diff options
Diffstat (limited to 'Zend/Optimizer/compact_vars.c')
| -rw-r--r-- | Zend/Optimizer/compact_vars.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/Zend/Optimizer/compact_vars.c b/Zend/Optimizer/compact_vars.c new file mode 100644 index 0000000000..e70e189827 --- /dev/null +++ b/Zend/Optimizer/compact_vars.c @@ -0,0 +1,123 @@ +/* + +----------------------------------------------------------------------+ + | Zend Engine, Removing unused variables | + +----------------------------------------------------------------------+ + | 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: Nikita Popov <nikic@php.net> | + +----------------------------------------------------------------------+ +*/ + +#include "Optimizer/zend_optimizer_internal.h" +#include "zend_bitset.h" + +/* This pass removes all CVs and temporaries that are completely unused. It does *not* merge any CVs or TMPs. + * 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_vars_len = zend_bitset_len(op_array->last_var + op_array->T); + zend_bitset used_vars = ZEND_BITSET_ALLOCA(used_vars_len, use_heap1); + uint32_t *vars_map = do_alloca((op_array->last_var + op_array->T) * sizeof(uint32_t), use_heap2); + uint32_t num_cvs, num_tmps; + + /* Determine which CVs are used */ + zend_bitset_clear(used_vars, used_vars_len); + for (i = 0; i < op_array->last; i++) { + zend_op *opline = &op_array->opcodes[i]; + if (opline->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR)) { + zend_bitset_incl(used_vars, VAR_NUM(opline->op1.var)); + } + if (opline->op2_type & (IS_CV|IS_VAR|IS_TMP_VAR)) { + zend_bitset_incl(used_vars, VAR_NUM(opline->op2.var)); + } + if (opline->result_type & (IS_CV|IS_VAR|IS_TMP_VAR)) { + zend_bitset_incl(used_vars, VAR_NUM(opline->result.var)); + if (opline->opcode == ZEND_ROPE_INIT) { + uint32_t num = ((opline->extended_value * sizeof(zend_string*)) + (sizeof(zval) - 1)) / sizeof(zval); + while (num > 1) { + num--; + zend_bitset_incl(used_vars, VAR_NUM(opline->result.var) + num); + } + } + } + } + + num_cvs = 0; + for (i = 0; i < op_array->last_var; i++) { + if (zend_bitset_in(used_vars, i)) { + vars_map[i] = num_cvs++; + } else { + vars_map[i] = (uint32_t) -1; + } + } + + num_tmps = 0; + for (i = op_array->last_var; i < op_array->last_var + op_array->T; i++) { + if (zend_bitset_in(used_vars, i)) { + vars_map[i] = num_cvs + num_tmps++; + } else { + vars_map[i] = (uint32_t) -1; + } + } + + free_alloca(used_vars, use_heap1); + if (num_cvs == op_array->last_var && num_tmps == op_array->T) { + free_alloca(vars_map, use_heap2); + return; + } + + ZEND_ASSERT(num_cvs <= op_array->last_var); + ZEND_ASSERT(num_tmps <= op_array->T); + + /* 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|IS_VAR|IS_TMP_VAR)) { + opline->op1.var = NUM_VAR(vars_map[VAR_NUM(opline->op1.var)]); + } + if (opline->op2_type & (IS_CV|IS_VAR|IS_TMP_VAR)) { + opline->op2.var = NUM_VAR(vars_map[VAR_NUM(opline->op2.var)]); + } + if (opline->result_type & (IS_CV|IS_VAR|IS_TMP_VAR)) { + opline->result.var = NUM_VAR(vars_map[VAR_NUM(opline->result.var)]); + } + } + + /* Update CV name table */ + if (num_cvs != op_array->last_var) { + if (num_cvs) { + zend_string **names = safe_emalloc(sizeof(zend_string *), num_cvs, 0); + for (i = 0; i < op_array->last_var; i++) { + if (vars_map[i] != (uint32_t) -1) { + names[vars_map[i]] = op_array->vars[i]; + } else { + zend_string_release_ex(op_array->vars[i], 0); + } + } + efree(op_array->vars); + op_array->vars = names; + } else { + for (i = 0; i < op_array->last_var; i++) { + zend_string_release_ex(op_array->vars[i], 0); + } + efree(op_array->vars); + op_array->vars = NULL; + } + op_array->last_var = num_cvs; + } + + op_array->T = num_tmps; + + free_alloca(vars_map, use_heap2); +} |