[NFC] Renaming PackStack to AlignPackStack

[Xiangling_L]

Summary

This patch renames PackStack and related variable names to also contain align across Clang. As it is right now, Clang already uses one stack to record the information from both #pragma align and #pragma pack. Leaving it as PackStack is confusing, and could cause people to ignore #pragma align when developing code that interacts with PackStack.

[hubert.reinterpretcast]

clang/lib/Sema/SemaAttr.cpp

65–71

Remove extra space; add missing "the".

365–367

It may be helpful to pre-commit tests with the incorrect behaviour as part of the NFC patch.

385–387

Same comment re: pre-committing tests.

[Xiangling_L]

Add pre-committing tests with the incorrect behaviour as part of the NFC patch.

[hubert.reinterpretcast]

LGTM; thanks.

clang/include/clang/Sema/Sema.h

public:
   /// 1: Insert vtordisps in the presence of vbase overrides and non-trivial
   ///    structors
   /// 2: Always insert vtordisps to support RTTI on partially constructed
   ///    objects
   PragmaStack<MSVtorDispMode> VtorDispStack;
   // #pragma pack.
   // Sentinel to represent when the stack is set to mac68k alignment.
   static const unsigned kMac68kAlignmentSentinel = ~0U;
-  PragmaStack<unsigned> PackStack;
-  // The current #pragma pack values and locations at each #include.
-  struct PackIncludeState {
+  PragmaStack<unsigned> AlignPackStack;
+  // The current #pragma align/pack values and locations at each #include.
+  struct AlignPackIncludeState {
     unsigned CurrentValue;
     SourceLocation CurrentPragmaLocation;
     bool HasNonDefaultValue, ShouldWarnOnInclude;
   };
-  SmallVector<PackIncludeState, 8> PackIncludeStack;
+  SmallVector<AlignPackIncludeState, 8> AlignPackIncludeStack;
   // Segment #pragmas.
   PragmaStack<StringLiteral *> DataSegStack;
   PragmaStack<StringLiteral *> BSSSegStack;
   PragmaStack<StringLiteral *> ConstSegStack;
   PragmaStack<StringLiteral *> CodeSegStack;
 
   // This stack tracks the current state of Sema.CurFPFeatures.
   PragmaStack<FPOptionsOverride> FpPragmaStack;

   /// ActOnPragmaOptionsAlign - Called on well formed \#pragma options align.
   void ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
                                SourceLocation PragmaLoc);
 
   /// ActOnPragmaPack - Called on well formed \#pragma pack(...).
   void ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
                        StringRef SlotLabel, Expr *Alignment);
 
-  enum class PragmaPackDiagnoseKind {
+  enum class PragmaAlignPackDiagnoseKind {
     NonDefaultStateAtInclude,
     ChangedStateAtExit
   };
 
-  void DiagnoseNonDefaultPragmaPack(PragmaPackDiagnoseKind Kind,
+  void DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
                                          SourceLocation IncludeLoc);
-  void DiagnoseUnterminatedPragmaPack();
+  void DiagnoseUnterminatedPragmaAlignPack();
 
   /// ActOnPragmaMSStruct - Called on well formed \#pragma ms_struct [on|off].
   void ActOnPragmaMSStruct(PragmaMSStructKind Kind);
 
   /// ActOnPragmaMSComment - Called on well formed
   /// \#pragma comment(kind, "arg").
   void ActOnPragmaMSComment(SourceLocation CommentLoc, PragmaMSCommentKind Kind,
                             StringRef Arg);

clang/include/clang/Serialization/ASTBitCodes.h

enum ASTRecordTypes {
       /// Record code for types associated with OpenCL extensions.
       OPENCL_EXTENSION_TYPES = 58,
 
       /// Record code for declarations associated with OpenCL extensions.
       OPENCL_EXTENSION_DECLS = 59,
 
       MODULAR_CODEGEN_DECLS = 60,
 
-      /// Record code for \#pragma pack options.
-      PACK_PRAGMA_OPTIONS = 61,
+      /// Record code for \#pragma align/pack options.
+      ALIGN_PACK_PRAGMA_OPTIONS = 61,
 
       /// The stack of open #ifs/#ifdefs recorded in a preamble.
       PP_CONDITIONAL_STACK = 62,
 
