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php-src/ext/opcache/Optimizer/dfa_pass.c
Nikita Popov 6aece7be0a Optimize VERIFY_RETURN_TYPE for TMP operands as well 
Only exclude CONST operands, which use a different instruction
format (they have a return operand).
2019-10-25 11:37:19 +02:00

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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: |
| http://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 "php.h"
#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
int 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));
if (zend_build_cfg(&ctx->arena, op_array, ZEND_CFG_NO_ENTRY_PREDECESSORS, &ssa->cfg) != SUCCESS) {
return FAILURE;
}
if ((ssa->cfg.flags & ZEND_FUNC_INDIRECT_VAR_ACCESS)) {
/* TODO: we can't analyze functions with indirect variable access ??? */
return FAILURE;
}
if (zend_cfg_build_predecessors(&ctx->arena, &ssa->cfg) != SUCCESS) {
return FAILURE;
}
if (ctx->debug_level & ZEND_DUMP_DFA_CFG) {
zend_dump_op_array(op_array, ZEND_DUMP_CFG, "dfa cfg", &ssa->cfg);
}
/* Compute Dominators Tree */
if (zend_cfg_compute_dominators_tree(op_array, &ssa->cfg) != SUCCESS) {
return FAILURE;
}
/* Identify reducible and irreducible loops */
if (zend_cfg_identify_loops(op_array, &ssa->cfg) != SUCCESS) {
return FAILURE;
}
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) != SUCCESS) {
return FAILURE;
}
if (ctx->debug_level & ZEND_DUMP_DFA_SSA) {
zend_dump_op_array(op_array, ZEND_DUMP_SSA, "dfa ssa", ssa);
}
if (zend_ssa_compute_use_def_chains(&ctx->arena, op_array, ssa) != SUCCESS){
return FAILURE;
}
if (zend_ssa_find_false_dependencies(op_array, ssa) != SUCCESS) {
return FAILURE;
}
if (zend_ssa_find_sccs(op_array, ssa) != SUCCESS){
return FAILURE;
}
if (zend_ssa_inference(&ctx->arena, op_array, ctx->script, ssa, ctx->optimization_level) != SUCCESS) {
return FAILURE;
}
if (zend_ssa_escape_analysis(ctx->script, op_array, ssa) != SUCCESS) {
return FAILURE;
}
if (ctx->debug_level & ZEND_DUMP_DFA_SSA_VARS) {
zend_dump_ssa_variables(op_array, ssa, 0);
}
return SUCCESS;
}
static zend_bool is_smart_branch_inhibiting_nop(
zend_op_array *op_array, uint32_t target, uint32_t current,
zend_basic_block *b, zend_basic_block *blocks_end)
{
uint32_t next;
/* Target points one past the last non-nop instruction. Make sure there is one. */
if (target == 0) {
return 0;
}
/* Find the next instruction, skipping unreachable or empty blocks. */
next = current + 1;
if (next >= b->start + b->len) {
do {
b++;
if (b == blocks_end) {
return 0;
}
} while (!(b->flags & ZEND_BB_REACHABLE) || b->len == 0);
next = b->start;
}
return (op_array->opcodes[next].opcode == ZEND_JMPZ ||
op_array->opcodes[next].opcode == ZEND_JMPNZ) &&
zend_is_smart_branch(op_array->opcodes + target - 1);
}
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) ||
is_smart_branch_inhibiting_nop(op_array, target, i, b, blocks_end)) {
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 early binding list */
if (op_array->fn_flags & ZEND_ACC_EARLY_BINDING) {
uint32_t *opline_num = &ctx->script->first_early_binding_opline;
ZEND_ASSERT(op_array == &ctx->script->main_op_array);
do {
*opline_num -= shiftlist[*opline_num];
opline_num = &op_array->opcodes[*opline_num].result.opline_num;
} while (*opline_num != (uint32_t)-1);
}
/* 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];
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 zend_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 zend_bool can_elide_return_type_check(
zend_op_array *op_array, zend_ssa *ssa, zend_ssa_op *ssa_op) {
zend_arg_info *info = &op_array->arg_info[-1];
zend_ssa_var_info *use_info = &ssa->var_info[ssa_op->op1_use];
zend_ssa_var_info *def_info = &ssa->var_info[ssa_op->op1_def];
if (use_info->type & MAY_BE_REF) {
return 0;
}
/* A type is possible that is not in the allowed types */
if ((use_info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) & ~(def_info->type & MAY_BE_ANY)) {
