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dfa_pass.c
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/*
+----------------------------------------------------------------------+
| Zend OPcache |
+----------------------------------------------------------------------+
| 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 |
| [email protected] so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: Dmitry Stogov <[email protected]> |
+----------------------------------------------------------------------+
*/
#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"
#include "zend_bitset.h"
#include "zend_cfg.h"
#include "zend_ssa.h"
#include "zend_func_info.h"
#include "zend_call_graph.h"
#include "zend_inference.h"
#include "zend_dump.h"
// #ifndef ZEND_DEBUG_DFA
# define ZEND_DEBUG_DFA ZEND_DEBUG
// #endif
#if ZEND_DEBUG_DFA
# include "ssa_integrity.c"
#endif
zend_result zend_dfa_analyze_op_array(zend_op_array *op_array, zend_optimizer_ctx *ctx, zend_ssa *ssa)
{
uint32_t build_flags;
if (op_array->last_try_catch) {
/* TODO: we can't analyze functions with try/catch/finally ??? */
return FAILURE;
}
/* Build SSA */
memset(ssa, 0, sizeof(zend_ssa));
zend_build_cfg(&ctx->arena, op_array, ZEND_CFG_NO_ENTRY_PREDECESSORS, &ssa->cfg);
if ((ssa->cfg.flags & ZEND_FUNC_INDIRECT_VAR_ACCESS)) {
/* TODO: we can't analyze functions with indirect variable access ??? */
return FAILURE;
}
zend_cfg_build_predecessors(&ctx->arena, &ssa->cfg);
if (ctx->debug_level & ZEND_DUMP_DFA_CFG) {
zend_dump_op_array(op_array, ZEND_DUMP_CFG, "dfa cfg", &ssa->cfg);
}
/* Compute Dominators Tree */
zend_cfg_compute_dominators_tree(op_array, &ssa->cfg);
/* Identify reducible and irreducible loops */
zend_cfg_identify_loops(op_array, &ssa->cfg);
if (ctx->debug_level & ZEND_DUMP_DFA_DOMINATORS) {
zend_dump_dominators(op_array, &ssa->cfg);
}
build_flags = 0;
if (ctx->debug_level & ZEND_DUMP_DFA_LIVENESS) {
build_flags |= ZEND_SSA_DEBUG_LIVENESS;
}
if (ctx->debug_level & ZEND_DUMP_DFA_PHI) {
build_flags |= ZEND_SSA_DEBUG_PHI_PLACEMENT;
}
if (zend_build_ssa(&ctx->arena, ctx->script, op_array, build_flags, ssa) == FAILURE) {
return FAILURE;
}
if (ctx->debug_level & ZEND_DUMP_DFA_SSA) {
zend_dump_op_array(op_array, ZEND_DUMP_SSA, "dfa ssa", ssa);
}
zend_ssa_compute_use_def_chains(&ctx->arena, op_array, ssa);
zend_ssa_find_false_dependencies(op_array, ssa);
zend_ssa_find_sccs(op_array, ssa);
if (zend_ssa_inference(&ctx->arena, op_array, ctx->script, ssa, ctx->optimization_level) == FAILURE) {
return FAILURE;
}
if (zend_ssa_escape_analysis(ctx->script, op_array, ssa) == FAILURE) {
return FAILURE;
}
if (ctx->debug_level & ZEND_DUMP_DFA_SSA_VARS) {
zend_dump_ssa_variables(op_array, ssa, 0);
}
return SUCCESS;
}
static void zend_ssa_remove_nops(zend_op_array *op_array, zend_ssa *ssa, zend_optimizer_ctx *ctx)
{
zend_basic_block *blocks = ssa->cfg.blocks;
zend_basic_block *blocks_end = blocks + ssa->cfg.blocks_count;
zend_basic_block *b;
zend_func_info *func_info;
int j;
uint32_t i = 0;
uint32_t target = 0;
uint32_t *shiftlist;
ALLOCA_FLAG(use_heap);
shiftlist = (uint32_t *)do_alloca(sizeof(uint32_t) * op_array->last, use_heap);
memset(shiftlist, 0, sizeof(uint32_t) * op_array->last);
/* remove empty callee_info */
func_info = ZEND_FUNC_INFO(op_array);
if (func_info) {
zend_call_info **call_info = &func_info->callee_info;
while ((*call_info)) {
if ((*call_info)->caller_init_opline->opcode == ZEND_NOP) {
*call_info = (*call_info)->next_callee;
} else {
call_info = &(*call_info)->next_callee;
}
}
}
for (b = blocks; b < blocks_end; b++) {
