[cfe-dev] How to get values from AttributeList
Aaron Ballman
aaron at aaronballman.com
Tue Apr 21 15:13:13 PDT 2015
On Tue, Apr 21, 2015 at 9:54 AM, LUIS MIGUEL SANCHEZ GARCIA
<luismiguel.sanchez at uc3m.es> wrote:
> 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());
There's no need to use a string to convert the APInt object, btw. ;-)
> 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"]>];
You don't want the values and the enumerators to be the same
identifiers; that seems like a dangerous idea.
> 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?
Fails in what way?
Also, that code has UB when no enumeration values are provided to your
attribute (&Values[0] would be more safely written as Values.data()).
~Aaron
>
> 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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