make attribute instantiation instantiate all attributes

[rsmith]

Summary

Attribute instantiation would previously default to instantiating each kind of attribute only once. This was overridden by a flag whose intended purpose was to permit attributes from a prior declaration to be inherited onto a new declaration even if that new declaration had its own copy of the attribute. This appears to be the wrong behavior: when instantiating attributes from a template, we should always instantiate all the attributes that were written on that template.

This patch renames the flag in the Attr class (and TableGen sources) to more clearly identify what it's actually for, and removes the usage of the flag from template instantiation. I also removed the flag from AlignedAttr, which was only added to work around the seemingly-incorrect suppression of duplicate attribute instantiation.

[erichkeane]

Presumably this didn't break any tests, so I'm Ok with it. The initial patch was to make sure that template specializations could clear certain attributes, so I think this properly gets that done. The below test was apparently missed in the initial patch (and was the reason for the revert/restore), so perhaps this is something that could be validated still works as well. See comments here: https://reviews.llvm.org/rL298410

class Mutex {
public:

void Lock() __attribute__((exclusive_lock_function()));
void Unlock() __attribute__((unlock_function()));

};

class A {
public:

Mutex mu1, mu2;

void foo() __attribute__((exclusive_locks_required(mu1))) __attribute__((exclusive_locks_required(mu2))) {}

template <class T> void bar() __attribute__((exclusive_locks_required(mu1))) __attribute__((exclusive_locks_required(mu2))) {
  foo();
}

};

void f() {

A a;
a.mu1.Lock();
a.mu2.Lock();
a.bar<int>();
a.mu2.Unlock();
a.mu1.Unlock();

}

[aaron.ballman]

I don't suppose there is a chance at test coverage for this change?

include/clang/AST/Attr.h

142

I'm not too keen on the name -- perhaps isInheritedEvenIfAlreadyPresent()?

[rsmith]

In D41736#967552, @aaron.ballman wrote:

I don't suppose there is a chance at test coverage for this change?

Added Erich's test, plus a test that all instances of another attribute (annotate) get instantiated (the latter test failed prior to this change).

include/clang/AST/Attr.h

142

I started with that, but then changed to this abomination because isInherited[...] suggests it's telling you whether this attribute was inherited (like isInherited() does), which is not what it's for.

How about shouldInheritEvenIfAlreadyPresent?

[erichkeane]

LGTM, I like the shouldInheritEvenIfAlreadyPresent name better than isInherited... FWIW. I'll let @aaron.ballman make the final call though.

[aaron.ballman]

LGTM, thank you!

include/clang/AST/Attr.h

142

Sold!

[rsmith]

Committed as r321834.

include/clang/AST/Attr.h

 
 protected:
   /// An index into the spelling list of an
   /// attribute defined in Attr.td file.
   unsigned SpellingListIndex : 4;
   unsigned Inherited : 1;
   unsigned IsPackExpansion : 1;
   unsigned Implicit : 1;
+  // FIXME: These are properties of the attribute kind, not state for this
+  // instance of the attribute.
   unsigned IsLateParsed : 1;
-  unsigned DuplicatesAllowed : 1;
+  unsigned InheritEvenIfAlreadyPresent : 1;
 
   void *operator new(size_t bytes) noexcept {
     llvm_unreachable("Attrs cannot be allocated with regular 'new'.");
   }
   void operator delete(void *data) noexcept {
     llvm_unreachable("Attrs cannot be released with regular 'delete'.");
   }
 
 public:
   // Forward so that the regular new and delete do not hide global ones.
   void *operator new(size_t Bytes, ASTContext &C,
                      size_t Alignment = 8) noexcept {
     return ::operator new(Bytes, C, Alignment);
   }
   void operator delete(void *Ptr, ASTContext &C, size_t Alignment) noexcept {
     return ::operator delete(Ptr, C, Alignment);
   }
 
 protected:
   Attr(attr::Kind AK, SourceRange R, unsigned SpellingListIndex,
-       bool IsLateParsed, bool DuplicatesAllowed)
+       bool IsLateParsed)
     : Range(R), AttrKind(AK), SpellingListIndex(SpellingListIndex),
       Inherited(false), IsPackExpansion(false), Implicit(false),
-      IsLateParsed(IsLateParsed), DuplicatesAllowed(DuplicatesAllowed) {}
+      IsLateParsed(IsLateParsed), InheritEvenIfAlreadyPresent(false) {}
 
 public:
 
   attr::Kind getKind() const {
     return static_cast<attr::Kind>(AttrKind);
   }
   
   unsigned getSpellingListIndex() const { return SpellingListIndex; }
public:
 