if (b->flags & (ZEND_BB_REACHABLE|ZEND_BB_UNREACHABLE_FREE)) {
if (b->len) {
uint32_t new_start, old_end;
while (i < b->start) {
shiftlist[i] = i - target;
i++;
}
if (b->flags & ZEND_BB_UNREACHABLE_FREE) {
/* Only keep the FREE for the loop var */
ZEND_ASSERT(op_array->opcodes[b->start].opcode == ZEND_FREE
|| op_array->opcodes[b->start].opcode == ZEND_FE_FREE);
b->len = 1;
}
new_start = target;
old_end = b->start + b->len;
while (i < old_end) {
shiftlist[i] = i - target;
if (EXPECTED(op_array->opcodes[i].opcode != ZEND_NOP)) {
if (i != target) {
op_array->opcodes[target] = op_array->opcodes[i];
ssa->ops[target] = ssa->ops[i];
ssa->cfg.map[target] = b - blocks;
}
target++;
}
i++;
}
b->start = new_start;
if (target != old_end) {
zend_op *opline;
zend_op *new_opline;
b->len = target - b->start;
opline = op_array->opcodes + old_end - 1;
if (opline->opcode == ZEND_NOP) {
continue;
}
new_opline = op_array->opcodes + target - 1;
zend_optimizer_migrate_jump(op_array, new_opline, opline);
}
} else {
b->start = target;
}
} else {
b->start = target;
b->len = 0;
}
}
if (target != op_array->last) {
/* reset rest opcodes */
for (i = target; i < op_array->last; i++) {
MAKE_NOP(op_array->opcodes + i);
}
/* update SSA variables */
for (j = 0; j < ssa->vars_count; j++) {
if (ssa->vars[j].definition >= 0) {
ssa->vars[j].definition -= shiftlist[ssa->vars[j].definition];
}
if (ssa->vars[j].use_chain >= 0) {
ssa->vars[j].use_chain -= shiftlist[ssa->vars[j].use_chain];
}
}
for (i = 0; i < op_array->last; i++) {
if (ssa->ops[i].op1_use_chain >= 0) {
ssa->ops[i].op1_use_chain -= shiftlist[ssa->ops[i].op1_use_chain];
}
if (ssa->ops[i].op2_use_chain >= 0) {
ssa->ops[i].op2_use_chain -= shiftlist[ssa->ops[i].op2_use_chain];
}
if (ssa->ops[i].res_use_chain >= 0) {
ssa->ops[i].res_use_chain -= shiftlist[ssa->ops[i].res_use_chain];
}
}
/* update branch targets */
for (b = blocks; b < blocks_end; b++) {
if ((b->flags & ZEND_BB_REACHABLE) && b->len != 0) {
zend_op *opline = op_array->opcodes + b->start + b->len - 1;
zend_optimizer_shift_jump(op_array, opline, shiftlist);
}
}
/* update try/catch array */
for (j = 0; j < op_array->last_try_catch; j++) {
op_array->try_catch_array[j].try_op -= shiftlist[op_array->try_catch_array[j].try_op];
op_array->try_catch_array[j].catch_op -= shiftlist[op_array->try_catch_array[j].catch_op];
if (op_array->try_catch_array[j].finally_op) {
op_array->try_catch_array[j].finally_op -= shiftlist[op_array->try_catch_array[j].finally_op];
op_array->try_catch_array[j].finally_end -= shiftlist[op_array->try_catch_array[j].finally_end];
}
}
/* update call graph */
if (func_info) {
zend_call_info *call_info = func_info->callee_info;
while (call_info) {
call_info->caller_init_opline -=
shiftlist[call_info->caller_init_opline - op_array->opcodes];
if (call_info->caller_call_opline) {
call_info->caller_call_opline -=
shiftlist[call_info->caller_call_opline - op_array->opcodes];
}
call_info = call_info->next_callee;
}
}
op_array->last = target;
}
free_alloca(shiftlist, use_heap);
}
static bool safe_instanceof(zend_class_entry *ce1, zend_class_entry *ce2) {
if (ce1 == ce2) {
return 1;
}
if (!(ce1->ce_flags & ZEND_ACC_LINKED)) {
/* This case could be generalized, similarly to unlinked_instanceof */
return 0;
}
return instanceof_function(ce1, ce2);
}
static inline bool can_elide_list_type(
const zend_script *script, const zend_op_array *op_array,
const zend_ssa_var_info *use_info, zend_type type)
{
zend_type *single_type;
/* For intersection: result==false is failure, default is success.
