scan-build supprot relative 'file' in cdb.

[aabbaabb]

Summary

Excluded folders in scan build is turned to absolute path before
comapre to 'file' in cdb. 'file' in cdb might be a path relative
to 'directory', so we need to turn it to absolute path before
comparison.

[phosek]

LGTM

[xazax.hun]

I know that the current situation is a mess, but there is an alternative version of scan-build-py on Github, which is also distributed on pypi. Could you check if that version is also susceptible to this problem and open a pull request for the author in case it is?

The repository is here: https://github.com/rizsotto/scan-build

This would be the best way to ensure the bug is fixed for all the users.

[aabbaabb]

This comment was removed by aabbaabb.

[aabbaabb]

Gabor or Petr,
Can any one of you help me commit this change? Not sure if I could commit myself.

In D90362#2361400, @xazax.hun wrote:

I know that the current situation is a mess, but there is an alternative version of scan-build-py on Github, which is also distributed on pypi. Could you check if that version is also susceptible to this problem and open a pull request for the author in case it is?

The repository is here: https://github.com/rizsotto/scan-build

This would be the best way to ensure the bug is fixed for all the users.

Do you mean pull this change into that repo after this got submitted in trunk? Will do!

[aabbaabb]

kindly ping for help to submit this.

[phosek]

What's the plan regarding updating scan-build-py to match the upstream? It seems like this issue has already been address in the upstream version.

[xazax.hun]

In D90362#2369394, @phosek wrote:

What's the plan regarding updating scan-build-py to match the upstream? It seems like this issue has already been address in the upstream version.

As far as I understand, the author is no longer motivated to contribute to LLVM, so I think there are two ways forward:

• Just remove this from the LLVM repo and redirect users to use the GitHub/Pypi version, or
• Import the upstream fixes we need ourselves.

[aabbaabb]

I think there are also some patches that only exist here not on that repo so there is no strict upstream/downstream, just two forked versions.
Since in our use case, we would likely use this version instead of the python version (easier to update/maintain), I suggest just adding the fix we need here.
For this specific bug, the python version is already fixed in a different way by reading the code.

[haowei]

Landed in https://github.com/llvm/llvm-project/commit/d93287cac89fd50a105ac4a59c079884b8e53e49

clang/tools/scan-build-py/libscanbuild/analyze.py

for triple_path in triple_arches:
 
             # Remove all temporary files
             shutil.rmtree(extdefmap_dir, ignore_errors=True)
 
 
 def run_analyzer_parallel(args):
     """ Runs the analyzer against the given compilation database. """
 
-    def exclude(filename):
+    def exclude(filename, directory):
         """ Return true when any excluded directory prefix the filename. """
-        return any(re.match(r'^' + directory, filename)
-                   for directory in args.excludes)
+        if not os.path.isabs(filename):
+            # filename is either absolute or relative to directory. Need to turn
+            # it to absolute since 'args.excludes' are absolute paths.
+            filename = os.path.normpath(os.path.join(directory, filename))
+        return any(re.match(r'^' + exclude_directory, filename)
+                   for exclude_directory in args.excludes)
 
     consts = {
         'clang': args.clang,
         'output_dir': args.output,
         'output_format': args.output_format,
         'output_failures': args.output_failures,
         'direct_args': analyzer_params(args),
         'force_debug': args.force_debug,
         'ctu': get_ctu_config_from_args(args)
     }
 
     logging.debug('run analyzer against compilation database')
     with open(args.cdb, 'r') as handle:
         generator = (dict(cmd, **consts)
-                     for cmd in json.load(handle) if not exclude(cmd['file']))
+                     for cmd in json.load(handle) if not exclude(
+                            cmd['file'], cmd['directory']))
         # when verbose output requested execute sequentially
         pool = multiprocessing.Pool(1 if args.verbose > 2 else None)
         for current in pool.imap_unordered(run, generator):
             if current is not None:
                 # display error message from the static analyzer
                 for line in current['error_output']:
                     logging.info(line.rstrip())
         pool.close()