Alternative Fiber Internals Refactoring (#7101)

Zend/zend_execute_API.c

@@ -380,6 +380,7 @@ void shutdown_executor(void) /* {{{ */
 	zend_objects_store_free_object_storage(&EG(objects_store), fast_shutdown);
 
 	zend_weakrefs_shutdown();
+	zend_fiber_shutdown();
 
 	zend_try {
 		zend_llist_apply(&zend_extensions, (llist_apply_func_t) zend_extension_deactivator);

Zend/zend_fibers.c

@@ -78,28 +78,6 @@ extern transfer_t jump_fcontext(fcontext_t to, void *vp);
 
 #define ZEND_FIBER_DEFAULT_PAGE_SIZE 4096
 
-#define ZEND_FIBER_BACKUP_EG(stack, stack_page_size, execute_data, error_reporting, trace_num, bailout) do { \
-	stack = EG(vm_stack); \
-	stack->top = EG(vm_stack_top); \
-	stack->end = EG(vm_stack_end); \
-	stack_page_size = EG(vm_stack_page_size); \
-	execute_data = EG(current_execute_data); \
-	error_reporting = EG(error_reporting); \
-	trace_num = EG(jit_trace_num); \
-	bailout = EG(bailout); \
-} while (0)
-
-#define ZEND_FIBER_RESTORE_EG(stack, stack_page_size, execute_data, error_reporting, trace_num, bailout) do { \
-	EG(vm_stack) = stack; \
-	EG(vm_stack_top) = stack->top; \
-	EG(vm_stack_end) = stack->end; \
-	EG(vm_stack_page_size) = stack_page_size; \
-	EG(current_execute_data) = execute_data; \
-	EG(error_reporting) = error_reporting; \
-	EG(jit_trace_num) = trace_num; \
-	EG(bailout) = bailout; \
-} while (0)
-
 static size_t zend_fiber_get_page_size(void)
 {
 	static size_t page_size = 0;
@@ -172,6 +150,11 @@ static bool zend_fiber_stack_allocate(zend_fiber_stack *stack, size_t size)
 	stack->valgrind = VALGRIND_STACK_REGISTER(base, base + stack->size);
 #endif
 
+#ifdef __SANITIZE_ADDRESS__
+	stack->prior_pointer = stack->pointer;
+	stack->prior_size = stack->size;
+#endif
+
 	return true;
 }
 
@@ -200,24 +183,19 @@ static void zend_fiber_stack_free(zend_fiber_stack *stack)
 
 static ZEND_NORETURN void zend_fiber_trampoline(transfer_t transfer)
 {
-	zend_fiber_context *context = transfer.data;
+	zend_fiber_context *context = EG(current_fiber);
+	zend_fiber_context *from = transfer.data;
+
+	from->handle = transfer.context;
 
 #ifdef __SANITIZE_ADDRESS__
-	__sanitizer_finish_switch_fiber(NULL, &context->stack.prior_pointer, &context->stack.prior_size);
+	__sanitizer_finish_switch_fiber(NULL, &from->stack.prior_pointer, &from->stack.prior_size);
 #endif
 
-	context->caller = transfer.context;
+	/* Final context switch, the fiber must not be resumed afterwards! */
-
+	zend_fiber_switch_context(context->function(context));
-	context->function(context);
-
-	context->self = NULL;
-
-#ifdef __SANITIZE_ADDRESS__
-	__sanitizer_start_switch_fiber(NULL, context->stack.prior_pointer, context->stack.prior_size);
-#endif
-
-	jump_fcontext(context->caller, NULL);
 
+	/* Abort here because we are in an inconsistent program state. */
 	abort();
 }
 
@@ -230,10 +208,10 @@ ZEND_API bool zend_fiber_init_context(zend_fiber_context *context, zend_fiber_co
 	// Stack grows down, calculate the top of the stack. make_fcontext then shifts pointer to lower 16-byte boundary.
 	void *stack = (void *) ((uintptr_t) context->stack.pointer + context->stack.size);
 
-	context->self = make_fcontext(stack, context->stack.size, zend_fiber_trampoline);
+	context->handle = make_fcontext(stack, context->stack.size, zend_fiber_trampoline);
-	ZEND_ASSERT(context->self != NULL && "make_fcontext() never returns NULL");
+	ZEND_ASSERT(context->handle != NULL && "make_fcontext() never returns NULL");
+
 	context->function = coroutine;
-	context->caller = NULL;
 
 	return true;
 }
@@ -245,81 +223,59 @@ ZEND_API void zend_fiber_destroy_context(zend_fiber_context *context)
 
