text: /*
     +----------------------------------------------------------------------+
     | Zend OPcache                                                         |
     +----------------------------------------------------------------------+
     | Copyright (c) 1998-2015 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: Andi Gutmans <andi@zend.com>                                |
     |          Zeev Suraski <zeev@zend.com>                                |
     |          Stanislav Malyshev <stas@zend.com>                          |
     |          Dmitry Stogov <dmitry@zend.com>                             |
     +----------------------------------------------------------------------+
  */
  
  /* pass 10:
   * - remove NOPs
   */
  
  #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"
  
  void zend_optimizer_nop_removal(zend_op_array *op_array)
  {
  	zend_op *end, *opline;
  	uint32_t new_count, i, shift;
  	int j;
  	uint32_t *shiftlist;
  	ALLOCA_FLAG(use_heap);
  
  	shiftlist = (uint32_t *)DO_ALLOCA(sizeof(uint32_t) * op_array->last);
  	i = new_count = shift = 0;
  	end = op_array->opcodes + op_array->last;
  	for (opline = op_array->opcodes; opline < end; opline++) {
  
  		/* GOTO target is unresolved yet. We can't optimize. */
  		if (opline->opcode == ZEND_GOTO &&
  			Z_TYPE(ZEND_OP2_LITERAL(opline)) != IS_LONG) {
  			/* TODO: in general we can avoid this restriction */
  			FREE_ALLOCA(shiftlist);
  			return;
  		}
  
  		/* Kill JMP-over-NOP-s */
  		if (opline->opcode == ZEND_JMP && ZEND_OP1(opline).opline_num > i) {
  			/* check if there are only NOPs under the branch */
  			zend_op *target = op_array->opcodes + ZEND_OP1(opline).opline_num - 1;
  
  			while (target->opcode == ZEND_NOP) {
  				target--;
  			}
  			if (target == opline) {
  				/* only NOPs */
  				opline->opcode = ZEND_NOP;
  			}
  		}
  
  		shiftlist[i++] = shift;
  		if (opline->opcode == ZEND_NOP) {
  			shift++;
  		} else {
  			if (shift) {
  				op_array->opcodes[new_count] = *opline;
  			}
  			new_count++;
  		}
  	}
  
  	if (shift) {
  		op_array->last = new_count;
  		end = op_array->opcodes + op_array->last;
  
  		/* update JMPs */
  		for (opline = op_array->opcodes; opline<end; opline++) {
  			switch (opline->opcode) {
  				case ZEND_JMP:
  				case ZEND_GOTO:
  				case ZEND_FAST_CALL:
  					ZEND_OP1(opline).opline_num -= shiftlist[ZEND_OP1(opline).opline_num];
  					break;
  				case ZEND_JMPZ:
  				case ZEND_JMPNZ:
  				case ZEND_JMPZ_EX:
  				case ZEND_JMPNZ_EX:
  				case ZEND_FE_FETCH_R:
  				case ZEND_FE_FETCH_RW:
  				case ZEND_FE_RESET_R:
  				case ZEND_FE_RESET_RW:
  				case ZEND_NEW:
  				case ZEND_JMP_SET:
  				case ZEND_COALESCE:
  				case ZEND_ASSERT_CHECK:
  					ZEND_OP2(opline).opline_num -= shiftlist[ZEND_OP2(opline).opline_num];
  					break;
  				case ZEND_JMPZNZ:
  					ZEND_OP2(opline).opline_num -= shiftlist[ZEND_OP2(opline).opline_num];
  					opline->extended_value -= shiftlist[opline->extended_value];
  					break;
  				case ZEND_CATCH:
  					opline->extended_value -= shiftlist[opline->extended_value];
  					break;
  			}
  		}
  
  		/* update brk/cont array */
  		for (j = 0; j < op_array->last_brk_cont; j++) {
  			op_array->brk_cont_array[j].brk -= shiftlist[op_array->brk_cont_array[j].brk];
  			op_array->brk_cont_array[j].cont -= shiftlist[op_array->brk_cont_array[j].cont];
  			op_array->brk_cont_array[j].start -= shiftlist[op_array->brk_cont_array[j].start];
  		}
  
  		/* 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->early_binding != (uint32_t)-1) {
  			uint32_t *opline_num = &op_array->early_binding;
  
  			do {
  				*opline_num -= shiftlist[*opline_num];
  				opline_num = &ZEND_RESULT(&op_array->opcodes[*opline_num]).opline_num;
  			} while (*opline_num != (uint32_t)-1);
  		}
  	}
  	FREE_ALLOCA(shiftlist);
  }
  