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cosmopolitan/third_party/duktape/duk_js_call.c

2934 lines
105 KiB
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Initial import
2020-06-15 14:18:57 +00:00
/*
* Call handling.
*
* duk_handle_call_unprotected():
*
* - Unprotected call to ECMAScript or Duktape/C function, from native
* code or bytecode executor.
*
* - Also handles Ecma-to-Ecma calls which reuses a currently running
* executor instance to avoid native recursion. Call setup is done
* normally, but just before calling the bytecode executor a special
* return code is used to indicate that a calling executor is reused.
*
* - Also handles tailcalls, i.e. reuse of current duk_activation.
*
* - Also handles setup for initial Duktape.Thread.resume().
*
* duk_handle_safe_call():
*
* - Protected C call within current activation.
*
* 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 and can cause compiler or compiler version specific
* difficult to replicate issues.
*
* See 'execution.rst'.
*/
#include "third_party/duktape/duk_internal.h"
/* XXX: heap->error_not_allowed for success path too? */
/*
* Limit check helpers.
*/
/* Check native stack space if DUK_USE_NATIVE_STACK_CHECK() defined. */
DUK_INTERNAL void duk_native_stack_check(duk_hthread *thr) {
#if defined(DUK_USE_NATIVE_STACK_CHECK)
if (DUK_USE_NATIVE_STACK_CHECK() != 0) {
DUK_ERROR_RANGE(thr, DUK_STR_NATIVE_STACK_LIMIT);
}
#else
DUK_UNREF(thr);
#endif
}
/* Allow headroom for calls during error augmentation (see GH-191).
* We allow space for 10 additional recursions, with one extra
* for, e.g. a print() call at the deepest level, and an extra
* +1 for protected call wrapping.
*/
#define DUK__AUGMENT_CALL_RELAX_COUNT (10 + 2)
/* Stack space required by call handling entry. */
#define DUK__CALL_HANDLING_REQUIRE_STACK 8
DUK_LOCAL DUK_NOINLINE void duk__call_c_recursion_limit_check_slowpath(duk_hthread *thr) {
/* When augmenting an error, the effective limit is a bit higher.
* Check for it only if the fast path check fails.
*/
#if defined(DUK_USE_AUGMENT_ERROR_THROW) || defined(DUK_USE_AUGMENT_ERROR_CREATE)
if (thr->heap->augmenting_error) {
if (thr->heap->call_recursion_depth < thr->heap->call_recursion_limit + DUK__AUGMENT_CALL_RELAX_COUNT) {
DUK_D(DUK_DPRINT("C recursion limit reached but augmenting error and within relaxed limit"));
return;
}
}
#endif
DUK_D(DUK_DPRINT("call prevented because C recursion limit reached"));
DUK_ERROR_RANGE(thr, DUK_STR_NATIVE_STACK_LIMIT);
DUK_WO_NORETURN(return;);
}
DUK_LOCAL DUK_ALWAYS_INLINE void duk__call_c_recursion_limit_check(duk_hthread *thr) {
DUK_ASSERT(thr->heap->call_recursion_depth >= 0);
DUK_ASSERT(thr->heap->call_recursion_depth <= thr->heap->call_recursion_limit);
duk_native_stack_check(thr);
/* This check is forcibly inlined because it's very cheap and almost
* always passes. The slow path is forcibly noinline.
*/
if (DUK_LIKELY(thr->heap->call_recursion_depth < thr->heap->call_recursion_limit)) {
return;
}
duk__call_c_recursion_limit_check_slowpath(thr);
}
DUK_LOCAL DUK_NOINLINE void duk__call_callstack_limit_check_slowpath(duk_hthread *thr) {
/* When augmenting an error, the effective limit is a bit higher.
* Check for it only if the fast path check fails.
*/
#if defined(DUK_USE_AUGMENT_ERROR_THROW) || defined(DUK_USE_AUGMENT_ERROR_CREATE)
if (thr->heap->augmenting_error) {
if (thr->callstack_top < DUK_USE_CALLSTACK_LIMIT + DUK__AUGMENT_CALL_RELAX_COUNT) {
DUK_D(DUK_DPRINT("call stack limit reached but augmenting error and within relaxed limit"));
return;
}
}
#endif
/* 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_D(DUK_DPRINT("call prevented because call stack limit reached"));
DUK_ERROR_RANGE(thr, DUK_STR_CALLSTACK_LIMIT);
DUK_WO_NORETURN(return;);
}
DUK_LOCAL DUK_ALWAYS_INLINE void duk__call_callstack_limit_check(duk_hthread *thr) {
/* This check is forcibly inlined because it's very cheap and almost
* always passes. The slow path is forcibly noinline.
*/
if (DUK_LIKELY(thr->callstack_top < DUK_USE_CALLSTACK_LIMIT)) {
return;
}
duk__call_callstack_limit_check_slowpath(thr);
}
/*
* 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_args) {
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_idx_t num_stack_args;
duk_bool_t need_map;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(func != NULL);
DUK_ASSERT(DUK_HOBJECT_IS_NONBOUND_FUNCTION(func));
DUK_ASSERT(varenv != NULL);
/* [ ... func this arg1(@idx_args) ... argN envobj ]
* [ arg1(@idx_args) ... argN envobj ] (for tailcalls)
*/
need_map = 0;
i_argbase = idx_args;
num_stack_args = duk_get_top(thr) - i_argbase - 1;
DUK_ASSERT(i_argbase >= 0);
DUK_ASSERT(num_stack_args >= 0);
formals = (duk_hobject *) duk_hobject_get_formals(thr, (duk_hobject *) func);
if (formals) {
n_formals = (duk_idx_t) ((duk_harray *) formals)->length;
duk_push_hobject(thr, formals);
} else {
/* This shouldn't happen without tampering of internal
* properties: if a function accesses 'arguments', _Formals
* is kept. Check for the case anyway in case internal
* properties have been modified manually.
*/
DUK_D(DUK_DPRINT("_Formals is undefined when creating arguments, use n_formals == 0"));
n_formals = 0;
duk_push_undefined(thr);
}
i_formals = duk_require_top_index(thr);
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' (bare)
* - 'mappedNames' object: temporary value used during construction (bare)
*/
arg = duk_push_object_helper(thr,
DUK_HOBJECT_FLAG_EXTENSIBLE |
DUK_HOBJECT_FLAG_FASTREFS |
DUK_HOBJECT_FLAG_ARRAY_PART |
DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_ARGUMENTS),
DUK_BIDX_OBJECT_PROTOTYPE);
DUK_ASSERT(arg != NULL);
(void) duk_push_object_helper(thr,
DUK_HOBJECT_FLAG_EXTENSIBLE |
DUK_HOBJECT_FLAG_FASTREFS |
DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
-1); /* no prototype */
(void) duk_push_object_helper(thr,
DUK_HOBJECT_FLAG_EXTENSIBLE |
DUK_HOBJECT_FLAG_FASTREFS |
DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_OBJECT),
-1); /* no prototype */
i_arg = duk_get_top(thr) - 3;
i_map = i_arg + 1;
i_mappednames = i_arg + 2;
DUK_ASSERT(!duk_is_bare_object(thr, -3)); /* arguments */
DUK_ASSERT(duk_is_bare_object(thr, -2)); /* map */
DUK_ASSERT(duk_is_bare_object(thr, -1)); /* mappedNames */
/* [ ... 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(thr, i_arg),
(long) i_map, (duk_heaphdr *) duk_get_hobject(thr, i_map),
(long) i_mappednames, (duk_heaphdr *) duk_get_hobject(thr, i_mappednames)));
/*
* Init arguments properties, map, etc.
*/
duk_push_int(thr, num_stack_args);
duk_xdef_prop_stridx(thr, 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(thr, i_argbase + idx);
duk_xdef_prop_index_wec(thr, 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(thr, i_formals, (duk_uarridx_t) idx);
DUK_ASSERT(duk_is_string(thr, -1));
duk_dup_top(thr); /* [ ... name name ] */
if (!duk_has_prop(thr, 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(thr, -1),
(long) idx));
duk_dup_top(thr); /* name */
(void) duk_push_uint_to_hstring(thr, (duk_uint_t) idx); /* index */
duk_xdef_prop_wec(thr, i_mappednames); /* out of spec, must be configurable */
DUK_DDD(DUK_DDDPRINT("set map[%ld]=%s",
(long) idx,
duk_get_string(thr, -1)));
duk_dup_top(thr); /* name */
duk_xdef_prop_index_wec(thr, i_map, (duk_uarridx_t) idx); /* out of spec, must be configurable */
} else {
/* duk_has_prop() popped the second 'name' */
}
/* [ ... name ] */
duk_pop(thr); /* 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(thr, i_map);
duk_xdef_prop_stridx(thr, 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(thr, varenv);
duk_xdef_prop_stridx(thr, 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"));
/* In ES2017 .caller is no longer set at all. */
duk_xdef_prop_stridx_thrower(thr, i_arg, DUK_STRIDX_CALLEE);
} else {
DUK_DDD(DUK_DDDPRINT("non-strict function, setting callee to actual value"));
duk_push_hobject(thr, func);
duk_xdef_prop_stridx(thr, 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(thr, i_arg),
(long) i_map, (duk_heaphdr *) duk_get_hobject(thr, i_map),
(long) i_mappednames, (duk_heaphdr *) duk_get_hobject(thr, i_mappednames)));
/* [ args(n) envobj formals arguments map mappednames ] */
duk_pop_2(thr);
duk_remove_m2(thr);
/* [ args(n) envobj arguments ] */
}
/* Helper for creating the arguments object and adding it to the env record
* on top of the value stack.
*/
DUK_LOCAL void duk__handle_createargs_for_call(duk_hthread *thr,
duk_hobject *func,
duk_hobject *env,
duk_idx_t idx_args) {
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));
/* [ ... arg1 ... argN envobj ] */
duk__create_arguments_object(thr,
func,
env,
idx_args);
/* [ ... arg1 ... argN envobj argobj ] */
duk_xdef_prop_stridx_short(thr,
-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 ] */
}
/*
* Helpers for constructor call handling.
*
* There are two [[Construct]] operations in the specification:
*
* - E5 Section 13.2.2: for Function objects
* - E5 Section 15.3.4.5.2: for "bound" Function objects
*
* The chain of bound functions is resolved in Section 15.3.4.5.2,
* with arguments "piling up" until the [[Construct]] internal
* method is called on the final, actual Function object. Note
* that the "prototype" property is looked up *only* from the
* final object, *before* calling the constructor.
*
* Since Duktape 2.2 bound functions are represented with the
* duk_hboundfunc internal type, and bound function chains are
* collapsed when a bound function is created. As a result, the
* direct target of a duk_hboundfunc is always non-bound and the
* this/argument lists have been resolved.
*
* When constructing new Array instances, an unnecessary object is
* created and discarded now: the standard [[Construct]] creates an
* object, and calls the Array constructor. The Array constructor
* returns an Array instance, which is used as the result value for
* the "new" operation; the object created before the Array constructor
* call is discarded.
