Implement C++ [basic.link]p8.
If a function or variable has a type with no linkage (and is not extern "C"),
any use of it requires a definition within the same translation unit; the idea
is that it is not possible to define the entity elsewhere, so any such use is
necessarily an error.
There is an exception, though: some types formally have no linkage but
nonetheless can be referenced from other translation units (for example, this
happens to anonymous structures defined within inline functions). For entities
with those types, we suppress the diagnostic except under -pedantic.
llvm-svn: 313729
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 0a4c4a4..c3e3de1 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -721,8 +721,7 @@
// because of this, but unique-external linkage suits us.
if (Context.getLangOpts().CPlusPlus && !isFirstInExternCContext(Var)) {
LinkageInfo TypeLV = getLVForType(*Var->getType(), computation);
- if (TypeLV.getLinkage() != ExternalLinkage &&
- TypeLV.getLinkage() != ModuleLinkage)
+ if (!isExternallyVisible(TypeLV.getLinkage()))
return LinkageInfo::uniqueExternal();
if (!LV.isVisibilityExplicit())
LV.mergeVisibility(TypeLV);
@@ -772,7 +771,7 @@
QualType TypeAsWritten = Function->getType();
if (TypeSourceInfo *TSI = Function->getTypeSourceInfo())
TypeAsWritten = TSI->getType();
- if (TypeAsWritten->getLinkage() == UniqueExternalLinkage)
+ if (!isExternallyVisible(TypeAsWritten->getLinkage()))
return LinkageInfo::uniqueExternal();
}
@@ -909,7 +908,7 @@
const NamedDecl *explicitSpecSuppressor = nullptr;
if (const auto *MD = dyn_cast<CXXMethodDecl>(D)) {
- // If the type of the function uses a type with unique-external
+ // If the type of the function uses a type that has non-externally-visible
// linkage, it's not legally usable from outside this translation unit.
// But only look at the type-as-written. If this function has an
// auto-deduced return type, we can't compute the linkage of that type
@@ -922,7 +921,7 @@
QualType TypeAsWritten = MD->getType();
if (TypeSourceInfo *TSI = MD->getTypeSourceInfo())
TypeAsWritten = TSI->getType();
- if (TypeAsWritten->getLinkage() == UniqueExternalLinkage)
+ if (!isExternallyVisible(TypeAsWritten->getLinkage()))
return LinkageInfo::uniqueExternal();
}
// If this is a method template specialization, use the linkage for
@@ -1119,6 +1118,9 @@
Decl *ContextDecl,
LVComputationKind computation) {
// This lambda has its linkage/visibility determined by its owner.
+ // FIXME: This is wrong. A lambda never formally has linkage; if this
+ // calculation determines the lambda has external linkage, it should be
+ // downgraded to VisibleNoLinkage.
if (ContextDecl) {
if (isa<ParmVarDecl>(ContextDecl))
DC = ContextDecl->getDeclContext()->getRedeclContext();