base: Refactor logging to make log level selection cleaner

It's currently possible to change the log level in gem5 by tweaking a
set of global variables. These variables are currently exposed to
Python using SWIG. This mechanism is far from ideal for two reasons:
First, changing the log level requires that the Python world enables
or disables individual levels. Ideally, this should be a single call
where a log level is selected. Second, exporting global variables is
poorly supported by most Python frameworks. SWIG puts variables in
their own namespace and PyBind doesn't seem to support it at all.

This changeset refactors the logging code to create a more abstract
interface. Each log level is associated with an instance of a Logger
class. This class contains common functionality, an enable flag, and a
verbose flag.

Available LogLevels are described by the LogLevel class. Lower log
levels are used for more critical messages (PANIC being level 0) and
higher levels for less critical messages. The highest log level that
is printed is controlled by calling Logger:setLevel().

Change-Id: I31e44299d242d953197a8e62679250c91d6ef776
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/configs/switcheroo.py b/tests/configs/switcheroo.py
index 43a20353e..c94dc7590 100644
--- a/tests/configs/switcheroo.py
+++ b/tests/configs/switcheroo.py
@@ -105,7 +105,8 @@ def run_test(root, switcher=None, freq=1000, verbose=False):
     # Suppress "Entering event queue" messages since we get tons of them.
     # Worse yet, they include the timestamp, which makes them highly
     # variable and unsuitable for comparing as test outputs.
-    _m5.core.cvar.want_info = verbose
+    if not verbose:
+        _m5.core.Logger.setLevel(_m5.core.Logger.WARN)
 
     # instantiate configuration
     m5.instantiate()