[RFC PATCH] logging: add a LOG_TCG_WARN for temp leaks

[Alex Bennée]

Pretty much all calls to qemu_log are either wrapped in some other
enabling check or only enabled with debug defines. Add a specific flag
for TCG warnings and expand the documentation of the qemu_log
function.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
---
 include/qemu/log-for-trace.h | 9 ++++++++-
 include/qemu/log.h           | 2 ++
 accel/tcg/translator.c       | 4 ++--
 util/log.c                   | 2 ++
 4 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/include/qemu/log-for-trace.h b/include/qemu/log-for-trace.h
index 2f0a5b080ea..521d7936243 100644
--- a/include/qemu/log-for-trace.h
+++ b/include/qemu/log-for-trace.h
@@ -29,7 +29,14 @@ static inline bool qemu_loglevel_mask(int mask)
     return (qemu_loglevel & mask) != 0;
 }
 
-/* main logging function */
+/**
+ * qemu_log: main logging function
+ *
+ * Most users shouldn't be calling qemu_log unconditionally as it adds
+ * noise to logging output. Either use qemu_log_mask() or wrap
+ * successive log calls a qemu_loglevel_mask() check and
+ * qemu_log_lock/unlock(). The tracing infrastructure does similar wrapping.
+ */
 int GCC_FMT_ATTR(1, 2) qemu_log(const char *fmt, ...);
 
 #endif
diff --git a/include/qemu/log.h b/include/qemu/log.h
index f4724f73301..e1574ef7c14 100644
--- a/include/qemu/log.h
+++ b/include/qemu/log.h
@@ -64,6 +64,8 @@ static inline bool qemu_log_separate(void)
 #define CPU_LOG_PLUGIN     (1 << 18)
 /* LOG_STRACE is used for user-mode strace logging. */
 #define LOG_STRACE         (1 << 19)
+/* Additional TCG warnings */
+#define LOG_TCG_WARN       (1 << 20)
 
 /* Lock output for a series of related logs.  Since this is not needed
  * for a single qemu_log / qemu_log_mask / qemu_log_mask_and_addr, we
diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index 603d17ff831..44396ccd7ad 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
@@ -26,8 +26,8 @@
 void translator_loop_temp_check(DisasContextBase *db)
 {
     if (tcg_check_temp_count()) {
-        qemu_log("warning: TCG temporary leaks before "
-                 TARGET_FMT_lx "\n", db->pc_next);
+        qemu_log_mask(LOG_TCG_WARN, "warning: TCG temporary leaks before "
+                      TARGET_FMT_lx "\n", db->pc_next);
     }
 }
 
diff --git a/util/log.c b/util/log.c
index bdb3d712e88..fad25d9317f 100644
--- a/util/log.c
+++ b/util/log.c
@@ -334,6 +334,8 @@ const QEMULogItem qemu_log_items[] = {
 #endif
     { LOG_STRACE, "strace",
       "log every user-mode syscall, its input, and its result" },
+    { LOG_TCG_WARN, "tcg",
+      "log TCG warnings useful to developers." },
     { 0, NULL, NULL },
 };
 
-- 
2.20.1