 ZEND_API void zend_fiber_switch_context(zend_fiber_context *to)
 {
-	ZEND_ASSERT(to && to->self && to->stack.pointer && "Invalid fiber context");
+	zend_fiber_context *from = EG(current_fiber);
+
+	ZEND_ASSERT(to && to->handle && "Invalid fiber context");
+	ZEND_ASSERT(from && "From fiber context must be present");
+	ZEND_ASSERT(to != from && "Cannot switch into the running fiber context");
 
 #ifdef __SANITIZE_ADDRESS__
-	void *fake_stack;
+	void *fake_stack = NULL;
-	__sanitizer_start_switch_fiber(&fake_stack, to->stack.pointer, to->stack.size);
+	__sanitizer_start_switch_fiber(
+		from->status != ZEND_FIBER_STATUS_DEAD ? &fake_stack : NULL,
+		to->stack.prior_pointer,
+		to->stack.prior_size);
 #endif
 
-	transfer_t transfer = jump_fcontext(to->self, to);
+	EG(current_fiber) = to;
+
+	transfer_t transfer = jump_fcontext(to->handle, from);
+	((zend_fiber_context *) transfer.data)->handle = transfer.context;
+
+	EG(current_fiber) = from;
 
 #ifdef __SANITIZE_ADDRESS__
 	__sanitizer_finish_switch_fiber(fake_stack, &to->stack.prior_pointer, &to->stack.prior_size);
 #endif
-
-	to->self = transfer.context;
-}
-
-ZEND_API void zend_fiber_suspend_context(zend_fiber_context *current)
-{
-	ZEND_ASSERT(current && current->caller && current->stack.pointer && "Invalid fiber context");
-
-#ifdef __SANITIZE_ADDRESS__
-	void *fake_stack;
-	__sanitizer_start_switch_fiber(&fake_stack, current->stack.prior_pointer, current->stack.prior_size);
-#endif
-
-	transfer_t transfer = jump_fcontext(current->caller, NULL);
-
-#ifdef __SANITIZE_ADDRESS__
-	__sanitizer_finish_switch_fiber(fake_stack, &current->stack.prior_pointer, &current->stack.prior_size);
-#endif
-
-	current->caller = transfer.context;
 }
 
 static void zend_fiber_suspend_from(zend_fiber *fiber)
 {
-	zend_vm_stack stack;
+	zend_fiber_vm_state state;
-	size_t stack_page_size;
-	zend_execute_data *execute_data;
-	int error_reporting;
-	uint32_t jit_trace_num;
-	JMP_BUF *bailout;
 
-	ZEND_FIBER_BACKUP_EG(stack, stack_page_size, execute_data, error_reporting, jit_trace_num, bailout);
+	ZEND_ASSERT(fiber->caller && "Fiber has no caller");
 
-	zend_fiber_suspend_context(&fiber->context);
+	zend_fiber_capture_vm_state(&state);
-
+	zend_fiber_switch_context(zend_fiber_get_context(fiber->caller));
-	ZEND_FIBER_RESTORE_EG(stack, stack_page_size, execute_data, error_reporting, jit_trace_num, bailout);
+	zend_fiber_restore_vm_state(&state);
 }
 
 static void zend_fiber_switch_to(zend_fiber *fiber)
 {
-	zend_fiber *previous;
+	zend_fiber_context *context = zend_fiber_get_context(fiber);
-	zend_vm_stack stack;
+	zend_fiber_vm_state state;
-	size_t stack_page_size;
-	zend_execute_data *execute_data;
-	int error_reporting;
-	uint32_t jit_trace_num;
-	JMP_BUF *bailout;
 
-	previous = EG(current_fiber);
+	zend_observer_fiber_switch_notify(EG(current_fiber), context);
 
-	zend_observer_fiber_switch_notify(previous, fiber);
+	fiber->caller = zend_fiber_from_context(EG(current_fiber));
 
-	ZEND_FIBER_BACKUP_EG(stack, stack_page_size, execute_data, error_reporting, jit_trace_num, bailout);
+	zend_fiber_capture_vm_state(&state);
+	zend_fiber_switch_context(context);
+	zend_fiber_restore_vm_state(&state);
 