   // Clone this attribute.
   Attr *clone(ASTContext &C) const;
 
   bool isLateParsed() const { return IsLateParsed; }
 
   // Pretty print this attribute.
   void printPretty(raw_ostream &OS, const PrintingPolicy &Policy) const;
-
-  /// \brief By default, attributes cannot be duplicated when being merged;
-  /// however, an attribute can override this. Returns true if the attribute
-  /// can be duplicated when merging.
-  bool duplicatesAllowed() const { return DuplicatesAllowed; }
 };
 
 class StmtAttr : public Attr {
 protected:
   StmtAttr(attr::Kind AK, SourceRange R, unsigned SpellingListIndex,
-                  bool IsLateParsed, bool DuplicatesAllowed)
-      : Attr(AK, R, SpellingListIndex, IsLateParsed, DuplicatesAllowed) {}
+                  bool IsLateParsed)
+      : Attr(AK, R, SpellingListIndex, IsLateParsed) {}
 
 public:
   static bool classof(const Attr *A) {
     return A->getKind() >= attr::FirstStmtAttr &&
            A->getKind() <= attr::LastStmtAttr;
   }
 };
 
 class InheritableAttr : public Attr {
 protected:
   InheritableAttr(attr::Kind AK, SourceRange R, unsigned SpellingListIndex,
-                  bool IsLateParsed, bool DuplicatesAllowed)
-      : Attr(AK, R, SpellingListIndex, IsLateParsed, DuplicatesAllowed) {}
+                  bool IsLateParsed, bool InheritEvenIfAlreadyPresent)
+      : Attr(AK, R, SpellingListIndex, IsLateParsed) {
+    this->InheritEvenIfAlreadyPresent = InheritEvenIfAlreadyPresent;
+  }
 
 public:
   void setInherited(bool I) { Inherited = I; }
 
+  /// Should this attribute be inherited from a prior declaration even if it's
+  /// explicitly provided in the current declaration?
+  bool shouldInheritEvenIfAlreadyPresent() const {
+    return InheritEvenIfAlreadyPresent;
+  }
+
   // Implement isa/cast/dyncast/etc.
   static bool classof(const Attr *A) {
     return A->getKind() >= attr::FirstInheritableAttr &&
            A->getKind() <= attr::LastInheritableAttr;
   }
 };
 
 class InheritableParamAttr : public InheritableAttr {
 protected:
   InheritableParamAttr(attr::Kind AK, SourceRange R, unsigned SpellingListIndex,
-                       bool IsLateParsed, bool DuplicatesAllowed)
+                       bool IsLateParsed, bool InheritEvenIfAlreadyPresent)
       : InheritableAttr(AK, R, SpellingListIndex, IsLateParsed,
-                        DuplicatesAllowed) {}
+                        InheritEvenIfAlreadyPresent) {}
 
 public:
   // Implement isa/cast/dyncast/etc.
   static bool classof(const Attr *A) {
     return A->getKind() >= attr::FirstInheritableParamAttr &&
            A->getKind() <= attr::LastInheritableParamAttr;
   }
 };
 
