ABataev added inline comments.
================
Comment at: lib/AST/DeclOpenMP.cpp:164
+ if (NumClauses) {
+ Clauses = (OMPClause **)C.Allocate(sizeof(OMPClause *) * NumClauses);
+ setClauses(CL);
----------------
lildmh wrote:
> ABataev wrote:
> > lildmh wrote:
> > > ABataev wrote:
> > > > lildmh wrote:
> > > > > ABataev wrote:
> > > > > > No, bad idea. Use tail allocation for the clauses. Check the
> > > > > > implementation of `OMPRequiresDecl`
> > > > > I think it is possible to use TrailingObjects for clause storage when
> > > > > the number of clauses are known before creating the directive (e.g.,
> > > > > for OMPRequiresDecl and OMPExecutableDirective).
> > > > >
> > > > > The reason that I had to create OMPDeclareMapperDecl before parsing
> > > > > map clauses, is the mapper variable (AA in the example below) needs
> > > > > to be declared within OMPDeclareMapperDecl, because the following map
> > > > > clauses will use it.
> > > > >
> > > > > ```
> > > > > #pragma omp declare mapper(struct S AA) map(AA.field1)
> > > > > ```
> > > > >
> > > > > A possible way to get around this is to count the number of map
> > > > > clauses before hand. But this solution is not trivial since the
> > > > > normal method for parsing map clauses cannot be used (e.g., it does
> > > > > not know AA when parsing map(AA.field1)). A customized and complex
> > > > > (because it needs to handle all possible situations) parsing method
> > > > > needs to be created, just for counting clause number. I think it's
> > > > > not worthy to do this compared with allocating map clause space later.
> > > > >
> > > > > I checked the code for OMPDeclareReductionDecl that you wrote. It
> > > > > also has to be created before parsing the combiner and initializer.
> > > > > It does not have a variable number of clauses though.
> > > > >
> > > > > Any suggestions?
> > > > Instead, you can introduce special DeclContext-based declaration and
> > > > keep the reference to this declaration inside of the
> > > > `OMPDeclareMapperDecl`.
> > > Hi Alexey,
> > >
> > > Thanks a lot for your quick response! I don't think I understand your
> > > idea. Can you establish more on that?
> > >
> > > In my current implementation, OMPDeclareMapperDecl is used as the
> > > DeclConext of the variable AA in the above example, and it already
> > > includes the reference to AA's declaration.
> > >
> > > My problem is, I need to create OMPDeclareMapperDecl before parsing map
> > > clauses. But before parsing map clauses, I don't know the number of
> > > clauses. Using TrailingObject requires to know how many clauses there are
> > > when creating OMPDeclareMapperDecl. So I couldn't use TrailingObject.
> > >
> > > My current solution is to create OMPDeclareMapperDecl before parsing map
> > > clauses, and to create the clause storage after parsing finishes.
> > What I meant, that you don't need to use `OMPDeclareMapperDecl` for this,
> > instead you can add another (very simple) special declaration based on
> > `DeclContext` to use it as the parent declaration for the variable. In the
> > `OMPDeclareMapperDecl` you can keep the reference to this special
> > declaration.
> Thanks for your response! Please let me know if my understanding below is
> correct:
>
> `OMPDeclareMapperDecl` no longer inherits from `DeclContext`. Instead, we
> create something like `OMPDeclareMapperDeclContext` which inherits from
> `DeclContext`, and `OMPDeclareMapperDecl` keeps a pointer that points to this
> `OMPDeclareMapperDeclContext`. AA and map clauses are parsed within
> `OMPDeclareMapperDeclContext`.
>
> This sounds a bit more complex, but if you believe it's better, I can change
> the code. Please share your thoughts.
Yes, something like this.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D56326/new/
https://reviews.llvm.org/D56326
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