-	EG(current_fiber) = fiber;
+	fiber->caller = NULL;
 
-	zend_fiber_switch_context(&fiber->context);
+	zend_observer_fiber_switch_notify(context, EG(current_fiber));
-
-	EG(current_fiber) = previous;
-
-	ZEND_FIBER_RESTORE_EG(stack, stack_page_size, execute_data, error_reporting, jit_trace_num, bailout);
-
-	zend_observer_fiber_switch_notify(fiber, previous);
 
 	if (UNEXPECTED(fiber->flags & ZEND_FIBER_FLAG_BAILOUT)) {
 		// zend_bailout() was called in the fiber, so call it again in the previous fiber or {main}.
@@ -339,10 +295,9 @@ static zend_always_inline zend_vm_stack zend_fiber_vm_stack_alloc(size_t size)
 	return page;
 }
 
-static void ZEND_STACK_ALIGNED zend_fiber_execute(zend_fiber_context *context)
+static ZEND_STACK_ALIGNED zend_fiber_context *zend_fiber_execute(zend_fiber_context *context)
 {
-	zend_fiber *fiber = EG(current_fiber);
+	zend_fiber *fiber = zend_fiber_from_context(context);
-	ZEND_ASSERT(fiber);
 
 	zend_long error_reporting = INI_INT("error_reporting");
 	if (!error_reporting && !INI_STR("error_reporting")) {
@@ -396,6 +351,8 @@ static void ZEND_STACK_ALIGNED zend_fiber_execute(zend_fiber_context *context)
 	zend_vm_stack_destroy();
 	fiber->execute_data = NULL;
 	fiber->stack_bottom = NULL;
+
+	return zend_fiber_get_context(fiber->caller);
 }
 
 static zend_object *zend_fiber_object_create(zend_class_entry *ce)
@@ -454,7 +411,7 @@ static void zend_fiber_object_free(zend_object *object)
 
 	zval_ptr_dtor(&fiber->value);
 
-	zend_fiber_destroy_context(&fiber->context);
+	zend_fiber_destroy_context(zend_fiber_get_context(fiber));
 
 	zend_object_std_dtor(&fiber->std);
 }
@@ -494,7 +451,7 @@ ZEND_API void zend_fiber_start(zend_fiber *fiber, zval *params, uint32_t param_c
 	fiber->fci.param_count = param_count;
 	fiber->fci.named_params = named_params;
 
-	if (!zend_fiber_init_context(&fiber->context, zend_fiber_execute, EG(fiber_stack_size))) {
+	if (!zend_fiber_init_context(zend_fiber_get_context(fiber), zend_fiber_execute, EG(fiber_stack_size))) {
 		RETURN_THROWS();
 	}
 
@@ -524,13 +481,13 @@ ZEND_METHOD(Fiber, start)
 
 ZEND_API void zend_fiber_suspend(zval *value, zval *return_value)
 {
-	zend_fiber *fiber = EG(current_fiber);
+	if (UNEXPECTED(EG(current_fiber) == EG(main_fiber))) {
-
-	if (UNEXPECTED(!fiber)) {
 		zend_throw_error(zend_ce_fiber_error, "Cannot suspend outside of a fiber");
 		RETURN_THROWS();
 	}
 
+	zend_fiber *fiber = zend_fiber_from_context(EG(current_fiber));
+
 	if (UNEXPECTED(fiber->flags & ZEND_FIBER_FLAG_DESTROYED)) {
 		zend_throw_error(zend_ce_fiber_error, "Cannot suspend in a force-closed fiber");
 		RETURN_THROWS();
@@ -734,17 +691,13 @@ ZEND_METHOD(Fiber, getReturn)
 
 ZEND_METHOD(Fiber, this)
 {
-	zend_fiber *fiber;
-
 	ZEND_PARSE_PARAMETERS_NONE();
 
-	fiber = EG(current_fiber);
+	if (EG(current_fiber) == EG(main_fiber)) {
-
-	if (!fiber) {
 		RETURN_NULL();
 	}
 
-	RETURN_OBJ_COPY(&fiber->std);
+	RETURN_OBJ_COPY(&zend_fiber_from_context(EG(current_fiber))->std);
 }
 
