/src/php-src/Zend/Optimizer/pass3.c

Source
/*
   +----------------------------------------------------------------------+
   | Zend OPcache                                                         |
   +----------------------------------------------------------------------+
   | Copyright © The PHP Group and Contributors.                          |
   +----------------------------------------------------------------------+
   | This source file is subject to the Modified BSD License that is      |
   | bundled with this package in the file LICENSE, and is available      |
   | through the World Wide Web at <https://www.php.net/license/>.        |
   |                                                                      |
   | SPDX-License-Identifier: BSD-3-Clause                                |
   +----------------------------------------------------------------------+
   | Authors: Andi Gutmans <andi@php.net>                                 |
   |          Zeev Suraski <zeev@php.net>                                 |
   |          Stanislav Malyshev <stas@zend.com>                          |
   |          Dmitry Stogov <dmitry@php.net>                              |
   +----------------------------------------------------------------------+
*/

/* pass 3: (Jump optimization)
 * - optimize series of JMPs
 */

#include "Optimizer/zend_optimizer.h"
#include "Optimizer/zend_optimizer_internal.h"
#include "zend_API.h"
#include "zend_constants.h"
#include "zend_execute.h"
#include "zend_vm.h"

/* we use "jmp_hitlist" to avoid infinity loops during jmp optimization */
static zend_always_inline bool in_hitlist(const zend_op *target, zend_op **jmp_hitlist, int jmp_hitlist_count)
{
  int i;

  for (i = 0; i < jmp_hitlist_count; i++) {
    if (jmp_hitlist[i] == target) {
      return true;
    }
  }
  return false;
}

#define CHECK_LOOP(target) \
  if (EXPECTED(!in_hitlist(target, jmp_hitlist, jmp_hitlist_count))) { \
    jmp_hitlist[jmp_hitlist_count++] = target;  \
  } else { \
    break; \
  }

void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
{
  zend_op *opline;
  zend_op *target;
  zend_op **jmp_hitlist;
  int jmp_hitlist_count;
  ALLOCA_FLAG(use_heap);

  jmp_hitlist = (zend_op**)do_alloca(sizeof(zend_op*)*op_array->last, use_heap);
  opline = op_array->opcodes;
  const zend_op *end =  opline + op_array->last;

  while (opline < end) {

    switch (opline->opcode) {
      case ZEND_JMP:
        jmp_hitlist_count = 0;

        target = ZEND_OP1_JMP_ADDR(opline);
        while (1) {
          if (target->opcode == ZEND_JMP) {
            /* convert JMP L1 ... L1: JMP L2 to JMP L2 .. L1: JMP L2 */
            target = ZEND_OP1_JMP_ADDR(target);
            CHECK_LOOP(target);
          } else if (target->opcode == ZEND_NOP) {
            target = target + 1;
          } else {
            break;
          }
          ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target);
        }

        if (target == opline + 1) {
          /* convert L: JMP L+1 to NOP */
          MAKE_NOP(opline);
        } else if ((target->opcode == ZEND_RETURN ||
                    target->opcode == ZEND_RETURN_BY_REF ||
                    target->opcode == ZEND_GENERATOR_RETURN) &&
                   !(op_array->fn_flags & ZEND_ACC_HAS_FINALLY_BLOCK)) {
          /* JMP L, L: RETURN to immediate RETURN */
          *opline = *target;
          if (opline->op1_type == IS_CONST) {
            zval zv;
            ZVAL_COPY(&zv, &ZEND_OP1_LITERAL(opline));
            opline->op1.constant = zend_optimizer_add_literal(op_array, &zv);
          }
        } else if (opline > op_array->opcodes &&
                   ((opline-1)->opcode == ZEND_JMPZ ||
                    (opline-1)->opcode == ZEND_JMPNZ)) {
            if (ZEND_OP2_JMP_ADDR(opline-1) == target) {
            /* JMPZ(X,L1), JMP(L1) -> NOP, JMP(L1) */
            zend_optimizer_convert_to_free_op1(op_array, opline - 1);
            }
        }
        break;

      case ZEND_JMP_SET:
      case ZEND_COALESCE:
        jmp_hitlist_count = 0;