return 0;
}
/* These types are not represented exactly */
if (ZEND_TYPE_CODE(info->type) == IS_CALLABLE || ZEND_TYPE_CODE(info->type) == IS_ITERABLE) {
return 0;
}
if (ZEND_TYPE_IS_CLASS(info->type)) {
if (!use_info->ce || !def_info->ce || !safe_instanceof(use_info->ce, def_info->ce)) {
return 0;
}
}
return 1;
}
static zend_bool opline_supports_assign_contraction(
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;
}
return 1;
}
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->opcode == ZEND_DO_ICALL
&& call_info->callee_func
&& ZSTR_LEN(call_info->callee_func->common.function_name) == sizeof("in_array")-1
&& memcmp(ZSTR_VAL(call_info->callee_func->common.function_name), "in_array", sizeof("in_array")-1) == 0
&& (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;
zend_bool strict = 0;
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)
) {
int 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++;
}
}
}
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 == 1 || !zend_is_smart_branch(opline - 1))) {
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) {
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_JMPZNZ:
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 missing intentionally */
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:
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:
{
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_ASSERT(block->successors_count == 1);
predecessors = &ssa->cfg.predecessors[block->predecessor_offset];
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);
}
}
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;
while (next_block_num < ssa->cfg.blocks_count
&& !(ssa->cfg.blocks[next_block_num].flags & ZEND_BB_REACHABLE)) {
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) {
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) {
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) {
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_JMPZNZ:
if (opline->op1_type == IS_CONST) {
if (zend_is_true(CT_CONSTANT_EX(op_array, opline->op1.constant))) {
zend_op *target_opline = ZEND_OFFSET_TO_OPLINE(opline, opline->extended_value);
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target_opline);
take_successor_1(ssa, block_num, block);
} else {
zend_op *target_opline = ZEND_OP2_JMP_ADDR(opline);
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target_opline);
take_successor_0(ssa, block_num, block);
}
opline->op1_type = IS_UNUSED;
opline->extended_value = 0;
opline->opcode = ZEND_JMP;
goto optimize_jmp;
} else if (block->successors_count == 2) {
if (block->successors[0] == block->successors[1]) {
take_successor_0(ssa, block_num, block);
if (block->successors[0] == next_block_num) {
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;
}
} else if ((opline->op1_type == IS_CV && !(OP1_INFO() & MAY_BE_UNDEF)) || !(OP1_INFO() & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))) {
ZEND_ASSERT(ssa_op->op1_use >= 0);
zend_ssa_unlink_use_chain(ssa, op_num, ssa_op->op1_use);
ssa_op->op1_use = -1;
ssa_op->op1_use_chain = -1;
opline->opcode = ZEND_JMP;
opline->op1_type = IS_UNUSED;
opline->op1.num = opline->op2.num;
goto optimize_jmp;
}
}
}
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_QM_ASSIGN;
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_QM_ASSIGN;
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_SWITCH_LONG:
if (opline->op1_type == IS_CONST) {
zval *zv = CT_CONSTANT_EX(op_array, opline->op1.constant);
if (Z_TYPE_P(zv) != IS_LONG) {
removed_ops++;
MAKE_NOP(opline);
opline->extended_value = 0;
take_successor_ex(ssa, block_num, block, block->successors[0]);
goto optimize_nop;
} else {
HashTable *jmptable = Z_ARRVAL_P(CT_CONSTANT_EX(op_array, opline->op2.constant));
zval *jmp_zv = zend_hash_index_find(jmptable, Z_LVAL_P(zv));
uint32_t target;
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);
}
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_SWITCH_STRING:
