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GCC faithfully calculates visibility for variables independently of

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whether it's a declaration or not, then ignores that information for
declarations unless it was explicitly given.  It's not totally clear
how that should be mapped into a sane system, but make an effort.

llvm-svn: 117780
This commit is contained in:
John McCall
2010-10-30 09:18:49 +00:00
parent 7d11382b8c
commit 36cd5cc150
2 changed files with 35 additions and 23 deletions
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42
clang/lib/AST/Decl.cpp
View File

@@ -255,21 +255,17 @@ static LVPair getLVForNamespaceScopeDecl(const NamedDecl *D,
//
// Note that we don't want to make the variable non-external
// because of this, but unique-external linkage suits us.
if (Context.getLangOptions().CPlusPlus && !ExplicitVisibility &&
!Var->isExternC()) {
if (Context.getLangOptions().CPlusPlus && !Var->isExternC()) {
LVPair TypeLV = Var->getType()->getLinkageAndVisibility();
if (TypeLV.first != ExternalLinkage)
return LVPair(UniqueExternalLinkage, DefaultVisibility);
// Otherwise, ignore type visibility for declarations.
if (!isDeclaration)
if (!isDeclaration && !ExplicitVisibility)
LV.second = minVisibility(LV.second, TypeLV.second);
}
// Don't consider -fvisibility for pure declarations.
if (isDeclaration) {
if (isDeclaration)
ConsiderGlobalVisibility = false;
}
if (!Context.getLangOptions().CPlusPlus &&
(Var->getStorageClass() == SC_Extern ||
@@ -524,24 +520,24 @@ static LVPair getLVForClassMember(const NamedDecl *D,
// Static data members.
} else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
// If we don't have explicit visibility information in the
// hierarchy, apply the LV from its type. See the comment about
// namespace-scope variables for justification for this
// optimization.
if (!HasExplicitVisibility) {
LVPair TypeLV = VD->getType()->getLinkageAndVisibility();
if (TypeLV.first != ExternalLinkage)
LV.first = minLinkage(LV.first, UniqueExternalLinkage);
LV.second = minVisibility(LV.second, TypeLV.second);
bool IsDefinition = (VD->getDefinition() &&
VD->getTemplateSpecializationKind()
!= TSK_ExplicitInstantiationDeclaration);
// GCC just ignores the visibility of a variable declaration
// unless it's explicit.
if (!IsDefinition && !HasExplicitVisibility) {
LV.second = DefaultVisibility;
ConsiderGlobalVisibility = false;
}
// Ignore global visibility if it's an extern template or
// just a declaration.
if (ConsiderGlobalVisibility)
ConsiderGlobalVisibility =
(VD->getDefinition() &&
VD->getTemplateSpecializationKind()
!= TSK_ExplicitInstantiationDeclaration);
// Modify the variable's linkage by its type, but ignore the
// type's visibility unless it's a definition.
LVPair TypeLV = VD->getType()->getLinkageAndVisibility();
if (TypeLV.first != ExternalLinkage)
LV.first = minLinkage(LV.first, UniqueExternalLinkage);
if (IsDefinition && !HasExplicitVisibility)
LV.second = minVisibility(LV.second, TypeLV.second);
}
// Suppress -fvisibility if we have explicit visibility on any of

16
clang/test/CodeGenCXX/visibility.cpp
View File

@@ -20,6 +20,8 @@
// CHECK-HIDDEN: @_ZN6Test131C1aE = global
// CHECK: @_ZN6Test143varE = external global
// CHECK-HIDDEN: @_ZN6Test143varE = external global
// CHECK: @_ZN6Test154TempINS_1AEE5Inner6bufferE = external global [0 x i8]
// CHECK-HIDDEN: @_ZN6Test154TempINS_1AEE5Inner6bufferE = external global [0 x i8]
// CHECK: @_ZTVN5Test63fooE = weak_odr hidden constant
namespace Test1 {
@@ -218,3 +220,17 @@ namespace Test14 {
struct A *test() { return var; }
}
// rdar://problem/8613093
namespace Test15 {
struct A {};
template <class T> struct Temp {
struct Inner {
static char buffer[0];
};
};
char *test() {
return Temp<A>::Inner::buffer;
}
}