This commit implements a more complete replication of CPython's behaviour
for equality and inequality testing of objects. This addresses the issues
discussed in #5382 and a few other inconsistencies. Improvements over the
old code include:
- Support for returning non-boolean results from comparisons (as used by
numpy and others).
- Support for non-reflexive equality tests.
- Preferential use of __ne__ methods and MP_BINARY_OP_NOT_EQUAL binary
operators for inequality tests, when available.
- Fallback to op2 == op1 or op2 != op1 when op1 does not implement the
(in)equality operators.
The scheme here makes use of a new flag, MP_TYPE_FLAG_NEEDS_FULL_EQ_TEST,
in the flags word of mp_obj_type_t to indicate if various shortcuts can or
cannot be used when performing equality and inequality tests. Currently
four built-in classes have the flag set: float and complex are
non-reflexive (since nan != nan) while bytearray and frozenszet instances
can equal other builtin class instances (bytes and set respectively). The
flag is also set for any new class defined by the user.
This commit also includes a more comprehensive set of tests for the
behaviour of (in)equality operators implemented in special methods.
This moves the MICROPY_PORT_INIT_FUNC hook to the end of mp_init(), just
before MP_THREAD_GIL_ENTER(), so that everything (in particular the GIL
mutex) is intialized before the hook is called. MICROPY_PORT_DEINIT_FUNC
is also moved to be symmetric (but there is no functional change there).
If a port needs to perform initialisation earlier than
MICROPY_PORT_INIT_FUNC then it can do it before calling mp_init().
Most types are in rodata/ROM, and mp_obj_base_t.type is a constant pointer,
so enforce this const-ness throughout the code base. If a type ever needs
to be modified (eg a user type) then a simple cast can be used.
A user-defined type that defines __iter__ doesn't need any memory to be
pre-allocated for its iterator (because it can't use such memory). So
optimise for this case by not allocating the iter-buf.
Allows assigning attributes on class instances that implement their own
__setattr__. Both object.__setattr__ and super(A, b).__setattr__ will work
with this commit.
runtime0.h is part of the MicroPython ABI so it's simpler if it's
independent of config options, like MICROPY_PY_REVERSE_SPECIAL_METHODS.
What's effectively done here is to move MP_BINARY_OP_DIVMOD and
MP_BINARY_OP_CONTAINS up in the enum, then remove the #if
MICROPY_PY_REVERSE_SPECIAL_METHODS conditional.
Without this change .mpy files would need to have a feature flag for
MICROPY_PY_REVERSE_SPECIAL_METHODS (when embedding native code that uses
this enum).
This commit has no effect when MICROPY_PY_REVERSE_SPECIAL_METHODS is
disabled. With this option enabled this commit reduces code size by about
60 bytes.
This commit adds support for sys.settrace, allowing to install Python
handlers to trace execution of Python code. The interface follows CPython
as closely as possible. The feature is disabled by default and can be
enabled via MICROPY_PY_SYS_SETTRACE.
mp_compile no longer takes an emit_opt argument, rather this setting is now
provided by the global default_emit_opt variable.
Now, when -X emit=native is passed as a command-line option, the emitter
will be set for all compiled modules (included imports), not just the
top-level script.
In the future there could be a way to also set this variable from a script.
Fixes issue #4267.
This patch implements a new sys.atexit function which registers a function
that is later executed when the main script ends. It is configurable via
MICROPY_PY_SYS_ATEXIT, disabled by default.
This is not compliant with CPython, rather it can be used to implement a
CPython compatible "atexit" module if desired (similar to how
sys.print_exception can be used to implement functionality of the
"traceback" module).
This patch adds a simple but powerful hook into the import system, in a
CPython compatible way, by allowing to override builtins.__import__.
This does introduce some overhead to all imports but it's minor:
- the dict lookup of __import__ is bypassed if there are no modifications
to the builtins module (which is the case at start up);
- imports are not performance critical, usually done just at the start of a
script;
- compared to how much work is done in an import, looking up a value in a
dict is a relatively small additional piece of work.
Prior to this commit, building the unix port with `DEBUG=1` and
`-finstrument-functions` the compilation would fail with an error like
"control reaches end of non-void function". This change fixes this by
removing the problematic "if (0)" branches. Not all branches affect
compilation, but they are all removed for consistency.
These macros could in principle be (inline) functions so it makes sense to
have them lower case, to match the other C API functions.
