[scan-build] Fix clang++ pathname again

[sberg]

Summary

e00629f777d9d62875730f40d266727df300dbb2 "[scan-build] Fix clang++ pathname" had
removed the -MAJOR.MINOR suffix, but since presumably LLVM 7 the suffix is only
-MAJOR, so ClangCXX (i.e., the CLANG_CXX environment variable passed to
clang/tools/scan-build/libexec/ccc-analyzer) now contained a non-existing
/path/to/clang-12++ (which apparently went largely unnoticed as
clang/tools/scan-build/libexec/ccc-analyzer falls back to just 'clang++' if the
executable denoted by CLANG_CXX does not exist).

For the new clang/test/Analysis/scan-build/cxx-name.test to be effective,
%scan-build must now take care to pass the clang executable's resolved pathname
(i.e., ending in .../clang-MAJOR rather than just .../clang) to --use-analyzer.

[sberg]

ping

[NoQ]

Nice, thanks!

Since recently we started doing LIT tests for scan-build in test/Analysis/scan-build, if you find a good way to test this feature feel free to add a regression test.

[sberg]

Is there a reason why "NoQ accepted this revision." kept this at "Needs Review" rather than moving it to "This revision is now accepted and ready to land."?

Anyway, I added a test now. Hope the use of REQUIRES: shell is appropriate guarding for using sh and basename (and as such would subsume the // FIXME: Actually, "perl". REQUIRES: shell found in other test files in that directory using %scan-build, or should it better also carry that FIXME comment for a perl requirement, as scan-build is written in perl?). (I didn't find out how 'shell' gets added to available_features for these tests. I only found it in clang-tools-extra/test/lit.cfg.py and compiler-rt/test/lit.common.cfg.py, but which should not be relevant here? Also, I didn't manage to verify this doesn't break anything on Windows; while my Linux build dir (at least after once having done cmake --build . --target check-all) has a tools/clang/test/Analysis/scan-build dir that I can test with bin/llvm-lit -v tools/clang/test/Analysis/scan-build, I don't get that directory at all on Windows.)

[sylvestre.ledru]

Looks good to me

[NoQ]

In D89481#2359093, @sberg wrote:

Is there a reason why "NoQ accepted this revision." kept this at "Needs Review" rather than moving it to "This revision is now accepted and ready to land."?

Dunno! I think you should commit this.

Anyway, I added a test now. Hope the use of REQUIRES: shell is appropriate guarding for using sh and basename (and as such would subsume the // FIXME: Actually, "perl". REQUIRES: shell found in other test files in that directory using %scan-build, or should it better also carry that FIXME comment for a perl requirement, as scan-build is written in perl?).

Yes, this comment is there because scan-build itself is written in perl; scan-build tests would obviously fail without it. But we don't have an actual REQUIRES: perl and REQUIRES: shell seems to be precise enough.

clang/test/Analysis/scan-build/cxx-name.test

+REQUIRES: shell
+
+RUN: %scan-build sh -c 'echo "CLANG_CXX=/$(basename "$CLANG_CXX")/"' | FileCheck %s
+
+Check that scan-build sets the CLANG_CXX environment variable (meant to be
+consumed by ccc-analyzer) to an appropriate pathname for the clang++ executable,
+derived from the pathname of the clang executable:
+
+CHECK: CLANG_CXX=/clang++{{(\.exe)?}}/

clang/test/Analysis/scan-build/lit.local.cfg

 config.substitutions.append(('%scan-build',
                              '\'%s\' --use-analyzer=%s ' % (
                                  lit.util.which('scan-build',
                                                 os.path.join(
                                                     config.clang_src_dir,
                                                     'tools',
                                                     'scan-build',
                                                     'bin')),
-                                 config.clang)))
+                                 os.path.realpath(config.clang))))

clang/tools/scan-build/bin/scan-build

if ($Clang !~ /\+\+(\.exe)?$/) {
   # executable from the clang executable name.
 
   # Determine operating system under which this copy of Perl was built.
   my $IsWinBuild = ($^O =~/msys|cygwin|MSWin32/);
   if($IsWinBuild) {
     $ClangCXX =~ s/.exe$/++.exe/;
   }
   else {
-    $ClangCXX =~ s/\-\d+\.\d+$//;
+    $ClangCXX =~ s/\-\d+(\.\d+)?$//;
     $ClangCXX .= "++";
   }
 }
 
 # Determine the location of ccc-analyzer.
 my $AbsRealBin = Cwd::realpath($RealBin);
 my $Cmd = "$AbsRealBin/../libexec/ccc-analyzer";
 my $CmdCXX = "$AbsRealBin/../libexec/c++-analyzer";