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[RFC] OPcache Static Cache Implementation #22052

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85 changes: 85 additions & 0 deletions Zend/tests/assign_obj_ref_track_mutation_order.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,85 @@
--TEST--
ASSIGN_OBJ_REF tracks object mutations before freeing operands
--SKIPIF--
<?php
$zendDir = dirname(__DIR__);
if (!is_file($zendDir . '/zend_vm_def.h') || !is_file($zendDir . '/zend_vm_execute.h')) {
die('skip source tree required');
}
?>
--FILE--
<?php

function assertAssignObjRefTrackingOrder(string $section, string $label): bool
{
$trackPos = strpos($section, 'ZEND_MAYBE_TRACK_OBJECT_MUTATION(zobj);');
$freeNeedles = [
'FREE_OP1();',
'FREE_OP2();',
'FREE_OP_DATA();',
'zval_ptr_dtor_nogc(EX_VAR(opline->op1.var));',
'zval_ptr_dtor_nogc(EX_VAR(opline->op2.var));',
'zval_ptr_dtor_nogc(EX_VAR((opline+1)->op1.var));',
];
$freePositions = [];

foreach ($freeNeedles as $needle) {
$pos = strpos($section, $needle);
if ($pos !== false) {
$freePositions[] = $pos;
}
}

if ($trackPos === false) {
throw new RuntimeException($label . ' is missing the expected ASSIGN_OBJ_REF sequence');
}

if ($freePositions === []) {
return false;
}

if ($trackPos > min($freePositions)) {
throw new RuntimeException($label . ' tracks object mutation after freeing operands');
}

return true;
}

$zendDir = dirname(__DIR__);

$vmDef = file_get_contents($zendDir . '/zend_vm_def.h');
$defStart = strpos($vmDef, 'ZEND_VM_HANDLER(32, ZEND_ASSIGN_OBJ_REF');
$defEnd = strpos($vmDef, 'ZEND_VM_HANDLER(33, ZEND_ASSIGN_STATIC_PROP_REF');
if ($defStart === false || $defEnd === false) {
throw new RuntimeException('Unable to locate ZEND_ASSIGN_OBJ_REF in zend_vm_def.h');
}

if (!assertAssignObjRefTrackingOrder(substr($vmDef, $defStart, $defEnd - $defStart), 'zend_vm_def.h')) {
throw new RuntimeException('zend_vm_def.h ASSIGN_OBJ_REF unexpectedly has no operand frees');
}

$vmExecute = file_get_contents($zendDir . '/zend_vm_execute.h');
$sections = preg_split('/(?=static ZEND_OPCODE_HANDLER_RET )/', $vmExecute);
$checked = 0;

foreach ($sections as $section) {
$headerEnd = strpos($section, "\n");
$label = $headerEnd === false ? 'zend_vm_execute.h ASSIGN_OBJ_REF handler' : trim(substr($section, 0, $headerEnd));
if (!preg_match('/\bZEND_ASSIGN_OBJ_REF_[A-Z0-9_]+_HANDLER\b/', $label)) {
continue;
}

if (assertAssignObjRefTrackingOrder($section, $label)) {
$checked++;
}
}

if ($checked === 0) {
throw new RuntimeException('Unable to locate generated ZEND_ASSIGN_OBJ_REF handlers in zend_vm_execute.h');
}

echo "OK\n";

?>
--EXPECT--
OK
78 changes: 78 additions & 0 deletions Zend/tests/tracked_mutation_hook_safety.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,78 @@
--TEST--
Tracked mutation hooks are called through defensive helpers
--SKIPIF--
<?php
$zendDir = dirname(__DIR__);
foreach (['zend_execute.h', 'zend_execute.c', 'zend_vm_def.h', 'zend_vm_execute.h'] as $file) {
if (!is_file($zendDir . '/' . $file)) {
die('skip source tree required');
}
}
?>
--FILE--
<?php

function sourceSection(string $source, string $start, string $end, string $label): string
{
$startPos = strpos($source, $start);
$endPos = strpos($source, $end, $startPos === false ? 0 : $startPos);

if ($startPos === false || $endPos === false || $endPos <= $startPos) {
throw new RuntimeException('Unable to locate ' . $label);
}

return substr($source, $startPos, $endPos - $startPos);
}

$zendDir = dirname(__DIR__);
$executeH = file_get_contents($zendDir . '/zend_execute.h');
$executeC = file_get_contents($zendDir . '/zend_execute.c');

if (!str_contains($executeH, 'static zend_always_inline bool zend_maybe_track_hash_mutation(HashTable *ht, bool publish)')) {
throw new RuntimeException('Missing hash mutation helper');
}

if (!str_contains($executeH, 'zend_tracked_hash_mutation_hook != NULL')) {
throw new RuntimeException('Hash mutation helper does not guard the hook pointer');
}

