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|
/*
+----------------------------------------------------------------------+
| Zend Engine, Removing unused variables |
+----------------------------------------------------------------------+
| Copyright (c) 1998-2017 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: Nikita Popov <nikic@php.net> |
+----------------------------------------------------------------------+
*/
#include "ZendAccelerator.h"
#include "Optimizer/zend_optimizer_internal.h"
#include "zend_bitset.h"
/* This pass removes all CVs that are completely unused. It does *not* merge any CVs.
* This pass does not operate on SSA form anymore. */
void zend_optimizer_compact_vars(zend_op_array *op_array) {
int i;
ALLOCA_FLAG(use_heap1);
ALLOCA_FLAG(use_heap2);
uint32_t used_cvs_len = zend_bitset_len(op_array->last_var);
zend_bitset used_cvs = ZEND_BITSET_ALLOCA(used_cvs_len, use_heap1);
uint32_t *cv_map = do_alloca(op_array->last_var * sizeof(uint32_t), use_heap2);
uint32_t num_cvs, tmp_offset;
/* Determine which CVs are used */
zend_bitset_clear(used_cvs, used_cvs_len);
for (i = 0; i < op_array->last; i++) {
zend_op *opline = &op_array->opcodes[i];
if (opline->op1_type == IS_CV) {
zend_bitset_incl(used_cvs, VAR_NUM(opline->op1.var));
}
if (opline->op2_type == IS_CV) {
zend_bitset_incl(used_cvs, VAR_NUM(opline->op2.var));
}
if (opline->result_type == IS_CV) {
zend_bitset_incl(used_cvs, VAR_NUM(opline->result.var));
}
}
num_cvs = 0;
for (i = 0; i < op_array->last_var; i++) {
if (zend_bitset_in(used_cvs, i)) {
cv_map[i] = num_cvs++;
} else {
cv_map[i] = (uint32_t) -1;
}
}
free_alloca(used_cvs, use_heap1);
if (num_cvs == op_array->last_var) {
free_alloca(cv_map, use_heap2);
return;
}
ZEND_ASSERT(num_cvs < op_array->last_var);
tmp_offset = op_array->last_var - num_cvs;
/* Update CV and TMP references in opcodes */
for (i = 0; i < op_array->last; i++) {
zend_op *opline = &op_array->opcodes[i];
if (opline->op1_type == IS_CV) {
opline->op1.var = NUM_VAR(cv_map[VAR_NUM(opline->op1.var)]);
} else if (opline->op1_type & (IS_VAR|IS_TMP_VAR)) {
opline->op1.var -= sizeof(zval) * tmp_offset;
}
if (opline->op2_type == IS_CV) {
opline->op2.var = NUM_VAR(cv_map[VAR_NUM(opline->op2.var)]);
} else if (opline->op2_type & (IS_VAR|IS_TMP_VAR)) {
opline->op2.var -= sizeof(zval) * tmp_offset;
}
if (opline->result_type == IS_CV) {
opline->result.var = NUM_VAR(cv_map[VAR_NUM(opline->result.var)]);
} else if (opline->result_type & (IS_VAR|IS_TMP_VAR)) {
opline->result.var -= sizeof(zval) * tmp_offset;
}
}
/* Update TMP references in live ranges */
if (op_array->live_range) {
for (i = 0; i < op_array->last_live_range; i++) {
op_array->live_range[i].var -= sizeof(zval) * tmp_offset;
}
}
/* Update CV name table */
if (num_cvs) {
zend_string **names = safe_emalloc(sizeof(zend_string *), num_cvs, 0);
for (i = 0; i < op_array->last_var; i++) {
if (cv_map[i] != (uint32_t) -1) {
names[cv_map[i]] = op_array->vars[i];
} else {
zend_string_release(op_array->vars[i]);
}
}
efree(op_array->vars);
op_array->vars = names;
} else {
for (i = 0; i < op_array->last_var; i++) {
zend_string_release(op_array->vars[i]);
}
efree(op_array->vars);
op_array->vars = NULL;
}
op_array->last_var = num_cvs;
free_alloca(cv_map, use_heap2);
}
|