The remaining macros that are upper case are:
- MP_OBJ_TO_PTR, MP_OBJ_FROM_PTR
- MP_OBJ_NEW_SMALL_INT, MP_OBJ_SMALL_INT_VALUE
- MP_OBJ_NEW_QSTR, MP_OBJ_QSTR_VALUE
- MP_OBJ_FUN_MAKE_SIG
- MP_DECLARE_CONST_xxx
- MP_DEFINE_CONST_xxx
These must remain macros because they are used when defining const data (at
least, MP_OBJ_NEW_SMALL_INT is so it makes sense to have
MP_OBJ_SMALL_INT_VALUE also a macro).
For those macros that have been made lower case, compatibility macros are
provided for the old names so that users do not need to change their code
immediately.
There was an assumption that all names in a module dict are qstr's.
However, they can be dynamically generated (by assigning to globals()),
and in case of a long name, it won't be a qstr. Handle this situation
properly, including taking care of not creating superfluous qstr's for
names starting with "_" (which aren't imported by "import *").
And remove related comment about needing such protection when calling send.
Reasoning for removal is as follows:
- mp_resume is only called by the VM in YIELD_FROM opcode
- if send_value != MP_OBJ_NULL then throw_value == MP_OBJ_NULL
- so if __next__ or send are called then throw_value == MP_OBJ_NULL
- if __next__ or send raise an exception without nlr protection then the
exception will be handled by the global exception handler of the VM
- this handler already has code to handle exceptions raised in YIELD_FROM,
including correct handling of StopIteration
- this handler doesn't handle the case of injection of GeneratorExit, but
this won't be needed because throw_value == MP_OBJ_NULL
Note that it's already possible for mp_resume() to raise an exception
(including StopIteration) from the unprotected call to type->iternext(), so
that's why the VM already has code to handle the case of exceptions coming
out of mp_resume().
This commit reduces code size by a bit, and significantly reduces C stack
usage when using yield-from, from 88 bytes down to 40 for Thumb2, and 152
down to 72 bytes for x86-64 (better than half). (Note that gcc doesn't
seem to tail-call optimise the call from mp_resume() to mp_obj_gen_resume()
so this saving in C stack usage helps all uses of yield-from.)
There's no need to call mp_obj_new_int() which will just fail the check for
small int and call mp_obj_new_int_from_ll() anyway.
Thanks to @Jongy for prompting this change.
mp_obj_module_get_globals() returns a mp_obj_dict_t*, and type->locals_dict
is a mp_obj_dict_t*, so access the map entry of the dict directly instead
of needing to cast this mp_obj_dict_t* up to an object and then calling the
mp_obj_dict_get_map() helper function.
This patch changes dupterm to call the native C stream methods on the
connected stream objects, instead of calling the Python readinto/write
methods. This is much more efficient for native stream objects like UART
and webrepl and doesn't require allocating a special dupterm array.
This change is a minor breaking change from the user's perspective because
dupterm no longer accepts pure user stream objects to duplicate on. But
with the recent addition of uio.IOBase it is possible to still create such
classes just by inheriting from uio.IOBase, for example:
import uio, uos
class MyStream(uio.IOBase):
def write(self, buf):
# existing write implementation
def readinto(self, buf):
# existing readinto implementation
uos.dupterm(MyStream())
This new helper function acts like mp_load_method_maybe but is wrapped in
an NLR handler so it can catch exceptions. It prevents AttributeError from
propagating out, and optionally all other exceptions. This helper can be
used to fully implement hasattr (see follow-up commit), and also for cases
where mp_load_method_maybe is used but it must now raise an exception.
Without the compiler enabled the mp_optimise_value is unused, and the
micropython.opt_level() function is not useful, so exclude these from the
build to save RAM and code size.
The VM expects that, if mp_resume() returns MP_VM_RETURN_EXCEPTION, then
the returned value is an exception instance (eg to add a traceback to it).
It's possible that a value passed to a generator's throw() is not an
exception so must be explicitly checked for if the thrown value is not
intercepted by the generator.
Thanks to @jepler for finding the bug.
Prior to this patch the code would crash if a key in a ** dict was anything
other than a str or qstr. This is because mp_setup_code_state() assumes
that keys in kwargs are qstrs (for efficiency).
Thanks to @jepler for finding the bug.
There's no need to have MP_OBJ_NULL a special case, the code can re-use
the MP_OBJ_STOP_ITERATION value to signal the special case and the VM can
detect this with only one check (for MP_OBJ_STOP_ITERATION).