if (opline->op1_type == IS_CONST) {
zval *zv = CT_CONSTANT_EX(op_array, opline->op1.constant);
if (Z_TYPE_P(zv) != IS_STRING) {
removed_ops++;
MAKE_NOP(opline);
opline->extended_value = 0;
take_successor_ex(ssa, block_num, block, block->successors[0]);
goto optimize_nop;
} else {
HashTable *jmptable = Z_ARRVAL_P(CT_CONSTANT_EX(op_array, opline->op2.constant));
zval *jmp_zv = zend_hash_find(jmptable, Z_STR_P(zv));
uint32_t target;
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);
}
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;
}
}
block_num = next_block_num;
}
return removed_ops;
}
void zend_dfa_optimize_op_array(zend_op_array *op_array, zend_optimizer_ctx *ctx, zend_ssa *ssa, zend_call_info **call_map)
{
if (ctx->debug_level & ZEND_DUMP_BEFORE_DFA_PASS) {
zend_dump_op_array(op_array, ZEND_DUMP_SSA, "before dfa pass", ssa);
}
if (ssa->var_info) {
int op_1;
int v;
int remove_nops = 0;
zend_op *opline;
zval tmp;
#if ZEND_DEBUG_DFA
ssa_verify_integrity(op_array, ssa, "before dfa");
#endif
if (ZEND_OPTIMIZER_PASS_8 & ctx->optimization_level) {
if (sccp_optimize_op_array(ctx, op_array, ssa, call_map)) {
remove_nops = 1;
}
if (zend_dfa_optimize_jmps(op_array, ssa)) {
remove_nops = 1;
}
#if ZEND_DEBUG_DFA
ssa_verify_integrity(op_array, ssa, "after sccp");
#endif
if (ZEND_FUNC_INFO(op_array)) {
if (zend_dfa_optimize_calls(op_array, ssa)) {
remove_nops = 1;
}
}
if (ctx->debug_level & ZEND_DUMP_AFTER_PASS_8) {
zend_dump_op_array(op_array, ZEND_DUMP_SSA, "after sccp pass", ssa);
}
#if ZEND_DEBUG_DFA
ssa_verify_integrity(op_array, ssa, "after calls");
#endif
}
if (ZEND_OPTIMIZER_PASS_14 & ctx->optimization_level) {
if (dce_optimize_op_array(op_array, ssa, 0)) {
remove_nops = 1;
}
if (zend_dfa_optimize_jmps(op_array, ssa)) {
remove_nops = 1;
}
if (ctx->debug_level & ZEND_DUMP_AFTER_PASS_14) {
zend_dump_op_array(op_array, ZEND_DUMP_SSA, "after dce pass", ssa);
}
#if ZEND_DEBUG_DFA
ssa_verify_integrity(op_array, ssa, "after dce");
#endif
}
for (v = op_array->last_var; v < ssa->vars_count; v++) {
op_1 = ssa->vars[v].definition;
if (op_1 < 0) {
continue;
}
opline = op_array->opcodes + op_1;
/* Convert LONG constants to DOUBLE */
if (ssa->var_info[v].use_as_double) {
if (opline->opcode == ZEND_ASSIGN
&& opline->op2_type == IS_CONST
&& ssa->ops[op_1].op1_def == v
&& !RETURN_VALUE_USED(opline)
) {
// op_1: ASSIGN ? -> #v [use_as_double], long(?) => ASSIGN ? -> #v, double(?)
zval *zv = CT_CONSTANT_EX(op_array, opline->op2.constant);
ZEND_ASSERT(Z_TYPE_INFO_P(zv) == IS_LONG);
ZVAL_DOUBLE(&tmp, zval_get_double(zv));
opline->op2.constant = zend_optimizer_add_literal(op_array, &tmp);
} else if (opline->opcode == ZEND_QM_ASSIGN
&& opline->op1_type == IS_CONST
) {
// op_1: QM_ASSIGN #v [use_as_double], long(?) => QM_ASSIGN #v, double(?)
zval *zv = CT_CONSTANT_EX(op_array, opline->op1.constant);
ZEND_ASSERT(Z_TYPE_INFO_P(zv) == IS_LONG);
ZVAL_DOUBLE(&tmp, zval_get_double(zv));
opline->op1.constant = zend_optimizer_add_literal(op_array, &tmp);
}
} else {
if (opline->opcode == ZEND_ADD
|| opline->opcode == ZEND_SUB
|| opline->opcode == ZEND_MUL
|| opline->opcode == ZEND_IS_EQUAL
|| opline->opcode == ZEND_IS_NOT_EQUAL
|| opline->opcode == ZEND_IS_SMALLER
|| opline->opcode == ZEND_IS_SMALLER_OR_EQUAL
) {
if (opline->op1_type == IS_CONST
&& opline->op2_type != IS_CONST
&& (OP2_INFO() & MAY_BE_ANY) == MAY_BE_DOUBLE
&& Z_TYPE_INFO_P(CT_CONSTANT_EX(op_array, opline->op1.constant)) == IS_LONG
) {
// op_1: #v.? = ADD long(?), #?.? [double] => #v.? = ADD double(?), #?.? [double]
zval *zv = CT_CONSTANT_EX(op_array, opline->op1.constant);
ZVAL_DOUBLE(&tmp, zval_get_double(zv));
opline->op1.constant = zend_optimizer_add_literal(op_array, &tmp);
} else if (opline->op1_type != IS_CONST
&& opline->op2_type == IS_CONST
&& (OP1_INFO() & MAY_BE_ANY) == MAY_BE_DOUBLE
&& Z_TYPE_INFO_P(CT_CONSTANT_EX(op_array, opline->op2.constant)) == IS_LONG
) {
// op_1: #v.? = ADD #?.? [double], long(?) => #v.? = ADD #?.? [double], double(?)
