[clang] Add a common definition of isPointerLikeType for lifetime analysis (#117315)

Also checks for annotation for template specializations which sometimes
may not have the annotation attached.

Author: usx95

clang/lib/Sema/CheckExprLifetime.cpp

@@ -9,6 +9,7 @@
 #include "CheckExprLifetime.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/Expr.h"
+#include "clang/AST/Type.h"
 #include "clang/Basic/DiagnosticSema.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Sema.h"
@@ -253,9 +254,17 @@ static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
                                                   LocalVisitor Visit);
 
 template <typename T> static bool isRecordWithAttr(QualType Type) {
-  if (auto *RD = Type->getAsCXXRecordDecl())
-    return RD->hasAttr<T>();
-  return false;
+  auto *RD = Type->getAsCXXRecordDecl();
+  if (!RD)
+    return false;
+  if (auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(RD))
+    RD = CTSD->getSpecializedTemplate()->getTemplatedDecl();
+  return RD->hasAttr<T>();
+}
+
+bool isPointerLikeType(QualType QT) {
+  return isRecordWithAttr<PointerAttr>(QT) || QT->isPointerType() ||
+         QT->isNullPtrType();
 }
 
 // Decl::isInStdNamespace will return false for iterators in some STL
@@ -276,11 +285,6 @@ static bool isInStlNamespace(const Decl *D) {
   return DC->isStdNamespace();
 }
 
-static bool isPointerLikeType(QualType Type) {
-  return isRecordWithAttr<PointerAttr>(Type) || Type->isPointerType() ||
-         Type->isNullPtrType();
-}
-
 // Returns true if the given Record decl is a form of `GSLOwner<Pointer>`
 // type, e.g. std::vector<string_view>, std::optional<string_view>.
 static bool isContainerOfPointer(const RecordDecl *Container) {

clang/lib/Sema/CheckExprLifetime.h

@@ -18,6 +18,10 @@
 
 namespace clang::sema {
 
+// Tells whether the type is annotated with [[gsl::Pointer]] or is a pointer
+// type.
+bool isPointerLikeType(QualType QT);
+
 /// Describes an entity that is being assigned.
 struct AssignedEntity {
   // The left-hand side expression of the assignment.

clang/lib/Sema/SemaAttr.cpp

@@ -269,18 +269,6 @@ void Sema::inferLifetimeBoundAttribute(FunctionDecl *FD) {
   }
 }
 
-static bool isPointerLikeType(QualType QT) {
-  QT = QT.getNonReferenceType();
-  if (QT->isPointerType())
-    return true;
-  auto *RD = QT->getAsCXXRecordDecl();
-  if (!RD)
-    return false;
-  if (auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(RD))
-    RD = CTSD->getSpecializedTemplate()->getTemplatedDecl();
-  return RD->hasAttr<PointerAttr>();
-}
-
 void Sema::inferLifetimeCaptureByAttribute(FunctionDecl *FD) {
   if (!FD)
     return;
@@ -299,7 +287,7 @@ void Sema::inferLifetimeCaptureByAttribute(FunctionDecl *FD) {
     if (PVD->hasAttr<LifetimeCaptureByAttr>())
       return;
   for (ParmVarDecl *PVD : MD->parameters()) {
-    if (isPointerLikeType(PVD->getType())) {
+    if (sema::isPointerLikeType(PVD->getType().getNonReferenceType())) {
       int CaptureByThis[] = {LifetimeCaptureByAttr::THIS};
       PVD->addAttr(
           LifetimeCaptureByAttr::CreateImplicit(Context, CaptureByThis, 1));