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

Source
/*
   +----------------------------------------------------------------------+
   | Zend OPcache, Escape Analysis                                        |
   +----------------------------------------------------------------------+
   | 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: 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;
  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 (uint32_t 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: 2026-06-02 06:36

Line	Count	Source
1		/*
2		+----------------------------------------------------------------------+
3		\| Zend OPcache, Escape Analysis \|
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: Dmitry Stogov <dmitry@php.net> \|
14		+----------------------------------------------------------------------+
15		*/
16
17		#include "Optimizer/zend_optimizer.h"
18		#include "Optimizer/zend_optimizer_internal.h"
19		#include "zend_bitset.h"
20		#include "zend_cfg.h"
21		#include "zend_ssa.h"
22		#include "zend_inference.h"
23		#include "zend_dump.h"
24
25		/*
26		* T. Kotzmann and H. Mossenbock. Escape analysis in the context of dynamic
27		* compilation and deoptimization. In Proceedings of the International
28		* Conference on Virtual Execution Environments, pages 111-120, Chicago,
29		* June 2005
30		*/
31
32		static zend_always_inline void union_find_init(int parent, int size, int count) /* {{{ */
33	0	{
34	0	int i;
35
36	0	for (i = 0; i < count; i++) {
37	0	parent[i] = i;
38	0	size[i] = 1;
39	0	}
40	0	}
41		/* }}} */
42
43		static zend_always_inline int union_find_root(int parent, int i) / {{{ */
44	0	{
45	0	int p = parent[i];
46
47	0	while (i != p) {
48	0	p = parent[p];
49	0	parent[i] = p;
50	0	i = p;
51	0	p = parent[i];
52	0	}
53	0	return i;
54	0	}
55		/* }}} */
56
57		static zend_always_inline void union_find_unite(int parent, int size, int i, int j) /* {{{ */
58	0	{
59	0	int r1 = union_find_root(parent, i);
60	0	int r2 = union_find_root(parent, j);
61
62	0	if (r1 != r2) {
63	0	if (size[r1] < size[r2]) {
64	0	parent[r1] = r2;
65	0	size[r2] += size[r1];
66	0	} else {
67	0	parent[r2] = r1;
68	0	size[r1] += size[r2];
69	0	}
70	0	}
71	0	}
72		/* }}} */
73
74		static zend_result zend_build_equi_escape_sets(int parent, zend_op_array op_array, zend_ssa ssa) / {{{ */
75	0	{
76	0	zend_ssa_var *ssa_vars = ssa->vars;
77	0	int ssa_vars_count = ssa->vars_count;
78	0	zend_ssa_phi *p;
79	0	int i;
80	0	int *size;
81	0	ALLOCA_FLAG(use_heap)
82
83	0	size = do_alloca(sizeof(int) * ssa_vars_count, use_heap);
84	0	if (!size) {
85	0	return FAILURE;
86	0	}
87	0	union_find_init(parent, size, ssa_vars_count);
88
89	0	for (i = 0; i < ssa_vars_count; i++) {
90	0	if (ssa_vars[i].definition_phi) {
91	0	p = ssa_vars[i].definition_phi;
92	0	if (p->pi >= 0) {
93	0	union_find_unite(parent, size, i, p->sources[0]);
94	0	} else {
95	0	for (uint32_t j = 0; j < ssa->cfg.blocks[p->block].predecessors_count; j++) {
96	0	union_find_unite(parent, size, i, p->sources[j]);
97	0	}
98	0	}
99	0	} else if (ssa_vars[i].definition >= 0) {
100	0	int def = ssa_vars[i].definition;
101	0	zend_ssa_op *op = ssa->ops + def;
