Following how other objects work, set/frozenset methods should use the
mp_check_self() macro to check the type of the self argument, because in
most cases this check can be a null operation.
Saves about 100-180 bytes of code for builds with set and frozenset
enabled.
To reset the flags we should write to the single bit only, not the entire
register (otherwise all other settings in the register are cleared).
Fixes#2457.
Having a micropython.const identity function, and writing "from micropython
import const" at the start of scripts that use the const feature, allows to
write scripts which are compatible with CPython, and with uPy builds that
don't include const optimisation.
This patch adds such a function and updates the tests to do the import.
When an exception is raised and is to be handled by the VM, it is stored
on the Python value stack so the bytecode can access it. CPython stores
3 objects on the stack for each exception: exc type, exc instance and
traceback. uPy followed this approach, but it turns out not to be
necessary. Instead, it is enough to store just the exception instance on
the Python value stack. The only place where the 3 values are needed
explicitly is for the __exit__ handler of a with-statement context, but
for these cases the 3 values can be extracted from the single exception
instance.
This patch removes the need to store 3 values on the stack, and instead
just stores the exception instance.
Code size is reduced by about 50-100 bytes, the compiler and VM are
slightly simpler, generate bytecode is smaller (by 2 bytes for each try
block), and the Python value stack is reduced in size for functions that
handle exceptions.
This fixes constant substitution so that only standalone identifiers are
replaced with their constant value (if they have one). I.e. don't
replace NAME in expressions like obj.NAME or NAME = expr.
Damien George
Alex March
Paul Sokolovsky