PR27132: Proper mangling for __unaligned qualifier (now with both PR27367 and PR27666 fixed)

[andreybokhanko]

Summary

This is exactly same patch as http://reviews.llvm.org/D19654 (already reviewed and LGTMed by majnemer), with a couple of changes to fix PR27666:

• __unaligned is not considered when checking type compatibility in CompareReferenceRelationship and TryReferenceInit, as MS compiler does the same (and qos2.h header relies on this)
• Test from PR27666 added to SemaCXX/MicrosoftExtensions.cpp

I verified the patch on a huge selection of Windows headers (including qos2.h), so hopefully there will be no more reverts! :-)

Yours,

Andrey

Software Engineer
Intel Compiler Team

[majnemer]

Can we test pointers to data members? Is it possible to have __unaligned int *S::* or int *S::* __unaligned or even __unaligned int *S::* __unaligned ?

include/clang/AST/Type.h

446

Could this be !other.hasUnaligned() || hasUnaligned() ?

5393

Variables should be capitalized.

lib/Sema/SemaType.cpp

2681

If this was a ranged-for over Fixits, we wouldn't need to keep updating the loop bounds.

[andreybokhanko]

Patch updated to address David's comments.

Yours,
Andrey

[andreybokhanko]

In D20103#425855, @majnemer wrote:

Can we test pointers to data members? Is it possible to have __unaligned int *S::* or int *S::* __unaligned or even __unaligned int *S::* __unaligned ?

I added these three cases to MicrosoftExtensions.cpp. We behave exactly like MS compiler: allow all three usages, disallow assignment of an unaligned pointer to a non-unaligned one.

include/clang/AST/Type.h

446

Fixed

5393–5400

Fixed

lib/Sema/SemaType.cpp

2680–2682

Fixed

[majnemer]

LGTM, thanks!

include/clang/AST/Type.h

namespace clang {
 
   // Provide forward declarations for all of the *Type classes
 #define TYPE(Class, Base) class Class##Type;
 #include "clang/AST/TypeNodes.def"
 
 /// The collection of all-type qualifiers we support.
 /// Clang supports five independent qualifiers:
 /// * C99: const, volatile, and restrict
+/// * MS: __unaligned
 /// * Embedded C (TR18037): address spaces
 /// * Objective C: the GC attributes (none, weak, or strong)
 class Qualifiers {
 public:
   enum TQ { // NOTE: These flags must be kept in sync with DeclSpec::TQ.
     Const    = 0x1,
     Restrict = 0x2,
     Volatile = 0x4,
enum ObjCLifetime {
     OCL_Weak,
 
     /// Assigning into this object requires a lifetime extension.
     OCL_Autoreleasing
   };
 
   enum {
     /// The maximum supported address space number.
-    /// 24 bits should be enough for anyone.
-    MaxAddressSpace = 0xffffffu,
+    /// 23 bits should be enough for anyone.
+    MaxAddressSpace = 0x7fffffu,
 
     /// The width of the "fast" qualifier mask.
     FastWidth = 3,
 
     /// The fast qualifier mask.
     FastMask = (1 << FastWidth) - 1
   };
 
public:
   void removeCVRQualifiers() {
     removeCVRQualifiers(CVRMask);
   }
   void addCVRQualifiers(unsigned mask) {
     assert(!(mask & ~CVRMask) && "bitmask contains non-CVR bits");
     Mask |= mask;
   }
 
+  bool hasUnaligned() const { return Mask & UMask; }
+  void setUnaligned(bool flag) {
+    Mask = (Mask & ~UMask) | (flag ? UMask : 0);
+  }
+  void removeUnaligned() { Mask &= ~UMask; }
+  void addUnaligned() { Mask |= UMask; }
+
   bool hasObjCGCAttr() const { return Mask & GCAttrMask; }
   GC getObjCGCAttr() const { return GC((Mask & GCAttrMask) >> GCAttrShift); }
   void setObjCGCAttr(GC type) {
     Mask = (Mask & ~GCAttrMask) | (type << GCAttrShift);
   }
   void removeObjCGCAttr() { setObjCGCAttr(GCNone); }
   void addObjCGCAttr(GC type) {
     assert(type);
bool compatiblyIncludes(Qualifiers other) const {
     return isAddressSpaceSupersetOf(other) &&
            // ObjC GC qualifiers can match, be added, or be removed, but can't
            // be changed.
            (getObjCGCAttr() == other.getObjCGCAttr() || !hasObjCGCAttr() ||
             !other.hasObjCGCAttr()) &&
            // ObjC lifetime qualifiers must match exactly.
            getObjCLifetime() == other.getObjCLifetime() &&
            // CVR qualifiers may subset.
-           (((Mask & CVRMask) | (other.Mask & CVRMask)) == (Mask & CVRMask));
+           (((Mask & CVRMask) | (other.Mask & CVRMask)) == (Mask & CVRMask)) &&
+           // U qualifier may superset.
+           (!(other.Mask & UMask) || (Mask & UMask));
   }
 
   /// \brief Determines if these qualifiers compatibly include another set of
   /// qualifiers from the narrow perspective of Objective-C ARC lifetime.
   ///
   /// One set of Objective-C lifetime qualifiers compatibly includes the other
   /// if the lifetime qualifiers match, or if both are non-__weak and the
   /// including set also contains the 'const' qualifier, or both are non-__weak
void print(raw_ostream &OS, const PrintingPolicy &Policy,
              bool appendSpaceIfNonEmpty = false) const;
 
   void Profile(llvm::FoldingSetNodeID &ID) const {
     ID.AddInteger(Mask);
   }
 
 private:
 
-  // bits:     |0 1 2|3 .. 4|5  ..  7|8   ...   31|
-  //           |C R V|GCAttr|Lifetime|AddressSpace|
+  // bits:     |0 1 2|3|4 .. 5|6  ..  8|9   ...   31|
+  //           |C R V|U|GCAttr|Lifetime|AddressSpace|
   uint32_t Mask;
 
-  static const uint32_t GCAttrMask = 0x18;
-  static const uint32_t GCAttrShift = 3;
-  static const uint32_t LifetimeMask = 0xE0;
-  static const uint32_t LifetimeShift = 5;
-  static const uint32_t AddressSpaceMask = ~(CVRMask|GCAttrMask|LifetimeMask);
-  static const uint32_t AddressSpaceShift = 8;
+  static const uint32_t UMask = 0x8;
+  static const uint32_t UShift = 3;
+  static const uint32_t GCAttrMask = 0x30;
+  static const uint32_t GCAttrShift = 4;
+  static const uint32_t LifetimeMask = 0x1C0;
+  static const uint32_t LifetimeShift = 6;
+  static const uint32_t AddressSpaceMask =
+      ~(CVRMask | UMask | GCAttrMask | LifetimeMask);
+  static const uint32_t AddressSpaceShift = 9;
 };
 
