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duktape/src-input/duk_js_call.c

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/*
* Call handling.
*
* Main functions are:
*
* - duk_handle_call_unprotected(): unprotected call to Ecmascript or
* Duktape/C function
* - duk_handle_call_protected(): protected call to Ecmascript or
* Duktape/C function
* - duk_handle_safe_call(): make a protected C call within current
* activation
* - duk_handle_ecma_call_setup(): Ecmascript-to-Ecmascript calls
* (not always possible), including tail calls and coroutine resume
*
* See 'execution.rst'.
*
* Note: setjmp() and local variables have a nasty interaction,
* see execution.rst; non-volatile locals modified after setjmp()
* call are not guaranteed to keep their value.
*/
#include "duk_internal.h"
/*
* Forward declarations.
*/
DUK_LOCAL void duk__handle_call_inner(duk_hthread *thr,
duk_idx_t num_stack_args,
duk_small_uint_t call_flags,
duk_idx_t idx_func);
DUK_LOCAL void duk__handle_call_error(duk_hthread *thr,
duk_size_t entry_valstack_bottom_index,
duk_size_t entry_valstack_end,
duk_size_t entry_catchstack_top,
duk_size_t entry_callstack_top,
duk_int_t entry_call_recursion_depth,
duk_hthread *entry_curr_thread,
duk_uint_fast8_t entry_thread_state,
duk_instr_t **entry_ptr_curr_pc,
duk_idx_t idx_func,
duk_jmpbuf *old_jmpbuf_ptr);
DUK_LOCAL void duk__handle_safe_call_inner(duk_hthread *thr,
duk_safe_call_function func,
void *udata,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets,
duk_size_t entry_valstack_bottom_index,
duk_size_t entry_callstack_top,
duk_size_t entry_catchstack_top);
DUK_LOCAL void duk__handle_safe_call_error(duk_hthread *thr,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets,
duk_size_t entry_valstack_bottom_index,
duk_size_t entry_callstack_top,
duk_size_t entry_catchstack_top,
duk_jmpbuf *old_jmpbuf_ptr);
DUK_LOCAL void duk__handle_safe_call_shared(duk_hthread *thr,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets,
duk_int_t entry_call_recursion_depth,
duk_hthread *entry_curr_thread,
duk_uint_fast8_t entry_thread_state,
duk_instr_t **entry_ptr_curr_pc);
/*
* Interrupt counter fixup (for development only).
*/
#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
DUK_LOCAL void duk__interrupt_fixup(duk_hthread *thr, duk_hthread *entry_curr_thread) {
/* Currently the bytecode executor and executor interrupt
* instruction counts are off because we don't execute the
* interrupt handler when we're about to exit from the initial
* user call into Duktape.
*
* If we were to execute the interrupt handler here, the counts
* would match. You can enable this block manually to check
* that this is the case.
*/
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr->heap != NULL);
#if defined(DUK_USE_INTERRUPT_DEBUG_FIXUP)
if (entry_curr_thread == NULL) {
thr->interrupt_init = thr->interrupt_init - thr->interrupt_counter;
thr->heap->inst_count_interrupt += thr->interrupt_init;
DUK_DD(DUK_DDPRINT("debug test: updated interrupt count on exit to "
"user code, instruction counts: executor=%ld, interrupt=%ld",
(long) thr->heap->inst_count_exec, (long) thr->heap->inst_count_interrupt));
DUK_ASSERT(thr->heap->inst_count_exec == thr->heap->inst_count_interrupt);
}
#else
DUK_UNREF(thr);
DUK_UNREF(entry_curr_thread);
#endif
}
#endif
/*
* Arguments object creation.
*
* Creating arguments objects involves many small details, see E5 Section
* 10.6 for the specific requirements. Much of the arguments object exotic
* behavior is implemented in duk_hobject_props.c, and is enabled by the
* object flag DUK_HOBJECT_FLAG_EXOTIC_ARGUMENTS.
*/
DUK_LOCAL void duk__create_arguments_object(duk_hthread *thr,
duk_hobject *func,
duk_hobject *varenv,
duk_idx_t idx_argbase, /* idx of first argument on stack */
duk_idx_t num_stack_args) { /* num args starting from idx_argbase */
duk_context *ctx = (duk_context *) thr;
duk_hobject *arg; /* 'arguments' */
duk_hobject *formals; /* formals for 'func' (may be NULL if func is a C function) */
duk_idx_t i_arg;
duk_idx_t i_map;
duk_idx_t i_mappednames;
duk_idx_t i_formals;
duk_idx_t i_argbase;
duk_idx_t n_formals;
duk_idx_t idx;
duk_bool_t need_map;
DUK_DDD(DUK_DDDPRINT("creating arguments object for func=%!iO, varenv=%!iO, "
"idx_argbase=%ld, num_stack_args=%ld",
(duk_heaphdr *) func, (duk_heaphdr *) varenv,
(long) idx_argbase, (long) num_stack_args));
DUK_ASSERT(thr != NULL);
DUK_ASSERT(func != NULL);
DUK_ASSERT(DUK_HOBJECT_IS_NONBOUND_FUNCTION(func));
DUK_ASSERT(varenv != NULL);
DUK_ASSERT(idx_argbase >= 0); /* assumed to bottom relative */
DUK_ASSERT(num_stack_args >= 0);
need_map = 0;
i_argbase = idx_argbase;
DUK_ASSERT(i_argbase >= 0);
duk_push_hobject(ctx, func);
duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_FORMALS);
formals = duk_get_hobject(ctx, -1);
n_formals = 0;
if (formals) {
duk_get_prop_stridx(ctx, -1, DUK_STRIDX_LENGTH);
n_formals = (duk_idx_t) duk_require_int(ctx, -1);
duk_pop(ctx);
}
duk_remove(ctx, -2); /* leave formals on stack for later use */
i_formals = duk_require_top_index(ctx);
DUK_ASSERT(n_formals >= 0);
DUK_ASSERT(formals != NULL || n_formals == 0);
DUK_DDD(DUK_DDDPRINT("func=%!O, formals=%!O, n_formals=%ld",
(duk_heaphdr *) func, (duk_heaphdr *) formals,
(long) n_formals));
/* [ ... formals ] */
/*
* Create required objects:
* - 'arguments' object: array-like, but not an array
* - 'map' object: internal object, tied to 'arguments'
* - 'mappedNames' object: temporary value used during construction
*/
i_arg = duk_push_object_helper(ctx,
DUK_HOBJECT_FLAG_EXTENSIBLE |
DUK_HOBJECT_FLAG_ARRAY_PART |
DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ARGUMENTS),
DUK_BIDX_OBJECT_PROTOTYPE);
DUK_ASSERT(i_arg >= 0);
arg = duk_known_hobject(ctx, -1);
i_map = duk_push_object_helper(ctx,
DUK_HOBJECT_FLAG_EXTENSIBLE |
DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
-1); /* no prototype */
DUK_ASSERT(i_map >= 0);
i_mappednames = duk_push_object_helper(ctx,
DUK_HOBJECT_FLAG_EXTENSIBLE |
DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
-1); /* no prototype */
DUK_ASSERT(i_mappednames >= 0);
/* [ ... formals arguments map mappedNames ] */
DUK_DDD(DUK_DDDPRINT("created arguments related objects: "
"arguments at index %ld -> %!O "
"map at index %ld -> %!O "
"mappednames at index %ld -> %!O",
(long) i_arg, (duk_heaphdr *) duk_get_hobject(ctx, i_arg),
(long) i_map, (duk_heaphdr *) duk_get_hobject(ctx, i_map),
(long) i_mappednames, (duk_heaphdr *) duk_get_hobject(ctx, i_mappednames)));
/*
* Init arguments properties, map, etc.
*/
duk_push_int(ctx, num_stack_args);
duk_xdef_prop_stridx(ctx, i_arg, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_WC);
/*
* Init argument related properties
*/
/* step 11 */
idx = num_stack_args - 1;
while (idx >= 0) {
DUK_DDD(DUK_DDDPRINT("arg idx %ld, argbase=%ld, argidx=%ld",
(long) idx, (long) i_argbase, (long) (i_argbase + idx)));
DUK_DDD(DUK_DDDPRINT("define arguments[%ld]=arg", (long) idx));
duk_dup(ctx, i_argbase + idx);
duk_xdef_prop_index_wec(ctx, i_arg, (duk_uarridx_t) idx);
DUK_DDD(DUK_DDDPRINT("defined arguments[%ld]=arg", (long) idx));
/* step 11.c is relevant only if non-strict (checked in 11.c.ii) */
if (!DUK_HOBJECT_HAS_STRICT(func) && idx < n_formals) {
DUK_ASSERT(formals != NULL);
DUK_DDD(DUK_DDDPRINT("strict function, index within formals (%ld < %ld)",
(long) idx, (long) n_formals));
duk_get_prop_index(ctx, i_formals, idx);
DUK_ASSERT(duk_is_string(ctx, -1));
duk_dup_top(ctx); /* [ ... name name ] */
if (!duk_has_prop(ctx, i_mappednames)) {
/* steps 11.c.ii.1 - 11.c.ii.4, but our internal book-keeping
* differs from the reference model
*/
/* [ ... name ] */
need_map = 1;
DUK_DDD(DUK_DDDPRINT("set mappednames[%s]=%ld",
(const char *) duk_get_string(ctx, -1),
(long) idx));
duk_dup_top(ctx); /* name */
(void) duk_push_uint_to_hstring(ctx, (duk_uint_t) idx); /* index */
duk_xdef_prop_wec(ctx, i_mappednames); /* out of spec, must be configurable */
DUK_DDD(DUK_DDDPRINT("set map[%ld]=%s",
(long) idx,
duk_get_string(ctx, -1)));
duk_dup_top(ctx); /* name */
duk_xdef_prop_index_wec(ctx, i_map, (duk_uarridx_t) idx); /* out of spec, must be configurable */
} else {
/* duk_has_prop() popped the second 'name' */
}
/* [ ... name ] */
duk_pop(ctx); /* pop 'name' */
}
idx--;
}
DUK_DDD(DUK_DDDPRINT("actual arguments processed"));
/* step 12 */
if (need_map) {
DUK_DDD(DUK_DDDPRINT("adding 'map' and 'varenv' to arguments object"));
/* should never happen for a strict callee */
DUK_ASSERT(!DUK_HOBJECT_HAS_STRICT(func));
duk_dup(ctx, i_map);
duk_xdef_prop_stridx(ctx, i_arg, DUK_STRIDX_INT_MAP, DUK_PROPDESC_FLAGS_NONE); /* out of spec, don't care */
/* The variable environment for magic variable bindings needs to be
* given by the caller and recorded in the arguments object.
*
* See E5 Section 10.6, the creation of setters/getters.
*
* The variable environment also provides access to the callee, so
* an explicit (internal) callee property is not needed.
*/
duk_push_hobject(ctx, varenv);
duk_xdef_prop_stridx(ctx, i_arg, DUK_STRIDX_INT_VARENV, DUK_PROPDESC_FLAGS_NONE); /* out of spec, don't care */
}
/* steps 13-14 */
if (DUK_HOBJECT_HAS_STRICT(func)) {
/* Callee/caller are throwers and are not deletable etc. They
* could be implemented as virtual properties, but currently
* there is no support for virtual properties which are accessors
* (only plain virtual properties). This would not be difficult
* to change in duk_hobject_props, but we can make the throwers
* normal, concrete properties just as easily.
*
* Note that the specification requires that the *same* thrower
* built-in object is used here! See E5 Section 10.6 main
* algoritm, step 14, and Section 13.2.3 which describes the
* thrower. See test case test-arguments-throwers.js.
*/
DUK_DDD(DUK_DDDPRINT("strict function, setting caller/callee to throwers"));
duk_xdef_prop_stridx_thrower(ctx, i_arg, DUK_STRIDX_CALLER);
duk_xdef_prop_stridx_thrower(ctx, i_arg, DUK_STRIDX_CALLEE);
} else {
DUK_DDD(DUK_DDDPRINT("non-strict function, setting callee to actual value"));
duk_push_hobject(ctx, func);
duk_xdef_prop_stridx(ctx, i_arg, DUK_STRIDX_CALLEE, DUK_PROPDESC_FLAGS_WC);
}
/* set exotic behavior only after we're done */
if (need_map) {
/* Exotic behaviors are only enabled for arguments objects
* which have a parameter map (see E5 Section 10.6 main
* algorithm, step 12).
*
* In particular, a non-strict arguments object with no
* mapped formals does *NOT* get exotic behavior, even
* for e.g. "caller" property. This seems counterintuitive
* but seems to be the case.
*/
/* cannot be strict (never mapped variables) */
DUK_ASSERT(!DUK_HOBJECT_HAS_STRICT(func));
DUK_DDD(DUK_DDDPRINT("enabling exotic behavior for arguments object"));
DUK_HOBJECT_SET_EXOTIC_ARGUMENTS(arg);
} else {
DUK_DDD(DUK_DDDPRINT("not enabling exotic behavior for arguments object"));
}
DUK_DDD(DUK_DDDPRINT("final arguments related objects: "
"arguments at index %ld -> %!O "
"map at index %ld -> %!O "
"mappednames at index %ld -> %!O",
(long) i_arg, (duk_heaphdr *) duk_get_hobject(ctx, i_arg),
(long) i_map, (duk_heaphdr *) duk_get_hobject(ctx, i_map),
(long) i_mappednames, (duk_heaphdr *) duk_get_hobject(ctx, i_mappednames)));
/* [ args(n) [crud] formals arguments map mappednames ] */
duk_pop_2(ctx);
duk_remove(ctx, -2);
/* [ args [crud] arguments ] */
}
/* Helper for creating the arguments object and adding it to the env record
* on top of the value stack. This helper has a very strict dependency on
* the shape of the input stack.
