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Fix miscompile with dead switches

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In certain very specific situations (involving switches
with asms inside dead statement expressions) we could generate
invalid code (clobbering the buffer so much that we generated
invalid instructions).  Don't emit the decision table if the
switch itself is dead.
This commit is contained in:
Michael Matz
2016-10-18 03:31:14 +02:00
parent 7ae35bf1bb
commit d042e71e9f
2 changed files with 60 additions and 7 deletions
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16
tccgen.c
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@ -5692,13 +5692,15 @@ static void block(int *bsym, int *csym, int is_expr)
a = gjmp(a); /* add implicit break */
/* case lookup */
gsym(b);
qsort(sw.p, sw.n, sizeof(void*), case_cmp);
for (b = 1; b < sw.n; b++)
if (sw.p[b - 1]->v2 >= sw.p[b]->v1)
tcc_error("duplicate case value");
gcase(sw.p, sw.n, c, &a);
if (sw.def_sym)
gjmp_addr(sw.def_sym);
if (!nocode_wanted) {
qsort(sw.p, sw.n, sizeof(void*), case_cmp);
for (b = 1; b < sw.n; b++)
if (sw.p[b - 1]->v2 >= sw.p[b]->v1)
tcc_error("duplicate case value");
gcase(sw.p, sw.n, c, &a);
if (sw.def_sym)
gjmp_addr(sw.def_sym);
}
dynarray_reset(&sw.p, &sw.n);
cur_switch = saved;
/* break label */