a506335524
This new logic tracks when an unconditional jump/raise occurs in the
emitted code stream (bytecode or native machine code) and suppresses all
subsequent code, until a label is assigned. This eliminates a lot of
cases of dead code, with relatively simple logic.
This commit combined with the previous one (that removed the existing
dead-code finding logic) has the following code size change:
bare-arm: -16 -0.028%
minimal x86: -60 -0.036%
unix x64: -368 -0.070%
unix nanbox: -80 -0.017%
stm32: -204 -0.052% PYBV10
cc3200: +0 +0.000%
esp8266: -232 -0.033% GENERIC
esp32: -224 -0.015% GENERIC[incl -40(data)]
mimxrt: -192 -0.054% TEENSY40
renesas-ra: -200 -0.032% RA6M2_EK
nrf: +28 +0.015% pca10040
rp2: -256 -0.050% PICO
samd: -12 -0.009% ADAFRUIT_ITSYBITSY_M4_EXPRESS
Signed-off-by: Damien George <damien@micropython.org>
114 lines
4.0 KiB
C
114 lines
4.0 KiB
C
/*
|
|
* This file is part of the MicroPython project, http://micropython.org/
|
|
*
|
|
* The MIT License (MIT)
|
|
*
|
|
* Copyright (c) 2016 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.
|
|
*/
|
|
|
|
#include <assert.h>
|
|
#include <string.h>
|
|
|
|
#include "py/obj.h"
|
|
#include "py/misc.h"
|
|
#include "py/asmbase.h"
|
|
|
|
#if MICROPY_EMIT_MACHINE_CODE
|
|
|
|
void mp_asm_base_init(mp_asm_base_t *as, size_t max_num_labels) {
|
|
as->max_num_labels = max_num_labels;
|
|
as->label_offsets = m_new(size_t, max_num_labels);
|
|
}
|
|
|
|
void mp_asm_base_deinit(mp_asm_base_t *as, bool free_code) {
|
|
if (free_code) {
|
|
MP_PLAT_FREE_EXEC(as->code_base, as->code_size);
|
|
}
|
|
m_del(size_t, as->label_offsets, as->max_num_labels);
|
|
}
|
|
|
|
void mp_asm_base_start_pass(mp_asm_base_t *as, int pass) {
|
|
if (pass < MP_ASM_PASS_EMIT) {
|
|
// Reset labels so we can detect backwards jumps (and verify unique assignment)
|
|
memset(as->label_offsets, -1, as->max_num_labels * sizeof(size_t));
|
|
} else {
|
|
// allocating executable RAM is platform specific
|
|
MP_PLAT_ALLOC_EXEC(as->code_offset, (void **)&as->code_base, &as->code_size);
|
|
assert(as->code_base != NULL);
|
|
}
|
|
as->pass = pass;
|
|
as->suppress = false;
|
|
as->code_offset = 0;
|
|
}
|
|
|
|
// all functions must go through this one to emit bytes
|
|
// if as->pass < MP_ASM_PASS_EMIT, then this function just counts the number
|
|
// of bytes needed and returns NULL, and callers should not store any data
|
|
// It also returns NULL if generated code should be suppressed at this point.
|
|
uint8_t *mp_asm_base_get_cur_to_write_bytes(void *as_in, size_t num_bytes_to_write) {
|
|
mp_asm_base_t *as = as_in;
|
|
uint8_t *c = NULL;
|
|
if (as->suppress) {
|
|
return c;
|
|
}
|
|
if (as->pass == MP_ASM_PASS_EMIT) {
|
|
assert(as->code_offset + num_bytes_to_write <= as->code_size);
|
|
c = as->code_base + as->code_offset;
|
|
}
|
|
as->code_offset += num_bytes_to_write;
|
|
return c;
|
|
}
|
|
|
|
void mp_asm_base_label_assign(mp_asm_base_t *as, size_t label) {
|
|
assert(label < as->max_num_labels);
|
|
|
|
// Assiging a label ends any dead-code region, and all following machine
|
|
// code should be emitted (until another mp_asm_base_suppress_code() call).
|
|
as->suppress = false;
|
|
|
|
if (as->pass < MP_ASM_PASS_EMIT) {
|
|
// assign label offset
|
|
assert(as->label_offsets[label] == (size_t)-1);
|
|
as->label_offsets[label] = as->code_offset;
|
|
} else {
|
|
// ensure label offset has not changed from PASS_COMPUTE to PASS_EMIT
|
|
assert(as->label_offsets[label] == as->code_offset);
|
|
}
|
|
}
|
|
|
|
// align must be a multiple of 2
|
|
void mp_asm_base_align(mp_asm_base_t *as, unsigned int align) {
|
|
as->code_offset = (as->code_offset + align - 1) & (~(align - 1));
|
|
}
|
|
|
|
// this function assumes a little endian machine
|
|
void mp_asm_base_data(mp_asm_base_t *as, unsigned int bytesize, uintptr_t val) {
|
|
uint8_t *c = mp_asm_base_get_cur_to_write_bytes(as, bytesize);
|
|
if (c != NULL) {
|
|
for (unsigned int i = 0; i < bytesize; i++) {
|
|
*c++ = val;
|
|
val >>= 8;
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif // MICROPY_EMIT_MACHINE_CODE
|