*
* This would be easy to fix, e.g. by knowing that the Array constructor
* will always create a replacement object and skip creating the fallback
* object in that case.
*/
/* Update default instance prototype for constructor call. */
DUK_LOCAL void duk__update_default_instance_proto(duk_hthread *thr, duk_idx_t idx_func) {
duk_hobject *proto;
duk_hobject *fallback;
DUK_ASSERT(duk_is_constructable(thr, idx_func));
duk_get_prop_stridx_short(thr, idx_func, DUK_STRIDX_PROTOTYPE);
proto = duk_get_hobject(thr, -1);
if (proto == NULL) {
DUK_DDD(DUK_DDDPRINT("constructor has no 'prototype' property, or value not an object "
"-> leave standard Object prototype as fallback prototype"));
} else {
DUK_DDD(DUK_DDDPRINT("constructor has 'prototype' property with object value "
"-> set fallback prototype to that value: %!iO", (duk_heaphdr *) proto));
/* Original fallback (default instance) is untouched when
* resolving bound functions etc.
*/
fallback = duk_known_hobject(thr, idx_func + 1);
DUK_ASSERT(fallback != NULL);
DUK_HOBJECT_SET_PROTOTYPE_UPDREF(thr, fallback, proto);
}
duk_pop(thr);
}
/* Postprocess: return value special handling, error augmentation. */
DUK_INTERNAL void duk_call_construct_postprocess(duk_hthread *thr, duk_small_uint_t proxy_invariant) {
/* Use either fallback (default instance) or retval depending
* on retval type. Needs to be called before unwind because
* the default instance is read from the current (immutable)
* 'this' binding.
*
* For Proxy 'construct' calls the return value must be an
* Object (we accept object-like values like buffers and
* lightfuncs too). If not, TypeError.
*/
if (duk_check_type_mask(thr, -1, DUK_TYPE_MASK_OBJECT |
DUK_TYPE_MASK_BUFFER |
DUK_TYPE_MASK_LIGHTFUNC)) {
DUK_DDD(DUK_DDDPRINT("replacement value"));
} else {
if (DUK_UNLIKELY(proxy_invariant != 0U)) {
/* Proxy 'construct' return value invariant violated. */
DUK_ERROR_TYPE_INVALID_TRAP_RESULT(thr);
DUK_WO_NORETURN(return;);
}
/* XXX: direct value stack access */
duk_pop(thr);
duk_push_this(thr);
}
#if defined(DUK_USE_AUGMENT_ERROR_CREATE)
/* Augment created errors upon creation, not when they are thrown or
* rethrown. __FILE__ and __LINE__ are not desirable here; the call
* stack reflects the caller which is correct. Skip topmost, unwound
* activation when creating a traceback. If thr->ptr_curr_pc was !=
* NULL we'd need to sync the current PC so that the traceback comes
* out right; however it is always synced here so just assert for it.
*/
DUK_ASSERT(thr->ptr_curr_pc == NULL);
duk_err_augment_error_create(thr, thr, NULL, 0, DUK_AUGMENT_FLAG_NOBLAME_FILELINE |
DUK_AUGMENT_FLAG_SKIP_ONE);
#endif
}
/*
* Helper for handling a bound function when a call is being made.
*
* Assumes that bound function chains have been "collapsed" so that either
* the target is non-bound or there is one bound function that points to a
* nonbound target.
*
* Prepends the bound arguments to the value stack (at idx_func + 2).
* 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]].
*/
DUK_LOCAL void duk__handle_bound_chain_for_call(duk_hthread *thr,
duk_idx_t idx_func,
duk_bool_t is_constructor_call) {
duk_tval *tv_func;
duk_hobject *func;
duk_idx_t len;
DUK_ASSERT(thr != NULL);
/* On entry, item at idx_func is a bound, non-lightweight function,
* but we don't rely on that below.
*/
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
tv_func = duk_require_tval(thr, idx_func);
DUK_ASSERT(tv_func != NULL);
if (DUK_TVAL_IS_OBJECT(tv_func)) {
func = DUK_TVAL_GET_OBJECT(tv_func);
/* XXX: separate helper function, out of fast path? */
if (DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
duk_hboundfunc *h_bound;
duk_tval *tv_args;
duk_tval *tv_gap;
h_bound = (duk_hboundfunc *) (void *) func;
tv_args = h_bound->args;
len = h_bound->nargs;
DUK_ASSERT(len == 0 || tv_args != NULL);
DUK_DDD(DUK_DDDPRINT("bound function encountered, ptr=%p: %!T",
(void *) DUK_TVAL_GET_OBJECT(tv_func), 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 {
/* XXX: duk_replace_tval */
duk_push_tval(thr, &h_bound->this_binding);
duk_replace(thr, idx_func + 1); /* idx_this = idx_func + 1 */
}
/* [ ... func this arg1 ... argN ] */
duk_require_stack(thr, len);
tv_gap = duk_reserve_gap(thr, idx_func + 2, len);
duk_copy_tvals_incref(thr, tv_gap, tv_args, (duk_size_t) len);
/* [ ... func this <bound args> arg1 ... argN ] */
duk_push_tval(thr, &h_bound->target);
duk_replace(thr, idx_func); /* replace in stack */
DUK_DDD(DUK_DDDPRINT("bound function handled, idx_func=%ld, curr func=%!T",
(long) idx_func, duk_get_tval(thr, idx_func)));
}
} else if (DUK_TVAL_IS_LIGHTFUNC(tv_func)) {
/* Lightweight function: never bound, so terminate. */
;
} else {
/* Shouldn't happen, so ugly error is enough. */
DUK_ERROR_INTERNAL(thr);
DUK_WO_NORETURN(return;);
}
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
DUK_DDD(DUK_DDDPRINT("final non-bound function is: %!T", duk_get_tval(thr, idx_func)));
#if defined(DUK_USE_ASSERTIONS)
tv_func = duk_require_tval(thr, 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) ||
DUK_HOBJECT_IS_PROXY(func));
}
#endif
}
/*
* Helper for inline handling of .call(), .apply(), and .construct().
*/
DUK_LOCAL duk_bool_t duk__handle_specialfuncs_for_call(duk_hthread *thr, duk_idx_t idx_func, duk_hobject *func, duk_small_uint_t *call_flags, duk_bool_t first) {
#if defined(DUK_USE_ASSERTIONS)
duk_c_function natfunc;
#endif
duk_tval *tv_args;
DUK_ASSERT(func != NULL);
DUK_ASSERT((*call_flags & DUK_CALL_FLAG_CONSTRUCT) == 0); /* Caller. */
#if defined(DUK_USE_ASSERTIONS)
natfunc = ((duk_hnatfunc *) func)->func;
DUK_ASSERT(natfunc != NULL);
#endif
/* On every round of function resolution at least target function and
* 'this' binding are set. We can assume that here, and must guarantee
* it on exit. Value stack reserve is extended for bound function and
* .apply() unpacking so we don't need to extend it here when we need a
* few slots.
*/
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
/* Handle native 'eval' specially. A direct eval check is only made
* for the first resolution attempt; e.g. a bound eval call is -not-
* a direct eval call.
*/
if (DUK_UNLIKELY(((duk_hnatfunc *) func)->magic == 15)) {
/* For now no special handling except for direct eval
* detection.
*/
DUK_ASSERT(((duk_hnatfunc *) func)->func == duk_bi_global_object_eval);
if (first && (*call_flags & DUK_CALL_FLAG_CALLED_AS_EVAL)) {
*call_flags = (*call_flags & ~DUK_CALL_FLAG_CALLED_AS_EVAL) | DUK_CALL_FLAG_DIRECT_EVAL;
}
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
return 1; /* stop resolving */
}
/* Handle special functions based on the DUK_HOBJECT_FLAG_SPECIAL_CALL
* flag; their magic value is used for switch-case.
*
* NOTE: duk_unpack_array_like() reserves value stack space
* for the result values (unlike most other value stack calls).
*/
switch (((duk_hnatfunc *) func)->magic) {
case 0: { /* 0=Function.prototype.call() */
/* Value stack:
* idx_func + 0: Function.prototype.call() [removed]
* idx_func + 1: this binding for .call (target function)
* idx_func + 2: 1st argument to .call, desired 'this' binding
* idx_func + 3: 2nd argument to .call, desired 1st argument for ultimate target
* ...
*
* Remove idx_func + 0 to get:
* idx_func + 0: target function
* idx_func + 1: this binding
* idx_func + 2: call arguments
* ...
*/
DUK_ASSERT(natfunc == duk_bi_function_prototype_call);
duk_remove_unsafe(thr, idx_func);
tv_args = thr->valstack_bottom + idx_func + 2;
if (thr->valstack_top < tv_args) {
DUK_ASSERT(tv_args <= thr->valstack_end);
thr->valstack_top = tv_args; /* at least target function and 'this' binding present */
}
break;
}
case 1: { /* 1=Function.prototype.apply() */
/* Value stack:
* idx_func + 0: Function.prototype.apply() [removed]
* idx_func + 1: this binding for .apply (target function)
* idx_func + 2: 1st argument to .apply, desired 'this' binding
* idx_func + 3: 2nd argument to .apply, argArray
* [anything after this MUST be ignored]
*
* Remove idx_func + 0 and unpack the argArray to get:
* idx_func + 0: target function
* idx_func + 1: this binding
* idx_func + 2: call arguments
* ...
*/
DUK_ASSERT(natfunc == duk_bi_function_prototype_apply);
duk_remove_unsafe(thr, idx_func);
goto apply_shared;
}
#if defined(DUK_USE_REFLECT_BUILTIN)
case 2: { /* 2=Reflect.apply() */
/* Value stack:
* idx_func + 0: Reflect.apply() [removed]
* idx_func + 1: this binding for .apply (ignored, usually Reflect) [removed]
* idx_func + 2: 1st argument to .apply, target function
* idx_func + 3: 2nd argument to .apply, desired 'this' binding
* idx_func + 4: 3rd argument to .apply, argArray
* [anything after this MUST be ignored]
*
* Remove idx_func + 0 and idx_func + 1, and unpack the argArray to get:
* idx_func + 0: target function
* idx_func + 1: this binding
* idx_func + 2: call arguments
* ...
*/
DUK_ASSERT(natfunc == duk_bi_reflect_apply);
duk_remove_n_unsafe(thr, idx_func, 2);
goto apply_shared;
}
case 3: { /* 3=Reflect.construct() */
/* Value stack:
* idx_func + 0: Reflect.construct() [removed]
* idx_func + 1: this binding for .construct (ignored, usually Reflect) [removed]
* idx_func + 2: 1st argument to .construct, target function
* idx_func + 3: 2nd argument to .construct, argArray
* idx_func + 4: 3rd argument to .construct, newTarget
* [anything after this MUST be ignored]
*
* Remove idx_func + 0 and idx_func + 1, unpack the argArray,
* and insert default instance (prototype not yet updated), to get:
* idx_func + 0: target function
* idx_func + 1: this binding (default instance)
* idx_func + 2: constructor call arguments
* ...
