[MSVC] Implementation of __unaligned as a proper type qualifier

This patch implements __unaligned (MS extension) as a proper type qualifier
(before that, it was implemented as an ignored attribute).

It also fixes PR27367 and PR27666.

Differential Revision: http://reviews.llvm.org/D20103

llvm-svn: 269220

11 files changed, 82 insertions, 24 deletions

diff --git a/clang/lib/AST/MicrosoftMangle.cpp b/clang/lib/AST/MicrosoftMangle.cpp
index c9caddbb6fc..774dab05728 100644
--- a/clang/lib/AST/MicrosoftMangle.cpp
+++ b/clang/lib/AST/MicrosoftMangle.cpp
@@ -1446,6 +1446,9 @@ void MicrosoftCXXNameMangler::manglePointerExtQualifiers(Qualifiers Quals,
 
   if (HasRestrict)
     Out << 'I';
+
+  if (!PointeeType.isNull() && PointeeType.getLocalQualifiers().hasUnaligned())
+    Out << 'F';
 }
 
 void MicrosoftCXXNameMangler::manglePointerCVQualifiers(Qualifiers Quals) {
@@ -1577,6 +1580,8 @@ void MicrosoftCXXNameMangler::mangleType(QualType T, SourceRange Range,
     }
     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);
diff --git a/clang/lib/AST/TypePrinter.cpp b/clang/lib/AST/TypePrinter.cpp
index 0356dc515f4..7e04e81e8d1 100644
--- a/clang/lib/AST/TypePrinter.cpp
+++ b/clang/lib/AST/TypePrinter.cpp
@@ -1593,6 +1593,12 @@ void Qualifiers::print(raw_ostream &OS, const PrintingPolicy& Policy,
     AppendTypeQualList(OS, quals, Policy.LangOpts.C99);
     addSpace = true;
   }
+  if (hasUnaligned()) {
+    if (addSpace)
+      OS << ' ';
+    OS << "__unaligned";
+    addSpace = true;
+  }
   if (unsigned addrspace = getAddressSpace()) {
     if (addSpace)
       OS << ' ';
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 2171e5cfc3d..1c93c08f718 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -609,7 +609,6 @@ void Parser::ParseMicrosoftTypeAttributes(ParsedAttributes &attrs) {
     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();
@@ -3087,6 +3086,11 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
       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:
@@ -3097,7 +3101,6 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
     case tok::kw___fastcall:
     case tok::kw___thiscall:
     case tok::kw___vectorcall:
-    case tok::kw___unaligned:
       ParseMicrosoftTypeAttributes(DS.getAttributes());
       continue;
 