*/
DUK_LOCAL void duk__handle_createargs_for_call(duk_hthread *thr,
duk_hobject *func,
duk_hobject *env,
duk_idx_t num_stack_args) {
duk_context *ctx = (duk_context *) thr;
DUK_DDD(DUK_DDDPRINT("creating arguments object for function call"));
DUK_ASSERT(thr != NULL);
DUK_ASSERT(func != NULL);
DUK_ASSERT(env != NULL);
DUK_ASSERT(DUK_HOBJECT_HAS_CREATEARGS(func));
DUK_ASSERT(duk_get_top(ctx) >= num_stack_args + 1);
/* [ ... arg1 ... argN envobj ] */
duk__create_arguments_object(thr,
func,
env,
duk_get_top(ctx) - num_stack_args - 1, /* idx_argbase */
num_stack_args);
/* [ ... arg1 ... argN envobj argobj ] */
duk_xdef_prop_stridx(ctx,
-2,
DUK_STRIDX_LC_ARGUMENTS,
DUK_HOBJECT_HAS_STRICT(func) ? DUK_PROPDESC_FLAGS_E : /* strict: non-deletable, non-writable */
DUK_PROPDESC_FLAGS_WE); /* non-strict: non-deletable, writable */
/* [ ... arg1 ... argN envobj ] */
}
/*
* Helper for handling a "bound function" chain when a call is being made.
*
* Follows the bound function chain until a non-bound function is found.
* Prepends the bound arguments to the value stack (at idx_func + 2),
* updating 'num_stack_args' in the process. The 'this' binding is also
* updated if necessary (at idx_func + 1). Note that for constructor calls
* the 'this' binding is never updated by [[BoundThis]].
*
* XXX: bound function chains could be collapsed at bound function creation
* time so that each bound function would point directly to a non-bound
* function. This would make call time handling much easier.
*/
DUK_LOCAL void duk__handle_bound_chain_for_call(duk_hthread *thr,
duk_idx_t idx_func,
duk_idx_t *p_num_stack_args, /* may be changed by call */
duk_bool_t is_constructor_call) {
duk_context *ctx = (duk_context *) thr;
duk_idx_t num_stack_args;
duk_tval *tv_func;
duk_hobject *func;
duk_uint_t sanity;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(p_num_stack_args != NULL);
/* On entry, item at idx_func is a bound, non-lightweight function,
* but we don't rely on that below.
*/
num_stack_args = *p_num_stack_args;
sanity = DUK_HOBJECT_BOUND_CHAIN_SANITY;
do {
duk_idx_t i, len;
tv_func = duk_require_tval(ctx, idx_func);
DUK_ASSERT(tv_func != NULL);
if (DUK_TVAL_IS_LIGHTFUNC(tv_func)) {
/* Lightweight function: never bound, so terminate. */
break;
} else if (DUK_TVAL_IS_OBJECT(tv_func)) {
func = DUK_TVAL_GET_OBJECT(tv_func);
if (!DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
/* Normal non-bound function. */
break;
}
} else {
/* Function.prototype.bind() should never let this happen,
* ugly error message is enough.
*/
DUK_ERROR_INTERNAL(thr);
}
DUK_ASSERT(DUK_TVAL_GET_OBJECT(tv_func) != NULL);
/* XXX: this could be more compact by accessing the internal properties
* directly as own properties (they cannot be inherited, and are not
* externally visible).
*/
DUK_DDD(DUK_DDDPRINT("bound function encountered, ptr=%p, num_stack_args=%ld: %!T",
(void *) DUK_TVAL_GET_OBJECT(tv_func), (long) num_stack_args, tv_func));
/* [ ... func this arg1 ... argN ] */
if (is_constructor_call) {
/* See: tests/ecmascript/test-spec-bound-constructor.js */
DUK_DDD(DUK_DDDPRINT("constructor call: don't update this binding"));
} else {
duk_get_prop_stridx(ctx, idx_func, DUK_STRIDX_INT_THIS);
duk_replace(ctx, idx_func + 1); /* idx_this = idx_func + 1 */
}
/* [ ... func this arg1 ... argN ] */
/* XXX: duk_get_length? */
duk_get_prop_stridx(ctx, idx_func, DUK_STRIDX_INT_ARGS); /* -> [ ... func this arg1 ... argN _Args ] */
duk_get_prop_stridx(ctx, -1, DUK_STRIDX_LENGTH); /* -> [ ... func this arg1 ... argN _Args length ] */
len = (duk_idx_t) duk_require_int(ctx, -1);
duk_pop(ctx);
for (i = 0; i < len; i++) {
/* XXX: very slow - better to bulk allocate a gap, and copy
* from args_array directly (we know it has a compact array
* part, etc).
*/
/* [ ... func this <some bound args> arg1 ... argN _Args ] */
duk_get_prop_index(ctx, -1, i);
duk_insert(ctx, idx_func + 2 + i); /* idx_args = idx_func + 2 */
}
num_stack_args += len; /* must be updated to work properly (e.g. creation of 'arguments') */
duk_pop(ctx);
/* [ ... func this <bound args> arg1 ... argN ] */
duk_get_prop_stridx(ctx, idx_func, DUK_STRIDX_INT_TARGET);
duk_replace(ctx, idx_func); /* replace in stack */
DUK_DDD(DUK_DDDPRINT("bound function handled, num_stack_args=%ld, idx_func=%ld, curr func=%!T",
(long) num_stack_args, (long) idx_func, duk_get_tval(ctx, idx_func)));
} while (--sanity > 0);
if (sanity == 0) {
DUK_ERROR_RANGE(thr, DUK_STR_BOUND_CHAIN_LIMIT);
}
DUK_DDD(DUK_DDDPRINT("final non-bound function is: %!T", duk_get_tval(ctx, idx_func)));
#if defined(DUK_USE_ASSERTIONS)
tv_func = duk_require_tval(ctx, idx_func);
DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv_func) || DUK_TVAL_IS_OBJECT(tv_func));
if (DUK_TVAL_IS_OBJECT(tv_func)) {
func = DUK_TVAL_GET_OBJECT(tv_func);
DUK_ASSERT(func != NULL);
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func) ||
DUK_HOBJECT_HAS_NATFUNC(func));
}
#endif
/* write back */
*p_num_stack_args = num_stack_args;
}
/*
* Helper for setting up var_env and lex_env of an activation,
* assuming it does NOT have the DUK_HOBJECT_FLAG_NEWENV flag.
*/
DUK_LOCAL void duk__handle_oldenv_for_call(duk_hthread *thr,
duk_hobject *func,
duk_activation *act) {
duk_tval *tv;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(func != NULL);
DUK_ASSERT(act != NULL);
DUK_ASSERT(!DUK_HOBJECT_HAS_NEWENV(func));
DUK_ASSERT(!DUK_HOBJECT_HAS_CREATEARGS(func));
tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_INT_LEXENV(thr));
if (tv) {
DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv));
DUK_ASSERT(DUK_HOBJECT_IS_ENV(DUK_TVAL_GET_OBJECT(tv)));
act->lex_env = DUK_TVAL_GET_OBJECT(tv);
tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_INT_VARENV(thr));
if (tv) {
DUK_ASSERT(DUK_TVAL_IS_OBJECT(tv));
DUK_ASSERT(DUK_HOBJECT_IS_ENV(DUK_TVAL_GET_OBJECT(tv)));
act->var_env = DUK_TVAL_GET_OBJECT(tv);
} else {
act->var_env = act->lex_env;
}
} else {
act->lex_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
act->var_env = act->lex_env;
}
DUK_HOBJECT_INCREF_ALLOWNULL(thr, act->lex_env);
DUK_HOBJECT_INCREF_ALLOWNULL(thr, act->var_env);
}
/*
* Helper for updating callee 'caller' property.
*/
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
DUK_LOCAL void duk__update_func_caller_prop(duk_hthread *thr, duk_hobject *func) {
duk_tval *tv_caller;
duk_hobject *h_tmp;
duk_activation *act_callee;
duk_activation *act_caller;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(func != NULL);
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func)); /* bound chain resolved */
DUK_ASSERT(thr->callstack_top >= 1);
if (DUK_HOBJECT_HAS_STRICT(func)) {
/* Strict functions don't get their 'caller' updated. */
return;
}
act_callee = thr->callstack + thr->callstack_top - 1;
act_caller = (thr->callstack_top >= 2 ? act_callee - 1 : NULL);
/* XXX: check .caller writability? */
/* Backup 'caller' property and update its value. */
tv_caller = duk_hobject_find_existing_entry_tval_ptr(thr->heap, func, DUK_HTHREAD_STRING_CALLER(thr));
if (tv_caller) {
/* If caller is global/eval code, 'caller' should be set to
* 'null'.
*
* XXX: there is no exotic flag to infer this correctly now.
* The NEWENV flag is used now which works as intended for
* everything (global code, non-strict eval code, and functions)
* except strict eval code. Bound functions are never an issue
* because 'func' has been resolved to a non-bound function.
*/
if (act_caller) {
/* act_caller->func may be NULL in some finalization cases,
* just treat like we don't know the caller.
*/
if (act_caller->func && !DUK_HOBJECT_HAS_NEWENV(act_caller->func)) {
/* Setting to NULL causes 'caller' to be set to
* 'null' as desired.
*/
act_caller = NULL;
}
}
if (DUK_TVAL_IS_OBJECT(tv_caller)) {
h_tmp = DUK_TVAL_GET_OBJECT(tv_caller);
DUK_ASSERT(h_tmp != NULL);
act_callee->prev_caller = h_tmp;
/* Previous value doesn't need refcount changes because its ownership
* is transferred to prev_caller.
*/
if (act_caller) {
DUK_ASSERT(act_caller->func != NULL);
DUK_TVAL_SET_OBJECT(tv_caller, act_caller->func);
DUK_TVAL_INCREF(thr, tv_caller);
} else {
DUK_TVAL_SET_NULL(tv_caller); /* no incref */
}
} else {
/* 'caller' must only take on 'null' or function value */
DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv_caller));
DUK_ASSERT(act_callee->prev_caller == NULL);
if (act_caller && act_caller->func) {
/* Tolerate act_caller->func == NULL which happens in
* some finalization cases; treat like unknown caller.
*/
DUK_TVAL_SET_OBJECT(tv_caller, act_caller->func);
DUK_TVAL_INCREF(thr, tv_caller);
} else {
DUK_TVAL_SET_NULL(tv_caller); /* no incref */
}
}
}
}
#endif /* DUK_USE_NONSTD_FUNC_CALLER_PROPERTY */
/*
* Determine the effective 'this' binding and coerce the current value
* on the valstack to the effective one (in-place, at idx_this).
*
* The current this value in the valstack (at idx_this) represents either:
* - the caller's requested 'this' binding; or
* - a 'this' binding accumulated from the bound function chain
*
* The final 'this' binding for the target function may still be
* different, and is determined as described in E5 Section 10.4.3.
*
* For global and eval code (E5 Sections 10.4.1 and 10.4.2), we assume
* that the caller has provided the correct 'this' binding explicitly
* when calling, i.e.:
*
* - global code: this=global object
* - direct eval: this=copy from eval() caller's this binding
* - other eval: this=global object
*
* Note: this function may cause a recursive function call with arbitrary
* side effects, because ToObject() may be called.
*/
DUK_LOCAL void duk__coerce_effective_this_binding(duk_hthread *thr,
duk_hobject *func,
duk_idx_t idx_this) {
duk_context *ctx = (duk_context *) thr;
duk_tval *tv_this;
duk_hobject *obj_global;
if (func == NULL || DUK_HOBJECT_HAS_STRICT(func)) {
/* Lightfuncs are always considered strict. */
DUK_DDD(DUK_DDDPRINT("this binding: strict -> use directly"));
return;
}
/* XXX: byte offset */
tv_this = thr->valstack_bottom + idx_this;
switch (DUK_TVAL_GET_TAG(tv_this)) {
case DUK_TAG_OBJECT:
DUK_DDD(DUK_DDDPRINT("this binding: non-strict, object -> use directly"));
break;
case DUK_TAG_UNDEFINED:
case DUK_TAG_NULL:
DUK_DDD(DUK_DDDPRINT("this binding: non-strict, undefined/null -> use global object"));
obj_global = thr->builtins[DUK_BIDX_GLOBAL];
/* XXX: avoid this check somehow */
if (DUK_LIKELY(obj_global != NULL)) {
DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv_this)); /* no need to decref previous value */
DUK_TVAL_SET_OBJECT(tv_this, obj_global);
DUK_HOBJECT_INCREF(thr, obj_global);
} else {
/* This may only happen if built-ins are being "torn down".
* This behavior is out of specification scope.
