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[Qemu-devel] [PATCH] tcg: Diagnose referenced labels that have not been
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH] tcg: Diagnose referenced labels that have not been emitted |
Date: |
Thu, 7 Feb 2019 19:55:51 -0800 |
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 <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
---
tcg/tcg-op.h | 1 +
tcg/tcg.h | 12 +++++++++---
tcg/tcg.c | 23 +++++++++++++++++++++++
3 files changed, 33 insertions(+), 3 deletions(-)
---
This detects errors earlier than the patch that Roman posted.
r~
diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
index 2d98868d8f..d3e51b15af 100644
--- a/tcg/tcg-op.h
+++ b/tcg/tcg-op.h
@@ -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));
}
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 045c24a357..32b7cf3489 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -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
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 20a5d8f315..9b2bf7f439 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -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
--
2.17.2
- [Qemu-devel] [PATCH] tcg: Diagnose referenced labels that have not been emitted,
Richard Henderson <=