 /// A parameter attribute which changes the argument-passing ABI rule
 /// for the parameter.
 class ParameterABIAttr : public InheritableParamAttr {
 protected:
   ParameterABIAttr(attr::Kind AK, SourceRange R,
                    unsigned SpellingListIndex, bool IsLateParsed,
-                   bool DuplicatesAllowed)
+                   bool InheritEvenIfAlreadyPresent)
     : InheritableParamAttr(AK, R, SpellingListIndex, IsLateParsed,
-                           DuplicatesAllowed) {}
+                           InheritEvenIfAlreadyPresent) {}
 
 public:
   ParameterABI getABI() const {
     switch (getKind()) {
     case attr::SwiftContext:
       return ParameterABI::SwiftContext;
     case attr::SwiftErrorResult:
       return ParameterABI::SwiftErrorResult;

include/clang/Basic/Attr.td

class Attr {
   bit Ignored = 0;
   // Set to true if the attribute's parsing does not match its semantic
   // content. Eg) It parses 3 args, but semantically takes 4 args.  Opts out of
   // common attribute error checking.
   bit HasCustomParsing = 0;
   // Set to true if all of the attribute's arguments should be parsed in an
   // unevaluated context.
   bit ParseArgumentsAsUnevaluated = 0;
-  // Set to true if this attribute can be duplicated on a subject when merging
-  // attributes. By default, attributes are not merged.
-  bit DuplicatesAllowedWhileMerging = 0;
   // Set to true if this attribute meaningful when applied to or inherited 
   // in a class template definition.
   bit MeaningfulToClassTemplateDefinition = 0;
   // Set to true if this attribute can be used with '#pragma clang attribute'.
   // By default, when this value is false, an attribute is supported by the
   // '#pragma clang attribute' only when:
   // - It has documentation.
   // - It has a subject list whose subjects can be represented using subject
class TypeAttr : Attr {
   // By default, type attributes do not get an AST node.
   let ASTNode = 0;
 }
 
 /// A stmt attribute is not processed on a declaration or a type.
 class StmtAttr : Attr;
 
 /// An inheritable attribute is inherited by later redeclarations.
-class InheritableAttr : Attr;
+class InheritableAttr : Attr {
+  // Set to true if this attribute can be duplicated on a subject when inheriting
+  // attributes from prior declarations.
+  bit InheritEvenIfAlreadyPresent = 0;
+}
 
 /// A target-specific attribute.  This class is meant to be used as a mixin
 /// with InheritableAttr or Attr depending on the attribute's needs.
 class TargetSpecificAttr<TargetSpec target> {
   TargetSpec Target = target;
   // Attributes are generally required to have unique spellings for their names
   // so that the parser can determine what kind of attribute it has parsed.
   // However, target-specific attributes are special in that the attribute only
let Spellings = [GCC<"aligned">, Declspec<"align">, Keyword<"alignas">,
                    Keyword<"_Alignas">];
   let Args = [AlignedArgument<"Alignment", 1>];
   let Accessors = [Accessor<"isGNU", [GCC<"aligned">]>,
                    Accessor<"isC11", [Keyword<"_Alignas">]>,
                    Accessor<"isAlignas", [Keyword<"alignas">,
                                           Keyword<"_Alignas">]>,
                    Accessor<"isDeclspec",[Declspec<"align">]>];
   let Documentation = [Undocumented];
-  let DuplicatesAllowedWhileMerging = 1;
 }
 
 def AlignValue : Attr {
   let Spellings = [
     // Unfortunately, this is semantically an assertion, not a directive
     // (something else must ensure the alignment), so aligned_value is a
     // probably a better name. We might want to add an aligned_value spelling in
     // the future (and a corresponding C++ attribute), but this can be done
return llvm::StringSwitch<llvm::StringRef>(Platform)
              .Case("watchOS", "watchos")
              .Case("iOSApplicationExtension", "ios_app_extension")
              .Case("macOSApplicationExtension", "macos_app_extension")
              .Case("tvOSApplicationExtension", "tvos_app_extension")
              .Case("watchOSApplicationExtension", "watchos_app_extension")
              .Default(Platform);
 } }];
   let HasCustomParsing = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Named]>;
   let Documentation = [AvailabilityDocs];
 }
 
