In which case place the native function prelude in a bytes object, linked
from the const_table of that function. An architecture should define
N_PRELUDE_AS_BYTES_OBJ to 1 before including py/emitnative.c to emit
correct machine code, then enable MICROPY_EMIT_NATIVE_PRELUDE_AS_BYTES_OBJ
so the runtime can correctly handle the prelude being in a bytes object.
Such that args/return regs for the parent are different to args/return regs
for child calls. For an architecture to use this feature it should define
the REG_PARENT_xxx macros before including py/emitnative.c.
Prior to this commit, when unwinding through an active finally the stack
was not being correctly popped/folded, which resulting in the VM crashing
for complicated unwinding of nested finallys.
This should be fixed with this commit, and more tests for return/break/
continue within a finally have been added to exercise this.
As of 7d58a197cf, `NULL` should no longer be
here because it's allowed (MP_QSTRnull took its place). This entry was
preventing the use of MP_QSTR_NULL to mean "NULL" (although this is not
currently used).
A blacklist should not be needed because it should be possible to intern
all strings.
Fixes issue #5140.
This check follows CPython's behaviour, because 'import *' always populates
the globals with the imported names, not locals.
Since it's safe to do this (doesn't lead to a crash or undefined behaviour)
the check is only enabled for MICROPY_CPYTHON_COMPAT.
Fixes issue #5121.
This patch compresses the second part of the bytecode prelude which
contains the source file name, function name, source-line-number mapping
and cell closure information. This part of the prelude now begins with a
single varible length unsigned integer which encodes 2 numbers, being the
byte-size of the following 2 sections in the header: the "source info
section" and the "closure section". After decoding this variable unsigned
integer it's possible to skip over one or both of these sections very
easily.
This scheme saves about 2 bytes for most functions compared to the original
format: one in the case that there are no closure cells, and one because
padding was eliminated.
The start of the bytecode prelude contains 6 numbers telling the amount of
stack needed for the Python values and exceptions, and the signature of the
function. Prior to this patch these numbers were all encoded one after the
other (2x variable unsigned integers, then 4x bytes), but using so many
bytes is unnecessary.
An entropy analysis of around 150,000 bytecode functions from the CPython
standard library showed that the optimal Shannon coding would need about
7.1 bits on average to encode these 6 numbers, compared to the existing 48
bits.
This patch attempts to get close to this optimal value by packing the 6
numbers into a single, varible-length unsigned integer via bit-wise
interleaving. The interleaving scheme is chosen to minimise the average
number of bytes needed, and at the same time keep the scheme simple enough
so it can be implemented without too much overhead in code size or speed.
The scheme requires about 10.5 bits on average to store the 6 numbers.
As a result most functions which originally took 6 bytes to encode these 6
numbers now need only 1 byte (in 80% of cases).
From the beginning of this project the RAISE_VARARGS opcode was named and
implemented following CPython, where it has an argument (to the opcode)
counting how many args the raise takes:
raise # 0 args (re-raise previous exception)
raise exc # 1 arg
raise exc from exc2 # 2 args (chained raise)
In the bytecode this operation therefore takes 2 bytes, one for
RAISE_VARARGS and one for the number of args.
This patch splits this opcode into 3, where each is now a single byte.
This reduces bytecode size by 1 byte for each use of raise. Every byte
counts! It also has the benefit of reducing code size (on all ports except
nanbox).
To make progress towards MicroPython supporting Python 3.5, adding the
matmul operator is important because it's a really "low level" part of the
language, being a new token and modifications to the grammar.
It doesn't make sense to make it configurable because 1) it would make the
grammar and lexer complicated/messy; 2) no other operators are
configurable; 3) it's not a feature that can be "dynamically plugged in"
via an import.
And matmul can be useful as a general purpose user-defined operator, it
doesn't have to be just for numpy use.
Based on work done by Jim Mussared.
Prior to this patch mp_opcode_format would calculate the incorrect size of
the MP_BC_UNWIND_JUMP opcode, missing the additional byte. But, because
opcodes below 0x10 are unused and treated as bytes in the .mpy load/save
and freezing code, this bug did not show any symptoms, since nested unwind
jumps would rarely (if ever) reach a depth of 16 (so the extra byte of this
opcode would be between 0x01 and 0x0f and be correctly loaded/saved/frozen
simply as an undefined opcode).
This patch fixes this bug by correctly accounting for the additional byte.
.
With this patch alignment is done relative to the start of the buffer that
is being unpacked, not the raw pointer value, as per CPython.
Fixes issue #3314.
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.
Prior to this patch the line number for a lambda would be "line 1" if the
body of the lambda contained only a simple expression (with no line number
stored in the parse node). Now the line number is always reported
correctly.
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.
With this patch exceptions that are re-raised have improved tracebacks
(less confusing, match CPython), and it makes re-raise slightly more
efficient (in time and RAM) because they no longer need to add a traceback.
Also general VM performance is not measurably affected.
Partially fixes issue #2928.
With this patch exception tracebacks that go through a finally are improved
(less confusing, match CPython), and it makes finally's slightly more
efficient (in time and RAM) because they no longer need to add a traceback.
Partially fixes issue #2928.
Damien George