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

Source
/*
   +----------------------------------------------------------------------+
   | Zend OPcache, Escape Analysis                                        |
   +----------------------------------------------------------------------+
   | Copyright (c) The PHP Group                                          |
   +----------------------------------------------------------------------+
   | This source file is subject to version 3.01 of the PHP license,      |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | https://www.php.net/license/3_01.txt                                 |
   | If you did not receive a copy of the PHP license and are unable to   |
   | obtain it through the world-wide-web, please send a note to          |
   | license@php.net so we can mail you a copy immediately.               |
   +----------------------------------------------------------------------+
   | Authors: Dmitry Stogov <dmitry@php.net>                              |
   +----------------------------------------------------------------------+
*/

#include "Optimizer/zend_optimizer.h"
#include "Optimizer/zend_optimizer_internal.h"
#include "zend_bitset.h"
#include "zend_cfg.h"
#include "zend_ssa.h"
#include "zend_inference.h"
#include "zend_dump.h"

/*
 * T. Kotzmann and H. Mossenbock. Escape analysis  in the context of dynamic
 * compilation and deoptimization. In Proceedings of the International
 * Conference on Virtual Execution Environments, pages 111-120, Chicago,
 * June 2005
 */

static zend_always_inline void union_find_init(int *parent, int *size, int count) /* {{{ */
{
  int i;

  for (i = 0; i < count; i++) {
    parent[i] = i;
    size[i] = 1;
  }
}
/* }}} */

static zend_always_inline int union_find_root(int *parent, int i) /* {{{ */
{
  int p = parent[i];

  while (i != p) {
    p = parent[p];
    parent[i] = p;
    i = p;
    p = parent[i];
  }
  return i;
}
/* }}} */

static zend_always_inline void union_find_unite(int *parent, int *size, int i, int j) /* {{{ */
{
  int r1 = union_find_root(parent, i);
  int r2 = union_find_root(parent, j);

  if (r1 != r2) {
    if (size[r1] < size[r2]) {
      parent[r1] = r2;
      size[r2] += size[r1];
    } else {
      parent[r2] = r1;
      size[r1] += size[r2];
    }
  }
}
/* }}} */

static zend_result zend_build_equi_escape_sets(int *parent, zend_op_array *op_array, zend_ssa *ssa) /* {{{ */
{
  zend_ssa_var *ssa_vars = ssa->vars;
  int ssa_vars_count = ssa->vars_count;
  zend_ssa_phi *p;
  int i, j;
  int *size;
  ALLOCA_FLAG(use_heap)

  size = do_alloca(sizeof(int) * ssa_vars_count, use_heap);
  if (!size) {
    return FAILURE;
  }
  union_find_init(parent, size, ssa_vars_count);

  for (i = 0; i < ssa_vars_count; i++) {
    if (ssa_vars[i].definition_phi) {
      p = ssa_vars[i].definition_phi;
      if (p->pi >= 0) {
        union_find_unite(parent, size, i, p->sources[0]);
      } else {
        for (j = 0; j < ssa->cfg.blocks[p->block].predecessors_count; j++) {
          union_find_unite(parent, size, i, p->sources[j]);
        }
      }
    } else if (ssa_vars[i].definition >= 0) {
      int def = ssa_vars[i].definition;
      zend_ssa_op *op = ssa->ops + def;
      zend_op *opline =  op_array->opcodes + def;

      if (op->op1_def >= 0) {
        if (op->op1_use >= 0) {
          if (opline->opcode != ZEND_ASSIGN) {
            union_find_unite(parent, size, op->op1_def, op->op1_use);
          }
        }
        if (opline->opcode == ZEND_ASSIGN && op->op2_use >= 0) {
          union_find_unite(parent, size, op->op1_def, op->op2_use);
        }
      }
      if (op->op2_def >= 0) {
        if (op->op2_use >= 0) {
          union_find_unite(parent, size, op->op2_def, op->op2_use);
        }
      }
      if (op->result_def >= 0) {
        if (op->result_use >= 0) {
          if (opline->opcode != ZEND_QM_ASSIGN) {
            union_find_unite(parent, size, op->result_def, op->result_use);
          }
        }
        if (opline->opcode == ZEND_QM_ASSIGN && op->op1_use >= 0) {
          union_find_unite(parent, size, op->result_def, op->op1_use);
        }
        if (opline->opcode == ZEND_ASSIGN && op->op2_use >= 0) {
          union_find_unite(parent, size, op->result_def, op->op2_use);
        }
        if (opline->opcode == ZEND_ASSIGN && op->op1_def >= 0) {
          union_find_unite(parent, size, op->result_def, op->op1_def);
        }
      }
    }
  }

  for (i = 0; i < ssa_vars_count; i++) {
    parent[i] = union_find_root(parent, i);
  }

  free_alloca(size, use_heap);