102	0	zend_op *opline = op_array->opcodes + def;
103
104	0	if (op->op1_def >= 0) {
105	0	if (op->op1_use >= 0) {
106	0	if (opline->opcode != ZEND_ASSIGN) {
107	0	union_find_unite(parent, size, op->op1_def, op->op1_use);
108	0	}
109	0	}
110	0	if (opline->opcode == ZEND_ASSIGN && op->op2_use >= 0) {
111	0	union_find_unite(parent, size, op->op1_def, op->op2_use);
112	0	}
113	0	}
114	0	if (op->op2_def >= 0) {
115	0	if (op->op2_use >= 0) {
116	0	union_find_unite(parent, size, op->op2_def, op->op2_use);
117	0	}
118	0	}
119	0	if (op->result_def >= 0) {
120	0	if (op->result_use >= 0) {
121	0	if (opline->opcode != ZEND_QM_ASSIGN) {
122	0	union_find_unite(parent, size, op->result_def, op->result_use);
123	0	}
124	0	}
125	0	if (opline->opcode == ZEND_QM_ASSIGN && op->op1_use >= 0) {
126	0	union_find_unite(parent, size, op->result_def, op->op1_use);
127	0	}
128	0	if (opline->opcode == ZEND_ASSIGN && op->op2_use >= 0) {
129	0	union_find_unite(parent, size, op->result_def, op->op2_use);
130	0	}
131	0	if (opline->opcode == ZEND_ASSIGN && op->op1_def >= 0) {
132	0	union_find_unite(parent, size, op->result_def, op->op1_def);
133	0	}
134	0	}
135	0	}
136	0	}
137
138	0	for (i = 0; i < ssa_vars_count; i++) {
139	0	parent[i] = union_find_root(parent, i);
140	0	}
141
142	0	free_alloca(size, use_heap);
143
144	0	return SUCCESS;
145	0	}
146		/* }}} */
147
148		static bool is_allocation_def(zend_op_array op_array, zend_ssa ssa, int def, int var, const zend_script script) / {{{ */
149	0	{
150	0	zend_ssa_op *ssa_op = ssa->ops + def;
151	0	zend_op *opline = op_array->opcodes + def;
152
153	0	if (ssa_op->result_def == var) {
154	0	switch (opline->opcode) {
155	0	case ZEND_INIT_ARRAY:
156	0	return true;
157	0	case ZEND_NEW: {
158		/* objects with destructors should escape */
159	0	zend_class_entry *ce = zend_optimizer_get_class_entry_from_op1(
160	0	script, op_array, opline);
161	0	uint32_t forbidden_flags =
162		/* These flags will always cause an exception */
163	0	ZEND_ACC_IMPLICIT_ABSTRACT_CLASS \| ZEND_ACC_EXPLICIT_ABSTRACT_CLASS
164	0	\| ZEND_ACC_INTERFACE \| ZEND_ACC_TRAIT;
165	0	if (ce
166	0	&& !ce->parent
167	0	&& !ce->create_object
168	0	&& ce->default_object_handlers->get_constructor == zend_std_get_constructor
169	0	&& ce->default_object_handlers->dtor_obj == zend_objects_destroy_object
170	0	&& !ce->constructor
171	0	&& !ce->destructor
172	0	&& !ce->__get
173	0	&& !ce->__set
174	0	&& !(ce->ce_flags & forbidden_flags)
175	0	&& (ce->ce_flags & ZEND_ACC_CONSTANTS_UPDATED)) {
176	0	return true;
177	0	}
178	0	break;
179	0	}
180	0	case ZEND_QM_ASSIGN:
181	0	if (opline->op1_type == IS_CONST
182	0	&& Z_TYPE_P(CRT_CONSTANT(opline->op1)) == IS_ARRAY) {
183	0	return true;
184	0	}
185	0	if (opline->op1_type == IS_CV && (OP1_INFO() & MAY_BE_ARRAY)) {
186	0	return true;
187	0	}
188	0	break;
189	0	case ZEND_ASSIGN:
190	0	if (opline->op1_type == IS_CV && (OP1_INFO() & MAY_BE_ARRAY)) {
191	0	return true;
192	0	}
193	0	break;
194	0	}
195	0	} else if (ssa_op->op1_def == var) {
196	0	switch (opline->opcode) {
197	0	case ZEND_ASSIGN:
198	0	if (opline->op2_type == IS_CONST
199	0	&& Z_TYPE_P(CRT_CONSTANT(opline->op2)) == IS_ARRAY) {
