[cfe-commits] r104941 - in /cfe/trunk: include/clang/AST/Decl.h include/clang/Basic/DiagnosticSemaKinds.td include/clang/Parse/AttributeList.h lib/AST/Decl.cpp lib/Basic/Targets.cpp lib/Frontend/PCHReaderDecl.cpp lib/Frontend/PCHWriterDecl.cpp lib/Parse/AttributeList.cpp lib/Sema/SemaDeclAttr.cpp lib/Sema/SemaLookup.cpp test/CXX/basic/basic.lookup/basic.lookup.argdep/p2.cpp

Douglas Gregor dgregor at apple.com
Fri May 28 09:40:05 PDT 2010


On May 28, 2010, at 1:20 AM, John McCall wrote:

> Author: rjmccall
> Date: Fri May 28 03:20:36 2010
> New Revision: 104941
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=104941&view=rev
> Log:
> Add a new attribute on records, __attribute__((adl_invisible)), and define
> the x86-64 __va_list_tag with this attribute.  The attribute causes the
> affected type to behave like a fundamental type when considered by ADL.
> 
> (x86-64 is the only target we currently provide with a struct-based
> __builtin_va_list)
> 
> Fixes PR6762.

This is a very heavy solution for a relatively small bug. There aren't any types other than the magical __va_list_tag that have this behavior, so introducing a user-visible attribute for it seems premature. Why not just go for the narrow fix of recognizing __va_list_tag within the ADL routines and ignoring it?