*
* Call flags must be updated to reflect the fact that we're
* now dealing with a constructor call, and e.g. the 'this'
* binding cannot be overwritten if the target is bound.
*
* newTarget is checked but not yet passed onwards.
*/
duk_idx_t top;
DUK_ASSERT(natfunc == duk_bi_reflect_construct);
*call_flags |= DUK_CALL_FLAG_CONSTRUCT;
duk_remove_n_unsafe(thr, idx_func, 2);
top = duk_get_top(thr);
if (!duk_is_constructable(thr, idx_func)) {
/* Target constructability must be checked before
* unpacking argArray (which may cause side effects).
* Just return; caller will throw the error.
*/
duk_set_top_unsafe(thr, idx_func + 2); /* satisfy asserts */
break;
}
duk_push_object(thr);
duk_insert(thr, idx_func + 1); /* default instance */
/* [ ... func default_instance argArray newTarget? ] */
top = duk_get_top(thr);
if (top < idx_func + 3) {
/* argArray is a mandatory argument for Reflect.construct(). */
DUK_ERROR_TYPE_INVALID_ARGS(thr);
DUK_WO_NORETURN(return 0;);
}
if (top > idx_func + 3) {
if (!duk_strict_equals(thr, idx_func, idx_func + 3)) {
/* XXX: [[Construct]] newTarget currently unsupported */
DUK_ERROR_UNSUPPORTED(thr);
DUK_WO_NORETURN(return 0;);
}
duk_set_top_unsafe(thr, idx_func + 3); /* remove any args beyond argArray */
}
DUK_ASSERT(duk_get_top(thr) == idx_func + 3);
DUK_ASSERT(duk_is_valid_index(thr, idx_func + 2));
(void) duk_unpack_array_like(thr, idx_func + 2); /* XXX: should also remove target to be symmetric with duk_pack()? */
duk_remove(thr, idx_func + 2);
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
break;
}
#endif /* DUK_USE_REFLECT_BUILTIN */
default: {
DUK_ASSERT(0);
DUK_UNREACHABLE();
}
}
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
return 0; /* keep resolving */
apply_shared:
tv_args = thr->valstack_bottom + idx_func + 2;
if (thr->valstack_top <= tv_args) {
DUK_ASSERT(tv_args <= thr->valstack_end);
thr->valstack_top = tv_args; /* at least target func and 'this' binding present */
/* No need to check for argArray. */
} else {
DUK_ASSERT(duk_get_top(thr) >= idx_func + 3); /* idx_func + 2 covered above */
if (thr->valstack_top > tv_args + 1) {
duk_set_top_unsafe(thr, idx_func + 3); /* remove any args beyond argArray */
}
DUK_ASSERT(duk_is_valid_index(thr, idx_func + 2));
if (!duk_is_callable(thr, idx_func)) {
/* Avoid unpack side effects if the target isn't callable.
* Calling code will throw the actual error.
*/
} else {
(void) duk_unpack_array_like(thr, idx_func + 2);
duk_remove(thr, idx_func + 2);
}
}
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
return 0; /* keep resolving */
}
/*
* Helper for Proxy handling.
*/
#if defined(DUK_USE_ES6_PROXY)
DUK_LOCAL void duk__handle_proxy_for_call(duk_hthread *thr, duk_idx_t idx_func, duk_hproxy *h_proxy, duk_small_uint_t *call_flags) {
duk_bool_t rc;
/* Value stack:
* idx_func + 0: Proxy object
* idx_func + 1: this binding for call
* idx_func + 2: 1st argument for call
* idx_func + 3: 2nd argument for call
* ...
*
* If Proxy doesn't have a trap for the call ('apply' or 'construct'),
* replace Proxy object with target object.
*
* If we're dealing with a normal call and the Proxy has an 'apply'
* trap, manipulate value stack to:
*
* idx_func + 0: trap
* idx_func + 1: Proxy's handler
* idx_func + 2: Proxy's target
* idx_func + 3: this binding for call (from idx_func + 1)
* idx_func + 4: call arguments packed to an array
*
* If we're dealing with a constructor call and the Proxy has a
* 'construct' trap, manipulate value stack to:
*
* idx_func + 0: trap
* idx_func + 1: Proxy's handler
* idx_func + 2: Proxy's target
* idx_func + 3: call arguments packed to an array
* idx_func + 4: newTarget == Proxy object here
*
* As we don't yet have proper newTarget support, the newTarget at
* idx_func + 3 is just the original constructor being called, i.e.
* the Proxy object (not the target). Note that the default instance
* (original 'this' binding) is dropped and ignored.
*/
duk_push_hobject(thr, h_proxy->handler);
rc = duk_get_prop_stridx_short(thr, -1, (*call_flags & DUK_CALL_FLAG_CONSTRUCT) ? DUK_STRIDX_CONSTRUCT : DUK_STRIDX_APPLY);
if (rc == 0) {
/* Not found, continue to target. If this is a construct
* call, update default instance prototype using the Proxy,
* not the target.
*/
if (*call_flags & DUK_CALL_FLAG_CONSTRUCT) {
if (!(*call_flags & DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED)) {
*call_flags |= DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED;
duk__update_default_instance_proto(thr, idx_func);
}
}
duk_pop_2(thr);
duk_push_hobject(thr, h_proxy->target);
duk_replace(thr, idx_func);
return;
}
/* Here we must be careful not to replace idx_func while
* h_proxy is still needed, otherwise h_proxy may become
* dangling. This could be improved e.g. using a
* duk_pack_slice() with a freeform slice.
*/
/* Here:
* idx_func + 0: Proxy object
* idx_func + 1: this binding for call
* idx_func + 2: 1st argument for call
* idx_func + 3: 2nd argument for call
* ...
* idx_func + N: handler
* idx_func + N + 1: trap
*/
duk_insert(thr, idx_func + 1);
duk_insert(thr, idx_func + 2);
duk_push_hobject(thr, h_proxy->target);
duk_insert(thr, idx_func + 3);
duk_pack(thr, duk_get_top(thr) - (idx_func + 5));
DUK_ASSERT(!duk_is_bare_object(thr, -1));
/* Here:
* idx_func + 0: Proxy object
* idx_func + 1: trap
* idx_func + 2: Proxy's handler
* idx_func + 3: Proxy's target
* idx_func + 4: this binding for call
* idx_func + 5: arguments array
*/
DUK_ASSERT(duk_get_top(thr) == idx_func + 6);
if (*call_flags & DUK_CALL_FLAG_CONSTRUCT) {
*call_flags |= DUK_CALL_FLAG_CONSTRUCT_PROXY; /* Enable 'construct' trap return invariant check. */
*call_flags &= ~(DUK_CALL_FLAG_CONSTRUCT); /* Resume as non-constructor call to the trap. */
/* 'apply' args: target, thisArg, argArray
* 'construct' args: target, argArray, newTarget
*/
duk_remove(thr, idx_func + 4);
duk_push_hobject(thr, (duk_hobject *) h_proxy);
}
/* Finalize value stack layout by removing Proxy reference. */
duk_remove(thr, idx_func);
h_proxy = NULL; /* invalidated */
DUK_ASSERT(duk_get_top(thr) == idx_func + 5);
}
#endif /* DUK_USE_ES6_PROXY */
/*
* 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_hcompfunc *f;
duk_hobject *h_lex;
duk_hobject *h_var;
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));
DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(func));
DUK_UNREF(thr);
f = (duk_hcompfunc *) func;
h_lex = DUK_HCOMPFUNC_GET_LEXENV(thr->heap, f);
h_var = DUK_HCOMPFUNC_GET_VARENV(thr->heap, f);
DUK_ASSERT(h_lex != NULL); /* Always true for closures (not for templates) */
DUK_ASSERT(h_var != NULL);
act->lex_env = h_lex;
act->var_env = h_var;
DUK_HOBJECT_INCREF(thr, h_lex);
DUK_HOBJECT_INCREF(thr, h_var);
}
/*
* 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;
}
DUK_ASSERT(thr->callstack_top > 0);
act_callee = thr->callstack_curr;
DUK_ASSERT(act_callee != NULL);
act_caller = (thr->callstack_top >= 2 ? act_callee->parent : NULL);
/* XXX: check .caller writability? */
/* Backup 'caller' property and update its value. */
tv_caller = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, func, DUK_STRIDX_CALLER);
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 != NULL) {
/* 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 != NULL) {
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 != NULL && 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 */
/*
* Shared helpers for resolving the final, non-bound target function of the
* call and the effective 'this' binding. Resolves bound functions and
* applies .call(), .apply(), and .construct() inline.
*
* Proxy traps are also handled inline so that if the target is a Proxy with
* a 'call' or 'construct' trap, the trap handler is called with a modified
* argument list.
*
* Once the bound function / .call() / .apply() / .construct() sequence has
* been resolved, the value at idx_func + 1 may need coercion described in
* E5 Section 10.4.3.
*
* A call that begins as a non-constructor call may be converted into a
* constructor call during the resolution process if Reflect.construct()
* is invoked. This is handled by updating the caller's call_flags.
*
* 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
*
* The 'this' coercion may cause a recursive function call with arbitrary
* side effects, because ToObject() may be called.
*/
DUK_LOCAL DUK_INLINE void duk__coerce_nonstrict_this_binding(duk_hthread *thr, duk_idx_t idx_this) {
duk_tval *tv_this;
duk_hobject *obj_global;
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 non-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(thr, idx_this); /* may have side effects */
break;
}
}
DUK_LOCAL DUK_ALWAYS_INLINE duk_bool_t duk__resolve_target_fastpath_check(duk_hthread *thr, duk_idx_t idx_func, duk_hobject **out_func, duk_small_uint_t call_flags) {
#if defined(DUK_USE_PREFER_SIZE)
DUK_UNREF(thr);
DUK_UNREF(idx_func);
DUK_UNREF(out_func);
DUK_UNREF(call_flags);
#else /* DUK_USE_PREFER_SIZE */
duk_tval *tv_func;
duk_hobject *func;
if (DUK_UNLIKELY(call_flags & DUK_CALL_FLAG_CONSTRUCT)) {
return 0;
}
tv_func = DUK_GET_TVAL_POSIDX(thr, idx_func);
DUK_ASSERT(tv_func != NULL);
if (DUK_LIKELY(DUK_TVAL_IS_OBJECT(tv_func))) {
func = DUK_TVAL_GET_OBJECT(tv_func);
if (DUK_HOBJECT_IS_CALLABLE(func) &&
!DUK_HOBJECT_HAS_BOUNDFUNC(func) &&
!DUK_HOBJECT_HAS_SPECIAL_CALL(func)) {
*out_func = func;
if (DUK_HOBJECT_HAS_STRICT(func)) {
/* Strict function: no 'this' coercion. */
return 1;
}
duk__coerce_nonstrict_this_binding(thr, idx_func + 1);
return 1;
}
} else if (DUK_TVAL_IS_LIGHTFUNC(tv_func)) {
*out_func = NULL;
/* Lightfuncs are considered strict, so 'this' binding is
* used as is. They're never bound, always constructable,
* and never special functions.