*/
DUK_D(DUK_DPRINT("this binding: wanted to use global object, but it is NULL -> using undefined instead"));
DUK_ASSERT(!DUK_TVAL_IS_HEAP_ALLOCATED(tv_this)); /* no need to decref previous value */
DUK_TVAL_SET_UNDEFINED(tv_this); /* nothing to incref */
}
break;
default:
/* Plain buffers and lightfuncs are object coerced. Lightfuncs
* very rarely come here however, because the call target would
* need to be a strict non-lightfunc (lightfuncs are considered
* strict) with an explicit lightfunc 'this' binding.
*/
DUK_ASSERT(!DUK_TVAL_IS_UNUSED(tv_this));
DUK_DDD(DUK_DDDPRINT("this binding: non-strict, not object/undefined/null -> use ToObject(value)"));
duk_to_object(ctx, idx_this); /* may have side effects */
break;
}
}
/*
* Shared helper for non-bound func lookup.
*
* Returns duk_hobject * to the final non-bound function (NULL for lightfunc).
*/
DUK_LOCAL duk_hobject *duk__nonbound_func_lookup(duk_context *ctx,
duk_idx_t idx_func,
duk_idx_t *out_num_stack_args,
duk_tval **out_tv_func,
duk_small_uint_t call_flags) {
duk_hthread *thr = (duk_hthread *) ctx;
duk_tval *tv_func;
duk_hobject *func;
for (;;) {
/* Use loop to minimize code size of relookup after bound function case */
tv_func = DUK_GET_TVAL_POSIDX(ctx, idx_func);
DUK_ASSERT(tv_func != NULL);
if (DUK_TVAL_IS_OBJECT(tv_func)) {
func = DUK_TVAL_GET_OBJECT(tv_func);
if (!DUK_HOBJECT_IS_CALLABLE(func)) {
goto not_callable_error;
}
if (DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
duk__handle_bound_chain_for_call(thr, idx_func, out_num_stack_args, call_flags & DUK_CALL_FLAG_CONSTRUCTOR_CALL);
/* The final object may be a normal function or a lightfunc.
* We need to re-lookup tv_func because it may have changed
* (also value stack may have been resized). Loop again to
* do that; we're guaranteed not to come here again.
*/
DUK_ASSERT(DUK_TVAL_IS_OBJECT(duk_require_tval(ctx, idx_func)) ||
DUK_TVAL_IS_LIGHTFUNC(duk_require_tval(ctx, idx_func)));
continue;
}
} else if (DUK_TVAL_IS_LIGHTFUNC(tv_func)) {
func = NULL;
} else {
goto not_callable_error;
}
break;
}
DUK_ASSERT((DUK_TVAL_IS_OBJECT(tv_func) && DUK_HOBJECT_IS_CALLABLE(DUK_TVAL_GET_OBJECT(tv_func))) ||
DUK_TVAL_IS_LIGHTFUNC(tv_func));
DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(func == NULL || (DUK_HOBJECT_IS_COMPFUNC(func) ||
DUK_HOBJECT_IS_NATFUNC(func)));
*out_tv_func = tv_func;
return func;
not_callable_error:
DUK_ASSERT(tv_func != NULL);
#if defined(DUK_USE_PARANOID_ERRORS)
DUK_ERROR_TYPE(thr, DUK_STR_NOT_CALLABLE);
#else
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not callable", duk_push_string_tval_readable(ctx, tv_func));
#endif
DUK_UNREACHABLE();
return NULL; /* never executed */
}
/*
* Value stack resize and stack top adjustment helper.
*
* XXX: This should all be merged to duk_valstack_resize_raw().
*/
DUK_LOCAL void duk__adjust_valstack_and_top(duk_hthread *thr,
duk_idx_t num_stack_args,
duk_idx_t idx_args,
duk_idx_t nregs,
duk_idx_t nargs,
duk_hobject *func) {
duk_context *ctx = (duk_context *) thr;
duk_size_t vs_min_size;
duk_bool_t adjusted_top = 0;
vs_min_size = (thr->valstack_bottom - thr->valstack) + /* bottom of current func */
idx_args; /* bottom of new func */
if (nregs >= 0) {
DUK_ASSERT(nargs >= 0);
DUK_ASSERT(nregs >= nargs);
vs_min_size += nregs;
} else {
/* 'func' wants stack "as is" */
vs_min_size += num_stack_args; /* num entries of new func at entry */
}
if (func == NULL || DUK_HOBJECT_IS_NATFUNC(func)) {
vs_min_size += DUK_VALSTACK_API_ENTRY_MINIMUM; /* Duktape/C API guaranteed entries (on top of args) */
}
vs_min_size += DUK_VALSTACK_INTERNAL_EXTRA; /* + spare */
/* XXX: We can't resize the value stack to a size smaller than the
* current top, so the order of the resize and adjusting the stack
* top depends on the current vs. final size of the value stack.
* The operations could be combined to avoid this, but the proper
* fix is to only grow the value stack on a function call, and only
* shrink it (without throwing if the shrink fails) on function
* return.
*/
if (vs_min_size < (duk_size_t) (thr->valstack_top - thr->valstack)) {
DUK_DDD(DUK_DDDPRINT(("final size smaller, set top before resize")));
DUK_ASSERT(nregs >= 0); /* can't happen when keeping current stack size */
duk_set_top(ctx, idx_args + nargs); /* clamp anything above nargs */
duk_set_top(ctx, idx_args + nregs); /* extend with undefined */
adjusted_top = 1;
}
(void) duk_valstack_resize_raw((duk_context *) thr,
vs_min_size,
DUK_VSRESIZE_FLAG_SHRINK | /* flags */
0 /* no compact */ |
DUK_VSRESIZE_FLAG_THROW);
if (!adjusted_top) {
if (nregs >= 0) {
DUK_ASSERT(nregs >= nargs);
duk_set_top(ctx, idx_args + nargs); /* clamp anything above nargs */
duk_set_top(ctx, idx_args + nregs); /* extend with undefined */
}
}
}
/*
* Manipulate value stack so that exactly 'num_stack_rets' return
* values are at 'idx_retbase' in every case, assuming there are
* 'rc' return values on top of stack.
*
* This is a bit tricky, because the called C function operates in
* the same activation record and may have e.g. popped the stack
* empty (below idx_retbase).
*/
DUK_LOCAL void duk__safe_call_adjust_valstack(duk_hthread *thr, duk_idx_t idx_retbase, duk_idx_t num_stack_rets, duk_idx_t num_actual_rets) {
duk_context *ctx = (duk_context *) thr;
duk_idx_t idx_rcbase;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(idx_retbase >= 0);
DUK_ASSERT(num_stack_rets >= 0);
DUK_ASSERT(num_actual_rets >= 0);
idx_rcbase = duk_get_top(ctx) - num_actual_rets; /* base of known return values */
DUK_DDD(DUK_DDDPRINT("adjust valstack after func call: "
"num_stack_rets=%ld, num_actual_rets=%ld, stack_top=%ld, idx_retbase=%ld, idx_rcbase=%ld",
(long) num_stack_rets, (long) num_actual_rets, (long) duk_get_top(ctx),
(long) idx_retbase, (long) idx_rcbase));
DUK_ASSERT(idx_rcbase >= 0); /* caller must check */
/* Ensure space for final configuration (idx_retbase + num_stack_rets)
* and intermediate configurations.
*/
duk_require_stack_top(ctx,
(idx_rcbase > idx_retbase ? idx_rcbase : idx_retbase) +
num_stack_rets);
/* Chop extra retvals away / extend with undefined. */
duk_set_top(ctx, idx_rcbase + num_stack_rets);
if (idx_rcbase >= idx_retbase) {
duk_idx_t count = idx_rcbase - idx_retbase;
duk_idx_t i;
DUK_DDD(DUK_DDDPRINT("elements at/after idx_retbase have enough to cover func retvals "
"(idx_retbase=%ld, idx_rcbase=%ld)", (long) idx_retbase, (long) idx_rcbase));
/* nuke values at idx_retbase to get the first retval (initially
* at idx_rcbase) to idx_retbase
*/
DUK_ASSERT(count >= 0);
for (i = 0; i < count; i++) {
/* XXX: inefficient; block remove primitive */
duk_remove(ctx, idx_retbase);
}
} else {
duk_idx_t count = idx_retbase - idx_rcbase;
duk_idx_t i;
DUK_DDD(DUK_DDDPRINT("not enough elements at/after idx_retbase to cover func retvals "
"(idx_retbase=%ld, idx_rcbase=%ld)", (long) idx_retbase, (long) idx_rcbase));
/* insert 'undefined' values at idx_rcbase to get the
* return values to idx_retbase
*/
DUK_ASSERT(count > 0);
for (i = 0; i < count; i++) {
/* XXX: inefficient; block insert primitive */
duk_push_undefined(ctx);
duk_insert(ctx, idx_rcbase);
}
}
}
/*
* Misc shared helpers.
*/
/* Get valstack index for the func argument or throw if insane stack. */
DUK_LOCAL duk_idx_t duk__get_idx_func(duk_hthread *thr, duk_idx_t num_stack_args) {
duk_size_t off_stack_top;
duk_size_t off_stack_args;
duk_size_t off_stack_all;
duk_idx_t idx_func; /* valstack index of 'func' and retval (relative to entry valstack_bottom) */
/* Argument validation and func/args offset. */
off_stack_top = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - (duk_uint8_t *) thr->valstack_bottom);
off_stack_args = (duk_size_t) ((duk_size_t) num_stack_args * sizeof(duk_tval));
off_stack_all = off_stack_args + 2 * sizeof(duk_tval);
if (DUK_UNLIKELY(off_stack_all > off_stack_top)) {
/* Since stack indices are not reliable, we can't do anything useful
* here. Invoke the existing setjmp catcher, or if it doesn't exist,
* call the fatal error handler.
*/
DUK_ERROR_TYPE_INVALID_ARGS(thr);
return 0;
}
idx_func = (duk_idx_t) ((off_stack_top - off_stack_all) / sizeof(duk_tval));
return idx_func;
}
/*
* duk_handle_call_protected() and duk_handle_call_unprotected():
* call into a Duktape/C or an Ecmascript function from any state.
*
* Input stack (thr):
*
* [ func this arg1 ... argN ]
*
* Output stack (thr):
*
* [ retval ] (DUK_EXEC_SUCCESS)
* [ errobj ] (DUK_EXEC_ERROR (normal error), protected call)
*
* Even when executing a protected call an error may be thrown in rare cases
* such as an insane num_stack_args argument. If there is no catchpoint for
* such errors, the fatal error handler is called.
*
* The error handling path should be error free, even for out-of-memory
* errors, to ensure safe sandboxing. (As of Duktape 1.4.0 this is not
* yet the case, see XXX notes below.)
*/
DUK_INTERNAL duk_int_t duk_handle_call_protected(duk_hthread *thr,
duk_idx_t num_stack_args,
duk_small_uint_t call_flags) {
duk_context *ctx;
duk_size_t entry_valstack_bottom_index;
duk_size_t entry_valstack_end;
duk_size_t entry_callstack_top;
duk_size_t entry_catchstack_top;
duk_int_t entry_call_recursion_depth;
duk_hthread *entry_curr_thread;
duk_uint_fast8_t entry_thread_state;
duk_instr_t **entry_ptr_curr_pc;
duk_jmpbuf *old_jmpbuf_ptr = NULL;
duk_jmpbuf our_jmpbuf;
duk_idx_t idx_func; /* valstack index of 'func' and retval (relative to entry valstack_bottom) */
/* XXX: Multiple tv_func lookups are now avoided by making a local
* copy of tv_func. Another approach would be to compute an offset
* for tv_func from valstack bottom and recomputing the tv_func
* pointer quickly as valstack + offset instead of calling duk_get_tval().
*/
ctx = (duk_context *) thr;
DUK_UNREF(ctx);
DUK_ASSERT(thr != NULL);
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(num_stack_args >= 0);
/* XXX: currently NULL allocations are not supported; remove if later allowed */
DUK_ASSERT(thr->valstack != NULL);
DUK_ASSERT(thr->callstack != NULL);
DUK_ASSERT(thr->catchstack != NULL);
/* Argument validation and func/args offset. */
idx_func = duk__get_idx_func(thr, num_stack_args);
/* Preliminaries, required by setjmp() handler. Must be careful not
* to throw an unintended error here.
