The code_state.old_globals variable is there to save the globals state so
should be used for this purpose, to avoid the need for additional local
variables on the C stack.
Without this, if GC threshold is hit and there is not enough memory left to
satisfy the request, gc_collect() will run a second time and the search for
memory will happen again and will fail again.
Thanks to @adritium for pointing out this issue, see #3786.
Under ubsan, when evaluating hash(-0.) the following diagnostic occurs:
../../py/objfloat.c:102:15: runtime error: negation of
-9223372036854775808 cannot be represented in type 'mp_int_t' (aka
'long'); cast to an unsigned type to negate this value to itself
So do just that, to tell the compiler that we want to perform this
operation using modulo arithmetic rules.
Before this, ubsan would detect a problem when executing
hash(006699999999999999999999999999999999999999999999999999999999999999999999)
../../py/mpz.c:1539:20: runtime error: left shift of 1067371580458 by
32 places cannot be represented in type 'mp_int_t' (aka 'long')
When the overflow does occur it now happens as defined by the rules of
unsigned arithmetic.
When computing e.g. hash(0.4e3) with ubsan enabled, a diagnostic like the
following would occur:
../../py/objfloat.c:91:30: runtime error: shift exponent 44 is too
large for 32-bit type 'int'
By casting constant "1" to the right type the intended value is preserved.
Fuzz testing combined with the undefined behavior sanitizer found that
parsing unreasonable float literals like 1e+9999999999999 resulted in
undefined behavior due to overflow in signed integer arithmetic, and a
wrong result being returned.
There is no need to use the mp_int_t type which may be 64-bits wide, there
is enough bit-width in a normal int to parse reasonable exponents. Using
int helps to reduce code size for 64-bit ports, especially nan-boxing
builds. (Similarly for the "dig" variable which is now an unsigned int.)
Calling memset(NULL, value, 0) is not standards compliant so we must add an
explicit check that emit->label_offsets is indeed not NULL before calling
memset (this pointer will be NULL on the first pass of the parse tree and
it's more logical / safer to check this pointer rather than check that the
pass is not the first one).
Code sanitizers will warn if NULL is passed as the first value to memset,
and compilers may optimise the code based on the knowledge that any pointer
passed to memset is guaranteed not to be NULL.
Before this patch:
>>> print(')
... ')
Traceback (most recent call last):
File "<stdin>", line 1
SyntaxError: invalid syntax
After this patch:
>>> print(')
Traceback (most recent call last):
File "<stdin>", line 1
SyntaxError: invalid syntax
This matches CPython and prevents getting stuck in REPL continuation when a
1-quote is unmatched.
Before this patch, when using the switch statement for dispatch in the VM
(not computed goto) a pending exception check was done after each opcode.
This is not necessary and this patch makes the pending exception check only
happen when explicitly requested by certain opcodes, like jump. This
improves performance of the VM by about 2.5% when using the switch.
This patch fixes the macro so you can pass any name in, and the macro will
make more sense if you're reading it on its own. It worked previously
because n_state is always passed in as n_state_out_var.
gcc 8.0 supports the naked attribute for x86 systems so it can now be used
here. And in fact it is necessary to use this for nlr_push because gcc 8.0
no longer generates a prelude for this function (even without the naked
attribute).
This patch moves the start of the root pointer section in mp_state_ctx_t
so that it skips entries that are not pointers and don't need scanning.
Previously, the start of the root pointer section was at the very beginning
of the mp_state_ctx_t struct (which is the beginning of mp_state_thread_t).
This was the original assembler version of the NLR code was hard-coded to
have the nlr_top pointer at the start of this state structure. But now
that the NLR code is partially written in C there is no longer this
restriction on the location of nlr_top (and a comment to this effect has
been removed in this patch).
So now the root pointer section starts part way through the
mp_state_thread_t structure, after the entries which are not root pointers.
This patch also moves the non-pointer entries for MICROPY_ENABLE_SCHEDULER
outside the root pointer section.
Moving non-pointer entries out of the root pointer section helps to make
the GC more precise and should help to prevent some cases of collectable
garbage being kept.
This patch also has a measurable improvement in performance of the
pystone.py benchmark: on unix x86-64 and stm32 there was an improvement of
roughly 0.6% (tested with both gcc 7.3 and gcc 8.1).
This patch changes 2 things in the endianness detection:
1. Don't assume that __BYTE_ORDER__ not being __ORDER_LITTLE_ENDIAN__ means
that the machine is big endian, so add an explicit check that this macro
is indeed __ORDER_BIG_ENDIAN__ (same with __BYTE_ORDER, __LITTLE_ENDIAN
and __BIG_ENDIAN). A machine could have PDP endianness.