 def ExternalSourceSymbol : InheritableAttr {
   let Spellings = [Clang<"external_source_symbol">];
   let Args = [StringArgument<"language", 1>,
               StringArgument<"definedIn", 1>,
[{bool isNonNull(unsigned idx) const {
     if (!args_size())
       return true;
     for (const auto &V : args())
       if (V == idx)
         return true;
     return false;
   } }];
   // FIXME: We should merge duplicates into a single nonnull attribute.
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Documentation = [NonNullDocs];
 }
 
 def ReturnsNonNull : InheritableAttr {
   let Spellings = [GCC<"returns_nonnull">];
   let Subjects = SubjectList<[ObjCMethod, Function]>;
   let Documentation = [ReturnsNonNullDocs];
 }
def DiagnoseIf : InheritableAttr {
   let Subjects = SubjectList<[Function, ObjCMethod, ObjCProperty]>;
   let Args = [ExprArgument<"Cond">, StringArgument<"Message">,
               EnumArgument<"DiagnosticType",
                            "DiagnosticType",
                            ["error", "warning"],
                            ["DT_Error", "DT_Warning"]>,
               BoolArgument<"ArgDependent", 0, /*fake*/ 1>,
               NamedArgument<"Parent", 0, /*fake*/ 1>];
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let LateParsed = 1;
   let AdditionalMembers = [{
     bool isError() const { return diagnosticType == DT_Error; }
     bool isWarning() const { return diagnosticType == DT_Warning; }
   }];
   let TemplateDependent = 1;
   let Documentation = [DiagnoseIfDocs];
 }

 
 def AssertCapability : InheritableAttr {
   let Spellings = [Clang<"assert_capability">,
                    Clang<"assert_shared_capability">];
   let Subjects = SubjectList<[Function]>;
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Args = [VariadicExprArgument<"Args">];
   let Accessors = [Accessor<"isShared",
                     [Clang<"assert_shared_capability">]>];
   let Documentation = [AssertCapabilityDocs];
 }
 
 def AcquireCapability : InheritableAttr {
   let Spellings = [Clang<"acquire_capability">,
                    Clang<"acquire_shared_capability">,
                    GNU<"exclusive_lock_function">,
                    GNU<"shared_lock_function">];
   let Subjects = SubjectList<[Function]>;
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Args = [VariadicExprArgument<"Args">];
   let Accessors = [Accessor<"isShared",
                     [Clang<"acquire_shared_capability">,
                      GNU<"shared_lock_function">]>];
   let Documentation = [AcquireCapabilityDocs];
 }
 
 def TryAcquireCapability : InheritableAttr {
   let Spellings = [Clang<"try_acquire_capability">,
                    Clang<"try_acquire_shared_capability">];
   let Subjects = SubjectList<[Function],
                              ErrorDiag>;
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Args = [ExprArgument<"SuccessValue">, VariadicExprArgument<"Args">];
   let Accessors = [Accessor<"isShared",
                     [Clang<"try_acquire_shared_capability">]>];
   let Documentation = [TryAcquireCapabilityDocs];
 }
 
 def ReleaseCapability : InheritableAttr {
   let Spellings = [Clang<"release_capability">,
                    Clang<"release_shared_capability">,
                    Clang<"release_generic_capability">,
                    Clang<"unlock_function">];
   let Subjects = SubjectList<[Function]>;
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Args = [VariadicExprArgument<"Args">];
   let Accessors = [Accessor<"isShared",
                     [Clang<"release_shared_capability">]>,
                    Accessor<"isGeneric",
                      [Clang<"release_generic_capability">,
                       Clang<"unlock_function">]>];
   let Documentation = [ReleaseCapabilityDocs];
 }
 
 def RequiresCapability : InheritableAttr {
   let Spellings = [Clang<"requires_capability">,
                    Clang<"exclusive_locks_required">,
                    Clang<"requires_shared_capability">,
                    Clang<"shared_locks_required">];
   let Args = [VariadicExprArgument<"Args">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Function]>;
   let Accessors = [Accessor<"isShared", [Clang<"requires_shared_capability">,
                                          Clang<"shared_locks_required">]>];
   let Documentation = [Undocumented];
 }
 
 def NoThreadSafetyAnalysis : InheritableAttr {
   let Spellings = [Clang<"no_thread_safety_analysis">];
   let Subjects = SubjectList<[Function]>;
   let Documentation = [Undocumented];
 }
 