200	0	return true;
201	0	}
202	0	if (opline->op2_type == IS_CV && (OP2_INFO() & MAY_BE_ARRAY)) {
203	0	return true;
204	0	}
205	0	break;
206	0	case ZEND_ASSIGN_DIM:
207	0	if (OP1_INFO() & (MAY_BE_UNDEF \| MAY_BE_NULL \| MAY_BE_FALSE)) {
208		/* implicit object/array allocation */
209	0	return true;
210	0	}
211	0	break;
212	0	}
213	0	}
214
215	0	return false;
216	0	}
217		/* }}} */
218
219		static bool is_local_def(zend_op_array op_array, zend_ssa ssa, int def, int var, const zend_script script) / {{{ */
220	0	{
221	0	zend_ssa_op *op = ssa->ops + def;
222	0	zend_op *opline = op_array->opcodes + def;
223
224	0	if (op->result_def == var) {
225	0	switch (opline->opcode) {
226	0	case ZEND_INIT_ARRAY:
227	0	case ZEND_ADD_ARRAY_ELEMENT:
228	0	case ZEND_QM_ASSIGN:
229	0	case ZEND_ASSIGN:
230	0	return true;
231	0	case ZEND_NEW: {
232		/* objects with destructors should escape */
233	0	zend_class_entry *ce = zend_optimizer_get_class_entry_from_op1(
234	0	script, op_array, opline);
235	0	if (ce
236	0	&& !ce->create_object
237	0	&& ce->default_object_handlers->get_constructor == zend_std_get_constructor
238	0	&& ce->default_object_handlers->dtor_obj == zend_objects_destroy_object
239	0	&& !ce->constructor
240	0	&& !ce->destructor
241	0	&& !ce->__get
242	0	&& !ce->__set
243	0	&& !ce->parent) {
244	0	return true;
245	0	}
246	0	break;
247	0	}
248	0	}
249	0	} else if (op->op1_def == var) {
250	0	switch (opline->opcode) {
251	0	case ZEND_ASSIGN:
252	0	case ZEND_ASSIGN_DIM:
253	0	case ZEND_ASSIGN_OBJ:
254	0	case ZEND_ASSIGN_OBJ_REF:
255	0	case ZEND_ASSIGN_DIM_OP:
256	0	case ZEND_ASSIGN_OBJ_OP:
257	0	case ZEND_PRE_INC_OBJ:
258	0	case ZEND_PRE_DEC_OBJ:
259	0	case ZEND_POST_INC_OBJ:
260	0	case ZEND_POST_DEC_OBJ:
261	0	return true;
262	0	}
263	0	}
264
265	0	return false;
266	0	}
267		/* }}} */
268
269		static bool is_escape_use(zend_op_array op_array, zend_ssa ssa, int use, int var) /* {{{ */
270	0	{
271	0	zend_ssa_op *ssa_op = ssa->ops + use;
272	0	zend_op *opline = op_array->opcodes + use;
273
274	0	if (ssa_op->op1_use == var) {
275	0	switch (opline->opcode) {
276	0	case ZEND_ASSIGN:
277		/* no_val */
278	0	break;
279	0	case ZEND_QM_ASSIGN:
280	0	if (opline->op1_type == IS_CV) {
281	0	if (OP1_INFO() & MAY_BE_OBJECT) {
282		/* object aliasing */
283	0	return true;
284	0	}
285	0	}
286	0	break;
287	0	case ZEND_ISSET_ISEMPTY_DIM_OBJ:
288	0	case ZEND_ISSET_ISEMPTY_PROP_OBJ:
289	0	case ZEND_FETCH_DIM_R:
290	0	case ZEND_FETCH_OBJ_R:
291	0	case ZEND_FETCH_DIM_IS:
292	0	case ZEND_FETCH_OBJ_IS:
293	0	break;
294	0	case ZEND_ASSIGN_OP:
295	0	return true;
296	0	case ZEND_ASSIGN_DIM_OP:
297	0	case ZEND_ASSIGN_OBJ_OP:
298	0	case ZEND_ASSIGN_STATIC_PROP_OP:
299	0	case ZEND_ASSIGN_DIM:
300	0	case ZEND_ASSIGN_OBJ:
301	0	case ZEND_ASSIGN_OBJ_REF:
302	0	break;
303	0	case ZEND_PRE_INC_OBJ:
304	0	case ZEND_PRE_DEC_OBJ:
305	0	case ZEND_POST_INC_OBJ:
306	0	case ZEND_POST_DEC_OBJ:
307	0	break;
308	0	case ZEND_INIT_ARRAY:
309	0	case ZEND_ADD_ARRAY_ELEMENT:
310	0	if (opline->extended_value & ZEND_ARRAY_ELEMENT_REF) {
311	0	return true;
312	0	}
313	0	if (OP1_INFO() & MAY_BE_OBJECT) {
314		/* object aliasing */
315	0	return true;
316	0	}
