PythonExtra/py/emitglue.c
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

238 lines
8.2 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
// This code glues the code emitters to the runtime.
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "py/emitglue.h"
#include "py/runtime0.h"
#include "py/bc.h"
#include "py/objfun.h"
#include "py/profile.h"
#if MICROPY_DEBUG_VERBOSE // print debugging info
#define DEBUG_PRINT (1)
#define WRITE_CODE (1)
#define DEBUG_printf DEBUG_printf
#define DEBUG_OP_printf(...) DEBUG_printf(__VA_ARGS__)
#else // don't print debugging info
#define DEBUG_printf(...) (void)0
#define DEBUG_OP_printf(...) (void)0
#endif
#if MICROPY_DEBUG_PRINTERS
mp_uint_t mp_verbose_flag = 0;
#endif
mp_raw_code_t *mp_emit_glue_new_raw_code(void) {
mp_raw_code_t *rc = m_new0(mp_raw_code_t, 1);
rc->kind = MP_CODE_RESERVED;
#if MICROPY_PY_SYS_SETTRACE
rc->line_of_definition = 0;
#endif
return rc;
}
void mp_emit_glue_assign_bytecode(mp_raw_code_t *rc, const byte *code,
#if MICROPY_PERSISTENT_CODE_SAVE || MICROPY_DEBUG_PRINTERS
size_t len,
#endif
mp_raw_code_t **children,
#if MICROPY_PERSISTENT_CODE_SAVE
size_t n_children,
#endif
mp_uint_t scope_flags) {
rc->kind = MP_CODE_BYTECODE;
rc->scope_flags = scope_flags;
rc->fun_data = code;
#if MICROPY_PERSISTENT_CODE_SAVE || MICROPY_DEBUG_PRINTERS
rc->fun_data_len = len;
#endif
rc->children = children;
#if MICROPY_PERSISTENT_CODE_SAVE
rc->n_children = n_children;
#endif
#if MICROPY_PY_SYS_SETTRACE
mp_bytecode_prelude_t *prelude = &rc->prelude;
mp_prof_extract_prelude(code, prelude);
#endif
#ifdef DEBUG_PRINT
#if !(MICROPY_PERSISTENT_CODE_SAVE || MICROPY_DEBUG_PRINTERS)
const size_t len = 0;
#endif
DEBUG_printf("assign byte code: code=%p len=" UINT_FMT " flags=%x\n", code, len, (uint)scope_flags);
#endif
}
#if MICROPY_EMIT_MACHINE_CODE
void mp_emit_glue_assign_native(mp_raw_code_t *rc, mp_raw_code_kind_t kind, void *fun_data, mp_uint_t fun_len,
mp_raw_code_t **children,
#if MICROPY_PERSISTENT_CODE_SAVE
size_t n_children,
uint16_t prelude_offset,
uint16_t n_qstr, mp_qstr_link_entry_t *qstr_link,
#endif
mp_uint_t scope_flags, mp_uint_t n_pos_args, mp_uint_t type_sig) {
assert(kind == MP_CODE_NATIVE_PY || kind == MP_CODE_NATIVE_VIPER || kind == MP_CODE_NATIVE_ASM);
// Some architectures require flushing/invalidation of the I/D caches,
// so that the generated native code which was created in data RAM will
// be available for execution from instruction RAM.
#if MICROPY_EMIT_THUMB || MICROPY_EMIT_INLINE_THUMB
#if __ICACHE_PRESENT == 1
// Flush D-cache, so the code emitted is stored in RAM.
MP_HAL_CLEAN_DCACHE(fun_data, fun_len);
// Invalidate I-cache, so the newly-created code is reloaded from RAM.
SCB_InvalidateICache();
#endif
#elif MICROPY_EMIT_ARM
#if (defined(__linux__) && defined(__GNUC__)) || __ARM_ARCH == 7
__builtin___clear_cache(fun_data, (uint8_t *)fun_data + fun_len);
#elif defined(__arm__)
// Flush I-cache and D-cache.