  return SUCCESS;
}
/* }}} */

static bool is_allocation_def(zend_op_array *op_array, zend_ssa *ssa, int def, int var, const zend_script *script) /* {{{ */
{
  zend_ssa_op *ssa_op = ssa->ops + def;
  zend_op *opline = op_array->opcodes + def;

  if (ssa_op->result_def == var) {
    switch (opline->opcode) {
      case ZEND_INIT_ARRAY:
        return true;
      case ZEND_NEW: {
          /* objects with destructors should escape */
        zend_class_entry *ce = zend_optimizer_get_class_entry_from_op1(
          script, op_array, opline);
        uint32_t forbidden_flags =
          /* These flags will always cause an exception */
          ZEND_ACC_IMPLICIT_ABSTRACT_CLASS | ZEND_ACC_EXPLICIT_ABSTRACT_CLASS
          | ZEND_ACC_INTERFACE | ZEND_ACC_TRAIT;
        if (ce
         && !ce->parent
         && !ce->create_object
         && ce->default_object_handlers->get_constructor == zend_std_get_constructor
         && ce->default_object_handlers->dtor_obj == zend_objects_destroy_object
         && !ce->constructor
         && !ce->destructor
         && !ce->__get
         && !ce->__set
         && !(ce->ce_flags & forbidden_flags)
         && (ce->ce_flags & ZEND_ACC_CONSTANTS_UPDATED)) {
          return true;
        }
        break;
      }
      case ZEND_QM_ASSIGN:
        if (opline->op1_type == IS_CONST
         && Z_TYPE_P(CRT_CONSTANT(opline->op1)) == IS_ARRAY) {
          return true;
        }
        if (opline->op1_type == IS_CV && (OP1_INFO() & MAY_BE_ARRAY)) {
          return true;
        }
        break;
      case ZEND_ASSIGN:
        if (opline->op1_type == IS_CV && (OP1_INFO() & MAY_BE_ARRAY)) {
          return true;
        }
        break;
    }
  } else if (ssa_op->op1_def == var) {
    switch (opline->opcode) {
      case ZEND_ASSIGN:
        if (opline->op2_type == IS_CONST
         && Z_TYPE_P(CRT_CONSTANT(opline->op2)) == IS_ARRAY) {
          return true;
        }
        if (opline->op2_type == IS_CV && (OP2_INFO() & MAY_BE_ARRAY)) {
          return true;
        }
        break;
      case ZEND_ASSIGN_DIM:
        if (OP1_INFO() & (MAY_BE_UNDEF | MAY_BE_NULL | MAY_BE_FALSE)) {
          /* implicit object/array allocation */
          return true;
        }
        break;
    }
  }

  return false;
}
/* }}} */

static bool is_local_def(zend_op_array *op_array, zend_ssa *ssa, int def, int var, const zend_script *script) /* {{{ */
{
  zend_ssa_op *op = ssa->ops + def;
  zend_op *opline = op_array->opcodes + def;

  if (op->result_def == var) {
    switch (opline->opcode) {
      case ZEND_INIT_ARRAY:
      case ZEND_ADD_ARRAY_ELEMENT:
      case ZEND_QM_ASSIGN:
      case ZEND_ASSIGN:
        return true;
      case ZEND_NEW: {
        /* objects with destructors should escape */
        zend_class_entry *ce = zend_optimizer_get_class_entry_from_op1(
          script, op_array, opline);
        if (ce
         && !ce->create_object
         && ce->default_object_handlers->get_constructor == zend_std_get_constructor
         && ce->default_object_handlers->dtor_obj == zend_objects_destroy_object
         && !ce->constructor
         && !ce->destructor
         && !ce->__get
         && !ce->__set
         && !ce->parent) {
          return true;
        }
        break;
      }
    }
  } else if (op->op1_def == var) {
    switch (opline->opcode) {
      case ZEND_ASSIGN:
      case ZEND_ASSIGN_DIM:
      case ZEND_ASSIGN_OBJ:
      case ZEND_ASSIGN_OBJ_REF:
      case ZEND_ASSIGN_DIM_OP:
      case ZEND_ASSIGN_OBJ_OP:
      case ZEND_PRE_INC_OBJ:
      case ZEND_PRE_DEC_OBJ:
      case ZEND_POST_INC_OBJ:
      case ZEND_POST_DEC_OBJ:
        return true;
    }
  }

  return false;
}
/* }}} */

static bool is_escape_use(zend_op_array *op_array, zend_ssa *ssa, int use, int var) /* {{{ */
{
  zend_ssa_op *ssa_op = ssa->ops + use;
  zend_op *opline = op_array->opcodes + use;