 /// A std::pair-like structure for storing a qualified type split
 /// into its local qualifiers and its locally-unqualified type.
 struct SplitQualType {
   /// The locally-unqualified type.
   const Type *Ty;
 
inline bool QualType::isMoreQualifiedThan(QualType other) const {
   return (myQuals != otherQuals && myQuals.compatiblyIncludes(otherQuals));
 }
 
 /// Determine whether this type is at last
 /// as qualified as the Other type. For example, "const volatile
 /// int" is at least as qualified as "const int", "volatile int",
 /// "int", and "const volatile int".
 inline bool QualType::isAtLeastAsQualifiedAs(QualType other) const {
-  return getQualifiers().compatiblyIncludes(other.getQualifiers());
+  Qualifiers otherQuals = other.getQualifiers();
+
+  // Ignore __unaligned qualifier if this type is a void.
+  if (getUnqualifiedType()->isVoidType())
+    otherQuals.removeUnaligned();
+
+  return getQualifiers().compatiblyIncludes(otherQuals);
 }
 
 /// If Type is a reference type (e.g., const
 /// int&), returns the type that the reference refers to ("const
 /// int"). Otherwise, returns the type itself. This routine is used
 /// throughout Sema to implement C++ 5p6:
 ///
 ///   If an expression initially has the type "reference to T" (8.3.2,
 ///   8.5.3), the type is adjusted to "T" prior to any further

include/clang/Basic/AddressSpaces.h

 
 namespace LangAS {
 
 /// \brief Defines the set of possible language-specific address spaces.
 ///
 /// This uses a high starting offset so as not to conflict with any address
 /// space used by a target.
 enum ID {
-  Offset = 0xFFFF00,
+  Offset = 0x7FFF00,
 
   opencl_global = Offset,
   opencl_local,
   opencl_constant,
   opencl_generic,
 
   cuda_device,
   cuda_constant,

include/clang/Basic/Attr.td

def InitSeg : Attr {
   let Documentation = [InitSegDocs];
   let AdditionalMembers = [{
   void printPrettyPragma(raw_ostream &OS, const PrintingPolicy &Policy) const {
     OS << '(' << getSection() << ')';
   }
   }];
 }
 
-def Unaligned : IgnoredAttr {
-  let Spellings = [Keyword<"__unaligned">];
-}
-
 def LoopHint : Attr {
   /// #pragma clang loop <option> directive
   /// vectorize: vectorizes loop operations if State == Enable.
   /// vectorize_width: vectorize loop operations with width 'Value'.
   /// interleave: interleave multiple loop iterations if State == Enable.
   /// interleave_count: interleaves 'Value' loop interations.
   /// unroll: fully unroll loop if State == Enable.
   /// unroll_count: unrolls loop 'Value' times.

include/clang/Basic/DiagnosticSemaKinds.td

def note_ovl_candidate_bad_cvr : Note<"candidate "
     "constructor (the implicit move constructor)|"
     "function (the implicit copy assignment operator)|"
     "function (the implicit move assignment operator)|"
     "constructor (inherited)}0%1 not viable: "
     "%ordinal4 argument (%2) would lose "
     "%select{const|restrict|const and restrict|volatile|const and volatile|"
     "volatile and restrict|const, volatile, and restrict}3 qualifier"
     "%select{||s||s|s|s}3">;
+def note_ovl_candidate_bad_unaligned : Note<"candidate "
+    "%select{function|function|constructor|"
+    "function |function |constructor |"
+    "constructor (the implicit default constructor)|"
+    "constructor (the implicit copy constructor)|"
+    "constructor (the implicit move constructor)|"
+    "function (the implicit copy assignment operator)|"
+    "function (the implicit move assignment operator)|"
+    "constructor (inherited)}0%1 not viable: "
+    "%ordinal4 argument (%2) would lose __unaligned qualifier">;
 def note_ovl_candidate_bad_base_to_derived_conv : Note<"candidate "
     "%select{function|function|constructor|"
     "function |function |constructor |"
     "constructor (the implicit default constructor)|"
     "constructor (the implicit copy constructor)|"
     "constructor (the implicit move constructor)|"
     "function (the implicit copy assignment operator)|"
     "function (the implicit move assignment operator)|"

include/clang/Sema/DeclSpec.h

#include "clang/Basic/OpenCLImageTypes.def"
   // type-qualifiers
   enum TQ {   // NOTE: These flags must be kept in sync with Qualifiers::TQ.
     TQ_unspecified = 0,
     TQ_const       = 1,
     TQ_restrict    = 2,
     TQ_volatile    = 4,
     // This has no corresponding Qualifiers::TQ value, because it's not treated
     // as a qualifier in our type system.
-    TQ_atomic      = 8
+    TQ_atomic      = 8,
+    // There is no corresponding Qualifiers::TQ value, but it's kept separately
+    // in a dedicated Qualifiers::Mask bit.
+    TQ_unaligned   = 16
   };
 
   /// ParsedSpecifiers - Flags to query which specifiers were applied.  This is
   /// returned by getParsedSpecifiers.
   enum ParsedSpecifiers {
     PQ_None                  = 0,
     PQ_StorageClassSpecifier = 1,
     PQ_TypeSpecifier         = 2,
private:
   /*TST*/unsigned TypeSpecType : 6;
   unsigned TypeAltiVecVector : 1;
   unsigned TypeAltiVecPixel : 1;
   unsigned TypeAltiVecBool : 1;
   unsigned TypeSpecOwned : 1;
   unsigned TypeSpecPipe : 1;
 
   // type-qualifiers
-  unsigned TypeQualifiers : 4;  // Bitwise OR of TQ.
+  unsigned TypeQualifiers : 5;  // Bitwise OR of TQ.
 
   // function-specifier
   unsigned FS_inline_specified : 1;
   unsigned FS_forceinline_specified: 1;
   unsigned FS_virtual_specified : 1;
   unsigned FS_explicit_specified : 1;
   unsigned FS_noreturn_specified : 1;
 
private:
   SourceLocation StorageClassSpecLoc, ThreadStorageClassSpecLoc;
   SourceLocation TSWLoc, TSCLoc, TSSLoc, TSTLoc, AltiVecLoc;
   /// TSTNameLoc - If TypeSpecType is any of class, enum, struct, union,
   /// typename, then this is the location of the named type (if present);
   /// otherwise, it is the same as TSTLoc. Hence, the pair TSTLoc and
   /// TSTNameLoc provides source range info for tag types.
   SourceLocation TSTNameLoc;
   SourceRange TypeofParensRange;
-  SourceLocation TQ_constLoc, TQ_restrictLoc, TQ_volatileLoc, TQ_atomicLoc;
+  SourceLocation TQ_constLoc, TQ_restrictLoc, TQ_volatileLoc, TQ_atomicLoc,
+      TQ_unalignedLoc;
   SourceLocation FS_inlineLoc, FS_virtualLoc, FS_explicitLoc, FS_noreturnLoc;
   SourceLocation FS_forceinlineLoc;
   SourceLocation FriendLoc, ModulePrivateLoc, ConstexprLoc, ConceptLoc;
   SourceLocation TQ_pipeLoc;
 
