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[3.12] gh-109627: duplicated small exit blocks need to be assigned jump target labels (#109630) (#109632)

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gh-109627: duplicated smalll exit blocks need to be assigned jump target labels (#109630)

(cherry picked from commit 9ccf0545ef)
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Irit Katriel 2023-09-22 14:27:29 +01:00 • committed by GitHub
parent 92a347997f
commit 107e14820a
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 29 additions and 6 deletions
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24
Python/flowgraph.c
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@ -562,16 +562,23 @@ check_cfg(cfg_builder *g) {
return SUCCESS;
}
static int
get_max_label(basicblock *entryblock)
{
int lbl = -1;
for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_label.id > lbl) {
lbl = b->b_label.id;
}
}
return lbl;
}
/* Calculate the actual jump target from the target_label */
static int
translate_jump_labels_to_targets(basicblock *entryblock)
{
int max_label = -1;
for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_label.id > max_label) {
max_label = b->b_label.id;
}
}
int max_label = get_max_label(entryblock);
size_t mapsize = sizeof(basicblock *) * (max_label + 1);
basicblock **label2block = (basicblock **)PyMem_Malloc(mapsize);
if (!label2block) {
@ -2035,6 +2042,7 @@ is_exit_without_lineno(basicblock *b) {
return true;
}
/* PEP 626 mandates that the f_lineno of a frame is correct
* after a frame terminates. It would be prohibitively expensive
* to continuously update the f_lineno field at runtime,
@ -2048,6 +2056,9 @@ static int
duplicate_exits_without_lineno(cfg_builder *g)
{
assert(no_empty_basic_blocks(g));
int next_lbl = get_max_label(g->g_entryblock) + 1;
/* Copy all exit blocks without line number that are targets of a jump.
*/
basicblock *entryblock = g->g_entryblock;
@ -2066,6 +2077,7 @@ duplicate_exits_without_lineno(cfg_builder *g)
target->b_predecessors--;
new_target->b_predecessors = 1;
new_target->b_next = target->b_next;
new_target->b_label.id = next_lbl++;
target->b_next = new_target;
}
}