Summary:
The previous logging infrastructure had several problems:
* Debugging output was emitted to standard output which is also where
the symbolized output would go. Interleaving these two separate
bits of information makes inspecting the output difficult and could
potentially break tests.
* Enabling debugging output requires modifying the script which is
not very conveninent.
* When debugging it isn't immediately obvious where the output is
coming from.
This patch uses the Python standard library logging infrastructure
which fixes all of the above problems. Logging is controlled using
two new options.
* `--log-level` - Sets the logging level, default is
`info`.
* `--log-dest` - Set the logging destination, default
is standard error.
Some simple test cases for the feature are included.
rdar://problem/49476995
Reviewers: kubamracek, yln, samsonov, dvyukov, vitalybuka
Subscribers: #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D60343
llvm-svn: 357951
836da99af9