2. Remove the checks which base their autodetection decision on whether any
little or big endian macros are defined (eg __LITTLE_ENDIAN__ or
__BIG_ENDIAN__). Just because a system defines these does not mean it
has that endianness.
See issue #3760.
For cases where size_t is smaller than mp_int_t (eg nan-boxing builds) the
difference between two size_t's is not sign extended into mp_int_t and so
the result is never negative. This patch fixes this bug by using ssize_t
for the type of the result.
This gives dir() better behaviour when listing the attributes of a user
type that defines __getattr__: it will now not list those attributes for
which __getattr__ raises AttributeError (meaning the attribute is not
supported by the object).
This patch fixes the possibility of a crash of the REPL when tab-completing
an object which raises an exception when its attributes are accessed.
See issue #3729.
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.
This is a more consistent use of errno codes. For example, it may be that
a stream returns MP_EAGAIN but the mp_is_nonblocking_error() macro doesn't
catch this value because it checks for EAGAIN instead (which may have a
different value than MP_EAGAIN when MICROPY_USE_INTERNAL_ERRNO is enabled).
Most modern systems have EWOULDBLOCK aliased to EAGAIN, ie they have the
same value. But some systems use different values for these errnos and if
a uPy port is using the system errno values (ie not the internal uPy
values) then it's important to be able to distinguish EWOULDBLOCK from
EAGAIN. Eg if a system call returned EWOULDBLOCK it must be possible to
check for this return value, and this patch makes this now possible.
Instead of emitnative.c having configuration code for each supported
architecture, and then compiling this file multiple times with different
macros defined, this patch adds a file per architecture with the necessary
code to configure the native emitter. These files then #include the
emitnative.c file.
This simplifies emitnative.c (which is already very large), and simplifies
the build system because emitnative.c no longer needs special handling for
compilation and qstr extraction.
This patch moves the implementation of stream closure from a dedicated
method to the ioctl of the stream protocol, for each type that implements
closing. The benefits of this are:
1. Rounds out the stream ioctl function, which already includes flush,
seek and poll (among other things).
2. Makes calling mp_stream_close() on an object slightly more efficient
because it now no longer needs to lookup the close method and call it,
rather it just delegates straight to the ioctl function (if it exists).
3. Reduces code size and allows future types that implement the stream
protocol to be smaller because they don't need a dedicated close method.
Code size reduction is around 200 bytes smaller for x86 archs and around
30 bytes smaller for the bare-metal archs.
The LHS passed to mp_obj_int_binary_op() will always be an integer, either
a small int or a big int, so the test for this type doesn't need to include
an "other, unsupported type" case.
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.
When pystack is enabled mp_obj_fun_bc_prepare_codestate() will always
return a valid pointer, and if there is no more pystack available then it
will raise an exception (a RuntimeError). So having pystack enabled with
stackless enabled automatically gives strict stackless mode. There is
therefore no need to have code for strict stackless mode when pystack is
enabled, and this patch optimises the VM for such a case.
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.
By using pre-compiled regexs, using startswith(), and explicitly checking
for empty lines (of which around 30% of the input lines are), automatic
qstr extraction is speed up by about 10%.
All callers of mp_obj_int_formatted() are expected to pass in a valid int
object, and they do:
- mp_obj_int_print() should always pass through an int object because it is
the print special method for int instances.
- mp_print_mp_int() checks that the argument is an int, and if not converts
it to a small int.
This patch saves around 20-50 bytes of code space.
Prior to this patch, some architectures (eg unix x86) could render floats
with "negative" digits, like ")". For example, '%.23e' % 1e-80 would come
out as "1.0000000000000000/)/(,*0e-80". This patch fixes the known cases.
Prior to this patch, some architectures (eg unix x86) could render floats
with a ":" character in them, eg 1e+39 would come out as ":e+38" (":" is
just after "9" in ASCII so this is like 10e+38). This patch fixes some of
these cases.
Prior to this patch the %f formatting of some FP values could be off by up
to 1, eg '%.0f' % 123 would return "122" (unix x64). Depending on the FP
precision (single vs double) certain numbers would format correctly, but
others wolud not. This patch should fix all cases of rounding for %f.
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).
This patch concerns the handling of an NLR-raised StopIteration, raised
during a call to mp_resume() which is handling the yield from opcode.
Previously, commit 6738c1dded introduced code
to handle this case, along with a test. It seems that it was lucky that
the test worked because the code did not correctly handle the stack pointer
(sp).