  if (ssa_op->op1_use == var) {
    switch (opline->opcode) {
      case ZEND_ASSIGN:
        /* no_val */
        break;
      case ZEND_QM_ASSIGN:
        if (opline->op1_type == IS_CV) {
          if (OP1_INFO() & MAY_BE_OBJECT) {
            /* object aliasing */
            return true;
          }
        }
        break;
      case ZEND_ISSET_ISEMPTY_DIM_OBJ:
      case ZEND_ISSET_ISEMPTY_PROP_OBJ:
      case ZEND_FETCH_DIM_R:
      case ZEND_FETCH_OBJ_R:
      case ZEND_FETCH_DIM_IS:
      case ZEND_FETCH_OBJ_IS:
        break;
      case ZEND_ASSIGN_OP:
        return true;
      case ZEND_ASSIGN_DIM_OP:
      case ZEND_ASSIGN_OBJ_OP:
      case ZEND_ASSIGN_STATIC_PROP_OP:
      case ZEND_ASSIGN_DIM:
      case ZEND_ASSIGN_OBJ:
      case ZEND_ASSIGN_OBJ_REF:
        break;
      case ZEND_PRE_INC_OBJ:
      case ZEND_PRE_DEC_OBJ:
      case ZEND_POST_INC_OBJ:
      case ZEND_POST_DEC_OBJ:
        break;
      case ZEND_INIT_ARRAY:
      case ZEND_ADD_ARRAY_ELEMENT:
        if (opline->extended_value & ZEND_ARRAY_ELEMENT_REF) {
          return true;
        }
        if (OP1_INFO() & MAY_BE_OBJECT) {
          /* object aliasing */
          return true;
        }
        /* reference dependencies processed separately */
        break;
      case ZEND_OP_DATA:
        if ((opline-1)->opcode != ZEND_ASSIGN_DIM
         && (opline-1)->opcode != ZEND_ASSIGN_OBJ) {
          return true;
        }
        if (OP1_INFO() & MAY_BE_OBJECT) {
          /* object aliasing */
          return true;
        }
        opline--;
        ssa_op--;
        if (opline->op1_type != IS_CV
         || (OP1_INFO() & MAY_BE_REF)
         || (ssa_op->op1_def >= 0 && ssa->vars[ssa_op->op1_def].alias)) {
          /* assignment into escaping structure */
          return true;
        }
        /* reference dependencies processed separately */
        break;
      default:
        return true;
    }
  }

  if (ssa_op->op2_use == var) {
    switch (opline->opcode) {
      case ZEND_ASSIGN:
        if (opline->op1_type != IS_CV
         || (OP1_INFO() & MAY_BE_REF)
         || (ssa_op->op1_def >= 0 && ssa->vars[ssa_op->op1_def].alias)) {
          /* assignment into escaping variable */
          return true;
        }
        if (opline->op2_type == IS_CV || opline->result_type != IS_UNUSED) {
          if (OP2_INFO() & MAY_BE_OBJECT) {
            /* object aliasing */
            return true;
          }
        }
        break;
      default:
        return true;
    }
  }

  if (ssa_op->result_use == var) {
    switch (opline->opcode) {
      case ZEND_ASSIGN:
      case ZEND_QM_ASSIGN:
      case ZEND_INIT_ARRAY:
      case ZEND_ADD_ARRAY_ELEMENT:
        break;
      default:
        return true;
    }
  }

  return false;
}
/* }}} */

zend_result zend_ssa_escape_analysis(const zend_script *script, zend_op_array *op_array, zend_ssa *ssa) /* {{{ */
{
  zend_ssa_var *ssa_vars = ssa->vars;
  int ssa_vars_count = ssa->vars_count;
  int i, root, use;
  int *ees;
  bool has_allocations;
  int num_non_escaped;
  ALLOCA_FLAG(use_heap)

  if (!ssa_vars) {
    return SUCCESS;
  }

  has_allocations = false;
  for (i = op_array->last_var; i < ssa_vars_count; i++) {
    if (ssa_vars[i].definition >= 0
      && (ssa->var_info[i].type & (MAY_BE_ARRAY|MAY_BE_OBJECT))
      && is_allocation_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
      has_allocations = true;
      break;
    }
  }
  if (!has_allocations) {
    return SUCCESS;
  }


  /* 1. Build EES (Equi-Escape Sets) */
  ees = do_alloca(sizeof(int) * ssa_vars_count, use_heap);
  if (!ees) {
    return FAILURE;
  }

  if (zend_build_equi_escape_sets(ees, op_array, ssa) == FAILURE) {
    free_alloca(ees, use_heap);
    return FAILURE;
  }

  /* 2. Identify Allocations */
  num_non_escaped = 0;
  for (i = op_array->last_var; i < ssa_vars_count; i++) {
    root = ees[i];
    if (ssa_vars[root].escape_state > ESCAPE_STATE_NO_ESCAPE) {
      /* already escape. skip */
    } else if (ssa_vars[i].alias && (ssa->var_info[i].type & MAY_BE_REF)) {
      if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
        num_non_escaped--;
      }
      ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
    } else if (ssa_vars[i].definition >= 0
       && (ssa->var_info[i].type & (MAY_BE_ARRAY|MAY_BE_OBJECT))) {
      if (!is_local_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
        if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
          num_non_escaped--;
        }
        ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
      } else if (ssa_vars[root].escape_state == ESCAPE_STATE_UNKNOWN
       && is_allocation_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
        ssa_vars[root].escape_state = ESCAPE_STATE_NO_ESCAPE;
        num_non_escaped++;
      }
    }
  }

