On Wed, 2016-07-27 at 17:17 +0200, Thomas Schwinge wrote:
> Hi!
>
> I found that for a lot of OpenACC (and potentially also OpenMP)
> clauses
> (in C/C++ front ends; didn't look at Fortran), we use wrong location
> information. The problem is that
> c_parser_oacc_all_clauses/c_parser_omp_all_clauses calls
> cp_parser_omp_clause_name to determine the pragma_omp_clause c_kind,
> and
> that function (as documented) consumes the clause token before
> returning.
> So, when we then do "c_parser_peek_token (parser)->location" or
> similar
> in some clause parsing function, that will return the location
> information of the token _after_ the clause token, which -- at least
> very
> often -- is not desirable, in particular if that location information
> is
> used then in a build_omp_clause call, which should point to the
> clause
> token itself, and not whatever follows after that.
>
> Probably that all went unnoticed for so long, because the GCC
> testsuite
> largely is running with -fno-diagnostics-show-caret, so we don't
> visually
> see the wrong location information (and nobody pays attention to the
> colum information as given, for example, as line 2, column 32 in
> "[...]/c-c++-common/goacc/routine-2.c:2:32: error: [...]".
> There seems to be a lot of inconsistency in that in all the clause
> parsing; here is just a first patch to fix the immediate problem I've
> been observing. OK for trunk already, or need to clean this all up
> in
> one go? Do we need this on release branches, as a "quality of
> implementation" fix (wrong diagnostic locations)?
[...]
I'm not a reviewer for the C/C++ FEs so I can't really review this
patch, but it might be nice in this (or in a followup) to add some test
cases for this that explicitly test the caret information for some of
these errors.
Put this at the top of a new test file:
/* { dg-options "-fdiagnostics-show-caret" } */
to override the default -fno-diagnostics-show-caret, and use this to
quote what we expect to see after each dg-error:
/* { dg-begin-multiline-output "" }
EXPECTED CARET TEXT GOES HERE, with trailing dg- stuff trimmed off
{ dg-end-multiline-output "" } */
Hope this is constructive
Dave