   WrittenBuiltinSpecs writtenBS;
   void SaveWrittenBuiltinSpecs();
 
public:
   // type-qualifiers
 
   /// getTypeQualifiers - Return a set of TQs.
   unsigned getTypeQualifiers() const { return TypeQualifiers; }
   SourceLocation getConstSpecLoc() const { return TQ_constLoc; }
   SourceLocation getRestrictSpecLoc() const { return TQ_restrictLoc; }
   SourceLocation getVolatileSpecLoc() const { return TQ_volatileLoc; }
   SourceLocation getAtomicSpecLoc() const { return TQ_atomicLoc; }
+  SourceLocation getUnalignedSpecLoc() const { return TQ_unalignedLoc; }
   SourceLocation getPipeLoc() const { return TQ_pipeLoc; }
 
   /// \brief Clear out all of the type qualifiers.
   void ClearTypeQualifiers() {
     TypeQualifiers = 0;
     TQ_constLoc = SourceLocation();
     TQ_restrictLoc = SourceLocation();
     TQ_volatileLoc = SourceLocation();
     TQ_atomicLoc = SourceLocation();
+    TQ_unalignedLoc = SourceLocation();
     TQ_pipeLoc = SourceLocation();
   }
 
   // function-specifier
   bool isInlineSpecified() const {
     return FS_inline_specified | FS_forceinline_specified;
   }
   SourceLocation getInlineSpecLoc() const {
SourceRange getSourceRange() const {
     return SourceRange(Loc, EndLoc);
   }
 
   struct TypeInfoCommon {
     AttributeList *AttrList;
   };
 
   struct PointerTypeInfo : TypeInfoCommon {
-    /// The type qualifiers: const/volatile/restrict/atomic.
-    unsigned TypeQuals : 4;
+    /// The type qualifiers: const/volatile/restrict/atomic/unaligned.
+    unsigned TypeQuals : 5;
 
     /// The location of the const-qualifier, if any.
     unsigned ConstQualLoc;
 
     /// The location of the volatile-qualifier, if any.
     unsigned VolatileQualLoc;
 
     /// The location of the restrict-qualifier, if any.
     unsigned RestrictQualLoc;
 
     /// The location of the _Atomic-qualifier, if any.
     unsigned AtomicQualLoc;
 
+    /// The location of the __unaligned-qualifier, if any.
+    unsigned UnalignedQualLoc;
+
     void destroy() {
     }
   };
 
   struct ReferenceTypeInfo : TypeInfoCommon {
     /// The type qualifier: restrict. [GNU] C++ extension
     bool HasRestrict : 1;
     /// True if this is an lvalue reference, false if it's an rvalue reference.
AttributeList *&getAttrListRef() {
     return Common.AttrList;
   }
 
   /// \brief Return a DeclaratorChunk for a pointer.
   static DeclaratorChunk getPointer(unsigned TypeQuals, SourceLocation Loc,
                                     SourceLocation ConstQualLoc,
                                     SourceLocation VolatileQualLoc,
                                     SourceLocation RestrictQualLoc,
-                                    SourceLocation AtomicQualLoc) {
+                                    SourceLocation AtomicQualLoc,
+                                    SourceLocation UnalignedQualLoc) {
     DeclaratorChunk I;
     I.Kind                = Pointer;
     I.Loc                 = Loc;
     I.Ptr.TypeQuals       = TypeQuals;
     I.Ptr.ConstQualLoc    = ConstQualLoc.getRawEncoding();
     I.Ptr.VolatileQualLoc = VolatileQualLoc.getRawEncoding();
     I.Ptr.RestrictQualLoc = RestrictQualLoc.getRawEncoding();
     I.Ptr.AtomicQualLoc   = AtomicQualLoc.getRawEncoding();
+    I.Ptr.UnalignedQualLoc = UnalignedQualLoc.getRawEncoding();
     I.Ptr.AttrList        = nullptr;
     return I;
   }
 
   /// \brief Return a DeclaratorChunk for a reference.
   static DeclaratorChunk getReference(unsigned TypeQuals, SourceLocation Loc,
                                       bool lvalue) {
     DeclaratorChunk I;

include/clang/Sema/Sema.h

bool diagnoseQualifiedDeclaration(CXXScopeSpec &SS, DeclContext *DC,
                                     DeclarationName Name,
                                     SourceLocation Loc);
   void
   diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
                             SourceLocation FallbackLoc,
                             SourceLocation ConstQualLoc = SourceLocation(),
                             SourceLocation VolatileQualLoc = SourceLocation(),
                             SourceLocation RestrictQualLoc = SourceLocation(),
-                            SourceLocation AtomicQualLoc = SourceLocation());
+                            SourceLocation AtomicQualLoc = SourceLocation(),
+                            SourceLocation UnalignedQualLoc = SourceLocation());
 
   static bool adjustContextForLocalExternDecl(DeclContext *&DC);
   void DiagnoseFunctionSpecifiers(const DeclSpec &DS);
   void CheckShadow(Scope *S, VarDecl *D, const LookupResult& R);
   void CheckShadow(Scope *S, VarDecl *D);
 
   /// Warn if 'E', which is an expression that is about to be modified, refers
   /// to a shadowing declaration.

lib/AST/MicrosoftMangle.cpp

void MicrosoftCXXNameMangler::manglePointerExtQualifiers(Qualifiers Quals,
                                                          QualType PointeeType) {
   bool HasRestrict = Quals.hasRestrict();
   if (PointersAre64Bit &&
       (PointeeType.isNull() || !PointeeType->isFunctionType()))
     Out << 'E';
 
   if (HasRestrict)
     Out << 'I';
+
+  if (!PointeeType.isNull() && PointeeType.getLocalQualifiers().hasUnaligned())
+    Out << 'F';
 }
 
 void MicrosoftCXXNameMangler::manglePointerCVQualifiers(Qualifiers Quals) {
   // <pointer-cv-qualifiers> ::= P  # no qualifiers
   //                         ::= Q  # const
   //                         ::= R  # volatile
   //                         ::= S  # const volatile
   bool HasConst = Quals.hasConst(),
case QMM_Mangle:
     break;
   case QMM_Escape:
     if (!IsPointer && Quals) {
       Out << "$$C";
       mangleQualifiers(Quals, false);
     }
     break;
   case QMM_Result:
+    // Presence of __unaligned qualifier shouldn't affect mangling here.
+    Quals.removeUnaligned();
     if ((!IsPointer && Quals) || isa<TagType>(T)) {
       Out << '?';
       mangleQualifiers(Quals, false);
     }
     break;
   }
 
   const Type *ty = T.getTypePtr();

