Commit Graph

42 Commits

Author SHA1 Message Date
Damien George f2040bfc7e py: Rework bytecode and .mpy file format to be mostly static data.
Background: .mpy files are precompiled .py files, built using mpy-cross,
that contain compiled bytecode functions (and can also contain machine
code). The benefit of using an .mpy file over a .py file is that they are
faster to import and take less memory when importing.  They are also
smaller on disk.

But the real benefit of .mpy files comes when they are frozen into the
firmware.  This is done by loading the .mpy file during compilation of the
firmware and turning it into a set of big C data structures (the job of
mpy-tool.py), which are then compiled and downloaded into the ROM of a
device.  These C data structures can be executed in-place, ie directly from
ROM.  This makes importing even faster because there is very little to do,
and also means such frozen modules take up much less RAM (because their
bytecode stays in ROM).

The downside of frozen code is that it requires recompiling and reflashing
the entire firmware.  This can be a big barrier to entry, slows down
development time, and makes it harder to do OTA updates of frozen code
(because the whole firmware must be updated).

This commit attempts to solve this problem by providing a solution that
sits between loading .mpy files into RAM and freezing them into the
firmware.  The .mpy file format has been reworked so that it consists of
data and bytecode which is mostly static and ready to run in-place.  If
these new .mpy files are located in flash/ROM which is memory addressable,
the .mpy file can be executed (mostly) in-place.

With this approach there is still a small amount of unpacking and linking
of the .mpy file that needs to be done when it's imported, but it's still
much better than loading an .mpy from disk into RAM (although not as good
as freezing .mpy files into the firmware).

The main trick to make static .mpy files is to adjust the bytecode so any
qstrs that it references now go through a lookup table to convert from
local qstr number in the module to global qstr number in the firmware.
That means the bytecode does not need linking/rewriting of qstrs when it's
loaded.  Instead only a small qstr table needs to be built (and put in RAM)
at import time.  This means the bytecode itself is static/constant and can
be used directly if it's in addressable memory.  Also the qstr string data
in the .mpy file, and some constant object data, can be used directly.
Note that the qstr table is global to the module (ie not per function).

In more detail, in the VM what used to be (schematically):

    qst = DECODE_QSTR_VALUE;

is now (schematically):

    idx = DECODE_QSTR_INDEX;
    qst = qstr_table[idx];

That allows the bytecode to be fixed at compile time and not need
relinking/rewriting of the qstr values.  Only qstr_table needs to be linked
when the .mpy is loaded.

Incidentally, this helps to reduce the size of bytecode because what used
to be 2-byte qstr values in the bytecode are now (mostly) 1-byte indices.
If the module uses the same qstr more than two times then the bytecode is
smaller than before.

The following changes are measured for this commit compared to the
previous (the baseline):
- average 7%-9% reduction in size of .mpy files
- frozen code size is reduced by about 5%-7%
- importing .py files uses about 5% less RAM in total
- importing .mpy files uses about 4% less RAM in total
- importing .py and .mpy files takes about the same time as before

The qstr indirection in the bytecode has only a small impact on VM
performance.  For stm32 on PYBv1.0 the performance change of this commit
is:

