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Fixed incorect constant conditional jump elimination

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This commit is contained in:
Dmitry Stogov
2017-09-04 19:11:17 +03:00
parent 97b3cce755
commit ea734e2ac2
7 changed files with 202 additions and 73 deletions
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3
NEWS
View File

@@ -5,6 +5,9 @@ PHP NEWS
- GD:
. Fixed bug #75139 (libgd/gd_interpolation.c:1786: suspicious if ?). (cmb)
- Opcache
. Fixed incorect constant conditional jump elimination. (Dmitry)
- OpenSSL
. Automatically load OpenSSL configuration file. (Jakub Zelenka)

46
ext/opcache/Optimizer/block_pass.c
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@@ -195,6 +195,52 @@ static void zend_optimize_block(zend_basic_block *block, zend_op_array *op_array
VAR_SOURCE(op1) = NULL;
literal_dtor(&ZEND_OP1_LITERAL(src));
MAKE_NOP(src);
switch (opline->opcode) {
case ZEND_JMPZ:
if (zend_is_true(&ZEND_OP1_LITERAL(opline))) {
MAKE_NOP(opline);
DEL_SOURCE(block, block->successors[0]);
block->successors_count = 1;
block->successors[0] = block->successors[1];
} else {
opline->opcode = ZEND_JMP;
COPY_NODE(opline->op1, opline->op2);
DEL_SOURCE(block, block->successors[1]);
block->successors_count = 1;
}
break;
case ZEND_JMPNZ:
if (zend_is_true(&ZEND_OP1_LITERAL(opline))) {
opline->opcode = ZEND_JMP;
COPY_NODE(opline->op1, opline->op2);
DEL_SOURCE(block, block->successors[1]);
block->successors_count = 1;
} else {
MAKE_NOP(opline);
DEL_SOURCE(block, block->successors[0]);
block->successors_count = 1;
block->successors[0] = block->successors[1];
}
break;
case ZEND_JMPZNZ:
if (zend_is_true(&ZEND_OP1_LITERAL(opline))) {
zend_op *target_opline = ZEND_OFFSET_TO_OPLINE(opline, opline->extended_value);
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target_opline);
DEL_SOURCE(block, block->successors[0]);
block->successors[0] = block->successors[1];
} else {
zend_op *target_opline = ZEND_OP2_JMP_ADDR(opline);
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target_opline);
DEL_SOURCE(block, block->successors[0]);
}
block->successors_count = 1;
opline->op1_type = IS_UNUSED;
opline->extended_value = 0;
opline->opcode = ZEND_JMP;
break;
default:
break;
}
} else {
zval_ptr_dtor_nogc(&c);
}