lib/AST/TypePrinter.cpp

void Qualifiers::print(raw_ostream &OS, const PrintingPolicy& Policy,
                        bool appendSpaceIfNonEmpty) const {
   bool addSpace = false;
 
   unsigned quals = getCVRQualifiers();
   if (quals) {
     AppendTypeQualList(OS, quals, Policy.LangOpts.C99);
     addSpace = true;
   }
+  if (hasUnaligned()) {
+    if (addSpace)
+      OS << ' ';
+    OS << "__unaligned";
+    addSpace = true;
+  }
   if (unsigned addrspace = getAddressSpace()) {
     if (addSpace)
       OS << ' ';
     addSpace = true;
     switch (addrspace) {
       case LangAS::opencl_global:
         OS << "__global";
         break;

lib/Parse/ParseDecl.cpp

while (true) {
     case tok::kw___fastcall:
     case tok::kw___stdcall:
     case tok::kw___thiscall:
     case tok::kw___cdecl:
     case tok::kw___vectorcall:
     case tok::kw___ptr64:
     case tok::kw___w64:
     case tok::kw___ptr32:
-    case tok::kw___unaligned:
     case tok::kw___sptr:
     case tok::kw___uptr: {
       IdentifierInfo *AttrName = Tok.getIdentifierInfo();
       SourceLocation AttrNameLoc = ConsumeToken();
       attrs.addNew(AttrName, AttrNameLoc, nullptr, AttrNameLoc, nullptr, 0,
                    AttributeList::AS_Keyword);
       break;
     }
case tok::kw___forceinline: {
       isInvalid = DS.setFunctionSpecForceInline(Loc, PrevSpec, DiagID);
       IdentifierInfo *AttrName = Tok.getIdentifierInfo();
       SourceLocation AttrNameLoc = Tok.getLocation();
       DS.getAttributes().addNew(AttrName, AttrNameLoc, nullptr, AttrNameLoc,
                                 nullptr, 0, AttributeList::AS_Keyword);
       break;
     }
 
+    case tok::kw___unaligned:
+      isInvalid = DS.SetTypeQual(DeclSpec::TQ_unaligned, Loc, PrevSpec, DiagID,
+                                 getLangOpts());
+      break;
+
     case tok::kw___sptr:
     case tok::kw___uptr:
     case tok::kw___ptr64:
     case tok::kw___ptr32:
     case tok::kw___w64:
     case tok::kw___cdecl:
     case tok::kw___stdcall:
     case tok::kw___fastcall:
     case tok::kw___thiscall:
     case tok::kw___vectorcall:
-    case tok::kw___unaligned:
       ParseMicrosoftTypeAttributes(DS.getAttributes());
       continue;
 
     // Borland single token adornments.
     case tok::kw___pascal:
       ParseBorlandTypeAttributes(DS.getAttributes());
       continue;
 
while (1) {
     case tok::kw___constant:
     case tok::kw___generic:
     case tok::kw___read_only:
     case tok::kw___write_only:
     case tok::kw___read_write:
       ParseOpenCLQualifiers(DS.getAttributes());
       break;
 
+    case tok::kw___unaligned:
+      isInvalid = DS.SetTypeQual(DeclSpec::TQ_unaligned, Loc, PrevSpec, DiagID,
+                                 getLangOpts());
+      break;
     case tok::kw___uptr:
       // GNU libc headers in C mode use '__uptr' as an identifer which conflicts
       // with the MS modifier keyword.
       if ((AttrReqs & AR_DeclspecAttributesParsed) && !getLangOpts().CPlusPlus &&
           IdentifierRequired && DS.isEmpty() && NextToken().is(tok::semi)) {
         if (TryKeywordIdentFallback(false))
           continue;
       }
     case tok::kw___sptr:
     case tok::kw___w64:
     case tok::kw___ptr64:
     case tok::kw___ptr32:
     case tok::kw___cdecl:
     case tok::kw___stdcall:
     case tok::kw___fastcall:
     case tok::kw___thiscall:
     case tok::kw___vectorcall:
-    case tok::kw___unaligned:
       if (AttrReqs & AR_DeclspecAttributesParsed) {
         ParseMicrosoftTypeAttributes(DS.getAttributes());
         continue;
       }
       goto DoneWithTypeQuals;
     case tok::kw___pascal:
       if (AttrReqs & AR_VendorAttributesParsed) {
         ParseBorlandTypeAttributes(DS.getAttributes());
if (Kind == tok::star || Kind == tok::caret) {
     // Recursively parse the declarator.
     ParseDeclaratorInternal(D, DirectDeclParser);
     if (Kind == tok::star)
       // Remember that we parsed a pointer type, and remember the type-quals.
       D.AddTypeInfo(DeclaratorChunk::getPointer(DS.getTypeQualifiers(), Loc,
                                                 DS.getConstSpecLoc(),
                                                 DS.getVolatileSpecLoc(),
                                                 DS.getRestrictSpecLoc(),
-                                                DS.getAtomicSpecLoc()),
+                                                DS.getAtomicSpecLoc(),
+                                                DS.getUnalignedSpecLoc()),
                     DS.getAttributes(),
                     SourceLocation());
     else
       // Remember that we parsed a Block type, and remember the type-quals.
       D.AddTypeInfo(DeclaratorChunk::getBlockPointer(DS.getTypeQualifiers(),
                                                      Loc),
                     DS.getAttributes(),
                     SourceLocation());

lib/Parse/ParseTentative.cpp

if (mayBeAbstract &&
       if (TPR != TPResult::Ambiguous)
         return TPR;
     } else {
       // '(' declarator ')'
       // '(' attributes declarator ')'
       // '(' abstract-declarator ')'
       if (Tok.isOneOf(tok::kw___attribute, tok::kw___declspec, tok::kw___cdecl,
                       tok::kw___stdcall, tok::kw___fastcall, tok::kw___thiscall,
-                      tok::kw___vectorcall, tok::kw___unaligned))
+                      tok::kw___vectorcall))
         return TPResult::True; // attributes indicate declaration
       TPResult TPR = TryParseDeclarator(mayBeAbstract, mayHaveIdentifier);
       if (TPR != TPResult::Ambiguous)
         return TPR;
       if (Tok.isNot(tok::r_paren))
         return TPResult::False;
       ConsumeParen();
     }

lib/Sema/DeclSpec.cpp

 
 const char *DeclSpec::getSpecifierName(TQ T) {
   switch (T) {
   case DeclSpec::TQ_unspecified: return "unspecified";
   case DeclSpec::TQ_const:       return "const";
   case DeclSpec::TQ_restrict:    return "restrict";
   case DeclSpec::TQ_volatile:    return "volatile";
   case DeclSpec::TQ_atomic:      return "_Atomic";
+  case DeclSpec::TQ_unaligned:   return "__unaligned";
   }
   llvm_unreachable("Unknown typespec!");
 }
 
