* Replace the two alternative algorithms with a single one which works for
both desktop and low memory cases.
* Basic algorithm is a hash table with size 2^N, hash mask is simply
(size - 1), e.g. if size is 0x100, mask is 0xFF. duk_hstring has a 'next'
pointer (single linked list) for chaining strings mapping to the same
slot.
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.
* 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.
Lots of minor string format cleanups (casts mainly).
Add a special check to detect NULL pointers with %s/%p formats in debug
logging to avoid calling the platform sprintf() with a NULL value. This
is especially important for %s + NULL, which is not portable and may crash
on some platforms. Debug logging will now format these specially as "NULL"
and avoid calling the platform for formatting, so debug log call sites don't
need to be careful with NULL pointers any more.
Sami Vaarala