* For union: result==true is success, default is failure. */
bool is_intersection = ZEND_TYPE_IS_INTERSECTION(type);
ZEND_TYPE_FOREACH(type, single_type) {
if (ZEND_TYPE_HAS_LIST(*single_type)) {
ZEND_ASSERT(!is_intersection);
return can_elide_list_type(script, op_array, use_info, *single_type);
}
if (ZEND_TYPE_HAS_NAME(*single_type)) {
zend_string *lcname = zend_string_tolower(ZEND_TYPE_NAME(*single_type));
zend_class_entry *ce = zend_optimizer_get_class_entry(script, op_array, lcname);
zend_string_release(lcname);
bool result = ce && safe_instanceof(use_info->ce, ce);
if (result == !is_intersection) {
return result;
}
}
} ZEND_TYPE_FOREACH_END();
return is_intersection;
}
static inline bool can_elide_return_type_check(
const zend_script *script, zend_op_array *op_array, zend_ssa *ssa, zend_ssa_op *ssa_op) {
zend_arg_info *arg_info = &op_array->arg_info[-1];
zend_ssa_var_info *use_info = &ssa->var_info[ssa_op->op1_use];
uint32_t use_type = use_info->type & (MAY_BE_ANY|MAY_BE_UNDEF);
if (use_type & MAY_BE_REF) {
return 0;
}
if (use_type & MAY_BE_UNDEF) {
use_type &= ~MAY_BE_UNDEF;
use_type |= MAY_BE_NULL;
}
uint32_t disallowed_types = use_type & ~ZEND_TYPE_PURE_MASK(arg_info->type);
if (!disallowed_types) {
/* Only contains allowed types. */
return true;
}
if (disallowed_types == MAY_BE_OBJECT && use_info->ce && ZEND_TYPE_IS_COMPLEX(arg_info->type)) {
return can_elide_list_type(script, op_array, use_info, arg_info->type);
}
return false;
}
static bool opline_supports_assign_contraction(
zend_op_array *op_array, zend_ssa *ssa, zend_op *opline, int src_var, uint32_t cv_var) {
if (opline->opcode == ZEND_NEW) {
/* see Zend/tests/generators/aborted_yield_during_new.phpt */
return 0;
}
if (opline->opcode == ZEND_DO_ICALL || opline->opcode == ZEND_DO_UCALL
|| opline->opcode == ZEND_DO_FCALL || opline->opcode == ZEND_DO_FCALL_BY_NAME) {
/* Function calls may dtor the return value after it has already been written -- allow
* direct assignment only for types where a double-dtor does not matter. */
uint32_t type = ssa->var_info[src_var].type;
uint32_t simple = MAY_BE_NULL|MAY_BE_FALSE|MAY_BE_TRUE|MAY_BE_LONG|MAY_BE_DOUBLE;
return !((type & MAY_BE_ANY) & ~simple);
}
if (opline->opcode == ZEND_POST_INC || opline->opcode == ZEND_POST_DEC) {
/* POST_INC/DEC write the result variable before performing the inc/dec. For $i = $i++
* eliding the temporary variable would thus yield an incorrect result. */
return opline->op1_type != IS_CV || opline->op1.var != cv_var;
}
if (opline->opcode == ZEND_INIT_ARRAY) {
/* INIT_ARRAY initializes the result array before reading key/value. */
return (opline->op1_type != IS_CV || opline->op1.var != cv_var)
&& (opline->op2_type != IS_CV || opline->op2.var != cv_var);
}
if (opline->opcode == ZEND_CAST
&& (opline->extended_value == IS_ARRAY || opline->extended_value == IS_OBJECT)) {
/* CAST to array/object may initialize the result to an empty array/object before
* reading the expression. */
return opline->op1_type != IS_CV || opline->op1.var != cv_var;
}
if ((opline->opcode == ZEND_ASSIGN_OP
|| opline->opcode == ZEND_ASSIGN_OBJ
|| opline->opcode == ZEND_ASSIGN_DIM
|| opline->opcode == ZEND_ASSIGN_OBJ_OP
|| opline->opcode == ZEND_ASSIGN_DIM_OP)
&& opline->op1_type == IS_CV
&& opline->op1.var == cv_var
&& zend_may_throw(opline, &ssa->ops[ssa->vars[src_var].definition], op_array, ssa)) {
return 0;
}
return 1;
}
static bool variable_defined_or_used_in_range(zend_ssa *ssa, int var, int start, int end)
{
while (start < end) {
const zend_ssa_op *ssa_op = &ssa->ops[start];
if ((ssa_op->op1_def >= 0 && ssa->vars[ssa_op->op1_def].var == var) ||