*/
entry_valstack_bottom_index = (duk_size_t) (thr->valstack_bottom - thr->valstack);
#if defined(DUK_USE_PREFER_SIZE)
entry_valstack_end = (duk_size_t) (thr->valstack_end - thr->valstack);
#else
DUK_ASSERT((duk_size_t) (thr->valstack_end - thr->valstack) == thr->valstack_size);
entry_valstack_end = thr->valstack_size;
#endif
entry_callstack_top = thr->callstack_top;
entry_catchstack_top = thr->catchstack_top;
entry_call_recursion_depth = thr->heap->call_recursion_depth;
entry_curr_thread = thr->heap->curr_thread; /* Note: may be NULL if first call */
entry_thread_state = thr->state;
entry_ptr_curr_pc = thr->ptr_curr_pc; /* may be NULL */
DUK_DD(DUK_DDPRINT("duk_handle_call_protected: thr=%p, num_stack_args=%ld, "
"call_flags=0x%08lx (ignorerec=%ld, constructor=%ld), "
"valstack_top=%ld, idx_func=%ld, idx_args=%ld, rec_depth=%ld/%ld, "
"entry_valstack_bottom_index=%ld, entry_callstack_top=%ld, entry_catchstack_top=%ld, "
"entry_call_recursion_depth=%ld, entry_curr_thread=%p, entry_thread_state=%ld",
(void *) thr,
(long) num_stack_args,
(unsigned long) call_flags,
(long) ((call_flags & DUK_CALL_FLAG_IGNORE_RECLIMIT) != 0 ? 1 : 0),
(long) ((call_flags & DUK_CALL_FLAG_CONSTRUCTOR_CALL) != 0 ? 1 : 0),
(long) duk_get_top(ctx),
(long) idx_func,
(long) (idx_func + 2),
(long) thr->heap->call_recursion_depth,
(long) thr->heap->call_recursion_limit,
(long) entry_valstack_bottom_index,
(long) entry_callstack_top,
(long) entry_catchstack_top,
(long) entry_call_recursion_depth,
(void *) entry_curr_thread,
(long) entry_thread_state));
old_jmpbuf_ptr = thr->heap->lj.jmpbuf_ptr;
thr->heap->lj.jmpbuf_ptr = &our_jmpbuf;
#if defined(DUK_USE_CPP_EXCEPTIONS)
try {
#else
DUK_ASSERT(thr->heap->lj.jmpbuf_ptr == &our_jmpbuf);
if (DUK_SETJMP(our_jmpbuf.jb) == 0) {
#endif
/* Call handling and success path. Success path exit cleans
* up almost all state.
*/
duk__handle_call_inner(thr, num_stack_args, call_flags, idx_func);
/* Success path handles */
DUK_ASSERT(thr->heap->call_recursion_depth == entry_call_recursion_depth);
DUK_ASSERT(thr->ptr_curr_pc == entry_ptr_curr_pc);
/* Longjmp state is kept clean in success path */
DUK_ASSERT(thr->heap->lj.type == DUK_LJ_TYPE_UNKNOWN);
DUK_ASSERT(thr->heap->lj.iserror == 0);
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value1));
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value2));
thr->heap->lj.jmpbuf_ptr = old_jmpbuf_ptr;
return DUK_EXEC_SUCCESS;
#if defined(DUK_USE_CPP_EXCEPTIONS)
} catch (duk_internal_exception &exc) {
#else
} else {
#endif
/* Error; error value is in heap->lj.value1. */
#if defined(DUK_USE_CPP_EXCEPTIONS)
DUK_UNREF(exc);
#endif
duk__handle_call_error(thr,
entry_valstack_bottom_index,
entry_valstack_end,
entry_catchstack_top,
entry_callstack_top,
entry_call_recursion_depth,
entry_curr_thread,
entry_thread_state,
entry_ptr_curr_pc,
idx_func,
old_jmpbuf_ptr);
/* Longjmp state is cleaned up by error handling */
DUK_ASSERT(thr->heap->lj.type == DUK_LJ_TYPE_UNKNOWN);
DUK_ASSERT(thr->heap->lj.iserror == 0);
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value1));
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value2));
return DUK_EXEC_ERROR;
}
#if defined(DUK_USE_CPP_EXCEPTIONS)
catch (std::exception &exc) {
const char *what = exc.what();
if (!what) {
what = "unknown";
}
DUK_D(DUK_DPRINT("unexpected c++ std::exception (perhaps thrown by user code)"));
try {
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "caught invalid c++ std::exception '%s' (perhaps thrown by user code)", what);
} catch (duk_internal_exception exc) {
DUK_D(DUK_DPRINT("caught api error thrown from unexpected c++ std::exception"));
DUK_UNREF(exc);
duk__handle_call_error(thr,
entry_valstack_bottom_index,
entry_valstack_end,
entry_catchstack_top,
entry_callstack_top,
entry_call_recursion_depth,
entry_curr_thread,
entry_thread_state,
entry_ptr_curr_pc,
idx_func,
old_jmpbuf_ptr);
return DUK_EXEC_ERROR;
}
} catch (...) {
DUK_D(DUK_DPRINT("unexpected c++ exception (perhaps thrown by user code)"));
try {
DUK_ERROR_TYPE(thr, "caught invalid c++ exception (perhaps thrown by user code)");
} catch (duk_internal_exception exc) {
DUK_D(DUK_DPRINT("caught api error thrown from unexpected c++ exception"));
DUK_UNREF(exc);
duk__handle_call_error(thr,
entry_valstack_bottom_index,
entry_valstack_end,
entry_catchstack_top,
entry_callstack_top,
entry_call_recursion_depth,
entry_curr_thread,
entry_thread_state,
entry_ptr_curr_pc,
idx_func,
old_jmpbuf_ptr);
return DUK_EXEC_ERROR;
}
}
#endif
}
DUK_INTERNAL void duk_handle_call_unprotected(duk_hthread *thr,
duk_idx_t num_stack_args,
duk_small_uint_t call_flags) {
duk_idx_t idx_func; /* valstack index of 'func' and retval (relative to entry valstack_bottom) */
/* Argument validation and func/args offset. */
idx_func = duk__get_idx_func(thr, num_stack_args);
duk__handle_call_inner(thr, num_stack_args, call_flags, idx_func);
}
DUK_LOCAL void duk__handle_call_inner(duk_hthread *thr,
duk_idx_t num_stack_args,
duk_small_uint_t call_flags,
duk_idx_t idx_func) {
duk_context *ctx;
duk_size_t entry_valstack_bottom_index;
duk_size_t entry_valstack_end;
duk_size_t entry_callstack_top;
duk_size_t entry_catchstack_top;
duk_int_t entry_call_recursion_depth;
duk_hthread *entry_curr_thread;
duk_uint_fast8_t entry_thread_state;
duk_instr_t **entry_ptr_curr_pc;
duk_idx_t nargs; /* # argument registers target function wants (< 0 => "as is") */
duk_idx_t nregs; /* # total registers target function wants on entry (< 0 => "as is") */
duk_hobject *func; /* 'func' on stack (borrowed reference) */
duk_tval *tv_func; /* duk_tval ptr for 'func' on stack (borrowed reference) or tv_func_copy */
duk_tval tv_func_copy; /* to avoid relookups */
duk_activation *act;
duk_hobject *env;
duk_ret_t rc;
ctx = (duk_context *) thr;
DUK_ASSERT(thr != NULL);
DUK_ASSERT_CTX_VALID(ctx);
DUK_ASSERT(ctx != NULL);
DUK_ASSERT(num_stack_args >= 0);
/* XXX: currently NULL allocations are not supported; remove if later allowed */
DUK_ASSERT(thr->valstack != NULL);
DUK_ASSERT(thr->callstack != NULL);
DUK_ASSERT(thr->catchstack != NULL);
DUK_DD(DUK_DDPRINT("duk__handle_call_inner: num_stack_args=%ld, call_flags=0x%08lx, top=%ld",
(long) num_stack_args, (long) call_flags, (long) duk_get_top(ctx)));
/*
* Store entry state.
*/
entry_valstack_bottom_index = (duk_size_t) (thr->valstack_bottom - thr->valstack);
#if defined(DUK_USE_PREFER_SIZE)
entry_valstack_end = (duk_size_t) (thr->valstack_end - thr->valstack);
#else
DUK_ASSERT((duk_size_t) (thr->valstack_end - thr->valstack) == thr->valstack_size);
entry_valstack_end = thr->valstack_size;
#endif
entry_callstack_top = thr->callstack_top;
entry_catchstack_top = thr->catchstack_top;
entry_call_recursion_depth = thr->heap->call_recursion_depth;
entry_curr_thread = thr->heap->curr_thread; /* Note: may be NULL if first call */
entry_thread_state = thr->state;
entry_ptr_curr_pc = thr->ptr_curr_pc; /* may be NULL */
/* If thr->ptr_curr_pc is set, sync curr_pc to act->pc. Then NULL
* thr->ptr_curr_pc so that it's not accidentally used with an incorrect
* activation when side effects occur.
*/
duk_hthread_sync_and_null_currpc(thr);
DUK_DD(DUK_DDPRINT("duk__handle_call_inner: thr=%p, num_stack_args=%ld, "
"call_flags=0x%08lx (ignorerec=%ld, constructor=%ld), "
"valstack_top=%ld, idx_func=%ld, idx_args=%ld, rec_depth=%ld/%ld, "
"entry_valstack_bottom_index=%ld, entry_callstack_top=%ld, entry_catchstack_top=%ld, "
"entry_call_recursion_depth=%ld, entry_curr_thread=%p, entry_thread_state=%ld",
(void *) thr,
(long) num_stack_args,
(unsigned long) call_flags,
(long) ((call_flags & DUK_CALL_FLAG_IGNORE_RECLIMIT) != 0 ? 1 : 0),
(long) ((call_flags & DUK_CALL_FLAG_CONSTRUCTOR_CALL) != 0 ? 1 : 0),
(long) duk_get_top(ctx),
(long) idx_func,
(long) (idx_func + 2),
(long) thr->heap->call_recursion_depth,
(long) thr->heap->call_recursion_limit,
(long) entry_valstack_bottom_index,
(long) entry_callstack_top,
(long) entry_catchstack_top,
(long) entry_call_recursion_depth,
(void *) entry_curr_thread,
(long) entry_thread_state));
/*
* Thread state check and book-keeping.
*/
if (thr == thr->heap->curr_thread) {
/* same thread */
if (thr->state != DUK_HTHREAD_STATE_RUNNING) {
/* should actually never happen, but check anyway */
goto thread_state_error;
}
} else {
/* different thread */
DUK_ASSERT(thr->heap->curr_thread == NULL ||
thr->heap->curr_thread->state == DUK_HTHREAD_STATE_RUNNING);
if (thr->state != DUK_HTHREAD_STATE_INACTIVE) {
goto thread_state_error;
}
DUK_HEAP_SWITCH_THREAD(thr->heap, thr);
thr->state = DUK_HTHREAD_STATE_RUNNING;
/* Note: multiple threads may be simultaneously in the RUNNING
* state, but not in the same "resume chain".
*/
}
DUK_ASSERT(thr->heap->curr_thread == thr);
DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_RUNNING);
/*
* C call recursion depth check, which provides a reasonable upper
* bound on maximum C stack size (arbitrary C stack growth is only
* possible by recursive handle_call / handle_safe_call calls).
*/
/* XXX: remove DUK_CALL_FLAG_IGNORE_RECLIMIT flag: there's now the
* reclimit bump?
*/
DUK_ASSERT(thr->heap->call_recursion_depth >= 0);
DUK_ASSERT(thr->heap->call_recursion_depth <= thr->heap->call_recursion_limit);
if (call_flags & DUK_CALL_FLAG_IGNORE_RECLIMIT) {
DUK_DD(DUK_DDPRINT("ignoring reclimit for this call (probably an errhandler call)"));
} else {
if (thr->heap->call_recursion_depth >= thr->heap->call_recursion_limit) {
/* XXX: error message is a bit misleading: we reached a recursion
* limit which is also essentially the same as a C callstack limit
* (except perhaps with some relaxed threading assumptions).
*/
DUK_ERROR_RANGE(thr, DUK_STR_C_CALLSTACK_LIMIT);
}
thr->heap->call_recursion_depth++;
}
/*
* Check the function type, handle bound function chains, and prepare
* parameters for the rest of the call handling. Also figure out the
* effective 'this' binding, which replaces the current value at
* idx_func + 1.
*
* If the target function is a 'bound' one, follow the chain of 'bound'
* functions until a non-bound function is found. During this process,
* bound arguments are 'prepended' to existing ones, and the "this"
* binding is overridden. See E5 Section 15.3.4.5.1.
*
* Lightfunc detection happens here too. Note that lightweight functions
* can be wrapped by (non-lightweight) bound functions so we must resolve
* the bound function chain first.
*/
func = duk__nonbound_func_lookup(ctx, idx_func, &num_stack_args, &tv_func, call_flags);
DUK_TVAL_SET_TVAL(&tv_func_copy, tv_func);
tv_func = &tv_func_copy; /* local copy to avoid relookups */
DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(func == NULL || (DUK_HOBJECT_IS_COMPFUNC(func) ||
DUK_HOBJECT_IS_NATFUNC(func)));
duk__coerce_effective_this_binding(thr, func, idx_func + 1);
DUK_DDD(DUK_DDDPRINT("effective 'this' binding is: %!T",
(duk_tval *) duk_get_tval(ctx, idx_func + 1)));
/* [ ... func this arg1 ... argN ] */
/*
* Setup a preliminary activation and figure out nargs/nregs.
*
* Don't touch valstack_bottom or valstack_top yet so that Duktape API
* calls work normally.
*/
duk_hthread_callstack_grow(thr);
if (thr->callstack_top > 0) {
/*
* Update idx_retval of current activation.
*
* Although it might seem this is not necessary (bytecode executor
* does this for Ecmascript-to-Ecmascript calls; other calls are
* handled here), this turns out to be necessary for handling yield
* and resume. For them, an Ecmascript-to-native call happens, and
* the Ecmascript call's idx_retval must be set for things to work.