       /// A table of skipped ranges within the preprocessing record.
       PPD_SKIPPED_RANGES = 63,
 
       /// Record code for the Decls to be checked for deferred diags.

clang/include/clang/Serialization/ASTReader.h

struct FpPragmaStackEntry {
     FPOptionsOverride Value;
     SourceLocation Location;
     SourceLocation PushLocation;
     StringRef SlotLabel;
   };
   llvm::SmallVector<FpPragmaStackEntry, 2> FpPragmaStack;
   llvm::SmallVector<std::string, 2> FpPragmaStrings;
 
-  /// The pragma pack state.
-  Optional<unsigned> PragmaPackCurrentValue;
-  SourceLocation PragmaPackCurrentLocation;
-  struct PragmaPackStackEntry {
+  /// The pragma align/pack state.
+  Optional<unsigned> PragmaAlignPackCurrentValue;
+  SourceLocation PragmaAlignPackCurrentLocation;
+  struct PragmaAlignPackStackEntry {
     unsigned Value;
     SourceLocation Location;
     SourceLocation PushLocation;
     StringRef SlotLabel;
   };
-  llvm::SmallVector<PragmaPackStackEntry, 2> PragmaPackStack;
-  llvm::SmallVector<std::string, 2> PragmaPackStrings;
+  llvm::SmallVector<PragmaAlignPackStackEntry, 2> PragmaAlignPackStack;
+  llvm::SmallVector<std::string, 2> PragmaAlignPackStrings;
 
   /// The OpenCL extension settings.
   OpenCLOptions OpenCLExtensions;
 
   /// Extensions required by an OpenCL type.
   llvm::DenseMap<const Type *, std::set<std::string>> OpenCLTypeExtMap;
 
   /// Extensions required by an OpenCL declaration.

clang/lib/Sema/Sema.cpp

case EnterFile: {
       if (IncludeLoc.isValid()) {
         if (llvm::timeTraceProfilerEnabled()) {
           const FileEntry *FE = SM.getFileEntryForID(SM.getFileID(Loc));
           llvm::timeTraceProfilerBegin(
               "Source", FE != nullptr ? FE->getName() : StringRef("<unknown>"));
         }
 
         IncludeStack.push_back(IncludeLoc);
-        S->DiagnoseNonDefaultPragmaPack(
-            Sema::PragmaPackDiagnoseKind::NonDefaultStateAtInclude, IncludeLoc);
+        S->DiagnoseNonDefaultPragmaAlignPack(
+            Sema::PragmaAlignPackDiagnoseKind::NonDefaultStateAtInclude,
+            IncludeLoc);
       }
       break;
     }
     case ExitFile:
       if (!IncludeStack.empty()) {
         if (llvm::timeTraceProfilerEnabled())
           llvm::timeTraceProfilerEnd();
 
-        S->DiagnoseNonDefaultPragmaPack(
-            Sema::PragmaPackDiagnoseKind::ChangedStateAtExit,
+        S->DiagnoseNonDefaultPragmaAlignPack(
+            Sema::PragmaAlignPackDiagnoseKind::ChangedStateAtExit,
             IncludeStack.pop_back_val());
       }
       break;
     default:
       break;
     }
   }
 };
Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     : ExternalSource(nullptr), isMultiplexExternalSource(false),
       CurFPFeatures(pp.getLangOpts()), LangOpts(pp.getLangOpts()), PP(pp),
       Context(ctxt), Consumer(consumer), Diags(PP.getDiagnostics()),
       SourceMgr(PP.getSourceManager()), CollectStats(false),
       CodeCompleter(CodeCompleter), CurContext(nullptr),
       OriginalLexicalContext(nullptr), MSStructPragmaOn(false),
       MSPointerToMemberRepresentationMethod(
           LangOpts.getMSPointerToMemberRepresentationMethod()),
-      VtorDispStack(LangOpts.getVtorDispMode()), PackStack(0),
+      VtorDispStack(LangOpts.getVtorDispMode()), AlignPackStack(0),
       DataSegStack(nullptr), BSSSegStack(nullptr), ConstSegStack(nullptr),
       CodeSegStack(nullptr), FpPragmaStack(FPOptionsOverride()),
       CurInitSeg(nullptr), VisContext(nullptr),
       PragmaAttributeCurrentTargetDecl(nullptr),
       IsBuildingRecoveryCallExpr(false), Cleanup{}, LateTemplateParser(nullptr),
       LateTemplateParserCleanup(nullptr), OpaqueParser(nullptr), IdResolver(pp),
       StdExperimentalNamespaceCache(nullptr), StdInitializerList(nullptr),
       StdCoroutineTraitsCache(nullptr), CXXTypeInfoDecl(nullptr),
if (TUKind != TU_Prefix) {
     LateParsedInstantiations.clear();
 