87
ext/opcache/Optimizer/sccp.c
View File

@@ -234,6 +234,93 @@ static zend_bool try_replace_op1(
zval zv;
ZVAL_COPY(&zv, value);
if (zend_optimizer_update_op1_const(ctx->scdf.op_array, opline, &zv)) {
/* Reconstruct SSA */
int num;
zend_basic_block *block;
switch (opline->opcode) {
case ZEND_JMPZ:
if (zend_is_true(&zv)) {
MAKE_NOP(opline);
num = ctx->scdf.ssa->cfg.map[opline - ctx->scdf.op_array->opcodes];
block = &ctx->scdf.ssa->cfg.blocks[num];
if (block->successors_count == 2) {
if (block->successors[1] != block->successors[0]) {
zend_ssa_remove_predecessor(ctx->scdf.ssa, num, block->successors[0]);
}
block->successors_count = 1;
block->successors[0] = block->successors[1];
}
} else {
opline->opcode = ZEND_JMP;
COPY_NODE(opline->op1, opline->op2);
num = ctx->scdf.ssa->cfg.map[opline - ctx->scdf.op_array->opcodes];
block = &ctx->scdf.ssa->cfg.blocks[num];
if (block->successors_count == 2) {
if (block->successors[1] != block->successors[0]) {
zend_ssa_remove_predecessor(ctx->scdf.ssa, num, block->successors[1]);
}
block->successors_count = 1;
}
}
break;
case ZEND_JMPNZ:
if (zend_is_true(&zv)) {
opline->opcode = ZEND_JMP;
COPY_NODE(opline->op1, opline->op2);
num = ctx->scdf.ssa->cfg.map[opline - ctx->scdf.op_array->opcodes];
block = &ctx->scdf.ssa->cfg.blocks[num];
if (block->successors_count == 2) {
if (block->successors[1] != block->successors[0]) {
zend_ssa_remove_predecessor(ctx->scdf.ssa, num, block->successors[1]);
}
block->successors_count = 1;
}
} else {
MAKE_NOP(opline);
num = ctx->scdf.ssa->cfg.map[opline - ctx->scdf.op_array->opcodes];
block = &ctx->scdf.ssa->cfg.blocks[num];
if (block->successors_count == 2) {
if (block->successors[1] != block->successors[0]) {
zend_ssa_remove_predecessor(ctx->scdf.ssa, num, block->successors[0]);
}
block->successors_count = 1;
block->successors[0] = block->successors[1];
}
}
break;
case ZEND_JMPZNZ:
if (zend_is_true(&zv)) {
zend_op *target_opline = ZEND_OFFSET_TO_OPLINE(opline, opline->extended_value);
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target_opline);
num = ctx->scdf.ssa->cfg.map[opline - ctx->scdf.op_array->opcodes];
block = &ctx->scdf.ssa->cfg.blocks[num];
if (block->successors_count == 2) {
if (block->successors[1] != block->successors[0]) {
zend_ssa_remove_predecessor(ctx->scdf.ssa, num, block->successors[0]);
}
block->successors_count = 1;
block->successors[0] = block->successors[1];
}
} else {
zend_op *target_opline = ZEND_OP2_JMP_ADDR(opline);
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target_opline);
num = ctx->scdf.ssa->cfg.map[opline - ctx->scdf.op_array->opcodes];
block = &ctx->scdf.ssa->cfg.blocks[num];
if (block->successors_count == 2) {
if (block->successors[1] != block->successors[0]) {
zend_ssa_remove_predecessor(ctx->scdf.ssa, num, block->successors[1]);
}
block->successors_count = 1;
}
}
opline->op1_type = IS_UNUSED;
opline->extended_value = 0;
opline->opcode = ZEND_JMP;
break;
default:
break;
}
return 1;
} else {
// TODO: check the following special cases ???

34
ext/opcache/Optimizer/zend_optimizer.c
View File

@@ -258,41 +258,7 @@ int zend_optimizer_update_op1_const(zend_op_array *op_array,
zend_op *opline,
zval *val)
{
zend_op *target_opline;
switch (opline->opcode) {
case ZEND_JMPZ:
if (zend_is_true(val)) {
MAKE_NOP(opline);
} else {
opline->opcode = ZEND_JMP;
COPY_NODE(opline->op1, opline->op2);
opline->op2_type = IS_UNUSED;
}
zval_ptr_dtor_nogc(val);
return 1;
case ZEND_JMPNZ:
if (zend_is_true(val)) {
opline->opcode = ZEND_JMP;
COPY_NODE(opline->op1, opline->op2);
opline->op2_type = IS_UNUSED;
} else {
MAKE_NOP(opline);
}
zval_ptr_dtor_nogc(val);
return 1;
case ZEND_JMPZNZ:
if (zend_is_true(val)) {
target_opline = ZEND_OFFSET_TO_OPLINE(opline, opline->extended_value);
} else {
target_opline = ZEND_OP2_JMP_ADDR(opline);
}
ZEND_SET_OP_JMP_ADDR(opline, opline->op1, target_opline);
opline->op1_type = IS_UNUSED;
opline->extended_value = 0;
opline->opcode = ZEND_JMP;
zval_ptr_dtor_nogc(val);
return 1;
case ZEND_FREE:
MAKE_NOP(opline);
zval_ptr_dtor_nogc(val);

