[cfe-dev] Clang as a compiler-only tool

[Roman Divacky]

Ok, I made it emit an error like this:

witten ~/llvm$ ./Release+Asserts/bin/clang -cc1 -analyze -analyzer-checker=alpha.cplusplus.VirtualCall -analyzer-store region tools/clang/test/Analysis/virtualcall.cpp
error: action RunAnalysis not compiled in


This happens to uncover a small bug though. We are emitting diagnostics in
ExecuteCompilerInvocation.cpp which then gets warn about with -verify:


witten ~/llvm$ ./Release+Asserts/bin/clang -cc1 -fsyntax-only -load /tmp/bah -plugin foobar -verify ~/hello.c
error: 'error' diagnostics seen but not expected: 
  (frontend): unable to load plugin '/tmp/bah': '/tmp/bah: cannot open shared object file: No such file or directory'

but thats a separate issue, just fwiw :)


With the patch like that (#ifndef + emitting diagnostic), is it ok?

Roman


On Sun, Nov 18, 2012 at 06:50:37PM +0000, James Molloy wrote:
> Agreed. If this is user facing, there should be a proper, explanatory
> diagnostic message. Executing llvm_unreachable is a bug, not a feature!
> 
> On 18 November 2012 17:11, Dmitri Gribenko <gribozavr at gmail.com> wrote:
> 
> > On Sun, Nov 18, 2012 at 7:06 PM, Roman Divacky <rdivacky at freebsd.org>
> > wrote:
> > > On Sun, Nov 18, 2012 at 02:45:10PM +0200, Dmitri Gribenko wrote:
> > >> On Sun, Nov 18, 2012 at 2:16 PM, Roman Divacky <rdivacky at freebsd.org>
> > wrote:
> > >> > I would like to ask about your opinion on the attached trivial patch,
> > which
> > >> > introduces #ifndef CLANG_IS_COMPILER_ONLY in two places.
> > >>
> > >> --- lib/FrontendTool/ExecuteCompilerInvocation.cpp    (revision 168286)
> > >> +++ lib/FrontendTool/ExecuteCompilerInvocation.cpp    (working copy)
> > >> @@ -79,11 +81,13 @@
> > >>      return new PrintPreprocessedAction();
> > >>    }
> > >>
> > >> +#ifndef CLANG_IS_COMPILER_ONLY
> > >>    case RewriteMacros:          return new RewriteMacrosAction();
> > >>    case RewriteObjC:            return new RewriteObjCAction();
> > >>    case RewriteTest:            return new RewriteTestAction();
> > >>    case RunAnalysis:            return new ento::AnalysisAction();
> > >>    case MigrateSource:          return new arcmt::MigrateSourceAction();
> > >> +#endif
> > >>    case RunPreprocessorOnly:    return new PreprocessOnlyAction();
> > >>    }
> > >>    llvm_unreachable("Invalid program action!");
> > >>
> > >> Won't this cause Clang to crash if the user asks for an action that is
> > >> not compiled-in?
> > >
> > > It will execute llvm_unreachable("Invalid program action!"); which is
> > fine
> > > for me. FreeBSD really needs just the compiler bits.
> > >
> > > Note that I am not advocating making this the default, just having a way
> > > to make this possible without modifying the sources.
> >
> > Well, I am just suggesting that Clang crashing on command line
> > parameter invoking an action that is disabled during compile-time is
> > not the user experience we want to provide for any Clang
> > configuration.  A proper error message would be much better.
> >
> > Dmitri
> >
> > --
> > main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
> > (j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >
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