 ZEND_METHOD(FiberError, __construct)
@@ -775,5 +728,15 @@ void zend_register_fiber_ce(void)
 
 void zend_fiber_init(void)
 {
-	EG(current_fiber) = NULL;
+	zend_fiber_context *context = ecalloc(1, sizeof(zend_fiber_context));
+
+	context->status = ZEND_FIBER_STATUS_RUNNING;
+
+	EG(main_fiber) = context;
+	EG(current_fiber) = context;
+}
+
+void zend_fiber_shutdown(void)
+{
+	efree(EG(main_fiber));
 }

Zend/zend_fibers.h

@@ -23,6 +23,11 @@
 #include "zend_API.h"
 #include "zend_types.h"
 
+#define ZEND_FIBER_GUARD_PAGES 1
+
+#define ZEND_FIBER_DEFAULT_C_STACK_SIZE (4096 * (((sizeof(void *)) < 8) ? 256 : 512))
+#define ZEND_FIBER_VM_STACK_SIZE (1024 * sizeof(zval))
+
 BEGIN_EXTERN_C()
 
 typedef enum {
@@ -40,13 +45,11 @@ typedef enum {
 
 void zend_register_fiber_ce(void);
 void zend_fiber_init(void);
+void zend_fiber_shutdown(void);
 
 extern ZEND_API zend_class_entry *zend_ce_fiber;
 
-typedef struct _zend_fiber_context zend_fiber_context;
+/* Encapsulates the fiber C stack with extension for debugging tools. */
-
-typedef void (*zend_fiber_coroutine)(zend_fiber_context *context);
-
 typedef struct _zend_fiber_stack {
 	void *pointer;
 	size_t size;
@@ -61,30 +64,49 @@ typedef struct _zend_fiber_stack {
 #endif
 } zend_fiber_stack;
 
-typedef struct _zend_fiber_context {
+typedef struct _zend_fiber zend_fiber;
-	void *self;
+typedef struct _zend_fiber_context zend_fiber_context;
-	void *caller;
-	zend_fiber_coroutine function;
-	zend_fiber_stack stack;
-} zend_fiber_context;
 
-typedef struct _zend_fiber {
+/* Coroutine functions must return a fiber context to switch to after they are finished. */
-	/* Fiber PHP object handle. */
+typedef zend_fiber_context *(*zend_fiber_coroutine)(zend_fiber_context *context);
+
+/* Defined as a macro to allow anonymous embedding. */
+#define ZEND_FIBER_CONTEXT_FIELDS \
+	void *handle; \
+	zend_fiber_coroutine function; \
+	zend_fiber_stack stack; \
+	zend_fiber_status status; \
+	zend_uchar flags
+
+/* Standalone context (used primarily as pointer type). */
+struct _zend_fiber_context {
+	ZEND_FIBER_CONTEXT_FIELDS;
+};
+
+/* Zend VM state that needs to be captured / restored during fiber context switch. */
+typedef struct _zend_fiber_vm_state {
+	zend_vm_stack vm_stack;
+	size_t vm_stack_page_size;
+	zend_execute_data *current_execute_data;
+	int error_reporting;
+	uint32_t jit_trace_num;
+	JMP_BUF *bailout;
+} zend_fiber_vm_state;
+
+struct _zend_fiber {
+	/* PHP object handle. */
 	zend_object std;
 
-	/* Status of the fiber, one of the zend_fiber_status values. */
+	/* Fiber that resumed us. */
-	zend_fiber_status status;
+	zend_fiber *caller;
 
-	/* Flags of the fiber, bit field of the zend_fiber_flag values. */
+	/* Fiber context fields (embedded to avoid memory allocation). */
-	zend_uchar flags;
+	ZEND_FIBER_CONTEXT_FIELDS;
 
 	/* Callback and info / cache to be used when fiber is started. */
 	zend_fcall_info fci;
 	zend_fcall_info_cache fci_cache;
 
-	/* Context of this fiber, will be initialized during call to Fiber::start(). */
-	zend_fiber_context context;
-
 	/* Current Zend VM execute data being run by the fiber. */
 	zend_execute_data *execute_data;
 
@@ -96,7 +118,7 @@ typedef struct _zend_fiber {
 
 	/* Storage for temporaries and fiber return value. */
 	zval value;
-} zend_fiber;
+};
 
