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

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()))

lib/Sema/SemaDeclAttr.cpp

@@ -4592,9 +4592,11 @@ static void handleLifetimeCategoryAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
       }
       return;
     }
-    D->addAttr(::new (S.Context)
-                   OwnerAttr(AL.getRange(), S.Context, DerefTypeLoc,
-                             AL.getAttributeSpellingListIndex()));
+    for (Decl *Redecl : D->redecls()) {
+      Redecl->addAttr(::new (S.Context)
+                          OwnerAttr(AL.getRange(), S.Context, DerefTypeLoc,
+                                    AL.getAttributeSpellingListIndex()));
+    }
   } else {
     if (checkAttrMutualExclusion<OwnerAttr>(S, D, AL))
       return;
@@ -4609,9 +4611,11 @@ static void handleLifetimeCategoryAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
       }
       return;
     }
-    D->addAttr(::new (S.Context)
-                   PointerAttr(AL.getRange(), S.Context, DerefTypeLoc,
-                               AL.getAttributeSpellingListIndex()));
+    for (Decl *Redecl : D->redecls()) {
+      Redecl->addAttr(::new (S.Context)
+                          PointerAttr(AL.getRange(), S.Context, DerefTypeLoc,
+                                      AL.getAttributeSpellingListIndex()));
+    }
   }
 }
 

lib/Sema/SemaInit.cpp

@@ -6693,7 +6693,7 @@ static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
 
 template <typename T> static bool isRecordWithAttr(QualType Type) {
   if (auto *RD = Type->getAsCXXRecordDecl())
-    return RD->getCanonicalDecl()->hasAttr<T>();
+    return RD->hasAttr<T>();
   return false;
 }
 
@@ -6810,7 +6810,7 @@ static void handleGslAnnotatedTypes(IndirectLocalPath &Path, Expr *Call,
 
   if (auto *CCE = dyn_cast<CXXConstructExpr>(Call)) {
     const auto *Ctor = CCE->getConstructor();
-    const CXXRecordDecl *RD = Ctor->getParent()->getCanonicalDecl();
+    const CXXRecordDecl *RD = Ctor->getParent();
     if (CCE->getNumArgs() > 0 && RD->hasAttr<PointerAttr>())
       VisitPointerArg(Ctor->getParamDecl(0), CCE->getArgs()[0]);
   }

lib/Sema/SemaTemplateInstantiateDecl.cpp

@@ -550,6 +550,18 @@ void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
       continue;
     }
 
+    if (auto *A = dyn_cast<PointerAttr>(TmplAttr)) {
+      if (!New->hasAttr<PointerAttr>())
+        New->addAttr(A->clone(Context));
+      continue;
+    }
+
+    if (auto *A = dyn_cast<OwnerAttr>(TmplAttr)) {
+      if (!New->hasAttr<OwnerAttr>())
+        New->addAttr(A->clone(Context));
+      continue;
+    }
+
     assert(!TmplAttr->isPackExpansion());
     if (TmplAttr->isLateParsed() && LateAttrs) {
       // Late parsed attributes must be instantiated and attached after the
@@ -709,6 +721,9 @@ Decl *TemplateDeclInstantiator::InstantiateTypedefNameDecl(TypedefNameDecl *D,
 
   SemaRef.InstantiateAttrs(TemplateArgs, D, Typedef);
 
+  if (D->getUnderlyingType()->getAs<DependentNameType>())
+    SemaRef.inferGslPointerAttribute(Typedef);
+
   Typedef->setAccess(D->getAccess());
 
   return Typedef;

test/SemaCXX/attr-gsl-owner-pointer-std.cpp

@@ -92,6 +92,59 @@ public:
 static_assert(sizeof(unordered_map<int>::iterator), ""); // Force instantiation.
 } // namespace inlinens
 