foreach (['zend_execute.c', 'zend_vm_def.h', 'zend_vm_execute.h'] as $file) {
$source = file_get_contents($zendDir . '/' . $file);
if (str_contains($source, 'zend_tracked_hash_mutation_hook(')) {
throw new RuntimeException($file . ' calls zend_tracked_hash_mutation_hook() directly');
}
}

if (!str_contains($executeC, 'zobj != NULL && zend_tracked_object_mutation_hook != NULL && EG(exception) == NULL')) {
throw new RuntimeException('Object mutation slow path does not guard the hook pointer');
}

if (!str_contains($executeC, 'zobj != NULL && zend_tracked_object_mutation_hook != NULL && EG(exception) == NULL && value != &EG(error_zval)')) {
throw new RuntimeException('Object mutation with-value slow path does not guard the hook pointer');
}

$assign = sourceSection(
$executeH,
'static zend_always_inline zval* zend_assign_to_variable(',
'static zend_always_inline zval* zend_assign_to_variable_ex(',
'zend_assign_to_variable()'
);
if (substr_count($assign, 'zend_maybe_track_reference_update(updated_ref);') < 2) {
throw new RuntimeException('zend_assign_to_variable() does not notify reference updates');
}

$assignEx = sourceSection(
$executeH,
'static zend_always_inline zval* zend_assign_to_variable_ex(',
'static zend_always_inline void zend_class_static_update(',
'zend_assign_to_variable_ex()'
);
if (substr_count($assignEx, 'zend_maybe_track_reference_update(updated_ref);') < 2) {
throw new RuntimeException('zend_assign_to_variable_ex() does not notify reference updates');
}

echo "OK\n";

?>
--EXPECT--
OK
9 changes: 9 additions & 0 deletions Zend/zend.c
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Expand Up @@ -96,6 +96,13 @@ ZEND_API zend_string *(*zend_resolve_path)(zend_string *filename);
ZEND_API zend_result (*zend_post_startup_cb)(void) = NULL;
ZEND_API void (*zend_post_shutdown_cb)(void) = NULL;
ZEND_API void (*zend_accel_schedule_restart_hook)(int reason) = NULL;
ZEND_API void (*zend_class_init_statics_hook)(zend_class_entry *ce) = NULL;
ZEND_API void (*zend_function_init_statics_hook)(zend_execute_data *execute_data) = NULL;
ZEND_API void (*zend_class_static_access_hook)(zend_class_entry *ce) = NULL;
ZEND_API void (*zend_class_static_update_hook)(zend_class_entry *ce) = NULL;
ZEND_API void (*zend_tracked_reference_update_hook)(zend_reference *ref) = NULL;
ZEND_API bool (*zend_tracked_hash_mutation_hook)(HashTable *ht, bool publish) = NULL;
ZEND_API void (*zend_tracked_object_mutation_hook)(zend_object *obj) = NULL;
ZEND_ATTRIBUTE_NONNULL ZEND_API zend_result (*zend_random_bytes)(void *bytes, size_t size, char *errstr, size_t errstr_size) = NULL;
ZEND_ATTRIBUTE_NONNULL ZEND_API void (*zend_random_bytes_insecure)(zend_random_bytes_insecure_state *state, void *bytes, size_t size) = NULL;

Expand Down Expand Up @@ -819,6 +826,8 @@ static void executor_globals_ctor(zend_executor_globals *executor_globals) /* {{
#endif
executor_globals->saved_fpu_cw_ptr = NULL;
executor_globals->active = false;
executor_globals->static_cache_class_access_active = false;
executor_globals->tracked_mutation_hooks_active = false;
executor_globals->bailout = NULL;
executor_globals->error_handling = EH_NORMAL;
executor_globals->exception_class = NULL;
Expand Down
11 changes: 11 additions & 0 deletions Zend/zend.h
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Original file line number Diff line number Diff line change
Expand Up @@ -386,6 +386,17 @@ extern ZEND_API void (*zend_post_shutdown_cb)(void);

extern ZEND_API void (*zend_accel_schedule_restart_hook)(int reason);

/* These hooks are used by OPcache Static Cache to restore, publish, and track
* selected VolatileStatic and PersistentStatic state across requests. They remain
* NULL when the static-cache subsystem is not active. */
extern ZEND_API void (*zend_class_init_statics_hook)(zend_class_entry *ce);
extern ZEND_API void (*zend_function_init_statics_hook)(zend_execute_data *execute_data);
extern ZEND_API void (*zend_class_static_access_hook)(zend_class_entry *ce);
extern ZEND_API void (*zend_class_static_update_hook)(zend_class_entry *ce);
extern ZEND_API void (*zend_tracked_reference_update_hook)(zend_reference *ref);
extern ZEND_API bool (*zend_tracked_hash_mutation_hook)(HashTable *ht, bool publish);
extern ZEND_API void (*zend_tracked_object_mutation_hook)(zend_object *obj);