*/
return 1;
}
#endif /* DUK_USE_PREFER_SIZE */
return 0; /* let slow path deal with it */
}
DUK_LOCAL duk_hobject *duk__resolve_target_func_and_this_binding(duk_hthread *thr,
duk_idx_t idx_func,
duk_small_uint_t *call_flags) {
duk_tval *tv_func;
duk_hobject *func;
duk_bool_t first;
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
for (first = 1;; first = 0) {
DUK_ASSERT(duk_get_top(thr) >= idx_func + 2);
tv_func = DUK_GET_TVAL_POSIDX(thr, idx_func);
DUK_ASSERT(tv_func != NULL);
DUK_DD(DUK_DDPRINT("target func: %!iT", tv_func));
if (DUK_TVAL_IS_OBJECT(tv_func)) {
func = DUK_TVAL_GET_OBJECT(tv_func);
if (*call_flags & DUK_CALL_FLAG_CONSTRUCT) {
if (DUK_UNLIKELY(!DUK_HOBJECT_HAS_CONSTRUCTABLE(func))) {
goto not_constructable;
}
} else {
if (DUK_UNLIKELY(!DUK_HOBJECT_IS_CALLABLE(func))) {
goto not_callable;
}
}
if (DUK_LIKELY(!DUK_HOBJECT_HAS_BOUNDFUNC(func) &&
!DUK_HOBJECT_HAS_SPECIAL_CALL(func) &&
!DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(func))) {
/* Common case, so test for using a single bitfield test.
* Break out to handle this coercion etc.
*/
break;
}
/* XXX: could set specialcall for boundfuncs too, simplify check above */
if (DUK_HOBJECT_HAS_BOUNDFUNC(func)) {
DUK_ASSERT(!DUK_HOBJECT_HAS_SPECIAL_CALL(func));
DUK_ASSERT(!DUK_HOBJECT_IS_NATFUNC(func));
/* Callable/constructable flags are the same
* for the bound function and its target, so
* we don't need to check them here, we can
* check them from the target only.
*/
duk__handle_bound_chain_for_call(thr, idx_func, *call_flags & DUK_CALL_FLAG_CONSTRUCT);
DUK_ASSERT(DUK_TVAL_IS_OBJECT(duk_require_tval(thr, idx_func)) ||
DUK_TVAL_IS_LIGHTFUNC(duk_require_tval(thr, idx_func)));
} else {
DUK_ASSERT(DUK_HOBJECT_HAS_SPECIAL_CALL(func));
#if defined(DUK_USE_ES6_PROXY)
if (DUK_HOBJECT_HAS_EXOTIC_PROXYOBJ(func)) {
/* If no trap, resume processing from Proxy trap.
* If trap exists, helper converts call into a trap
* call; this may change a constructor call into a
* normal (non-constructor) trap call. We must
* continue processing even when a trap is found as
* the trap may be bound.
*/
duk__handle_proxy_for_call(thr, idx_func, (duk_hproxy *) func, call_flags);
}
else
#endif
{
DUK_ASSERT(DUK_HOBJECT_IS_NATFUNC(func));
DUK_ASSERT(DUK_HOBJECT_HAS_CALLABLE(func));
DUK_ASSERT(!DUK_HOBJECT_HAS_CONSTRUCTABLE(func));
/* Constructable check already done above. */
if (duk__handle_specialfuncs_for_call(thr, idx_func, func, call_flags, first) != 0) {
/* Encountered native eval call, normal call
* context. Break out, handle this coercion etc.
*/
break;
}
}
}
/* Retry loop. */
} else if (DUK_TVAL_IS_LIGHTFUNC(tv_func)) {
/* Lightfuncs are:
* - Always strict, so no 'this' coercion.
* - Always callable.
* - Always constructable.
* - Never specialfuncs.
*/
func = NULL;
goto finished;
} else {
goto not_callable;
}
}
DUK_ASSERT(func != NULL);
if (!DUK_HOBJECT_HAS_STRICT(func)) {
/* Non-strict target needs 'this' coercion.
* This has potential side effects invalidating
* 'tv_func'.
*/
duk__coerce_nonstrict_this_binding(thr, idx_func + 1);
}
if (*call_flags & DUK_CALL_FLAG_CONSTRUCT) {
if (!(*call_flags & DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED)) {
*call_flags |= DUK_CALL_FLAG_DEFAULT_INSTANCE_UPDATED;
duk__update_default_instance_proto(thr, idx_func);
}
}
finished:
#if defined(DUK_USE_ASSERTIONS)
{
duk_tval *tv_tmp;
tv_tmp = duk_get_tval(thr, idx_func);
DUK_ASSERT(tv_tmp != NULL);
DUK_ASSERT((DUK_TVAL_IS_OBJECT(tv_tmp) && DUK_HOBJECT_IS_CALLABLE(DUK_TVAL_GET_OBJECT(tv_tmp))) ||
DUK_TVAL_IS_LIGHTFUNC(tv_tmp));
DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(func == NULL || (DUK_HOBJECT_IS_COMPFUNC(func) ||
DUK_HOBJECT_IS_NATFUNC(func)));
DUK_ASSERT(func == NULL || (DUK_HOBJECT_HAS_CONSTRUCTABLE(func) ||
(*call_flags & DUK_CALL_FLAG_CONSTRUCT) == 0));
}
#endif
return func;
not_callable:
DUK_ASSERT(tv_func != NULL);
#if defined(DUK_USE_VERBOSE_ERRORS)
/* GETPROPC delayed error handling: when target is not callable,
* GETPROPC replaces idx_func+0 with a non-callable wrapper object
* with a hidden Symbol to signify it's to be handled here. If
* found, unwrap the original Error and throw it as is here. The
* hidden Symbol is only checked as an own property, not inherited
* (which would be dangerous).
*/
if (DUK_TVAL_IS_OBJECT(tv_func)) {
duk_tval *tv_wrap = duk_hobject_find_entry_tval_ptr_stridx(thr->heap, DUK_TVAL_GET_OBJECT(tv_func), DUK_STRIDX_INT_TARGET);
if (tv_wrap != NULL) {
DUK_DD(DUK_DDPRINT("delayed error from GETPROPC: %!T", tv_wrap));
duk_push_tval(thr, tv_wrap);
(void) duk_throw(thr);
DUK_WO_NORETURN(return NULL;);
}
}
#endif
#if defined(DUK_USE_VERBOSE_ERRORS)
#if defined(DUK_USE_PARANOID_ERRORS)
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not callable", duk_get_type_name(thr, idx_func));
#else
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not callable", duk_push_string_tval_readable(thr, tv_func));
#endif
#else
DUK_ERROR_TYPE(thr, DUK_STR_NOT_CALLABLE);
#endif
DUK_WO_NORETURN(return NULL;);
not_constructable:
/* For now GETPROPC delayed error not needed for constructor calls. */
#if defined(DUK_USE_VERBOSE_ERRORS)
#if defined(DUK_USE_PARANOID_ERRORS)
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not constructable", duk_get_type_name(thr, idx_func));
#else
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "%s not constructable", duk_push_string_tval_readable(thr, tv_func));
#endif
#else
DUK_ERROR_TYPE(thr, DUK_STR_NOT_CONSTRUCTABLE);
#endif
DUK_WO_NORETURN(return NULL;);
}
/*
* 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_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(thr) - num_actual_rets; /* base of known return values */
if (DUK_UNLIKELY(idx_rcbase < 0)) {
DUK_ERROR_TYPE(thr, DUK_STR_INVALID_CFUNC_RC);
DUK_WO_NORETURN(return;);
}
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(thr),
(long) idx_retbase, (long) idx_rcbase));
DUK_ASSERT(idx_rcbase >= 0); /* caller must check */
/* Space for num_stack_rets was reserved before the safe call.
* Because value stack reserve cannot shrink except in call returns,
* the reserve is still in place. Adjust valstack, carefully
* ensuring we don't overstep the reserve.
*/
/* Match idx_rcbase with idx_retbase so that the return values
* start at the correct index.
*/
if (idx_rcbase > idx_retbase) {
duk_idx_t count = idx_rcbase - idx_retbase;
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));
/* Remove values between irc_rcbase (start of intended return
* values) and idx_retbase to lower return values to idx_retbase.
*/
DUK_ASSERT(count > 0);
duk_remove_n(thr, idx_retbase, count); /* may be NORZ */
} else {
duk_idx_t count = idx_retbase - idx_rcbase;
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' at idx_rcbase (start of intended return
* values) to lift return values to idx_retbase.
*/
DUK_ASSERT(count >= 0);
DUK_ASSERT(thr->valstack_end - thr->valstack_top >= count); /* reserve cannot shrink */
duk_insert_undefined_n(thr, idx_rcbase, count);
}
/* Chop extra retvals away / extend with undefined. */
duk_set_top_unsafe(thr, idx_retbase + num_stack_rets);
}
/*
* Activation setup for tailcalls and non-tailcalls.
*/
#if defined(DUK_USE_TAILCALL)
DUK_LOCAL duk_small_uint_t duk__call_setup_act_attempt_tailcall(duk_hthread *thr,
duk_small_uint_t call_flags,
duk_idx_t idx_func,
duk_hobject *func,
duk_size_t entry_valstack_bottom_byteoff,
duk_size_t entry_valstack_end_byteoff,
duk_idx_t *out_nargs,
duk_idx_t *out_nregs,
duk_size_t *out_vs_min_bytes,
duk_activation **out_act) {
duk_activation *act;
duk_tval *tv1, *tv2;
duk_idx_t idx_args;
duk_small_uint_t flags1, flags2;
#if defined(DUK_USE_DEBUGGER_SUPPORT)
duk_activation *prev_pause_act;
#endif
DUK_UNREF(entry_valstack_end_byteoff);
/* Tailcall cannot be flagged to resume calls, and a
* previous frame must exist.
*/
DUK_ASSERT(thr->callstack_top >= 1);
act = thr->callstack_curr;
DUK_ASSERT(act != NULL);
*out_act = act;
if (func == NULL || !DUK_HOBJECT_IS_COMPFUNC(func)) {
DUK_DDD(DUK_DDDPRINT("tail call prevented by target not being ecma function"));
return 0;
}
if (act->flags & DUK_ACT_FLAG_PREVENT_YIELD) {
DUK_DDD(DUK_DDDPRINT("tail call prevented by current activation having DUK_ACT_FLAG_PREVENT_YIELD"));
return 0;
}
/* Tailcall is only allowed if current and candidate
* function have identical return value handling. There
* are three possible return value handling cases:
* 1. Normal function call, no special return value handling.
* 2. Constructor call, return value replacement object check.
* 3. Proxy 'construct' trap call, return value invariant check.