(ssa_op->op2_def >= 0 && ssa->vars[ssa_op->op2_def].var == var) ||
(ssa_op->result_def >= 0 && ssa->vars[ssa_op->result_def].var == var) ||
(ssa_op->op1_use >= 0 && ssa->vars[ssa_op->op1_use].var == var) ||
(ssa_op->op2_use >= 0 && ssa->vars[ssa_op->op2_use].var == var) ||
(ssa_op->result_use >= 0 && ssa->vars[ssa_op->result_use].var == var)
) {
return 1;
}
start++;
}
return 0;
}
int zend_dfa_optimize_calls(zend_op_array *op_array, zend_ssa *ssa)
{
zend_func_info *func_info = ZEND_FUNC_INFO(op_array);
int removed_ops = 0;
if (func_info->callee_info) {
zend_call_info *call_info = func_info->callee_info;
do {
if (call_info->caller_call_opline
&& call_info->caller_call_opline->opcode == ZEND_DO_ICALL
&& call_info->callee_func
&& zend_string_equals_literal(call_info->callee_func->common.function_name, "in_array")
&& (call_info->caller_init_opline->extended_value == 2
|| (call_info->caller_init_opline->extended_value == 3
&& (call_info->caller_call_opline - 1)->opcode == ZEND_SEND_VAL
&& (call_info->caller_call_opline - 1)->op1_type == IS_CONST))) {
zend_op *send_array;
zend_op *send_needly;
bool strict = 0;
ZEND_ASSERT(!call_info->is_prototype);
if (call_info->caller_init_opline->extended_value == 2) {
send_array = call_info->caller_call_opline - 1;
send_needly = call_info->caller_call_opline - 2;
} else {
if (zend_is_true(CT_CONSTANT_EX(op_array, (call_info->caller_call_opline - 1)->op1.constant))) {
strict = 1;
}
send_array = call_info->caller_call_opline - 2;
send_needly = call_info->caller_call_opline - 3;
}
if (send_array->opcode == ZEND_SEND_VAL
&& send_array->op1_type == IS_CONST
&& Z_TYPE_P(CT_CONSTANT_EX(op_array, send_array->op1.constant)) == IS_ARRAY
&& (send_needly->opcode == ZEND_SEND_VAL
|| send_needly->opcode == ZEND_SEND_VAR)
) {
bool ok = 1;
HashTable *src = Z_ARRVAL_P(CT_CONSTANT_EX(op_array, send_array->op1.constant));
HashTable *dst;
zval *val, tmp;
zend_ulong idx;
ZVAL_TRUE(&tmp);
dst = zend_new_array(zend_hash_num_elements(src));
if (strict) {
ZEND_HASH_FOREACH_VAL(src, val) {
if (Z_TYPE_P(val) == IS_STRING) {
zend_hash_add(dst, Z_STR_P(val), &tmp);
} else if (Z_TYPE_P(val) == IS_LONG) {
zend_hash_index_add(dst, Z_LVAL_P(val), &tmp);
} else {
zend_array_destroy(dst);
ok = 0;
break;
}
} ZEND_HASH_FOREACH_END();
} else {
ZEND_HASH_FOREACH_VAL(src, val) {
if (Z_TYPE_P(val) != IS_STRING || ZEND_HANDLE_NUMERIC(Z_STR_P(val), idx)) {
zend_array_destroy(dst);
ok = 0;
break;
}
zend_hash_add(dst, Z_STR_P(val), &tmp);
} ZEND_HASH_FOREACH_END();
}
if (ok) {
uint32_t op_num = send_needly - op_array->opcodes;
zend_ssa_op *ssa_op = ssa->ops + op_num;
if (ssa_op->op1_use >= 0) {
/* Reconstruct SSA */
int var_num = ssa_op->op1_use;
zend_ssa_var *var = ssa->vars + var_num;
ZEND_ASSERT(ssa_op->op1_def < 0);
zend_ssa_unlink_use_chain(ssa, op_num, ssa_op->op1_use);
ssa_op->op1_use = -1;
ssa_op->op1_use_chain = -1;
op_num = call_info->caller_call_opline - op_array->opcodes;
ssa_op = ssa->ops + op_num;
ssa_op->op1_use = var_num;
ssa_op->op1_use_chain = var->use_chain;
var->use_chain = op_num;
}
ZVAL_ARR(&tmp, dst);
/* Update opcode */
call_info->caller_call_opline->opcode = ZEND_IN_ARRAY;
call_info->caller_call_opline->extended_value = strict;
call_info->caller_call_opline->op1_type = send_needly->op1_type;
call_info->caller_call_opline->op1.num = send_needly->op1.num;
call_info->caller_call_opline->op2_type = IS_CONST;
call_info->caller_call_opline->op2.constant = zend_optimizer_add_literal(op_array, &tmp);
if (call_info->caller_init_opline->extended_value == 3) {
MAKE_NOP(call_info->caller_call_opline - 1);
}
MAKE_NOP(call_info->caller_init_opline);
MAKE_NOP(send_needly);
MAKE_NOP(send_array);
removed_ops++;
