[cfe-commits] r173643 - Add a -pedantic warning: an anonymous union within an anonymous union is not
Richard Smith
richard at metafoo.co.uk
Mon Jan 28 15:13:58 PST 2013
On Mon, Jan 28, 2013 at 12:20 AM, Alexey Samsonov <samsonov at google.com> wrote:
>
> On Mon, Jan 28, 2013 at 7:40 AM, Richard Smith <richard at metafoo.co.uk>
> wrote:
>>
>> On Sun, Jan 27, 2013 at 7:23 PM, NAKAMURA Takumi <geek4civic at gmail.com>
>> wrote:
>>>
>>> Richard, it brought many warnings on the tree.
>>> http://bb.pgr.jp/builders/clang-3stage-x86_64-linux/builds/846
>>>
>>> What could we do? Fix extensions, or ... ?
>>
>>
>> Maybe we should just turn the warning off for LLVM and Clang;
>
>
> FTR this change breaks self-hosted LLVM/Clang build with -Werror, which is a
> bit frustrating. Can we temporary disable this warning by default or fix its
> reports across LLVM/Clang code?
It turns out that EDG's strict mode will reject the code which this
warning finds, so I'm slightly favoring (eventually) fixing the
reports, but in the short term we should just turn the warning off.
>> this is a widely-available language extension which apparently no-one even
>> noticed that we were using by accident. That said, the very first case where
>> it fires looks like a pretty egregious violation of the rules.
>>
>>>
>>> ...Takumi
>>>
>>> 2013/1/28 Richard Smith <richard-llvm at metafoo.co.uk>:
>>> > Author: rsmith
>>> > Date: Sun Jan 27 18:54:05 2013
>>> > New Revision: 173643
>>> >
>>> > URL: http://llvm.org/viewvc/llvm-project?rev=173643&view=rev
>>> > Log:
>>> > Add a -pedantic warning: an anonymous union within an anonymous union
>>> > is not
>>> > permitted in standard C++, despite being silently accepted by many
>>> > (all?) major
>>> > C++ implementations.
>>> >
>>> > Modified:
>>> > cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>> > cfe/trunk/lib/Sema/SemaDecl.cpp
>>> > cfe/trunk/test/SemaCXX/anonymous-union.cpp
>>> > cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
>>> >
>>> > Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>> > URL:
>>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=173643&r1=173642&r2=173643&view=diff
>>> >
>>> > ==============================================================================
>>> > --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>>> > +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Sun Jan 27
>>> > 18:54:05 2013
>>> > @@ -5344,6 +5344,9 @@ def err_anonymous_record_with_type : Err
>>> > def ext_anonymous_record_with_type : Extension<
>>> > "types declared in an anonymous %select{struct|union}0 are a
>>> > Microsoft "
>>> > "extension">, InGroup<Microsoft>;
>>> > +def ext_anonymous_record_with_anonymous_type : Extension<
>>> > + "nested anonymous types are an extension">,
>>> > + InGroup<DiagGroup<"nested-anon-types">>;
>>> > def err_anonymous_record_with_function : Error<
>>> > "functions cannot be declared in an anonymous
>>> > %select{struct|union}0">;
>>> > def err_anonymous_record_with_static : Error<
>>> >
>>> > Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
>>> > URL:
>>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=173643&r1=173642&r2=173643&view=diff
>>> >
>>> > ==============================================================================
>>> > --- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
>>> > +++ cfe/trunk/lib/Sema/SemaDecl.cpp Sun Jan 27 18:54:05 2013
>>> > @@ -3198,6 +3198,12 @@ Decl *Sema::BuildAnonymousStructOrUnion(
>>> > << (int)Record->isUnion();
>>> > Invalid = true;
>>> > }
>>> > + } else {
>>> > + // This is an anonymous type definition within another
>>> > anonymous type.
>>> > + // This is a popular extension, provided by Plan9, MSVC and
>>> > GCC, but
>>> > + // not part of standard C++.