diff of scores (higher is better)
N=100 M=100             baseline -> this-commit  diff      diff% (error%)
bm_chaos.py               371.07 ->  357.39 :  -13.68 =  -3.687% (+/-0.02%)
bm_fannkuch.py             78.72 ->   77.49 :   -1.23 =  -1.563% (+/-0.01%)
bm_fft.py                2591.73 -> 2539.28 :  -52.45 =  -2.024% (+/-0.00%)
bm_float.py              6034.93 -> 5908.30 : -126.63 =  -2.098% (+/-0.01%)
bm_hexiom.py               48.96 ->   47.93 :   -1.03 =  -2.104% (+/-0.00%)
bm_nqueens.py            4510.63 -> 4459.94 :  -50.69 =  -1.124% (+/-0.00%)
bm_pidigits.py            650.28 ->  644.96 :   -5.32 =  -0.818% (+/-0.23%)
core_import_mpy_multi.py  564.77 ->  581.49 :  +16.72 =  +2.960% (+/-0.01%)
core_import_mpy_single.py  68.67 ->   67.16 :   -1.51 =  -2.199% (+/-0.01%)
core_qstr.py               64.16 ->   64.12 :   -0.04 =  -0.062% (+/-0.00%)
core_yield_from.py        362.58 ->  354.50 :   -8.08 =  -2.228% (+/-0.00%)
misc_aes.py               429.69 ->  405.59 :  -24.10 =  -5.609% (+/-0.01%)
misc_mandel.py           3485.13 -> 3416.51 :  -68.62 =  -1.969% (+/-0.00%)
misc_pystone.py          2496.53 -> 2405.56 :  -90.97 =  -3.644% (+/-0.01%)
misc_raytrace.py          381.47 ->  374.01 :   -7.46 =  -1.956% (+/-0.01%)
viper_call0.py            576.73 ->  572.49 :   -4.24 =  -0.735% (+/-0.04%)
viper_call1a.py           550.37 ->  546.21 :   -4.16 =  -0.756% (+/-0.09%)
viper_call1b.py           438.23 ->  435.68 :   -2.55 =  -0.582% (+/-0.06%)
viper_call1c.py           442.84 ->  440.04 :   -2.80 =  -0.632% (+/-0.08%)
viper_call2a.py           536.31 ->  532.35 :   -3.96 =  -0.738% (+/-0.06%)
viper_call2b.py           382.34 ->  377.07 :   -5.27 =  -1.378% (+/-0.03%)

And for unix on x64:

diff of scores (higher is better)
N=2000 M=2000        baseline -> this-commit     diff      diff% (error%)
bm_chaos.py          13594.20 ->  13073.84 :  -520.36 =  -3.828% (+/-5.44%)
bm_fannkuch.py          60.63 ->     59.58 :    -1.05 =  -1.732% (+/-3.01%)
bm_fft.py           112009.15 -> 111603.32 :  -405.83 =  -0.362% (+/-4.03%)
bm_float.py         246202.55 -> 247923.81 : +1721.26 =  +0.699% (+/-2.79%)
bm_hexiom.py           615.65 ->    617.21 :    +1.56 =  +0.253% (+/-1.64%)
bm_nqueens.py       215807.95 -> 215600.96 :  -206.99 =  -0.096% (+/-3.52%)
bm_pidigits.py        8246.74 ->   8422.82 :  +176.08 =  +2.135% (+/-3.64%)
misc_aes.py          16133.00 ->  16452.74 :  +319.74 =  +1.982% (+/-1.50%)
misc_mandel.py      128146.69 -> 130796.43 : +2649.74 =  +2.068% (+/-3.18%)
misc_pystone.py      83811.49 ->  83124.85 :  -686.64 =  -0.819% (+/-1.03%)
misc_raytrace.py     21688.02 ->  21385.10 :  -302.92 =  -1.397% (+/-3.20%)

The code size change is (firmware with a lot of frozen code benefits the
most):

       bare-arm:  +396 +0.697%
    minimal x86: +1595 +0.979% [incl +32(data)]
       unix x64: +2408 +0.470% [incl +800(data)]
    unix nanbox: +1396 +0.309% [incl -96(data)]
          stm32: -1256 -0.318% PYBV10
         cc3200:  +288 +0.157%
        esp8266:  -260 -0.037% GENERIC
          esp32:  -216 -0.014% GENERIC[incl -1072(data)]
            nrf:  +116 +0.067% pca10040
            rp2:  -664 -0.135% PICO
           samd:  +844 +0.607% ADAFRUIT_ITSYBITSY_M4_EXPRESS

As part of this change the .mpy file format version is bumped to version 6.
And mpy-tool.py has been improved to provide a good visualisation of the
contents of .mpy files.

In summary: this commit changes the bytecode to use qstr indirection, and
reworks the .mpy file format to be simpler and allow .mpy files to be
executed in-place.  Performance is not impacted too much.  Eventually it
will be possible to store such .mpy files in a linear, read-only, memory-
mappable filesystem so they can be executed from flash/ROM.  This will
essentially be able to replace frozen code for most applications.

Signed-off-by: Damien George <damien@micropython.org>
2022-02-24 18:08:43 +11:00
Damien George ad4656b861 all: Rename BYTES_PER_WORD to MP_BYTES_PER_OBJ_WORD.
The "word" referred to by BYTES_PER_WORD is actually the size of mp_obj_t
which is not always the same as the size of a pointer on the target
architecture.  So rename this config value to better reflect what it
measures, and also prefix it with MP_.