	- Doug

> 
> Modified:
>    cfe/trunk/include/clang/AST/Decl.h
>    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>    cfe/trunk/include/clang/Parse/AttributeList.h
>    cfe/trunk/lib/AST/Decl.cpp
>    cfe/trunk/lib/Basic/Targets.cpp
>    cfe/trunk/lib/Frontend/PCHReaderDecl.cpp
>    cfe/trunk/lib/Frontend/PCHWriterDecl.cpp
>    cfe/trunk/lib/Parse/AttributeList.cpp
>    cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>    cfe/trunk/lib/Sema/SemaLookup.cpp
>    cfe/trunk/test/CXX/basic/basic.lookup/basic.lookup.argdep/p2.cpp
> 
> Modified: cfe/trunk/include/clang/AST/Decl.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/Decl.h (original)
> +++ cfe/trunk/include/clang/AST/Decl.h Fri May 28 03:20:36 2010
> @@ -1999,6 +1999,11 @@
>   /// containing an object.
>   bool HasObjectMember : 1;
> 
> +  /// InvisibleToADL - This is true if this struct is invisible to
> +  /// argument-dependent lookup.  Certain builtin types have this
> +  /// property.
> +  bool InvisibleToADL : 1;
> +
> protected:
>   RecordDecl(Kind DK, TagKind TK, DeclContext *DC,
>              SourceLocation L, IdentifierInfo *Id,
> @@ -2041,6 +2046,18 @@
>   bool hasObjectMember() const { return HasObjectMember; }
>   void setHasObjectMember (bool val) { HasObjectMember = val; }
> 
> +  /// \brief Determines whether this type is invisible to C++
> +  /// argument-dependent lookup.
> +  ///
> +  /// Types with this bit set behave like fundamental types: they are
> +  /// never associated classes, and they do not add their contexts as
> +  /// associated namespaces.
> +  ///
> +  /// This can be specified in user code as __attribute__((adl_invisible)),
> +  /// but it's generally better not to.
> +  bool isInvisibleToADL() const { return InvisibleToADL; }
> +  void setInvisibleToADL(bool val = true) { InvisibleToADL = val; }
> +
>   /// \brief Determines whether this declaration represents the
>   /// injected class name.
>   ///
> 
> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri May 28 03:20:36 2010
> @@ -884,9 +884,9 @@
> def err_attribute_wrong_decl_type : Error<
>   "%0 attribute only applies to %select{function|union|"
>   "variable and function|function or method|parameter|"
> -  "parameter or Objective-C method |function, method or block|"
> +  "parameter or Objective-C method|function, method or block|"
>   "virtual method or class|function, method, or parameter|class|virtual method"
> -  "|member}1 types">;
> +  "|member|struct or union}1 types">;
> def warn_function_attribute_wrong_type : Warning<
>   "%0 only applies to function types; type here is %1">;
> def warn_gnu_inline_attribute_requires_inline : Warning<
> 
> Modified: cfe/trunk/include/clang/Parse/AttributeList.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Parse/AttributeList.h?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Parse/AttributeList.h (original)
> +++ cfe/trunk/include/clang/Parse/AttributeList.h Fri May 28 03:20:36 2010
> @@ -115,6 +115,7 @@
>     AT_weakref,
>     AT_weak_import,
>     AT_reqd_wg_size,
> +    AT_adl_invisible,
>     IgnoredAttribute,
>     UnknownAttribute
>   };
> 
> Modified: cfe/trunk/lib/AST/Decl.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Decl.cpp?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/Decl.cpp (original)
> +++ cfe/trunk/lib/AST/Decl.cpp Fri May 28 03:20:36 2010
> @@ -1596,6 +1596,7 @@
>   HasFlexibleArrayMember = false;
>   AnonymousStructOrUnion = false;
>   HasObjectMember = false;
> +  InvisibleToADL = false;
>   assert(classof(static_cast<Decl*>(this)) && "Invalid Kind!");
> }
> 
> 
> Modified: cfe/trunk/lib/Basic/Targets.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Targets.cpp?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Basic/Targets.cpp (original)
> +++ cfe/trunk/lib/Basic/Targets.cpp Fri May 28 03:20:36 2010
> @@ -1272,7 +1272,7 @@
>            "  unsigned fp_offset;"
>            "  void* overflow_arg_area;"
>            "  void* reg_save_area;"
> -           "} __va_list_tag;"
> +           "} __attribute__((adl_invisible)) __va_list_tag;"
>            "typedef __va_list_tag __builtin_va_list[1];";
>   }
> 
> 
> Modified: cfe/trunk/lib/Frontend/PCHReaderDecl.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/PCHReaderDecl.cpp?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Frontend/PCHReaderDecl.cpp (original)
> +++ cfe/trunk/lib/Frontend/PCHReaderDecl.cpp Fri May 28 03:20:36 2010
> @@ -171,6 +171,7 @@
>   RD->setHasFlexibleArrayMember(Record[Idx++]);
>   RD->setAnonymousStructOrUnion(Record[Idx++]);
>   RD->setHasObjectMember(Record[Idx++]);
> +  RD->setInvisibleToADL(Record[Idx++]);
> }
> 
> void PCHDeclReader::VisitValueDecl(ValueDecl *VD) {
> 
> Modified: cfe/trunk/lib/Frontend/PCHWriterDecl.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/PCHWriterDecl.cpp?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Frontend/PCHWriterDecl.cpp (original)