  /* 3. Mark escaped EES */
  if (num_non_escaped) {
    for (i = 0; i < ssa_vars_count; i++) {
      if (ssa_vars[i].use_chain >= 0) {
        root = ees[i];
        if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
          FOREACH_USE(ssa_vars + i, use) {
            if (is_escape_use(op_array, ssa, use, i)) {
              ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
              num_non_escaped--;
              if (num_non_escaped == 0) {
                i = ssa_vars_count;
              }
              break;
            }
          } FOREACH_USE_END();
        }
      }
    }
  }

  /* 4. Process referential dependencies */
  if (num_non_escaped) {
    bool changed;

    do {
      changed = false;
      for (i = 0; i < ssa_vars_count; i++) {
        if (ssa_vars[i].use_chain >= 0) {
          root = ees[i];
          if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
            FOREACH_USE(ssa_vars + i, use) {
              zend_ssa_op *op = ssa->ops + use;
              zend_op *opline = op_array->opcodes + use;
              int enclosing_root;

              if (opline->opcode == ZEND_OP_DATA &&
                  ((opline-1)->opcode == ZEND_ASSIGN_DIM ||
                   (opline-1)->opcode == ZEND_ASSIGN_OBJ ||
                   (opline-1)->opcode == ZEND_ASSIGN_OBJ_REF) &&
                  op->op1_use == i &&
                  (op-1)->op1_use >= 0) {
                enclosing_root = ees[(op-1)->op1_use];
              } else if ((opline->opcode == ZEND_INIT_ARRAY ||
                   opline->opcode == ZEND_ADD_ARRAY_ELEMENT) &&
                  op->op1_use == i &&
                  op->result_def >= 0) {
                enclosing_root = ees[op->result_def];
              } else {
                continue;
              }

              if (ssa_vars[enclosing_root].escape_state == ESCAPE_STATE_UNKNOWN ||
                  ssa_vars[enclosing_root].escape_state > ssa_vars[root].escape_state) {
                  if (ssa_vars[enclosing_root].escape_state == ESCAPE_STATE_UNKNOWN) {
                  ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
                  } else {
                  ssa_vars[root].escape_state = ssa_vars[enclosing_root].escape_state;
                }
                if (ssa_vars[root].escape_state == ESCAPE_STATE_GLOBAL_ESCAPE) {
                  num_non_escaped--;
                  if (num_non_escaped == 0) {
                    changed = false;
                  } else {
                    changed = true;
                  }
                  break;
                } else {
                  changed = true;
                }
              }
            } FOREACH_USE_END();
          }
        }
      }
    } while (changed);
  }

  /* 5. Propagate values of escape sets to variables */
  for (i = 0; i < ssa_vars_count; i++) {
    root = ees[i];
    if (i != root) {
      ssa_vars[i].escape_state = ssa_vars[root].escape_state;
    }
  }

  free_alloca(ees, use_heap);