zval *zv = CT_CONSTANT_EX(op_array, opline->op2.constant);
ZVAL_DOUBLE(&tmp, zval_get_double(zv));
opline->op2.constant = zend_optimizer_add_literal(op_array, &tmp);
}
} else if (opline->opcode == ZEND_CONCAT) {
if (!(OP1_INFO() & MAY_BE_OBJECT)
&& !(OP2_INFO() & MAY_BE_OBJECT)) {
opline->opcode = ZEND_FAST_CONCAT;
}
} else if (opline->opcode == ZEND_VERIFY_RETURN_TYPE
&& opline->op1_type != IS_CONST
&& ssa->ops[op_1].op1_def == v
&& ssa->ops[op_1].op1_use >= 0
&& ssa->ops[op_1].op1_use_chain == -1
&& ssa->vars[v].use_chain >= 0
&& can_elide_return_type_check(op_array, ssa, &ssa->ops[op_1])) {
// op_1: VERIFY_RETURN_TYPE #orig_var.? [T] -> #v.? [T] => NOP
int orig_var = ssa->ops[op_1].op1_use;
if (zend_ssa_unlink_use_chain(ssa, op_1, orig_var)) {
int ret = ssa->vars[v].use_chain;
ssa->ops[ret].op1_use = orig_var;
ssa->ops[ret].op1_use_chain = ssa->vars[orig_var].use_chain;
ssa->vars[orig_var].use_chain = ret;
ssa->vars[v].definition = -1;
ssa->vars[v].use_chain = -1;
ssa->ops[op_1].op1_def = -1;
ssa->ops[op_1].op1_use = -1;
MAKE_NOP(opline);
remove_nops = 1;
}
}
}
if (ssa->vars[v].var >= op_array->last_var) {
/* skip TMP and VAR */
continue;
}
if (opline->opcode == ZEND_ASSIGN
&& ssa->ops[op_1].op1_def == v
&& !RETURN_VALUE_USED(opline)
) {
int orig_var = ssa->ops[op_1].op1_use;
if (orig_var >= 0
&& !(ssa->var_info[orig_var].type & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))
) {
int src_var = ssa->ops[op_1].op2_use;
if ((opline->op2_type & (IS_TMP_VAR|IS_VAR))
&& src_var >= 0
&& !(ssa->var_info[src_var].type & MAY_BE_REF)
&& ssa->vars[src_var].definition >= 0
&& ssa->ops[ssa->vars[src_var].definition].result_def == src_var
&& ssa->ops[ssa->vars[src_var].definition].result_use < 0
&& ssa->vars[src_var].use_chain == op_1
&& ssa->ops[op_1].op2_use_chain < 0
&& !ssa->vars[src_var].phi_use_chain
&& !ssa->vars[src_var].sym_use_chain
&& opline_supports_assign_contraction(
ssa, &op_array->opcodes[ssa->vars[src_var].definition],
src_var, opline->op1.var)
) {
int op_2 = ssa->vars[src_var].definition;
// op_2: #src_var.T = OP ... => #v.CV = OP ...
// op_1: ASSIGN #orig_var.CV [undef,scalar] -> #v.CV, #src_var.T NOP
if (zend_ssa_unlink_use_chain(ssa, op_1, orig_var)) {
/* Reconstruct SSA */
ssa->vars[v].definition = op_2;
ssa->ops[op_2].result_def = v;
ssa->vars[src_var].definition = -1;
ssa->vars[src_var].use_chain = -1;
ssa->ops[op_1].op1_use = -1;
ssa->ops[op_1].op2_use = -1;
ssa->ops[op_1].op1_def = -1;
ssa->ops[op_1].op1_use_chain = -1;
/* Update opcodes */
op_array->opcodes[op_2].result_type = opline->op1_type;
op_array->opcodes[op_2].result.var = opline->op1.var;
MAKE_NOP(opline);
remove_nops = 1;
}
} else if (opline->op2_type == IS_CONST
|| ((opline->op2_type & (IS_TMP_VAR|IS_VAR|IS_CV))
&& ssa->ops[op_1].op2_use >= 0
&& ssa->ops[op_1].op2_def < 0)
) {
// op_1: ASSIGN #orig_var.CV [undef,scalar] -> #v.CV, CONST|TMPVAR => QM_ASSIGN v.CV, CONST|TMPVAR
if (ssa->ops[op_1].op1_use != ssa->ops[op_1].op2_use) {
zend_ssa_unlink_use_chain(ssa, op_1, orig_var);
} else {
ssa->ops[op_1].op2_use_chain = ssa->ops[op_1].op1_use_chain;
}
/* Reconstruct SSA */
ssa->ops[op_1].result_def = v;