@@ -4798,6 +4801,10 @@ void Parser::ParseTypeQualifierListOpt(DeclSpec &DS, unsigned AttrReqs,
       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.
@@ -4815,7 +4822,6 @@ void Parser::ParseTypeQualifierListOpt(DeclSpec &DS, unsigned AttrReqs,
     case tok::kw___fastcall:
     case tok::kw___thiscall:
     case tok::kw___vectorcall:
-    case tok::kw___unaligned:
       if (AttrReqs & AR_DeclspecAttributesParsed) {
         ParseMicrosoftTypeAttributes(DS.getAttributes());
         continue;
@@ -5038,7 +5044,8 @@ void Parser::ParseDeclaratorInternal(Declarator &D,
                                                 DS.getConstSpecLoc(),
                                                 DS.getVolatileSpecLoc(),
                                                 DS.getRestrictSpecLoc(),
-                                                DS.getAtomicSpecLoc()),
+                                                DS.getAtomicSpecLoc(),
+                                                DS.getUnalignedSpecLoc()),
                     DS.getAttributes(),
                     SourceLocation());
     else
diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
index 4d4bd806f3c..cde558196db 100644
--- a/clang/lib/Parse/ParseTentative.cpp
+++ b/clang/lib/Parse/ParseTentative.cpp
@@ -833,7 +833,7 @@ Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract,
       // '(' 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)
diff --git a/clang/lib/Sema/DeclSpec.cpp b/clang/lib/Sema/DeclSpec.cpp
index ddfe6257cf4..de013afa14d 100644
--- a/clang/lib/Sema/DeclSpec.cpp
+++ b/clang/lib/Sema/DeclSpec.cpp
@@ -494,6 +494,7 @@ const char *DeclSpec::getSpecifierName(TQ T) {
   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!");
 }
@@ -796,6 +797,7 @@ bool DeclSpec::SetTypeQual(TQ T, SourceLocation Loc, const char *&PrevSpec,
   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!");
@@ -961,10 +963,10 @@ void DeclSpec::Finish(Sema &S, const PrintingPolicy &Policy) {
        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;
diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index ab2e718c851..739d70288c5 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -3812,6 +3812,9 @@ void Sema::CodeCompleteTypeQualifiers(DeclSpec &DS) {
   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(),
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 020b474c187..75aca834d2c 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -3985,6 +3985,8 @@ Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
     // 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:
@@ -4242,6 +4244,11 @@ Decl *Sema::BuildAnonymousStructOrUnion(Scope *S, DeclSpec &DS,
              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();
     }
diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index 400dc637754..3fb29d46cf4 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -1503,6 +1503,7 @@ void Sema::actOnObjCTypeArgsOrProtocolQualifiers(
                                                 SourceLocation(),
                                                 SourceLocation(),
                                                 SourceLocation(),
+                                                SourceLocation(),
                                                 SourceLocation()),
                                                 parsedAttrs,
                                                 starLoc);
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index a5ee8bebae7..68fd92fbe1a 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -7140,7 +7140,7 @@ checkPointerTypesForAssignment(Sema &S, QualType LHSType, QualType RHSType) {
     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;
   }
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 481c245bdd8..415eda02ec6 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -2951,6 +2951,10 @@ Sema::IsQualificationConversion(QualType FromType, QualType ToType,
 
     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.
@@ -4159,6 +4163,10 @@ Sema::CompareReferenceRelationship(SourceLocation Loc,
     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))
@@ -4480,13 +4488,16 @@ TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
     // 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;
   }
@@ -9135,6 +9146,15 @@ static void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand,
       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");
 
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 7fd43a87a81..57295fde0b4 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1785,12 +1785,13 @@ QualType Sema::BuildQualifiedType(QualType T, SourceLocation Loc,
 }
 
 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
@@ -1800,7 +1801,7 @@ QualType Sema::BuildQualifiedType(QualType T, SourceLocation Loc,
   // 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
@@ -1817,7 +1818,9 @@ QualType Sema::BuildQualifiedType(QualType T, SourceLocation Loc,
     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.
@@ -2652,7 +2655,8 @@ void Sema::diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
                                      SourceLocation ConstQualLoc,
                                      SourceLocation VolatileQualLoc,
                                      SourceLocation RestrictQualLoc,
-                                     SourceLocation AtomicQualLoc) {
+                                     SourceLocation AtomicQualLoc,
+                                     SourceLocation UnalignedQualLoc) {
   if (!Quals)
     return;
 
@@ -2660,26 +2664,27 @@ void Sema::diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
     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) {
-    if (Quals & QualKinds[I].Mask) {
+  for (auto &E : QualKinds) {
+    if (Quals & E.Mask) {
       if (!QualStr.empty()) QualStr += ' ';
-      QualStr += QualKinds[I].Name;
+      QualStr += E.Name;
 
       // If we have a location for the qualifier, offer a fixit.
-      SourceLocation QualLoc = QualKinds[I].Loc;
+      SourceLocation QualLoc = E.Loc;
       if (QualLoc.isValid()) {
         FixIts[NumQuals] = FixItHint::CreateRemoval(QualLoc);
         if (Loc.isInvalid() ||
@@ -2725,7 +2730,8 @@ static void diagnoseRedundantReturnTypeQualifiers(Sema &S, QualType RetTy,
           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;
     }
 
@@ -2761,7 +2767,8 @@ static void diagnoseRedundantReturnTypeQualifiers(Sema &S, QualType RetTy,
                               D.getDeclSpec().getConstSpecLoc(),
                               D.getDeclSpec().getVolatileSpecLoc(),
                               D.getDeclSpec().getRestrictSpecLoc(),
-                              D.getDeclSpec().getAtomicSpecLoc());
+                              D.getDeclSpec().getAtomicSpecLoc(),
+                              D.getDeclSpec().getUnalignedSpecLoc());
 }
 
 static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,