329 lines
12 KiB
C
329 lines
12 KiB
C
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/*
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+----------------------------------------------------------------------+
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| Zend Engine, SSA - Static Single Assignment Form |
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+----------------------------------------------------------------------+
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| Copyright (c) The PHP Group |
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+----------------------------------------------------------------------+
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| This source file is subject to version 3.01 of the PHP license, |
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| that is bundled with this package in the file LICENSE, and is |
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| available through the world-wide-web at the following url: |
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| https://www.php.net/license/3_01.txt |
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| If you did not receive a copy of the PHP license and are unable to |
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| obtain it through the world-wide-web, please send a note to |
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| license@php.net so we can mail you a copy immediately. |
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+----------------------------------------------------------------------+
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| Authors: Dmitry Stogov <dmitry@php.net> |
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+----------------------------------------------------------------------+
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*/
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#ifndef ZEND_SSA_H
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#define ZEND_SSA_H
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#include "zend_optimizer.h"
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#include "zend_cfg.h"
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typedef struct _zend_ssa_range {
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zend_long min;
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zend_long max;
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bool underflow;
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bool overflow;
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} zend_ssa_range;
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typedef enum _zend_ssa_negative_lat {
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NEG_NONE = 0,
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NEG_INIT = 1,
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NEG_INVARIANT = 2,
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NEG_USE_LT = 3,
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NEG_USE_GT = 4,
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NEG_UNKNOWN = 5
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} zend_ssa_negative_lat;
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/* Special kind of SSA Phi function used in eSSA */
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typedef struct _zend_ssa_range_constraint {
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zend_ssa_range range; /* simple range constraint */
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int min_var;
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int max_var;
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int min_ssa_var; /* ((min_var>0) ? MIN(ssa_var) : 0) + range.min */
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int max_ssa_var; /* ((max_var>0) ? MAX(ssa_var) : 0) + range.max */
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zend_ssa_negative_lat negative;
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} zend_ssa_range_constraint;
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typedef struct _zend_ssa_type_constraint {
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uint32_t type_mask; /* Type mask to intersect with */
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zend_class_entry *ce; /* Class entry for instanceof constraints */
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} zend_ssa_type_constraint;
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typedef union _zend_ssa_pi_constraint {
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zend_ssa_range_constraint range;
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zend_ssa_type_constraint type;
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} zend_ssa_pi_constraint;
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/* SSA Phi - ssa_var = Phi(source0, source1, ...sourceN) */
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typedef struct _zend_ssa_phi zend_ssa_phi;
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struct _zend_ssa_phi {
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zend_ssa_phi *next; /* next Phi in the same BB */
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int pi; /* if >= 0 this is actually a e-SSA Pi */
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zend_ssa_pi_constraint constraint; /* e-SSA Pi constraint */
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int var; /* Original CV, VAR or TMP variable index */
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int ssa_var; /* SSA variable index */
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int block; /* current BB index */
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bool has_range_constraint : 1;
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zend_ssa_phi **use_chains;
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zend_ssa_phi *sym_use_chain;
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int *sources; /* Array of SSA IDs that produce this var.
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As many as this block has
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predecessors. */
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};
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typedef struct _zend_ssa_block {
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zend_ssa_phi *phis;
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} zend_ssa_block;
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typedef struct _zend_ssa_op {
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int op1_use;
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int op2_use;
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int result_use;
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int op1_def;
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int op2_def;
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int result_def;
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int op1_use_chain;
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int op2_use_chain;
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int res_use_chain;
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} zend_ssa_op;
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typedef enum _zend_ssa_alias_kind {
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NO_ALIAS,
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SYMTABLE_ALIAS,
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HTTP_RESPONSE_HEADER_ALIAS
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} zend_ssa_alias_kind;
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typedef enum _zend_ssa_escape_state {
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ESCAPE_STATE_UNKNOWN,
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ESCAPE_STATE_NO_ESCAPE,
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ESCAPE_STATE_FUNCTION_ESCAPE,
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ESCAPE_STATE_GLOBAL_ESCAPE
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} zend_ssa_escape_state;
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typedef struct _zend_ssa_var {
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int var; /* original var number; op.var for CVs and following numbers for VARs and TMP_VARs */
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int scc; /* strongly connected component */
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int definition; /* opcode that defines this value */