*/
flags1 = (duk_small_uint_t) ((act->flags & DUK_ACT_FLAG_CONSTRUCT) ? 1 : 0)
#if defined(DUK_USE_ES6_PROXY)
| (duk_small_uint_t) ((act->flags & DUK_ACT_FLAG_CONSTRUCT_PROXY) ? 2 : 0)
#endif
;
flags2 = (duk_small_uint_t) ((call_flags & DUK_CALL_FLAG_CONSTRUCT) ? 1 : 0)
#if defined(DUK_USE_ES6_PROXY)
| (duk_small_uint_t) ((call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY) ? 2 : 0);
#endif
;
if (flags1 != flags2) {
DUK_DDD(DUK_DDDPRINT("tail call prevented by incompatible return value handling"));
return 0;
}
DUK_ASSERT(((act->flags & DUK_ACT_FLAG_CONSTRUCT) && (call_flags & DUK_CALL_FLAG_CONSTRUCT)) ||
(!(act->flags & DUK_ACT_FLAG_CONSTRUCT) && !(call_flags & DUK_CALL_FLAG_CONSTRUCT)));
DUK_ASSERT(((act->flags & DUK_ACT_FLAG_CONSTRUCT_PROXY) && (call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY)) ||
(!(act->flags & DUK_ACT_FLAG_CONSTRUCT_PROXY) && !(call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY)));
if (DUK_HOBJECT_HAS_NOTAIL(func)) {
/* See: test-bug-tailcall-preventyield-assert.c. */
DUK_DDD(DUK_DDDPRINT("tail call prevented by function having a notail flag"));
return 0;
}
/*
* 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 catchers need to be unwound
* because there may be non-error-catching label entries in valid tail calls.
*
* Special attention is needed for debugger and pause behavior when
* reusing an activation.
* - Disable StepOut processing for the activation unwind because
* we reuse the activation, see:
* https://github.com/svaarala/duktape/issues/1684.
* - Disable line change pause flag permanently if act == dbg_pause_act
* (if set) because it would no longer be relevant, see:
* https://github.com/svaarala/duktape/issues/1726,
* https://github.com/svaarala/duktape/issues/1786.
* - Check for function entry (e.g. StepInto) pause flag here, because
* the executor pause check won't trigger due to shared activation, see:
* https://github.com/svaarala/duktape/issues/1726.
*/
DUK_DDD(DUK_DDDPRINT("is tail call, reusing activation at callstack top, at index %ld",
(long) (thr->callstack_top - 1)));
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);
DUK_ASSERT(call_flags & DUK_CALL_FLAG_ALLOW_ECMATOECMA);
/* Unwind the topmost callstack entry before reusing it. This
* also unwinds the catchers related to the topmost entry.
*/
DUK_ASSERT(thr->callstack_top > 0);
DUK_ASSERT(thr->callstack_curr != NULL);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
if (act == thr->heap->dbg_pause_act) {
thr->heap->dbg_pause_flags &= ~DUK_PAUSE_FLAG_LINE_CHANGE;
}
prev_pause_act = thr->heap->dbg_pause_act;
thr->heap->dbg_pause_act = NULL;
if (thr->heap->dbg_pause_flags & DUK_PAUSE_FLAG_FUNC_ENTRY) {
DUK_D(DUK_DPRINT("PAUSE TRIGGERED by function entry (tailcall)"));
duk_debug_set_paused(thr->heap);
}
#endif
duk_hthread_activation_unwind_reuse_norz(thr);
#if defined(DUK_USE_DEBUGGER_SUPPORT)
thr->heap->dbg_pause_act = prev_pause_act;
#endif
DUK_ASSERT(act == thr->callstack_curr);
/* XXX: We could restore the caller's value stack reserve
* here, as if we did an actual unwind-and-call. Without
* the restoration, value stack reserve may remain higher
* than would otherwise be possible until we return to a
* non-tailcall.
*/
/* Then reuse the unwound activation. */
act->cat = NULL;
act->var_env = NULL;
act->lex_env = NULL;
DUK_ASSERT(func != NULL);
DUK_ASSERT(DUK_HOBJECT_HAS_COMPFUNC(func));
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
/* 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 */
DUK_HOBJECT_INCREF(thr, func);
act->flags = DUK_ACT_FLAG_TAILCALLED;
if (DUK_HOBJECT_HAS_STRICT(func)) {
act->flags |= DUK_ACT_FLAG_STRICT;
}
if (call_flags & DUK_CALL_FLAG_CONSTRUCT) {
act->flags |= DUK_ACT_FLAG_CONSTRUCT;
}
#if defined(DUK_USE_ES6_PROXY)
if (call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY) {
act->flags |= DUK_ACT_FLAG_CONSTRUCT_PROXY;
}
#endif
DUK_ASSERT(DUK_ACT_GET_FUNC(act) == func); /* already updated */
DUK_ASSERT(act->var_env == NULL);
DUK_ASSERT(act->lex_env == NULL);
act->bottom_byteoff = entry_valstack_bottom_byteoff; /* tail call -> reuse current "frame" */
#if 0
/* Topmost activation retval_byteoff is considered garbage, no need to init. */
act->retval_byteoff = 0;
#endif
/* Filled in when final reserve is known, dummy value doesn't matter
* even in error unwind because reserve_byteoff is only used when
* returning to -this- activation.
*/
act->reserve_byteoff = 0;
/*
* 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 */
idx_args = idx_func + 2;
duk_remove_n(thr, 0, idx_args); /* may be NORZ */
idx_func = 0; DUK_UNREF(idx_func); /* really 'not applicable' anymore, should not be referenced after this */
idx_args = 0;
*out_nargs = ((duk_hcompfunc *) func)->nargs;
*out_nregs = ((duk_hcompfunc *) func)->nregs;
DUK_ASSERT(*out_nregs >= 0);
DUK_ASSERT(*out_nregs >= *out_nargs);
*out_vs_min_bytes = entry_valstack_bottom_byteoff + sizeof(duk_tval) * ((duk_size_t) *out_nregs + DUK_VALSTACK_INTERNAL_EXTRA);
#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);
#endif
/* [ ... this_new | arg1 ... argN ] */
return 1;
}
#endif /* DUK_USE_TAILCALL */
DUK_LOCAL void duk__call_setup_act_not_tailcall(duk_hthread *thr,
duk_small_uint_t call_flags,
duk_idx_t idx_func,
duk_hobject *func,
duk_size_t entry_valstack_bottom_byteoff,
duk_size_t entry_valstack_end_byteoff,
duk_idx_t *out_nargs,
duk_idx_t *out_nregs,
duk_size_t *out_vs_min_bytes,
duk_activation **out_act) {
duk_activation *act;
duk_activation *new_act;
DUK_UNREF(entry_valstack_end_byteoff);
DUK_DDD(DUK_DDDPRINT("not a tail call, pushing a new activation to callstack, to index %ld",
(long) (thr->callstack_top)));
duk__call_callstack_limit_check(thr);
new_act = duk_hthread_activation_alloc(thr);
DUK_ASSERT(new_act != NULL);
act = thr->callstack_curr;
if (act != NULL) {
/*
* Update return value stack index of current activation (if any).
*
* 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 retval_byteoff must be set for things to work.
*/
act->retval_byteoff = entry_valstack_bottom_byteoff + (duk_size_t) idx_func * sizeof(duk_tval);
}
new_act->parent = act;
thr->callstack_curr = new_act;
thr->callstack_top++;
act = new_act;
*out_act = act;
DUK_ASSERT(thr->valstack_top > thr->valstack_bottom); /* at least effective 'this' */
DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));
act->cat = NULL;
act->flags = 0;
if (call_flags & DUK_CALL_FLAG_CONSTRUCT) {
act->flags |= DUK_ACT_FLAG_CONSTRUCT;
}
#if defined(DUK_USE_ES6_PROXY)
if (call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY) {
act->flags |= DUK_ACT_FLAG_CONSTRUCT_PROXY;
}
#endif
if (call_flags & DUK_CALL_FLAG_DIRECT_EVAL) {
act->flags |= DUK_ACT_FLAG_DIRECT_EVAL;
}
/* start of arguments: idx_func + 2. */
act->func = func; /* NULL for lightfunc */
if (DUK_LIKELY(func != NULL)) {
DUK_TVAL_SET_OBJECT(&act->tv_func, func); /* borrowed, no refcount */
if (DUK_HOBJECT_HAS_STRICT(func)) {
act->flags |= DUK_ACT_FLAG_STRICT;
}
if (DUK_HOBJECT_IS_COMPFUNC(func)) {
*out_nargs = ((duk_hcompfunc *) func)->nargs;
*out_nregs = ((duk_hcompfunc *) func)->nregs;
DUK_ASSERT(*out_nregs >= 0);
DUK_ASSERT(*out_nregs >= *out_nargs);
*out_vs_min_bytes = entry_valstack_bottom_byteoff +
sizeof(duk_tval) * ((duk_size_t) idx_func + 2U + (duk_size_t) *out_nregs + DUK_VALSTACK_INTERNAL_EXTRA);
} else {
/* True because of call target lookup checks. */
DUK_ASSERT(DUK_HOBJECT_IS_NATFUNC(func));
*out_nargs = ((duk_hnatfunc *) func)->nargs;
*out_nregs = *out_nargs;
if (*out_nargs >= 0) {
*out_vs_min_bytes = entry_valstack_bottom_byteoff +
sizeof(duk_tval) * ((duk_size_t) idx_func + 2U + (duk_size_t) *out_nregs + DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);
} else {
/* Vararg function. */
duk_size_t valstack_top_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - ((duk_uint8_t *) thr->valstack));
*out_vs_min_bytes = valstack_top_byteoff +
sizeof(duk_tval) * (DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);
}
}
} else {
duk_small_uint_t lf_flags;
duk_tval *tv_func;
act->flags |= DUK_ACT_FLAG_STRICT;
tv_func = DUK_GET_TVAL_POSIDX(thr, idx_func);
DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv_func));
DUK_TVAL_SET_TVAL(&act->tv_func, tv_func); /* borrowed, no refcount */
lf_flags = DUK_TVAL_GET_LIGHTFUNC_FLAGS(tv_func);
*out_nargs = DUK_LFUNC_FLAGS_GET_NARGS(lf_flags);
if (*out_nargs != DUK_LFUNC_NARGS_VARARGS) {
*out_vs_min_bytes = entry_valstack_bottom_byteoff +
sizeof(duk_tval) * ((duk_size_t) idx_func + 2U + (duk_size_t) *out_nargs + DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);
} else {
duk_size_t valstack_top_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_top - ((duk_uint8_t *) thr->valstack));
*out_vs_min_bytes = valstack_top_byteoff +
sizeof(duk_tval) * (DUK_VALSTACK_API_ENTRY_MINIMUM + DUK_VALSTACK_INTERNAL_EXTRA);
*out_nargs = -1; /* vararg */
}
*out_nregs = *out_nargs;
}
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->bottom_byteoff = entry_valstack_bottom_byteoff + sizeof(duk_tval) * ((duk_size_t) idx_func + 2U);
#if 0
act->retval_byteoff = 0; /* topmost activation retval_byteoff is considered garbage, no need to init */
#endif
/* Filled in when final reserve is known, dummy value doesn't matter
* even in error unwind because reserve_byteoff is only used when
* returning to -this- activation.
*/
act->reserve_byteoff = 0; /* filled in by caller */
/* 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);
}
#endif
}
/*
* Environment setup.