 bool DeclSpec::SetStorageClassSpec(Sema &S, SCS SC, SourceLocation Loc,
                                    const char *&PrevSpec,
                                    unsigned &DiagID,
                                    const PrintingPolicy &Policy) {
bool DeclSpec::SetTypeQual(TQ T, SourceLocation Loc, const char *&PrevSpec,
   TypeQualifiers |= T;
 
   switch (T) {
   case TQ_unspecified: break;
   case TQ_const:    TQ_constLoc = Loc; return false;
   case TQ_restrict: TQ_restrictLoc = Loc; return false;
   case TQ_volatile: TQ_volatileLoc = Loc; return false;
   case TQ_atomic:   TQ_atomicLoc = Loc; return false;
+  case TQ_unaligned: TQ_unalignedLoc = Loc; return false;
   }
 
   llvm_unreachable("Unknown type qualifier!");
 }
 
 bool DeclSpec::setFunctionSpecInline(SourceLocation Loc, const char *&PrevSpec,
                                      unsigned &DiagID) {
   // 'inline inline' is ok.  However, since this is likely not what the user
void DeclSpec::Finish(Sema &S, const PrintingPolicy &Policy) {
 
   // If decltype(auto) is used, no other type specifiers are permitted.
   if (TypeSpecType == TST_decltype_auto &&
       (TypeSpecWidth != TSW_unspecified ||
        TypeSpecComplex != TSC_unspecified ||
        TypeSpecSign != TSS_unspecified ||
        TypeAltiVecVector || TypeAltiVecPixel || TypeAltiVecBool ||
        TypeQualifiers)) {
-    const unsigned NumLocs = 8;
+    const unsigned NumLocs = 9;
     SourceLocation ExtraLocs[NumLocs] = {
       TSWLoc, TSCLoc, TSSLoc, AltiVecLoc,
-      TQ_constLoc, TQ_restrictLoc, TQ_volatileLoc, TQ_atomicLoc
+      TQ_constLoc, TQ_restrictLoc, TQ_volatileLoc, TQ_atomicLoc, TQ_unalignedLoc
     };
     FixItHint Hints[NumLocs];
     SourceLocation FirstLoc;
     for (unsigned I = 0; I != NumLocs; ++I) {
       if (ExtraLocs[I].isValid()) {
         if (FirstLoc.isInvalid() ||
             S.getSourceManager().isBeforeInTranslationUnit(ExtraLocs[I],
                                                            FirstLoc))

lib/Sema/SemaCodeComplete.cpp

void Sema::CodeCompleteTypeQualifiers(DeclSpec &DS) {
   if (!(DS.getTypeQualifiers() & DeclSpec::TQ_volatile))
     Results.AddResult("volatile");
   if (getLangOpts().C99 &&
       !(DS.getTypeQualifiers() & DeclSpec::TQ_restrict))
     Results.AddResult("restrict");
   if (getLangOpts().C11 &&
       !(DS.getTypeQualifiers() & DeclSpec::TQ_atomic))
     Results.AddResult("_Atomic");
+  if (getLangOpts().MSVCCompat &&
+      !(DS.getTypeQualifiers() & DeclSpec::TQ_unaligned))
+    Results.AddResult("__unaligned");
   Results.ExitScope();
   HandleCodeCompleteResults(this, CodeCompleter, 
                             Results.getCompletionContext(),
                             Results.data(), Results.size());
 }
 
 void Sema::CodeCompleteBracketDeclarator(Scope *S) {
   CodeCompleteExpression(S, QualType(getASTContext().getSizeType()));

lib/Sema/SemaDecl.cpp

Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
   if (DS.getTypeQualifiers()) {
     if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
       Diag(DS.getConstSpecLoc(), DiagID) << "const";
     if (DS.getTypeQualifiers() & DeclSpec::TQ_volatile)
       Diag(DS.getConstSpecLoc(), DiagID) << "volatile";
     // Restrict is covered above.
     if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
       Diag(DS.getAtomicSpecLoc(), DiagID) << "_Atomic";
+    if (DS.getTypeQualifiers() & DeclSpec::TQ_unaligned)
+      Diag(DS.getUnalignedSpecLoc(), DiagID) << "__unaligned";
   }
 
   // Warn about ignored type attributes, for example:
   // __attribute__((aligned)) struct A;
   // Attributes should be placed after tag to apply to type declaration.
   if (!DS.getAttributes().empty()) {
     DeclSpec::TST TypeSpecType = DS.getTypeSpecType();
     if (TypeSpecType == DeclSpec::TST_class ||
if (DS.getTypeQualifiers()) {
              diag::ext_anonymous_struct_union_qualified)
           << Record->isUnion() << "restrict"
           << FixItHint::CreateRemoval(DS.getRestrictSpecLoc());
       if (DS.getTypeQualifiers() & DeclSpec::TQ_atomic)
         Diag(DS.getAtomicSpecLoc(),
              diag::ext_anonymous_struct_union_qualified)
           << Record->isUnion() << "_Atomic"
           << FixItHint::CreateRemoval(DS.getAtomicSpecLoc());
+      if (DS.getTypeQualifiers() & DeclSpec::TQ_unaligned)
+        Diag(DS.getUnalignedSpecLoc(),
+             diag::ext_anonymous_struct_union_qualified)
+          << Record->isUnion() << "__unaligned"
+          << FixItHint::CreateRemoval(DS.getUnalignedSpecLoc());
 
       DS.ClearTypeQualifiers();
     }
 
     // C++ [class.union]p2:
     //   The member-specification of an anonymous union shall only
     //   define non-static data members. [Note: nested types and
     //   functions cannot be declared within an anonymous union. ]

lib/Sema/SemaDeclObjC.cpp

auto resolveTypeReference = [&](TypeOrClassDecl typeDecl, SourceLocation loc)
     // add the '*'.
     if (type->getAs<ObjCInterfaceType>()) {
       SourceLocation starLoc = getLocForEndOfToken(loc);
       ParsedAttributes parsedAttrs(attrFactory);
       D.AddTypeInfo(DeclaratorChunk::getPointer(/*typeQuals=*/0, starLoc,
                                                 SourceLocation(),
                                                 SourceLocation(),
                                                 SourceLocation(),
+                                                SourceLocation(),
                                                 SourceLocation()),
                                                 parsedAttrs,
                                                 starLoc);
 
       // Diagnose the missing '*'.
       Diag(loc, diag::err_objc_type_arg_missing_star)
         << type
         << FixItHint::CreateInsertion(starLoc, " *");

lib/Sema/SemaExpr.cpp

else if (lhq.withoutObjCGCAttr().withoutObjCLifetime()
                                 rhq.withoutObjCGCAttr().withoutObjCLifetime())
              && (lhptee->isVoidType() || rhptee->isVoidType()))
       ; // keep old
 
     // Treat lifetime mismatches as fatal.
     else if (lhq.getObjCLifetime() != rhq.getObjCLifetime())
       ConvTy = Sema::IncompatiblePointerDiscardsQualifiers;
     