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int use_chain; /* uses of this value, linked through opN_use_chain */
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zend_ssa_phi *definition_phi; /* phi that defines this value */
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zend_ssa_phi *phi_use_chain; /* uses of this value in Phi, linked through use_chain */
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zend_ssa_phi *sym_use_chain; /* uses of this value in Pi constraints */
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unsigned int no_val : 1; /* value doesn't matter (used as op1 in ZEND_ASSIGN) */
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unsigned int scc_entry : 1;
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unsigned int alias : 2; /* value may be changed indirectly */
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unsigned int escape_state : 2;
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} zend_ssa_var;
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typedef struct _zend_ssa_var_info {
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uint32_t type; /* inferred type (see zend_inference.h) */
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bool has_range : 1;
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bool is_instanceof : 1; /* 0 - class == "ce", 1 - may be child of "ce" */
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bool recursive : 1;
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bool use_as_double : 1;
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bool delayed_fetch_this : 1;
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bool avoid_refcounting : 1;
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bool guarded_reference : 1;
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bool indirect_reference : 1; /* IS_INDIRECT returned by FETCH_DIM_W/FETCH_OBJ_W */
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zend_ssa_range range;
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zend_class_entry *ce;
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} zend_ssa_var_info;
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typedef struct _zend_ssa {
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zend_cfg cfg; /* control flow graph */
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int vars_count; /* number of SSA variables */
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int sccs; /* number of SCCs */
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zend_ssa_block *blocks; /* array of SSA blocks */
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zend_ssa_op *ops; /* array of SSA instructions */
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zend_ssa_var *vars; /* use/def chain of SSA variables */
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zend_ssa_var_info *var_info;
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} zend_ssa;
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BEGIN_EXTERN_C()
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ZEND_API zend_result zend_build_ssa(zend_arena **arena, const zend_script *script, const zend_op_array *op_array, uint32_t build_flags, zend_ssa *ssa);
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ZEND_API void zend_ssa_compute_use_def_chains(zend_arena **arena, const zend_op_array *op_array, zend_ssa *ssa);
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ZEND_API int zend_ssa_rename_op(const zend_op_array *op_array, const zend_op *opline, uint32_t k, uint32_t build_flags, int ssa_vars_count, zend_ssa_op *ssa_ops, int *var);
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void zend_ssa_unlink_use_chain(zend_ssa *ssa, int op, int var);
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void zend_ssa_replace_use_chain(zend_ssa *ssa, int op, int new_op, int var);
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void zend_ssa_remove_predecessor(zend_ssa *ssa, int from, int to);
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void zend_ssa_remove_defs_of_instr(zend_ssa *ssa, zend_ssa_op *ssa_op);
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void zend_ssa_remove_instr(zend_ssa *ssa, zend_op *opline, zend_ssa_op *ssa_op);
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void zend_ssa_remove_phi(zend_ssa *ssa, zend_ssa_phi *phi);
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void zend_ssa_remove_uses_of_var(zend_ssa *ssa, int var_num);
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void zend_ssa_remove_block(zend_op_array *op_array, zend_ssa *ssa, int b);
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void zend_ssa_rename_var_uses(zend_ssa *ssa, int old_var, int new_var, bool update_types);
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void zend_ssa_remove_block_from_cfg(zend_ssa *ssa, int b);
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static zend_always_inline void _zend_ssa_remove_def(zend_ssa_var *var)
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{
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ZEND_ASSERT(var->definition >= 0);
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ZEND_ASSERT(var->use_chain < 0);
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ZEND_ASSERT(!var->phi_use_chain);
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var->definition = -1;
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}
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static zend_always_inline void zend_ssa_remove_result_def(zend_ssa *ssa, zend_ssa_op *ssa_op)
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{
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zend_ssa_var *var = &ssa->vars[ssa_op->result_def];
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_zend_ssa_remove_def(var);
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ssa_op->result_def = -1;
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}
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static zend_always_inline void zend_ssa_remove_op1_def(zend_ssa *ssa, zend_ssa_op *ssa_op)
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{
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zend_ssa_var *var = &ssa->vars[ssa_op->op1_def];
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_zend_ssa_remove_def(var);
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ssa_op->op1_def = -1;
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}
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static zend_always_inline void zend_ssa_remove_op2_def(zend_ssa *ssa, zend_ssa_op *ssa_op)
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{
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zend_ssa_var *var = &ssa->vars[ssa_op->op2_def];
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_zend_ssa_remove_def(var);
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ssa_op->op2_def = -1;
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}
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END_EXTERN_C()
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static zend_always_inline int zend_ssa_next_use(const zend_ssa_op *ssa_op, int var, int use)
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{
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ssa_op += use;
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if (ssa_op->op1_use == var) {
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return ssa_op->op1_use_chain;
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} else if (ssa_op->op2_use == var) {
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return ssa_op->op2_use_chain;
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} else {
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return ssa_op->res_use_chain;
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}
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}
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static zend_always_inline zend_ssa_phi* zend_ssa_next_use_phi(const zend_ssa *ssa, int var, const zend_ssa_phi *p)
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{
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if (p->pi >= 0) {
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return p->use_chains[0];
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} else {
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int j;
