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 <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/tcg/tcg.h b/tcg/tcg.h
index e1afde2..3fab8d6 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -323,6 +323,10 @@
int64_t restore_count;
int64_t restore_time;
#endif
+
+#ifdef CONFIG_DEBUG_TCG
+ int temps_in_use;
+#endif
};
extern TCGContext tcg_ctx;
@@ -392,6 +396,19 @@
void tcg_temp_free_i64(TCGv_i64 arg);
char *tcg_get_arg_str_i64(TCGContext *s, char *buf, int buf_size, TCGv_i64 arg);
+#if defined(CONFIG_DEBUG_TCG)
+/* If you call tcg_clear_temp_count() at the start of a section of
+ * code which is not supposed to leak any TCG temporaries, then
+ * calling tcg_check_temp_count() at the end of the section will
+ * return 1 if the section did in fact leak a temporary.
+ */
+void tcg_clear_temp_count(void);
+int tcg_check_temp_count(void);
+#else
+#define tcg_clear_temp_count() do { } while (0)
+#define tcg_check_temp_count() 0
+#endif
+
void tcg_dump_info(FILE *f, fprintf_function cpu_fprintf);
#define TCG_CT_ALIAS 0x80