-    // For GCC compatibility, other qualifier mismatches are treated
+    // For GCC/MS compatibility, other qualifier mismatches are treated
     // as still compatible in C.
     else ConvTy = Sema::CompatiblePointerDiscardsQualifiers;
   }
 
   // C99 6.5.16.1p1 (constraint 4): If one operand is a pointer to an object or
   // incomplete type and the other is a pointer to a qualified or unqualified
   // version of void...
   if (lhptee->isVoidType()) {

lib/Sema/SemaOverload.cpp

while (Context.UnwrapSimilarPointerTypes(FromType, ToType)) {
     // conversion. Then, if all is well, we unwrap one more level of
     // pointers or pointers-to-members and do it all again
     // until there are no more pointers or pointers-to-members left to
     // unwrap.
     UnwrappedAnyPointer = true;
 
     Qualifiers FromQuals = FromType.getQualifiers();
     Qualifiers ToQuals = ToType.getQualifiers();
-    
+    // Ignore __unaligned qualifier if this type is void.
+    if (ToType.getUnqualifiedType()->isVoidType())
+      FromQuals.removeUnaligned();
+    
     // Objective-C ARC:
     //   Check Objective-C lifetime conversions.
     if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime() &&
         UnwrappedAnyPointer) {
       if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {
         if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))
           ObjCLifetimeConversion = true;
         FromQuals.removeObjCLifetime();
if (T1Quals.getObjCLifetime() != T2Quals.getObjCLifetime() &&
       T1Quals.compatiblyIncludesObjCLifetime(T2Quals)) {
     if (isNonTrivialObjCLifetimeConversion(T2Quals, T1Quals))
       ObjCLifetimeConversion = true;
 
     T1Quals.removeObjCLifetime();
     T2Quals.removeObjCLifetime();    
   }
     
+  // MS compiler ignores __unaligned qualifier for references; do the same.
+  T1Quals.removeUnaligned();
+  T2Quals.removeUnaligned();
+
   if (T1Quals == T2Quals)
     return Ref_Compatible;
   else if (T1Quals.compatiblyIncludes(T2Quals))
     return Ref_Compatible_With_Added_Qualification;
   else
     return Ref_Related;
 }
 
TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
   //          cv2; otherwise, the program is ill-formed.
   if (RefRelationship == Sema::Ref_Related) {
     // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
     // we would be reference-compatible or reference-compatible with
     // added qualification. But that wasn't the case, so the reference
     // initialization fails.
     //
     // Note that we only want to check address spaces and cvr-qualifiers here.
-    // ObjC GC and lifetime qualifiers aren't important.
+    // ObjC GC, lifetime and unaligned qualifiers aren't important.
     Qualifiers T1Quals = T1.getQualifiers();
     Qualifiers T2Quals = T2.getQualifiers();
     T1Quals.removeObjCGCAttr();
     T1Quals.removeObjCLifetime();
     T2Quals.removeObjCGCAttr();
     T2Quals.removeObjCLifetime();
+    // MS compiler ignores __unaligned qualifier for references; do the same.
+    T1Quals.removeUnaligned();
+    T2Quals.removeUnaligned();
     if (!T1Quals.compatiblyIncludes(T2Quals))
       return ICS;
   }
 
   // If at least one of the types is a class type, the types are not
   // related, and we aren't allowed any user conversions, the
   // reference binding fails. This case is important for breaking
   // recursion, since TryImplicitConversion below will attempt to
if (FromQs.getObjCGCAttr() != ToQs.getObjCGCAttr()) {
       << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
       << FromTy
       << FromQs.getObjCGCAttr() << ToQs.getObjCGCAttr()
       << (unsigned) isObjectArgument << I+1;
       MaybeEmitInheritedConstructorNote(S, Fn);
       return;
     }
 
+    if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) {
+      S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned)
+        << (unsigned) FnKind << FnDesc
+        << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
+        << FromTy << FromQs.hasUnaligned() << I+1;
+      MaybeEmitInheritedConstructorNote(S, Fn);
+      return;
+    }
+
     unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
     assert(CVR && "unexpected qualifiers mismatch");
 
     if (isObjectArgument) {
       S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this)
         << (unsigned) FnKind << FnDesc
         << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
         << FromTy << (CVR - 1);

lib/Sema/SemaType.cpp

if (DiagID) {
       Qs.removeRestrict();
     }
   }
 
   return Context.getQualifiedType(T, Qs);
 }
 
 QualType Sema::BuildQualifiedType(QualType T, SourceLocation Loc,
-                                  unsigned CVRA, const DeclSpec *DS) {
+                                  unsigned CVRAU, const DeclSpec *DS) {
   if (T.isNull())
     return QualType();
 
-  // Convert from DeclSpec::TQ to Qualifiers::TQ by just dropping TQ_atomic.
-  unsigned CVR = CVRA & ~DeclSpec::TQ_atomic;
+  // Convert from DeclSpec::TQ to Qualifiers::TQ by just dropping TQ_atomic and
+  // TQ_unaligned;
+  unsigned CVR = CVRAU & ~(DeclSpec::TQ_atomic | DeclSpec::TQ_unaligned);
 
   // C11 6.7.3/5:
   //   If the same qualifier appears more than once in the same
   //   specifier-qualifier-list, either directly or via one or more typedefs,
   //   the behavior is the same as if it appeared only once.
   //
   // It's not specified what happens when the _Atomic qualifier is applied to
   // a type specified with the _Atomic specifier, but we assume that this
   // should be treated as if the _Atomic qualifier appeared multiple times.
-  if (CVRA & DeclSpec::TQ_atomic && !T->isAtomicType()) {
+  if (CVRAU & DeclSpec::TQ_atomic && !T->isAtomicType()) {
     // C11 6.7.3/5:
     //   If other qualifiers appear along with the _Atomic qualifier in a
     //   specifier-qualifier-list, the resulting type is the so-qualified
     //   atomic type.
     //
     // Don't need to worry about array types here, since _Atomic can't be
     // applied to such types.
     SplitQualType Split = T.getSplitUnqualifiedType();
     T = BuildAtomicType(QualType(Split.Ty, 0),
                         DS ? DS->getAtomicSpecLoc() : Loc);
     if (T.isNull())
       return T;
     Split.Quals.addCVRQualifiers(CVR);
     return BuildQualifiedType(T, Loc, Split.Quals);
   }
 
-  return BuildQualifiedType(T, Loc, Qualifiers::fromCVRMask(CVR), DS);
+  Qualifiers Q = Qualifiers::fromCVRMask(CVR);
+  Q.setUnaligned(CVRAU & DeclSpec::TQ_unaligned);
+  return BuildQualifiedType(T, Loc, Q, DS);
 }
 
 /// \brief Build a paren type including \p T.
 QualType Sema::BuildParenType(QualType T) {
   return Context.getParenType(T);
 }
 