 /* These functions create and manipulate a Fiber object, allowing any internal function to start, resume, or suspend a fiber. */
 ZEND_API zend_fiber *zend_fiber_create(const zend_fcall_info *fci, const zend_fcall_info_cache *fci_cache);
@@ -109,14 +131,41 @@ ZEND_API void zend_fiber_throw(zend_fiber *fiber, zval *exception, zval *return_
 ZEND_API zend_bool zend_fiber_init_context(zend_fiber_context *context, zend_fiber_coroutine coroutine, size_t stack_size);
 ZEND_API void zend_fiber_destroy_context(zend_fiber_context *context);
 ZEND_API void zend_fiber_switch_context(zend_fiber_context *to);
-ZEND_API void zend_fiber_suspend_context(zend_fiber_context *current);
-
-#define ZEND_FIBER_GUARD_PAGES 1
-
-#define ZEND_FIBER_DEFAULT_C_STACK_SIZE (4096 * (((sizeof(void *)) < 8) ? 256 : 512))
-
-#define ZEND_FIBER_VM_STACK_SIZE (1024 * sizeof(zval))
 
 END_EXTERN_C()
 
+static zend_always_inline zend_fiber *zend_fiber_from_context(zend_fiber_context *context)
+{
+	return (zend_fiber *)(((char *) context) - XtOffsetOf(zend_fiber, handle));
+}
+
+static zend_always_inline zend_fiber_context *zend_fiber_get_context(zend_fiber *fiber)
+{
+	return (zend_fiber_context *) &fiber->handle;
+}
+
+static zend_always_inline void zend_fiber_capture_vm_state(zend_fiber_vm_state *state)
+{
+	state->vm_stack = EG(vm_stack);
+	state->vm_stack->top = EG(vm_stack_top);
+	state->vm_stack->end = EG(vm_stack_end);
+	state->vm_stack_page_size = EG(vm_stack_page_size);
+	state->current_execute_data = EG(current_execute_data);
+	state->error_reporting = EG(error_reporting);
+	state->jit_trace_num = EG(jit_trace_num);
+	state->bailout = EG(bailout);
+}
+
+static zend_always_inline void zend_fiber_restore_vm_state(zend_fiber_vm_state *state)
+{
+	EG(vm_stack) = state->vm_stack;
+	EG(vm_stack_top) = state->vm_stack->top;
+	EG(vm_stack_end) = state->vm_stack->end;
+	EG(vm_stack_page_size) = state->vm_stack_page_size;
+	EG(current_execute_data) = state->current_execute_data;
+	EG(error_reporting) = state->error_reporting;
+	EG(jit_trace_num) = state->jit_trace_num;
+	EG(bailout) = state->bailout;
+}
+
 #endif

Zend/zend_globals.h

@@ -61,8 +61,7 @@ END_EXTERN_C()
 
 typedef struct _zend_vm_stack *zend_vm_stack;
 typedef struct _zend_ini_entry zend_ini_entry;
-typedef struct _zend_fiber zend_fiber;
+typedef struct _zend_fiber_context zend_fiber_context;
-
 
 struct _zend_compiler_globals {
 	zend_stack loop_var_stack;
@@ -250,8 +249,8 @@ struct _zend_executor_globals {
 
 	zend_get_gc_buffer get_gc_buffer;
 
-	/* Active fiber, NULL when in main thread. */
+	zend_fiber_context *main_fiber;
-	zend_fiber *current_fiber;
+	zend_fiber_context *current_fiber;
 
 	/* Default fiber C stack size. */
 	zend_long fiber_stack_size;

Zend/zend_observer.c

@@ -264,7 +264,7 @@ ZEND_API void zend_observer_fiber_switch_register(zend_observer_fiber_switch_han
 	zend_llist_add_element(&zend_observer_fiber_switch, &handler);
 }
 
-void zend_observer_fiber_switch_notify(zend_fiber *from, zend_fiber *to)
+ZEND_API void ZEND_FASTCALL zend_observer_fiber_switch_notify(zend_fiber_context *from, zend_fiber_context *to)
 {
 	zend_llist_element *element;
 	zend_observer_fiber_switch_handler callback;

Zend/zend_observer.h

@@ -78,10 +78,10 @@ typedef void (*zend_observer_error_cb)(int type, zend_string *error_filename, ui
 ZEND_API void zend_observer_error_register(zend_observer_error_cb callback);
 void zend_observer_error_notify(int type, zend_string *error_filename, uint32_t error_lineno, zend_string *message);
 