317		/* reference dependencies processed separately */
318	0	break;
319	0	case ZEND_OP_DATA:
320	0	if ((opline-1)->opcode != ZEND_ASSIGN_DIM
321	0	&& (opline-1)->opcode != ZEND_ASSIGN_OBJ) {
322	0	return true;
323	0	}
324	0	if (OP1_INFO() & MAY_BE_OBJECT) {
325		/* object aliasing */
326	0	return true;
327	0	}
328	0	opline--;
329	0	ssa_op--;
330	0	if (opline->op1_type != IS_CV
331	0	\|\| (OP1_INFO() & MAY_BE_REF)
332	0	\|\| (ssa_op->op1_def >= 0 && ssa->vars[ssa_op->op1_def].alias)) {
333		/* assignment into escaping structure */
334	0	return true;
335	0	}
336		/* reference dependencies processed separately */
337	0	break;
338	0	default:
339	0	return true;
340	0	}
341	0	}
342
343	0	if (ssa_op->op2_use == var) {
344	0	switch (opline->opcode) {
345	0	case ZEND_ASSIGN:
346	0	if (opline->op1_type != IS_CV
347	0	\|\| (OP1_INFO() & MAY_BE_REF)
348	0	\|\| (ssa_op->op1_def >= 0 && ssa->vars[ssa_op->op1_def].alias)) {
349		/* assignment into escaping variable */
350	0	return true;
351	0	}
352	0	if (opline->op2_type == IS_CV \|\| opline->result_type != IS_UNUSED) {
353	0	if (OP2_INFO() & MAY_BE_OBJECT) {
354		/* object aliasing */
355	0	return true;
356	0	}
357	0	}
358	0	break;
359	0	default:
360	0	return true;
361	0	}
362	0	}
363
364	0	if (ssa_op->result_use == var) {
365	0	switch (opline->opcode) {
366	0	case ZEND_ASSIGN:
367	0	case ZEND_QM_ASSIGN:
368	0	case ZEND_INIT_ARRAY:
369	0	case ZEND_ADD_ARRAY_ELEMENT:
370	0	break;
371	0	default:
372	0	return true;
373	0	}
374	0	}
375
376	0	return false;
377	0	}
378		/* }}} */
379
380		zend_result zend_ssa_escape_analysis(const zend_script script, zend_op_array op_array, zend_ssa ssa) / {{{ */
381	0	{
382	0	zend_ssa_var *ssa_vars = ssa->vars;
383	0	int ssa_vars_count = ssa->vars_count;
384	0	int i, root, use;
385	0	int *ees;
386	0	bool has_allocations;
387	0	int num_non_escaped;
388	0	ALLOCA_FLAG(use_heap)
389
390	0	if (!ssa_vars) {
391	0	return SUCCESS;
392	0	}
393
394	0	has_allocations = false;
395	0	for (i = op_array->last_var; i < ssa_vars_count; i++) {
396	0	if (ssa_vars[i].definition >= 0
397	0	&& (ssa->var_info[i].type & (MAY_BE_ARRAY\|MAY_BE_OBJECT))
398	0	&& is_allocation_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
399	0	has_allocations = true;
400	0	break;
401	0	}
402	0	}
403	0	if (!has_allocations) {
404	0	return SUCCESS;
405	0	}
406
407
408		/* 1. Build EES (Equi-Escape Sets) */
409	0	ees = do_alloca(sizeof(int) * ssa_vars_count, use_heap);
410	0	if (!ees) {
411	0	return FAILURE;
412	0	}
413
414	0	if (zend_build_equi_escape_sets(ees, op_array, ssa) == FAILURE) {
415	0	free_alloca(ees, use_heap);
416	0	return FAILURE;
417	0	}
418
419		/* 2. Identify Allocations */
420	0	num_non_escaped = 0;
421	0	for (i = op_array->last_var; i < ssa_vars_count; i++) {
422	0	root = ees[i];
423	0	if (ssa_vars[root].escape_state > ESCAPE_STATE_NO_ESCAPE) {
424		/* already escape. skip */
425	0	} else if (ssa_vars[i].alias && (ssa->var_info[i].type & MAY_BE_REF)) {
426	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
427	0	num_non_escaped--;
428	0	}
429	0	ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
430	0	} else if (ssa_vars[i].definition >= 0