*/
(thr->callstack + thr->callstack_top - 1)->idx_retval = entry_valstack_bottom_index + idx_func;
}
DUK_ASSERT(thr->callstack_top < thr->callstack_size);
act = thr->callstack + thr->callstack_top;
thr->callstack_top++;
DUK_ASSERT(thr->callstack_top <= thr->callstack_size);
DUK_ASSERT(thr->valstack_top > thr->valstack_bottom); /* at least effective 'this' */
DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));
act->flags = 0;
/* For now all calls except Ecma-to-Ecma calls prevent a yield. */
act->flags |= DUK_ACT_FLAG_PREVENT_YIELD;
if (call_flags & DUK_CALL_FLAG_CONSTRUCTOR_CALL) {
act->flags |= DUK_ACT_FLAG_CONSTRUCT;
}
if (call_flags & DUK_CALL_FLAG_DIRECT_EVAL) {
act->flags |= DUK_ACT_FLAG_DIRECT_EVAL;
}
/* These base values are never used, but if the compiler doesn't know
* that DUK_ERROR() won't return, these are needed to silence warnings.
* On the other hand, scan-build will warn about the values not being
* used, so add a DUK_UNREF.
*/
nargs = 0; DUK_UNREF(nargs);
nregs = 0; DUK_UNREF(nregs);
if (DUK_LIKELY(func != NULL)) {
if (DUK_HOBJECT_HAS_STRICT(func)) {
act->flags |= DUK_ACT_FLAG_STRICT;
}
if (DUK_HOBJECT_IS_COMPFUNC(func)) {
nargs = ((duk_hcompfunc *) func)->nargs;
nregs = ((duk_hcompfunc *) func)->nregs;
DUK_ASSERT(nregs >= nargs);
} else {
/* True because of call target lookup checks. */
DUK_ASSERT(DUK_HOBJECT_IS_NATFUNC(func));
/* Note: nargs (and nregs) may be negative for a native,
* function, which indicates that the function wants the
* input stack "as is" (i.e. handles "vararg" arguments).
*/
nargs = ((duk_hnatfunc *) func)->nargs;
nregs = nargs;
}
} else {
duk_small_uint_t lf_flags;
DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv_func));
lf_flags = DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv_func);
nargs = DUK_LFUNC_FLAGS_GET_NARGS(lf_flags);
if (nargs == DUK_LFUNC_NARGS_VARARGS) {
nargs = -1; /* vararg */
}
nregs = nargs;
act->flags |= DUK_ACT_FLAG_STRICT;
}
act->func = func; /* NULL for lightfunc */
act->var_env = NULL;
act->lex_env = NULL;
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
act->prev_caller = NULL;
#endif
act->curr_pc = NULL;
#if defined(DUK_USE_DEBUGGER_SUPPORT)
act->prev_line = 0;
#endif
act->idx_bottom = entry_valstack_bottom_index + idx_func + 2;
#if 0 /* topmost activation idx_retval is considered garbage, no need to init */
act->idx_retval = 0;
#endif
DUK_TVAL_SET_TVAL(&act->tv_func, tv_func); /* borrowed, no refcount */
/* XXX: remove the preventcount and make yield walk the callstack?
* Or perhaps just use a single flag, not a counter, faster to just
* set and restore?
*/
if (act->flags & DUK_ACT_FLAG_PREVENT_YIELD) {
/* duk_hthread_callstack_unwind() will decrease this on unwind */
thr->callstack_preventcount++;
}
/* XXX: Is this INCREF necessary? 'func' is always a borrowed
* reference reachable through the value stack? If changed, stack
* unwind code also needs to be fixed to match.
*/
DUK_HOBJECT_INCREF_ALLOWNULL(thr, func); /* act->func */
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
if (func) {
duk__update_func_caller_prop(thr, func);
}
act = thr->callstack + thr->callstack_top - 1;
#endif
/* [ ... func this arg1 ... argN ] */
/*
* Environment record creation and 'arguments' object creation.
* Named function expression name binding is handled by the
* compiler; the compiled function's parent env will contain
* the (immutable) binding already.
*
* This handling is now identical for C and Ecmascript functions.
* C functions always have the 'NEWENV' flag set, so their
* environment record initialization is delayed (which is good).
*
* Delayed creation (on demand) is handled in duk_js_var.c.
*/
DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func)); /* bound function chain has already been resolved */
if (DUK_LIKELY(func != NULL)) {
if (DUK_LIKELY(DUK_HOBJECT_HAS_NEWENV(func))) {
if (DUK_LIKELY(!DUK_HOBJECT_HAS_CREATEARGS(func))) {
/* Use a new environment but there's no 'arguments' object;
* delayed environment initialization. This is the most
* common case.
*/
DUK_ASSERT(act->lex_env == NULL);
DUK_ASSERT(act->var_env == NULL);
} else {
/* Use a new environment and there's an 'arguments' object.
* We need to initialize it right now.
*/
/* third arg: absolute index (to entire valstack) of idx_bottom of new activation */
env = duk_create_activation_environment_record(thr, func, act->idx_bottom);
DUK_ASSERT(env != NULL);
/* [ ... func this arg1 ... argN envobj ] */
DUK_ASSERT(DUK_HOBJECT_HAS_CREATEARGS(func));
duk__handle_createargs_for_call(thr, func, env, num_stack_args);
/* [ ... func this arg1 ... argN envobj ] */
act = thr->callstack + thr->callstack_top - 1;
act->lex_env = env;
act->var_env = env;
DUK_HOBJECT_INCREF(thr, env);
DUK_HOBJECT_INCREF(thr, env); /* XXX: incref by count (2) directly */
duk_pop(ctx);
}
} else {
/* Use existing env (e.g. for non-strict eval); cannot have
* an own 'arguments' object (but can refer to an existing one).
*/
DUK_ASSERT(!DUK_HOBJECT_HAS_CREATEARGS(func));
duk__handle_oldenv_for_call(thr, func, act);
DUK_ASSERT(act->lex_env != NULL);
DUK_ASSERT(act->var_env != NULL);
}
} else {
/* Lightfuncs are always native functions and have "newenv". */
DUK_ASSERT(act->lex_env == NULL);
DUK_ASSERT(act->var_env == NULL);
}
/* [ ... func this arg1 ... argN ] */
/*
* Setup value stack: clamp to 'nargs', fill up to 'nregs'
*
* Value stack may either grow or shrink, depending on the
* number of func registers and the number of actual arguments.
* If nregs >= 0, func wants args clamped to 'nargs'; else it
* wants all args (= 'num_stack_args').
*/
/* XXX: optimize value stack operation */
/* XXX: don't want to shrink allocation here */
duk__adjust_valstack_and_top(thr,
num_stack_args,
idx_func + 2,
nregs,
nargs,
func);
/*
* Determine call type, then finalize activation, shift to
* new value stack bottom, and call the target.
*/
if (func != NULL && DUK_HOBJECT_IS_COMPFUNC(func)) {
/*
* Ecmascript call
*/
duk_tval *tv_ret;
duk_tval *tv_funret;
DUK_ASSERT(func != NULL);
DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
act->curr_pc = DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, (duk_hcompfunc *) func);
thr->valstack_bottom = thr->valstack_bottom + idx_func + 2;
/* keep current valstack_top */
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
/* [ ... func this | arg1 ... argN ] ('this' must precede new bottom) */
/*
* Bytecode executor call.
*
* Execute bytecode, handling any recursive function calls and
* thread resumptions. Returns when execution would return from
* the entry level activation. When the executor returns, a
* single return value is left on the stack top.
*
* The only possible longjmp() is an error (DUK_LJ_TYPE_THROW),
* other types are handled internally by the executor.
*/
/* thr->ptr_curr_pc is set by bytecode executor early on entry */
DUK_ASSERT(thr->ptr_curr_pc == NULL);
DUK_DDD(DUK_DDDPRINT("entering bytecode execution"));
duk_js_execute_bytecode(thr);
DUK_DDD(DUK_DDDPRINT("returned from bytecode execution"));
/* Unwind. */
DUK_ASSERT(thr->catchstack_top >= entry_catchstack_top); /* may need unwind */
DUK_ASSERT(thr->callstack_top == entry_callstack_top + 1);
DUK_ASSERT(thr->callstack_top == entry_callstack_top + 1);
duk_hthread_catchstack_unwind(thr, entry_catchstack_top);
duk_hthread_catchstack_shrink_check(thr);
duk_hthread_callstack_unwind(thr, entry_callstack_top);
duk_hthread_callstack_shrink_check(thr);
thr->valstack_bottom = thr->valstack + entry_valstack_bottom_index;
/* keep current valstack_top */
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
DUK_ASSERT(thr->valstack_top - thr->valstack_bottom >= idx_func + 1);
/* Return value handling. */
/* [ ... func this (crud) retval ] */
tv_ret = thr->valstack_bottom + idx_func;
tv_funret = thr->valstack_top - 1;
#if defined(DUK_USE_FASTINT)
/* Explicit check for fastint downgrade. */
DUK_TVAL_CHKFAST_INPLACE(tv_funret);
#endif
DUK_TVAL_SET_TVAL_UPDREF(thr, tv_ret, tv_funret); /* side effects */
} else {
/*
* Native call.
*/
duk_tval *tv_ret;
duk_tval *tv_funret;
thr->valstack_bottom = thr->valstack_bottom + idx_func + 2;
/* keep current valstack_top */
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
DUK_ASSERT(func == NULL || ((duk_hnatfunc *) func)->func != NULL);
/* [ ... func this | arg1 ... argN ] ('this' must precede new bottom) */
/* For native calls must be NULL so we don't sync back */
DUK_ASSERT(thr->ptr_curr_pc == NULL);
if (func) {
rc = ((duk_hnatfunc *) func)->func((duk_context *) thr);
} else {
duk_c_function funcptr = DUK_TVAL_GET_LIGHTFUNC_FUNCPTR(tv_func);
rc = funcptr((duk_context *) thr);
}
/* Automatic error throwing, retval check. */
if (rc < 0) {
duk_error_throw_from_negative_rc(thr, rc);
DUK_UNREACHABLE();
} else if (rc > 1) {
DUK_ERROR_TYPE(thr, "c function returned invalid rc");
}
DUK_ASSERT(rc == 0 || rc == 1);
/* Unwind. */
DUK_ASSERT(thr->catchstack_top == entry_catchstack_top); /* no need to unwind */
DUK_ASSERT(thr->callstack_top == entry_callstack_top + 1);
duk_hthread_callstack_unwind(thr, entry_callstack_top);
duk_hthread_callstack_shrink_check(thr);
thr->valstack_bottom = thr->valstack + entry_valstack_bottom_index;
/* keep current valstack_top */
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
DUK_ASSERT(thr->valstack_top - thr->valstack_bottom >= idx_func + 1);
/* Return value handling. */
/* XXX: should this happen in the callee's activation or after unwinding? */
tv_ret = thr->valstack_bottom + idx_func;
if (rc == 0) {
DUK_TVAL_SET_UNDEFINED_UPDREF(thr, tv_ret); /* side effects */
} else {
/* [ ... func this (crud) retval ] */
tv_funret = thr->valstack_top - 1;
#if defined(DUK_USE_FASTINT)
/* Explicit check for fastint downgrade. */
DUK_TVAL_CHKFAST_INPLACE(tv_funret);
#endif
DUK_TVAL_SET_TVAL_UPDREF(thr, tv_ret, tv_funret); /* side effects */
}
}
duk_set_top(ctx, idx_func + 1); /* XXX: unnecessary, handle in adjust */
/* [ ... retval ] */
/* Ensure there is internal valstack spare before we exit; this may
* throw an alloc error. The same guaranteed size must be available
* as before the call. This is not optimal now: we store the valstack
* allocated size during entry; this value may be higher than the
* minimal guarantee for an application.
*/
/* XXX: we should never shrink here; when we error out later, we'd
* need to potentially grow the value stack in error unwind which could
* cause another error.
*/
(void) duk_valstack_resize_raw((duk_context *) thr,
entry_valstack_end, /* same as during entry */
DUK_VSRESIZE_FLAG_SHRINK | /* flags */
DUK_VSRESIZE_FLAG_COMPACT |
DUK_VSRESIZE_FLAG_THROW);
/* Restore entry thread executor curr_pc stack frame pointer. */
thr->ptr_curr_pc = entry_ptr_curr_pc;
DUK_HEAP_SWITCH_THREAD(thr->heap, entry_curr_thread); /* may be NULL */
thr->state = (duk_uint8_t) entry_thread_state;
DUK_ASSERT((thr->state == DUK_HTHREAD_STATE_INACTIVE && thr->heap->curr_thread == NULL) || /* first call */
(thr->state == DUK_HTHREAD_STATE_INACTIVE && thr->heap->curr_thread != NULL) || /* other call */
(thr->state == DUK_HTHREAD_STATE_RUNNING && thr->heap->curr_thread == thr)); /* current thread */
thr->heap->call_recursion_depth = entry_call_recursion_depth;
/* If the debugger is active we need to force an interrupt so that
* debugger breakpoints are rechecked. This is important for function
* calls caused by side effects (e.g. when doing a DUK_OP_GETPROP), see
* GH-303. Only needed for success path, error path always causes a
* breakpoint recheck in the executor. It would be enough to set this
* only when returning to an Ecmascript activation, but setting the flag
* on every return should have no ill effect.
