r198605 - Don't use magic constants in the digraph diagnostic
Alp Toker
alp at nuanti.com
Mon Jan 6 11:00:49 PST 2014
On 06/01/2014 18:29, Richard Smith wrote:
> On Mon Jan 06 2014 at 10:06:25 AM, Alp Toker <alp at nuanti.com
> <mailto:alp at nuanti.com>> wrote:
>
>
> On 06/01/2014 17:34, Jordan Rose wrote:
> > This changes the message for templates in a way that is less
> informative.
>
> No change in output. Do you mean the string in the TableGen file
> is now
> less informative?
>
> > In other cases where we use tokens as diagnostic arguments, the
> message makes sense whether or not the token text is quoted. Here,
> that's not true: the problem isn't about the literal word
> "template" but about a particular template (like "vector"). Using
> tok::annot_template_id as if it were a real token seems wrong
>
> That was the reason I changed the "magic token kind" in use from
> tok::kw_template to tok::annot_template_id. tok::kw_template
> relates to
> "template" whereas tok::annot_template_id is a synonym for "template
> name" so this appears a better choice to use as the placeholder.
>
>
> It's a synonym for 'template id' (a template name followed by template
> arguments), not for 'template name'. Using it here is inappropriate.
Diagnostics seem to call it that way, with 'template-id' not appearing
rarely:
def err_template_id_not_a_type : Error<
"template name refers to non-type template %0">;
I agree it's not fully appropriate, but it's more appropriate than the
previous tok::kw_template given that there isn't a "template" keyword in
sight:
D<::F> A2; // expected-error{{found '<::' after a template name which
forms the digraph}}
Can you think of a better alternative to either?
Alp.
> The thought experiment here is that
> ExpectAndConsume(tok::annot_template_id) would emit the correct
> diagnostic message, which it hopefully does at this point (other than
> that it would assert right now due to the special token check).
>
> > , particularly because the comment says it's intended for use
> with function template names.
>
> That's an interesting point but I didn't quite understand. Can you
> explain a bit further?
>
> >
> > I'd rather have two variants for this diagnostic, or use an enum
> specifically marked as "keep in sync with this diagnostic"
> (slightly better than 0-1-2-3-4). Is there a reason you
> specifically wanted to change this one?
>
> Chose this diagnostic to demonstrate the new diagnostic printing
> facility introduced in the previous commit. It looked like a good
> candidate to upgrade first because of the odd use of tok::kw_template.
>
> The idea with the ongoing diagnostic effort is to make the
> messages more
> consistent, clearly written and easy to maintain so if it's
> missing the
> mark we should deal with that.
>
> Alp.
>
>
> >
> > Jordan
> >
> >
> >
> > On Jan 6, 2014, at 4:54 , Alp Toker <alp at nuanti.com
> <mailto:alp at nuanti.com>> wrote:
> >
> >> Author: alp
> >> Date: Mon Jan 6 06:54:32 2014
> >> New Revision: 198605
> >>
> >> URL: http://llvm.org/viewvc/llvm-project?rev=198605&view=rev
> >> Log:
> >> Don't use magic constants in the digraph diagnostic
> >>
> >> Modified:
> >> cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
> >> cfe/trunk/lib/Parse/ParseExprCXX.cpp
> >>
> >> Modified: cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
> >> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td?rev=198605&r1=198604&r2=198605&view=diff
> >>
> ==============================================================================
> >> --- cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td
> (original)
> >> +++ cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td Mon
> Jan 6 06:54:32 2014
> >> @@ -641,9 +641,7 @@ def err_ctor_init_missing_comma : Error<
> >> def err_friend_decl_defines_type : Error<
> >> "cannot define a type in a friend declaration">;
> >> def err_missing_whitespace_digraph : Error<
> >> - "found '<::' after a "
> >> - "%select{template
> name|const_cast|dynamic_cast|reinterpret_cast|static_cast}0"
> >> - " which forms the digraph '<:' (aka '[') and a ':', did you
> mean '< ::'?">;
> >> + "found '<::' after a %0 which forms the digraph '<:' (aka
> '[') and a ':', did you mean '< ::'?">;
> >>
> >> def ext_deleted_function : ExtWarn<
> >> "deleted function definitions are a C++11 extension">,
> InGroup<CXX11>;
> >>
> >> Modified: cfe/trunk/lib/Parse/ParseExprCXX.cpp
> >> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseExprCXX.cpp?rev=198605&r1=198604&r2=198605&view=diff
> >>
> ==============================================================================
> >> --- cfe/trunk/lib/Parse/ParseExprCXX.cpp (original)
> >> +++ cfe/trunk/lib/Parse/ParseExprCXX.cpp Mon Jan 6 06:54:32 2014
> >> @@ -24,18 +24,6 @@
> >>
> >> using namespace clang;
> >>
> >> -static int SelectDigraphErrorMessage(tok::TokenKind Kind) {
> >> - switch (Kind) {
> >> - case tok::kw_template: return 0;
> >> - case tok::kw_const_cast: return 1;
> >> - case tok::kw_dynamic_cast: return 2;
> >> - case tok::kw_reinterpret_cast: return 3;
> >> - case tok::kw_static_cast: return 4;
> >> - default:
> >> - llvm_unreachable("Unknown type for digraph error message.");
> >> - }
> >> -}
> >> -
> >> // Are the two tokens adjacent in the same source file?
> >> bool Parser::areTokensAdjacent(const Token &First, const Token
> &Second) {
> >> SourceManager &SM = PP.getSourceManager();
> >> @@ -56,8 +44,7 @@ static void FixDigraph(Parser &P, Prepro
> >> Range.setBegin(DigraphToken.getLocation());
> >> Range.setEnd(ColonToken.getLocation());
> >> P.Diag(DigraphToken.getLocation(),
> diag::err_missing_whitespace_digraph)
> >> - << SelectDigraphErrorMessage(Kind)
> >> - << FixItHint::CreateReplacement(Range, "< ::");
> >> + << Kind << FixItHint::CreateReplacement(Range, "< ::");
> >>
> >> // Update token information to reflect their change in token
> type.
> >> ColonToken.setKind(tok::coloncolon);
> >> @@ -93,8 +80,8 @@ void Parser::CheckForTemplateAndDigraph(
> >> Template,
> MemberOfUnknownSpecialization))
> >> return;
> >>
> >> - FixDigraph(*this, PP, Next, SecondToken, tok::kw_template,
> >> - /*AtDigraph*/false);
> >> + FixDigraph(*this, PP, Next, SecondToken, tok::annot_template_id,
> >> + /*AtDigraph*/ false);
> >> }
> >>
> >> /// \brief Emits an error for a left parentheses after a double
> colon.
> >>
> >>
> >> _______________________________________________
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