tcg: Diagnose referenced labels that have not been emitted

Currently, a jump to a label that is not defined anywhere will
be emitted not be relocated.  This results in a jump to a random
jump target.  With tcg debugging, print a diagnostic to the -d op
file and abort.

This could help debug or detect errors like
c2d9644e6d ("target/arm: Fix crash on conditional instruction in an IT block")

Reported-by: Roman Kapl <code@rkapl.cz>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2019-02-07 13:26:40 +00:00
parent a044e3de29
commit bef16ab4e6
3 changed files with 33 additions and 3 deletions

View file

@ -305,6 +305,9 @@ TCGLabel *gen_new_label(void)
*l = (TCGLabel){
.id = s->nb_labels++
};
#ifdef CONFIG_DEBUG_TCG
QSIMPLEQ_INSERT_TAIL(&s->labels, l, next);
#endif
return l;
}
@ -1092,6 +1095,9 @@ void tcg_func_start(TCGContext *s)
QTAILQ_INIT(&s->ops);
QTAILQ_INIT(&s->free_ops);
#ifdef CONFIG_DEBUG_TCG
QSIMPLEQ_INIT(&s->labels);
#endif
}
static inline TCGTemp *tcg_temp_alloc(TCGContext *s)
@ -3841,6 +3847,23 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
}
#endif
#ifdef CONFIG_DEBUG_TCG
/* Ensure all labels referenced have been emitted. */
{
TCGLabel *l;
bool error = false;
QSIMPLEQ_FOREACH(l, &s->labels, next) {
if (unlikely(!l->present) && l->refs) {
qemu_log_mask(CPU_LOG_TB_OP,
"$L%d referenced but not present.\n", l->id);
error = true;
}
}
assert(!error);
}
#endif
#ifdef CONFIG_PROFILER
atomic_set(&prof->opt_time, prof->opt_time - profile_getclock());
#endif