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")

Backports commit bef16ab4e641636b4e85c3d863b4257ce0be4e6f from qemu
This commit is contained in:
Richard Henderson 2019-02-12 11:34:58 -05:00 committed by Lioncash
parent 17477ac1ca
commit f7c5f0ccbe
No known key found for this signature in database
GPG Key ID: 4E3C3CC1031BA9C7
3 changed files with 33 additions and 3 deletions

View File

@ -268,6 +268,7 @@ static inline void tcg_gen_op6ii_i64(TCGContext *s, TCGOpcode opc, TCGv_i64 a1,
static inline void gen_set_label(TCGContext *s, TCGLabel *l)
{
l->present = 1;
tcg_gen_op1(s, INDEX_op_set_label, label_arg(s, l));
}

View File

@ -254,6 +254,9 @@ TCGLabel *gen_new_label(TCGContext *s)
TCGLabel ltmp = {0};
ltmp.id = s->nb_labels++;
*l = ltmp;
#ifdef CONFIG_DEBUG_TCG
QSIMPLEQ_INSERT_TAIL(&s->labels, l, next);
#endif
return l;
}
@ -516,6 +519,9 @@ 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)
@ -3270,6 +3276,23 @@ 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
s->opt_time -= profile_getclock();
#endif

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@ -250,16 +250,21 @@ typedef struct TCGRelocation {
intptr_t addend;
} TCGRelocation;
typedef struct TCGLabel {
typedef struct TCGLabel TCGLabel;
struct TCGLabel {
unsigned present : 1;
unsigned has_value : 1;
unsigned id : 15;
unsigned id : 14;
unsigned refs : 16;
union {
uintptr_t value;
tcg_insn_unit *value_ptr;
TCGRelocation *first_reloc;
} u;
} TCGLabel;
#ifdef CONFIG_DEBUG_TCG
QSIMPLEQ_ENTRY(TCGLabel) next;
#endif
};
typedef struct TCGPool {
struct TCGPool *next;
@ -775,6 +780,7 @@ struct TCGContext {
#endif
#ifdef CONFIG_DEBUG_TCG
QSIMPLEQ_HEAD(, TCGLabel) labels;
int temps_in_use;
int goto_tb_issue_mask;
#endif