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SF bug #1053819: Segfault in tuple_of_constants

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Peepholer could be fooled into misidentifying a tuple_of_constants.
Added code to count consecutive occurrences of LOAD_CONST.
Use the count to weed out the misidentified cases.
Added a unittest.
This commit is contained in:
Raymond Hettinger 2004-10-26 08:59:14 +00:00
parent 368c0b22f8
commit 23109ef11e
2 changed files with 26 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

17
Lib/test/test_peepholer.py
View file

@ -83,6 +83,23 @@ class TestTranforms(unittest.TestCase):
self.assert_(elem in asm) self.assert_(elem in asm)
self.assert_('BUILD_TUPLE' not in asm) self.assert_('BUILD_TUPLE' not in asm)
# Bug 1053819: Tuple of constants misidentified when presented with:
# . . . opcode_with_arg 100 unary_opcode BUILD_TUPLE 1 . . .
# The following would segfault upon compilation
def crater():
(~[
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
],)
def test_elim_extra_return(self): def test_elim_extra_return(self):
# RETURN LOAD_CONST None RETURN --> RETURN # RETURN LOAD_CONST None RETURN --> RETURN
def f(x): def f(x):

10
Python/compile.c
View file

@ -419,15 +419,16 @@ tuple_of_constants(unsigned char *codestr, int n, PyObject *consts)
newconst = PyTuple_New(n); newconst = PyTuple_New(n);
if (newconst == NULL) if (newconst == NULL)
return 0; return 0;
len_consts = PyList_GET_SIZE(consts);
for (i=0 ; i<n ; i++) { for (i=0 ; i<n ; i++) {
arg = GETARG(codestr, (i*3)); arg = GETARG(codestr, (i*3));
assert(arg < len_consts);
constant = PyList_GET_ITEM(consts, arg); constant = PyList_GET_ITEM(consts, arg);
Py_INCREF(constant); Py_INCREF(constant);
PyTuple_SET_ITEM(newconst, i, constant); PyTuple_SET_ITEM(newconst, i, constant);
} }
/* Append folded constant onto consts */ /* Append folded constant onto consts */
len_consts = PyList_GET_SIZE(consts);
if (PyList_Append(consts, newconst)) { if (PyList_Append(consts, newconst)) {
Py_DECREF(newconst); Py_DECREF(newconst);
return 0; return 0;
@ -501,6 +502,7 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
unsigned char *lineno; unsigned char *lineno;
int *addrmap = NULL; int *addrmap = NULL;
int new_line, cum_orig_line, last_line, tabsiz; int new_line, cum_orig_line, last_line, tabsiz;
int cumlc=0, lastlc=0; /* Count runs of consecutive LOAD_CONST codes */
unsigned int *blocks; unsigned int *blocks;
char *name; char *name;
@ -536,6 +538,10 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
for (i=0, nops=0 ; i<codelen ; i += CODESIZE(codestr[i])) { for (i=0, nops=0 ; i<codelen ; i += CODESIZE(codestr[i])) {
addrmap[i] = i - nops; addrmap[i] = i - nops;
opcode = codestr[i]; opcode = codestr[i];
lastlc = cumlc;
cumlc = 0;
switch (opcode) { switch (opcode) {
/* Replace UNARY_NOT JUMP_IF_FALSE POP_TOP with /* Replace UNARY_NOT JUMP_IF_FALSE POP_TOP with
@ -589,6 +595,7 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
/* Skip over LOAD_CONST trueconst JUMP_IF_FALSE xx POP_TOP */ /* Skip over LOAD_CONST trueconst JUMP_IF_FALSE xx POP_TOP */
case LOAD_CONST: case LOAD_CONST:
cumlc = lastlc + 1;
j = GETARG(codestr, i); j = GETARG(codestr, i);
if (codestr[i+3] != JUMP_IF_FALSE || if (codestr[i+3] != JUMP_IF_FALSE ||
codestr[i+6] != POP_TOP || codestr[i+6] != POP_TOP ||
@ -607,6 +614,7 @@ optimize_code(PyObject *code, PyObject* consts, PyObject *names, PyObject *linen
j = GETARG(codestr, i); j = GETARG(codestr, i);
h = i - 3 * j; h = i - 3 * j;
if (h >= 0 && if (h >= 0 &&
j == lastlc &&
codestr[h] == LOAD_CONST && codestr[h] == LOAD_CONST &&
ISBASICBLOCK(blocks, h, 3*(j+1)) && ISBASICBLOCK(blocks, h, 3*(j+1)) &&
tuple_of_constants(&codestr[h], j, consts)) { tuple_of_constants(&codestr[h], j, consts)) {