r211005 - Hide the concept of diagnostic levels from lex, parse and sema

[Alp Toker]

On 16/06/2014 02:30, Alp Toker wrote:
> +  /// \brief Determine whether the diagnostic is known to be ignored.
> +  ///
> +  /// This can be used to opportunistically avoid expensive checks when it's
> +  /// known for certain that the diagnostic has been suppressed at the
> +  /// specified location \p Loc.
> +  ///
> +  /// \param Loc The source location we are interested in finding out the
> +  /// diagnostic state. Can be null in order to query the latest state.
> +  bool isIgnored(unsigned DiagID, SourceLocation Loc) const {
> +    return Diags->getDiagnosticLevel(DiagID, Loc, *this) ==
> +           DiagnosticIDs::Ignored;
> +  }
> +

A fun experiment to try at home following this commit:

Modify the isIgnored() function locally to return false, and then run 
make check-clang. All tests should pass, but things are never that simple..

The ~20 failing tests highlight cases where warning flags have 
introduced undesirable changes in semantic analysis, code generation or 
otherwise influenced unrelated diagnostics. Now we have an ad-hoc way to 
detect such problems.

I'll be filing bugs and fixing a few of these. Hopefully we can 
correctly model isIgnored() as an opportunistic optimisation in time for 
3.5 and eliminate side-effects introduced by -W.

Related PRs filed so far:

   http://llvm.org/bugs/show_bug.cgi?id=20048

Alp.


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