        target = ZEND_OP2_JMP_ADDR(opline);
        while (1) {
          if (target->opcode == ZEND_JMP) {
            target = ZEND_OP1_JMP_ADDR(target);
            CHECK_LOOP(target);
          } else if (target->opcode == ZEND_NOP) {
            target = target + 1;
          } else {
            break;
          }
          ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
        }
        break;

      case ZEND_JMPZ:
      case ZEND_JMPNZ:
        jmp_hitlist_count = 0;

        target = ZEND_OP2_JMP_ADDR(opline);
        while (1) {
          if (target->opcode == ZEND_JMP) {
            /* plain JMP */
            /* JMPZ(X,L1), L1: JMP(L2) => JMPZ(X,L2), L1: JMP(L2) */
            target = ZEND_OP1_JMP_ADDR(target);
            CHECK_LOOP(target);
          } else if (target->opcode == opline->opcode &&
                     SAME_VAR(opline->op1, target->op1)) {
            /* same opcode and same var as this opcode */
            /* JMPZ(X,L1), L1: JMPZ(X,L2) => JMPZ(X,L2), L1: JMPZ(X,L2) */
            target = ZEND_OP2_JMP_ADDR(target);
            CHECK_LOOP(target);
          } else if (target->opcode == INV_COND(opline->opcode) &&
                     SAME_VAR(opline->op1, target->op1)) {
            /* convert JMPZ(X,L1), L1: JMPNZ(X,L2) to
               JMPZ(X,L1+1) */
            target = target + 1;
          } else if (target->opcode == ZEND_NOP) {
            target = target + 1;
          } else {
            break;
          }
          ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
        }

        /* convert L: JMPZ L+1 to NOP */
        if (target == opline + 1) {
          zend_optimizer_convert_to_free_op1(op_array, opline);
        }
        break;

      case ZEND_JMPZ_EX:
      case ZEND_JMPNZ_EX:
        jmp_hitlist_count = 0;

        target = ZEND_OP2_JMP_ADDR(opline);
        while (1) {
          if (target->opcode == ZEND_JMP) {
            /* plain JMP */
            /* JMPZ_EX(X,L1), L1: JMP(L2) => JMPZ_EX(X,L2), L1: JMP(L2) */
            target = ZEND_OP1_JMP_ADDR(target);
            CHECK_LOOP(target);
          } else if (target->opcode == opline->opcode-3 &&
                     (SAME_VAR(target->op1, opline->result) ||
                      SAME_VAR(target->op1, opline->op1))) {
            /* convert T=JMPZ_EX(X,L1), L1: JMPZ(T,L2) to
               JMPZ_EX(X,L2) */
            target = ZEND_OP2_JMP_ADDR(target);
            CHECK_LOOP(target);
          } else if (target->opcode == opline->opcode &&
                     target->result.var == opline->result.var &&
                     (SAME_VAR(target->op1, opline->result) ||
                      SAME_VAR(target->op1, opline->op1))) {
            /* convert T=JMPZ_EX(X,L1), L1: T=JMPZ_EX(T,L2) to
               JMPZ_EX(X,L2) */
            target = ZEND_OP2_JMP_ADDR(target);
            CHECK_LOOP(target);
          } else if (target->opcode == INV_EX_COND(opline->opcode) &&
                     (SAME_VAR(target->op1, opline->result) ||
                      SAME_VAR(target->op1, opline->op1))) {
             /* convert T=JMPZ_EX(X,L1), L1: JMPNZ(T,L2) to
              JMPZ_EX(X,L1+1) */
            target = target + 1;
          } else if (target->opcode == INV_EX_COND_EX(opline->opcode) &&
                     target->result.var == opline->result.var &&
                     (SAME_VAR(target->op1, opline->result) ||
                      SAME_VAR(target->op1, opline->op1))) {
             /* convert T=JMPZ_EX(X,L1), L1: T=JMPNZ_EX(T,L2) to
              JMPZ_EX(X,L1+1) */
            target = target + 1;
          } else if (target->opcode == ZEND_BOOL &&
                     (SAME_VAR(target->op1, opline->result) ||
                      SAME_VAR(target->op1, opline->op1))) {
            /* convert Y = JMPZ_EX(X,L1), L1: Z = BOOL(Y) to
               Z = JMPZ_EX(X,L1+1) */