op_num = call_info->caller_call_opline - op_array->opcodes;
ssa_op = ssa->ops + op_num;
if (ssa_op->result_def >= 0) {
int var = ssa_op->result_def;
int use = ssa->vars[var].use_chain;
/* If the result is used only in a JMPZ/JMPNZ, replace result type with
* IS_TMP_VAR, which will enable use of smart branches. Don't do this
* in other cases, as not all opcodes support both VAR and TMP. */
if (ssa->vars[var].phi_use_chain == NULL
&& ssa->ops[use].op1_use == var
&& ssa->ops[use].op1_use_chain == -1
&& (op_array->opcodes[use].opcode == ZEND_JMPZ
|| op_array->opcodes[use].opcode == ZEND_JMPNZ)) {
call_info->caller_call_opline->result_type = IS_TMP_VAR;
op_array->opcodes[use].op1_type = IS_TMP_VAR;
}
}
}
}
}
call_info = call_info->next_callee;
} while (call_info);
}
return removed_ops;
}
static zend_always_inline void take_successor_0(zend_ssa *ssa, int block_num, zend_basic_block *block)
{
if (block->successors_count == 2) {
if (block->successors[1] != block->successors[0]) {
zend_ssa_remove_predecessor(ssa, block_num, block->successors[1]);
}
block->successors_count = 1;
}
}
static zend_always_inline void take_successor_1(zend_ssa *ssa, int block_num, zend_basic_block *block)
{
if (block->successors_count == 2) {
if (block->successors[1] != block->successors[0]) {
zend_ssa_remove_predecessor(ssa, block_num, block->successors[0]);
block->successors[0] = block->successors[1];
}
block->successors_count = 1;
}
}
static zend_always_inline void take_successor_ex(zend_ssa *ssa, int block_num, zend_basic_block *block, int target_block)
{
int i;
for (i = 0; i < block->successors_count; i++) {
if (block->successors[i] != target_block) {
zend_ssa_remove_predecessor(ssa, block_num, block->successors[i]);
}
}
block->successors[0] = target_block;
block->successors_count = 1;
}
static void compress_block(zend_op_array *op_array, zend_basic_block *block)
{
while (block->len > 0) {
zend_op *opline = &op_array->opcodes[block->start + block->len - 1];
if (opline->opcode == ZEND_NOP) {
block->len--;
} else {
break;
}
}
}
static void replace_predecessor(zend_ssa *ssa, int block_id, int old_pred, int new_pred) {
zend_basic_block *block = &ssa->cfg.blocks[block_id];
int *predecessors = &ssa->cfg.predecessors[block->predecessor_offset];
zend_ssa_phi *phi;
int i;
int old_pred_idx = -1;
int new_pred_idx = -1;
for (i = 0; i < block->predecessors_count; i++) {
if (predecessors[i] == old_pred) {
old_pred_idx = i;
}
if (predecessors[i] == new_pred) {
new_pred_idx = i;
}
}
ZEND_ASSERT(old_pred_idx != -1);
if (new_pred_idx == -1) {
/* If the new predecessor doesn't exist yet, simply rewire the old one */
predecessors[old_pred_idx] = new_pred;
} else {
/* Otherwise, rewiring the old predecessor would make the new predecessor appear
* twice, which violates our CFG invariants. Remove the old predecessor instead. */
memmove(
predecessors + old_pred_idx,
predecessors + old_pred_idx + 1,
sizeof(int) * (block->predecessors_count - old_pred_idx - 1)
);
/* Also remove the corresponding phi node entries */
for (phi = ssa->blocks[block_id].phis; phi; phi = phi->next) {
if (phi->pi >= 0) {
if (phi->pi == old_pred || phi->pi == new_pred) {
zend_ssa_rename_var_uses(
ssa, phi->ssa_var, phi->sources[0], /* update_types */ 0);
zend_ssa_remove_phi(ssa, phi);
}
} else {
memmove(
phi->sources + old_pred_idx,
phi->sources + old_pred_idx + 1,
sizeof(int) * (block->predecessors_count - old_pred_idx - 1)
);
}
}
block->predecessors_count--;
}
}
static void zend_ssa_replace_control_link(zend_op_array *op_array, zend_ssa *ssa, int from, int to, int new_to)
{
zend_basic_block *src = &ssa->cfg.blocks[from];
zend_basic_block *old = &ssa->cfg.blocks[to];
