T[currT] == INVALID_VAR) {
100 int use_new_var = 0;
101
102 /* Code in "finally" blocks may modify temporary variables.
103 * We allocate new temporaries for values that need to
104 * relive FAST_CALLs.
105 */
106 if ((op_array->fn_flags & ZEND_ACC_HAS_FINALLY_BLOCK) &&
107 (opline->opcode == ZEND_RETURN ||
108 opline->opcode == ZEND_GENERATOR_RETURN ||
109 opline->opcode == ZEND_RETURN_BY_REF ||
110 opline->opcode == ZEND_FREE ||
111 opline->opcode == ZEND_FE_FREE)) {
112 zend_op *curr = opline;
113
114 while (--curr >= end) {
115 if (curr->opcode == ZEND_FAST_CALL) {
116 use_new_var = 1;
117 break;
118 } else if (curr->opcode != ZEND_FREE &&
119 curr->opcode != ZEND_FE_FREE &&
120 curr->opcode != ZEND_VERIFY_RETURN_TYPE &&
121 curr->opcode != ZEND_DISCARD_EXCEPTION) {
122 break;
123 }
124 }
125 }
126 if (use_new_var) {
127 i = ++max;
128 zend_bitset_incl(taken_T, i);
129 } else {
130 GET_AVAILABLE_T();
131 }
132 map_T[currT] = i;
133 }
134 opline->op1.var = NUM_VAR(map_T[currT] + offset);
135 }
136 }
137
138 if ((opline->op2_type & (IS_VAR | IS_TMP_VAR))) {
139 currT = VAR_NUM(opline->op2.var) - offset;
140 if (map_T[currT] == INVALID_VAR) {
141 GET_AVAILABLE_T();
142 map_T[currT] = i;
143 }
144 opline->op2.var = NUM_VAR(map_T[currT] + offset);
145 }
146
147 if (opline->result_type & (IS_VAR | IS_TMP_VAR)) {
148 currT = VAR_NUM(opline->result.var) - offset;
149 if (map_T[currT] == INVALID_VAR) {
150 /* As a result of DCE, an opcode may have an unused result. */
151 GET_AVAILABLE_T();
152 map_T[currT] = i;
153 }
154 opline->result.var = NUM_VAR(map_T[currT] + offset);
155 if (start_of_T[currT] == opline) {
156 /* ZEND_FAST_CALL can not share temporary var with others
157 * since the fast_var could also be set by ZEND_HANDLE_EXCEPTION
158 * which could be ahead of it */
159 if (opline->opcode != ZEND_FAST_CALL) {
160 zend_bitset_excl(taken_T, map_T[currT]);
161 }
162 if (opline->opcode == ZEND_ROPE_INIT) {
163 uint32_t num = ((opline->extended_value * sizeof(zend_string*)) + (sizeof(zval) - 1)) / sizeof(zval);
164 while (num > 1) {
165 num--;
166 zend_bitset_excl(taken_T, map_T[currT]+num);
167 }
168 }
169 }
170 }
171
172 opline--;
173 }
174
175 zend_arena_release(&ctx->arena, checkpoint);
176 op_array->T = max + 1;
177 }
178