     if (LangOpts.PCHInstantiateTemplates) {
       llvm::TimeTraceScope TimeScope("PerformPendingInstantiations");
       PerformPendingInstantiations();
     }
   }
 
-  DiagnoseUnterminatedPragmaPack();
+  DiagnoseUnterminatedPragmaAlignPack();
   DiagnoseUnterminatedPragmaAttribute();
 
   // All delayed member exception specs should be checked or we end up accepting
   // incompatible declarations.
   assert(DelayedOverridingExceptionSpecChecks.empty());
   assert(DelayedEquivalentExceptionSpecChecks.empty());
 
   // All dllexport classes should have been processed already.

clang/lib/Sema/SemaAttr.cpp

if (ShouldAct) {
     S.BSSSegStack.SentinelAction(PSK_Pop, SlotLabel);
     S.ConstSegStack.SentinelAction(PSK_Pop, SlotLabel);
     S.CodeSegStack.SentinelAction(PSK_Pop, SlotLabel);
   }
 }
 
 void Sema::AddAlignmentAttributesForRecord(RecordDecl *RD) {
   // If there is no pack value, we don't need any attributes.
-  if (!PackStack.CurrentValue)
+  if (!AlignPackStack.CurrentValue)
     return;
 
   // Otherwise, check to see if we need a max field alignment attribute.
-  if (unsigned Alignment = PackStack.CurrentValue) {
+  if (unsigned Alignment = AlignPackStack.CurrentValue) {
     if (Alignment == Sema::kMac68kAlignmentSentinel)
       RD->addAttr(AlignMac68kAttr::CreateImplicit(Context));
     else
       RD->addAttr(MaxFieldAlignmentAttr::CreateImplicit(Context,
                                                         Alignment * 8));
   }
-  if (PackIncludeStack.empty())
+  if (AlignPackIncludeStack.empty())
     return;
-  // The #pragma pack affected a record in an included file,  so Clang should
-  // warn when that pragma was written in a file that included the included
-  // file.
-  for (auto &PackedInclude : llvm::reverse(PackIncludeStack)) {
-    if (PackedInclude.CurrentPragmaLocation != PackStack.CurrentPragmaLocation)
+  // The #pragma align/pack affected a record in an included file, so Clang
+  // should warn when that the pragma was written in a file that included the
+  // included file.
+  for (auto &AlignPackedInclude : llvm::reverse(AlignPackIncludeStack)) {
+    if (AlignPackedInclude.CurrentPragmaLocation !=
+        AlignPackStack.CurrentPragmaLocation)
       break;
-    if (PackedInclude.HasNonDefaultValue)
-      PackedInclude.ShouldWarnOnInclude = true;
+    if (AlignPackedInclude.HasNonDefaultValue)
+      AlignPackedInclude.ShouldWarnOnInclude = true;
   }
 }
 
 void Sema::AddMsStructLayoutForRecord(RecordDecl *RD) {
   if (MSStructPragmaOn)
     RD->addAttr(MSStructAttr::CreateImplicit(Context));
 
   // FIXME: We should merge AddAlignmentAttributesForRecord with
case POAK_Mac68k:
     Action = Sema::PSK_Push_Set;
     Alignment = Sema::kMac68kAlignmentSentinel;
     break;
 
   case POAK_Reset:
     // Reset just pops the top of the stack, or resets the current alignment to
     // default.
     Action = Sema::PSK_Pop;
-    if (PackStack.Stack.empty()) {
-      if (PackStack.CurrentValue) {
+    if (AlignPackStack.Stack.empty()) {
+      if (AlignPackStack.CurrentValue) {
         Action = Sema::PSK_Reset;
       } else {
         Diag(PragmaLoc, diag::warn_pragma_options_align_reset_failed)
             << "stack empty";
         return;
       }
     }
     break;
   }
 