-typedef void (*zend_observer_fiber_switch_handler)(zend_fiber *from, zend_fiber *to);
+typedef void (*zend_observer_fiber_switch_handler)(zend_fiber_context *from, zend_fiber_context *to);
 
 ZEND_API void zend_observer_fiber_switch_register(zend_observer_fiber_switch_handler handler);
-void zend_observer_fiber_switch_notify(zend_fiber *from, zend_fiber *to);
+ZEND_API void ZEND_FASTCALL zend_observer_fiber_switch_notify(zend_fiber_context *from, zend_fiber_context *to);
 
 END_EXTERN_C()
 

ext/reflection/php_reflection.c

@@ -6895,7 +6895,7 @@ ZEND_METHOD(ReflectionFiber, getTrace)
 	prev_execute_data = fiber->stack_bottom->prev_execute_data;
 	fiber->stack_bottom->prev_execute_data = NULL;
 
-	if (EG(current_fiber) != fiber) {
+	if (EG(current_fiber) != zend_fiber_get_context(fiber)) {
 		// No need to replace current execute data if within the current fiber.
 		EG(current_execute_data) = fiber->execute_data;
 	}
@@ -6915,7 +6915,7 @@ ZEND_METHOD(ReflectionFiber, getExecutingLine)
 
 	REFLECTION_CHECK_VALID_FIBER(fiber);
 
-	if (EG(current_fiber) == fiber) {
+	if (EG(current_fiber) == zend_fiber_get_context(fiber)) {
 		prev_execute_data = execute_data->prev_execute_data;
 	} else {
 		prev_execute_data = fiber->execute_data->prev_execute_data;
@@ -6933,7 +6933,7 @@ ZEND_METHOD(ReflectionFiber, getExecutingFile)
 
 	REFLECTION_CHECK_VALID_FIBER(fiber);
 
-	if (EG(current_fiber) == fiber) {
+	if (EG(current_fiber) == zend_fiber_get_context(fiber)) {
 		prev_execute_data = execute_data->prev_execute_data;
 	} else {
 		prev_execute_data = fiber->execute_data->prev_execute_data;

ext/zend_test/test.c

@@ -411,44 +411,40 @@ static void observer_set_user_opcode_handler(const char *opcode_names, user_opco
 	}
 }
 
-static void fiber_address_observer(zend_fiber *from, zend_fiber *to)
+static void fiber_address_observer(zend_fiber_context *from, zend_fiber_context *to)
 {
 	if (ZT_G(observer_fiber_switch)) {
 		php_printf("<!-- switching from fiber %p to %p -->\n", from, to);
 	}
 }
 
-static void fiber_enter_observer(zend_fiber *from, zend_fiber *to)
+static void fiber_enter_observer(zend_fiber_context *from, zend_fiber_context *to)
 {
 	if (ZT_G(observer_fiber_switch)) {
-		if (to) {
+		if (to->status == ZEND_FIBER_STATUS_INIT) {
-			if (to->status == ZEND_FIBER_STATUS_INIT) {
+			php_printf("<init '%p'>\n", to);
-				php_printf("<init '%p'>\n", to);
+		} else if (to->status == ZEND_FIBER_STATUS_RUNNING && from->status == ZEND_FIBER_STATUS_RUNNING) {
-			} else if (to->status == ZEND_FIBER_STATUS_RUNNING && (!from || from->status == ZEND_FIBER_STATUS_RUNNING)) {
+			if (to->flags & ZEND_FIBER_FLAG_DESTROYED) {
-				if (to->flags & ZEND_FIBER_FLAG_DESTROYED) {
+				php_printf("<destroying '%p'>\n", to);
-					php_printf("<destroying '%p'>\n", to);
+			} else if (to->status != ZEND_FIBER_STATUS_DEAD) {
-				} else if (to->status != ZEND_FIBER_STATUS_DEAD) {
+				php_printf("<resume '%p'>\n", to);
-					php_printf("<resume '%p'>\n", to);
-				}
 			}
 		}
 	}
 }
 
