r291877 - [Sema] Restrict explicit instantation definition dllexport

[Shoaib Meenai via cfe-commits]

Requesting a merge to the 4.0 branch. This is a pretty small change, and it
fixes an assertion failure on Windows (see PR31608 for details).

On 1/12/17, 5:28 PM, "cfe-commits on behalf of Shoaib Meenai via cfe-commits" <cfe-commits-bounces at lists.llvm.org on behalf of cfe-commits at lists.llvm.org> wrote:

    Author: smeenai
    Date: Thu Jan 12 19:28:34 2017
    New Revision: 291877
    
    URL: https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject-3Frev-3D291877-26view-3Drev&d=DgIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=UFJ7c0vMtAjKBdgoPzfL-28zDS1KWJTBHGfq_xGDm1s&s=f_XKXZU8x-ZpL2CZ0EhN86GlPYk_1RLL5eWxv3GY-pw&e= 
    Log:
    [Sema] Restrict explicit instantation definition dllexport
    
    In the case where the template class itself is already `dllexport`, the
    implicit instantiation will have already emitted all members. When we
    check the explicit instantiation definition, the `Specialization` will
    have inherited the `dllexport` attribute, so we'll attempt to emit all
    members for a second time, which causes an assertion failure. Restrict
    the exporting to when the `dllexport` attribute is newly introduced by
    the explicit instantiation definition.
    
    Fixes PR31608.
    
    Differential Revision: https://urldefense.proofpoint.com/v2/url?u=https-3A__reviews.llvm.org_D28590&d=DgIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=UFJ7c0vMtAjKBdgoPzfL-28zDS1KWJTBHGfq_xGDm1s&s=_S3zURGo2pjkoiqGSalH86SQhl0uez7FVTThjoUsDBM&e= 
    
    Modified:
        cfe/trunk/lib/Sema/SemaTemplate.cpp
        cfe/trunk/test/CodeGenCXX/dllexport.cpp
    
    Modified: cfe/trunk/lib/Sema/SemaTemplate.cpp
    URL: https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_cfe_trunk_lib_Sema_SemaTemplate.cpp-3Frev-3D291877-26r1-3D291876-26r2-3D291877-26view-3Ddiff&d=DgIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=UFJ7c0vMtAjKBdgoPzfL-28zDS1KWJTBHGfq_xGDm1s&s=b0Jr4tQuZy47gIKQ8bfcMHR9cI1etlRhCEyIiB_FHUQ&e= 
    ==============================================================================
    --- cfe/trunk/lib/Sema/SemaTemplate.cpp (original)
    +++ cfe/trunk/lib/Sema/SemaTemplate.cpp Thu Jan 12 19:28:34 2017
    @@ -7789,6 +7789,7 @@ Sema::ActOnExplicitInstantiation(Scope *
       Specialization->setTemplateKeywordLoc(TemplateLoc);
       Specialization->setBraceRange(SourceRange());
     
    +  bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
       if (Attr)
         ProcessDeclAttributeList(S, Specialization, Attr);
     
    @@ -7851,8 +7852,9 @@ Sema::ActOnExplicitInstantiation(Scope *
     
         // Fix a TSK_ImplicitInstantiation followed by a
         // TSK_ExplicitInstantiationDefinition
    -    if (Old_TSK == TSK_ImplicitInstantiation &&
    -        Specialization->hasAttr<DLLExportAttr>() &&
    +    bool NewlyDLLExported =
    +        !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
    +    if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
             (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
              Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
           // In the MS ABI, an explicit instantiation definition can add a dll
    
