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Fix GH-17577: JIT packed type guard crash #17584

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Fix GH-17577: JIT packed type guard crash #17584

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f7b7472
Fix GH-17577: JIT packed type guard crash
nielsdos Jan 26, 2025
a99025c
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nielsdos Jan 31, 2025
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21 changes: 15 additions & 6 deletions ext/opcache/jit/zend_jit_trace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1745,7 +1745,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin
if (!(orig_op1_type & IS_TRACE_PACKED)) {
zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];

if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
&& (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
info->type |= MAY_BE_PACKED_GUARD;
info->type &= ~MAY_BE_ARRAY_PACKED;
}
Expand All @@ -1754,7 +1755,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin
&& val_type != IS_UNDEF) {
zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];

if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
&& (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
info->type |= MAY_BE_PACKED_GUARD;
info->type &= ~(MAY_BE_ARRAY_NUMERIC_HASH|MAY_BE_ARRAY_STRING_HASH);
}
Expand Down Expand Up @@ -1833,7 +1835,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin

zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];

if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
&& (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
info->type |= MAY_BE_PACKED_GUARD;
if (orig_op1_type & IS_TRACE_PACKED) {
info->type &= ~(MAY_BE_ARRAY_NUMERIC_HASH|MAY_BE_ARRAY_STRING_HASH);
Expand Down Expand Up @@ -1935,7 +1938,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin

zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];

if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
&& (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
info->type |= MAY_BE_PACKED_GUARD;
if (orig_op1_type & IS_TRACE_PACKED) {
info->type &= ~(MAY_BE_ARRAY_NUMERIC_HASH|MAY_BE_ARRAY_STRING_HASH);
Expand Down Expand Up @@ -1965,7 +1969,8 @@ static zend_ssa *zend_jit_trace_build_tssa(zend_jit_trace_rec *trace_buffer, uin

zend_ssa_var_info *info = &tssa->var_info[tssa->ops[idx].op1_use];

if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)) {
if (MAY_BE_PACKED(info->type) && MAY_BE_HASH(info->type)
&& (info->type & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY) {
info->type |= MAY_BE_PACKED_GUARD;
info->type &= ~MAY_BE_ARRAY_PACKED;
}
Expand Down Expand Up @@ -4164,10 +4169,14 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
if ((info & MAY_BE_PACKED_GUARD) != 0
&& (trace_buffer->stop == ZEND_JIT_TRACE_STOP_LOOP
|| trace_buffer->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_CALL
|| trace_buffer->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_RET)
|| (trace_buffer->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_RET
&& (opline-1)->result_type == IS_VAR
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It's better to keep the conditions exactly the same. We don't have IS_VAR check above (when we generate type guard). In general, Optimizer may fuse DO_FCALL with the following ASSIGN to IS_CV (I'm not sure if this is enabled or not).

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Maybe I miss something, but I got this from here:

php-src/ext/opcache/jit/zend_jit_trace.c

Lines 4148 to 4150 in a99025c

|| (trace_buffer->stop == ZEND_JIT_TRACE_STOP_RECURSIVE_RET
&& (opline-1)->result_type == IS_VAR
&& EX_VAR_TO_NUM((opline-1)->result.var) == i))

So I'm not sure I understand why the check for IS_VAR is fine there for the type guard, but not for the packed type guard.

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I see. I looked into the master branch code.
So keep IS_VAR in PHP-8.3 and remove it in PHP-8.4 and master.

&& EX_VAR_TO_NUM((opline-1)->result.var) == i))
&& (ssa->vars[i].use_chain != -1
|| (ssa->vars[i].phi_use_chain
&& !(ssa->var_info[ssa->vars[i].phi_use_chain->ssa_var].type & MAY_BE_PACKED_GUARD)))) {
ZEND_ASSERT(STACK_TYPE(stack, i) == IS_ARRAY);

if (!zend_jit_packed_guard(&dasm_state, opline, EX_NUM_TO_VAR(i), info)) {
goto jit_failure;
}
Expand Down
27 changes: 27 additions & 0 deletions ext/opcache/tests/jit/gh17577.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
--TEST--
GH-17577 (JIT packed type guard crash)
--EXTENSIONS--
opcache
--INI--
opcache.jit_buffer_size=16M
opcache.jit_hot_func=1
--FILE--
<?php
$a = array(
array(1,2,3),
0,
);
function my_dump($var) {
}
foreach($a as $b) {
for ($i = 0; $i < 3; $i++) {
my_dump($b[$i]);
}
}
?>
--EXPECTF--
Warning: Trying to access array offset on int in %s on line %d

Warning: Trying to access array offset on int in %s on line %d

Warning: Trying to access array offset on int in %s on line %d
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