 def GuardedBy : InheritableAttr {
   let Spellings = [GNU<"guarded_by">];
   let Args = [ExprArgument<"Arg">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Field, SharedVar]>;
   let Documentation = [Undocumented];
 }
 
 def PtGuardedBy : InheritableAttr {
   let Spellings = [GNU<"pt_guarded_by">];
   let Args = [ExprArgument<"Arg">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Field, SharedVar]>;
   let Documentation = [Undocumented];
 }
 
 def AcquiredAfter : InheritableAttr {
   let Spellings = [GNU<"acquired_after">];
   let Args = [VariadicExprArgument<"Args">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Field, SharedVar]>;
   let Documentation = [Undocumented];
 }
 
 def AcquiredBefore : InheritableAttr {
   let Spellings = [GNU<"acquired_before">];
   let Args = [VariadicExprArgument<"Args">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Field, SharedVar]>;
   let Documentation = [Undocumented];
 }
 
 def AssertExclusiveLock : InheritableAttr {
   let Spellings = [GNU<"assert_exclusive_lock">];
   let Args = [VariadicExprArgument<"Args">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Function]>;
   let Documentation = [Undocumented];
 }
 
 def AssertSharedLock : InheritableAttr {
   let Spellings = [GNU<"assert_shared_lock">];
   let Args = [VariadicExprArgument<"Args">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Function]>;
   let Documentation = [Undocumented];
 }
 
 // The first argument is an integer or boolean value specifying the return value
 // of a successful lock acquisition.
 def ExclusiveTrylockFunction : InheritableAttr {
   let Spellings = [GNU<"exclusive_trylock_function">];
   let Args = [ExprArgument<"SuccessValue">, VariadicExprArgument<"Args">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Function]>;
   let Documentation = [Undocumented];
 }
 
 // The first argument is an integer or boolean value specifying the return value
 // of a successful lock acquisition.
 def SharedTrylockFunction : InheritableAttr {
   let Spellings = [GNU<"shared_trylock_function">];
   let Args = [ExprArgument<"SuccessValue">, VariadicExprArgument<"Args">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Function]>;
   let Documentation = [Undocumented];
 }
 
 def LockReturned : InheritableAttr {
   let Spellings = [GNU<"lock_returned">];
   let Args = [ExprArgument<"Arg">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
   let Subjects = SubjectList<[Function]>;
   let Documentation = [Undocumented];
 }
 
 def LocksExcluded : InheritableAttr {
   let Spellings = [GNU<"locks_excluded">];
   let Args = [VariadicExprArgument<"Args">];
   let LateParsed = 1;
   let TemplateDependent = 1;
   let ParseArgumentsAsUnevaluated = 1;
-  let DuplicatesAllowedWhileMerging = 1;
+  let InheritEvenIfAlreadyPresent = 1;
   let Subjects = SubjectList<[Function]>;
   let Documentation = [Undocumented];
 }
 
 // C/C++ consumed attributes.
 
 def Consumable : InheritableAttr {
   let Spellings = [Clang<"consumable">];

lib/Sema/SemaDecl.cpp

else if (isa<AlignedAttr>(Attr))
     NewAttr = nullptr;
   else if ((isa<DeprecatedAttr>(Attr) || isa<UnavailableAttr>(Attr)) &&
            (AMK == Sema::AMK_Override ||
             AMK == Sema::AMK_ProtocolImplementation))
     NewAttr = nullptr;
   else if (const auto *UA = dyn_cast<UuidAttr>(Attr))
     NewAttr = S.mergeUuidAttr(D, UA->getRange(), AttrSpellingListIndex,
                               UA->getGuid());
-  else if (Attr->duplicatesAllowed() || !DeclHasAttr(D, Attr))
+  else if (Attr->shouldInheritEvenIfAlreadyPresent() || !DeclHasAttr(D, Attr))
     NewAttr = cast<InheritableAttr>(Attr->clone(S.Context));
 
