Summary:
This is needed for later: InferClang will no longer be started once for each
source file to be analysed. Instead, it will be called to analyse several files
at once, and will analyse them one by one. Thus, `clang_lang` and `source_file`
are moved to `cFrontend_config` as references.
The biggest change this entailed was the new logging infrastructure, which was
depending on `Config.source_file`. This diff moves the logic entirely to
`Logging`, and changes the API so that executables wishing to log into files
have to set it up using `Logging.set_log_file_identifier`. This can be called
several times during the execution, allowing to dynamically change the log file
(eg, when analysing several source files one by one!).
Reviewed By: jberdine
Differential Revision: D3944148
fbshipit-source-id: 6129090
Jules Villard
d9f83094b5