asm volatile (
"0:"
"mrc p15, 0, r15, c7, c10, 3\n" // test and clean D-cache
"bne 0b\n"
"mov r0, #0\n"
"mcr p15, 0, r0, c7, c7, 0\n" // invalidate I-cache and D-cache
: : : "r0", "cc");
#endif
#endif
rc->kind = kind;
rc->scope_flags = scope_flags;
rc->fun_data = fun_data;
#if MICROPY_PERSISTENT_CODE_SAVE || MICROPY_DEBUG_PRINTERS
rc->fun_data_len = fun_len;
#endif
rc->children = children;
#if MICROPY_PERSISTENT_CODE_SAVE
rc->n_children = n_children;
rc->prelude_offset = prelude_offset;
rc->n_qstr = n_qstr;
rc->qstr_link = qstr_link;
#endif
// These two entries are only needed for MP_CODE_NATIVE_ASM.
rc->n_pos_args = n_pos_args;
rc->type_sig = type_sig;
#ifdef DEBUG_PRINT
DEBUG_printf("assign native: kind=%d fun=%p len=" UINT_FMT " n_pos_args=" UINT_FMT " flags=%x\n", kind, fun_data, fun_len, n_pos_args, (uint)scope_flags);
for (mp_uint_t i = 0; i < fun_len; i++) {
if (i > 0 && i % 16 == 0) {
DEBUG_printf("\n");
}
DEBUG_printf(" %02x", ((byte *)fun_data)[i]);
}
DEBUG_printf("\n");
#ifdef WRITE_CODE
FILE *fp_write_code = fopen("out-code", "wb");
fwrite(fun_data, fun_len, 1, fp_write_code);
fclose(fp_write_code);
#endif
#else
(void)fun_len;
#endif
}
#endif
mp_obj_t mp_make_function_from_raw_code(const mp_raw_code_t *rc, const mp_module_context_t *context, const mp_obj_t *def_args) {
DEBUG_OP_printf("make_function_from_raw_code %p\n", rc);
assert(rc != NULL);
// def_args must be MP_OBJ_NULL or a tuple
assert(def_args == NULL || def_args[0] == MP_OBJ_NULL || mp_obj_is_type(def_args[0], &mp_type_tuple));
// def_kw_args must be MP_OBJ_NULL or a dict
assert(def_args == NULL || def_args[1] == MP_OBJ_NULL || mp_obj_is_type(def_args[1], &mp_type_dict));
// make the function, depending on the raw code kind
mp_obj_t fun;
switch (rc->kind) {
#if MICROPY_EMIT_NATIVE
case MP_CODE_NATIVE_PY:
case MP_CODE_NATIVE_VIPER:
fun = mp_obj_new_fun_native(def_args, rc->fun_data, context, rc->children);
// Check for a generator function, and if so change the type of the object
if ((rc->scope_flags & MP_SCOPE_FLAG_GENERATOR) != 0) {
((mp_obj_base_t *)MP_OBJ_TO_PTR(fun))->type = &mp_type_native_gen_wrap;
}
break;
#endif
#if MICROPY_EMIT_INLINE_ASM
case MP_CODE_NATIVE_ASM:
fun = mp_obj_new_fun_asm(rc->n_pos_args, rc->fun_data, rc->type_sig);
break;
#endif
default:
// rc->kind should always be set and BYTECODE is the only remaining case
assert(rc->kind == MP_CODE_BYTECODE);
fun = mp_obj_new_fun_bc(def_args, rc->fun_data, context, rc->children);
// check for generator functions and if so change the type of the object
if ((rc->scope_flags & MP_SCOPE_FLAG_GENERATOR) != 0) {
((mp_obj_base_t *)MP_OBJ_TO_PTR(fun))->type = &mp_type_gen_wrap;
}
#if MICROPY_PY_SYS_SETTRACE
mp_obj_fun_bc_t *self_fun = (mp_obj_fun_bc_t *)MP_OBJ_TO_PTR(fun);
self_fun->rc = rc;
#endif
break;
}
return fun;
}
mp_obj_t mp_make_closure_from_raw_code(const mp_raw_code_t *rc, const mp_module_context_t *context, mp_uint_t n_closed_over, const mp_obj_t *args) {
DEBUG_OP_printf("make_closure_from_raw_code %p " UINT_FMT " %p\n", rc, n_closed_over, args);
// make function object
mp_obj_t ffun;
if (n_closed_over & 0x100) {
// default positional and keyword args given
ffun = mp_make_function_from_raw_code(rc, context, args);
} else {
// default positional and keyword args not given
ffun = mp_make_function_from_raw_code(rc, context, NULL);
}
// wrap function in closure object
return mp_obj_new_closure(ffun, n_closed_over & 0xff, args + ((n_closed_over >> 7) & 2));
}