For uses of BYTES_PER_WORD in setting the stack limit this has been
changed to sizeof(void *), because the stack usually grows with
machine-word sized values (eg an nlr_buf_t has many machine words in it).

Signed-off-by: Damien George <damien@micropython.org>
2021-02-04 22:46:42 +11:00
David CARLIER cb30928ac8 py/persistentcode: Introduce MICROPY_PERSISTENT_CODE_SAVE_FILE option.
This should be enabled when the mp_raw_code_save_file function is needed.

It is enabled for mpy-cross, and a check for defined(__APPLE__) is added to
cover Mac M1 systems.
2021-01-30 15:13:24 +11:00
Damien George 9883d8e818 py/persistentcode: Maintain root ptr list of imported native .mpy code.
On ports where normal heap memory can contain executable code (eg ARM-based
ports such as stm32), native code loaded from an .mpy file may be reclaimed
by the GC because there's no reference to the very start of the native
machine code block that is reachable from root pointers (only pointers to
internal parts of the machine code block are reachable, but that doesn't
help the GC find the memory).

This commit fixes this issue by maintaining an explicit list of root
pointers pointing to native code that is loaded from an .mpy file.  This
is not needed for all ports so is selectable by the new configuration
option MICROPY_PERSISTENT_CODE_TRACK_RELOC_CODE.  It's enabled by default
if a port does not specify any special functions to allocate or commit
executable memory.

A test is included to test that native code loaded from an .mpy file does
not get reclaimed by the GC.

Fixes #6045.

Signed-off-by: Damien George <damien@micropython.org>
2020-08-02 22:34:09 +10:00
Jim Mussared def76fe4d9 all: Use MP_ERROR_TEXT for all error messages. 2020-04-05 15:02:06 +10:00
Damien George 69661f3343 all: Reformat C and Python source code with tools/codeformat.py.
This is run with uncrustify 0.70.1, and black 19.10b0.
2020-02-28 10:33:03 +11:00
David Lechner 62537a18e3 py: Release GIL during syscalls in reader and writer code.
This releases the GIL during POSIX system calls that could block.
2020-01-26 23:26:31 +11:00
Damien George 0bd7d1f7f0 py/persistentcode: Move loading of rodata/bss to before obj/raw-code.
This makes the loading of viper-code-with-relocations a bit neater and
easier to understand, by treating the rodata/bss like a special object to
be loaded into the constant table (which is how it behaves).
2019-12-17 13:22:11 +11:00
Damien George 9ac949cdbd py/persistentcode: Make ARM Thumb archs support multiple sub-archs. 2019-12-12 20:15:28 +11:00
Damien George 360d972c16 py/nativeglue: Add new header file with native function table typedef. 2019-12-12 20:15:28 +11:00
Damien George b47e155bd0 py/persistentcode: Add ability to relocate loaded native code.
Implements text, rodata and bss generalised relocations, as well as generic
qstr-object linking.  This allows importing dynamic native modules on all
supported architectures in a unified way.
2019-12-12 20:15:28 +11:00
Damien George f4601af10a py/persistentcode: Move declarations for .mpy header from .c to .h file. 2019-11-04 16:00:05 +11:00
Damien George 23f0691fdd py/persistentcode: Make .mpy more compact with qstr directly in prelude.
Instead of encoding 4 zero bytes as placeholders for the simple_name and
source_file qstrs, and storing the qstrs after the bytecode, store the
qstrs at the location of these 4 bytes.  This saves 4 bytes per bytecode
function stored in a .mpy file (for example lcd160cr.mpy drops by 232
bytes, 4x 58 functions).  And resulting code size is slightly reduced on
ports that use this feature.
2019-10-15 16:56:27 +11:00
Damien George 9adedce42e py: Add new Xtensa-Windowed arch for native emitter.
Enabled via the configuration MICROPY_EMIT_XTENSAWIN.
2019-10-05 13:44:53 +10:00
Damien George c8c0fd4ca3 py: Rework and compress second part of bytecode prelude.
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.
2019-10-01 12:26:22 +10:00
Damien George b5ebfadbd6 py: Compress first part of bytecode prelude.
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).
2019-10-01 12:26:22 +10:00
Damien George 1f7202d122 py/bc: Replace big opcode format table with simple macro. 2019-09-26 15:27:11 +10:00
stijn 22131a6738 py/persistentcode: Enable persistent code saving for Windows ports. 2019-09-18 22:15:36 +10:00
Paul m. p. P 2920d26af5 py/persistentcode: Ensure prelude_offset is always initialised. 2019-07-01 23:46:49 +10:00
Jun Wu d165a401dc py/persistentcode: Fix compilation with load and save both enabled.
With both MICROPY_PERSISTENT_CODE_SAVE and MICROPY_PERSISTENT_CODE_LOAD
enabled the code fails to compile, due to undeclared 'n_obj'.  If
MICROPY_EMIT_NATIVE is disabled there are more errors due to the use of
undefined fields in mp_raw_code_t.

