[cfe-commits] r154776 - in /cfe/trunk/test: Analysis/objc-bool.m Headers/typedef_guards.c Lexer/utf-16.c Preprocessor/pragma_sysheader.c Sema/surpress-deprecated.c SemaCXX/warn-everthing.cpp

[Chandler Carruth]

On Mon, Apr 16, 2012 at 7:53 PM, David Blaikie <dblaikie at gmail.com> wrote:

> On Mon, Apr 16, 2012 at 10:43 AM, Chandler Carruth <chandlerc at google.com>
> wrote:
> > On Mon, Apr 16, 2012 at 7:38 PM, David Blaikie <dblaikie at gmail.com>
> wrote:
> >>
> >> On Mon, Apr 16, 2012 at 10:29 AM, Matthieu Monrocq
> >> <matthieu.monrocq at gmail.com> wrote:
> >> >
> >> >
> >> > Le 16 avril 2012 00:09, David Blaikie <dblaikie at gmail.com> a écrit :
> >> >
> >> >> Author: dblaikie
> >> >> Date: Sun Apr 15 17:09:44 2012
> >> >> New Revision: 154776
> >> >>
> >> >> URL: http://llvm.org/viewvc/llvm-project?rev=154776&view=rev
> >> >> Log:
> >> >> Fix tests that weren't actually verifying anything.
> >> >>
> >> >> Passing -verify to clang without -cc1 or -Xclang silently passes
> (with
> >> >> a
> >> >> printed warning, but lit doesn't care about that). This change adds
> >> >> -cc1
> >> >> or,
> >> >> as is necessary in one case, -Xclang to fix this so that these tests
> >> >> are
> >> >> actually verifying as intended.
> >> >>
> >> >> I'd like to change the driver so this kind of mistake could not be
> >> >> made,
> >> >> but
> >> >> I'm not entirely sure how. Further, since the driver only warns about
> >> >> unknown
> >> >> flags in general, we could have similar bugs with a misspellings of
> >> >> arguments
> >> >> that would be nice to find.
> >> >>
> >> >> Modified:
> >> >>    cfe/trunk/test/Analysis/objc-bool.m
> >> >>    cfe/trunk/test/Headers/typedef_guards.c
> >> >>    cfe/trunk/test/Lexer/utf-16.c
> >> >>    cfe/trunk/test/Preprocessor/pragma_sysheader.c
> >> >>    cfe/trunk/test/Sema/surpress-deprecated.c
> >> >>    cfe/trunk/test/SemaCXX/warn-everthing.cpp
> >> >>
> >> >> Modified: cfe/trunk/test/Analysis/objc-bool.m
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/objc-bool.m?rev=154776&r1=154775&r2=154776&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/test/Analysis/objc-bool.m (original)
> >> >> +++ cfe/trunk/test/Analysis/objc-bool.m Sun Apr 15 17:09:44 2012
> >> >> @@ -1,4 +1,4 @@
> >> >> -// RUN: %clang --analyze %s -o %t -verify
> >> >> +// RUN: %clang --analyze %s -o %t -Xclang -verify
> >> >>
> >> >>  // Test handling of ObjC bool literals.
> >> >>
> >> >>
> >> >> Modified: cfe/trunk/test/Headers/typedef_guards.c
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Headers/typedef_guards.c?rev=154776&r1=154775&r2=154776&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/test/Headers/typedef_guards.c (original)
> >> >> +++ cfe/trunk/test/Headers/typedef_guards.c Sun Apr 15 17:09:44 2012
> >> >> @@ -1,4 +1,4 @@
> >> >> -// RUN: %clang -fsyntax-only -verify %s
> >> >> +// RUN: %clang_cc1 -fsyntax-only -verify %s
> >> >>
> >> >>  // NULL is rdefined in stddef.h
> >> >>  #define NULL ((void*) 0)
> >> >>
> >> >> Modified: cfe/trunk/test/Lexer/utf-16.c
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Lexer/utf-16.c?rev=154776&r1=154775&r2=154776&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/test/Lexer/utf-16.c (original)
> >> >> +++ cfe/trunk/test/Lexer/utf-16.c Sun Apr 15 17:09:44 2012
> >> >> @@ -1,4 +1,4 @@
> >> >> -// RUN: not %clang %s -fsyntax-only -verify
> >> >> +// RUN: %clang_cc1 %s -fsyntax-only -verify
> >> >>  // rdar://7876588
> >> >>
> >> >>  // This test verifies that clang gives a decent error for UTF-16
> >> >> source
> >> >> files.
> >> >>
> >> >> Modified: cfe/trunk/test/Preprocessor/pragma_sysheader.c
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Preprocessor/pragma_sysheader.c?rev=154776&r1=154775&r2=154776&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/test/Preprocessor/pragma_sysheader.c (original)
> >> >> +++ cfe/trunk/test/Preprocessor/pragma_sysheader.c Sun Apr 15
> 17:09:44
> >> >> 2012
> >> >> @@ -1,4 +1,4 @@
> >> >> -// RUN: %clang -verify -pedantic %s -fsyntax-only
> >> >> +// RUN: %clang_cc1 -verify -pedantic %s -fsyntax-only
> >> >>  // RUN: %clang_cc1 -E %s | FileCheck %s
> >> >>  // rdar://6899937
> >> >>  #include "pragma_sysheader.h"
> >> >>
> >> >> Modified: cfe/trunk/test/Sema/surpress-deprecated.c
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/surpress-deprecated.c?rev=154776&r1=154775&r2=154776&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/test/Sema/surpress-deprecated.c (original)
> >> >> +++ cfe/trunk/test/Sema/surpress-deprecated.c Sun Apr 15 17:09:44
> 2012
> >> >> @@ -1,4 +1,4 @@
> >> >> -// RUN: %clang -fsyntax-only -Wno-deprecated-declarations -verify %s
> >> >> +// RUN: %clang_cc1 -fsyntax-only -Wno-deprecated-declarations
> -verify
> >> >> %s
> >> >>  extern void OldFunction() __attribute__((deprecated));
> >> >>
> >> >>  int main (int argc, const char * argv[]) {
> >> >>
> >> >> Modified: cfe/trunk/test/SemaCXX/warn-everthing.cpp
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-everthing.cpp?rev=154776&r1=154775&r2=154776&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/test/SemaCXX/warn-everthing.cpp (original)
> >> >> +++ cfe/trunk/test/SemaCXX/warn-everthing.cpp Sun Apr 15 17:09:44
> 2012
> >> >> @@ -1,4 +1,4 @@
> >> >> -// RUN: %clang -Weverything -fsyntax-only %s -verify
> >> >> +// RUN: %clang_cc1 -Weverything -fsyntax-only %s -verify
> >> >>
> >> >>  // This previously crashed due to a bug in the CFG.  Exercising all
> >> >>  // warnings helps check CFG construction.
> >> >> @@ -8,6 +8,6 @@
> >> >>   ~PR12271();
> >> >>  };
> >> >>
> >> >> -void testPR12271() {
> >> >> -  PR12271 a[1][1];
> >> >> -}
> >> >> \ No newline at end of file
> >> >> +void testPR12271() { // expected-warning {{no previous prototype for
> >> >> function 'testPR12271'}}
> >> >> +  PR12271 a[1][1]; // expected-warning {{unused variable 'a'}}
> >> >> +}
> >> >>
> >> >>
> >> >> _______________________________________________
> >> >> cfe-commits mailing list
> >> >> cfe-commits at cs.uiuc.edu
> >> >> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
> >> >
> >> >
> >> > The only way I would see lit actually reacting would be to terminate
> the
> >> > processus with a non-0 result, which should be reported.
> >>
> >> Right
> >>
> >> > Perhaps that we could add a "developer" option provoking this kind of
> >> > behavior for unknown flags and have lit expand %clang and %clang_cc1
> >> > automatically with this flag. This flag should then be negated in the
> >> > few
> >> > tests that actually test the driver diagnostic.
> >>
> >> Ideally, I'm wondering whether it makes sense to have even release
> >> versions of clang produce a non-zero exit code for completely unknown
> >> flags. If someone passes -foobar to clang, should we really silently
> >> (wrt exit code, at least) succeed?
> >
> >
> > What if the flag is a GCC flag that "might" work depending on what CC is
> set
> > to?
>
> Are there particular cases of this that you're aware? For what it's
> worth, GCC errors on unknown flags, which seems helpful. I could
> imagine there being certain subcategories (-f*, -g*, etc) that we
> could handle differently (either explicitly downgrading to a warning
> for them, or whatever else seemed appropriate)
>