  return SUCCESS;
}
/* }}} */

Coverage Report

Created: 2025-12-14 06:06

Line	Count	Source
1		/*
2		+----------------------------------------------------------------------+
3		\| Zend OPcache, Escape Analysis \|
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: Dmitry Stogov <dmitry@php.net> \|
16		+----------------------------------------------------------------------+
17		*/
18
19		#include "Optimizer/zend_optimizer.h"
20		#include "Optimizer/zend_optimizer_internal.h"
21		#include "zend_bitset.h"
22		#include "zend_cfg.h"
23		#include "zend_ssa.h"
24		#include "zend_inference.h"
25		#include "zend_dump.h"
26
27		/*
28		* T. Kotzmann and H. Mossenbock. Escape analysis in the context of dynamic
29		* compilation and deoptimization. In Proceedings of the International
30		* Conference on Virtual Execution Environments, pages 111-120, Chicago,
31		* June 2005
32		*/
33
34		static zend_always_inline void union_find_init(int parent, int size, int count) /* {{{ */
35	0	{
36	0	int i;
37
38	0	for (i = 0; i < count; i++) {
39	0	parent[i] = i;
40	0	size[i] = 1;
41	0	}
42	0	}
43		/* }}} */
44
45		static zend_always_inline int union_find_root(int parent, int i) / {{{ */
46	0	{
47	0	int p = parent[i];
48
49	0	while (i != p) {
50	0	p = parent[p];
51	0	parent[i] = p;
52	0	i = p;
53	0	p = parent[i];
54	0	}
55	0	return i;
56	0	}
57		/* }}} */
58
59		static zend_always_inline void union_find_unite(int parent, int size, int i, int j) /* {{{ */
60	0	{
61	0	int r1 = union_find_root(parent, i);
62	0	int r2 = union_find_root(parent, j);
63
64	0	if (r1 != r2) {
65	0	if (size[r1] < size[r2]) {
66	0	parent[r1] = r2;
67	0	size[r2] += size[r1];
68	0	} else {
69	0	parent[r2] = r1;
70	0	size[r1] += size[r2];
71	0	}
72	0	}
73	0	}
74		/* }}} */
75
76		static zend_result zend_build_equi_escape_sets(int parent, zend_op_array op_array, zend_ssa ssa) / {{{ */
77	0	{
78	0	zend_ssa_var *ssa_vars = ssa->vars;
79	0	int ssa_vars_count = ssa->vars_count;
80	0	zend_ssa_phi *p;
81	0	int i, j;
82	0	int *size;
83	0	ALLOCA_FLAG(use_heap)
84
85	0	size = do_alloca(sizeof(int) * ssa_vars_count, use_heap);
86	0	if (!size) {
87	0	return FAILURE;
88	0	}
89	0	union_find_init(parent, size, ssa_vars_count);
90
91	0	for (i = 0; i < ssa_vars_count; i++) {
92	0	if (ssa_vars[i].definition_phi) {
93	0	p = ssa_vars[i].definition_phi;
94	0	if (p->pi >= 0) {
95	0	union_find_unite(parent, size, i, p->sources[0]);
96	0	} else {
97	0	for (j = 0; j < ssa->cfg.blocks[p->block].predecessors_count; j++) {
98	0	union_find_unite(parent, size, i, p->sources[j]);
99	0	}
100	0	}
101	0	} else if (ssa_vars[i].definition >= 0) {
102	0	int def = ssa_vars[i].definition;
103	0	zend_ssa_op *op = ssa->ops + def;
104	0	zend_op *opline = op_array->opcodes + def;
105
106	0	if (op->op1_def >= 0) {
107	0	if (op->op1_use >= 0) {
108	0	if (opline->opcode != ZEND_ASSIGN) {
109	0	union_find_unite(parent, size, op->op1_def, op->op1_use);
110	0	}
111	0	}
112	0	if (opline->opcode == ZEND_ASSIGN && op->op2_use >= 0) {
113	0	union_find_unite(parent, size, op->op1_def, op->op2_use);
114	0	}
115	0	}
116	0	if (op->op2_def >= 0) {
117	0	if (op->op2_use >= 0) {
118	0	union_find_unite(parent, size, op->op2_def, op->op2_use);
119	0	}
120	0	}
121	0	if (op->result_def >= 0) {
122	0	if (op->result_use >= 0) {
123	0	if (opline->opcode != ZEND_QM_ASSIGN) {
124	0	union_find_unite(parent, size, op->result_def, op->result_use);
125	0	}
126	0	}
127	0	if (opline->opcode == ZEND_QM_ASSIGN && op->op1_use >= 0) {
128	0	union_find_unite(parent, size, op->result_def, op->op1_use);
129	0	}
130	0	if (opline->opcode == ZEND_ASSIGN && op->op2_use >= 0) {
131	0	union_find_unite(parent, size, op->result_def, op->op2_use);
132	0	}
133	0	if (opline->opcode == ZEND_ASSIGN && op->op1_def >= 0) {
134	0	union_find_unite(parent, size, op->result_def, op->op1_def);
135	0	}