zend_basic_block *dst = &ssa->cfg.blocks[new_to];
int i;
zend_op *opline;
for (i = 0; i < src->successors_count; i++) {
if (src->successors[i] == to) {
src->successors[i] = new_to;
}
}
if (src->len > 0) {
opline = op_array->opcodes + src->start + src->len - 1;
switch (opline->opcode) {
case ZEND_JMP:
case ZEND_FAST_CALL:
ZEND_ASSERT(ZEND_OP1_JMP_ADDR(opline) == op_array->opcodes + old->start);
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, op_array->opcodes + dst->start);
break;
case ZEND_JMPZ:
case ZEND_JMPNZ:
case ZEND_JMPZ_EX:
case ZEND_JMPNZ_EX:
case ZEND_FE_RESET_R:
case ZEND_FE_RESET_RW:
case ZEND_JMP_SET:
case ZEND_COALESCE:
case ZEND_ASSERT_CHECK:
case ZEND_JMP_NULL:
case ZEND_BIND_INIT_STATIC_OR_JMP:
if (ZEND_OP2_JMP_ADDR(opline) == op_array->opcodes + old->start) {
ZEND_SET_OP_JMP_ADDR(opline, opline->op2, op_array->opcodes + dst->start);
}
break;
case ZEND_CATCH:
if (!(opline->extended_value & ZEND_LAST_CATCH)) {
if (ZEND_OP2_JMP_ADDR(opline) == op_array->opcodes + old->start) {
ZEND_SET_OP_JMP_ADDR(opline, opline->op2, op_array->opcodes + dst->start);
}
}
break;
case ZEND_FE_FETCH_R:
case ZEND_FE_FETCH_RW:
if (ZEND_OFFSET_TO_OPLINE_NUM(op_array, opline, opline->extended_value) == old->start) {
opline->extended_value = ZEND_OPLINE_NUM_TO_OFFSET(op_array, opline, dst->start);
}
break;
case ZEND_SWITCH_LONG:
case ZEND_SWITCH_STRING:
case ZEND_MATCH:
{
HashTable *jumptable = Z_ARRVAL(ZEND_OP2_LITERAL(opline));
zval *zv;
ZEND_HASH_FOREACH_VAL(jumptable, zv) {
if (ZEND_OFFSET_TO_OPLINE_NUM(op_array, opline, Z_LVAL_P(zv)) == old->start) {
Z_LVAL_P(zv) = ZEND_OPLINE_NUM_TO_OFFSET(op_array, opline, dst->start);
}
} ZEND_HASH_FOREACH_END();
if (ZEND_OFFSET_TO_OPLINE_NUM(op_array, opline, opline->extended_value) == old->start) {
opline->extended_value = ZEND_OPLINE_NUM_TO_OFFSET(op_array, opline, dst->start);
}
break;
}
}
}
replace_predecessor(ssa, new_to, to, from);
}
static void zend_ssa_unlink_block(zend_op_array *op_array, zend_ssa *ssa, zend_basic_block *block, int block_num)
{
if (block->predecessors_count == 1 && ssa->blocks[block_num].phis == NULL) {
int *predecessors, i;
zend_basic_block *fe_fetch_block = NULL;
ZEND_ASSERT(block->successors_count == 1);
predecessors = &ssa->cfg.predecessors[block->predecessor_offset];
if (block->predecessors_count == 1 && (block->flags & ZEND_BB_FOLLOW)) {
zend_basic_block *pred_block = &ssa->cfg.blocks[predecessors[0]];
if (pred_block->len > 0 && (pred_block->flags & ZEND_BB_REACHABLE)) {
if ((op_array->opcodes[pred_block->start + pred_block->len - 1].opcode == ZEND_FE_FETCH_R
|| op_array->opcodes[pred_block->start + pred_block->len - 1].opcode == ZEND_FE_FETCH_RW)
&& op_array->opcodes[pred_block->start + pred_block->len - 1].op2_type == IS_CV) {
fe_fetch_block = pred_block;
}
}
}
for (i = 0; i < block->predecessors_count; i++) {
zend_ssa_replace_control_link(op_array, ssa, predecessors[i], block_num, block->successors[0]);
}
zend_ssa_remove_block(op_array, ssa, block_num);
if (fe_fetch_block && fe_fetch_block->successors[0] == fe_fetch_block->successors[1]) {
/* The body of "foreach" loop was removed */
int ssa_var = ssa->ops[fe_fetch_block->start + fe_fetch_block->len - 1].op2_def;
if (ssa_var >= 0) {
zend_ssa_remove_uses_of_var(ssa, ssa_var);
}
}
}
}
static int zend_dfa_optimize_jmps(zend_op_array *op_array, zend_ssa *ssa)
{
int removed_ops = 0;
int block_num = 0;
for (block_num = 1; block_num < ssa->cfg.blocks_count; block_num++) {
zend_basic_block *block = &ssa->cfg.blocks[block_num];
if (!(block->flags & ZEND_BB_REACHABLE)) {
continue;
}
compress_block(op_array, block);
if (block->len == 0) {