   if (NewAttr) {
     NewAttr->setInherited(true);
     D->addAttr(NewAttr);
     if (isa<MSInheritanceAttr>(NewAttr))
       S.Consumer.AssignInheritanceModel(cast<CXXRecordDecl>(D));
     return true;

lib/Sema/SemaTemplateInstantiateDecl.cpp

static void instantiateOMPDeclareSimdDeclAttr(
   }
   LinModifiers.append(Attr.modifiers_begin(), Attr.modifiers_end());
   (void)S.ActOnOpenMPDeclareSimdDirective(
       S.ConvertDeclToDeclGroup(New), Attr.getBranchState(), Simdlen.get(),
       Uniforms, Aligneds, Alignments, Linears, LinModifiers, Steps,
       Attr.getRange());
 }
 
-static bool DeclContainsAttr(const Decl *D, const Attr *NewAttr) {
-  if (!D->hasAttrs() || NewAttr->duplicatesAllowed())
-    return false;
-  return llvm::find_if(D->getAttrs(), [NewAttr](const Attr *Attr) {
-           return Attr->getKind() == NewAttr->getKind();
-         }) != D->getAttrs().end();
-}
-
 void Sema::InstantiateAttrsForDecl(
     const MultiLevelTemplateArgumentList &TemplateArgs, const Decl *Tmpl,
     Decl *New, LateInstantiatedAttrVec *LateAttrs,
     LocalInstantiationScope *OuterMostScope) {
   if (NamedDecl *ND = dyn_cast<NamedDecl>(New)) {
     for (const auto *TmplAttr : Tmpl->attrs()) {
       // FIXME: If any of the special case versions from InstantiateAttrs become
       // applicable to template declaration, we'll need to add them here.
       CXXThisScopeRAII ThisScope(
           *this, dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext()),
           /*TypeQuals*/ 0, ND->isCXXInstanceMember());
 
       Attr *NewAttr = sema::instantiateTemplateAttributeForDecl(
           TmplAttr, Context, *this, TemplateArgs);
-      if (NewAttr && !DeclContainsAttr(New, NewAttr))
+      if (NewAttr)
         New->addAttr(NewAttr);
     }
   }
 }
 
 void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
                             const Decl *Tmpl, Decl *New,
                             LateInstantiatedAttrVec *LateAttrs,
if (TmplAttr->isLateParsed() && LateAttrs) {
       NamedDecl *ND = dyn_cast<NamedDecl>(New);
       CXXRecordDecl *ThisContext =
           dyn_cast_or_null<CXXRecordDecl>(ND->getDeclContext());
       CXXThisScopeRAII ThisScope(*this, ThisContext, /*TypeQuals*/0,
                                  ND && ND->isCXXInstanceMember());
 
       Attr *NewAttr = sema::instantiateTemplateAttribute(TmplAttr, Context,
                                                          *this, TemplateArgs);
-
-      if (NewAttr && !DeclContainsAttr(New, NewAttr))
+      if (NewAttr)
         New->addAttr(NewAttr);
     }
   }
 }
 
 /// Get the previous declaration of a declaration for the purposes of template
 /// instantiation. If this finds a previous declaration, then the previous
 /// declaration of the instantiation of D should be an instantiation of the

test/SemaTemplate/attributes.cpp

 // RUN: %clang_cc1 -std=gnu++11 -fsyntax-only -verify %s
+// RUN: not %clang_cc1 -std=gnu++11 -ast-dump %s | FileCheck %s
 
 namespace attribute_aligned {
   template<int N>
   struct X {
     char c[1] __attribute__((__aligned__((N)))); // expected-error {{alignment is not a power of 2}}
   };
 
   template <bool X> struct check {
namespace PR9049 {
   inline T WBCFRetain(T aValue) { return aValue ? (T)CFRetain(aValue) : (T)0; }
 
 
   extern void CFRelease(const void *ref);
 