136	0	}
137	0	}
138	0	}
139
140	0	for (i = 0; i < ssa_vars_count; i++) {
141	0	parent[i] = union_find_root(parent, i);
142	0	}
143
144	0	free_alloca(size, use_heap);
145
146	0	return SUCCESS;
147	0	}
148		/* }}} */
149
150		static bool is_allocation_def(zend_op_array op_array, zend_ssa ssa, int def, int var, const zend_script script) / {{{ */
151	0	{
152	0	zend_ssa_op *ssa_op = ssa->ops + def;
153	0	zend_op *opline = op_array->opcodes + def;
154
155	0	if (ssa_op->result_def == var) {
156	0	switch (opline->opcode) {
157	0	case ZEND_INIT_ARRAY:
158	0	return true;
159	0	case ZEND_NEW: {
160		/* objects with destructors should escape */
161	0	zend_class_entry *ce = zend_optimizer_get_class_entry_from_op1(
162	0	script, op_array, opline);
163	0	uint32_t forbidden_flags =
164		/* These flags will always cause an exception */
165	0	ZEND_ACC_IMPLICIT_ABSTRACT_CLASS \| ZEND_ACC_EXPLICIT_ABSTRACT_CLASS
166	0	\| ZEND_ACC_INTERFACE \| ZEND_ACC_TRAIT;
167	0	if (ce
168	0	&& !ce->parent
169	0	&& !ce->create_object
170	0	&& ce->default_object_handlers->get_constructor == zend_std_get_constructor
171	0	&& ce->default_object_handlers->dtor_obj == zend_objects_destroy_object
172	0	&& !ce->constructor
173	0	&& !ce->destructor
174	0	&& !ce->__get
175	0	&& !ce->__set
176	0	&& !(ce->ce_flags & forbidden_flags)
177	0	&& (ce->ce_flags & ZEND_ACC_CONSTANTS_UPDATED)) {
178	0	return true;
179	0	}
180	0	break;
181	0	}
182	0	case ZEND_QM_ASSIGN:
183	0	if (opline->op1_type == IS_CONST
184	0	&& Z_TYPE_P(CRT_CONSTANT(opline->op1)) == IS_ARRAY) {
185	0	return true;
186	0	}
187	0	if (opline->op1_type == IS_CV && (OP1_INFO() & MAY_BE_ARRAY)) {
188	0	return true;
189	0	}
190	0	break;
191	0	case ZEND_ASSIGN:
192	0	if (opline->op1_type == IS_CV && (OP1_INFO() & MAY_BE_ARRAY)) {
193	0	return true;
194	0	}
195	0	break;
196	0	}
197	0	} else if (ssa_op->op1_def == var) {
198	0	switch (opline->opcode) {
199	0	case ZEND_ASSIGN:
200	0	if (opline->op2_type == IS_CONST
201	0	&& Z_TYPE_P(CRT_CONSTANT(opline->op2)) == IS_ARRAY) {
202	0	return true;
203	0	}
204	0	if (opline->op2_type == IS_CV && (OP2_INFO() & MAY_BE_ARRAY)) {
205	0	return true;
206	0	}
207	0	break;
208	0	case ZEND_ASSIGN_DIM:
209	0	if (OP1_INFO() & (MAY_BE_UNDEF \| MAY_BE_NULL \| MAY_BE_FALSE)) {
210		/* implicit object/array allocation */
211	0	return true;
212	0	}
213	0	break;
214	0	}
215	0	}
216
217	0	return false;
218	0	}
219		/* }}} */
220
221		static bool is_local_def(zend_op_array op_array, zend_ssa ssa, int def, int var, const zend_script script) / {{{ */
222	0	{
223	0	zend_ssa_op *op = ssa->ops + def;
224	0	zend_op *opline = op_array->opcodes + def;
225
226	0	if (op->result_def == var) {
227	0	switch (opline->opcode) {
228	0	case ZEND_INIT_ARRAY:
229	0	case ZEND_ADD_ARRAY_ELEMENT:
230	0	case ZEND_QM_ASSIGN:
231	0	case ZEND_ASSIGN:
232	0	return true;
233	0	case ZEND_NEW: {
234		/* objects with destructors should escape */
235	0	zend_class_entry *ce = zend_optimizer_get_class_entry_from_op1(
236	0	script, op_array, opline);
237	0	if (ce
238	0	&& !ce->create_object
239	0	&& ce->default_object_handlers->get_constructor == zend_std_get_constructor
240	0	&& ce->default_object_handlers->dtor_obj == zend_objects_destroy_object
241	0	&& !ce->constructor
242	0	&& !ce->destructor
243	0	&& !ce->__get
244	0	&& !ce->__set
245	0	&& !ce->parent) {
246	0	return true;
247	0	}
248	0	break;
249	0	}
250	0	}
251	0	} else if (op->op1_def == var) {
252	0	switch (opline->opcode) {
253	0	case ZEND_ASSIGN:
254	0	case ZEND_ASSIGN_DIM:
255	0	case ZEND_ASSIGN_OBJ:
256	0	case ZEND_ASSIGN_OBJ_REF:
257	0	case ZEND_ASSIGN_DIM_OP:
258	0	case ZEND_ASSIGN_OBJ_OP:
259	0	case ZEND_PRE_INC_OBJ:
260	0	case ZEND_PRE_DEC_OBJ:
261	0	case ZEND_POST_INC_OBJ:
262	0	case ZEND_POST_DEC_OBJ:
263	0	return true;
264	0	}
265	0	}
266
267	0	return false;
268	0	}
269		/* }}} */
270