The new option is MICROPY_ENABLE_EXTERNAL_IMPORT and is enabled by default
so that the default behaviour is the same as before. With it disabled
import is only supported for built-in modules, not for external files nor
frozen modules. This allows to support targets that have no filesystem of
any kind and that only have access to pre-supplied built-in modules
implemented natively.
This patch introduces the MICROPY_ENABLE_PYSTACK option (disabled by
default) which enables a "Python stack" that allows to allocate and free
memory in a scoped, or Last-In-First-Out (LIFO) way, similar to alloca().
A new memory allocation API is introduced along with this Py-stack. It
includes both "local" and "nonlocal" LIFO allocation. Local allocation is
intended to be equivalent to using alloca(), whereby the same function must
free the memory. Nonlocal allocation is where another function may free
the memory, so long as it's still LIFO.
Follow-up patches will convert all uses of alloca() and VLA to the new
scoped allocation API. The old behaviour (using alloca()) will still be
available, but when MICROPY_ENABLE_PYSTACK is enabled then alloca() is no
longer required or used.
The benefits of enabling this option are (or will be once subsequent
patches are made to convert alloca()/VLA):
- Toolchains without alloca() can use this feature to obtain correct and
efficient scoped memory allocation (compared to using the heap instead
of alloca(), which is slower).
- Even if alloca() is available, enabling the Py-stack gives slightly more
efficient use of stack space when calling nested Python functions, due to
the way that compilers implement alloca().
- Enabling the Py-stack with the stackless mode allows for even more
efficient stack usage, as well as retaining high performance (because the
heap is no longer used to build and destroy stackless code states).
- With Py-stack and stackless enabled, Python-calling-Python is no longer
recursive in the C mp_execute_bytecode function.
The micropython.pystack_use() function is included to measure usage of the
Python stack.
Before this patch MP_BINARY_OP_IN had two meanings: coming from bytecode it
meant that the args needed to be swapped, but coming from within the
runtime meant that the args were already in the correct order. This lead
to some confusion in the code and comments stating how args were reversed.
It also lead to 2 bugs: 1) containment for a subclass of a native type
didn't work; 2) the expression "{True} in True" would illegally succeed and
return True. In both of these cases it was because the args to
MP_BINARY_OP_IN ended up being reversed twice.
To fix these things this patch introduces MP_BINARY_OP_CONTAINS which
corresponds exactly to the __contains__ special method, and this is the
operator that built-in types should implement. MP_BINARY_OP_IN is now only
emitted by the compiler and is converted to MP_BINARY_OP_CONTAINS by
swapping the arguments.
In mp_binary_op, there is no need to explicitly check for type->getiter
being non-null and raising an exception because this is handled exactly by
mp_getiter(). So just call the latter unconditionally.
The uos.dupterm() signature and behaviour is updated to reflect the latest
enhancements in the docs. It has minor backwards incompatibility in that
it no longer accepts zero arguments.
The dupterm_rx helper function is moved from esp8266 to extmod and
generalised to support multiple dupterm slots.
A port can specify multiple slots by defining the MICROPY_PY_OS_DUPTERM
config macro to an integer, being the number of slots it wants to have;
0 means to disable the dupterm feature altogether.
The unix and esp8266 ports are updated to work with the new interface and
are otherwise unchanged with respect to functionality.
Header files that are considered internal to the py core and should not
normally be included directly are:
py/nlr.h - internal nlr configuration and declarations
py/bc0.h - contains bytecode macro definitions
py/runtime0.h - contains basic runtime enums
Instead, the top-level header files to include are one of:
py/obj.h - includes runtime0.h and defines everything to use the
mp_obj_t type
py/runtime.h - includes mpstate.h and hence nlr.h, obj.h, runtime0.h,
and defines everything to use the general runtime support functions
Additional, specific headers (eg py/objlist.h) can be included if needed.
This allows user classes to implement __abs__ special method, and saves
code size (104 bytes for x86_64), even though during refactor, an issue
was fixed and few optimizations were made:
* abs() of minimum (negative) small int value is calculated properly.
* objint_longlong and objint_mpz avoid allocating new object is the
argument is already non-negative.
If, for class X, X.__add__(Y) doesn't exist (or returns NotImplemented),
try Y.__radd__(X) instead.
This patch could be simpler, but requires undoing operand swap and
operation switch to get non-confusing error message in case __radd__
doesn't exist.
Nicko van Someren
David Lechner
Damien George
Yonatan Goldschmidt
Jim Mussared
Milan Rossa
Paul m. p. P
Jun Wu
Andrew Leech
Paul Sokolovsky
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