Lerking/micropython
1
0
Fork 0
mirror of https://github.com/micropython/micropython.git synced 2026-01-04 11:10:14 +01:00
Code Issues Actions 52 Packages Projects Releases Wiki Activity

py: Rework and compress second part of bytecode prelude.

Browse Source 
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.
This commit is contained in:
Damien George
2019-09-25 15:45:47 +10:00
parent b5ebfadbd6
commit c8c0fd4ca3
14 changed files with 162 additions and 119 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
py/vm.c
View File

@@ -1441,10 +1441,13 @@ unwind_loop:
&& *code_state->ip != MP_BC_RAISE_LAST) {
const byte *ip = code_state->fun_bc->bytecode;
MP_BC_PRELUDE_SIG_DECODE(ip);
size_t bc = code_state->ip - ip;
size_t code_info_size = mp_decode_uint_value(ip);
ip = mp_decode_uint_skip(ip); // skip code_info_size
bc -= code_info_size;
MP_BC_PRELUDE_SIZE_DECODE(ip);
const byte *bytecode_start = ip + n_info + n_cell;
#if !MICROPY_PERSISTENT_CODE
// so bytecode is aligned
bytecode_start = MP_ALIGN(bytecode_start, sizeof(mp_uint_t));
#endif
size_t bc = code_state->ip - bytecode_start;
#if MICROPY_PERSISTENT_CODE
qstr block_name = ip[0] | (ip[1] << 8);
qstr source_file = ip[2] | (ip[3] << 8);