*/
#if defined(DUK_USE_DEBUGGER_SUPPORT)
if (DUK_HEAP_IS_DEBUGGER_ATTACHED(thr->heap)) {
DUK_DD(DUK_DDPRINT("returning with debugger enabled, force interrupt"));
DUK_ASSERT(thr->interrupt_counter <= thr->interrupt_init);
thr->interrupt_init -= thr->interrupt_counter;
thr->interrupt_counter = 0;
thr->heap->dbg_force_restart = 1;
}
#endif
#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
duk__interrupt_fixup(thr, entry_curr_thread);
#endif
return;
thread_state_error:
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "invalid thread state for call (%ld)", (long) thr->state);
DUK_UNREACHABLE();
return; /* never executed */
}
DUK_LOCAL void duk__handle_call_error(duk_hthread *thr,
duk_size_t entry_valstack_bottom_index,
duk_size_t entry_valstack_end,
duk_size_t entry_catchstack_top,
duk_size_t entry_callstack_top,
duk_int_t entry_call_recursion_depth,
duk_hthread *entry_curr_thread,
duk_uint_fast8_t entry_thread_state,
duk_instr_t **entry_ptr_curr_pc,
duk_idx_t idx_func,
duk_jmpbuf *old_jmpbuf_ptr) {
duk_context *ctx;
duk_tval *tv_ret;
ctx = (duk_context *) thr;
DUK_DDD(DUK_DDDPRINT("error caught during duk__handle_call_inner(): %!T",
(duk_tval *) &thr->heap->lj.value1));
/* Other longjmp types are handled by executor before propagating
* the error here.
*/
DUK_ASSERT(thr->heap->lj.type == DUK_LJ_TYPE_THROW);
DUK_ASSERT(thr->callstack_top >= entry_callstack_top);
DUK_ASSERT(thr->catchstack_top >= entry_catchstack_top);
/* We don't need to sync back thr->ptr_curr_pc here because
* the bytecode executor always has a setjmp catchpoint which
* does that before errors propagate to here.
*/
DUK_ASSERT(thr->ptr_curr_pc == NULL);
/* Restore the previous setjmp catcher so that any error in
* error handling will propagate outwards rather than re-enter
* the same handler. However, the error handling path must be
* designed to be error free so that sandboxing guarantees are
* reliable, see e.g. https://github.com/svaarala/duktape/issues/476.
*/
thr->heap->lj.jmpbuf_ptr = old_jmpbuf_ptr;
/* XXX: callstack unwind may now throw an error when closing
* scopes; this is a sandboxing issue, described in:
* https://github.com/svaarala/duktape/issues/476
*/
duk_hthread_catchstack_unwind(thr, entry_catchstack_top);
duk_hthread_catchstack_shrink_check(thr);
duk_hthread_callstack_unwind(thr, entry_callstack_top);
duk_hthread_callstack_shrink_check(thr);
thr->valstack_bottom = thr->valstack + entry_valstack_bottom_index;
tv_ret = thr->valstack_bottom + idx_func; /* XXX: byte offset? */
DUK_TVAL_SET_TVAL_UPDREF(thr, tv_ret, &thr->heap->lj.value1); /* side effects */
#if defined(DUK_USE_FASTINT)
/* Explicit check for fastint downgrade. */
DUK_TVAL_CHKFAST_INPLACE(tv_ret);
#endif
duk_set_top(ctx, idx_func + 1); /* XXX: could be eliminated with valstack adjust */
/* [ ... errobj ] */
/* Ensure there is internal valstack spare before we exit; this may
* throw an alloc error. The same guaranteed size must be available
* as before the call. This is not optimal now: we store the valstack
* allocated size during entry; this value may be higher than the
* minimal guarantee for an application.
*/
/* XXX: this needs to be reworked so that we never shrink the value
* stack on function entry so that we never need to grow it here.
* Needing to grow here is a sandboxing issue because we need to
* allocate which may cause an error in the error handling path
* and thus propagate an error out of a protected call.
*/
(void) duk_valstack_resize_raw((duk_context *) thr,
entry_valstack_end, /* same as during entry */
DUK_VSRESIZE_FLAG_SHRINK | /* flags */
DUK_VSRESIZE_FLAG_COMPACT |
DUK_VSRESIZE_FLAG_THROW);
/* These are just convenience "wiping" of state. Side effects should
* not be an issue here: thr->heap and thr->heap->lj have a stable
* pointer. Finalizer runs etc capture even out-of-memory errors so
* nothing should throw here.
*/
thr->heap->lj.type = DUK_LJ_TYPE_UNKNOWN;
thr->heap->lj.iserror = 0;
DUK_TVAL_SET_UNDEFINED_UPDREF(thr, &thr->heap->lj.value1); /* side effects */
DUK_TVAL_SET_UNDEFINED_UPDREF(thr, &thr->heap->lj.value2); /* side effects */
/* Restore entry thread executor curr_pc stack frame pointer. */
thr->ptr_curr_pc = entry_ptr_curr_pc;
DUK_HEAP_SWITCH_THREAD(thr->heap, entry_curr_thread); /* may be NULL */
thr->state = (duk_uint8_t) entry_thread_state;
DUK_ASSERT((thr->state == DUK_HTHREAD_STATE_INACTIVE && thr->heap->curr_thread == NULL) || /* first call */
(thr->state == DUK_HTHREAD_STATE_INACTIVE && thr->heap->curr_thread != NULL) || /* other call */
(thr->state == DUK_HTHREAD_STATE_RUNNING && thr->heap->curr_thread == thr)); /* current thread */
thr->heap->call_recursion_depth = entry_call_recursion_depth;
/* If the debugger is active we need to force an interrupt so that
* debugger breakpoints are rechecked. This is important for function
* calls caused by side effects (e.g. when doing a DUK_OP_GETPROP), see
* GH-303. Only needed for success path, error path always causes a
* breakpoint recheck in the executor. It would be enough to set this
* only when returning to an Ecmascript activation, but setting the flag
* on every return should have no ill effect.
*/
#if defined(DUK_USE_DEBUGGER_SUPPORT)
if (DUK_HEAP_IS_DEBUGGER_ATTACHED(thr->heap)) {
DUK_DD(DUK_DDPRINT("returning with debugger enabled, force interrupt"));
DUK_ASSERT(thr->interrupt_counter <= thr->interrupt_init);
thr->interrupt_init -= thr->interrupt_counter;
thr->interrupt_counter = 0;
thr->heap->dbg_force_restart = 1;
}
#endif
#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
duk__interrupt_fixup(thr, entry_curr_thread);
#endif
}
/*
* duk_handle_safe_call(): make a "C protected call" within the
* current activation.
*
* The allowed thread states for making a call are the same as for
* duk_handle_call_xxx().
*
* Error handling is similar to duk_handle_call_xxx(); errors may be thrown
* (and result in a fatal error) for insane arguments.
*/
/* XXX: bump preventcount by one for the duration of this call? */
DUK_INTERNAL duk_int_t duk_handle_safe_call(duk_hthread *thr,
duk_safe_call_function func,
void *udata,
duk_idx_t num_stack_args,
duk_idx_t num_stack_rets) {
duk_context *ctx = (duk_context *) thr;
duk_size_t entry_valstack_bottom_index;
duk_size_t entry_callstack_top;
duk_size_t entry_catchstack_top;
duk_int_t entry_call_recursion_depth;
duk_hthread *entry_curr_thread;
duk_uint_fast8_t entry_thread_state;
duk_instr_t **entry_ptr_curr_pc;
duk_jmpbuf *old_jmpbuf_ptr = NULL;
duk_jmpbuf our_jmpbuf;
duk_idx_t idx_retbase;
duk_int_t retval;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(ctx != NULL);
/* Note: careful with indices like '-x'; if 'x' is zero, it refers to bottom */
entry_valstack_bottom_index = (duk_size_t) (thr->valstack_bottom - thr->valstack);
entry_callstack_top = thr->callstack_top;
entry_catchstack_top = thr->catchstack_top;
entry_call_recursion_depth = thr->heap->call_recursion_depth;
entry_curr_thread = thr->heap->curr_thread; /* Note: may be NULL if first call */
entry_thread_state = thr->state;
entry_ptr_curr_pc = thr->ptr_curr_pc; /* may be NULL */
idx_retbase = duk_get_top(ctx) - num_stack_args; /* Note: not a valid stack index if num_stack_args == 0 */
/* Note: cannot portably debug print a function pointer, hence 'func' not printed! */
DUK_DD(DUK_DDPRINT("duk_handle_safe_call: thr=%p, num_stack_args=%ld, num_stack_rets=%ld, "
"valstack_top=%ld, idx_retbase=%ld, rec_depth=%ld/%ld, "
"entry_valstack_bottom_index=%ld, entry_callstack_top=%ld, entry_catchstack_top=%ld, "
"entry_call_recursion_depth=%ld, entry_curr_thread=%p, entry_thread_state=%ld",
(void *) thr,
(long) num_stack_args,
(long) num_stack_rets,
(long) duk_get_top(ctx),
(long) idx_retbase,
(long) thr->heap->call_recursion_depth,
(long) thr->heap->call_recursion_limit,
(long) entry_valstack_bottom_index,
(long) entry_callstack_top,
(long) entry_catchstack_top,
(long) entry_call_recursion_depth,
(void *) entry_curr_thread,
(long) entry_thread_state));
if (idx_retbase < 0) {
/* Since stack indices are not reliable, we can't do anything useful
* here. Invoke the existing setjmp catcher, or if it doesn't exist,
* call the fatal error handler.
*/
DUK_ERROR_TYPE_INVALID_ARGS(thr);
}
/* setjmp catchpoint setup */
old_jmpbuf_ptr = thr->heap->lj.jmpbuf_ptr;
thr->heap->lj.jmpbuf_ptr = &our_jmpbuf;
#if defined(DUK_USE_CPP_EXCEPTIONS)
try {
#else
DUK_ASSERT(thr->heap->lj.jmpbuf_ptr == &our_jmpbuf);
if (DUK_SETJMP(our_jmpbuf.jb) == 0) {
/* Success path. */
#endif
DUK_DDD(DUK_DDDPRINT("safe_call setjmp catchpoint setup complete"));
duk__handle_safe_call_inner(thr,
func,
udata,
idx_retbase,
num_stack_rets,
entry_valstack_bottom_index,
entry_callstack_top,
entry_catchstack_top);
/* Longjmp state is kept clean in success path */
DUK_ASSERT(thr->heap->lj.type == DUK_LJ_TYPE_UNKNOWN);
DUK_ASSERT(thr->heap->lj.iserror == 0);
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value1));
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value2));
/* Note: either pointer may be NULL (at entry), so don't assert */
thr->heap->lj.jmpbuf_ptr = old_jmpbuf_ptr;
retval = DUK_EXEC_SUCCESS;
#if defined(DUK_USE_CPP_EXCEPTIONS)
} catch (duk_internal_exception &exc) {
DUK_UNREF(exc);
#else
} else {
/* Error path. */
#endif
duk__handle_safe_call_error(thr,
idx_retbase,
num_stack_rets,
entry_valstack_bottom_index,
entry_callstack_top,
entry_catchstack_top,
old_jmpbuf_ptr);
/* Longjmp state is cleaned up by error handling */
DUK_ASSERT(thr->heap->lj.type == DUK_LJ_TYPE_UNKNOWN);
DUK_ASSERT(thr->heap->lj.iserror == 0);
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value1));
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(&thr->heap->lj.value2));
retval = DUK_EXEC_ERROR;
}
#if defined(DUK_USE_CPP_EXCEPTIONS)
catch (std::exception &exc) {
const char *what = exc.what();
if (!what) {
what = "unknown";
}
DUK_D(DUK_DPRINT("unexpected c++ std::exception (perhaps thrown by user code)"));
try {
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "caught invalid c++ std::exception '%s' (perhaps thrown by user code)", what);
} catch (duk_internal_exception exc) {
DUK_D(DUK_DPRINT("caught api error thrown from unexpected c++ std::exception"));
DUK_UNREF(exc);
duk__handle_safe_call_error(thr,
idx_retbase,
num_stack_rets,
entry_valstack_bottom_index,
entry_callstack_top,
entry_catchstack_top,
old_jmpbuf_ptr);
retval = DUK_EXEC_ERROR;
}
} catch (...) {
DUK_D(DUK_DPRINT("unexpected c++ exception (perhaps thrown by user code)"));
try {
DUK_ERROR_TYPE(thr, "caught invalid c++ exception (perhaps thrown by user code)");
} catch (duk_internal_exception exc) {
DUK_D(DUK_DPRINT("caught api error thrown from unexpected c++ exception"));
DUK_UNREF(exc);
duk__handle_safe_call_error(thr,
idx_retbase,
num_stack_rets,
entry_valstack_bottom_index,
entry_callstack_top,
entry_catchstack_top,
old_jmpbuf_ptr);
retval = DUK_EXEC_ERROR;
}
}
#endif
DUK_ASSERT(thr->heap->lj.jmpbuf_ptr == old_jmpbuf_ptr); /* success/error path both do this */
duk__handle_safe_call_shared(thr,
idx_retbase,
num_stack_rets,
entry_call_recursion_depth,
entry_curr_thread,
entry_thread_state,
entry_ptr_curr_pc);
return retval;
}
DUK_LOCAL void duk__handle_safe_call_inner(duk_hthread *thr,
duk_safe_call_function func,
void *udata,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets,
duk_size_t entry_valstack_bottom_index,
duk_size_t entry_callstack_top,
duk_size_t entry_catchstack_top) {
duk_context *ctx;
duk_ret_t rc;
DUK_ASSERT(thr != NULL);
ctx = (duk_context *) thr;
DUK_ASSERT_CTX_VALID(ctx);
DUK_UNREF(entry_valstack_bottom_index);
DUK_UNREF(entry_callstack_top);
DUK_UNREF(entry_catchstack_top);
/*
* Thread state check and book-keeping.