ssa->ops[op_1].op1_def = -1;
ssa->ops[op_1].op1_use = ssa->ops[op_1].op2_use;
ssa->ops[op_1].op1_use_chain = ssa->ops[op_1].op2_use_chain;
ssa->ops[op_1].op2_use = -1;
ssa->ops[op_1].op2_use_chain = -1;
/* Update opcode */
opline->result_type = opline->op1_type;
opline->result.var = opline->op1.var;
opline->op1_type = opline->op2_type;
opline->op1.var = opline->op2.var;
opline->op2_type = IS_UNUSED;
opline->op2.var = 0;
opline->opcode = ZEND_QM_ASSIGN;
}
}
} else if (opline->opcode == ZEND_ASSIGN_OP
&& opline->extended_value == ZEND_ADD
&& ssa->ops[op_1].op1_def == v
&& opline->op2_type == IS_CONST
&& Z_TYPE_P(CT_CONSTANT_EX(op_array, opline->op2.constant)) == IS_LONG
&& Z_LVAL_P(CT_CONSTANT_EX(op_array, opline->op2.constant)) == 1
&& ssa->ops[op_1].op1_use >= 0
&& !(ssa->var_info[ssa->ops[op_1].op1_use].type & (MAY_BE_FALSE|MAY_BE_TRUE|MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))) {
// op_1: ASSIGN_ADD #?.CV [undef,null,int,foat] ->#v.CV, int(1) => PRE_INC #?.CV ->#v.CV
opline->opcode = ZEND_PRE_INC;
opline->extended_value = 0;
SET_UNUSED(opline->op2);
} else if (opline->opcode == ZEND_ASSIGN_OP
&& opline->extended_value == ZEND_SUB
&& ssa->ops[op_1].op1_def == v
&& opline->op2_type == IS_CONST
&& Z_TYPE_P(CT_CONSTANT_EX(op_array, opline->op2.constant)) == IS_LONG
&& Z_LVAL_P(CT_CONSTANT_EX(op_array, opline->op2.constant)) == 1
&& ssa->ops[op_1].op1_use >= 0
&& !(ssa->var_info[ssa->ops[op_1].op1_use].type & (MAY_BE_FALSE|MAY_BE_TRUE|MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))) {
// op_1: ASSIGN_SUB #?.CV [undef,null,int,foat] -> #v.CV, int(1) => PRE_DEC #?.CV ->#v.CV
opline->opcode = ZEND_PRE_DEC;
opline->extended_value = 0;
SET_UNUSED(opline->op2);
} else if (ssa->ops[op_1].op1_def == v
&& !RETURN_VALUE_USED(opline)
&& ssa->ops[op_1].op1_use >= 0
&& !(ssa->var_info[ssa->ops[op_1].op1_use].type & (MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF))
&& opline->opcode == ZEND_ASSIGN_OP
&& opline->extended_value != ZEND_CONCAT) {
// op_1: ASSIGN_OP #orig_var.CV [undef,null,bool,int,double] -> #v.CV, ? => #v.CV = ADD #orig_var.CV, ?
/* Reconstruct SSA */
ssa->ops[op_1].result_def = ssa->ops[op_1].op1_def;
ssa->ops[op_1].op1_def = -1;
/* Update opcode */
opline->opcode = opline->extended_value;
opline->extended_value = 0;
opline->result_type = opline->op1_type;
opline->result.var = opline->op1.var;
}
}
#if ZEND_DEBUG_DFA
ssa_verify_integrity(op_array, ssa, "after dfa");
#endif
if (remove_nops) {
zend_ssa_remove_nops(op_array, ssa, ctx);
#if ZEND_DEBUG_DFA
ssa_verify_integrity(op_array, ssa, "after nop");
#endif
}
}
if (ctx->debug_level & ZEND_DUMP_AFTER_DFA_PASS) {
zend_dump_op_array(op_array, ZEND_DUMP_SSA, "after dfa pass", ssa);
}
}
void zend_optimize_dfa(zend_op_array *op_array, zend_optimizer_ctx *ctx)
{
void *checkpoint = zend_arena_checkpoint(ctx->arena);
zend_ssa ssa;
if (zend_dfa_analyze_op_array(op_array, ctx, &ssa) != SUCCESS) {
zend_arena_release(&ctx->arena, checkpoint);
return;
}
zend_dfa_optimize_op_array(op_array, ctx, &ssa, NULL);
/* Destroy SSA */
zend_arena_release(&ctx->arena, checkpoint);
}
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