-  PackStack.Act(PragmaLoc, Action, StringRef(), Alignment);
+  AlignPackStack.Act(PragmaLoc, Action, StringRef(), Alignment);
 }
 
 void Sema::ActOnPragmaClangSection(SourceLocation PragmaLoc, PragmaClangSectionAction Action,
                                    PragmaClangSectionKind SecKind, StringRef SecName) {
   PragmaClangSection *CSec;
   int SectionFlags = ASTContext::PSF_Read;
   switch (SecKind) {
     case PragmaClangSectionKind::PCSK_BSS:
if (Alignment) {
     }
 
     AlignmentVal = (unsigned)Val->getZExtValue();
   }
   if (Action == Sema::PSK_Show) {
     // Show the current alignment, making sure to show the right value
     // for the default.
     // FIXME: This should come from the target.
-    AlignmentVal = PackStack.CurrentValue;
+    AlignmentVal = AlignPackStack.CurrentValue;
     if (AlignmentVal == 0)
       AlignmentVal = 8;
     if (AlignmentVal == Sema::kMac68kAlignmentSentinel)
       Diag(PragmaLoc, diag::warn_pragma_pack_show) << "mac68k";
     else
       Diag(PragmaLoc, diag::warn_pragma_pack_show) << AlignmentVal;
   }
   // MSDN, C/C++ Preprocessor Reference > Pragma Directives > pack:
   // "#pragma pack(pop, identifier, n) is undefined"
   if (Action & Sema::PSK_Pop) {
     if (Alignment && !SlotLabel.empty())
       Diag(PragmaLoc, diag::warn_pragma_pack_pop_identifier_and_alignment);
-    if (PackStack.Stack.empty())
+    if (AlignPackStack.Stack.empty())
       Diag(PragmaLoc, diag::warn_pragma_pop_failed) << "pack" << "stack empty";
   }
 
-  PackStack.Act(PragmaLoc, Action, SlotLabel, AlignmentVal);
+  AlignPackStack.Act(PragmaLoc, Action, SlotLabel, AlignmentVal);
 }
 
-void Sema::DiagnoseNonDefaultPragmaPack(PragmaPackDiagnoseKind Kind,
+void Sema::DiagnoseNonDefaultPragmaAlignPack(PragmaAlignPackDiagnoseKind Kind,
                                              SourceLocation IncludeLoc) {
-  if (Kind == PragmaPackDiagnoseKind::NonDefaultStateAtInclude) {
-    SourceLocation PrevLocation = PackStack.CurrentPragmaLocation;
+  if (Kind == PragmaAlignPackDiagnoseKind::NonDefaultStateAtInclude) {
+    SourceLocation PrevLocation = AlignPackStack.CurrentPragmaLocation;
     // Warn about non-default alignment at #includes (without redundant
     // warnings for the same directive in nested includes).
     // The warning is delayed until the end of the file to avoid warnings
     // for files that don't have any records that are affected by the modified
     // alignment.
     bool HasNonDefaultValue =
-        PackStack.hasValue() &&
-        (PackIncludeStack.empty() ||
-         PackIncludeStack.back().CurrentPragmaLocation != PrevLocation);
-    PackIncludeStack.push_back(
-        {PackStack.CurrentValue,
-         PackStack.hasValue() ? PrevLocation : SourceLocation(),
+        AlignPackStack.hasValue() &&
+        (AlignPackIncludeStack.empty() ||
+         AlignPackIncludeStack.back().CurrentPragmaLocation != PrevLocation);
+    AlignPackIncludeStack.push_back(
+        {AlignPackStack.CurrentValue,
+         AlignPackStack.hasValue() ? PrevLocation : SourceLocation(),
          HasNonDefaultValue, /*ShouldWarnOnInclude*/ false});
     return;
   }
 
