On Wed, 11 May 2016, Sören Brinkmann wrote:
> Hi Julia,
>
> On Wed, 2016-05-11 at 11:51:43 +0200, Julia Lawall wrote:
> >
> >
> > On Tue, 10 May 2016, Sören Brinkmann wrote:
> >
> > > On Wed, 2016-05-11 at 07:59:06 +0200, Julia Lawall wrote:
> > > >
> > > >
> > > > On Tue, 10 May 2016, Sören Brinkmann wrote:
> > > >
> > > > > Hi Julia,
> > > > >
> > > > > On Wed, 2016-05-11 at 07:41:20 +0200, Julia Lawall wrote:
> > > > > >
> > > > > >
> > > > > > On Tue, 10 May 2016, Sören Brinkmann wrote:
> > > > > >
> > > > > > > Hi,
> > > > > > >
> > > > > > > I'm trying to remove 'const' qualifiers from function arguments
> > > > > > > that are
> > > > > > > passed by value.
> > > > > > >
> > > > > > > e.g. I want to convert:
> > > > > > >
> > > > > > > void foobar(const int bar, const int *baz);
> > > > > > > to
> > > > > > > void foobar(int bar, const int *baz);
> > > > > > >
> > > > > > > I came up with this semantic patch:
> > > > > > > /* Remove const from arguments passed by value */
> > > > > > > @ rule1 @
> > > > > > > identifier fi, I;
> > > > > > > type T;
> > > > > > > @@
> > > > > > > fi ( ...,
> > > > > > > - const T
> > > > > > > + T
> > > > > > > I
> > > > > > > ,...
> > > > > > > )
> > > > > > > { ... }
> > > > > > >
> > > > > > > That seems to work fine on function declarations, but does not
> > > > > > > cover
> > > > > > > function prototypes. Extending the patch to function prototypes I
> > > > > > > ran
> > > > > > > into some trouble. As complete separate patch, I evolved the
> > > > > > > above to
> > > > > > > (just replacing the function body with a ';'):
> > > > > > > /* Remove const from arguments passed by value */
> > > > > > > @ rule1 @
> > > > > > > identifier fi, I;
> > > > > > > type T;
> > > > > > > @@
> > > > > > > fi ( ...,
> > > > > > > - const T
> > > > > > > + T
> > > > > > > I
> > > > > > > ,...
> > > > > > > ) ;
> > > > > > >
> > > > > > > But that is not parsed by spatch, causing this error:
> > > > > > > init_defs_builtins: /usr/local/lib/coccinelle/standard.h
> > > > > > > minus: parse error:
> > > > > > > File "const_proto.cocci", line 9, column 1, charpos = 115
> > > > > > > around = 'I',
> > > > > > > whole content = ' I'
> > > > > > >
> > > > > > > Also, using the first version of a patch on a c-file with
> > > > > > > matching function
> > > > > > > declarations that also includes function prototypes, results in
> > > > > > > both,
> > > > > > > declarations and prototypes, while using it on a header with
> > > > > > > prototypes
> > > > > > > only doesn't result in any replacements.
> > > > > > >
> > > > > > > I attach the patches and some test files for reference.
> > > > > > > const.cocci apparently correctly removes all const keywords from
> > > > > > > the
> > > > > > > test.c file, but does not change the .h at all (which is correct,
> > > > > > > just
> > > > > > > weird that it changes the prototype in the .c).
> > > > > > >
> > > > > > > The const_proto.cocci file causes the above-mentioned error.
> > > > > > >
> > > > > > > Does anybody know what I'm missing here?
> > > > > >
> > > > > > By default, when you change a function header, Coccinell changes the
> > > > > > prototype accordingly. But to be able to do that it needs to have
> > > > > > access
> > > > > > to the prototype. So you may need to give an argument like
> > > > > > --all-includes
> > > > > > (include all the .h files mentioned in the .c file) or
> > > > > > --recursive-incudes
> > > > > > (include all the .h files recurively included by any .h file
> > > > > > mentioned in
> > > > > > the .c file). --recursive-includes at least may be slow, but
> > > > > > things will
> > > > > > be done in a consistent manner.
> > > > >
> > > > > Interesting. I tried different variations of the include switches on
> > > > > the
> > > > > real code base, but none resulted in the headers to be updated.
> > > > > Though,
> > > > > with those switches I get 'different modification result for foo.h'
> > > > > warnings.
> > > > >
> > > > > For the test files, including the header in the c file and running
> > > > > spatch with --local-includes works as expected.
> > > > >
> > > > > Guess I'll dig into the headers and check if there are any unusual
> > > > > constructs causing the problem. Any hints would be appreciated :)
> > > > >
> > > > > > I will check on why the expliciti prototype rule doesn't parse.
> > > > >
> > > > > Thanks for looking into it.
> > > >
> > > > Could you send an example of a .c and .h file where the result is not as
> > > > expected?
> > >
> > > It works now... It seems something is handled significantly different
> > > depending on how the target files are specified on the command line.
> > >
> > > Initially I ran:
> > > spatch --sp-file const.cocci --local-includes --in-place --dir .
> > > and now with your hints, I changed to
> > > spatch --sp-file const.cocci --local-includes --in-place *.c
> > >
> > > That way headers are updated as expected and the warnings are gone.
> > >
> > > I can try to condense a small test case tomorrow, if you're
> > > interested/necessary.
> >
> > --dir is the proper solution. Since it is not working, I would be
> > interested in having a test case. I guess it should be a directory with
> > multiple .c files.
> >
> > When you put multiple files on the command line, you are treating them all
> > at once, ie they are all parsed and in memory at the same time. This is
> > good if there are references between .c files that have to be taken into
> > account. But obviously it doesn't scale. On the other hand, .h files
> > should be treated at the same time as the .c files that reference them, so
> > it should work.
>
> I think I have a test case that is minimal.
> I attach the following files:
> - module_a.c -- c source
> - module_a.h -- c header providing prototypes for functions in module_a.c
> - module_b.c -- c source including module_a.h
> - const.cocci -- semantic patch using fundecl syntax
> - const_proto.cocci -- semantic patch using funproto syntax
>
> The patch with funproto syntax fails as described above and is also
> redundant when headers are included in the transformation the other
> patch is doing.
>
> When I run:
> spatch --sp-file const.cocci --local-includes --in-place *.c
> things work fine and both, module_a[ch], get updated as intended.
>
> When I run
> spatch --sp-file const.cocci --local-includes --in-place --dir .
> then only the c files are updated (in-place). But, the patch output
> includes the correct header transformation (I was expecting headers to
> be updated in-place too, just as in the first case).
> Also, removing module_b.c from the test, makes spatch update both
> module.[ch] in place.
Thanks for the example files. When you run with --dir ., the output
gives:
different modification result for ./module_a.h
It detects that the resulting files are different when processed via the
different includes, so it doesn't want to overwrite the file with one
thing or the other.
julia_______________________________________________
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