Furthermore, commit 79d996a57b improved the
way mp_resume() propagated certain exceptions: it changed raising an NLR
value to returning MP_VM_RETURN_EXCEPTION. This change meant that the
test introduced in gen_yield_from_ducktype.py was no longer hitting the
code introduced in 6738c1dded.
The patch here does two things:
1. Fixes the handling of sp in the VM for the case that yield from is
interrupted by a StopIteration raised via NLR.
2. Introduces a new test to check this handling of sp and re-covers the
code in the VM.
This path for src->deg==NULL is never used because mpz_clone() is always
called with an argument that has a non-zero integer value, and hence has
some digits allocated to it (mpz_clone() is a static function private to
mpz.c all callers of this function first check if the integer value is zero
and if so take a special-case path, bypassing the call to mpz_clone()).
There is some unused and commented-out functions that may actually pass a
zero-valued mpz to mpz_clone(), so some TODOs are added to these function
in case they are needed in the future.
All callers of the asm entry function guarantee that num_locals>=0, so no
need to add an explicit check for it. Use an assertion instead.
Also, the signature of asm_x86_entry is changed to match the other asm
entry functions.
If a port only needs the core files then it can now use the $(PY_CORE_O)
variable instead of $(PY_O). $(PY_EXTMOD_O) contains the list of extmod
files (including some files from lib/). $(PY_O) retains its original
definition as the list of all object file (including those for frozen code)
and is a convenience variable for ports that want everything.
Saves a few bytes of code space, and is more efficient because with
MICROPY_GC_CONSERVATIVE_CLEAR enabled by default all memory is already
cleared when allocated.
Otherwise passing -1 as maxlen will lead to a zero allocation and
subsequent unbound buffer overflow in deque.append() because i_put is
allowed to grow without bound.
So far, implements just append() and popleft() methods, required for
a normal queue. Constructor doesn't accept an arbitarry sequence to
initialize from (am empty deque is always created), so an empty tuple
must be passed as such. Only fixed-size deques are supported, so 2nd
argument (size) is required.
There's also an extension to CPython - if True is passed as 3rd argument,
append(), instead of silently overwriting the oldest item on queue
overflow, will throw IndexError. This behavior is desired in many
cases, where queues should store information reliably, instead of
silently losing some items.
The micropython.stack_use() function is useful to query the current C stack
usage, and it's inclusion in the micropython module doesn't need to be tied
to the inclusion of mem_info()/qstr_info() because it doesn't rely on any
of the code from these functions. So this patch introduces the config
option MICROPY_PY_MICROPYTHON_STACK_USE which can be used to independently
control the inclusion of stack_use(). By default it is enabled if
MICROPY_PY_MICROPYTHON_MEM_INFO is enabled (thus not changing any of the
existing ports).
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.
Prior to this patch uPy (on a 32-bit arch) would have severe issues when
calling bytes(-1): such a call would call vstr_init_len(vstr, -1) which
would then +1 on the len and call vstr_init(vstr, 0), which would then
round this up and allocate a small amount of memory for the vstr. The
bytes constructor would then attempt to zero out all this memory, thinking
it had allocated 2^32-1 bytes.
This patch changes the way REPL autocomplete finds matches. It now probes
the target object for all qstrs via mp_load_method_maybe to look for a
match with the given input string. Similar to how the builtin dir()
function works, this new algorithm now find all methods and instances of
user-defined classes including attributes of their parent classes. This
helps a lot at the REPL prompt for user-discovery and to autocomplete names
even for classes that are derived.
The downside is that this new algorithm is slower than the previous one,
and in particular will be slower the more qstrs there are in the system.
But because REPL autocomplete is primarily used in an interactive way it is
not that important to make it fast, as long as it is "fast enough" compared
to human reaction.
On a slow microcontroller (CPU running at 16MHz) the autocomplete time for
a list of 35 names in the outer namespace (pressing tab at a bare prompt)
takes about 160ms with this algorithm, compared to about 40ms for the
previous implementation (this time includes the actual printing of the
names as well). This time of 160ms is very reasonable especially given the
new functionality of listing all the names.
This patch also decreases code size by:
bare-arm: +0
minimal x86: -128
unix x64: -128
unix nanbox: -224
stm32: -88
cc3200: -80
esp8266: -92
esp32: -84
This patch improves the builtin dir() function by probing the target object
with all possible qstrs via mp_load_method_maybe. This is very simple (in
terms of implementation), doesn't require recursion, and allows to list all
methods of user-defined classes (without duplicates) even if they have
multiple inheritance with a common parent. The downside is that it can be
slow because it has to iterate through all the qstrs in the system, but
the "dir()" function is anyway mostly used for testing frameworks and user
introspection of types, so speed is not considered a priority.