*/
if (thr == thr->heap->curr_thread) {
/* same thread */
if (thr->state != DUK_HTHREAD_STATE_RUNNING) {
/* should actually never happen, but check anyway */
goto thread_state_error;
}
} else {
/* different thread */
DUK_ASSERT(thr->heap->curr_thread == NULL ||
thr->heap->curr_thread->state == DUK_HTHREAD_STATE_RUNNING);
if (thr->state != DUK_HTHREAD_STATE_INACTIVE) {
goto thread_state_error;
}
DUK_HEAP_SWITCH_THREAD(thr->heap, thr);
thr->state = DUK_HTHREAD_STATE_RUNNING;
/* Note: multiple threads may be simultaneously in the RUNNING
* state, but not in the same "resume chain".
*/
}
DUK_ASSERT(thr->heap->curr_thread == thr);
DUK_ASSERT(thr->state == DUK_HTHREAD_STATE_RUNNING);
/*
* Recursion limit check.
*
* Note: there is no need for an "ignore recursion limit" flag
* for duk_handle_safe_call now.
*/
DUK_ASSERT(thr->heap->call_recursion_depth >= 0);
DUK_ASSERT(thr->heap->call_recursion_depth <= thr->heap->call_recursion_limit);
if (thr->heap->call_recursion_depth >= thr->heap->call_recursion_limit) {
/* XXX: error message is a bit misleading: we reached a recursion
* limit which is also essentially the same as a C callstack limit
* (except perhaps with some relaxed threading assumptions).
*/
DUK_ERROR_RANGE(thr, DUK_STR_C_CALLSTACK_LIMIT);
}
thr->heap->call_recursion_depth++;
/*
* Valstack spare check
*/
duk_require_stack(ctx, 0); /* internal spare */
/*
* Make the C call
*/
rc = func(ctx, udata);
DUK_DDD(DUK_DDDPRINT("safe_call, func rc=%ld", (long) rc));
/*
* Valstack manipulation for results.
*/
/* we're running inside the caller's activation, so no change in call/catch stack or valstack bottom */
DUK_ASSERT(thr->callstack_top == entry_callstack_top);
DUK_ASSERT(thr->catchstack_top == entry_catchstack_top);
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT((duk_size_t) (thr->valstack_bottom - thr->valstack) == entry_valstack_bottom_index);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
if (rc < 0) {
duk_error_throw_from_negative_rc(thr, rc);
}
DUK_ASSERT(rc >= 0);
if (duk_get_top(ctx) < rc) {
DUK_ERROR_RANGE(thr, "not enough stack values for safe_call rc");
}
DUK_ASSERT(thr->catchstack_top == entry_catchstack_top); /* no need to unwind */
DUK_ASSERT(thr->callstack_top == entry_callstack_top);
duk__safe_call_adjust_valstack(thr, idx_retbase, num_stack_rets, rc);
return;
thread_state_error:
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "invalid thread state for safe_call (%ld)", (long) thr->state);
DUK_UNREACHABLE();
}
DUK_LOCAL void duk__handle_safe_call_error(duk_hthread *thr,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets,
duk_size_t entry_valstack_bottom_index,
duk_size_t entry_callstack_top,
duk_size_t entry_catchstack_top,
duk_jmpbuf *old_jmpbuf_ptr) {
duk_context *ctx;
DUK_ASSERT(thr != NULL);
ctx = (duk_context *) thr;
DUK_ASSERT_CTX_VALID(ctx);
/*
* Error during call. The error value is at heap->lj.value1.
*
* The very first thing we do is restore the previous setjmp catcher.
* This means that any error in error handling will propagate outwards
* instead of causing a setjmp() re-entry above.
*/
DUK_DDD(DUK_DDDPRINT("error caught during protected duk_handle_safe_call()"));
/* Other longjmp types are handled by executor before propagating
* the error here.
*/
DUK_ASSERT(thr->heap->lj.type == DUK_LJ_TYPE_THROW);
DUK_ASSERT(thr->callstack_top >= entry_callstack_top);
DUK_ASSERT(thr->catchstack_top >= entry_catchstack_top);
/* Note: either pointer may be NULL (at entry), so don't assert. */
thr->heap->lj.jmpbuf_ptr = old_jmpbuf_ptr;
DUK_ASSERT(thr->catchstack_top >= entry_catchstack_top);
DUK_ASSERT(thr->callstack_top >= entry_callstack_top);
duk_hthread_catchstack_unwind(thr, entry_catchstack_top);
duk_hthread_catchstack_shrink_check(thr);
duk_hthread_callstack_unwind(thr, entry_callstack_top);
duk_hthread_callstack_shrink_check(thr);
thr->valstack_bottom = thr->valstack + entry_valstack_bottom_index;
/* [ ... | (crud) ] */
/* XXX: space in valstack? see discussion in duk_handle_call_xxx(). */
duk_push_tval(ctx, &thr->heap->lj.value1);
/* [ ... | (crud) errobj ] */
DUK_ASSERT(duk_get_top(ctx) >= 1); /* at least errobj must be on stack */
/* check that the valstack has space for the final amount and any
* intermediate space needed; this is unoptimal but should be safe
*/
duk_require_stack_top(ctx, idx_retbase + num_stack_rets); /* final configuration */
duk_require_stack(ctx, num_stack_rets);
duk__safe_call_adjust_valstack(thr, idx_retbase, num_stack_rets, 1); /* 1 = num actual 'return values' */
/* [ ... | ] or [ ... | errobj (M * undefined)] where M = num_stack_rets - 1 */
/* These are just convenience "wiping" of state. Side effects should
* not be an issue here: thr->heap and thr->heap->lj have a stable
* pointer. Finalizer runs etc capture even out-of-memory errors so
* nothing should throw here.
*/
thr->heap->lj.type = DUK_LJ_TYPE_UNKNOWN;
thr->heap->lj.iserror = 0;
DUK_TVAL_SET_UNDEFINED_UPDREF(thr, &thr->heap->lj.value1); /* side effects */
DUK_TVAL_SET_UNDEFINED_UPDREF(thr, &thr->heap->lj.value2); /* side effects */
}
DUK_LOCAL void duk__handle_safe_call_shared(duk_hthread *thr,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets,
duk_int_t entry_call_recursion_depth,
duk_hthread *entry_curr_thread,
duk_uint_fast8_t entry_thread_state,
duk_instr_t **entry_ptr_curr_pc) {
duk_context *ctx;
DUK_ASSERT(thr != NULL);
ctx = (duk_context *) thr;
DUK_ASSERT_CTX_VALID(ctx);
DUK_UNREF(ctx);
DUK_UNREF(idx_retbase);
DUK_UNREF(num_stack_rets);
/* Restore entry thread executor curr_pc stack frame pointer. */
thr->ptr_curr_pc = entry_ptr_curr_pc;
/* XXX: because we unwind stacks above, thr->heap->curr_thread is at
* risk of pointing to an already freed thread. This was indeed the
* case in test-bug-multithread-valgrind.c, until duk_handle_call()
* was fixed to restore thr->heap->curr_thread before rethrowing an
* uncaught error.
*/
DUK_HEAP_SWITCH_THREAD(thr->heap, entry_curr_thread); /* may be NULL */
thr->state = (duk_uint8_t) entry_thread_state;
DUK_ASSERT((thr->state == DUK_HTHREAD_STATE_INACTIVE && thr->heap->curr_thread == NULL) || /* first call */
(thr->state == DUK_HTHREAD_STATE_INACTIVE && thr->heap->curr_thread != NULL) || /* other call */
(thr->state == DUK_HTHREAD_STATE_RUNNING && thr->heap->curr_thread == thr)); /* current thread */
thr->heap->call_recursion_depth = entry_call_recursion_depth;
/* stack discipline consistency check */
DUK_ASSERT(duk_get_top(ctx) == idx_retbase + num_stack_rets);
/* A debugger forced interrupt check is not needed here, as
* problematic safe calls are not caused by side effects.
*/
#if defined(DUK_USE_INTERRUPT_COUNTER) && defined(DUK_USE_DEBUG)
duk__interrupt_fixup(thr, entry_curr_thread);
#endif
}
/*
* Helper for handling an Ecmascript-to-Ecmascript call or an Ecmascript
* function (initial) Duktape.Thread.resume().
*
* Compared to normal calls handled by duk_handle_call(), there are a
* bunch of differences:
*
* - the call is never protected
* - there is no C recursion depth increase (hence an "ignore recursion
* limit" flag is not applicable)
* - instead of making the call, this helper just performs the thread
* setup and returns; the bytecode executor then restarts execution
* internally
* - ecmascript functions are never 'vararg' functions (they access
* varargs through the 'arguments' object)
*
* The callstack of the target contains an earlier Ecmascript call in case
* of an Ecmascript-to-Ecmascript call (whose idx_retval is updated), or
* is empty in case of an initial Duktape.Thread.resume().
*
* The first thing to do here is to figure out whether an ecma-to-ecma
* call is actually possible. It's not always the case if the target is
* a bound function; the final function may be native. In that case,
* return an error so caller can fall back to a normal call path.
*/
DUK_INTERNAL duk_bool_t duk_handle_ecma_call_setup(duk_hthread *thr,
duk_idx_t num_stack_args,
duk_small_uint_t call_flags) {
duk_context *ctx = (duk_context *) thr;
duk_size_t entry_valstack_bottom_index;
duk_idx_t idx_func; /* valstack index of 'func' and retval (relative to entry valstack_bottom) */
duk_idx_t idx_args; /* valstack index of start of args (arg1) (relative to entry valstack_bottom) */
duk_idx_t nargs; /* # argument registers target function wants (< 0 => never for ecma calls) */
duk_idx_t nregs; /* # total registers target function wants on entry (< 0 => never for ecma calls) */
duk_hobject *func; /* 'func' on stack (borrowed reference) */
duk_tval *tv_func; /* duk_tval ptr for 'func' on stack (borrowed reference) */
duk_activation *act;
duk_hobject *env;
duk_bool_t use_tailcall;
duk_instr_t **entry_ptr_curr_pc;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(ctx != NULL);
DUK_ASSERT(!((call_flags & DUK_CALL_FLAG_IS_RESUME) != 0 && (call_flags & DUK_CALL_FLAG_IS_TAILCALL) != 0));
/* XXX: assume these? */
DUK_ASSERT(thr->valstack != NULL);
DUK_ASSERT(thr->callstack != NULL);
DUK_ASSERT(thr->catchstack != NULL);
/* no need to handle thread state book-keeping here */
DUK_ASSERT((call_flags & DUK_CALL_FLAG_IS_RESUME) != 0 ||
(thr->state == DUK_HTHREAD_STATE_RUNNING &&
thr->heap->curr_thread == thr));
/* If thr->ptr_curr_pc is set, sync curr_pc to act->pc. Then NULL
* thr->ptr_curr_pc so that it's not accidentally used with an incorrect
* activation when side effects occur. If we end up not making the
* call we must restore the value.
*/
entry_ptr_curr_pc = thr->ptr_curr_pc;
duk_hthread_sync_and_null_currpc(thr);
/* if a tail call:
* - an Ecmascript activation must be on top of the callstack
* - there cannot be any active catchstack entries
*/
#if defined(DUK_USE_ASSERTIONS)
if (call_flags & DUK_CALL_FLAG_IS_TAILCALL) {
duk_size_t our_callstack_index;
duk_size_t i;
DUK_ASSERT(thr->callstack_top >= 1);
our_callstack_index = thr->callstack_top - 1;
DUK_ASSERT_DISABLE(our_callstack_index >= 0);
DUK_ASSERT(our_callstack_index < thr->callstack_size);
DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack + our_callstack_index) != NULL);
DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->callstack + our_callstack_index)));
/* No entry in the catchstack which would actually catch a
* throw can refer to the callstack entry being reused.
* There *can* be catchstack entries referring to the current
* callstack entry as long as they don't catch (e.g. label sites).
*/
for (i = 0; i < thr->catchstack_top; i++) {
DUK_ASSERT(thr->catchstack[i].callstack_index < our_callstack_index || /* refer to callstack entries below current */
DUK_CAT_GET_TYPE(thr->catchstack + i) == DUK_CAT_TYPE_LABEL); /* or a non-catching entry */
}
}
#endif /* DUK_USE_ASSERTIONS */
entry_valstack_bottom_index = (duk_size_t) (thr->valstack_bottom - thr->valstack);
/* XXX: rework */
idx_func = duk_normalize_index(thr, -num_stack_args - 2);
idx_args = idx_func + 2;
DUK_DD(DUK_DDPRINT("handle_ecma_call_setup: thr=%p, "
"num_stack_args=%ld, call_flags=0x%08lx (resume=%ld, tailcall=%ld), "
"idx_func=%ld, idx_args=%ld, entry_valstack_bottom_index=%ld",
(void *) thr,
(long) num_stack_args,
(unsigned long) call_flags,
(long) ((call_flags & DUK_CALL_FLAG_IS_RESUME) != 0 ? 1 : 0),
(long) ((call_flags & DUK_CALL_FLAG_IS_TAILCALL) != 0 ? 1 : 0),
(long) idx_func,
(long) idx_args,
(long) entry_valstack_bottom_index));
if (DUK_UNLIKELY(idx_func < 0 || idx_args < 0)) {
/* XXX: assert? compiler is responsible for this never happening */
DUK_ERROR_TYPE_INVALID_ARGS(thr);
}
/*
* Check the function type, handle bound function chains, and prepare
* parameters for the rest of the call handling. Also figure out the
* effective 'this' binding, which replaces the current value at
* idx_func + 1.