431	0	&& (ssa->var_info[i].type & (MAY_BE_ARRAY\|MAY_BE_OBJECT))) {
432	0	if (!is_local_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
433	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
434	0	num_non_escaped--;
435	0	}
436	0	ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
437	0	} else if (ssa_vars[root].escape_state == ESCAPE_STATE_UNKNOWN
438	0	&& is_allocation_def(op_array, ssa, ssa_vars[i].definition, i, script)) {
439	0	ssa_vars[root].escape_state = ESCAPE_STATE_NO_ESCAPE;
440	0	num_non_escaped++;
441	0	}
442	0	}
443	0	}
444
445		/* 3. Mark escaped EES */
446	0	if (num_non_escaped) {
447	0	for (i = 0; i < ssa_vars_count; i++) {
448	0	if (ssa_vars[i].use_chain >= 0) {
449	0	root = ees[i];
450	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
451	0	FOREACH_USE(ssa_vars + i, use) {
452	0	if (is_escape_use(op_array, ssa, use, i)) {
453	0	ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
454	0	num_non_escaped--;
455	0	if (num_non_escaped == 0) {
456	0	i = ssa_vars_count;
457	0	}
458	0	break;
459	0	}
460	0	} FOREACH_USE_END();
461	0	}
462	0	}
463	0	}
464	0	}
465
466		/* 4. Process referential dependencies */
467	0	if (num_non_escaped) {
468	0	bool changed;
469
470	0	do {
471	0	changed = false;
472	0	for (i = 0; i < ssa_vars_count; i++) {
473	0	if (ssa_vars[i].use_chain >= 0) {
474	0	root = ees[i];
475	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_NO_ESCAPE) {
476	0	FOREACH_USE(ssa_vars + i, use) {
477	0	zend_ssa_op *op = ssa->ops + use;
478	0	zend_op *opline = op_array->opcodes + use;
479	0	int enclosing_root;
480
481	0	if (opline->opcode == ZEND_OP_DATA &&
482	0	((opline-1)->opcode == ZEND_ASSIGN_DIM \|\|
483	0	(opline-1)->opcode == ZEND_ASSIGN_OBJ \|\|
484	0	(opline-1)->opcode == ZEND_ASSIGN_OBJ_REF) &&
485	0	op->op1_use == i &&
486	0	(op-1)->op1_use >= 0) {
487	0	enclosing_root = ees[(op-1)->op1_use];
488	0	} else if ((opline->opcode == ZEND_INIT_ARRAY \|\|
489	0	opline->opcode == ZEND_ADD_ARRAY_ELEMENT) &&
490	0	op->op1_use == i &&
491	0	op->result_def >= 0) {
492	0	enclosing_root = ees[op->result_def];
493	0	} else {
494	0	continue;
495	0	}
496
497	0	if (ssa_vars[enclosing_root].escape_state == ESCAPE_STATE_UNKNOWN \|\|
498	0	ssa_vars[enclosing_root].escape_state > ssa_vars[root].escape_state) {
499	0	if (ssa_vars[enclosing_root].escape_state == ESCAPE_STATE_UNKNOWN) {
500	0	ssa_vars[root].escape_state = ESCAPE_STATE_GLOBAL_ESCAPE;
501	0	} else {
502	0	ssa_vars[root].escape_state = ssa_vars[enclosing_root].escape_state;
503	0	}
504	0	if (ssa_vars[root].escape_state == ESCAPE_STATE_GLOBAL_ESCAPE) {
505	0	num_non_escaped--;
506	0	if (num_non_escaped == 0) {
507	0	changed = false;
508	0	} else {
509	0	changed = true;
510	0	}
511	0	break;
512	0	} else {
513	0	changed = true;
514	0	}
515	0	}
516	0	} FOREACH_USE_END();
517	0	}
518	0	}
519	0	}
520	0	} while (changed);
521	0	}
522
523		/* 5. Propagate values of escape sets to variables */
524	0	for (i = 0; i < ssa_vars_count; i++) {
525	0	root = ees[i];
526	0	if (i != root) {
527	0	ssa_vars[i].escape_state = ssa_vars[root].escape_state;
528	0	}
529	0	}
530
531	0	free_alloca(ees, use_heap);
532
533	0	return SUCCESS;
534	0	}
535		/* }}} */