*/
DUK_LOCAL void duk__call_env_setup(duk_hthread *thr, duk_hobject *func, duk_activation *act, duk_idx_t idx_args) {
duk_hobject *env;
DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func)); /* bound function has already been resolved */
if (DUK_LIKELY(func != NULL)) {
if (DUK_LIKELY(DUK_HOBJECT_HAS_NEWENV(func))) {
DUK_STATS_INC(thr->heap, stats_envrec_newenv);
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 bottom_byteoff of new activation */
env = duk_create_activation_environment_record(thr, func, act->bottom_byteoff);
DUK_ASSERT(env != NULL);
/* [ ... func this arg1 ... argN envobj ] */
DUK_ASSERT(DUK_HOBJECT_HAS_CREATEARGS(func));
duk__handle_createargs_for_call(thr, func, env, idx_args);
/* [ ... func this arg1 ... argN envobj ] */
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(thr);
}
} 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_STATS_INC(thr->heap, stats_envrec_oldenv);
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);
DUK_STATS_INC(thr->heap, stats_envrec_newenv);
}
}
/*
* Misc shared helpers.
*/
/* Check thread state, update current thread. */
DUK_LOCAL void duk__call_thread_state_update(duk_hthread *thr) {
DUK_ASSERT(thr != NULL);
if (DUK_LIKELY(thr == thr->heap->curr_thread)) {
if (DUK_UNLIKELY(thr->state != DUK_HTHREAD_STATE_RUNNING)) {
/* Should actually never happen, but check anyway. */
goto thread_state_error;
}
} else {
DUK_ASSERT(thr->heap->curr_thread == NULL ||
thr->heap->curr_thread->state == DUK_HTHREAD_STATE_RUNNING);
if (DUK_UNLIKELY(thr->state != DUK_HTHREAD_STATE_INACTIVE)) {
goto thread_state_error;
}
DUK_HEAP_SWITCH_THREAD(thr->heap, thr);
thr->state = DUK_HTHREAD_STATE_RUNNING;
/* 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);
return;
thread_state_error:
DUK_ERROR_FMT1(thr, DUK_ERR_TYPE_ERROR, "invalid thread state (%ld)", (long) thr->state);
DUK_WO_NORETURN(return;);
}
/*
* Main unprotected call handler, handles:
*
* - All combinations of native/ECMAScript caller and native/ECMAScript
* target.
*
* - Optimized ECMAScript-to-ECMAScript call where call handling only
* sets up a new duk_activation but reuses an existing bytecode executor
* (the caller) without native recursion.
*
* - Tailcalls, where an activation is reused without increasing call
* stack (duk_activation) depth.
*
* - Setup for an initial Duktape.Thread.resume().
*
* The call handler doesn't provide any protection guarantees, protected calls
* must be implemented e.g. by wrapping the call in a duk_safe_call().
* Call setup may fail at any stage, even when the new activation is in
* place; the only guarantee is that the state is consistent for unwinding.
*/
DUK_LOCAL duk_int_t duk__handle_call_raw(duk_hthread *thr,
duk_idx_t idx_func,
duk_small_uint_t call_flags) {
#if defined(DUK_USE_ASSERTIONS)
duk_activation *entry_act;
duk_size_t entry_callstack_top;
#endif
duk_size_t entry_valstack_bottom_byteoff;
duk_size_t entry_valstack_end_byteoff;
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_args;
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_size_t vs_min_bytes; /* minimum value stack size (bytes) for handling call */
duk_hobject *func; /* 'func' on stack (borrowed reference) */
duk_activation *act;
duk_ret_t rc;
duk_small_uint_t use_tailcall;
DUK_ASSERT(thr != NULL);
DUK_ASSERT(thr->heap != NULL);
/* Asserts for heap->curr_thread omitted: it may be NULL, 'thr', or
* any other thread (e.g. when heap thread is used to run finalizers).
*/
DUK_CTX_ASSERT_VALID(thr);
DUK_ASSERT(duk_is_valid_index(thr, idx_func));
DUK_ASSERT(idx_func >= 0);
DUK_STATS_INC(thr->heap, stats_call_all);
/* If a tail call:
* - an ECMAScript activation must be on top of the callstack
* - there cannot be any catch stack entries that would catch
* a return
*/
#if defined(DUK_USE_ASSERTIONS)
if (call_flags & DUK_CALL_FLAG_TAILCALL) {
duk_activation *tmp_act;
duk_catcher *tmp_cat;
DUK_ASSERT(thr->callstack_top >= 1);
DUK_ASSERT(DUK_ACT_GET_FUNC(thr->callstack_curr) != NULL);
DUK_ASSERT(DUK_HOBJECT_IS_COMPFUNC(DUK_ACT_GET_FUNC(thr->callstack_curr)));
/* No entry in the catch stack which would actually catch a
* throw can refer to the callstack entry being reused.
* There *can* be catch stack entries referring to the current
* callstack entry as long as they don't catch (e.g. label sites).
*/
tmp_act = thr->callstack_curr;
for (tmp_cat = tmp_act->cat; tmp_cat != NULL; tmp_cat = tmp_cat->parent) {
DUK_ASSERT(DUK_CAT_GET_TYPE(tmp_cat) == DUK_CAT_TYPE_LABEL); /* a non-catching entry */
}
}
#endif /* DUK_USE_ASSERTIONS */
/*
* Store entry state.
*/
#if defined(DUK_USE_ASSERTIONS)
entry_act = thr->callstack_curr;
entry_callstack_top = thr->callstack_top;
#endif
entry_valstack_bottom_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack);
entry_valstack_end_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack);
entry_call_recursion_depth = thr->heap->call_recursion_depth;
entry_curr_thread = thr->heap->curr_thread; /* 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_ASSERT(thr->ptr_curr_pc == NULL);
DUK_DD(DUK_DDPRINT("duk__handle_call_raw: thr=%p, idx_func=%ld, "
"call_flags=0x%08lx (constructor=%ld), "
"valstack_top=%ld, idx_func=%ld, idx_args=%ld, rec_depth=%ld/%ld, "
"entry_valstack_bottom_byteoff=%ld, entry_valstack_end_byteoff=%ld, "
"entry_call_recursion_depth=%ld, "
"entry_curr_thread=%p, entry_thread_state=%ld",
(void *) thr,
(long) idx_func,
(unsigned long) call_flags,
(long) ((call_flags & DUK_CALL_FLAG_CONSTRUCT) != 0 ? 1 : 0),
(long) duk_get_top(thr),
(long) idx_func,
(long) (idx_func + 2),
(long) thr->heap->call_recursion_depth,
(long) thr->heap->call_recursion_limit,
(long) entry_valstack_bottom_byteoff,
(long) entry_valstack_end_byteoff,
(long) entry_call_recursion_depth,
(void *) entry_curr_thread,
(long) entry_thread_state));
/*
* Thread state check and book-keeping.
*/
duk__call_thread_state_update(thr);
/*
* Increase call recursion depth as early as possible so that if we
* enter a recursive call for any reason there's a backstop to native
* recursion. This can happen e.g. for almost any property read
* because it may cause a getter call or a Proxy trap (GC and finalizers
* are not an issue because they are not recursive). If we end up
* doing an Ecma-to-Ecma call, revert the increase. (See GH-2032.)
*
* For similar reasons, ensure there is a known value stack spare
* even before we actually prepare the value stack for the target
* function. If this isn't done, early recursion may consume the
* value stack space.
*
* XXX: Should bump yield preventcount early, for the same reason.
*/
duk__call_c_recursion_limit_check(thr);
thr->heap->call_recursion_depth++;
duk_require_stack(thr, DUK__CALL_HANDLING_REQUIRE_STACK);
/*
* Resolve final target function; handle bound functions and special
* functions like .call() and .apply(). Also figure out the effective
* 'this' binding, which replaces the current value at idx_func + 1.
*/
if (DUK_LIKELY(duk__resolve_target_fastpath_check(thr, idx_func, &func, call_flags) != 0U)) {
DUK_DDD(DUK_DDDPRINT("fast path target resolve"));
} else {
DUK_DDD(DUK_DDDPRINT("slow path target resolve"));
func = duk__resolve_target_func_and_this_binding(thr, idx_func, &call_flags);
}
DUK_ASSERT(duk_get_top(thr) - idx_func >= 2); /* at least func and this present */
DUK_ASSERT(func == NULL || !DUK_HOBJECT_HAS_BOUNDFUNC(func));
DUK_ASSERT(func == NULL || (DUK_HOBJECT_IS_COMPFUNC(func) ||
DUK_HOBJECT_IS_NATFUNC(func)));
/* [ ... func this arg1 ... argN ] */
/*
* Setup a preliminary activation and figure out nargs/nregs and
* value stack minimum size.
*
* Don't touch valstack_bottom or valstack_top yet so that Duktape API
* calls work normally.
*
* Because 'act' is not zeroed, all fields must be filled in.
*/
/* Should not be necessary, but initialize to silence warnings. */
act = NULL;
nargs = 0;
nregs = 0;
vs_min_bytes = 0;
#if defined(DUK_USE_TAILCALL)
use_tailcall = (call_flags & DUK_CALL_FLAG_TAILCALL);
if (use_tailcall) {
use_tailcall = duk__call_setup_act_attempt_tailcall(thr,
call_flags,
idx_func,
func,
entry_valstack_bottom_byteoff,
entry_valstack_end_byteoff,
&nargs,
&nregs,
&vs_min_bytes,
&act);
}
#else
DUK_ASSERT((call_flags & DUK_CALL_FLAG_TAILCALL) == 0); /* compiler ensures this */
use_tailcall = 0;
#endif
if (use_tailcall) {
idx_args = 0;
DUK_STATS_INC(thr->heap, stats_call_tailcall);
} else {
duk__call_setup_act_not_tailcall(thr,
call_flags,
idx_func,
func,
entry_valstack_bottom_byteoff,
entry_valstack_end_byteoff,
&nargs,
&nregs,
&vs_min_bytes,
&act);
idx_args = idx_func + 2;
}
/* After this point idx_func is no longer valid for tailcalls. */
DUK_ASSERT(act != NULL);
/* [ ... 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__call_env_setup(thr, func, act, idx_args);
/* [ ... func this arg1 ... argN ] */
/*
* Setup value stack: clamp to 'nargs', fill up to 'nregs',
* ensure value stack size matches target requirements, and
* switch value stack bottom. Valstack top is kept.
*
* Value stack can only grow here.
*/
duk_valstack_grow_check_throw(thr, vs_min_bytes);
act->reserve_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack);
if (use_tailcall) {
DUK_ASSERT(nregs >= 0);
DUK_ASSERT(nregs >= nargs);
duk_set_top_and_wipe(thr, nregs, nargs);
} else {
if (nregs >= 0) {
DUK_ASSERT(nregs >= nargs);
duk_set_top_and_wipe(thr, idx_func + 2 + nregs, idx_func + 2 + nargs);
} else {
;
}
thr->valstack_bottom = thr->valstack_bottom + idx_func + 2;
}
DUK_ASSERT(thr->valstack_bottom >= thr->valstack);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
/*
* Make the actual call. For Ecma-to-Ecma calls detect that
* setup is complete, then return with a status code that allows
* the caller to reuse the running executor.