271		static bool is_escape_use(zend_op_array op_array, zend_ssa ssa, int use, int var) /* {{{ */
272	0	{
273	0	zend_ssa_op *ssa_op = ssa->ops + use;
274	0	zend_op *opline = op_array->opcodes + use;
275
276	0	if (ssa_op->op1_use == var) {
277	0	switch (opline->opcode) {
278	0	case ZEND_ASSIGN:
279		/* no_val */
280	0	break;
281	0	case ZEND_QM_ASSIGN:
282	0	if (opline->op1_type == IS_CV) {
283	0	if (OP1_INFO() & MAY_BE_OBJECT) {
284		/* object aliasing */
285	0	return true;
286	0	}
287	0	}
288	0	break;
289	0	case ZEND_ISSET_ISEMPTY_DIM_OBJ:
290	0	case ZEND_ISSET_ISEMPTY_PROP_OBJ:
291	0	case ZEND_FETCH_DIM_R:
292	0	case ZEND_FETCH_OBJ_R:
293	0	case ZEND_FETCH_DIM_IS:
294	0	case ZEND_FETCH_OBJ_IS:
295	0	break;
296	0	case ZEND_ASSIGN_OP:
297	0	return true;
298	0	case ZEND_ASSIGN_DIM_OP:
299	0	case ZEND_ASSIGN_OBJ_OP:
300	0	case ZEND_ASSIGN_STATIC_PROP_OP:
301	0	case ZEND_ASSIGN_DIM:
302	0	case ZEND_ASSIGN_OBJ:
303	0	case ZEND_ASSIGN_OBJ_REF:
304	0	break;
305	0	case ZEND_PRE_INC_OBJ:
306	0	case ZEND_PRE_DEC_OBJ:
307	0	case ZEND_POST_INC_OBJ:
308	0	case ZEND_POST_DEC_OBJ:
309	0	break;
310	0	case ZEND_INIT_ARRAY:
311	0	case ZEND_ADD_ARRAY_ELEMENT:
312	0	if (opline->extended_value & ZEND_ARRAY_ELEMENT_REF) {
313	0	return true;
314	0	}
315	0	if (OP1_INFO() & MAY_BE_OBJECT) {
316		/* object aliasing */
317	0	return true;
318	0	}
319		/* reference dependencies processed separately */
320	0	break;
321	0	case ZEND_OP_DATA:
322	0	if ((opline-1)->opcode != ZEND_ASSIGN_DIM
323	0	&& (opline-1)->opcode != ZEND_ASSIGN_OBJ) {
324	0	return true;
325	0	}
326	0	if (OP1_INFO() & MAY_BE_OBJECT) {
327		/* object aliasing */
328	0	return true;
329	0	}
330	0	opline--;
331	0	ssa_op--;
332	0	if (opline->op1_type != IS_CV
333	0	\|\| (OP1_INFO() & MAY_BE_REF)
334	0	\|\| (ssa_op->op1_def >= 0 && ssa->vars[ssa_op->op1_def].alias)) {
335		/* assignment into escaping structure */
336	0	return true;
337	0	}
338		/* reference dependencies processed separately */
339	0	break;
340	0	default:
341	0	return true;
342	0	}
343	0	}
344
345	0	if (ssa_op->op2_use == var) {
346	0	switch (opline->opcode) {
347	0	case ZEND_ASSIGN:
348	0	if (opline->op1_type != IS_CV
349	0	\|\| (OP1_INFO() & MAY_BE_REF)
350	0	\|\| (ssa_op->op1_def >= 0 && ssa->vars[ssa_op->op1_def].alias)) {
351		/* assignment into escaping variable */
352	0	return true;
353	0	}
354	0	if (opline->op2_type == IS_CV \|\| opline->result_type != IS_UNUSED) {
355	0	if (OP2_INFO() & MAY_BE_OBJECT) {
356		/* object aliasing */
357	0	return true;
358	0	}
359	0	}
360	0	break;
361	0	default:
362	0	return true;
363	0	}
364	0	}
365
366	0	if (ssa_op->result_use == var) {
367	0	switch (opline->opcode) {
368	0	case ZEND_ASSIGN:
369	0	case ZEND_QM_ASSIGN:
370	0	case ZEND_INIT_ARRAY:
371	0	case ZEND_ADD_ARRAY_ELEMENT:
372	0	break;
373	0	default:
374	0	return true;
375	0	}
376	0	}
377
378	0	return false;
379	0	}
380		/* }}} */
381
382		zend_result zend_ssa_escape_analysis(const zend_script script, zend_op_array op_array, zend_ssa ssa) / {{{ */
383	0	{
384	0	zend_ssa_var *ssa_vars = ssa->vars;
385	0	int ssa_vars_count = ssa->vars_count;
386	0	int i, root, use;
387	0	int *ees;
388	0	bool has_allocations;
389	0	int num_non_escaped;
390	0	ALLOCA_FLAG(use_heap)
391
392	0	if (!ssa_vars) {
393	0	return SUCCESS;
394	0	}
395
396	0	has_allocations = false;
397	0	for (i = op_array->last_var; i < ssa_vars_count; i++) {
398	0	if (ssa_vars[i].definition >= 0
399	0	&& (ssa->var_info[i].type & (MAY_BE_ARRAY\|MAY_BE_OBJECT))
400	0	&& is_allocation_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
401	0	has_allocations = true;
402	0	break;
403	0	}
404	0	}
405	0	if (!has_allocations) {
406	0	return SUCCESS;
407	0	}
408
409
410		/* 1. Build EES (Equi-Escape Sets) */
411	0	ees = do_alloca(sizeof(int) * ssa_vars_count, use_heap);
412	0	if (!ees) {
413	0	return FAILURE;
414	0	}