> +++ cfe/trunk/lib/Frontend/PCHWriterDecl.cpp Fri May 28 03:20:36 2010
> @@ -169,6 +169,7 @@
>   Record.push_back(D->hasFlexibleArrayMember());
>   Record.push_back(D->isAnonymousStructOrUnion());
>   Record.push_back(D->hasObjectMember());
> +  Record.push_back(D->isInvisibleToADL());
>   Code = pch::DECL_RECORD;
> }
> 
> 
> Modified: cfe/trunk/lib/Parse/AttributeList.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/AttributeList.cpp?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Parse/AttributeList.cpp (original)
> +++ cfe/trunk/lib/Parse/AttributeList.cpp Fri May 28 03:20:36 2010
> @@ -120,6 +120,7 @@
>     .Case("cf_returns_retained", AT_cf_returns_retained)
>     .Case("reqd_work_group_size", AT_reqd_wg_size)
>     .Case("no_instrument_function", AT_no_instrument_function)
> +    .Case("adl_invisible", AT_adl_invisible)
>     .Case("thiscall", AT_thiscall)
>     .Case("__cdecl", AT_cdecl)
>     .Case("__stdcall", AT_stdcall)
> 
> Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Fri May 28 03:20:36 2010
> @@ -703,7 +703,7 @@
> 
> static void HandleObjCNSObject(Decl *D, const AttributeList &Attr, Sema &S) {
>   if (Attr.getNumArgs() != 0) {
> -    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
> +    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 0;
>     return;
>   }
>   if (TypedefDecl *TD = dyn_cast<TypedefDecl>(D)) {
> @@ -720,7 +720,7 @@
> static void
> HandleOverloadableAttr(Decl *D, const AttributeList &Attr, Sema &S) {
>   if (Attr.getNumArgs() != 0) {
> -    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
> +    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 0;
>     return;
>   }
> 
> @@ -732,6 +732,21 @@
>   D->addAttr(::new (S.Context) OverloadableAttr());
> }
> 
> +static void HandleADLInvisibleAttr(Decl *d, const AttributeList &Attr, Sema &S) {
> +  if (Attr.getNumArgs() != 0) {
> +    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 0;
> +    return;
> +  }
> +
> +  if (!isa<RecordDecl>(d)) {
> +    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_decl_type)
> +      << "adl_invisible" << 12;
> +    return;
> +  }
> +
> +  cast<RecordDecl>(d)->setInvisibleToADL();
> +}
> +
> static void HandleBlocksAttr(Decl *d, const AttributeList &Attr, Sema &S) {
>   if (!Attr.getParameterName()) {
>     S.Diag(Attr.getLoc(), diag::err_attribute_argument_n_not_string)
> @@ -941,7 +956,7 @@
>                                     Sema &S) {
>   // Attribute has 3 arguments.
>   if (Attr.getNumArgs() != 3) {
> -    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 1;
> +    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 3;
>     return;
>   }
> 
> @@ -1969,6 +1984,7 @@
>     HandleObjCExceptionAttr(D, Attr, S);
>     break;
>   case AttributeList::AT_overloadable:HandleOverloadableAttr(D, Attr, S); break;
> +  case AttributeList::AT_adl_invisible: HandleADLInvisibleAttr(D, Attr, S); break;
>   case AttributeList::AT_nsobject:    HandleObjCNSObject    (D, Attr, S); break;
>   case AttributeList::AT_blocks:      HandleBlocksAttr      (D, Attr, S); break;
>   case AttributeList::AT_sentinel:    HandleSentinelAttr    (D, Attr, S); break;
> 
> Modified: cfe/trunk/lib/Sema/SemaLookup.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLookup.cpp?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaLookup.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaLookup.cpp Fri May 28 03:20:36 2010
> @@ -1500,6 +1500,10 @@
>                                   ASTContext &Context,
>                             Sema::AssociatedNamespaceSet &AssociatedNamespaces,
>                             Sema::AssociatedClassSet &AssociatedClasses) {
> +
> +  // Some classes are invisible to ADL.
> +  if (Class->isInvisibleToADL()) return;
> +
>   // C++ [basic.lookup.koenig]p2:
>   //   [...]
>   //     -- If T is a class type (including unions), its associated
> 
> Modified: cfe/trunk/test/CXX/basic/basic.lookup/basic.lookup.argdep/p2.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/basic/basic.lookup/basic.lookup.argdep/p2.cpp?rev=104941&r1=104940&r2=104941&view=diff
> ==============================================================================
> --- cfe/trunk/test/CXX/basic/basic.lookup/basic.lookup.argdep/p2.cpp (original)
> +++ cfe/trunk/test/CXX/basic/basic.lookup/basic.lookup.argdep/p2.cpp Fri May 28 03:20:36 2010
> @@ -97,3 +97,14 @@
>     foo(&bar);
>   }
> }
> +
> +// PR6762: __builtin_va_list should be invisible to ADL on all platforms.
> +void test6_function(__builtin_va_list &argv);
> +namespace test6 {
> +  void test6_function(__builtin_va_list &argv);
> +
> +  void test() {
> +    __builtin_va_list args;
> +    test6_function(args);
> +  }
> +}
> 
> 
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