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Merged
merged 1 commit into from
Jun 18, 2021
Merged

Flexible fiber bailout handling #7163

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30 changes: 16 additions & 14 deletions Zend/zend_fibers.c
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Original file line number Diff line number Diff line change
Expand Up @@ -304,7 +304,7 @@ ZEND_API void zend_fiber_switch_context(zend_fiber_transfer *transfer)

to->status = ZEND_FIBER_STATUS_RUNNING;

if (from->status == ZEND_FIBER_STATUS_RUNNING) {
if (EXPECTED(from->status == ZEND_FIBER_STATUS_RUNNING)) {
from->status = ZEND_FIBER_STATUS_SUSPENDED;
}

Expand Down Expand Up @@ -342,11 +342,6 @@ ZEND_API void zend_fiber_switch_context(zend_fiber_transfer *transfer)
if (to->status == ZEND_FIBER_STATUS_DEAD) {
zend_fiber_destroy_context(to);
}

/* Propagate bailout to current fiber / main. */
if (UNEXPECTED(to->flags & ZEND_FIBER_FLAG_BAILOUT)) {
zend_bailout();
}
}

static ZEND_STACK_ALIGNED void zend_fiber_execute(zend_fiber_transfer *transfer)
Expand All @@ -361,6 +356,7 @@ static ZEND_STACK_ALIGNED void zend_fiber_execute(zend_fiber_transfer *transfer)
}

EG(vm_stack) = NULL;
transfer->flags = 0;

zend_first_try {
zend_vm_stack stack = zend_vm_stack_new_page(ZEND_FIBER_VM_STACK_SIZE, NULL);
Expand Down Expand Up @@ -388,10 +384,10 @@ static ZEND_STACK_ALIGNED void zend_fiber_execute(zend_fiber_transfer *transfer)
zval_ptr_dtor(&fiber->fci.function_name);

if (EG(exception)) {
if (!(fiber->context.flags & ZEND_FIBER_FLAG_DESTROYED)
if (!(fiber->flags & ZEND_FIBER_FLAG_DESTROYED)
|| !(zend_is_graceful_exit(EG(exception)) || zend_is_unwind_exit(EG(exception)))
) {
fiber->context.flags |= ZEND_FIBER_FLAG_THREW;
fiber->flags |= ZEND_FIBER_FLAG_THREW;
transfer->flags = ZEND_FIBER_TRANSFER_FLAG_ERROR;

ZVAL_OBJ_COPY(&transfer->value, EG(exception));
Expand All @@ -402,7 +398,8 @@ static ZEND_STACK_ALIGNED void zend_fiber_execute(zend_fiber_transfer *transfer)
ZVAL_COPY(&transfer->value, &fiber->result);
}
} zend_catch {
fiber->context.flags |= ZEND_FIBER_FLAG_BAILOUT;
fiber->flags |= ZEND_FIBER_FLAG_BAILOUT;
transfer->flags = ZEND_FIBER_TRANSFER_FLAG_BAILOUT;
} zend_end_try();

transfer->context = fiber->caller;
Expand Down Expand Up @@ -447,6 +444,11 @@ static zend_always_inline zend_fiber_transfer zend_fiber_switch_to(

zend_fiber_switch_context(&transfer);

/* Forward bailout into current fiber. */
if (UNEXPECTED(transfer.flags & ZEND_FIBER_TRANSFER_FLAG_BAILOUT)) {
zend_bailout();
}

return transfer;
}

Expand Down Expand Up @@ -499,7 +501,7 @@ static void zend_fiber_object_destroy(zend_object *object)
zend_object *exception = EG(exception);
EG(exception) = NULL;

fiber->context.flags |= ZEND_FIBER_FLAG_DESTROYED;
fiber->flags |= ZEND_FIBER_FLAG_DESTROYED;

zend_fiber_transfer transfer = zend_fiber_resume(fiber, NULL, false);