            /* NOTE: This optimization pattern is not safe, but works, */
            /*       because result of JMPZ_EX instruction             */
            /*       is not used on the following path and             */
            /*       should be used once on the branch path.           */
            /*                                                         */
            /*       The pattern works well only if jumps processed in */
            /*       direct order, otherwise it breaks JMPZ_EX         */
            /*       sequences too early.                              */
            opline->result.var = target->result.var;
            target = target + 1;
            CHECK_LOOP(target);
          } else if (target->opcode == ZEND_NOP) {
            target = target + 1;
          } else {
            break;
          }
          ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
        }

        /* convert L: T = JMPZ_EX X,L+1 to T = BOOL(X) */
        if (target == opline + 1) {
          opline->opcode = ZEND_BOOL;
          opline->op2.num = 0;
        }
        break;
    }
    opline++;
  }
  free_alloca(jmp_hitlist, use_heap);
}

Coverage Report

Created: 2026-09-14 06:25

Line	Count	Source
1		/*
2		+----------------------------------------------------------------------+
3		\| Zend OPcache \|
4		+----------------------------------------------------------------------+
5		\| Copyright © The PHP Group and Contributors. \|
6		+----------------------------------------------------------------------+
7		\| This source file is subject to the Modified BSD License that is \|
8		\| bundled with this package in the file LICENSE, and is available \|
9		\| through the World Wide Web at <https://www.php.net/license/>. \|
10		\| \|
11		\| SPDX-License-Identifier: BSD-3-Clause \|
12		+----------------------------------------------------------------------+
13		\| Authors: Andi Gutmans <andi@php.net> \|
14		\| Zeev Suraski <zeev@php.net> \|
15		\| Stanislav Malyshev <stas@zend.com> \|
16		\| Dmitry Stogov <dmitry@php.net> \|
17		+----------------------------------------------------------------------+
18		*/
19
20		/* pass 3: (Jump optimization)
21		* - optimize series of JMPs
22		*/
23
24		#include "Optimizer/zend_optimizer.h"
25		#include "Optimizer/zend_optimizer_internal.h"
26		#include "zend_API.h"
27		#include "zend_constants.h"
28		#include "zend_execute.h"
29		#include "zend_vm.h"
30
31		/* we use "jmp_hitlist" to avoid infinity loops during jmp optimization */
32		static zend_always_inline bool in_hitlist(const zend_op target, zend_op *jmp_hitlist, int jmp_hitlist_count)
33	40.0k	{
34	40.0k	int i;
35
36	141k	for (i = 0; i < jmp_hitlist_count; i++) {
37	101k	if (jmp_hitlist[i] == target) {
38	116	return true;
39	116	}
40	101k	}
41	39.9k	return false;
42	40.0k	}
43
44		#define CHECK_LOOP(target) \
45	40.0k	if (EXPECTED(!in_hitlist(target, jmp_hitlist, jmp_hitlist_count))) { \
46	39.9k	jmp_hitlist[jmp_hitlist_count++] = target; \
47	39.9k	} else { \
48	116	break; \
49	116	}
50
51		void zend_optimizer_pass3(zend_op_array op_array, zend_optimizer_ctx ctx)
52	115k	{
53	115k	zend_op *opline;
54	115k	zend_op *target;
