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 /* pass 10:
23 * - remove NOPs
24 */
25
26 #include "Optimizer/zend_optimizer.h"
27 #include "Optimizer/zend_optimizer_internal.h"
28 #include "zend_API.h"
29 #include "zend_constants.h"
30 #include "zend_execute.h"
31 #include "zend_vm.h"
32
zend_optimizer_nop_removal(zend_op_array * op_array,zend_optimizer_ctx * ctx)33 void zend_optimizer_nop_removal(zend_op_array *op_array, zend_optimizer_ctx *ctx)
34 {
35 zend_op *end, *opline;
36 uint32_t new_count, i, shift;
37 int j;
38 uint32_t *shiftlist;
39 ALLOCA_FLAG(use_heap);
40
41 shiftlist = (uint32_t *)do_alloca(sizeof(uint32_t) * op_array->last, use_heap);
42 i = new_count = shift = 0;
43 end = op_array->opcodes + op_array->last;
44 for (opline = op_array->opcodes; opline < end; opline++) {
45
46 /* Kill JMP-over-NOP-s */
47 if (opline->opcode == ZEND_JMP && ZEND_OP1_JMP_ADDR(opline) > op_array->opcodes + i) {
48 /* check if there are only NOPs under the branch */
49 zend_op *target = ZEND_OP1_JMP_ADDR(opline) - 1;
50
51 while (target->opcode == ZEND_NOP) {
52 target--;
53 }
54 if (target == opline) {
55 /* only NOPs */
56 opline->opcode = ZEND_NOP;
57 }
58 }
59
60 shiftlist[i++] = shift;
61 if (opline->opcode == ZEND_NOP) {
62 shift++;
63 } else {
64 if (shift) {
65 zend_op *new_opline = op_array->opcodes + new_count;
66
67 *new_opline = *opline;
68 zend_optimizer_migrate_jump(op_array, new_opline, opline);
69 }
70 new_count++;
71 }
72 }
73
74 if (shift) {
75 op_array->last = new_count;
76 end = op_array->opcodes + op_array->last;
77
78 /* update JMPs */
79 for (opline = op_array->opcodes; opline<end; opline++) {
80 zend_optimizer_shift_jump(op_array, opline, shiftlist);
81 }
82
83 /* update try/catch array */
84 for (j = 0; j < op_array->last_try_catch; j++) {
85 op_array->try_catch_array[j].try_op -= shiftlist[op_array->try_catch_array[j].try_op];
86 op_array->try_catch_array[j].catch_op -= shiftlist[op_array->try_catch_array[j].catch_op];
87 if (op_array->try_catch_array[j].finally_op) {
88 op_array->try_catch_array[j].finally_op -= shiftlist[op_array->try_catch_array[j].finally_op];
89 op_array->try_catch_array[j].finally_end -= shiftlist[op_array->try_catch_array[j].finally_end];
90 }
91 }
92 }
93 free_alloca(shiftlist, use_heap);
94 }
95
