Also provide explicit fast / slow (small) variants for fastint downgrade
check: it doesn't make sense to inline the very large check except in the
hot paths of executor and call handling. Elsewhere it's better to save
footprint and thus code cache.
These can be used whenever we're 100% certain that the value stack index
exists and the type matches expected type. When these are true, a
duk_hstring, duk_hbuffer, or duk_hobject pointer fetch can be inlined to
small code.
Saves a few hundred bytes of footprint:
* duk_dup_0() = duk_dup(ctx, 0), duk_dup_1() = duk_dup(ctx, 1), etc.
* duk_dup_m2() = duk_dup(ctx, -2), etc.
* duk_dup_m1() is not added, because duk_dup_top() is the same thing
These don't play well with the API currently: the Duktape specific error
codes don't have Ecmascript Error class counterparts so they don't get
represented usefully as Ecmascript objects (e.g. AllocError is a plain
Error from Ecmascript point of view).
There's no real need for Duktape specific error code. Some of the codes
had become unused; a couple were used but Ecmascript standard types can
be used instead.
Also minor error message tweaking.
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.
* Use shared error macros and shared error handler to reduce the size of call
sites of common errors.
* Make zero argument DUK_ERROR() calls non-vararg calls to reduce call site
footprint. Non-vararg calls have smaller call sites and because there are
a lot of call sites, this turns out to be significant.
* Remove variadic macros from internal DUK_ERROR() macro set and add separate
macros for argument counts 0 to 4; this is more portable and requires less
conditional code, and works well when a non-vararg call is used for most
error call sites.
* Rework macro / function argument order for the error path, try to keep 'thr'
in the same argument slot to avoid unnecessary register moves.
* Pack linenumber and error code into a single 32-bit argument when possible,
removes one more constant load from the call site.
* Convert some internal errors to RangeErrors when the underlying cause is an
implementation limit (such as a compiler temp limit) rather than an actual
unexpected internal situation.
* Simplify and share a few error messages to reduce string count.
This is not strictly necessary but a convention used elsewhere too.
It's slightly less risky because duk_tval macros use argument names
like 'tv' and if a variable has the same name there can be subtle
bugs if there are typos in the macros.
Cast through "void *" when casting from e.g. a duk_uint8_t pointer
to a pointer with more alignment requirements (such as a struct pointer).
This is probably the best fix for cases where one also needs to do
pointer arithmetic (for which a char pointer is preferable). In cases
where pointer arithmetic is not necessarily, the original pointer could
in some cases be changed from a char pointer to a void pointer.
Sami Vaarala