55	115k	zend_op **jmp_hitlist;
56	115k	int jmp_hitlist_count;
57	115k	ALLOCA_FLAG(use_heap);
58
59	115k	jmp_hitlist = (zend_op*)do_alloca(sizeof(zend_op)*op_array->last, use_heap);
60	115k	opline = op_array->opcodes;
61	115k	const zend_op *end = opline + op_array->last;
62
63	2.94M	while (opline < end) {
64
65	2.82M	switch (opline->opcode) {
66	75.1k	case ZEND_JMP:
67	75.1k	jmp_hitlist_count = 0;
68
69	75.1k	target = ZEND_OP1_JMP_ADDR(opline);
70	86.5k	while (1) {
71	86.5k	if (target->opcode == ZEND_JMP) {
72		/* convert JMP L1 ... L1: JMP L2 to JMP L2 .. L1: JMP L2 */
73	11.1k	target = ZEND_OP1_JMP_ADDR(target);
74	11.1k	CHECK_LOOP(target);
75	75.3k	} else if (target->opcode == ZEND_NOP) {
76	315	target = target + 1;
77	75.0k	} else {
78	75.0k	break;
79	75.0k	}
80	11.3k	ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target);
81	11.3k	}
82
83	75.1k	if (target == opline + 1) {
84		/* convert L: JMP L+1 to NOP */
85	3.00k	MAKE_NOP(opline);
86	72.1k	} else if ((target->opcode == ZEND_RETURN \|\|
87	64.8k	target->opcode == ZEND_RETURN_BY_REF \|\|
88	64.6k	target->opcode == ZEND_GENERATOR_RETURN) &&
89	7.60k	!(op_array->fn_flags & ZEND_ACC_HAS_FINALLY_BLOCK)) {
90		/* JMP L, L: RETURN to immediate RETURN */
91	7.13k	opline = target;
92	7.13k	if (opline->op1_type == IS_CONST) {
93	6.78k	zval zv;
94	6.78k	ZVAL_COPY(&zv, &ZEND_OP1_LITERAL(opline));
95	6.78k	opline->op1.constant = zend_optimizer_add_literal(op_array, &zv);
96	6.78k	}
97	64.9k	} else if (opline > op_array->opcodes &&
98	64.6k	((opline-1)->opcode == ZEND_JMPZ \|\|
99	64.2k	(opline-1)->opcode == ZEND_JMPNZ)) {
100	1.16k	if (ZEND_OP2_JMP_ADDR(opline-1) == target) {
101		/* JMPZ(X,L1), JMP(L1) -> NOP, JMP(L1) */
102	80	zend_optimizer_convert_to_free_op1(op_array, opline - 1);
103	80	}
104	1.16k	}
105	75.1k	break;
106
107	3.60k	case ZEND_JMP_SET:
108	9.22k	case ZEND_COALESCE:
109	9.22k	jmp_hitlist_count = 0;
110
111	9.22k	target = ZEND_OP2_JMP_ADDR(opline);
112	9.22k	while (1) {
113	9.22k	if (target->opcode == ZEND_JMP) {
114	2	target = ZEND_OP1_JMP_ADDR(target);
115	2	CHECK_LOOP(target);
116	9.22k	} else if (target->opcode == ZEND_NOP) {
117	0	target = target + 1;
118	9.22k	} else {
119	9.22k	break;
120	9.22k	}
121	2	ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
122	2	}
123	9.22k	break;
124
125	22.2k	case ZEND_JMPZ:
126	34.8k	case ZEND_JMPNZ:
127	34.8k	jmp_hitlist_count = 0;
128
129	34.8k	target = ZEND_OP2_JMP_ADDR(opline);
130	45.4k	while (1) {
131	45.4k	if (target->opcode == ZEND_JMP) {
132		/* plain JMP */
133		/* JMPZ(X,L1), L1: JMP(L2) => JMPZ(X,L2), L1: JMP(L2) */
134	10.3k	target = ZEND_OP1_JMP_ADDR(target);
135	10.3k	CHECK_LOOP(target);
136	35.0k	} else if (target->opcode == opline->opcode &&
137	438	SAME_VAR(opline->op1, target->op1)) {
138		/* same opcode and same var as this opcode */
139		/* JMPZ(X,L1), L1: JMPZ(X,L2) => JMPZ(X,L2), L1: JMPZ(X,L2) */
140	180	target = ZEND_OP2_JMP_ADDR(target);
141	180	CHECK_LOOP(target);
142	34.9k	} else if (target->opcode == INV_COND(opline->opcode) &&
143	183	SAME_VAR(opline->op1, target->op1)) {
144		/* convert JMPZ(X,L1), L1: JMPNZ(X,L2) to
145		JMPZ(X,L1+1) */
146	0	target = target + 1;
147	34.9k	} else if (target->opcode == ZEND_NOP) {