This patch fixes such compilation by avoiding undefined fields.

MICROPY_EMIT_NATIVE was changed to MICROPY_EMIT_MACHINE_CODE in this file
to match the mp_raw_code_t definition.
2019-06-28 13:59:45 +10:00
Henrik Vendelbo ab93321e31 py/persistentcode: Change "len" type to size_t for mp_obj_str_get_data. 2019-05-13 12:38:06 +10:00
Damien George 7e90e22ea5 mpy-cross: Add --version command line option to print version info.
Prints something like:

MicroPython v1.10-304-g8031b7a25 on 2019-05-02; mpy-cross emitting mpy v4
2019-05-07 13:54:20 +10:00
Damien George d9d92f27d7 py/compile: Add support to select the native emitter at runtime. 2019-03-14 12:22:25 +11:00
Damien George 9a5f92ea72 py/persistentcode: Bump .mpy version to 4. 2019-03-08 15:53:05 +11:00
Damien George 1396a026be py: Add support to save native, viper and asm code to .mpy files.
This commit adds support for saving and loading .mpy files that contain
native code (native, viper and inline-asm).  A lot of the ground work was
already done for this in the form of removing pointers from generated
native code.  The changes here are mainly to link in qstr values to the
native code, and change the format of .mpy files to contain native code
blocks (possibly mixed with bytecode).

A top-level summary:

- @micropython.native, @micropython.viper and @micropython.asm_thumb/
  asm_xtensa are now allowed in .py files when compiling to .mpy, and they
  work transparently to the user.

- Entire .py files can be compiled to native via mpy-cross -X emit=native
  and for the most part the generated .mpy files should work the same as
  their bytecode version.

- The .mpy file format is changed to 1) specify in the header if the file
  contains native code and if so the architecture (eg x86, ARMV7M, Xtensa);
  2) for each function block the kind of code is specified (bytecode,
  native, viper, asm).

- When native code is loaded from a .mpy file the native code must be
  modified (in place) to link qstr values in, just like bytecode (see
  py/persistentcode.c:arch_link_qstr() function).

In addition, this now defines a public, native ABI for dynamically loadable
native code generated by other languages, like C.
2019-03-08 15:53:05 +11:00
Damien George 636ed0ff8d py/emitglue: Remove union in mp_raw_code_t to combine bytecode & native. 2019-03-08 15:53:04 +11:00
Damien George 4f0931b21f py/persistentcode: Define static qstr set to reduce size of mpy files.
When encoded in the mpy file, if qstr <= QSTR_LAST_STATIC then store two
bytes: 0, static_qstr_id.  Otherwise encode the qstr as usual (either with
string data or a reference into the qstr window).

Reduces mpy file size by about 5%.
2019-03-05 16:32:05 +11:00
Damien George 992a6e1dea py/persistentcode: Pack qstrs directly in bytecode to reduce mpy size.
Instead of emitting two bytes in the bytecode for where the linked qstr
should be written to, it is now replaced by the actual qstr data, or a
reference into the qstr window.

Reduces mpy file size by about 10%.
2019-03-05 16:27:34 +11:00
Damien George 5996eeb48f py/persistentcode: Add a qstr window to save mpy files more efficiently.
This is an implementation of a sliding qstr window used to reduce the
number of qstrs stored in a .mpy file.  The window size is configured to 32
entries which takes a fixed 64 bytes (16-bits each) on the C stack when
loading/saving a .mpy file.  It allows to remember the most recent 32 qstrs
so they don't need to be stored again in the .mpy file.  The qstr window
uses a simple least-recently-used mechanism to discard the least recently
used qstr when the window overflows (similar to dictionary compression).
This scheme only needs a single pass to save/load the .mpy file.