Yes, there are loads of GCC flags that Clang doesn't support yet, even just
to drop them on the floor.

People expect Clang to be (essentially) a drop-in replacement for GCC. They
don't expect the reverse (generally), although the fact that the reverse is
not true has bitten us repeatedly already. I don't think we can justify
Clang's behavior on GCC's here.


>
> Actually, on further experimentation I don't know what GCC is doing.
> -verify, -bar, -baz produce "unrecognized option" but don't fail.
> "-foo" produces "cc1plus: error: unrecognized command line option
> "-foo"" and fails.
>

"-foo" is special -- it thinks it's an argument to cc1plus (-f... is
generally an argument to cc1plus) which has a stricter behavior.


>
> > I think we need to let users ask for either warnings or errors about
> unknown flags, just as we do today.
>
> So I understand you clearly - by this are you suggesting "no change",
> or some kind of change that would still preserve that behavior?
>

No change. Maybe I'm just not sufficiently paranoid, but this just doesn't
seem like a big enough deal to expend this much effort to fix permanently.

If you want to fix it, maybe introduce a set of warnings to lit.py? I
dunno... I'm not sure what the correct fix is, but I don't think it is to
make the user-facing Clang driver produce more errors or support more
flags. This is a problem for developers, and we should shield any solutions
to it from the user-facing interfaces.
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