* Add internal helper for OrdinaryHasInstance(), needed by
Function.prototype[@@hasInstance].
* Add internal helper duk_get_method_stridx() which implements the ES2015
GetMethod() specification function.
* Add internal helper duk_to_boolean_top_pop() which occurs in a few
places and shaves some footprint.
* Extend duk_instanceof() and the internal duk_js_instanceof() helper
to include a target @@hasInstance check.
* Add Symbol.hasInstance and Function.prototype[@@hasInstance].
* Add support for non-default attributes for function properties,
needed by Function.prototype[@@hasInstance]. This also fixes
the incorrect attributes of performance.now().
* Change duk_bool_to to duk_small_uint_t from duk_small_int_t. This may
cause some sign warnings in calling code.
* Reject attempt to unpack an array-like value whose length is 2G or over;
previously was not checked explicitly, and the length was cast to duk_idx_t
with a sign change and the unpack would then later fail. Now it fails with
a clean RangeError.
* Add wrap check for Node.js Buffer.concat().
* API DUK_TYPE_xxx, DUK_TYPE_MASK_xxx, flag constants etc are now unsigned.
Both duk_hthread and duk_context typedefs resolve to struct duk_hthread
internally. In external API duk_context resolves to struct duk_hthread
which is intentionally left undefined as the struct itself is not
dereferenced. Change internal code to use duk_hthread exclusively which
removes unnecessary and awkward thr <-> ctx casts from internals.
The basic guidelines are:
* Public API uses duk_context in prototype declarations. The intent is to
hide the internal type, and there's already a wide dependency on the
type name.
* All internal code, both declarations and definitions, use duk_hthread
exclusively. This is done even for API functions, i.e. an API function
declared as "void duk_foo(duk_context *ctx);" is then defined as
"void duk_foo(duk_hthread *thr);".
Remove the special ecma-to-ecma call setup code and just use the normal
unprotected call setup code for that instead. Most of the code is the
same; just before calling into the bytecode executor check if the current
executor can be reused, and if so, indicate the situation using a special
return code.
Also remove internal duk_handle_call_protected() and implement all
protected API calls via duk_safe_call(). This reduces footprint and code
duplication further.
Rework call handling to use helpers more to make the call handling code
easier to follow.
Various other minor changer, e.g. DUK_OP_NEW is now DUK_OP_CONSCALL and
bytecode sets up the initial default instance.
* Make value stack and call stack limits configurable via DUK_USE_xxx
options. Also make value stack grow/shrink constants configurable.
* Rewrite value stack grow/shrink check primitives for better hot/cold path
handling.
* Use a proportional spare for grow and shrink sizes so that applications
needing a large value stack have fewer value stack resizes.
* Grow value stack allocation when entering a call or when explicitly requested
via e.g. duk_require_stack().
* Never shrink the value stack when entering a call, so that the unwind path
is guaranteed to have value stack to handle a protected call return. This
guarantee is only needed for protected call but is now applied to all calls
for simplicity.
* Don't perform a value stack shrink check at all in function return anymore.
It would be OK from protected call semantics perspective to do a shrink
attempt without throwing if it fails.
* Perform a value stack shrink check in mark-and-sweep only for now. When
emergency GC is running, shrink to a minimal size respecting current value
stack reserve.
Remove thr->callstack as a monolithic array and replace it with a linked list
of duk_activations. thr->callstack_curr is the current call (or NULL if no
call is in progress), and act->parent chains to a previous call or NULL.
thr->callstack_top is kept because it's needed by some internals at present;
it may be removed in the future.
This avoids the need for a function call and up to two property lookups
for a `Math.pow()` invocation, as well as allowing expressions like
`2 ** 16` to be inlined at compile time.
Exponentiation uses the same internal handler as `Math.pow()`, per the
ES7 specification.
Usage:
x = base ** exp;
x **= 2;
Change dispatch to use an 8-bit main opcode instead of a 6-bit one.
This removes the need for "EXTRA" opcodes and a secondary switch
clause in the executor dispatch loop.
The new opcode layout uses four 8-bit fields: opcode, A, B, C. The
previous reg/const concept which used 9-bit B and C fields, with the
top bit reserved to denote reg vs const, is now implemented by using
four consecutive opcode slots and moving the B and C reg/const flags
into the opcode. For example:
ADD_RR reg(A) <- reg(B) + reg(C)
ADD_CR reg(A) <- const(B) + reg(C)
ADD_RC reg(A) <- reg(B) + const(C)
ADD_CC reg(A) <- const(B) + const(C)
From a footprint standpoint this allows the executor to remain roughly
the same size: four dispatched opcodes (each a function pointer in a
compiled jump table) point to the same case clause handler, which does
the reg/const decision based on an instruction bit test as before.
However, when performance is more important than footprint, each reg/const
case can be handled separately in the executor so that there's no longer
a reg/const check when the opcode executes.
Note that not all opcodes require a reg/const qualifier, so that opcode
space is effectively increased even if reg/const opcodes consume multiple
entries from the opcode table.