*/
if (func != NULL && DUK_HOBJECT_IS_COMPFUNC(func)) {
/*
* ECMAScript call.
*/
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 (call_flags & DUK_CALL_FLAG_ALLOW_ECMATOECMA) {
DUK_DD(DUK_DDPRINT("avoid native call, use existing executor"));
DUK_STATS_INC(thr->heap, stats_call_ecmatoecma);
DUK_ASSERT((act->flags & DUK_ACT_FLAG_PREVENT_YIELD) == 0);
DUK_REFZERO_CHECK_FAST(thr);
DUK_ASSERT(thr->ptr_curr_pc == NULL);
thr->heap->call_recursion_depth--; /* No recursion increase for this case. */
return 1; /* 1=reuse executor */
}
DUK_ASSERT(use_tailcall == 0);
/* duk_hthread_activation_unwind_norz() will decrease this on unwind */
DUK_ASSERT((act->flags & DUK_ACT_FLAG_PREVENT_YIELD) == 0);
act->flags |= DUK_ACT_FLAG_PREVENT_YIELD;
thr->callstack_preventcount++;
/* [ ... 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"));
} else {
/*
* Native call.
*/
DUK_ASSERT(func == NULL || ((duk_hnatfunc *) func)->func != NULL);
DUK_ASSERT(use_tailcall == 0);
/* [ ... func this | arg1 ... argN ] ('this' must precede new bottom) */
/* duk_hthread_activation_unwind_norz() will decrease this on unwind */
DUK_ASSERT((act->flags & DUK_ACT_FLAG_PREVENT_YIELD) == 0);
act->flags |= DUK_ACT_FLAG_PREVENT_YIELD;
thr->callstack_preventcount++;
/* For native calls must be NULL so we don't sync back */
DUK_ASSERT(thr->ptr_curr_pc == NULL);
/* XXX: native funcptr could come out of call setup. */
if (func) {
rc = ((duk_hnatfunc *) func)->func(thr);
} else {
duk_tval *tv_func;
duk_c_function funcptr;
tv_func = &act->tv_func;
DUK_ASSERT(DUK_TVAL_IS_LIGHTFUNC(tv_func));
funcptr = DUK_TVAL_GET_LIGHTFUNC_FUNCPTR(tv_func);
rc = funcptr(thr);
}
/* Automatic error throwing, retval check. */
if (rc == 0) {
DUK_ASSERT(thr->valstack < thr->valstack_end);
DUK_ASSERT(DUK_TVAL_IS_UNDEFINED(thr->valstack_top));
thr->valstack_top++;
} else if (rc == 1) {
;
} else if (rc < 0) {
duk_error_throw_from_negative_rc(thr, rc);
DUK_WO_NORETURN(return 0;);
} else {
DUK_ERROR_TYPE(thr, DUK_STR_INVALID_CFUNC_RC);
DUK_WO_NORETURN(return 0;);
}
}
DUK_ASSERT(thr->ptr_curr_pc == NULL);
DUK_ASSERT(use_tailcall == 0);
/*
* Constructor call post processing.
*/
#if defined(DUK_USE_ES6_PROXY)
if (call_flags & (DUK_CALL_FLAG_CONSTRUCT | DUK_CALL_FLAG_CONSTRUCT_PROXY)) {
duk_call_construct_postprocess(thr, call_flags & DUK_CALL_FLAG_CONSTRUCT_PROXY);
}
#else
if (call_flags & DUK_CALL_FLAG_CONSTRUCT) {
duk_call_construct_postprocess(thr, 0);
}
#endif
/*
* Unwind, restore valstack bottom and other book-keeping.
*/
DUK_ASSERT(thr->callstack_curr != NULL);
DUK_ASSERT(thr->callstack_curr->parent == entry_act);
DUK_ASSERT(thr->callstack_top == entry_callstack_top + 1);
duk_hthread_activation_unwind_norz(thr);
DUK_ASSERT(thr->callstack_curr == entry_act);
DUK_ASSERT(thr->callstack_top == entry_callstack_top);
thr->valstack_bottom = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + entry_valstack_bottom_byteoff);
/* 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 ] */
{
duk_tval *tv_ret;
duk_tval *tv_funret;
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_FAST(tv_funret);
#endif
DUK_TVAL_SET_TVAL_UPDREF(thr, tv_ret, tv_funret); /* side effects */
}
duk_set_top_unsafe(thr, idx_func + 1);
/* [ ... retval ] */
/* Restore caller's value stack reserve (cannot fail). */
DUK_ASSERT((duk_uint8_t *) thr->valstack + entry_valstack_end_byteoff >= (duk_uint8_t *) thr->valstack_top);
DUK_ASSERT((duk_uint8_t *) thr->valstack + entry_valstack_end_byteoff <= (duk_uint8_t *) thr->valstack_alloc_end);
thr->valstack_end = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + entry_valstack_end_byteoff);
/* XXX: Trial value stack shrink would be OK here, but we'd need
* to prevent side effects of the potential realloc.
*/
/* 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;
/* Disabled assert: triggered with some torture tests. */
#if 0
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 */
#endif
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_debug_is_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
/* Restored by success path. */
DUK_ASSERT(thr->heap->call_recursion_depth == entry_call_recursion_depth);
DUK_ASSERT(thr->ptr_curr_pc == entry_ptr_curr_pc);
DUK_ASSERT_LJSTATE_UNSET(thr->heap);
DUK_REFZERO_CHECK_FAST(thr);
return 0; /* 0=call handled inline */
}
DUK_INTERNAL duk_int_t duk_handle_call_unprotected_nargs(duk_hthread *thr,
duk_idx_t nargs,
duk_small_uint_t call_flags) {
duk_idx_t idx_func;
DUK_ASSERT(duk_get_top(thr) >= nargs + 2);
idx_func = duk_get_top(thr) - (nargs + 2);
DUK_ASSERT(idx_func >= 0);
return duk_handle_call_unprotected(thr, idx_func, call_flags);
}
DUK_INTERNAL duk_int_t duk_handle_call_unprotected(duk_hthread *thr,
duk_idx_t idx_func,
duk_small_uint_t call_flags) {
DUK_ASSERT(duk_is_valid_index(thr, idx_func));
DUK_ASSERT(idx_func >= 0);
return duk__handle_call_raw(thr, idx_func, call_flags);
}
/*
* 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_protected().
*
* Even though this call is protected, errors are thrown for insane arguments
* and may result in a fatal error unless there's another protected call which
* catches such errors.
*
* The error handling path should be error free, even for out-of-memory
* errors, to ensure safe sandboxing. (As of Duktape 2.2.0 this is not
* yet the case for environment closing which may run out of memory, see
* XXX notes below.)
*/
DUK_LOCAL void duk__handle_safe_call_inner(duk_hthread *thr,
duk_safe_call_function func,
void *udata,
#if defined(DUK_USE_ASSERTIONS)
duk_size_t entry_valstack_bottom_byteoff,
duk_size_t entry_callstack_top,
#endif
duk_hthread *entry_curr_thread,
duk_uint_fast8_t entry_thread_state,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets) {
duk_ret_t rc;
DUK_ASSERT(thr != NULL);
DUK_CTX_ASSERT_VALID(thr);
/*
* Thread state check and book-keeping.
*/
duk__call_thread_state_update(thr);
/*
* Recursion limit check.
*/
duk__call_c_recursion_limit_check(thr);
thr->heap->call_recursion_depth++;
/*
* Make the C call.
*/
rc = func(thr, 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->valstack_bottom >= thr->valstack);
DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack) == entry_valstack_bottom_byteoff);
DUK_ASSERT(thr->valstack_top >= thr->valstack_bottom);
DUK_ASSERT(thr->valstack_end >= thr->valstack_top);
if (DUK_UNLIKELY(rc < 0)) {
duk_error_throw_from_negative_rc(thr, rc);
DUK_WO_NORETURN(return;);
}
DUK_ASSERT(rc >= 0);
duk__safe_call_adjust_valstack(thr, idx_retbase, num_stack_rets, rc); /* throws for insane rc */
DUK_HEAP_SWITCH_THREAD(thr->heap, entry_curr_thread); /* may be NULL */
thr->state = (duk_uint8_t) entry_thread_state;
}
DUK_LOCAL void duk__handle_safe_call_error(duk_hthread *thr,
duk_activation *entry_act,
#if defined(DUK_USE_ASSERTIONS)
duk_size_t entry_callstack_top,
#endif
duk_hthread *entry_curr_thread,
duk_uint_fast8_t entry_thread_state,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets,
duk_size_t entry_valstack_bottom_byteoff,
duk_jmpbuf *old_jmpbuf_ptr) {
DUK_ASSERT(thr != NULL);
DUK_CTX_ASSERT_VALID(thr);
/*
* 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_LJSTATE_SET(thr->heap);
/* Either pointer may be NULL (at entry), so don't assert. */
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
*/
/* XXX: "unwind to" primitive? */
DUK_ASSERT(thr->callstack_top >= entry_callstack_top);
while (thr->callstack_curr != entry_act) {
DUK_ASSERT(thr->callstack_curr != NULL);
duk_hthread_activation_unwind_norz(thr);
}
DUK_ASSERT(thr->callstack_top == entry_callstack_top);
/* Switch active thread before any side effects to avoid a
* dangling curr_thread pointer.
*/
DUK_HEAP_SWITCH_THREAD(thr->heap, entry_curr_thread); /* may be NULL */
thr->state = (duk_uint8_t) entry_thread_state;
DUK_ASSERT(thr->heap->curr_thread == entry_curr_thread);
DUK_ASSERT(thr->state == entry_thread_state);
/* Restore valstack bottom. */
thr->valstack_bottom = (duk_tval *) (void *) ((duk_uint8_t *) thr->valstack + entry_valstack_bottom_byteoff);
/* [ ... | (crud) ] */
/* XXX: ensure space in valstack (now relies on internal reserve)? */
duk_push_tval(thr, &thr->heap->lj.value1);
/* [ ... | (crud) errobj ] */
DUK_ASSERT(duk_get_top(thr) >= 1); /* at least errobj must be on stack */
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 */
/* Reset longjmp state. */
thr->heap->lj.type = DUK_LJ_TYPE_UNKNOWN;
thr->heap->lj.iserror = 0;
DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, &thr->heap->lj.value1);
DUK_TVAL_SET_UNDEFINED_UPDREF_NORZ(thr, &thr->heap->lj.value2);
/* Error handling complete, remove side effect protections. Caller
* will process pending finalizers.
*/
#if defined(DUK_USE_ASSERTIONS)
DUK_ASSERT(thr->heap->error_not_allowed == 1);
thr->heap->error_not_allowed = 0;
#endif
DUK_ASSERT(thr->heap->pf_prevent_count > 0);
thr->heap->pf_prevent_count--;
DUK_DD(DUK_DDPRINT("safe call error handled, pf_prevent_count updated to %ld", (long) thr->heap->pf_prevent_count));
/* thr->ptr_curr_pc is restored by
* duk__handle_safe_call_shared_unwind() which is also used for
* success path.