415
416	0	if (zend_build_equi_escape_sets(ees, op_array, ssa) == FAILURE) {
417	0	free_alloca(ees, use_heap);
418	0	return FAILURE;
419	0	}
420
421		/* 2. Identify Allocations */
422	0	num_non_escaped = 0;
423	0	for (i = op_array->last_var; i < ssa_vars_count; i++) {
424	0	root = ees[i];
425	0	if (ssa_vars[root].escape_state > ESCAPE_STATE_NO_ESCAPE) {
426		/* already escape. skip */
427	0	} else if (ssa_vars[i].alias && (ssa->var_info[i].type & MAY_BE_REF)) {
428	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
429	0	num_non_escaped--;
430	0	}
431	0	ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
432	0	} else if (ssa_vars[i].definition >= 0
433	0	&& (ssa->var_info[i].type & (MAY_BE_ARRAY\|MAY_BE_OBJECT))) {
434	0	if (!is_local_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
435	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
436	0	num_non_escaped--;
437	0	}
438	0	ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
439	0	} else if (ssa_vars[root].escape_state == ESCAPE_STATE_UNKNOWN
440	0	&& is_allocation_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
441	0	ssa_vars[root].escape_state = ESCAPE_STATE_NO_ESCAPE;
442	0	num_non_escaped++;
443	0	}
444	0	}
445	0	}
446
447		/* 3. Mark escaped EES */
448	0	if (num_non_escaped) {
449	0	for (i = 0; i < ssa_vars_count; i++) {
450	0	if (ssa_vars[i].use_chain >= 0) {
451	0	root = ees[i];
452	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
453	0	FOREACH_USE(ssa_vars + i, use) {
454	0	if (is_escape_use(op_array, ssa, use, i)) {
455	0	ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
456	0	num_non_escaped--;
457	0	if (num_non_escaped == 0) {
458	0	i = ssa_vars_count;
459	0	}
460	0	break;
461	0	}
462	0	} FOREACH_USE_END();
463	0	}
464	0	}
465	0	}
466	0	}
467
468		/* 4. Process referential dependencies */
469	0	if (num_non_escaped) {
470	0	bool changed;
471
472	0	do {
473	0	changed = false;
474	0	for (i = 0; i < ssa_vars_count; i++) {
475	0	if (ssa_vars[i].use_chain >= 0) {
476	0	root = ees[i];
477	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
478	0	FOREACH_USE(ssa_vars + i, use) {
479	0	zend_ssa_op *op = ssa->ops + use;
480	0	zend_op *opline = op_array->opcodes + use;
481	0	int enclosing_root;
482
483	0	if (opline->opcode == ZEND_OP_DATA &&
484	0	((opline-1)->opcode == ZEND_ASSIGN_DIM \|\|
485	0	(opline-1)->opcode == ZEND_ASSIGN_OBJ \|\|
486	0	(opline-1)->opcode == ZEND_ASSIGN_OBJ_REF) &&
487	0	op->op1_use == i &&
488	0	(op-1)->op1_use >= 0) {
489	0	enclosing_root = ees[(op-1)->op1_use];
490	0	} else if ((opline->opcode == ZEND_INIT_ARRAY \|\|
491	0	opline->opcode == ZEND_ADD_ARRAY_ELEMENT) &&
492	0	op->op1_use == i &&
493	0	op->result_def >= 0) {
494	0	enclosing_root = ees[op->result_def];
495	0	} else {
496	0	continue;
497	0	}
498
499	0	if (ssa_vars[enclosing_root].escape_state == ESCAPE_STATE_UNKNOWN \|\|
500	0	ssa_vars[enclosing_root].escape_state > ssa_vars[root].escape_state) {
501	0	if (ssa_vars[enclosing_root].escape_state == ESCAPE_STATE_UNKNOWN) {
502	0	ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
503	0	} else {
504	0	ssa_vars[root].escape_state = ssa_vars[enclosing_root].escape_state;
505	0	}
506	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_GLOBAL_ESCAPE) {
507	0	num_non_escaped--;
508	0	if (num_non_escaped == 0) {
509	0	changed = false;
510	0	} else {
511	0	changed = true;
512	0	}
513	0	break;
514	0	} else {
515	0	changed = true;
516	0	}
517	0	}
518	0	} FOREACH_USE_END();
519	0	}
520	0	}
521	0	}
522	0	} while (changed);
523	0	}
524
525		/* 5. Propagate values of escape sets to variables */
526	0	for (i = 0; i < ssa_vars_count; i++) {
527	0	root = ees[i];
528	0	if (i != root) {
529	0	ssa_vars[i].escape_state = ssa_vars[root].escape_state;
530	0	}
531	0	}
532
533	0	free_alloca(ees, use_heap);
534
535	0	return SUCCESS;
536	0	}
537		/* }}} */