zend_ssa_unlink_block(op_array, ssa, block, block_num);
}
}
block_num = 0;
while (block_num < ssa->cfg.blocks_count
&& !(ssa->cfg.blocks[block_num].flags & ZEND_BB_REACHABLE)) {
block_num++;
}
while (block_num < ssa->cfg.blocks_count) {
int next_block_num = block_num + 1;
zend_basic_block *block = &ssa->cfg.blocks[block_num];
uint32_t op_num;
zend_op *opline;
zend_ssa_op *ssa_op;
bool can_follow = 1;
while (next_block_num < ssa->cfg.blocks_count
&& !(ssa->cfg.blocks[next_block_num].flags & ZEND_BB_REACHABLE)) {
if (ssa->cfg.blocks[next_block_num].flags & ZEND_BB_UNREACHABLE_FREE) {
can_follow = 0;
}
next_block_num++;
}
if (block->len) {
op_num = block->start + block->len - 1;
opline = op_array->opcodes + op_num;
ssa_op = ssa->ops + op_num;
switch (opline->opcode) {
case ZEND_JMP:
optimize_jmp:
if (block->successors[0] == next_block_num && can_follow) {
MAKE_NOP(opline);
removed_ops++;
goto optimize_nop;
}
break;
case ZEND_JMPZ:
optimize_jmpz:
if (opline->op1_type == IS_CONST) {
if (zend_is_true(CT_CONSTANT_EX(op_array, opline->op1.constant))) {
MAKE_NOP(opline);
removed_ops++;
take_successor_1(ssa, block_num, block);
goto optimize_nop;
} else {
opline->opcode = ZEND_JMP;
COPY_NODE(opline->op1, opline->op2);
take_successor_0(ssa, block_num, block);
goto optimize_jmp;
}
} else {
if (block->successors[0] == next_block_num && can_follow) {
take_successor_0(ssa, block_num, block);
if (opline->op1_type == IS_CV && (OP1_INFO() & MAY_BE_UNDEF)) {
opline->opcode = ZEND_CHECK_VAR;
opline->op2.num = 0;
} else if (opline->op1_type == IS_CV || !(OP1_INFO() & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))) {
zend_ssa_remove_instr(ssa, opline, ssa_op);
removed_ops++;
goto optimize_nop;
} else {
opline->opcode = ZEND_FREE;
opline->op2.num = 0;
}
}
}
break;
case ZEND_JMPNZ:
optimize_jmpnz:
if (opline->op1_type == IS_CONST) {
if (zend_is_true(CT_CONSTANT_EX(op_array, opline->op1.constant))) {
opline->opcode = ZEND_JMP;
COPY_NODE(opline->op1, opline->op2);
take_successor_0(ssa, block_num, block);
goto optimize_jmp;
} else {
MAKE_NOP(opline);
removed_ops++;
take_successor_1(ssa, block_num, block);
goto optimize_nop;
}
} else if (block->successors_count == 2) {
if (block->successors[0] == next_block_num && can_follow) {
take_successor_0(ssa, block_num, block);
if (opline->op1_type == IS_CV && (OP1_INFO() & MAY_BE_UNDEF)) {
opline->opcode = ZEND_CHECK_VAR;
opline->op2.num = 0;
} else if (opline->op1_type == IS_CV || !(OP1_INFO() & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))) {
zend_ssa_remove_instr(ssa, opline, ssa_op);
removed_ops++;
goto optimize_nop;
} else {
opline->opcode = ZEND_FREE;
opline->op2.num = 0;
}
}
}
break;
case ZEND_JMPZ_EX:
if (ssa->vars[ssa_op->result_def].use_chain < 0
&& ssa->vars[ssa_op->result_def].phi_use_chain == NULL) {
opline->opcode = ZEND_JMPZ;
opline->result_type = IS_UNUSED;
zend_ssa_remove_result_def(ssa, ssa_op);
goto optimize_jmpz;
} else if (opline->op1_type == IS_CONST) {
if (zend_is_true(CT_CONSTANT_EX(op_array, opline->op1.constant))) {
opline->opcode = ZEND_BOOL;
take_successor_1(ssa, block_num, block);
}
}
break;
case ZEND_JMPNZ_EX:
if (ssa->vars[ssa_op->result_def].use_chain < 0
&& ssa->vars[ssa_op->result_def].phi_use_chain == NULL) {
opline->opcode = ZEND_JMPNZ;
opline->result_type = IS_UNUSED;
zend_ssa_remove_result_def(ssa, ssa_op);
goto optimize_jmpnz;
} else if (opline->op1_type == IS_CONST) {
if (!zend_is_true(CT_CONSTANT_EX(op_array, opline->op1.constant))) {
opline->opcode = ZEND_BOOL;
take_successor_1(ssa, block_num, block);
}
}
break;
case ZEND_JMP_SET:
if (ssa->vars[ssa_op->result_def].use_chain < 0
&& ssa->vars[ssa_op->result_def].phi_use_chain == NULL) {
