r258524 - Merge templated static member variables, fixes http://llvm.org/pr26179.

[Richard Smith via cfe-commits]

I suspect we'll need to do a little more than this: when we rebuild the
redeclaration chain, we should probably propagate the complete type to
later redeclarations in the same scope. Otherwise, if we import a module
that has a complete type and one that has an incomplete type, the
declaration found by name lookup might be the one with the incomplete type,
possibly resulting in rejects-valid on code like this:

a.h:
extern int a[5];

b.h:
extern int a[];

x.cc:
#include "a.h"
#include "b.h"
int k = sizeof(a);

On Fri, Jan 22, 2016 at 11:03 AM, Yaron Keren via cfe-commits <
cfe-commits at lists.llvm.org> wrote:

> Author: yrnkrn
> Date: Fri Jan 22 13:03:27 2016
> New Revision: 258524
>
> URL: http://llvm.org/viewvc/llvm-project?rev=258524&view=rev
> Log:
> Merge templated static member variables, fixes http://llvm.org/pr26179.
>
> Patch by Vassil Vassilev!
> Reviewed by Richard Smith.
>
>
> Added:
>     cfe/trunk/test/Modules/Inputs/PR26179/
>     cfe/trunk/test/Modules/Inputs/PR26179/A.h
>     cfe/trunk/test/Modules/Inputs/PR26179/B.h
>     cfe/trunk/test/Modules/Inputs/PR26179/basic_string.h
>     cfe/trunk/test/Modules/Inputs/PR26179/module.modulemap
>     cfe/trunk/test/Modules/pr26179.cpp
> Modified:
>     cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
>
> Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderDecl.cpp?rev=258524&r1=258523&r2=258524&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Serialization/ASTReaderDecl.cpp (original)
> +++ cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Fri Jan 22 13:03:27 2016
> @@ -2595,8 +2595,24 @@ static bool isSameEntity(NamedDecl *X, N
>    // Variables with the same type and linkage match.
>    if (VarDecl *VarX = dyn_cast<VarDecl>(X)) {
>      VarDecl *VarY = cast<VarDecl>(Y);
> -    return (VarX->getLinkageInternal() == VarY->getLinkageInternal()) &&
> -      VarX->getASTContext().hasSameType(VarX->getType(), VarY->getType());
> +    if (VarX->getLinkageInternal() == VarY->getLinkageInternal()) {
> +      ASTContext &C = VarX->getASTContext();
> +      if (C.hasSameType(VarX->getType(), VarY->getType()))
> +        return true;
> +
> +      // We can get decls with different types on the redecl chain. Eg.
> +      // template <typename T> struct S { static T Var[]; }; // #1
> +      // template <typename T> T S<T>::Var[sizeof(T)]; // #2
> +      // Only? happens when completing an incomplete array type. In this
> case
> +      // when comparing #1 and #2 we should go through their elements
> types.
> +      const ArrayType *VarXTy = C.getAsArrayType(VarX->getType());
> +      const ArrayType *VarYTy = C.getAsArrayType(VarY->getType());
> +      if (!VarXTy || !VarYTy)
> +        return false;
> +      if (VarXTy->isIncompleteArrayType() ||
> VarYTy->isIncompleteArrayType())
> +        return C.hasSameType(VarXTy->getElementType(),
> VarYTy->getElementType());
> +    }
> +    return false;
>    }
>
>    // Namespaces with the same name and inlinedness match.
>
> Added: cfe/trunk/test/Modules/Inputs/PR26179/A.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/PR26179/A.h?rev=258524&view=auto
>
> ==============================================================================
> --- cfe/trunk/test/Modules/Inputs/PR26179/A.h (added)
> +++ cfe/trunk/test/Modules/Inputs/PR26179/A.h Fri Jan 22 13:03:27 2016
> @@ -0,0 +1,4 @@
> +#include "basic_string.h"
> +#include "B.h"
> +
> +int *p = a;
>
> Added: cfe/trunk/test/Modules/Inputs/PR26179/B.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/PR26179/B.h?rev=258524&view=auto
>
> ==============================================================================
> --- cfe/trunk/test/Modules/Inputs/PR26179/B.h (added)
> +++ cfe/trunk/test/Modules/Inputs/PR26179/B.h Fri Jan 22 13:03:27 2016
> @@ -0,0 +1,2 @@
> +#include "basic_string.h"
> +extern int a[5];
>
> Added: cfe/trunk/test/Modules/Inputs/PR26179/basic_string.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/PR26179/basic_string.h?rev=258524&view=auto
>
> ==============================================================================
> --- cfe/trunk/test/Modules/Inputs/PR26179/basic_string.h (added)
> +++ cfe/trunk/test/Modules/Inputs/PR26179/basic_string.h Fri Jan 22
> 13:03:27 2016
> @@ -0,0 +1,14 @@
> +#ifndef _GLIBCXX_STRING
> +#define _GLIBCXX_STRING 1
> +
> +template<typename T>
> +struct basic_string {
> +  static T _S_empty_rep_storage[];
> +};
> +
> +template<typename T>
> +T basic_string<T>::_S_empty_rep_storage[sizeof(T)];
> +
> +extern int a[];
> +
> +#endif
>
> Added: cfe/trunk/test/Modules/Inputs/PR26179/module.modulemap
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/PR26179/module.modulemap?rev=258524&view=auto
>
> ==============================================================================
> --- cfe/trunk/test/Modules/Inputs/PR26179/module.modulemap (added)
> +++ cfe/trunk/test/Modules/Inputs/PR26179/module.modulemap Fri Jan 22
> 13:03:27 2016
> @@ -0,0 +1,9 @@
> +module A {
> +  header "A.h"
> +  export *
> +}
> +
> +module B {
> +  header "B.h"
> +  export *
> +}
>
> Added: cfe/trunk/test/Modules/pr26179.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/pr26179.cpp?rev=258524&view=auto
>
> ==============================================================================
> --- cfe/trunk/test/Modules/pr26179.cpp (added)
> +++ cfe/trunk/test/Modules/pr26179.cpp Fri Jan 22 13:03:27 2016
> @@ -0,0 +1,7 @@
> +// RUN: rm -rf %t
> +// RUN: %clang_cc1 -I%S/Inputs/PR26179 -verify %s
> +// RUN: %clang_cc1 -fmodules
> -fmodule-map-file=%S/Inputs/PR26179/module.modulemap
> -fmodules-cache-path=%t -I%S/Inputs/PR26179 -verify %s
> +
> +#include "A.h"
> +
> +// expected-no-diagnostics
>
>
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