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for (j = 0; j < ssa->cfg.blocks[p->block].predecessors_count; j++) {
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if (p->sources[j] == var) {
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return p->use_chains[j];
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}
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}
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}
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return NULL;
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}
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static zend_always_inline bool zend_ssa_is_no_val_use(const zend_op *opline, const zend_ssa_op *ssa_op, int var)
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{
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if (opline->opcode == ZEND_ASSIGN
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|| opline->opcode == ZEND_UNSET_CV
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|| opline->opcode == ZEND_BIND_GLOBAL
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|| opline->opcode == ZEND_BIND_STATIC) {
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return ssa_op->op1_use == var && ssa_op->op2_use != var;
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}
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if (opline->opcode == ZEND_FE_FETCH_R || opline->opcode == ZEND_FE_FETCH_RW) {
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return ssa_op->op2_use == var && ssa_op->op1_use != var;
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}
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if (ssa_op->result_use == var
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&& opline->opcode != ZEND_ADD_ARRAY_ELEMENT
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&& opline->opcode != ZEND_ADD_ARRAY_UNPACK) {
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return ssa_op->op1_use != var && ssa_op->op2_use != var;
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}
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return 0;
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}
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static zend_always_inline void zend_ssa_rename_defs_of_instr(zend_ssa *ssa, zend_ssa_op *ssa_op) {
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/* Rename def to use if possible. Mark variable as not defined otherwise. */
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if (ssa_op->op1_def >= 0) {
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if (ssa_op->op1_use >= 0) {
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zend_ssa_rename_var_uses(ssa, ssa_op->op1_def, ssa_op->op1_use, 1);
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}
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ssa->vars[ssa_op->op1_def].definition = -1;
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ssa_op->op1_def = -1;
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}
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if (ssa_op->op2_def >= 0) {
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if (ssa_op->op2_use >= 0) {
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zend_ssa_rename_var_uses(ssa, ssa_op->op2_def, ssa_op->op2_use, 1);
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}
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ssa->vars[ssa_op->op2_def].definition = -1;
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ssa_op->op2_def = -1;
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}
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if (ssa_op->result_def >= 0) {
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if (ssa_op->result_use >= 0) {
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zend_ssa_rename_var_uses(ssa, ssa_op->result_def, ssa_op->result_use, 1);
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}
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ssa->vars[ssa_op->result_def].definition = -1;
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ssa_op->result_def = -1;
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}
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}
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#define NUM_PHI_SOURCES(phi) \
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((phi)->pi >= 0 ? 1 : (ssa->cfg.blocks[(phi)->block].predecessors_count))
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/* FOREACH_USE and FOREACH_PHI_USE explicitly support "continue"
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* and changing the use chain of the current element */
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#define FOREACH_USE(var, use) do { \
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int _var_num = (var) - ssa->vars, next; \
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for (use = (var)->use_chain; use >= 0; use = next) { \
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next = zend_ssa_next_use(ssa->ops, _var_num, use);
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#define FOREACH_USE_END() \
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} \
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} while (0)
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#define FOREACH_PHI_USE(var, phi) do { \
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int _var_num = (var) - ssa->vars; \
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zend_ssa_phi *next_phi; \
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for (phi = (var)->phi_use_chain; phi; phi = next_phi) { \
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next_phi = zend_ssa_next_use_phi(ssa, _var_num, phi);
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#define FOREACH_PHI_USE_END() \
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} \
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} while (0)
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#define FOREACH_PHI_SOURCE(phi, source) do { \
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zend_ssa_phi *_phi = (phi); \
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int _i, _end = NUM_PHI_SOURCES(phi); \
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for (_i = 0; _i < _end; _i++) { \
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ZEND_ASSERT(_phi->sources[_i] >= 0); \
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source = _phi->sources[_i];
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#define FOREACH_PHI_SOURCE_END() \
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} \
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} while (0)
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#define FOREACH_PHI(phi) do { \
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int _i; \
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for (_i = 0; _i < ssa->cfg.blocks_count; _i++) { \
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phi = ssa->blocks[_i].phis; \
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for (; phi; phi = phi->next) {
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#define FOREACH_PHI_END() \
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} \
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} \
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} while (0)
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#define FOREACH_BLOCK(block) do { \
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int _i; \
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for (_i = 0; _i < ssa->cfg.blocks_count; _i++) { \
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(block) = &ssa->cfg.blocks[_i]; \
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if (!((block)->flags & ZEND_BB_REACHABLE)) { \
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continue; \
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}
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#define FOREACH_BLOCK_END() \
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||
|
|
} \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
/* Does not support "break" */
|
||
|
|
#define FOREACH_INSTR_NUM(i) do { \
|
||
|
|
zend_basic_block *_block; \
|
||
|
|
FOREACH_BLOCK(_block) { \
|
||
|
|
uint32_t _end = _block->start + _block->len; \
|
||
|
|
for ((i) = _block->start; (i) < _end; (i)++) {
|
||
|
|
#define FOREACH_INSTR_NUM_END() \
|
||
|
|
} \
|
||
|
|
} FOREACH_BLOCK_END(); \
|
||
|
|
} while (0)
|
||
|
|
|
||
|
|
#endif /* ZEND_SSA_H */
|