Expand Down Expand Up @@ -600,7 +602,7 @@ ZEND_METHOD(Fiber, suspend)
RETURN_THROWS();
}

if (UNEXPECTED(fiber->context.flags & ZEND_FIBER_FLAG_DESTROYED)) {
if (UNEXPECTED(fiber->flags & ZEND_FIBER_FLAG_DESTROYED)) {
zend_throw_error(zend_ce_fiber_error, "Cannot suspend in a force-closed fiber");
RETURN_THROWS();
}
Expand All @@ -617,7 +619,7 @@ ZEND_METHOD(Fiber, suspend)

zend_fiber_transfer transfer = zend_fiber_suspend(fiber, value);

if (fiber->context.flags & ZEND_FIBER_FLAG_DESTROYED) {
if (fiber->flags & ZEND_FIBER_FLAG_DESTROYED) {
// This occurs when the fiber is GC'ed while suspended.
zval_ptr_dtor(&transfer.value);
zend_throw_graceful_exit();
Expand Down Expand Up @@ -738,9 +740,9 @@ ZEND_METHOD(Fiber, getReturn)
fiber = (zend_fiber *) Z_OBJ_P(getThis());

if (fiber->context.status == ZEND_FIBER_STATUS_DEAD) {
if (fiber->context.flags & ZEND_FIBER_FLAG_THREW) {
if (fiber->flags & ZEND_FIBER_FLAG_THREW) {
message = "The fiber threw an exception";
} else if (fiber->context.flags & ZEND_FIBER_FLAG_BAILOUT) {
} else if (fiber->flags & ZEND_FIBER_FLAG_BAILOUT) {
message = "The fiber exited with a fatal error";
} else {
RETURN_COPY(&fiber->result);
Expand Down
15 changes: 14 additions & 1 deletion Zend/zend_fibers.h
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,7 @@ typedef enum {

typedef enum {
ZEND_FIBER_TRANSFER_FLAG_ERROR = 1 << 0,
ZEND_FIBER_TRANSFER_FLAG_BAILOUT = 1 << 1
} zend_fiber_transfer_flag;

void zend_register_fiber_ce(void);
Expand All @@ -61,8 +62,10 @@ typedef struct _zend_fiber_stack zend_fiber_stack;
typedef struct _zend_fiber_transfer {
/* Fiber that will be switched to / has resumed us. */
zend_fiber_context *context;

/* Value to that should be send to (or was received from) a fiber. */
zval value;

/* Bitmask of flags defined in enum zend_fiber_transfer_flag. */
uint8_t flags;
} zend_fiber_transfer;
Expand All @@ -74,12 +77,18 @@ typedef void (*zend_fiber_coroutine)(zend_fiber_transfer *transfer);
struct _zend_fiber_context {
/* Handle to fiber state as needed by boost.context */
void *handle;

/* Pointer that identifies the fiber type. */
void *kind;

/* Entrypoint function of the fiber. */
zend_fiber_coroutine function;

/* Assigned C stack. */
zend_fiber_stack *stack;

/* Fiber status. */
zend_fiber_status status;
uint8_t flags;
};

/* Zend VM state that needs to be captured / restored during fiber context switch. */
Expand All @@ -99,6 +108,10 @@ struct _zend_fiber {
/* PHP object handle. */
zend_object std;

/* Flags are defined in enum zend_fiber_flag. */
uint8_t flags;

/* Native C fiber context. */
zend_fiber_context context;

/* Fiber that resumed us. */
Expand Down
17 changes: 12 additions & 5 deletions ext/zend_test/fiber.c
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,11 @@ static zend_fiber_transfer zend_test_fiber_switch_to(zend_fiber_context *context

zend_fiber_switch_context(&transfer);

/* Forward bailout into current fiber. */
if (UNEXPECTED(transfer.flags & ZEND_FIBER_TRANSFER_FLAG_BAILOUT)) {
zend_bailout();
}

return transfer;
}

Expand Down Expand Up @@ -74,6 +79,7 @@ static ZEND_STACK_ALIGNED void zend_test_fiber_execute(zend_fiber_transfer *tran
zend_execute_data *execute_data;