Reduces mpy file size by about 25% with a window size of 32.
2019-03-05 16:25:07 +11:00
Damien George eee1e8841a py: Downcase all MP_OBJ_IS_xxx macros to make a more consistent C API.
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.
2019-02-12 14:54:51 +11:00
Sean Burton e33bc59712 py: Remove calls to file reader functions when these are disabled.
If MICROPY_PERSISTENT_CODE_LOAD or MICROPY_ENABLE_COMPILER are enabled then
code gets enabled that calls file reading functions which may be disabled
if no readers have been implemented.

To fix this, introduce a MICROPY_HAS_FILE_READER variable, which is
automatically set if MICROPY_READER_POSIX or MICROPY_READER_VFS is set but
can also be manually set if a custom reader is being implemented.  Then
disable the file reading calls if this is not set.
2019-01-27 11:08:25 +11:00
Damien George 5604b710c2 py/emitglue: When assigning bytecode only pass bytecode len if needed.
Most embedded targets will have this bit of the code disabled, saving a
small amount of code space.
2018-02-14 18:41:17 +11:00
Damien George ff93fd4f50 py/persistentcode: Bump .mpy version number to version 3.
The binary and unary ops have changed bytecode encoding.
2017-10-05 10:49:44 +11:00
Damien George a3dc1b1957 all: Remove inclusion of internal py header files.
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.
2017-10-04 12:37:50 +11:00
Anton Patrushev f008263022 py/persistentcode: Define mp_raw_code_save_file() for any unix target.
A unix target should provide POSIX open/write/close functions regardless of
its machine architecture.  Fixes issue #3325.
2017-09-25 17:09:05 +10:00
Damien George 72732fea1a py/persistentcode: Allow to compile with complex numbers disabled. 2017-06-08 00:28:28 +10:00
Damien George dd11af209d py: Add LOAD_SUPER_METHOD bytecode to allow heap-free super meth calls.
This patch allows the following code to run without allocating on the heap:

    super().foo(...)

Before this patch such a call would allocate a super object on the heap and
then load the foo method and call it right away.  The super object is only
needed to perform the lookup of the method and not needed after that.  This
patch makes an optimisation to allocate the super object on the C stack and
discard it right after use.

Changes in code size due to this patch are:

   bare-arm: +128
    minimal: +232
   unix x64: +416
unix nanbox: +364
     stmhal: +184
    esp8266: +340
     cc3200: +128
2017-04-22 23:39:20 +10:00
Damien George 1831034be1 py: Allow lexer to raise exceptions during construction.
This patch refactors the error handling in the lexer, to simplify it (ie
reduce code size).

A long time ago, when the lexer/parser/compiler were first written, the
lexer and parser were designed so they didn't use exceptions (ie nlr) to
report errors but rather returned an error code.  Over time that has
gradually changed, the parser in particular has more and more ways of
raising exceptions.  Also, the lexer never really handled all errors without
raising, eg there were some memory errors which could raise an exception
(and in these rare cases one would get a fatal nlr-not-handled fault).

This patch accepts the fact that the lexer can raise exceptions in some
cases and allows it to raise exceptions to handle all its errors, which are
for the most part just out-of-memory errors during construction of the
lexer.  This makes the lexer a bit simpler, and also the persistent code
stuff is simplified.

What this means for users of the lexer is that calls to it must be wrapped
in a nlr handler.  But all uses of the lexer already have such an nlr
handler for the parser (and compiler) so that doesn't put any extra burden
on the callers.
2017-03-14 11:52:05 +11:00
Damien George 6a11048af1 py/persistentcode: Bump .mpy version due to change in bytecode. 2017-02-17 00:19:34 +11:00
Damien George 891dc5c62c py/persistentcode: Replace mp_uint_t with size_t where appropriate. 2017-02-16 16:51:16 +11:00
Damien George 6b239c271c py: Factor out persistent-code reader into separate files.
Implementations of persistent-code reader are provided for POSIX systems
and systems using FatFS.  Macros to use these are MICROPY_READER_POSIX and
MICROPY_READER_FATFS respectively.  If an alternative implementation is
needed then a port can define the function mp_reader_new_file.
2016-11-16 18:13:50 +11:00
Damien George 6810f2c134 py: Factor persistent code load/save funcs into persistentcode.[ch]. 2016-11-16 16:14:14 +11:00