148	125	target = target + 1;
149	34.7k	} else {
150	34.7k	break;
151	34.7k	}
152	10.6k	ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
153	10.6k	}
154
155		/* convert L: JMPZ L+1 to NOP */
156	34.8k	if (target == opline + 1) {
157	157	zend_optimizer_convert_to_free_op1(op_array, opline);
158	157	}
159	34.8k	break;
160
161	4.15k	case ZEND_JMPZ_EX:
162	8.21k	case ZEND_JMPNZ_EX:
163	8.21k	jmp_hitlist_count = 0;
164
165	8.21k	target = ZEND_OP2_JMP_ADDR(opline);
166	28.2k	while (1) {
167	28.2k	if (target->opcode == ZEND_JMP) {
168		/* plain JMP */
169		/* JMPZ_EX(X,L1), L1: JMP(L2) => JMPZ_EX(X,L2), L1: JMP(L2) */
170	262	target = ZEND_OP1_JMP_ADDR(target);
171	262	CHECK_LOOP(target);
172	27.9k	} else if (target->opcode == opline->opcode-3 &&
173	1.25k	(SAME_VAR(target->op1, opline->result) \|\|
174	1.23k	SAME_VAR(target->op1, opline->op1))) {
175		/* convert T=JMPZ_EX(X,L1), L1: JMPZ(T,L2) to
176		JMPZ_EX(X,L2) */
177	1.23k	target = ZEND_OP2_JMP_ADDR(target);
178	1.23k	CHECK_LOOP(target);
179	26.7k	} else if (target->opcode == opline->opcode &&
180	16.1k	target->result.var == opline->result.var &&
181	16.0k	(SAME_VAR(target->op1, opline->result) \|\|
182	16.0k	SAME_VAR(target->op1, opline->op1))) {
183		/* convert T=JMPZ_EX(X,L1), L1: T=JMPZ_EX(T,L2) to
184		JMPZ_EX(X,L2) */
185	16.0k	target = ZEND_OP2_JMP_ADDR(target);
186	16.0k	CHECK_LOOP(target);
187	16.0k	} else if (target->opcode == INV_EX_COND(opline->opcode) &&
188	654	(SAME_VAR(target->op1, opline->result) \|\|
189	646	SAME_VAR(target->op1, opline->op1))) {
190		/* convert T=JMPZ_EX(X,L1), L1: JMPNZ(T,L2) to
191		JMPZ_EX(X,L1+1) */
192	646	target = target + 1;
193	10.0k	} else if (target->opcode == INV_EX_COND_EX(opline->opcode) &&
194	960	target->result.var == opline->result.var &&
195	960	(SAME_VAR(target->op1, opline->result) \|\|
196	960	SAME_VAR(target->op1, opline->op1))) {
197		/* convert T=JMPZ_EX(X,L1), L1: T=JMPNZ_EX(T,L2) to
198		JMPZ_EX(X,L1+1) */
199	960	target = target + 1;
200	9.05k	} else if (target->opcode == ZEND_BOOL &&
201	1.35k	(SAME_VAR(target->op1, opline->result) \|\|
202	833	SAME_VAR(target->op1, opline->op1))) {
203		/* convert Y = JMPZ_EX(X,L1), L1: Z = BOOL(Y) to
204		Z = JMPZ_EX(X,L1+1) */
205
206		/* NOTE: This optimization pattern is not safe, but works, */
207		/* because result of JMPZ_EX instruction */
208		/* is not used on the following path and */
209		/* should be used once on the branch path. */
210		/* */
211		/* The pattern works well only if jumps processed in */
212		/* direct order, otherwise it breaks JMPZ_EX */
213		/* sequences too early. */
214	833	opline->result.var = target->result.var;
215	833	target = target + 1;
216	833	CHECK_LOOP(target);
217	8.22k	} else if (target->opcode == ZEND_NOP) {
218	4	target = target + 1;
219	8.21k	} else {
220	8.21k	break;
221	8.21k	}
222	19.9k	ZEND_SET_OP_JMP_ADDR(opline, opline->op2, target);
223	19.9k	}
224
225		/* convert L: T = JMPZ_EX X,L+1 to T = BOOL(X) */
226	8.21k	if (target == opline + 1) {
227	0	opline->opcode = ZEND_BOOL;
228	0	opline->op2.num = 0;
229	0	}
230	8.21k	break;
231	2.82M	}
232	2.82M	opline++;
233	2.82M	}
234	115k	free_alloca(jmp_hitlist, use_heap);
235	115k	}