Switch the semantic DeclContext for a block-scope declaration of a function or
variable from being the function to being the enclosing namespace scope (in
C++) or the TU (in C). This allows us to fix a selection of related issues
where we would build incorrect redeclaration chains for such declarations, and
fail to notice type mismatches.
Such declarations are put into a new IdentifierNamespace, IDNS_LocalExtern,
which is only found when searching scopes, and not found when searching
DeclContexts. Such a declaration is only made visible in its DeclContext if
there are no non-LocalExtern declarations.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191064 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index c269606..a645986 100644
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -223,6 +223,8 @@
if (Redeclaration)
IDNS |= Decl::IDNS_TagFriend | Decl::IDNS_OrdinaryFriend;
}
+ if (Redeclaration)
+ IDNS |= Decl::IDNS_LocalExtern;
break;
case Sema::LookupOperatorName:
@@ -847,6 +849,26 @@
return std::make_pair(Lexical, false);
}
+namespace {
+/// An RAII object to specify that we want to find block scope extern
+/// declarations.
+struct FindLocalExternScope {
+ FindLocalExternScope(LookupResult &R)
+ : R(R), OldFindLocalExtern(R.getIdentifierNamespace() &
+ Decl::IDNS_LocalExtern) {
+ R.setFindLocalExtern(R.getIdentifierNamespace() & Decl::IDNS_Ordinary);
+ }
+ void restore() {
+ R.setFindLocalExtern(OldFindLocalExtern);
+ }
+ ~FindLocalExternScope() {
+ restore();
+ }
+ LookupResult &R;
+ bool OldFindLocalExtern;
+};
+}
+
bool Sema::CppLookupName(LookupResult &R, Scope *S) {
assert(getLangOpts().CPlusPlus && "Can perform only C++ lookup");
@@ -891,6 +913,10 @@
bool VisitedUsingDirectives = false;
bool LeftStartingScope = false;
DeclContext *OutsideOfTemplateParamDC = 0;
+
+ // When performing a scope lookup, we want to find local extern decls.
+ FindLocalExternScope FindLocals(R);
+
for (; S && !isNamespaceOrTranslationUnitScope(S); S = S->getParent()) {
DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity());
@@ -1046,7 +1072,12 @@
UDirs.visitScopeChain(Initial, S);
UDirs.done();
}
-
+
+ // If we're not performing redeclaration lookup, do not look for local
+ // extern declarations outside of a function scope.
+ if (!R.isForRedeclaration())
+ FindLocals.restore();
+
// Lookup namespace scope, and global scope.
// Unqualified name lookup in C++ requires looking into scopes
// that aren't strictly lexical, and therefore we walk through the
@@ -1292,6 +1323,9 @@
S = S->getParent();
}
+ // When performing a scope lookup, we want to find local extern decls.
+ FindLocalExternScope FindLocals(R);
+
// Scan up the scope chain looking for a decl that matches this
// identifier that is in the appropriate namespace. This search
// should not take long, as shadowing of names is uncommon, and
@@ -1361,6 +1395,7 @@
R.resolveKind();
}
+
return true;
}
} else {
@@ -2858,7 +2893,11 @@
NamedDecl *D = *I;
// If the only declaration here is an ordinary friend, consider
// it only if it was declared in an associated classes.
- if (D->getIdentifierNamespace() == Decl::IDNS_OrdinaryFriend) {
+ if ((D->getIdentifierNamespace() & Decl::IDNS_Ordinary) == 0) {
+ // If it's neither ordinarily visible nor a friend, we can't find it.
+ if ((D->getIdentifierNamespace() & Decl::IDNS_OrdinaryFriend) == 0)
+ continue;
+
bool DeclaredInAssociatedClass = false;
for (Decl *DI = D; DI; DI = DI->getPreviousDecl()) {
DeclContext *LexDC = DI->getLexicalDeclContext();
@@ -3160,6 +3199,7 @@
(!S->getParent() &&
!Visited.alreadyVisitedContext((DeclContext *)S->getEntity())) ||
((DeclContext *)S->getEntity())->isFunctionOrMethod()) {
+ FindLocalExternScope FindLocals(Result);
// Walk through the declarations in this Scope.
for (Scope::decl_iterator D = S->decl_begin(), DEnd = S->decl_end();
D != DEnd; ++D) {