   template<typename T>
   inline void WBCFRelease(__attribute__((cf_consumed)) T aValue) { if(aValue) CFRelease(aValue); }
 }
+
+// CHECK: FunctionTemplateDecl {{.*}} HasAnnotations
+// CHECK:   AnnotateAttr {{.*}} "ANNOTATE_BAR"
+// CHECK:   AnnotateAttr {{.*}} "ANNOTATE_FOO"
+// CHECK: FunctionDecl {{.*}} HasAnnotations
+// CHECK:   TemplateArgument type 'int'
+// CHECK:   AnnotateAttr {{.*}} "ANNOTATE_BAR"
+// CHECK:   AnnotateAttr {{.*}} "ANNOTATE_FOO"
+template<typename T> [[clang::annotate("ANNOTATE_FOO"), clang::annotate("ANNOTATE_BAR")]] void HasAnnotations();
+void UseAnnotations() { HasAnnotations<int>(); }

test/SemaTemplate/warn-thread-safety-analysis.cpp

+// RUN: %clang_cc1 -std=c++11 %s -verify -Wthread-safety-analysis
+
+class Mutex {
+public:
+  void Lock() __attribute__((exclusive_lock_function()));
+  void Unlock() __attribute__((unlock_function()));
+};
+
+class A {
+public:
+  Mutex mu1, mu2;
+
+  void foo() __attribute__((exclusive_locks_required(mu1))) __attribute__((exclusive_locks_required(mu2))) {}
+
+  template <class T> void bar() __attribute__((exclusive_locks_required(mu1))) __attribute__((exclusive_locks_required(mu2))) {
+    foo();
+  }
+};
+
+void f() {
+  A a;
+  a.mu1.Lock();
+  a.mu2.Lock();
+  a.bar<int>();
+  a.mu2.Unlock();
+  a.bar<int>(); // expected-warning {{calling function 'bar' requires holding mutex 'a.mu2' exclusively}}
+  a.mu1.Unlock();
+  a.bar<int>(); // expected-warning {{calling function 'bar' requires holding mutex 'a.mu1' exclusively}} \
+                   expected-warning {{calling function 'bar' requires holding mutex 'a.mu2' exclusively}}
+}

utils/TableGen/ClangAttrEmitter.cpp

for (const auto *Attr : Attrs) {
     (void)R.getValueAsListOfDefs("Documentation");
     
     if (!R.getValueAsBit("ASTNode"))
       continue;
     
     ArrayRef<std::pair<Record *, SMRange>> Supers = R.getSuperClasses();
     assert(!Supers.empty() && "Forgot to specify a superclass for the attr");
     std::string SuperName;
+    bool Inheritable = false;
     for (const auto &Super : llvm::reverse(Supers)) {
       const Record *R = Super.first;
       if (R->getName() != "TargetSpecificAttr" && SuperName.empty())
         SuperName = R->getName();
+      if (R->getName() == "InheritableAttr")
+        Inheritable = true;
     }
 
     OS << "class " << R.getName() << "Attr : public " << SuperName << " {\n";
 
     std::vector<Record*> ArgRecords = R.getValueAsListOfDefs("Args");
     std::vector<std::unique_ptr<Argument>> Args;
     Args.reserve(ArgRecords.size());
 
auto emitCtor = [&](bool emitOpt, bool emitFake) {
         OS << "\n";
       }
 
       OS << "              , ";
       OS << "unsigned SI\n";
 
       OS << "             )\n";
       OS << "    : " << SuperName << "(attr::" << R.getName() << ", R, SI, "
-         << ( R.getValueAsBit("LateParsed") ? "true" : "false" ) << ", "
-         << ( R.getValueAsBit("DuplicatesAllowedWhileMerging") ? "true" : "false" ) << ")\n";
+         << ( R.getValueAsBit("LateParsed") ? "true" : "false" );
+      if (Inheritable) {
+        OS << ", "
+           << (R.getValueAsBit("InheritEvenIfAlreadyPresent") ? "true"
+                                                              : "false");
+      }
+      OS << ")\n";
 
       for (auto const &ai : Args) {
         OS << "              , ";
         if (!shouldEmitArg(ai)) {
           ai->writeCtorDefaultInitializers(OS);
         } else {
           ai->writeCtorInitializers(OS);
         }