ZEND_API ZEND_COLD void zend_error(int type, const char *format, ...) ZEND_ATTRIBUTE_FORMAT(printf, 2, 3);
ZEND_API ZEND_COLD ZEND_NORETURN void zend_error_noreturn(int type, const char *format, ...) ZEND_ATTRIBUTE_FORMAT(printf, 2, 3);
ZEND_API ZEND_COLD ZEND_NORETURN void zend_error_noreturn_unchecked(int type, const char *format, ...);
Expand Down
42 changes: 42 additions & 0 deletions Zend/zend_execute.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2908,6 +2908,11 @@ static zend_always_inline void zend_fetch_dimension_address(zval *result, zval *

if (EXPECTED(Z_TYPE_P(container) == IS_ARRAY)) {
try_array:
if (UNEXPECTED((type == BP_VAR_W || type == BP_VAR_RW || type == BP_VAR_UNSET) &&
EG(tracked_mutation_hooks_active))
) {
zend_maybe_track_hash_mutation(Z_ARRVAL_P(container), false);
}
SEPARATE_ARRAY(container);
fetch_from_array:
if (dim == NULL) {
Expand Down Expand Up @@ -3507,6 +3512,20 @@ static zend_never_inline bool zend_handle_fetch_obj_flags(
return 1;
}

static zend_always_inline void zend_track_property_array_indirect_mutation(zval *ptr, int type)
{
zval *tracked = ptr;

if (UNEXPECTED((type == BP_VAR_W || type == BP_VAR_RW || type == BP_VAR_UNSET) &&
EG(tracked_mutation_hooks_active))
) {
ZVAL_DEREF(tracked);
if (Z_TYPE_P(tracked) == IS_ARRAY) {
zend_maybe_track_hash_mutation(Z_ARRVAL_P(tracked), false);
}
}
}

static zend_always_inline void zend_fetch_property_address(
zval *result,
const zval *container,
Expand Down Expand Up @@ -3591,6 +3610,7 @@ static zend_always_inline void zend_fetch_property_address(
zend_handle_fetch_obj_flags(result, ptr, NULL, prop_info, flags);
}
}
zend_track_property_array_indirect_mutation(ptr, type);
return;
}
} else if (UNEXPECTED(IS_HOOKED_PROPERTY_OFFSET(prop_offset))) {
Expand All @@ -3606,6 +3626,7 @@ static zend_always_inline void zend_fetch_property_address(
ptr = zend_hash_find_known_hash(zobj->properties, Z_STR_P(prop_ptr));
if (EXPECTED(ptr)) {
ZVAL_INDIRECT(result, ptr);
zend_track_property_array_indirect_mutation(ptr, type);
return;
}
}
Expand Down Expand Up @@ -3653,6 +3674,7 @@ static zend_always_inline void zend_fetch_property_address(
}
}
}
zend_track_property_array_indirect_mutation(ptr, type);

end:
if (prop_info_p) {
Expand Down Expand Up @@ -3828,6 +3850,12 @@ static zend_always_inline zval* zend_fetch_static_property_address(zend_property
result = CACHED_PTR(cache_slot + sizeof(void *));
property_info = CACHED_PTR(cache_slot + sizeof(void *) * 2);

if (UNEXPECTED(EG(static_cache_class_access_active) &&
zend_class_static_access_hook != NULL)
) {
zend_class_static_access_hook(property_info->ce);
}

if ((fetch_type == BP_VAR_R || fetch_type == BP_VAR_RW)
&& UNEXPECTED(Z_TYPE_P(result) == IS_UNDEF)
&& ZEND_TYPE_IS_SET(property_info->type)) {
Expand Down Expand Up @@ -4102,6 +4130,20 @@ ZEND_API zval* zend_assign_to_typed_ref(zval *variable_ptr, zval *orig_value, ui
return result;
}

zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_track_object_mutation_slow(zend_object *zobj)
{
if (zobj != NULL && zend_tracked_object_mutation_hook != NULL && EG(exception) == NULL) {
zend_tracked_object_mutation_hook(zobj);
}
}

zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_track_object_mutation_with_value_slow(zend_object *zobj, zval *value)
{
if (zobj != NULL && zend_tracked_object_mutation_hook != NULL && EG(exception) == NULL && value != &EG(error_zval)) {
zend_tracked_object_mutation_hook(zobj);
}
}

ZEND_API bool ZEND_FASTCALL zend_verify_prop_assignable_by_ref_ex(const zend_property_info *prop_info, zval *orig_val, bool strict, zend_verify_prop_assignable_by_ref_context context) {
zval *val = orig_val;
if (Z_ISREF_P(val) && ZEND_REF_HAS_TYPE_SOURCES(Z_REF_P(val))) {
Expand Down
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