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tcg: Diagnose referenced labels that have not been emitted

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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
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1
tcg/tcg-op.h
View File

@ -255,6 +255,7 @@ static inline void tcg_gen_op6ii_i64(TCGOpcode opc, TCGv_i64 a1, TCGv_i64 a2,
static inline void gen_set_label(TCGLabel *l)
{
l->present = 1;
tcg_gen_op1(INDEX_op_set_label, label_arg(l));
}

23
tcg/tcg.c
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

12
tcg/tcg.h
View File

@ -244,16 +244,21 @@ 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;
@ -685,6 +690,7 @@ struct TCGContext {
#endif
#ifdef CONFIG_DEBUG_TCG
QSIMPLEQ_HEAD(, TCGLabel) labels;
int temps_in_use;
int goto_tb_issue_mask;
#endif