-static void fiber_suspend_observer(zend_fiber *from, zend_fiber *to)
+static void fiber_suspend_observer(zend_fiber_context *from, zend_fiber_context *to)
 {
 	if (ZT_G(observer_fiber_switch)) {
-		if (from) {
+		if (from->status == ZEND_FIBER_STATUS_SUSPENDED) {
-			if (from->status == ZEND_FIBER_STATUS_SUSPENDED) {
+			php_printf("<suspend '%p'>\n", from);
-				php_printf("<suspend '%p'>\n", from);
+		} else if (from->status == ZEND_FIBER_STATUS_DEAD) {
-			} else if (from->status == ZEND_FIBER_STATUS_DEAD) {
+			if (from->flags & ZEND_FIBER_FLAG_THREW) {
-				if (from->flags & ZEND_FIBER_FLAG_THREW) {
+				php_printf("<threw '%p'>\n", from);
-					php_printf("<threw '%p'>\n", from);
+			} else if (from->flags & ZEND_FIBER_FLAG_DESTROYED) {
-				} else if (from->flags & ZEND_FIBER_FLAG_DESTROYED) {
+				php_printf("<destroyed '%p'>\n", from);
-					php_printf("<destroyed '%p'>\n", from);
+			} else {
-				} else {
+				php_printf("<returned '%p'>\n", from);
-					php_printf("<returned '%p'>\n", from);
-				}
 			}
 		}
 	}

ext/zend_test/tests/observer_fiber_01.phpt

@@ -18,12 +18,12 @@ $fiber->resume();
 ?>
 --EXPECTF--
 <!-- init '%sobserver_fiber_01.php' -->
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <init '%s'>
 <!-- init {closure}() -->
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <resume '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <returned '%s'>

ext/zend_test/tests/observer_fiber_02.phpt

@@ -17,12 +17,12 @@ $fiber->start();
 ?>
 --EXPECTF--
 <!-- init '%sobserver_fiber_02.php' -->
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <init '%s'>
 <!-- init {closure}() -->
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <destroying '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <destroyed '%s'>

ext/zend_test/tests/observer_fiber_03.phpt

@@ -40,12 +40,12 @@ $fiber->resume();
 ?>
 --EXPECTF--
 <!-- init '%sobserver_fiber_03.php' -->
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <init '%s'>
 <!-- init {closure}() -->
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <resume '%s'>
 int(1)
 <!-- switching from fiber %s to %s -->
@@ -53,9 +53,9 @@ int(1)
 <!-- init {closure}() -->
 <!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <resume '%s'>
 int(2)
 <!-- switching from fiber %s to %s -->
@@ -63,9 +63,9 @@ int(2)
 int(3)
 <!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <resume '%s'>
 int(4)
 <!-- switching from fiber %s to %s -->
@@ -73,5 +73,5 @@ int(4)
 int(5)
 <!-- switching from fiber %s to %s -->
 <returned '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <returned '%s'>

ext/zend_test/tests/observer_fiber_04.phpt

@@ -27,25 +27,25 @@ $fiber->resume();
 ?>
 --EXPECTF--
 <!-- init '%sobserver_fiber_04.php' -->
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <init '%s'>
 <!-- init {closure}() -->
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <resume '%s'>
 <!-- switching from fiber %s to %s -->
 <init '%s'>
 <!-- init {closure}() -->
 <!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <resume '%s'>
 <!-- switching from fiber %s to %s -->
 <destroying '%s'>
 <!-- switching from fiber %s to %s -->
 <destroyed '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <returned '%s'>

ext/zend_test/tests/observer_fiber_05.phpt

@@ -26,25 +26,25 @@ $fiber->resume();
 ?>
 --EXPECTF--
 <!-- init '%sobserver_fiber_05.php' -->
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <init '%s'>
 <!-- init {closure}() -->
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <resume '%s'>
 <!-- switching from fiber %s to %s -->
 <init '%s'>
 <!-- init {closure}() -->
 <!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <destroying '%s'>
 <!-- switching from fiber %s to %s -->
 <destroying '%s'>
 <!-- switching from fiber %s to %s -->
 <destroyed '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <destroyed '%s'>

ext/zend_test/tests/observer_fiber_06.phpt

@@ -23,12 +23,12 @@ try {
 ?>
 --EXPECTF--
 <!-- init '%sobserver_fiber_06.php' -->
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <init '%s'>
 <!-- init {closure}() -->
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <suspend '%s'>
-<!-- switching from fiber 0 to %s -->
+<!-- switching from fiber %s to %s -->
 <resume '%s'>
-<!-- switching from fiber %s to 0 -->
+<!-- switching from fiber %s to %s -->
 <threw '%s'>