*
* If the target function is a 'bound' one, follow the chain of 'bound'
* functions until a non-bound function is found. During this process,
* bound arguments are 'prepended' to existing ones, and the "this"
* binding is overridden. See E5 Section 15.3.4.5.1.
*
* If the final target function cannot be handled by an ecma-to-ecma
* call, return to the caller with a return value indicating this case.
* The bound chain is resolved and the caller can resume with a plain
* function call.
*/
func = duk__nonbound_func_lookup(ctx, idx_func, &num_stack_args, &tv_func, call_flags);
if (func == NULL || !DUK_HOBJECT_IS_COMPFUNC(func)) {
DUK_DDD(DUK_DDDPRINT("final target is a lightfunc/nativefunc, cannot do ecma-to-ecma call"));
thr->ptr_curr_pc = entry_ptr_curr_pc;
return 0;
}
/* XXX: tv_func is not actually needed */
DUK_ASSERT(func != NULL);
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(func));
duk__coerce_effective_this_binding(thr, func, idx_func + 1);
DUK_DDD(DUK_DDDPRINT("effective 'this' binding is: %!T",
duk_get_tval(ctx, idx_func + 1)));
nargs = ((duk_hcompfunc *) func)->nargs;
nregs = ((duk_hcompfunc *) func)->nregs;
DUK_ASSERT(nregs >= nargs);
/* [ ... func this arg1 ... argN ] */
/*
* Preliminary activation record and valstack manipulation.
* The concrete actions depend on whether the we're dealing
* with a tail call (reuse an existing activation), a resume,
* or a normal call.
*
* The basic actions, in varying order, are:
*
* - Check stack size for call handling
* - Grow call stack if necessary (non-tail-calls)
* - Update current activation (idx_retval) if necessary
* (non-tail, non-resume calls)
* - Move start of args (idx_args) to valstack bottom
* (tail calls)
*
* Don't touch valstack_bottom or valstack_top yet so that Duktape API
* calls work normally.
*/
/* XXX: some overlapping code; cleanup */
use_tailcall = call_flags & DUK_CALL_FLAG_IS_TAILCALL;
#if !defined(DUK_USE_TAILCALL)
DUK_ASSERT(use_tailcall == 0); /* compiler ensures this */
#endif
if (use_tailcall) {
/* tailcall cannot be flagged to resume calls, and a
* previous frame must exist
*/
DUK_ASSERT(thr->callstack_top >= 1);
DUK_ASSERT((call_flags & DUK_CALL_FLAG_IS_RESUME) == 0);
act = thr->callstack + thr->callstack_top - 1;
if (act->flags & DUK_ACT_FLAG_PREVENT_YIELD) {
/* See: test-bug-tailcall-preventyield-assert.c. */
DUK_DDD(DUK_DDDPRINT("tail call prevented by current activation having DUK_ACT_FLAG_PREVENTYIELD"));
use_tailcall = 0;
} else if (DUK_HOBJECT_HAS_NOTAIL(func)) {
DUK_D(DUK_DPRINT("tail call prevented by function having a notail flag"));
use_tailcall = 0;
}
}
if (use_tailcall) {
duk_tval *tv1, *tv2;
duk_size_t cs_index;
duk_int_t i_stk; /* must be signed for loop structure */
duk_idx_t i_arg;
/*
* Tailcall handling
*
* Although the callstack entry is reused, we need to explicitly unwind
* the current activation (or simulate an unwind). In particular, the
* current activation must be closed, otherwise something like
* test-bug-reduce-judofyr.js results. Also catchstack needs be unwound
* because there may be non-error-catching label entries in valid tail calls.
*/
DUK_DDD(DUK_DDDPRINT("is tail call, reusing activation at callstack top, at index %ld",
(long) (thr->callstack_top - 1)));
/* 'act' already set above */
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(!DUK_HOBJECT_HAS_NATFUNC(func));
DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
DUK_ASSERT((act->flags & DUK_ACT_FLAG_PREVENT_YIELD) == 0);
/* Unwind catchstack entries referring to the callstack entry we're reusing */
cs_index = thr->callstack_top - 1;
DUK_ASSERT(thr->catchstack_top <= DUK_INT_MAX); /* catchstack limits */
for (i_stk = (duk_int_t) (thr->catchstack_top - 1); i_stk >= 0; i_stk--) {
duk_catcher *cat = thr->catchstack + i_stk;
if (cat->callstack_index != cs_index) {
/* 'i' is the first entry we'll keep */
break;
}
}
duk_hthread_catchstack_unwind(thr, i_stk + 1);
/* Unwind the topmost callstack entry before reusing it */
DUK_ASSERT(thr->callstack_top > 0);
duk_hthread_callstack_unwind(thr, thr->callstack_top - 1);
/* Then reuse the unwound activation; callstack was not shrunk so there is always space */
thr->callstack_top++;
DUK_ASSERT(thr->callstack_top <= thr->callstack_size);
act = thr->callstack + thr->callstack_top - 1;
/* Start filling in the activation */
act->func = func; /* don't want an intermediate exposed state with func == NULL */
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
act->prev_caller = NULL;
#endif
DUK_ASSERT(func != NULL);
DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
/* don't want an intermediate exposed state with invalid pc */
act->curr_pc = DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, (duk_hcompfunc *) func);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
act->prev_line = 0;
#endif
DUK_TVAL_SET_OBJECT(&act->tv_func, func); /* borrowed, no refcount */
#if defined(DUK_USE_REFERENCE_COUNTING)
DUK_HOBJECT_INCREF(thr, func);
act = thr->callstack + thr->callstack_top - 1; /* side effects (currently none though) */
#endif
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
#if defined(DUK_USE_TAILCALL)
#error incorrect options: tail calls enabled with function caller property
#endif
/* XXX: this doesn't actually work properly for tail calls, so
* tail calls are disabled when DUK_USE_NONSTD_FUNC_CALLER_PROPERTY
* is in use.
*/
duk__update_func_caller_prop(thr, func);
act = thr->callstack + thr->callstack_top - 1;
#endif
act->flags = (DUK_HOBJECT_HAS_STRICT(func) ?
DUK_ACT_FLAG_STRICT | DUK_ACT_FLAG_TAILCALLED :
DUK_ACT_FLAG_TAILCALLED);
DUK_ASSERT(DUK_ACT_GET_FUNC(act) == func); /* already updated */
DUK_ASSERT(act->var_env == NULL); /* already NULLed (by unwind) */
DUK_ASSERT(act->lex_env == NULL); /* already NULLed (by unwind) */
act->idx_bottom = entry_valstack_bottom_index; /* tail call -> reuse current "frame" */
DUK_ASSERT(nregs >= 0);
#if 0 /* topmost activation idx_retval is considered garbage, no need to init */
act->idx_retval = 0;
#endif
/*
* Manipulate valstack so that args are on the current bottom and the
* previous caller's 'this' binding (which is the value preceding the
* current bottom) is replaced with the new 'this' binding:
*
* [ ... this_old | (crud) func this_new arg1 ... argN ]
* --> [ ... this_new | arg1 ... argN ]
*
* For tail calling to work properly, the valstack bottom must not grow
* here; otherwise crud would accumulate on the valstack.
*/
tv1 = thr->valstack_bottom - 1;
tv2 = thr->valstack_bottom + idx_func + 1;
DUK_ASSERT(tv1 >= thr->valstack && tv1 < thr->valstack_top); /* tv1 is -below- valstack_bottom */
DUK_ASSERT(tv2 >= thr->valstack_bottom && tv2 < thr->valstack_top);
DUK_TVAL_SET_TVAL_UPDREF(thr, tv1, tv2); /* side effects */
for (i_arg = 0; i_arg < idx_args; i_arg++) {
/* XXX: block removal API primitive */
/* Note: 'func' is popped from valstack here, but it is
* already reachable from the activation.
*/
duk_remove(ctx, 0);
}
idx_func = 0; DUK_UNREF(idx_func); /* really 'not applicable' anymore, should not be referenced after this */
idx_args = 0;
/* [ ... this_new | arg1 ... argN ] */
} else {
DUK_DDD(DUK_DDDPRINT("not a tail call, pushing a new activation to callstack, to index %ld",
(long) (thr->callstack_top)));
duk_hthread_callstack_grow(thr);
if (call_flags & DUK_CALL_FLAG_IS_RESUME) {
DUK_DDD(DUK_DDDPRINT("is resume -> no update to current activation (may not even exist)"));
} else {
DUK_DDD(DUK_DDDPRINT("update to current activation idx_retval"));
DUK_ASSERT(thr->callstack_top < thr->callstack_size);
DUK_ASSERT(thr->callstack_top >= 1);
act = thr->callstack + thr->callstack_top - 1;
DUK_ASSERT(DUK_ACT_GET_FUNC(act) != NULL);
DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(act)));
act->idx_retval = entry_valstack_bottom_index + idx_func;
}
DUK_ASSERT(thr->callstack_top < thr->callstack_size);
act = thr->callstack + thr->callstack_top;
thr->callstack_top++;
DUK_ASSERT(thr->callstack_top <= thr->callstack_size);
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(!DUK_HOBJECT_HAS_NATFUNC(func));
DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
act->flags = (DUK_HOBJECT_HAS_STRICT(func) ?
DUK_ACT_FLAG_STRICT :
0);
act->func = func;
act->var_env = NULL;
act->lex_env = NULL;
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
act->prev_caller = NULL;
#endif
DUK_ASSERT(func != NULL);
DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
act->curr_pc = DUK_HCOMPFUNC_GET_CODE_BASE(thr->heap, (duk_hcompfunc *) func);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
act->prev_line = 0;
#endif
act->idx_bottom = entry_valstack_bottom_index + idx_args;
DUK_ASSERT(nregs >= 0);
#if 0 /* topmost activation idx_retval is considered garbage, no need to init */
act->idx_retval = 0;
#endif
DUK_TVAL_SET_OBJECT(&act->tv_func, func); /* borrowed, no refcount */
DUK_HOBJECT_INCREF(thr, func); /* act->func */
#if defined(DUK_USE_NONSTD_FUNC_CALLER_PROPERTY)
duk__update_func_caller_prop(thr, func);
act = thr->callstack + thr->callstack_top - 1;
#endif
}
/* [ ... func this arg1 ... argN ] (not tail call)
* [ this | arg1 ... argN ] (tail call)
*
* idx_args updated to match
*/
/*
* Environment record creation and 'arguments' object creation.
* Named function expression name binding is handled by the
* compiler; the compiled function's parent env will contain
* the (immutable) binding already.
*
* Delayed creation (on demand) is handled in duk_js_var.c.
*/
/* XXX: unify handling with native call. */
DUK_ASSERT(!DUK_HOBJECT_HAS_BOUNDFUNC(func)); /* bound function chain has already been resolved */
if (!DUK_HOBJECT_HAS_NEWENV(func)) {
/* use existing env (e.g. for non-strict eval); cannot have
* an own 'arguments' object (but can refer to the existing one)
*/
duk__handle_oldenv_for_call(thr, func, act);
DUK_ASSERT(act->lex_env != NULL);
DUK_ASSERT(act->var_env != NULL);
goto env_done;
}
DUK_ASSERT(DUK_HOBJECT_HAS_NEWENV(func));
if (!DUK_HOBJECT_HAS_CREATEARGS(func)) {
/* no need to create environment record now; leave as NULL */
DUK_ASSERT(act->lex_env == NULL);
DUK_ASSERT(act->var_env == NULL);
goto env_done;
}
/* third arg: absolute index (to entire valstack) of idx_bottom of new activation */
env = duk_create_activation_environment_record(thr, func, act->idx_bottom);
DUK_ASSERT(env != NULL);
/* [ ... arg1 ... argN envobj ] */
/* original input stack before nargs/nregs handling must be
* intact for 'arguments' object
*/
DUK_ASSERT(DUK_HOBJECT_HAS_CREATEARGS(func));
duk__handle_createargs_for_call(thr, func, env, num_stack_args);
/* [ ... arg1 ... argN envobj ] */
act = thr->callstack + thr->callstack_top - 1;
act->lex_env = env;
act->var_env = env;
DUK_HOBJECT_INCREF(thr, act->lex_env);
DUK_HOBJECT_INCREF(thr, act->var_env);
duk_pop(ctx);
env_done:
/* [ ... arg1 ... argN ] */
/*
* Setup value stack: clamp to 'nargs', fill up to 'nregs'
*/
duk__adjust_valstack_and_top(thr,
num_stack_args,
idx_args,
nregs,
nargs,
func);
/*
* Shift to new valstack_bottom.
*/
thr->valstack_bottom = thr->valstack_bottom + idx_args;
/* keep current valstack_top */
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
/*
* Return to bytecode executor, which will resume execution from
* the topmost activation.
*/
return 1;
}