[cfe-dev] How to get values from AttributeList

Tue Apr 21 06:54:13 PDT 2015

Thanks Aaron,

It was the solution. In order to complete the information* I include my
complete example, If anyone needs it.*

In the original source code I included an attribute named (own::custom)
that receive one or more *unsigned int*.

[[own::custom(1,2,3,4)]]
statement;

In file tools/clang/lib/Sema/SemaStmtAttr.cpp, I included:

static Attr *handleOWNCustomAttr(Sema &S, Stmt *St, const AttributeList &A,
                                   SourceRange Range) {
  std::vector<unsigned int> Values;
  for (unsigned int i=0;i<A.getNumArgs ();++i){
         Expr *Arg1 = A.getArgAsExpr(i);
          if (auto *L = dyn_cast<IntegerLiteral>(Arg1)) {
                llvm::APInt V = L->getValue();
                unsigned int rint = std::atoi(V.toString(10,false).c_str());
                Values.push_back(rint);
          }
  }
  return ::new (S.Context) OWNCustomAttr(A.getRange(), S.Context,
&Values[0], Values.size(),

 A.getAttributeSpellingListIndex());
}

I hope that it could help anyone.

*Now I have another question*: I would like to get the same information
with variadic enums as parameters.

I included something like (in tools/clang/include/clang/Basic/Attr.td):

def OWNCustom : Attr {
  let Spellings = [CXX11<"own", "custom">];
  let Args = [VariadicEnumArgument<"Callable", "Consumed",
                                   ["AA", "BB", "CC"],
                                   ["AA", "BB", "CC"]>];
  let Documentation = [Undocumented];
}

and in file tools/clang/lib/Sema/SemaStmtAttr.cpp I included:

static Attr *handleOWNCustomAttr(Sema &S, Stmt *St, const AttributeList &A,
                                   SourceRange Range) {

  std::vector<OWNCustom::Consumed> Values;
  for (unsigned int i=0;i<A.getNumArgs ();++i){
         IdentifierLoc *Arg1 = A.getArgAsIdent(i);
         OWNCustom::Consumed Out;
         if (OWNCustom::ConvertStrToConsumed (Arg1->Ident->getName(), Out)){
                Values.push_back(Out);
          }
  }

  return ::new (S.Context) OWNCustomAttr(A.getRange(), S.Context,
                                           &Values[0], Values.size(),

 A.getAttributeSpellingListIndex());
}

Evething works with only one attribute (e.g. [[own::custom(AA)]]), but
fails with two or more enums (e.g. [[own::custom(AA,BB)]]).

Any help?

Thanks!

Regards,
Luis.

2015-04-17 17:45 GMT+02:00 Aaron Ballman <aaron at aaronballman.com>:

> On Fri, Apr 17, 2015 at 11:38 AM, LUIS MIGUEL SANCHEZ GARCIA
> <luismiguel.sanchez at uc3m.es> wrote:
> > Hi Aaron,
> >
> > I included two integers in attr.td file for this attribute declaration.
> I
> > included the numbers by hand in the object creation
> > (I wrote a handler in SemaDeclAttr.cpp file)
> > and works, but I obtain error when I try to get the values form the
> > attribute list.
> >
> > Do you have any hint?
>
> Without seeing your code, it's hard to give a concrete answer, but I
> suspect what you want is something like:
>
> Expr *Arg = A.getArgAsExpr(0);
> if (auto *L = dyn_cast<IntegerLiteral>(Arg)) {
>   llvm::APInt V = L->getValue();
>   // Do interesting things
> }
>
> ~Aaron
>
> >
> > Thanks!
> > Luis.
> >
> > El 17/04/2015 17:23, "Aaron Ballman" <aaron at aaronballman.com> escribió:
> >>
> >> On Fri, Apr 17, 2015 at 11:05 AM, LUIS MIGUEL SANCHEZ GARCIA
> >> <luismiguel.sanchez at uc3m.es> wrote:
> >> > I would like to parser the values of a C++ attribute in clang, but I
> >> > don't
> >> > know how to get the information from the AttributeList class.
> >> >
> >> >
> >> > For example, is it better to use?
> >> >
> >> >    IdentifierLoc *Value1 = A.getArgAsIdent(0);
> >> >    IdentifierLoc *Value2 = A.getArgAsIdent(1);
> >> >
> >> >    or
> >> >
> >> >   Expr *Value1 = A.getArgAsExpr(0);
> >> >   Expr *Value2 = A.getArgAsExpr(1);
> >> >
> >> > And later?
> >>
> >> A good place to look is SemaDeclAttr.cpp; that's where parsed
> >> attributes are converted into semantic attributes that attach to
> >> declarations. (SemaStmtAttr.cpp is where you'd go for statement
> >> attributes; type attributes are a bit more involved and live in
> >> SemaType.cpp).
> >>
> >> As for whether you would be using getArgAsIdent or getArgAsExpr, that
> >> depends entirely on the declaration of your attribute in Attr.td
> >> (specifically, what kind of arguments it takes). Attributes that take
> >> an IdentifierArgument, EnumArgument, or VariadicEnumArgument all use
> >> getArgAsIdent().
> >>
> >> HTH!
> >>
> >> ~Aaron
> >>
> >> >
> >> > Thanks!
> >> >
> >> > Best regards,
> >> > Luis.
> >> > --
> >> > --
> >> > --
> >> > --------------------------------------------------
> >> > Luis Miguel Sánchez García
> >> > Computer Architecture and Technology Area.
> >> > Office 2.2.B08
> >> > Computer Science Department. UNIVERSIDAD CARLOS III DE MADRID
> >> > Universidad Carlos III de Madrid
> >> > Avda. de la Universidad, 30
> >> > 28911 Leganés - Madrid - Spain
> >> > e-mail: lmsan at arcos.inf.uc3m.es
> >> >         luismiguel.sanchez at uc3m.es
> >> >
> >> > Phone: (+34) 91 624 5951
> >> >
> >> > Linked-In: http://es.linkedin.com/in/lmsan
> >> > Twitter: http://twitter.com/lmsanchezgarcia
> >> > --------------------------------------------------
> >> >
> >> > _______________________________________________
> >> > cfe-dev mailing list
> >> > cfe-dev at cs.uiuc.edu
> >> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >> >
>

-- 
-- 
-- 
--------------------------------------------------
Luis Miguel Sánchez García
Computer Architecture and Technology Area.
Office 2.2.B08
Computer Science Department. UNIVERSIDAD CARLOS III DE MADRID
Universidad Carlos III de Madrid
Avda. de la Universidad, 30
28911 Leganés - Madrid - Spain
e-mail: lmsan at arcos.inf.uc3m.es
        luismiguel.sanchez at uc3m.es

Phone: (+34) 91 624 5951

Linked-In: http://es.linkedin.com/in/lmsan
Twitter: http://twitter.com/lmsanchezgarcia
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