    Modified: cfe/trunk/test/CodeGenCXX/dllexport.cpp
    URL: https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_cfe_trunk_test_CodeGenCXX_dllexport.cpp-3Frev-3D291877-26r1-3D291876-26r2-3D291877-26view-3Ddiff&d=DgIGaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=o3kDXzdBUE3ljQXKeTWOMw&m=UFJ7c0vMtAjKBdgoPzfL-28zDS1KWJTBHGfq_xGDm1s&s=flzgUkXiH3mW7lOEqDMPrQISbxAFlVVmkEaF4cimxk4&e= 
    ==============================================================================
    --- cfe/trunk/test/CodeGenCXX/dllexport.cpp (original)
    +++ cfe/trunk/test/CodeGenCXX/dllexport.cpp Thu Jan 12 19:28:34 2017
    @@ -732,13 +732,27 @@ USEMEMFUNC(ExplicitInstantiationDeclExpo
     // M32-DAG: define weak_odr dllexport x86_thiscallcc %struct.ExplicitInstantiationDeclExportedDefTemplate* @"\01??0?$ExplicitInstantiationDeclExportedDefTemplate at H@@QAE at XZ"
     // G32-DAG: define weak_odr x86_thiscallcc void @_ZN44ExplicitInstantiationDeclExportedDefTemplateIiE1fEv
     
    -template <typename T> struct ImplicitInstantiationExplicitInstantiationDefExportedTemplate { void f() {} };
    +template <typename T> struct ImplicitInstantiationExportedExplicitInstantiationDefTemplate { virtual void f() {} };
    +ImplicitInstantiationExportedExplicitInstantiationDefTemplate<int> ImplicitInstantiationExportedExplicitInstantiationDefTemplateInstance;
    +template struct __declspec(dllexport) ImplicitInstantiationExportedExplicitInstantiationDefTemplate<int>;
    +USEMEMFUNC(ImplicitInstantiationExportedExplicitInstantiationDefTemplate<int>, f);
    +// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?f@?$ImplicitInstantiationExportedExplicitInstantiationDefTemplate at H@@UAEXXZ"
    +// G32-DAG: define weak_odr x86_thiscallcc void @_ZN61ImplicitInstantiationExportedExplicitInstantiationDefTemplateIiE1fEv
    +
    +template <typename T> struct __declspec(dllexport) ImplicitInstantiationExplicitInstantiationDefExportedTemplate { virtual void f() {} };
     ImplicitInstantiationExplicitInstantiationDefExportedTemplate<int> ImplicitInstantiationExplicitInstantiationDefExportedTemplateInstance;
    -template class __declspec(dllexport) ImplicitInstantiationExplicitInstantiationDefExportedTemplate<int>;
    +template struct ImplicitInstantiationExplicitInstantiationDefExportedTemplate<int>;
     USEMEMFUNC(ImplicitInstantiationExplicitInstantiationDefExportedTemplate<int>, f);
    -// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?f@?$ImplicitInstantiationExplicitInstantiationDefExportedTemplate at H@@QAEXXZ"
    +// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?f@?$ImplicitInstantiationExplicitInstantiationDefExportedTemplate at H@@UAEXXZ"
     // G32-DAG: define weak_odr x86_thiscallcc void @_ZN61ImplicitInstantiationExplicitInstantiationDefExportedTemplateIiE1fEv
     
    +template <typename T> struct __declspec(dllexport) ImplicitInstantiationExportedExplicitInstantiationDefExportedTemplate { virtual void f() {} };
    +ImplicitInstantiationExportedExplicitInstantiationDefExportedTemplate<int> ImplicitInstantiationExportedExplicitInstantiationDefExportedTemplateInstance;
    +template struct __declspec(dllexport) ImplicitInstantiationExportedExplicitInstantiationDefExportedTemplate<int>;
    +USEMEMFUNC(ImplicitInstantiationExportedExplicitInstantiationDefExportedTemplate<int>, f);
    +// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?f@?$ImplicitInstantiationExportedExplicitInstantiationDefExportedTemplate at H@@UAEXXZ"
    +// G32-DAG: define weak_odr x86_thiscallcc void @_ZN69ImplicitInstantiationExportedExplicitInstantiationDefExportedTemplateIiE1fEv
    +
     namespace { struct InternalLinkageType {}; }
     struct __declspec(dllexport) PR23308 {
       void f(InternalLinkageType*);
    
    
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