-  assert(Kind == PragmaPackDiagnoseKind::ChangedStateAtExit && "invalid kind");
-  PackIncludeState PrevPackState = PackIncludeStack.pop_back_val();
-  if (PrevPackState.ShouldWarnOnInclude) {
+  assert(Kind == PragmaAlignPackDiagnoseKind::ChangedStateAtExit &&
+         "invalid kind");
+  AlignPackIncludeState PrevAlignPackState =
+      AlignPackIncludeStack.pop_back_val();
+  // FIXME: AlignPackStack may contain both #pragma align and #pragma pack
+  // information, diagnostics below might not be accurate if we have mixed
+  // pragmas.
+  if (PrevAlignPackState.ShouldWarnOnInclude) {
     // Emit the delayed non-default alignment at #include warning.
     Diag(IncludeLoc, diag::warn_pragma_pack_non_default_at_include);
-    Diag(PrevPackState.CurrentPragmaLocation, diag::note_pragma_pack_here);
+    Diag(PrevAlignPackState.CurrentPragmaLocation, diag::note_pragma_pack_here);
   }
   // Warn about modified alignment after #includes.
-  if (PrevPackState.CurrentValue != PackStack.CurrentValue) {
+  if (PrevAlignPackState.CurrentValue != AlignPackStack.CurrentValue) {
     Diag(IncludeLoc, diag::warn_pragma_pack_modified_after_include);
-    Diag(PackStack.CurrentPragmaLocation, diag::note_pragma_pack_here);
+    Diag(AlignPackStack.CurrentPragmaLocation, diag::note_pragma_pack_here);
   }
 }
 
-void Sema::DiagnoseUnterminatedPragmaPack() {
-  if (PackStack.Stack.empty())
+void Sema::DiagnoseUnterminatedPragmaAlignPack() {
+  if (AlignPackStack.Stack.empty())
     return;
   bool IsInnermost = true;
-  for (const auto &StackSlot : llvm::reverse(PackStack.Stack)) {
+
+  // FIXME: AlignPackStack may contain both #pragma align and #pragma pack
+  // information, diagnostics below might not be accurate if we have mixed
+  // pragmas.
+  for (const auto &StackSlot : llvm::reverse(AlignPackStack.Stack)) {
     Diag(StackSlot.PragmaPushLocation, diag::warn_pragma_pack_no_pop_eof);
     // The user might have already reset the alignment, so suggest replacing
     // the reset with a pop.
-    if (IsInnermost && PackStack.CurrentValue == PackStack.DefaultValue) {
-      auto DB = Diag(PackStack.CurrentPragmaLocation,
+    if (IsInnermost &&
+        AlignPackStack.CurrentValue == AlignPackStack.DefaultValue) {
+      auto DB = Diag(AlignPackStack.CurrentPragmaLocation,
                      diag::note_pragma_pack_pop_instead_reset);
-      SourceLocation FixItLoc = Lexer::findLocationAfterToken(
-          PackStack.CurrentPragmaLocation, tok::l_paren, SourceMgr, LangOpts,
+      SourceLocation FixItLoc =
+          Lexer::findLocationAfterToken(AlignPackStack.CurrentPragmaLocation,
+                                        tok::l_paren, SourceMgr, LangOpts,
                                         /*SkipTrailing=*/false);
       if (FixItLoc.isValid())
         DB << FixItHint::CreateInsertion(FixItLoc, "pop");
     }
     IsInnermost = false;
   }
 }
 
 void Sema::ActOnPragmaMSStruct(PragmaMSStructKind Kind) {

clang/lib/Serialization/ASTReader.cpp

while (true) {
     case CUDA_PRAGMA_FORCE_HOST_DEVICE_DEPTH:
       if (Record.size() != 1) {
         Error("invalid cuda pragma options record");
         return Failure;
       }
       ForceCUDAHostDeviceDepth = Record[0];
       break;
 
-    case PACK_PRAGMA_OPTIONS: {
+    case ALIGN_PACK_PRAGMA_OPTIONS: {
       if (Record.size() < 3) {
         Error("invalid pragma pack record");
         return Failure;
       }
-      PragmaPackCurrentValue = Record[0];
-      PragmaPackCurrentLocation = ReadSourceLocation(F, Record[1]);
+      PragmaAlignPackCurrentValue = Record[0];
+      PragmaAlignPackCurrentLocation = ReadSourceLocation(F, Record[1]);
       unsigned NumStackEntries = Record[2];
       unsigned Idx = 3;
       // Reset the stack when importing a new module.
-      PragmaPackStack.clear();
+      PragmaAlignPackStack.clear();
       for (unsigned I = 0; I < NumStackEntries; ++I) {
-        PragmaPackStackEntry Entry;
+        PragmaAlignPackStackEntry Entry;
         Entry.Value = Record[Idx++];
         Entry.Location = ReadSourceLocation(F, Record[Idx++]);
         Entry.PushLocation = ReadSourceLocation(F, Record[Idx++]);
-        PragmaPackStrings.push_back(ReadString(Record, Idx));
-        Entry.SlotLabel = PragmaPackStrings.back();
-        PragmaPackStack.push_back(Entry);
+        PragmaAlignPackStrings.push_back(ReadString(Record, Idx));
+        Entry.SlotLabel = PragmaAlignPackStrings.back();
+        PragmaAlignPackStack.push_back(Entry);
       }
       break;
     }
 