*/
}
DUK_LOCAL void duk__handle_safe_call_shared_unwind(duk_hthread *thr,
duk_idx_t idx_retbase,
duk_idx_t num_stack_rets,
#if defined(DUK_USE_ASSERTIONS)
duk_size_t entry_callstack_top,
#endif
duk_int_t entry_call_recursion_depth,
duk_hthread *entry_curr_thread,
duk_instr_t **entry_ptr_curr_pc) {
DUK_ASSERT(thr != NULL);
DUK_CTX_ASSERT_VALID(thr);
DUK_UNREF(idx_retbase);
DUK_UNREF(num_stack_rets);
DUK_UNREF(entry_curr_thread);
DUK_ASSERT(thr->callstack_top == entry_callstack_top);
/* Restore entry thread executor curr_pc stack frame pointer.
* XXX: would be enough to do in error path only, should nest
* cleanly in success path.
*/
thr->ptr_curr_pc = entry_ptr_curr_pc;
thr->heap->call_recursion_depth = entry_call_recursion_depth;
/* stack discipline consistency check */
DUK_ASSERT(duk_get_top(thr) == 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
}
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_activation *entry_act;
duk_size_t entry_valstack_bottom_byteoff;
#if defined(DUK_USE_ASSERTIONS)
duk_size_t entry_valstack_end_byteoff;
duk_size_t entry_callstack_top;
duk_size_t entry_callstack_preventcount;
#endif
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(duk_get_top(thr) >= num_stack_args); /* Caller ensures. */
DUK_STATS_INC(thr->heap, stats_safecall_all);
/* Value stack reserve handling: safe call assumes caller has reserved
* space for nrets (assuming optimal unwind processing). Value stack
* reserve is not stored/restored as for normal calls because a safe
* call conceptually happens in the same activation.
*/
/* Careful with indices like '-x'; if 'x' is zero, it refers to bottom */
entry_act = thr->callstack_curr;
entry_valstack_bottom_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack);
#if defined(DUK_USE_ASSERTIONS)
entry_valstack_end_byteoff = (duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack);
entry_callstack_top = thr->callstack_top;
entry_callstack_preventcount = thr->callstack_preventcount;
#endif
entry_call_recursion_depth = thr->heap->call_recursion_depth;
entry_curr_thread = thr->heap->curr_thread; /* 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(thr) - num_stack_args; /* not a valid stack index if num_stack_args == 0 */
DUK_ASSERT(idx_retbase >= 0);
DUK_ASSERT((duk_idx_t) (thr->valstack_top - thr->valstack_bottom) >= num_stack_args); /* Caller ensures. */
DUK_ASSERT((duk_idx_t) (thr->valstack_end - (thr->valstack_bottom + idx_retbase)) >= num_stack_rets); /* Caller ensures. */
/* 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_act=%p, entry_valstack_bottom_byteoff=%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(thr),
(long) idx_retbase,
(long) thr->heap->call_recursion_depth,
(long) thr->heap->call_recursion_limit,
(void *) entry_act,
(long) entry_valstack_bottom_byteoff,
(long) entry_call_recursion_depth,
(void *) entry_curr_thread,
(long) entry_thread_state));
/* Setjmp catchpoint setup. */
old_jmpbuf_ptr = thr->heap->lj.jmpbuf_ptr;
thr->heap->lj.jmpbuf_ptr = &our_jmpbuf;
/* Prevent yields for the duration of the safe call. This only
* matters if the executor makes safe calls to functions that
* yield, this doesn't currently happen.
*/
thr->callstack_preventcount++;
#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,
#if defined(DUK_USE_ASSERTIONS)
entry_valstack_bottom_byteoff,
entry_callstack_top,
#endif
entry_curr_thread,
entry_thread_state,
idx_retbase,
num_stack_rets);
DUK_STATS_INC(thr->heap, stats_safecall_nothrow);
/* Either pointer may be NULL (at entry), so don't assert */
thr->heap->lj.jmpbuf_ptr = old_jmpbuf_ptr;
/* If calls happen inside the safe call, these are restored by
* whatever calls are made. Reserve cannot decrease.
*/
DUK_ASSERT(thr->callstack_curr == entry_act);
DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
retval = DUK_EXEC_SUCCESS;
#if defined(DUK_USE_CPP_EXCEPTIONS)
} catch (duk_internal_exception &exc) {
DUK_UNREF(exc);
#else
} else {
/* Error path. */
#endif
DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
DUK_STATS_INC(thr->heap, stats_safecall_throw);
duk__handle_safe_call_error(thr,
entry_act,
#if defined(DUK_USE_ASSERTIONS)
entry_callstack_top,
#endif
entry_curr_thread,
entry_thread_state,
idx_retbase,
num_stack_rets,
entry_valstack_bottom_byteoff,
old_jmpbuf_ptr);
retval = DUK_EXEC_ERROR;
}
#if defined(DUK_USE_CPP_EXCEPTIONS)
catch (duk_fatal_exception &exc) {
DUK_D(DUK_DPRINT("rethrow duk_fatal_exception"));
DUK_UNREF(exc);
throw;
} catch (std::exception &exc) {
const char *what = exc.what();
DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
DUK_STATS_INC(thr->heap, stats_safecall_throw);
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);
DUK_WO_NORETURN(return 0;);
} 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,
entry_act,
#if defined(DUK_USE_ASSERTIONS)
entry_callstack_top,
#endif
entry_curr_thread,
entry_thread_state,
idx_retbase,
num_stack_rets,
entry_valstack_bottom_byteoff,
old_jmpbuf_ptr);
retval = DUK_EXEC_ERROR;
}
} catch (...) {
DUK_D(DUK_DPRINT("unexpected c++ exception (perhaps thrown by user code)"));
DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
DUK_STATS_INC(thr->heap, stats_safecall_throw);
try {
DUK_ERROR_TYPE(thr, "caught invalid c++ exception (perhaps thrown by user code)");
DUK_WO_NORETURN(return 0;);
} 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,
entry_act,
#if defined(DUK_USE_ASSERTIONS)
entry_callstack_top,
#endif
entry_curr_thread,
entry_thread_state,
idx_retbase,
num_stack_rets,
entry_valstack_bottom_byteoff,
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_ASSERT_LJSTATE_UNSET(thr->heap);
DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
duk__handle_safe_call_shared_unwind(thr,
idx_retbase,
num_stack_rets,
#if defined(DUK_USE_ASSERTIONS)
entry_callstack_top,
#endif
entry_call_recursion_depth,
entry_curr_thread,
entry_ptr_curr_pc);
/* Restore preventcount. */
thr->callstack_preventcount--;
DUK_ASSERT(thr->callstack_preventcount == entry_callstack_preventcount);
/* Final asserts. */
DUK_ASSERT(thr->callstack_curr == entry_act);
DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_bottom - (duk_uint8_t *) thr->valstack) == entry_valstack_bottom_byteoff);
DUK_ASSERT((duk_size_t) ((duk_uint8_t *) thr->valstack_end - (duk_uint8_t *) thr->valstack) >= entry_valstack_end_byteoff);
DUK_ASSERT(thr->callstack_top == entry_callstack_top);
DUK_ASSERT(thr->heap->call_recursion_depth == entry_call_recursion_depth);
DUK_ASSERT(thr->heap->curr_thread == entry_curr_thread);
DUK_ASSERT(thr->state == entry_thread_state);
DUK_ASSERT(thr->ptr_curr_pc == entry_ptr_curr_pc);
DUK_ASSERT(duk_get_top(thr) == idx_retbase + num_stack_rets);
DUK_ASSERT_LJSTATE_UNSET(thr->heap);
/* Pending side effects. */
DUK_REFZERO_CHECK_FAST(thr);
return retval;
}
/*
* Property-based call (foo.noSuch()) error setup: replace target function
* on stack top with a hidden Symbol tagged non-callable wrapper object
* holding the error. The error gets thrown in call handling at the
* proper spot to follow ECMAScript semantics.
*/
#if defined(DUK_USE_VERBOSE_ERRORS)
DUK_INTERNAL DUK_NOINLINE DUK_COLD void duk_call_setup_propcall_error(duk_hthread *thr, duk_tval *tv_base, duk_tval *tv_key) {
const char *str_targ, *str_key, *str_base;
duk_idx_t entry_top;
entry_top = duk_get_top(thr);
/* [ <nargs> target ] */
/* Must stabilize pointers first. tv_targ is already on stack top. */
duk_push_tval(thr, tv_base);
duk_push_tval(thr, tv_key);
DUK_GC_TORTURE(thr->heap);
duk_push_bare_object(thr);
/* [ <nargs> target base key {} ] */
/* We only push a wrapped error, replacing the call target (at
* idx_func) with the error to ensure side effects come out
* correctly:
* - Property read
* - Call argument evaluation
* - Callability check and error thrown
*
* A hidden Symbol on the wrapper object pushed above is used by
* call handling to figure out the error is to be thrown as is.
* It is CRITICAL that the hidden Symbol can never occur on a
* user visible object that may get thrown.
*/
#if defined(DUK_USE_PARANOID_ERRORS)
str_targ = duk_get_type_name(thr, -4);
str_key = duk_get_type_name(thr, -2);
str_base = duk_get_type_name(thr, -3);
duk_push_error_object(thr,
DUK_ERR_TYPE_ERROR | DUK_ERRCODE_FLAG_NOBLAME_FILELINE,
"%s not callable (property %s of %s)", str_targ, str_key, str_base);
duk_xdef_prop_stridx(thr, -2, DUK_STRIDX_INT_TARGET, DUK_PROPDESC_FLAGS_NONE); /* Marker property, reuse _Target. */
/* [ <nargs> target base key { _Target: error } ] */
duk_replace(thr, entry_top - 1);
#else
str_targ = duk_push_string_readable(thr, -4);
str_key = duk_push_string_readable(thr, -3);
str_base = duk_push_string_readable(thr, -5);
duk_push_error_object(thr,
DUK_ERR_TYPE_ERROR | DUK_ERRCODE_FLAG_NOBLAME_FILELINE,
"%s not callable (property %s of %s)", str_targ, str_key, str_base);
/* [ <nargs> target base key {} str_targ str_key str_base error ] */
duk_xdef_prop_stridx(thr, -5, DUK_STRIDX_INT_TARGET, DUK_PROPDESC_FLAGS_NONE); /* Marker property, reuse _Target. */
/* [ <nargs> target base key { _Target: error } str_targ str_key str_base ] */
duk_swap(thr, -4, entry_top - 1);
/* [ <nargs> { _Target: error } base key target str_targ str_key str_base ] */
#endif
/* [ <nregs> { _Target: error } <variable> */
duk_set_top(thr, entry_top);
/* [ <nregs> { _Target: error } */
DUK_ASSERT(!duk_is_callable(thr, -1)); /* Critical so that call handling will throw the error. */
}
#endif /* DUK_USE_VERBOSE_ERRORS */