Reland [LifetimeAnalysis] Support more STL idioms (template forward declaration and DependentNameType)

Reland after https://reviews.llvm.org/D66806 fixed the false-positive diagnostics.

Summary:
This fixes inference of gsl::Pointer on std::set::iterator with libstdc++ (the typedef for iterator
on the template is a DependentNameType - we can only put the gsl::Pointer attribute
on the underlaying record after instantiation)

inference of gsl::Pointer on std::vector::iterator with libc++ (the class was forward-declared,
we added the gsl::Pointer on the canonical decl (the forward decl), and later when the
template was instantiated, there was no attribute on the definition so it was not instantiated).

and a duplicate gsl::Pointer on some class with libstdc++ (we first added an attribute to
a incomplete instantiation, and then another was copied from the template definition
when the instantiation was completed).

We now add the attributes to all redeclarations to fix thos issues and make their usage easier.

Reviewers: gribozavr

Subscribers: Szelethus, xazax.hun, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66179

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@371182 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 7 deletions

diff --git a/lib/Sema/SemaAttr.cpp b/lib/Sema/SemaAttr.cpp
index e2542edf6e..23cb47481f 100644
--- a/lib/Sema/SemaAttr.cpp
+++ b/lib/Sema/SemaAttr.cpp
@@ -88,13 +88,11 @@ void Sema::AddMsStructLayoutForRecord(RecordDecl *RD) {
 template <typename Attribute>
 static void addGslOwnerPointerAttributeIfNotExisting(ASTContext &Context,
                                                      CXXRecordDecl *Record) {
-  CXXRecordDecl *Canonical = Record->getCanonicalDecl();
-  if (Canonical->hasAttr<OwnerAttr>() || Canonical->hasAttr<PointerAttr>())
+  if (Record->hasAttr<OwnerAttr>() || Record->hasAttr<PointerAttr>())
     return;
 
-  Canonical->addAttr(::new (Context) Attribute(SourceRange{}, Context,
-                                               /*DerefType*/ nullptr,
-                                               /*Spelling=*/0));
+  for (Decl *Redecl : Record->redecls())
+    Redecl->addAttr(Attribute::CreateImplicit(Context, /*DerefType=*/nullptr));
 }
 
 void Sema::inferGslPointerAttribute(NamedDecl *ND,
@@ -189,8 +187,7 @@ void Sema::inferGslOwnerPointerAttribute(CXXRecordDecl *Record) {
 
   // Handle classes that directly appear in std namespace.
   if (Record->isInStdNamespace()) {
-    CXXRecordDecl *Canonical = Record->getCanonicalDecl();
-    if (Canonical->hasAttr<OwnerAttr>() || Canonical->hasAttr<PointerAttr>())
+    if (Record->hasAttr<OwnerAttr>() || Record->hasAttr<PointerAttr>())
       return;
 
     if (StdOwners.count(Record->getName()))