I've looked at this and the best compromise solution I ended up with
(before Py3K) is sketched here:
opcode.h:
#define EXTENDED_ARG 135 /* 16 higher bits of the next opcode arg */
ceval.c:
case EXTENDED_ARG:
do {
oparg <<= 16;
op = NEXTOP();
oparg += NEXTARG();
} while (op == EXTENDED_ARG);
goto dispatch_opcode;
compile.c:
static void
com_addoparg(struct compiling *c, int op, int arg)
{
if (arg < 0) {
com_error(c, PyExc_SystemError,
"com_addoparg: argument out of range");
}
if (op == SET_LINENO) {
com_set_lineno(c, arg);
if (Py_OptimizeFlag)
return;
}
do {
int arg2 = arg & 0xffff;
arg -= arg2;
if (arg > 0)
com_addbyte(c, EXTENDED_ARG);
else
com_addbyte(c, op);
com_addint(c, arg2);
} while (arg > 0);
}
But this is only difficulty level 0.
Difficulty level 1 is the jumps and their forward refs & backpatching in
compile.c.
There's no tricky solution to this (due to the absolute jumps). The only
reasonable, long-term useful solution I can think of is to build a table
of all anchors (delimiting the basic blocks of the code), then make a final
pass over the serialized basic blocks and update the anchors (with or
without EXTENDED_ARG jumps depending on the need).
However, I won't even think about it anymore whithout BDFL & Tim's
approval and strong encouragement <wink>.
--
Vladimir MARANGOZOV | Vladimir.Marangozov@inrialpes.fr
http://sirac.inrialpes.fr/~marangoz | tel:(+33-4)76615277 fax:76615252
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4