Other minor changes:
* Optimize behavior of several opcodes to e.g. avoid unnecessary support
for shuffling/indirection when wider register arguments are now
available.
Improve readability by doing the following renames:
* duk_hcompiledfunction -> duk_hcompfunc
* duk_hnativefunction -> duk_hnatfunc
* duk_hbufferobject -> duk_hbufobj
Corresponding renames for all caps defines.
This makes it easier to pass C pointers to state structs etc without having
to use duk_push_pointer() and the value stack.
Change internal duk_safe_call() sites to use udata where appropriate.
Eval code doesn't need an automatic prototype object, so avoid creating one.
This also avoids making the internal function which eval compiles to part of
a reference loop so that eval functions collect immediately.
Separate call handling into three functions: unprotected call wrapper,
protected call wrapper, and a shared inner call handler. Having setjmp
only in a smaller wrapper reduces problems with compiler, including:
* Spurious volatile warnings
* Performance impact on compilers where optimizations must be disabled for
any function involving a setjmp
Also make every DUK_SETJMP() call site compatible with a later refactoring
to supporting C++ exceptions by handling the success case in the then-block
and the error in the else-block. This allows a try-catch structure to
trivially replace the setjmp construct.
Split call error handling to separate function which makes it easier to
share for C++ exception handling which may need a catch (xxx) for Duktape
errors and a separate catch (...) for other errors accidentally thrown by
user code.
Other minor cleanups in call handling.
A lot of changes to add preliminary lightfunc support:
* Add LIGHTFUNC tagged type to duk_tval.h and API.
* Internal changes for preliminary to support lightfuncs in call handling
and other operations (FIXMEs left in obvious places where support is
still missing after this commit)
* Preliminary Ecmascript and API testcases for lightfuncs
Detailed notes:
* Because magic is signed, reading it back involves sign extension which is
quite verbose to do in C. Use macros for reading the magic value and other
bit fields encoded in the flags.
* Function.prototype.bind(): the 'length' property of a bound function now
comes out wrong. We could simply look up the virtual 'length' property
even if h_target is NULL: no extra code and binding is relatively rare in
hot paths. Rewrite more cleanly in any case.
* The use flag DUK_USE_LIGHTFUNC_BUILTINS controls the forced lightfunc
conversion of built-ins. This results in non-compliant built-ins but
significant memory savings in very memory poor environments.
* Reject eval(), Thread.yield/resume as lightfuncs. These functions have
current assertions that they must be called as fully fledged functions.
* Lightfuncs are serialized like ordinary functions for JSON, JX, and JC
by this diff.
* Add 'magic' to activation for lightfuncs. It will be needed for lightweight
functions: we don't have the duk_tval related to the lightfunc, so we must
copy the magic value to the activation when a call is made.
* When lightfuncs are used as property lookup base values, continue property
lookup from the Function.prototype object. This is necessary to allow e.g.
``func.call()`` and ``func.apply()`` to be used.
* Call handling had to be reworked for lightfuncs, especially how bound
function chains are handled. This is a relatively large change but is
necessary to support lightweight functions properly in bound function
resolution.
The current solution is not ideal. The bytecode executor will first try an
ecma-to-ecma call setup which resolves the bound function chain first. If
the final, unbound function is not viable (a native function) the call setup
returns with an error code. The caller will then perform a normal call.
Although bound function resolution has already been done, the normal call
handling code will re-do it (and detect there is nothing to do).
This situation could be avoided by decoupling bound function handling and
effective this binding computation from the actual call setup. The caller
could then to do this prestep first, and only then decide whether to use an
ecma-to-ecma call or an ordinary heavyweight call.
Remove duk__find_nonbound_function as unused.
* Use indirect magic to allow LIGHTFUNCs for Date. Most of the built-in
functions not directly eligible as lightfuncs are the Date built-in methods,
whose magic values contain too much information to fit into the 8-bit magic
of a LIGHTFUNC value.
To work around this, add an array (duk__date_magics[]) containing the
actual control flags needed by the built-ins, and make the Date built-in
magic value an index into this table. With this change Date built-ins are
successfully converted to lightfuncs.
Testcase fixes:
- Whitespace fixes
- Print error for indirect eval error to make diagnosis easier
- Fix error string to match errmsg updated in this branch
These were revealed after fixing DUK_SINGLE_FILE, gcc will complain about
these internal functions being declared, defined, but not used. There were
also a few declared functions that did not exist. Compiled binary size was
reduced by a few kilobytes!
Unused functions must be commented out carefully: some functions might be
used with certain feature options but not by the defaults. These removals
were verified with grep.
There are no call sites for DUK_DEBUG_DUMP_HEAP() so all the functions
in duk_debug_heap.c are unused, even with a debug build.
Out of the checked allocation macros, only DUK_REALLOC_INDIRECT_CHECKED() is
actually in use at the moment. This commit just comments the unused stuff
out, but it might be better to just remove the unused stuff entirely.
Sami Vaarala
Bruce Pascoe