r242973 - Downgrade error about adding 'dllimport' to used free function to warning (PR24215)

[Hans Wennborg]

Thanks! Merged in r243320.

On Mon, Jul 27, 2015 at 1:23 PM, Richard Smith <richard at metafoo.co.uk> wrote:
> Approved.
>
> On Mon, Jul 27, 2015 at 1:20 PM, Hans Wennborg <hans at chromium.org> wrote:
>>
>> Ping?
>>
>> On Thu, Jul 23, 2015 at 4:45 PM, Hans Wennborg <hans at chromium.org> wrote:
>> > This isn't fixing a regression, but would be nice to have in 3.7 I
>> > think.
>> >
>> > Richard, is this OK for merging?
>> >
>> > On Wed, Jul 22, 2015 at 4:54 PM, Hans Wennborg <hans at hanshq.net> wrote:
>> >> Author: hans
>> >> Date: Wed Jul 22 18:54:51 2015
>> >> New Revision: 242973
>> >>
>> >> URL: http://llvm.org/viewvc/llvm-project?rev=242973&view=rev
>> >> Log:
>> >> Downgrade error about adding 'dllimport' to used free function to
>> >> warning (PR24215)
>> >>
>> >> The code will still work as it can reference the function via its
>> >> thunk.
>> >>
>> >> Modified:
>> >>     cfe/trunk/lib/Sema/SemaDecl.cpp
>> >>     cfe/trunk/test/Sema/dllimport.c
>> >>
>> >> Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=242973&r1=242972&r2=242973&view=diff
>> >>
>> >> ==============================================================================
>> >> --- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
>> >> +++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Jul 22 18:54:51 2015
>> >> @@ -5368,10 +5368,9 @@ static void checkDLLAttributeRedeclarati
>> >>    bool AddsAttr = !(OldImportAttr || OldExportAttr) && HasNewAttr;
>> >>
>> >>    if (AddsAttr && !IsSpecialization && !OldDecl->isImplicit()) {
>> >> -    // If the declaration hasn't been used yet, allow with a warning
>> >> for
>> >> -    // free functions and global variables.
>> >> +    // Allow with a warning for free functions and global variables.
>> >>      bool JustWarn = false;
>> >> -    if (!OldDecl->isUsed() && !OldDecl->isCXXClassMember()) {
>> >> +    if (!OldDecl->isCXXClassMember()) {
>> >>        auto *VD = dyn_cast<VarDecl>(OldDecl);
>> >>        if (VD && !VD->getDescribedVarTemplate())
>> >>          JustWarn = true;
>> >> @@ -5380,6 +5379,13 @@ static void checkDLLAttributeRedeclarati
>> >>          JustWarn = true;
>> >>      }
>> >>
>> >> +    // We cannot change a declaration that's been used because IR has
>> >> already
>> >> +    // been emitted. Dllimported functions will still work though
>> >> (modulo
>> >> +    // address equality) as they can use the thunk.
>> >> +    if (OldDecl->isUsed())
>> >> +      if (!isa<FunctionDecl>(OldDecl) || !NewImportAttr)
>> >> +        JustWarn = false;
>> >> +
>> >>      unsigned DiagID = JustWarn ?
>> >> diag::warn_attribute_dll_redeclaration
>> >>                                 :
>> >> diag::err_attribute_dll_redeclaration;
>> >>      S.Diag(NewDecl->getLocation(), DiagID)
>> >>
>> >> Modified: cfe/trunk/test/Sema/dllimport.c
>> >> URL:
>> >> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/dllimport.c?rev=242973&r1=242972&r2=242973&view=diff
>> >>
>> >> ==============================================================================
>> >> --- cfe/trunk/test/Sema/dllimport.c (original)
>> >> +++ cfe/trunk/test/Sema/dllimport.c Wed Jul 22 18:54:51 2015
>> >> @@ -143,7 +143,7 @@ __declspec(dllimport) void redecl3(); //
>> >>
>> >>                        void redecl4(); // expected-note{{previous
>> >> declaration is here}}
>> >>  void useRedecl4() { redecl4(); }
>> >> -__declspec(dllimport) void redecl4(); // expected-error{{redeclaration
>> >> of 'redecl4' cannot add 'dllimport' attribute}}
>> >> +__declspec(dllimport) void redecl4(); //
>> >> expected-warning{{redeclaration of 'redecl4' should not add 'dllimport'
>> >> attribute}}
>> >>
>> >>  // Allow with a warning if the decl hasn't been used yet.
>> >>                        void redecl5(); // expected-note{{previous
>> >> declaration is here}}
>> >>
>> >>
>> >> _______________________________________________
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>> >> cfe-commits at cs.uiuc.edu
>> >> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>
>