From 27bfd83c336283d1f7a5345ee386c4cd7b80db61 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Sun, 6 Mar 2011 21:39:53 +0000 Subject: tcg: Add support for debugging leakage of temporaries Add support (if CONFIG_DEBUG_TCG is defined) for debugging leakage of temporary variables. Generally any temporaries created by a target while it is translating an instruction should be freed by the end of that instruction; otherwise carefully crafted guest code could cause TCG to run out of temporaries and assert. By calling tcg_check_temp_count() after each instruction we can check that we are not leaking temporaries in this way. Signed-off-by: Peter Maydell Signed-off-by: Aurelien Jarno --- tcg/tcg.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'tcg/tcg.c') diff --git a/tcg/tcg.c b/tcg/tcg.c index 5dd6a2c613..8748c05b5a 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -450,6 +450,10 @@ static inline int tcg_temp_new_internal(TCGType type, int temp_local) s->nb_temps++; } } + +#if defined(CONFIG_DEBUG_TCG) + s->temps_in_use++; +#endif return idx; } @@ -475,6 +479,13 @@ static inline void tcg_temp_free_internal(int idx) TCGTemp *ts; int k; +#if defined(CONFIG_DEBUG_TCG) + s->temps_in_use--; + if (s->temps_in_use < 0) { + fprintf(stderr, "More temporaries freed than allocated!\n"); + } +#endif + assert(idx >= s->nb_globals && idx < s->nb_temps); ts = &s->temps[idx]; assert(ts->temp_allocated != 0); @@ -528,6 +539,27 @@ TCGv_i64 tcg_const_local_i64(int64_t val) return t0; } +#if defined(CONFIG_DEBUG_TCG) +void tcg_clear_temp_count(void) +{ + TCGContext *s = &tcg_ctx; + s->temps_in_use = 0; +} + +int tcg_check_temp_count(void) +{ + TCGContext *s = &tcg_ctx; + if (s->temps_in_use) { + /* Clear the count so that we don't give another + * warning immediately next time around. + */ + s->temps_in_use = 0; + return 1; + } + return 0; +} +#endif + void tcg_register_helper(void *func, const char *name) { TCGContext *s = &tcg_ctx; -- cgit v1.2.3