 /// Given that we're building a pointer or reference to the given
done:
   // TODO: mark whether we did this inference?
 }
 
 void Sema::diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
                                      SourceLocation FallbackLoc,
                                      SourceLocation ConstQualLoc,
                                      SourceLocation VolatileQualLoc,
                                      SourceLocation RestrictQualLoc,
-                                     SourceLocation AtomicQualLoc) {
+                                     SourceLocation AtomicQualLoc,
+                                     SourceLocation UnalignedQualLoc) {
   if (!Quals)
     return;
 
   struct Qual {
     const char *Name;
     unsigned Mask;
     SourceLocation Loc;
-  } const QualKinds[4] = {
+  } const QualKinds[5] = {
     { "const", DeclSpec::TQ_const, ConstQualLoc },
     { "volatile", DeclSpec::TQ_volatile, VolatileQualLoc },
     { "restrict", DeclSpec::TQ_restrict, RestrictQualLoc },
-    { "_Atomic", DeclSpec::TQ_atomic, AtomicQualLoc }
+    { "_Atomic", DeclSpec::TQ_atomic, AtomicQualLoc },
+    { "__unaligned", DeclSpec::TQ_unaligned, UnalignedQualLoc }
   };
 
   SmallString<32> QualStr;
   unsigned NumQuals = 0;
   SourceLocation Loc;
-  FixItHint FixIts[4];
+  FixItHint FixIts[5];
 
   // Build a string naming the redundant qualifiers.
-  for (unsigned I = 0; I != 4; ++I) {
+  for (unsigned I = 0; I != 5; ++I) {
     if (Quals & QualKinds[I].Mask) {
       if (!QualStr.empty()) QualStr += ' ';
       QualStr += QualKinds[I].Name;
 
       // If we have a location for the qualifier, offer a fixit.
       SourceLocation QualLoc = QualKinds[I].Loc;
       if (QualLoc.isValid()) {
         FixIts[NumQuals] = FixItHint::CreateRemoval(QualLoc);
         if (Loc.isInvalid() ||
case DeclaratorChunk::Pointer: {
       DeclaratorChunk::PointerTypeInfo &PTI = OuterChunk.Ptr;
       S.diagnoseIgnoredQualifiers(
           diag::warn_qual_return_type,
           PTI.TypeQuals,
           SourceLocation(),
           SourceLocation::getFromRawEncoding(PTI.ConstQualLoc),
           SourceLocation::getFromRawEncoding(PTI.VolatileQualLoc),
           SourceLocation::getFromRawEncoding(PTI.RestrictQualLoc),
-          SourceLocation::getFromRawEncoding(PTI.AtomicQualLoc));
+          SourceLocation::getFromRawEncoding(PTI.AtomicQualLoc),
+          SourceLocation::getFromRawEncoding(PTI.UnalignedQualLoc));
       return;
     }
 
     case DeclaratorChunk::Function:
     case DeclaratorChunk::BlockPointer:
     case DeclaratorChunk::Reference:
     case DeclaratorChunk::Array:
     case DeclaratorChunk::MemberPointer:
static void diagnoseRedundantReturnTypeQualifiers(Sema &S, QualType RetTy,
   // Just parens all the way out to the decl specifiers. Diagnose any qualifiers
   // which are present there.
   S.diagnoseIgnoredQualifiers(diag::warn_qual_return_type,
                               D.getDeclSpec().getTypeQualifiers(),
                               D.getIdentifierLoc(),
                               D.getDeclSpec().getConstSpecLoc(),
                               D.getDeclSpec().getVolatileSpecLoc(),
                               D.getDeclSpec().getRestrictSpecLoc(),
-                              D.getDeclSpec().getAtomicSpecLoc());
+                              D.getDeclSpec().getAtomicSpecLoc(),
+                              D.getDeclSpec().getUnalignedSpecLoc());
 }
 
 static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
                                              TypeSourceInfo *&ReturnTypeInfo) {
   Sema &SemaRef = state.getSema();
   Declarator &D = state.getDeclarator();
   QualType T;
   ReturnTypeInfo = nullptr;

test/CodeGenCXX/mangle-ms-cxx11.cpp

 }
 
 int PR26105() {
   auto add = [](int x) { return ([x](int y) { return x + y; }); };
   return add(3)(4);
 }
 // CHECK-DAG: @"\01??R<lambda_0>@?0??PR26105@@YAHXZ@QBE@H@Z"
 // CHECK-DAG: @"\01??R<lambda_1>@?0???R<lambda_0>@?0??PR26105@@YAHXZ@QBE@H@Z@QBE@H@Z"
+
+int __unaligned * unaligned_foo1() { return 0; }
+int __unaligned * __unaligned * unaligned_foo2() { return 0; }
+__unaligned int unaligned_foo3() { return 0; }
+void unaligned_foo4(int __unaligned *p1) {}
+void unaligned_foo5(int __unaligned * __restrict p1) {}
+template <typename T> T unaligned_foo6(T t) { return t; }
+void unaligned_foo7() { unaligned_foo6<int *>(0); unaligned_foo6<int __unaligned *>(0); }
+
+// CHECK-DAG: @"\01?unaligned_foo1@@YAPFAHXZ"
+// CHECK-DAG: @"\01?unaligned_foo2@@YAPFAPFAHXZ"
+// CHECK-DAG: @"\01?unaligned_foo3@@YAHXZ"
+// CHECK-DAG: @"\01?unaligned_foo4@@YAXPFAH@Z"
+// CHECK-DAG: @"\01?unaligned_foo5@@YAXPIFAH@Z"
+// CHECK-DAG: @"\01??$unaligned_foo6@PAH@@YAPAHPAH@Z"
+// CHECK-DAG: @"\01??$unaligned_foo6@PFAH@@YAPFAHPFAH@Z"

test/CodeGenCXX/mangle-ms-cxx14.cpp

 template <> int WithPMD<nullptr>;
 // CHECK-DAG: "\01??$WithPMD@$GA@A@?0@@3HA"
 
 template <const int *, const int *>
 struct Foo {};
 
 Foo<&x<int>, &x<int>> Zoo;
 // CHECK-DAG: "\01?Zoo@@3U?$Foo@$1??$x@H@@3HA$1?1@3HA@@A"
+
+template <typename T> T unaligned_x;
+extern auto test_unaligned() { return unaligned_x<int __unaligned *>; }
+// CHECK-DAG: "\01??$unaligned_x@PFAH@@3PFAHA"
+

test/Sema/MicrosoftExtensions.c

void myprintf(const char *f, ...) {
   if (1) {
     __va_start(&ap, f);
     vmyprintf(f, ap);
     ap = 0;
   } else {
     __va_start(ap, f); // expected-warning {{incompatible pointer types passing 'my_va_list'}}
   }
 }
+
+// __unaligned handling
+void test_unaligned() {
+  __unaligned int *p1 = 0;
+  int *p2 = p1; // expected-warning {{initializing 'int *' with an expression of type '__unaligned int *' discards qualifiers}}
+  __unaligned int *p3 = p2;
+}
+

test/Sema/address_spaces.c

void foo(_AS3 float *a,
   int _AS1 _AS2 *Y;   // expected-error {{multiple address spaces specified for type}}
   int *_AS1 _AS2 *Z;  // expected-error {{multiple address spaces specified for type}}
 
