[cfe-dev] AST Matcher for Decl subclass CilkSpawnDecl

[Georg Altmann]

On 20.11.2014 13:46, Manuel Klimek wrote:
> On Thu Nov 20 2014 at 1:43:48 PM Georg Altmann
> <georg.altmann at informatik.stud.uni-erlangen.de
> <mailto:georg.altmann at informatik.stud.uni-erlangen.de>> wrote:
> 
>     On 20.11.2014 10:25, Manuel Klimek wrote:
>     > On Wed Nov 19 2014 at 3:38:44 PM Georg Altmann
>     > <georg.altmann at informatik.__stud.uni-erlangen.de
>     <mailto:georg.altmann at informatik.stud.uni-erlangen.de>
>     > <mailto:georg.altmann at __informatik.stud.uni-erlangen.__de
>     <mailto:georg.altmann at informatik.stud.uni-erlangen.de>>> wrote:
>     >
>     >     Thank you for the quick reply.
>     >
>     >     I found a partial solution to my problem. I dug down into the AST
>     >     matching code and noticed RecursiveASTVisitor did not recurse into
>     >     CapturedStmt in CilkSpawnDecl. So I did the patch
>     >
>     >
>     >     diff --git a/include/clang/AST/____RecursiveASTVisitor.h
>     >     b/include/clang/AST/____RecursiveASTVisitor.h
>     >     index 35eec69..a16e772 100755
>     >     --- a/include/clang/AST/____RecursiveASTVisitor.h
>     >     +++ b/include/clang/AST/____RecursiveASTVisitor.h
>     >     @@ -1305,6 +1305,7 @@ DEF_TRAVERSE_DECL(____CapturedDecl, {
>     >        })
>     >
>     >      DEF_TRAVERSE_DECL(____CilkSpawnDecl, {
>     >     +    TRY_TO(TraverseStmt(D->____getCapturedStmt()));
>     >        })
>     >
>     >      DEF_TRAVERSE_DECL(EmptyDecl, { })
>     >
>     >
>     >     Again, this is what I want to match:
>     >     The AST:
>     >     |-CompoundStmt
>     >     | `-CilkSpawnExpr
>     >     |   |-CilkSpawnDecl
>     >     |   | `-CapturedStmt
>     >     |   |   |-CapturedDecl
>     >     |   |   | `-ImplicitParamDecl
>     >     |   |   |-ExprWithCleanups
>     >     |   |   | `-CallExpr
>     >     --------------^ this guy
>     >
>     >
>     >     After the patch, these match now:
>     >
>     >     // 1) matches
>     >     compoundStmt(
>     >       has(cilkSpawnExpr(
>     >        has(cilkSpawnDecl(
>     >          has(capturedStmt()))))))
>     >
>     >     // 2) matches and binds
>     >     compoundStmt(
>     >       has(cilkSpawnExpr(
>     >         has(cilkSpawnDecl(
>     >           has(capturedStmt(
>     >             hasDescendant(____exprWithCleanups(
>     >               has(callExpr().bind("callExpr"____))))))))))
>     >
>     >
>     >     However this doesn't match, while it should IMHO.
>     >
>     >     // 3) does not match
>     >     compoundStmt(
>     >       has(cilkSpawnExpr(
>     >         has(cilkSpawnDecl(
>     >             has(capturedStmt(
>     >                 has(exprWithCleanups())))))))
>     >
>     >
>     > Which one in this chain is the one that doesn't match? (remove inner
>     > ones until it matches, send result).
> 
> 
>     These match:
> 
>     compoundStmt(
>       has(cilkSpawnExpr(
>         has(cilkSpawnDecl(
>           has(capturedStmt()))))))
> 
>     compoundStmt(
>       has(cilkSpawnExpr(
>         has(cilkSpawnDecl(
>           has(capturedStmt(
>             has(decl()))))))))
> 
>     compoundStmt(
>       has(cilkSpawnExpr(
>         has(cilkSpawnDecl(
>           has(capturedStmt(
>             // for some reason has() does not work here
>             hasDescendant(__exprWithCleanups(
>               has(callExpr().bind("callExpr"__)))))))))))
> 
> 
>     None of these match:
> 
>     compoundStmt(
>       has(cilkSpawnExpr(
>         has(cilkSpawnDecl(
>           has(capturedStmt(
>             has(exprWithCleanups()))))))))
> 
>     compoundStmt(
>       has(cilkSpawnExpr(
>         has(cilkSpawnDecl(
>           has(capturedStmt(
>             has(expr()))))))))
> 
>     compoundStmt(
>       has(cilkSpawnExpr(
>         has(cilkSpawnDecl(
>           has(capturedStmt(
>             has(stmt()))))))))
> 
>     compoundStmt(
>       has(cilkSpawnExpr(
>         has(cilkSpawnDecl(
>           has(capturedStmt(
>             has(decl()))))))))
> 
>     To me this looks like either
>     a) the ast-dump is incorrect and ExprWithCleanups is not a direct child
>     of CapturedStmt
>     or
>     b) there is a bug with CapturedStmt in the ast matching code /
>     RecursiveASTVisitor which makes ExprWithCleanups being found as
>     descendant but not as direct child.
> 
>     Maybe a test-case against vanilla clang would be helpful? However I
>     don't know how to reproduce the AST without the cilk extensions.
> 
> 
> The problem is that the RecursiveASTVisitor and the -ast-dump logic use
> completely different code paths... I still think this is probably a bug
> in one of the two.
> +richardsmith, who knows more about this...

Just to prevent any duplicate work: remember cilkplus is based on clang
3.4. This might already be fixed in current clang.
I might dig into this deeper later. For now the hasDescendant match is
good enough for me at this point.

Regards,
Georg


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