I.e. in this mode, C stack will never be used to call a Python function,
but if there's no free heap for a call, it will be reported as
RuntimeError (as expected), not MemoryError.
Given that there's already support for "fixed table" maps, which are
essentially ordered maps, the implementation of OrderedDict just extends
"fixed table" maps by adding an "is ordered" flag and add/remove
operations, and reuses 95% of objdict code, just making methods tolerant
to both dict and OrderedDict.
Some things are missing so far, like CPython-compatible repr and comparison.
OrderedDict is Disabled by default; enabled on unix and stmhal ports.
These allow to fine-tune the compiler to select whether it optimises
tuple assignments of the form a, b = c, d and a, b, c = d, e, f.
Sensible defaults are provided.
This is rarely used feature which takes enough code to implement, so is
controlled by MICROPY_PY_ARRAY_SLICE_ASSIGN config setting, default off.
But otherwise it may be useful, as allows to update arbitrary-sized data
buffers in-place.
Slice is yet to implement, and actually, slice assignment implemented in
such a way that RHS of assignment should be array of the exact same item
typecode as LHS. CPython has it more relaxed, where RHS can be any sequence
of compatible types (e.g. it's possible to assign list of int's to a
bytearray slice).
Overall, when all "slice write" features are implemented, it may cost ~1KB
of code.
The implementation of these functions is very large (order 4k) and they
are rarely used, so we don't enable them by default.
They are however enabled in stmhal and unix, since we have the room.
pyexec_friendly_repl_process_char() and friends, useful for ports which
integrate into existing cooperative multitasking system.
Unlike readline() refactor before, this was implemented in less formal,
trial&error process, minor functionality regressions are still known
(like soft&hard reset support). So, original loop-based pyexec_friendly_repl()
is left intact, specific implementation selectable by config setting.
Native code has GC-heap pointers in it so it must be scanned. But on
unix port memory for native functions is mmap'd, and so it must have
explicit code to scan it for root pointers.
This new config option sets how many fixed-number-of-bytes to use to
store the length of each qstr. Previously this was hard coded to 2,
but, as per issue #1056, this is considered overkill since no-one
needs identifiers longer than 255 bytes.
With this patch the number of bytes for the length is configurable, and
defaults to 1 byte. The configuration option filters through to the
makeqstrdata.py script.
Code size savings going from 2 to 1 byte:
- unix x64 down by 592 bytes
- stmhal down by 1148 bytes
- bare-arm down by 284 bytes
Also has RAM savings, and will be slightly more efficient in execution.
Compiler optimises lookup of module.CONST when enabled (an existing
feature). Disabled by default; enabled for unix, windows, stmhal.
Costs about 100 bytes ROM on stmhal.
This allows to enable mem-info functions in micropython module, even if
MICROPY_MEM_STATS is not enabled. In this case, you get mem_info and
qstr_info but not mem_{total,current,peak}.
This is a simple optimisation inspired by JITing technology: we cache in
the bytecode (using 1 byte) the offset of the last successful lookup in
a map. This allows us next time round to check in that location in the
hash table (mp_map_t) for the desired entry, and if it's there use that
entry straight away. Otherwise fallback to a normal map lookup.
Works for LOAD_NAME, LOAD_GLOBAL, LOAD_ATTR and STORE_ATTR opcodes.
On a few tests it gives >90% cache hit and greatly improves speed of
code.
Disabled by default. Enabled for unix and stmhal ports.
This patch consolidates all global variables in py/ core into one place,
in a global structure. Root pointers are all located together to make
GC tracing easier and more efficient.
This patch adds a configuration option (MICROPY_CAN_OVERRIDE_BUILTINS)
which, when enabled, allows to override all names within the builtins
module. A builtins override dict is created the first time the user
assigns to a name in the builtins model, and then that dict is searched
first on subsequent lookups. Note that this implementation doesn't
allow deleting of names.
This patch also does some refactoring of builtins code, creating the
modbuiltins.c file.
Addresses issue #959.
Going from MICROPY_ERROR_REPORTING_NORMAL to
MICROPY_ERROR_REPORTING_TERSE now saves 2020 bytes ROM for ARM Thumb2,
and 2200 bytes ROM for 32-bit x86.
This is about a 2.5% code size reduction for bare-arm.
With this patch a port can enable module weak link support and provide
a dict of qstr->module mapping. This mapping is looked up only if an
import fails to find the requested module in the filesystem.
This allows to have the builtin module named, eg, usocket, and provide
a weak link of "socket" to the same module, but this weak link can be
overridden if a file by the name "socket.py" is found in the import
path.
Type representing signed size doesn't have to be int, so use special value
which defaults to SSIZE_MAX, but as it's not defined by C standard (but rather
by POSIX), allow ports to set it.
Because (for Thumb) a function pointer has the LSB set, pointers to
dynamic functions in RAM (eg native, viper or asm functions) were not
being traced by the GC. This patch is a comprehensive fix for this.
Addresses issue #820.
The user code should call micropython.alloc_emergency_exception_buf(size)
where size is the size of the buffer used to print the argument
passed to the exception.
With the test code from #732, and a call to
micropython.alloc_emergenncy_exception_buf(100) the following error is
now printed:
```python
>>> import heartbeat_irq
Uncaught exception in Timer(4) interrupt handler
Traceback (most recent call last):
File "0://heartbeat_irq.py", line 14, in heartbeat_cb
NameError: name 'led' is not defined
```
Such mechanism is important to get stable Python functioning, because Python
function calling is handled with C stack. The idea is to sprinkle
STACK_CHECK() calls in places where there can be C recursion.
TODO: Add more STACK_CHECK()'s.
This completes non-automatic interning of strings in the parser, so that
doc strings don't take up RAM. It complicates the parser and compiler,
and bloats stmhal by about 300 bytes. It's complicated because now
there are 2 kinds of parse-nodes that can be strings: interned leaves
and non-interned structs.
io.FileIO is binary I/O, ans actually optional. Default file type is
io.TextIOWrapper, which provides str results. CPython3 explicitly describes
io.TextIOWrapper as buffered I/O, but we don't have buffering support yet
anyway.
You can now do:
X = const(123)
Y = const(456 + X)
and the compiler will replace X and Y with their values.
See discussion in issue #266 and issue #573.
There are 2 locations in parser, and 1 in compiler, where memory
allocation is not precise. In the parser it's the rule stack and result
stack, in the compiler it's the array for the identifiers in the current
scope. All other mallocs are exact (ie they don't allocate more than is
needed).
This patch adds tuning options (MP_ALLOC_*) to mpconfig.h for these 3
inexact allocations.
The inexact allocations in the parser should actually be close to
logarithmic: you need an exponentially larger script (absent pathological
cases) to use up more room on the rule and result stacks. As such, the
default allocation policy for these is now to start with a modest sized
stack, but grow only in small increments.
For the identifier arrays in the compiler, these now start out quite
small (4 entries, since most functions don't have that many ids), and
grow incrementally by 6 (since if you have more ids than 4, you probably
have quite a few more, but it wouldn't be exponentially more).
Partially addresses issue #560.
Blanket wide to all .c and .h files. Some files originating from ST are
difficult to deal with (license wise) so it was left out of those.
Also merged modpyb.h, modos.h, modstm.h and modtime.h in stmhal/.
On stmhal, computed gotos make the binary about 1k bigger, but makes it
run faster, and we have the room, so why not. All tests pass on
pyboard using computed gotos.