opline->opcode = ZEND_JMPNZ;
opline->result_type = IS_UNUSED;
zend_ssa_remove_result_def(ssa, ssa_op);
goto optimize_jmpnz;
} else if (opline->op1_type == IS_CONST) {
if (!zend_is_true(CT_CONSTANT_EX(op_array, opline->op1.constant))) {
MAKE_NOP(opline);
removed_ops++;
take_successor_1(ssa, block_num, block);
zend_ssa_remove_result_def(ssa, ssa_op);
goto optimize_nop;
}
}
break;
case ZEND_COALESCE:
{
zend_ssa_var *var = &ssa->vars[ssa_op->result_def];
if (opline->op1_type == IS_CONST
&& var->use_chain < 0 && var->phi_use_chain == NULL) {
if (Z_TYPE_P(CT_CONSTANT_EX(op_array, opline->op1.constant)) == IS_NULL) {
zend_ssa_remove_result_def(ssa, ssa_op);
MAKE_NOP(opline);
removed_ops++;
take_successor_1(ssa, block_num, block);
goto optimize_nop;
} else {
opline->opcode = ZEND_JMP;
opline->result_type = IS_UNUSED;
zend_ssa_remove_result_def(ssa, ssa_op);
COPY_NODE(opline->op1, opline->op2);
take_successor_0(ssa, block_num, block);
goto optimize_jmp;
}
}
break;
}
case ZEND_JMP_NULL:
{
zend_ssa_var *var = &ssa->vars[ssa_op->result_def];
if (opline->op1_type == IS_CONST
&& var->use_chain < 0 && var->phi_use_chain == NULL) {
if (Z_TYPE_P(CT_CONSTANT_EX(op_array, opline->op1.constant)) == IS_NULL) {
opline->opcode = ZEND_JMP;
opline->result_type = IS_UNUSED;
zend_ssa_remove_result_def(ssa, ssa_op);
COPY_NODE(opline->op1, opline->op2);
take_successor_0(ssa, block_num, block);
goto optimize_jmp;
} else {
zend_ssa_remove_result_def(ssa, ssa_op);
MAKE_NOP(opline);
removed_ops++;
take_successor_1(ssa, block_num, block);
goto optimize_nop;
}
}
break;
}
case ZEND_SWITCH_LONG:
case ZEND_SWITCH_STRING:
case ZEND_MATCH:
if (opline->op1_type == IS_CONST) {
zval *zv = CT_CONSTANT_EX(op_array, opline->op1.constant);
uint8_t type = Z_TYPE_P(zv);
bool correct_type =
(opline->opcode == ZEND_SWITCH_LONG && type == IS_LONG)
|| (opline->opcode == ZEND_SWITCH_STRING && type == IS_STRING)
|| (opline->opcode == ZEND_MATCH && (type == IS_LONG || type == IS_STRING));
/* Switch statements have a fallback chain for loose comparison. In those
* cases the SWITCH_* instruction is a NOP. Match does strict comparison and
* thus jumps to the default branch on mismatched types, so we need to
* convert MATCH to a jmp. */
if (!correct_type && opline->opcode != ZEND_MATCH) {
removed_ops++;
MAKE_NOP(opline);
opline->extended_value = 0;
take_successor_ex(ssa, block_num, block, block->successors[block->successors_count - 1]);
goto optimize_nop;
}
uint32_t target;
if (correct_type) {
HashTable *jmptable = Z_ARRVAL_P(CT_CONSTANT_EX(op_array, opline->op2.constant));
zval *jmp_zv = type == IS_LONG
? zend_hash_index_find(jmptable, Z_LVAL_P(zv))
: zend_hash_find(jmptable, Z_STR_P(zv));
if (jmp_zv) {
target = ZEND_OFFSET_TO_OPLINE_NUM(op_array, opline, Z_LVAL_P(jmp_zv));
} else {
target = ZEND_OFFSET_TO_OPLINE_NUM(op_array, opline, opline->extended_value);
}
} else {
ZEND_ASSERT(opline->opcode == ZEND_MATCH);
target = ZEND_OFFSET_TO_OPLINE_NUM(op_array, opline, opline->extended_value);
}
opline->opcode = ZEND_JMP;
opline->extended_value = 0;
SET_UNUSED(opline->op1);
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, op_array->opcodes + target);
SET_UNUSED(opline->op2);
take_successor_ex(ssa, block_num, block, ssa->cfg.map[target]);
goto optimize_jmp;
}
break;
case ZEND_NOP:
optimize_nop:
compress_block(op_array, block);
if (block->len == 0) {
if (block_num > 0) {
zend_ssa_unlink_block(op_array, ssa, block, block_num);
/* backtrack to previous basic block */
do {
block_num--;
} while (block_num >= 0
&& !(ssa->cfg.blocks[block_num].flags & ZEND_BB_REACHABLE));
if (block_num >= 0) {
continue;
}
}
}
break;
default:
break;
}
}