86
ext/opcache/Optimizer/zend_ssa.c
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@@ -1339,6 +1339,52 @@ void zend_ssa_remove_uses_of_var(zend_ssa *ssa, int var_num) /* {{{ */
}
/* }}} */
void zend_ssa_remove_predecessor(zend_ssa *ssa, int from, int to) /* {{{ */
{
zend_basic_block *next_block = &ssa->cfg.blocks[to];
zend_ssa_block *next_ssa_block = &ssa->blocks[to];
zend_ssa_phi *phi;
int j;
/* Find at which predecessor offset this block is referenced */
int pred_offset = -1;
int *predecessors = &ssa->cfg.predecessors[next_block->predecessor_offset];
for (j = 0; j < next_block->predecessors_count; j++) {
if (predecessors[j] == from) {
pred_offset = j;
break;
}
}
/* If there are duplicate successors, the predecessors may have been removed in
* a previous iteration already. */
if (pred_offset == -1) {
return;
}
/* For phis in successor blocks, remove the operands associated with this block */
for (phi = next_ssa_block->phis; phi; phi = phi->next) {
if (phi->pi >= 0) {
if (phi->pi == from) {
zend_ssa_remove_uses_of_var(ssa, phi->ssa_var);
zend_ssa_remove_phi(ssa, phi);
}
} else {
ZEND_ASSERT(phi->sources[pred_offset] >= 0);
zend_ssa_remove_phi_source(ssa, phi, pred_offset, next_block->predecessors_count);
}
}
/* Remove this predecessor */
next_block->predecessors_count--;
if (pred_offset < next_block->predecessors_count) {
predecessors = &ssa->cfg.predecessors[next_block->predecessor_offset + pred_offset];
memmove(predecessors, predecessors + 1, (next_block->predecessors_count - pred_offset) * sizeof(uint32_t));
}
}
/* }}} */
void zend_ssa_remove_block(zend_op_array *op_array, zend_ssa *ssa, int i) /* {{{ */
{
zend_basic_block *block = &ssa->cfg.blocks[i];
@@ -1369,45 +1415,7 @@ void zend_ssa_remove_block(zend_op_array *op_array, zend_ssa *ssa, int i) /* {{{
}
for (s = 0; s < block->successors_count; s++) {
zend_basic_block *next_block = &ssa->cfg.blocks[block->successors[s]];
zend_ssa_block *next_ssa_block = &ssa->blocks[block->successors[s]];
zend_ssa_phi *phi;
/* Find at which predecessor offset this block is referenced */
int pred_offset = -1;
predecessors = &ssa->cfg.predecessors[next_block->predecessor_offset];
for (j = 0; j < next_block->predecessors_count; j++) {
if (predecessors[j] == i) {
pred_offset = j;
break;
}
}
/* If there are duplicate successors, the predecessors may have been removed in
* a previous iteration already. */
if (pred_offset == -1) {
continue;
}
/* For phis in successor blocks, remove the operands associated with this block */
for (phi = next_ssa_block->phis; phi; phi = phi->next) {
if (phi->pi >= 0) {
if (phi->pi == i) {
zend_ssa_remove_uses_of_var(ssa, phi->ssa_var);
zend_ssa_remove_phi(ssa, phi);
}
} else {
ZEND_ASSERT(phi->sources[pred_offset] >= 0);
zend_ssa_remove_phi_source(ssa, phi, pred_offset, next_block->predecessors_count);
}
}
/* Remove this predecessor */
next_block->predecessors_count--;
if (pred_offset < next_block->predecessors_count) {
predecessors = &ssa->cfg.predecessors[next_block->predecessor_offset + pred_offset];
memmove(predecessors, predecessors + 1, (next_block->predecessors_count - pred_offset) * sizeof(uint32_t));
}
zend_ssa_remove_predecessor(ssa, i, block->successors[s]);
}
/* Remove successors of predecessors */

1
ext/opcache/Optimizer/zend_ssa.h
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@@ -139,6 +139,7 @@ int zend_build_ssa(zend_arena **arena, const zend_script *script, const zend_op_
int zend_ssa_compute_use_def_chains(zend_arena **arena, const zend_op_array *op_array, zend_ssa *ssa);
int zend_ssa_unlink_use_chain(zend_ssa *ssa, int op, int var);
void zend_ssa_remove_predecessor(zend_ssa *ssa, int from, int to);
void zend_ssa_remove_instr(zend_ssa *ssa, zend_op *opline, zend_ssa_op *ssa_op);
void zend_ssa_remove_phi(zend_ssa *ssa, zend_ssa_phi *phi);
void zend_ssa_remove_uses_of_var(zend_ssa *ssa, int var_num);

18
ext/opcache/tests/jmp_elim_001.phpt Normal file
View File

@@ -0,0 +1,18 @@
--TEST--
Edge-cases in constant conditional jump elimination
--SKIPIF--
<?php if (PHP_INT_SIZE != 8) die("skip for machines with 64-bit longs"); ?>
<?php require_once('skipif.inc'); ?>
--FILE--
<?php
$webserver = "Apache";
$cpuArc = "x86_64";
$archName = (strstr($cpuArc, "64") || PHP_INT_SIZE === 8) ? "64" : "32";
$info = array('os' => PHP_OS,
'phpversion' => phpversion(),
'arch' => $archName,
'webserver' =>$webserver);
header('Content-Type: application/json');
echo json_encode($info) . "\n";
--EXPECT--
{"os":"Linux","phpversion":"7.2.0-dev","arch":"64","webserver":"Apache"}