   _AS1 int local;     // expected-error {{automatic variable qualified with an address space}}
   _AS1 int array[5];  // expected-error {{automatic variable qualified with an address space}}
   _AS1 int arrarr[5][5]; // expected-error {{automatic variable qualified with an address space}}
 
   __attribute__((address_space(-1))) int *_boundsA; // expected-error {{address space is negative}}
-  __attribute__((address_space(0xFFFFFF))) int *_boundsB;
+  __attribute__((address_space(0x7FFFFF))) int *_boundsB;
   __attribute__((address_space(0x1000000))) int *_boundsC; // expected-error {{address space is larger than the maximum supported}}
   // chosen specifically to overflow 32 bits and come out reasonable
   __attribute__((address_space(4294967500))) int *_boundsD; // expected-error {{address space is larger than the maximum supported}}
 
   *a = 5.0f + b;
 }
 
 struct _st {

 }
 
 typedef int PR4997 __attribute__((address_space(Foobar))); // expected-error {{use of undeclared identifier 'Foobar'}}
 __attribute__((address_space("12"))) int *i; // expected-error {{'address_space' attribute requires an integer constant}}
 
 // Clang extension doesn't forbid operations on pointers to different address spaces.
 char* cmp(_AS1 char *x,  _AS2 char *y) {
   return x < y ? x : y; // expected-warning {{pointer type mismatch ('__attribute__((address_space(1))) char *' and '__attribute__((address_space(2))) char *')}}
-}
+}
 

test/Sema/invalid-assignment-constant-address-space.c

 // RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only
 
-#define OPENCL_CONSTANT 16776962
+#define OPENCL_CONSTANT 8388354
 int __attribute__((address_space(OPENCL_CONSTANT))) c[3] = {0};
 
 void foo() {
   c[0] = 1; //expected-error{{read-only variable is not assignable}}
 }

test/SemaCXX/MicrosoftExtensions.cpp

-// RUN: %clang_cc1 %s -triple i686-pc-win32 -fsyntax-only -Wmicrosoft -Wc++11-extensions -Wno-long-long -verify -fms-extensions -fexceptions -fcxx-exceptions
+// RUN: %clang_cc1 %s -triple i686-pc-win32 -fsyntax-only -Wmicrosoft -Wc++11-extensions -Wno-long-long -verify -fms-extensions -fexceptions -fcxx-exceptions -DTEST1
+// RUN: %clang_cc1 %s -triple i686-pc-win32 -fsyntax-only -Wmicrosoft -Wc++11-extensions -Wno-long-long -verify -fexceptions -fcxx-exceptions -DTEST2
 
+#if TEST1
 
 // Microsoft doesn't validate exception specification.
 namespace microsoft_exception_spec {
 
 void foo(); // expected-note {{previous declaration}}
 void foo() throw(); // expected-warning {{exception specification in declaration does not match previous declaration}}
 
 void r6() throw(...); // expected-note {{previous declaration}}

 struct M {
     int __stdcall addP();
     float __stdcall subtractP();
 };
 
 // __unaligned handling
 typedef char __unaligned *aligned_type;
 typedef struct UnalignedTag { int f; } __unaligned *aligned_type2;
+typedef char __unaligned aligned_type3;
 
+// Check that __unaligned qualifier can be used for overloading
+void foo_unaligned(int *arg) {}
+void foo_unaligned(__unaligned int *arg) {}
+void foo_unaligned(int arg) {} // expected-note {{previous definition is here}}
+void foo_unaligned(__unaligned int arg) {} // expected-error {{redefinition of 'foo_unaligned'}}
+class A_unaligned {};
+class B_unaligned : public A_unaligned {};
+int foo_unaligned(__unaligned A_unaligned *arg) { return 0; }
+void *foo_unaligned(B_unaligned *arg) { return 0; }
+
+void test_unaligned() {
+  int *p1 = 0;
+  foo_unaligned(p1);
+
+  __unaligned int *p2 = 0;
+  foo_unaligned(p2);
+
+  __unaligned B_unaligned *p3 = 0;
+  int p4 = foo_unaligned(p3);
+
+  B_unaligned *p5 = p3; // expected-error {{cannot initialize a variable of type 'B_unaligned *' with an lvalue of type '__unaligned B_unaligned *'}}
+
+  __unaligned B_unaligned *p6 = p3;
+}
+
+// Test from PR27367
+// We should accept assignment of an __unaligned pointer to a non-__unaligned
+// pointer to void
+typedef struct _ITEMIDLIST { int i; } ITEMIDLIST;
+typedef ITEMIDLIST __unaligned *LPITEMIDLIST;
+extern "C" __declspec(dllimport) void __stdcall CoTaskMemFree(void* pv);
+__inline void FreeIDListArray(LPITEMIDLIST *ppidls) {
+  CoTaskMemFree(*ppidls);
+  __unaligned int *x = 0;
+  void *y = x;
+}
+
+// Test from PR27666
+// We should accept type conversion of __unaligned to non-__unaligned references
+typedef struct in_addr {
+public:
+  in_addr(in_addr &a) {} // expected-note {{candidate constructor not viable: no known conversion from '__unaligned IN_ADDR *' (aka '__unaligned in_addr *') to 'in_addr &' for 1st argument; dereference the argument with *}}
+  in_addr(in_addr *a) {} // expected-note {{candidate constructor not viable: 1st argument ('__unaligned IN_ADDR *' (aka '__unaligned in_addr *')) would lose __unaligned qualifier}}
+} IN_ADDR;
+
+void f(IN_ADDR __unaligned *a) {
+  IN_ADDR local_addr = *a;
+  IN_ADDR local_addr2 = a; // expected-error {{no viable conversion from '__unaligned IN_ADDR *' (aka '__unaligned in_addr *') to 'IN_ADDR' (aka 'in_addr')}}
+}
 
 template<typename T> void h1(T (__stdcall M::* const )()) { }
 
 void m1() {
   h1<int>(&M::addP);
   h1(&M::subtractP);
 }
 

 
 namespace PR25265 {
 struct S {
   int fn() throw(); // expected-note {{previous declaration is here}}
 };
 
 int S::fn() { return 0; } // expected-warning {{is missing exception specification}}
 }
+
+#elif TEST2
+
+// Check that __unaligned is not recognized if MS extensions are not enabled
+typedef char __unaligned *aligned_type; // expected-error {{expected ';' after top level declarator}}
+
+#else
+
+#error Unknown test mode
+
+#endif
+