+// The iterator typedef is a DependentNameType.
+template <typename T>
+class __unordered_multimap_iterator {};
+// CHECK: ClassTemplateDecl {{.*}} __unordered_multimap_iterator
+// CHECK: ClassTemplateSpecializationDecl {{.*}} __unordered_multimap_iterator
+// CHECK: TemplateArgument type 'int'
+// CHECK: PointerAttr
+
+template <typename T>
+class __unordered_multimap_base {
+public:
+  using iterator = __unordered_multimap_iterator<T>;
+};
+
+template <typename T>
+class unordered_multimap {
+  // CHECK: ClassTemplateDecl {{.*}} unordered_multimap
+  // CHECK: OwnerAttr {{.*}}
+  // CHECK: ClassTemplateSpecializationDecl {{.*}} unordered_multimap
+  // CHECK: OwnerAttr {{.*}}
+public:
+  using _Mybase = __unordered_multimap_base<T>;
+  using iterator = typename _Mybase::iterator;
+};
+static_assert(sizeof(unordered_multimap<int>::iterator), ""); // Force instantiation.
+
+// The canonical declaration of the iterator template is not its definition.
+template <typename T>
+class __unordered_multiset_iterator;
+// CHECK: ClassTemplateDecl {{.*}} __unordered_multiset_iterator
+// CHECK: PointerAttr
+// CHECK: ClassTemplateSpecializationDecl {{.*}} __unordered_multiset_iterator
+// CHECK: TemplateArgument type 'int'
+// CHECK: PointerAttr
+
+template <typename T>
+class __unordered_multiset_iterator {
+  // CHECK: ClassTemplateDecl {{.*}} prev {{.*}} __unordered_multiset_iterator
+  // CHECK: PointerAttr
+};
+
+template <typename T>
+class unordered_multiset {
+  // CHECK: ClassTemplateDecl {{.*}} unordered_multiset
+  // CHECK: OwnerAttr {{.*}}
+  // CHECK: ClassTemplateSpecializationDecl {{.*}} unordered_multiset
+  // CHECK: OwnerAttr {{.*}}
+public:
+  using iterator = __unordered_multiset_iterator<T>;
+};
+
+static_assert(sizeof(unordered_multiset<int>::iterator), ""); // Force instantiation.
+
 // std::list has an implicit gsl::Owner attribute,
 // but explicit attributes take precedence.
 template <typename T>

test/SemaCXX/attr-gsl-owner-pointer.cpp

@@ -105,3 +105,20 @@ class [[gsl::Owner(int)]] AddTheSameLater{};
 class [[gsl::Owner(int)]] AddTheSameLater;
 // CHECK: CXXRecordDecl {{.*}} prev {{.*}} AddTheSameLater
 // CHECK: OwnerAttr {{.*}} int
+
+template <class T>
+class [[gsl::Owner]] ForwardDeclared;
+// CHECK: ClassTemplateDecl {{.*}} ForwardDeclared
+// CHECK: OwnerAttr {{.*}}
+// CHECK: ClassTemplateSpecializationDecl {{.*}} ForwardDeclared
+// CHECK: TemplateArgument type 'int'
+// CHECK: OwnerAttr {{.*}}
+
+template <class T>
+class [[gsl::Owner]] ForwardDeclared {
+// CHECK: ClassTemplateDecl {{.*}} ForwardDeclared
+// CHECK: CXXRecordDecl {{.*}} ForwardDeclared definition
+// CHECK: OwnerAttr {{.*}}
+};
+
+static_assert(sizeof(ForwardDeclared<int>), ""); // Force instantiation.

unittests/Sema/CMakeLists.txt

@@ -5,11 +5,13 @@ set(LLVM_LINK_COMPONENTS
 add_clang_unittest(SemaTests
   ExternalSemaSourceTest.cpp
   CodeCompleteTest.cpp
+  GslOwnerPointerInference.cpp
   )
 
 clang_target_link_libraries(SemaTests
   PRIVATE
   clangAST
+  clangASTMatchers
   clangBasic
   clangFrontend
   clangParse

unittests/Sema/GslOwnerPointerInference.cpp

@@ -0,0 +1,61 @@
+//== unittests/Sema/GslOwnerPointerInference.cpp - gsl::Owner/Pointer ========//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "../ASTMatchers/ASTMatchersTest.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "gtest/gtest.h"
+
+namespace clang {
+using namespace ast_matchers;
+
+TEST(OwnerPointer, BothHaveAttributes) {
+  EXPECT_TRUE(matches(
+    R"cpp(
+      template<class T>
+      class [[gsl::Owner]] C;
+
+      template<class T>
+      class [[gsl::Owner]] C {};
+
+      C<int> c;
+  )cpp",
+    classTemplateSpecializationDecl(hasName("C"), hasAttr(clang::attr::Owner))));
+}
+
+TEST(OwnerPointer, ForwardDeclOnly) {
+  EXPECT_TRUE(matches(
+    R"cpp(
+      template<class T>
+      class [[gsl::Owner]] C;
+
+      template<class T>
+      class C {};
+
+      C<int> c;
+  )cpp",
+    classTemplateSpecializationDecl(hasName("C"), hasAttr(clang::attr::Owner))));
+}
+
+TEST(OwnerPointer, LateForwardDeclOnly) {
+  EXPECT_TRUE(matches(
+    R"cpp(
+      template<class T>
+      class C;
+
+      template<class T>
+      class C {};
+
+      template<class T>
+      class [[gsl::Owner]] C;
+
+      C<int> c;
+  )cpp",
+    classTemplateSpecializationDecl(hasName("C"), hasAttr(clang::attr::Owner))));
+}
+
+} // namespace clang