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 #include "zend_observer.h"
30
31 #define INVALID_VAR ((uint32_t)-1)
32 #define GET_AVAILABLE_T() \
33 for (i = 0; i < T; i++) { \
34 if (!zend_bitset_in(taken_T, i)) { \
35 break; \
36 } \
37 } \
38 zend_bitset_incl(taken_T, i); \
39 if (i > max) { \
40 max = i; \
41 }
42
zend_optimize_temporary_variables(zend_op_array * op_array,zend_optimizer_ctx * ctx)43 void zend_optimize_temporary_variables(zend_op_array *op_array, zend_optimizer_ctx *ctx)
44 {
45 uint32_t T = op_array->T;
46 int offset = op_array->last_var;
47 uint32_t bitset_len;
48 zend_bitset taken_T; /* T index in use */
49 zend_op **start_of_T; /* opline where T is first used */
50 int *map_T; /* Map's the T to its new index */
51 zend_op *opline, *end;
52 int currT;
53 int i;
54 int max = -1;
55 void *checkpoint = zend_arena_checkpoint(ctx->arena);
56
57 bitset_len = zend_bitset_len(T);
58 taken_T = (zend_bitset) zend_arena_alloc(&ctx->arena, bitset_len * ZEND_BITSET_ELM_SIZE);
59 start_of_T = (zend_op **) zend_arena_alloc(&ctx->arena, T * sizeof(zend_op *));
60 map_T = (int *) zend_arena_alloc(&ctx->arena, T * sizeof(int));
61 memset(map_T, 0xff, T * sizeof(int));
62
63 end = op_array->opcodes;
64 opline = &op_array->opcodes[op_array->last - 1];
65
66 /* Find T definition points */
67 while (opline >= end) {
68 if (opline->result_type & (IS_VAR | IS_TMP_VAR)) {
69 start_of_T[VAR_NUM(opline->result.var) - offset] = opline;
70 }
71 opline--;
72 }
73
74 zend_bitset_clear(taken_T, bitset_len);
75
76 end = op_array->opcodes;
77 opline = &op_array->opcodes[op_array->last - 1];
78
79 while (opline >= end) {
80 if ((opline->op1_type & (IS_VAR | IS_TMP_VAR))) {
81 currT = VAR_NUM(opline->op1.var) - offset;
82 if (opline->opcode == ZEND_ROPE_END) {
83 int num = (((opline->extended_value + 1) * sizeof(zend_string*)) + (sizeof(zval) - 1)) / sizeof(zval);
84 int var;
85
86 var = max;
87 while (var >= 0 && !zend_bitset_in(taken_T, var)) {
88 var--;
89 }
90 max = MAX(max, var + num);
91 var = var + 1;
92 map_T[currT] = var;
93 zend_bitset_incl(taken_T, var);
94 opline->op1.var = NUM_VAR(var + offset);
95 while (num > 1) {
96 num--;
97 zend_bitset_incl(taken_T, var + num);
98 }
99 } else {
100 if (map_T[currT] == INVALID_VAR) {
101 int use_new_var = 0;
102
103 /* Code in "finally" blocks may modify temporary variables.
104 * We allocate new temporaries for values that need to
105 * relive FAST_CALLs.
106 */
107 if ((op_array->fn_flags & ZEND_ACC_HAS_FINALLY_BLOCK) &&
108 (opline->opcode == ZEND_RETURN ||
109 opline->opcode == ZEND_GENERATOR_RETURN ||
110 opline->opcode == ZEND_RETURN_BY_REF ||
111 opline->opcode == ZEND_FREE ||
112 opline->opcode == ZEND_FE_FREE)) {
113 zend_op *curr = opline;
114
115 while (--curr >= end) {
116 if (curr->opcode == ZEND_FAST_CALL) {
117 use_new_var = 1;
118 break;
119 } else if (curr->opcode != ZEND_FREE &&
120 curr->opcode != ZEND_FE_FREE &&
121 curr->opcode != ZEND_VERIFY_RETURN_TYPE &&
122 curr->opcode != ZEND_DISCARD_EXCEPTION) {
123 break;
124 }
125 }
126 }
127 if (use_new_var) {
128 i = ++max;
129 zend_bitset_incl(taken_T, i);
130 } else {
131 GET_AVAILABLE_T();
132 }
133 map_T[currT] = i;
134 }
135 opline->op1.var = NUM_VAR(map_T[currT] + offset);
136 }
137 }
138
139 if ((opline->op2_type & (IS_VAR | IS_TMP_VAR))) {
140 currT = VAR_NUM(opline->op2.var) - offset;
141 if (map_T[currT] == INVALID_VAR) {
142 GET_AVAILABLE_T();
143 map_T[currT] = i;
144 }
145 opline->op2.var = NUM_VAR(map_T[currT] + offset);
146 }
147
148 if (opline->result_type & (IS_VAR | IS_TMP_VAR)) {
149 currT = VAR_NUM(opline->result.var) - offset;
150 if (map_T[currT] == INVALID_VAR) {
151 /* As a result of DCE, an opcode may have an unused result. */
152 GET_AVAILABLE_T();
153 map_T[currT] = i;
154 }
155 opline->result.var = NUM_VAR(map_T[currT] + offset);
156 if (start_of_T[currT] == opline) {
157 /* ZEND_FAST_CALL can not share temporary var with others
158 * since the fast_var could also be set by ZEND_HANDLE_EXCEPTION
159 * which could be ahead of it */
160 if (opline->opcode != ZEND_FAST_CALL) {
161 zend_bitset_excl(taken_T, map_T[currT]);
162 }
163 if (opline->opcode == ZEND_ROPE_INIT) {
164 uint32_t num = ((opline->extended_value * sizeof(zend_string*)) + (sizeof(zval) - 1)) / sizeof(zval);
165 while (num > 1) {
166 num--;
167 zend_bitset_excl(taken_T, map_T[currT]+num);
168 }
169 }
170 }
171 }
172
173 opline--;
174 }
175
176 zend_arena_release(&ctx->arena, checkpoint);
177 op_array->T = max + 1 + ZEND_OBSERVER_ENABLED; // reserve last temporary for observers if enabled
178 }
179