EG(vm_stack) = NULL;
transfer->flags = 0;

zend_first_try {
zend_vm_stack stack = zend_vm_stack_new_page(ZEND_FIBER_VM_STACK_SIZE, NULL);
Expand All @@ -97,10 +103,10 @@ static ZEND_STACK_ALIGNED void zend_test_fiber_execute(zend_fiber_transfer *tran
zval_ptr_dtor(&fiber->fci.function_name);

if (EG(exception)) {
if (!(fiber->context.flags & ZEND_FIBER_FLAG_DESTROYED)
if (!(fiber->flags & ZEND_FIBER_FLAG_DESTROYED)
|| !(zend_is_graceful_exit(EG(exception)) || zend_is_unwind_exit(EG(exception)))
) {
fiber->context.flags |= ZEND_FIBER_FLAG_THREW;
fiber->flags |= ZEND_FIBER_FLAG_THREW;
transfer->flags = ZEND_FIBER_TRANSFER_FLAG_ERROR;

ZVAL_OBJ_COPY(&transfer->value, EG(exception));
Expand All @@ -112,7 +118,8 @@ static ZEND_STACK_ALIGNED void zend_test_fiber_execute(zend_fiber_transfer *tran
ZVAL_COPY(&transfer->value, &fiber->result);
}
} zend_catch {
fiber->context.flags |= ZEND_FIBER_FLAG_BAILOUT;
fiber->flags |= ZEND_FIBER_FLAG_BAILOUT;
transfer->flags = ZEND_FIBER_TRANSFER_FLAG_BAILOUT;
} zend_end_try();

zend_vm_stack_destroy();
Expand Down Expand Up @@ -159,7 +166,7 @@ static void zend_test_fiber_object_destroy(zend_object *object)
zend_object *exception = EG(exception);
EG(exception) = NULL;

fiber->context.flags |= ZEND_FIBER_FLAG_DESTROYED;
fiber->flags |= ZEND_FIBER_FLAG_DESTROYED;

zend_fiber_transfer transfer = zend_test_fiber_resume(fiber, NULL, false);

Expand Down Expand Up @@ -274,7 +281,7 @@ static ZEND_METHOD(_ZendTestFiber, suspend)

zend_fiber_transfer transfer = zend_test_fiber_suspend(fiber, value);

if (fiber->context.flags & ZEND_FIBER_FLAG_DESTROYED) {
if (fiber->flags & ZEND_FIBER_FLAG_DESTROYED) {
// This occurs when the test fiber is GC'ed while suspended.
zval_ptr_dtor(&transfer.value);
zend_throw_graceful_exit();
Expand Down
1 change: 1 addition & 0 deletions ext/zend_test/fiber.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ typedef struct _zend_test_fiber zend_test_fiber;

struct _zend_test_fiber {
zend_object std;
uint8_t flags;
zend_fiber_context context;
zend_fiber_context *caller;
zend_fiber_context *previous;
Expand Down
8 changes: 5 additions & 3 deletions ext/zend_test/observer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -207,7 +207,7 @@ static void fiber_enter_observer(zend_fiber_context *from, zend_fiber_context *t
return;
}

if (to->flags & ZEND_FIBER_FLAG_DESTROYED) {
if (fiber->flags & ZEND_FIBER_FLAG_DESTROYED) {
php_printf("<destroying '%p'>\n", to);
} else if (to->status != ZEND_FIBER_STATUS_DEAD) {
php_printf("<resume '%p'>\n", to);
Expand All @@ -220,9 +220,11 @@ static void fiber_suspend_observer(zend_fiber_context *from, zend_fiber_context
{
if (ZT_G(observer_fiber_switch)) {
if (from->status == ZEND_FIBER_STATUS_DEAD) {
if (from->flags & ZEND_FIBER_FLAG_THREW) {
zend_fiber *fiber = (from->kind == zend_ce_fiber) ? zend_fiber_from_context(from) : NULL;

if (fiber && fiber->flags & ZEND_FIBER_FLAG_THREW) {
php_printf("<threw '%p'>\n", from);
} else if (from->flags & ZEND_FIBER_FLAG_DESTROYED) {
} else if (fiber && fiber->flags & ZEND_FIBER_FLAG_DESTROYED) {
php_printf("<destroyed '%p'>\n", from);
} else {
php_printf("<returned '%p'>\n", from);
Expand Down