>>> > + Diag(MemRecord->getLocation(),
>>> > + diag::ext_anonymous_record_with_anonymous_type);
>>> > }
>>> > } else if (isa<AccessSpecDecl>(*Mem)) {
>>> > // Any access specifier is fine.
>>> >
>>> > Modified: cfe/trunk/test/SemaCXX/anonymous-union.cpp
>>> > URL:
>>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/anonymous-union.cpp?rev=173643&r1=173642&r2=173643&view=diff
>>> >
>>> > ==============================================================================
>>> > --- cfe/trunk/test/SemaCXX/anonymous-union.cpp (original)
>>> > +++ cfe/trunk/test/SemaCXX/anonymous-union.cpp Sun Jan 27 18:54:05 2013
>>> > @@ -9,7 +9,7 @@ struct X {
>>> > int i;
>>> > float f;
>>> >
>>> > - union {
>>> > + union { // expected-warning{{nested anonymous types are an
>>> > extension}}
>>> > float f2;
>>> > mutable double d;
>>> > };
>>> > @@ -101,7 +101,7 @@ void g() {
>>> > struct BadMembers {
>>> > union {
>>> > struct X { }; // expected-error {{types cannot be declared in an
>>> > anonymous union}}
>>> > - struct { int x; int y; } y;
>>> > + struct { int x; int y; } y; // expected-warning{{nested anonymous
>>> > types are an extension}}
>>> >
>>> > void f(); // expected-error{{functions cannot be declared in an
>>> > anonymous union}}
>>> > private: int x1; // expected-error{{anonymous union cannot contain a
>>> > private data member}}
>>> > @@ -128,7 +128,7 @@ namespace test4 {
>>> > struct { // expected-warning{{anonymous structs are a GNU
>>> > extension}}
>>> > int s0; // expected-note {{declared private here}}
>>> > double s1; // expected-note {{declared private here}}
>>> > - union {
>>> > + union { // expected-warning{{nested anonymous type}}
>>> > int su0; // expected-note {{declared private here}}
>>> > double su1; // expected-note {{declared private here}}
>>> > };
>>> > @@ -136,7 +136,7 @@ namespace test4 {
>>> > union {
>>> > int u0; // expected-note {{declared private here}}
>>> > double u1; // expected-note {{declared private here}}
>>> > - struct { // expected-warning{{anonymous structs are a GNU
>>> > extension}}
>>> > + struct { // expected-warning{{anonymous structs are a GNU
>>> > extension}} expected-warning{{nested anonymous type}}
>>> > int us0; // expected-note {{declared private here}}
>>> > double us1; // expected-note {{declared private here}}
>>> > };
>>> > @@ -187,7 +187,7 @@ namespace PR8326 {
>>> >
>>> > private:
>>> > const union { // expected-warning{{anonymous union cannot be
>>> > 'const'}}
>>> > - struct { // expected-warning{{anonymous structs are a GNU
>>> > extension}}
>>> > + struct { // expected-warning{{anonymous structs are a GNU
>>> > extension}} expected-warning{{nested anonymous type}}
>>> > T x;
>>> > T y;
>>> > };
>>> >
>>> > Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
>>> > URL:
>>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp?rev=173643&r1=173642&r2=173643&view=diff
>>> >
>>> > ==============================================================================
>>> > --- cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp (original)
>>> > +++ cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Sun Jan 27
>>> > 18:54:05 2013
>>> > @@ -1153,8 +1153,8 @@ namespace ConvertedConstantExpr {
>>> > namespace IndirectField {
>>> > struct S {
>>> > struct { // expected-warning {{GNU extension}}
>>> > - union {
>>> > - struct { // expected-warning {{GNU extension}}
>>> > + union { // expected-warning {{nested anonymous types are an
>>> > extension}}
>>> > + struct { // expected-warning {{GNU extension}}
>>> > expected-warning {{nested anonymous types are an extension}}
>>> > int a;
>>> > int b;
>>> > };
>>> >
>>> >
>>> > _______________________________________________
>>> > cfe-commits mailing list
>>> > cfe-commits at cs.uiuc.edu
>>> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>
>>
>>
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>
>
>
> --
> Alexey Samsonov, MSK
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