     case FLOAT_CONTROL_PRAGMA_OPTIONS: {
       if (Record.size() < 3) {
         Error("invalid pragma pack record");
         return Failure;
void ASTReader::UpdateSema() {
   if (PointersToMembersPragmaLocation.isValid()) {
     SemaObj->ActOnPragmaMSPointersToMembers(
         (LangOptions::PragmaMSPointersToMembersKind)
             PragmaMSPointersToMembersState,
         PointersToMembersPragmaLocation);
   }
   SemaObj->ForceCUDAHostDeviceDepth = ForceCUDAHostDeviceDepth;
 
-  if (PragmaPackCurrentValue) {
+  if (PragmaAlignPackCurrentValue) {
     // The bottom of the stack might have a default value. It must be adjusted
     // to the current value to ensure that the packing state is preserved after
     // popping entries that were included/imported from a PCH/module.
     bool DropFirst = false;
-    if (!PragmaPackStack.empty() &&
-        PragmaPackStack.front().Location.isInvalid()) {
-      assert(PragmaPackStack.front().Value == SemaObj->PackStack.DefaultValue &&
+    if (!PragmaAlignPackStack.empty() &&
+        PragmaAlignPackStack.front().Location.isInvalid()) {
+      assert(PragmaAlignPackStack.front().Value ==
+                 SemaObj->AlignPackStack.DefaultValue &&
              "Expected a default alignment value");
-      SemaObj->PackStack.Stack.emplace_back(
-          PragmaPackStack.front().SlotLabel, SemaObj->PackStack.CurrentValue,
-          SemaObj->PackStack.CurrentPragmaLocation,
-          PragmaPackStack.front().PushLocation);
+      SemaObj->AlignPackStack.Stack.emplace_back(
+          PragmaAlignPackStack.front().SlotLabel,
+          SemaObj->AlignPackStack.CurrentValue,
+          SemaObj->AlignPackStack.CurrentPragmaLocation,
+          PragmaAlignPackStack.front().PushLocation);
       DropFirst = true;
     }
     for (const auto &Entry :
-         llvm::makeArrayRef(PragmaPackStack).drop_front(DropFirst ? 1 : 0))
-      SemaObj->PackStack.Stack.emplace_back(Entry.SlotLabel, Entry.Value,
-                                            Entry.Location, Entry.PushLocation);
-    if (PragmaPackCurrentLocation.isInvalid()) {
-      assert(*PragmaPackCurrentValue == SemaObj->PackStack.DefaultValue &&
+         llvm::makeArrayRef(PragmaAlignPackStack).drop_front(DropFirst ? 1 : 0))
+      SemaObj->AlignPackStack.Stack.emplace_back(
+          Entry.SlotLabel, Entry.Value, Entry.Location, Entry.PushLocation);
+    if (PragmaAlignPackCurrentLocation.isInvalid()) {
+      assert(*PragmaAlignPackCurrentValue ==
+                 SemaObj->AlignPackStack.DefaultValue &&
              "Expected a default alignment value");
       // Keep the current values.
     } else {
-      SemaObj->PackStack.CurrentValue = *PragmaPackCurrentValue;
-      SemaObj->PackStack.CurrentPragmaLocation = PragmaPackCurrentLocation;
+      SemaObj->AlignPackStack.CurrentValue = *PragmaAlignPackCurrentValue;
+      SemaObj->AlignPackStack.CurrentPragmaLocation =
+          PragmaAlignPackCurrentLocation;
     }
   }
   if (FpPragmaCurrentValue) {
     // The bottom of the stack might have a default value. It must be adjusted
     // to the current value to ensure that fp-pragma state is preserved after
     // popping entries that were included/imported from a PCH/module.
     bool DropFirst = false;
     if (!FpPragmaStack.empty() && FpPragmaStack.front().Location.isInvalid()) {