In addition to providing a more complete implementation of dir(), this
patch is simpler than the previous implementation and saves some code
space:
bare-arm: -80
minimal x86: -80
unix x64: -56
unix nanbox: -48
stm32: -80
cc3200: -80
esp8266: -104
esp32: -64
This macro is written out explicitly in the two locations that it is used
and then the code is optimised, opening possibilities for further
optimisations and reducing code size:
unix: -48
minimal CROSS=1: -32
stm32: -32
Using the message "maximum recursion depth exceeded" for when the pystack
runs out of memory can be misleading because the pystack can run out for
reasons other than deep recursion (although in most cases pystack
exhaustion is probably indirectly related to deep recursion). And it's
important to give the user more precise feedback as to the reason for the
error: if they know precisely that the pystack was exhausted then they have
a chance to increase the amount of memory available to the pystack (as
opposed to not knowing if it was the C stack or pystack that ran out).
Also, C stack exhaustion is more serious than pystack exhaustion because it
could have been that the C stack overflowed and overwrote/corrupted some
data and so the system must be restarted. The pystack can never corrupt
data in this way so pystack exhaustion does not require a system restart.
Knowing the difference between these two cases is therefore important.
The actual exception type for pystack exhaustion remains as RuntimeError so
that programatically it behaves the same as a C stack exhaustion.
By adding __builtin_unreachable() at the end of nlr_push, we're
essentially telling the compiler that this function will never return.
When GCC LTO is in use, this means that any time nlr_push() is called
(which is often), the compiler thinks this function will never return
and thus eliminates all code following the call.
Note: I've added a 'return 0' for older GCC versions like 4.6 which
complain about not returning anything (which doesn't make sense in a
naked function). Newer GCC versions (tested 4.8, 5.4 and some others)
don't complain about this.
This constant exception instance was once used by m_malloc_fail() to raise
a MemoryError without allocating memory, but it was made obsolete long ago
by 3556e45711. The functionality is now
replaced by the use of mp_emergency_exception_obj which lives in the global
uPy state, and which can handle any exception type, not just MemoryError.
This feature is not often used so is guarded by the config option
MICROPY_PY_BUILTINS_RANGE_BINOP which is disabled by default. With this
option disabled MicroPython will always return false when comparing two
range objects for equality (unless they are exactly the same object
instance). This does not match CPython so if (in)equality between range
objects is needed then this option should be enabled.
Enabling this option costs between 100 and 200 bytes of code space
depending on the machine architecture.
This patch provides inline versions of the utf8 helper functions for the
case when unicode is disabled (MICROPY_PY_BUILTINS_STR_UNICODE set to 0).
This saves code size.
The unichar_charlen function is also renamed to utf8_charlen to match the
other utf8 helper functions, and the signature of this function is adjusted
for consistency (const char* -> const byte*, mp_uint_t -> size_t).
Prior to this patch, a float literal that was close to subnormal would
have a loss of precision when parsed. The worst case was something like
float('10000000000000000000e-326') which returned 0.0.
This patch simplifies how sentinel values are stored on the stack when
doing an unwind return or jump. Instead of storing two values on the stack
for an unwind jump it now stores only one: a negative small integer means
unwind-return and a non-negative small integer means unwind-jump with the
value being the number of exceptions to unwind. The savings in code size
are:
bare-arm: -56
minimal x86: -68
unix x64: -80
unix nanbox: -4
stm32: -56
cc3200: -64
esp8266: -76
esp32: -156
The array should be of type unsigned byte because that is the type of the
values being stored. And changing to uint8_t helps to prevent warnings
from some static analysers.
Note that the check for elem!=NULL is removed for the
MP_MAP_LOOKUP_ADD_IF_NOT_FOUND case because mp_map_lookup will always
return non-NULL for such a case.
This patch combines the compiler optimisation code for double and triple
tuple-to-tuple assignment, taking it from two separate if-blocks to one
combined if-block. This can be done because the code for both of these
optimisations has a lot in common. Combining them together reduces code
size for ports that have the triple-tuple optimisation enabled (and doesn't
change code size for ports that have it disabled).
Damien George
Jan Klusacek
Jeff Epler
Li Weiwei
Tom Collins
Ayke van Laethem
Paul Sokolovsky
Mike Wadsten
stijn