clang/lib/Serialization/ASTWriter.cpp

 //module.
 void ASTWriter::WriteMSPointersToMembersPragmaOptions(Sema &SemaRef) {
   RecordData Record;
   Record.push_back(SemaRef.MSPointerToMemberRepresentationMethod);
   AddSourceLocation(SemaRef.ImplicitMSInheritanceAttrLoc, Record);
   Stream.EmitRecord(POINTERS_TO_MEMBERS_PRAGMA_OPTIONS, Record);
 }
 
-/// Write the state of 'pragma pack' at the end of the module.
+/// Write the state of 'pragma align/pack' at the end of the module.
 void ASTWriter::WritePackPragmaOptions(Sema &SemaRef) {
-  // Don't serialize pragma pack state for modules, since it should only take
-  // effect on a per-submodule basis.
+  // Don't serialize pragma align/pack state for modules, since it should only
+  // take effect on a per-submodule basis.
   if (WritingModule)
     return;
 
   RecordData Record;
-  Record.push_back(SemaRef.PackStack.CurrentValue);
-  AddSourceLocation(SemaRef.PackStack.CurrentPragmaLocation, Record);
-  Record.push_back(SemaRef.PackStack.Stack.size());
-  for (const auto &StackEntry : SemaRef.PackStack.Stack) {
+  Record.push_back(SemaRef.AlignPackStack.CurrentValue);
+  AddSourceLocation(SemaRef.AlignPackStack.CurrentPragmaLocation, Record);
+  Record.push_back(SemaRef.AlignPackStack.Stack.size());
+  for (const auto &StackEntry : SemaRef.AlignPackStack.Stack) {
     Record.push_back(StackEntry.Value);
     AddSourceLocation(StackEntry.PragmaLocation, Record);
     AddSourceLocation(StackEntry.PragmaPushLocation, Record);
     AddString(StackEntry.StackSlotLabel, Record);
   }
-  Stream.EmitRecord(PACK_PRAGMA_OPTIONS, Record);
+  Stream.EmitRecord(ALIGN_PACK_PRAGMA_OPTIONS, Record);
 }
 
 /// Write the state of 'pragma float_control' at the end of the module.
 void ASTWriter::WriteFloatControlPragmaOptions(Sema &SemaRef) {
   // Don't serialize pragma float_control state for modules,
   // since it should only take effect on a per-submodule basis.
   if (WritingModule)
     return;

clang/test/Sema/Inputs/pragma-align-pack1.h

+#ifdef ALIGN_SET_HERE
+#pragma align = mac68k
+// expected-note@-1 {{previous '#pragma pack' directive that modifies alignment is here}}
+// expected-warning@-2 {{unterminated '#pragma pack (push, ...)' at end of file}}
+#endif
+
+#ifdef RECORD_ALIGN
+struct S {
+  int x;
+};
+#endif

clang/test/Sema/misleading-pragma-align-pack-diagnostics.c

+// RUN: %clang_cc1 -triple i686-apple-darwin9 -fsyntax-only -Wpragma-pack-suspicious-include -I %S/Inputs -DALIGN_SET_HERE -verify %s
+// RUN: %clang_cc1 -triple i686-apple-darwin9 -fsyntax-only -Wpragma-pack-suspicious-include -I %S/Inputs -DRECORD_ALIGN -verify %s
+
+#ifdef ALIGN_SET_HERE
+#pragma align = natural // expected-warning {{unterminated '#pragma pack (push, ...)' at end of file}}
+// expected-warning@+9 {{the current #pragma pack alignment value is modified in the included file}}
+#endif
+
+#ifdef RECORD_ALIGN
+#pragma align = mac68k
+// expected-note@-1 {{previous '#pragma pack' directive that modifies alignment is here}}
+// expected-warning@+3 {{non-default #pragma pack value changes the alignment of struct or union members in the included file}}
+#endif
+
+#include "pragma-align-pack1.h"
+
+#ifdef RECORD_ALIGN
+#pragma align = reset
+#endif