Revert r308441 "Recommit r308327: Add a warning for missing '#pragma pack (pop)' and suspicious uses of '#pragma pack' in included files"

This seems to have broken the sanitizer-x86_64-linux buildbot. Reverting until
it's fixed, especially since this landed just before the 5.0 branch.

> This commit adds a new -Wpragma-pack warning. It warns in the following cases:
>
> - When a translation unit is missing terminating #pragma pack (pop) directives.
> - When entering an included file if the current alignment value as determined
>   by '#pragma pack' directives is different from the default alignment value.
> - When leaving an included file that changed the state of the current alignment
>   value.
>
> rdar://10184173
>
> Differential Revision: https://reviews.llvm.org/D35484

llvm-svn: 308455

2 files changed, 1 insertions, 90 deletions

diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index 40ffa09de1a..6f0db6ce1c6 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -70,49 +70,6 @@ void Sema::ActOnTranslationUnitScope(Scope *S) {
   PushDeclContext(S, Context.getTranslationUnitDecl());
 }
 
-namespace clang {
-namespace sema {
-
-class SemaPPCallbacks : public PPCallbacks {
-  Sema *S = nullptr;
-  llvm::SmallVector<SourceLocation, 8> IncludeStack;
-
-public:
-  void set(Sema &S) { this->S = &S; }
-
-  void reset() { S = nullptr; }
-
-  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
-                           SrcMgr::CharacteristicKind FileType,
-                           FileID PrevFID) override {
-    if (!S)
-      return;
-    switch (Reason) {
-    case EnterFile: {
-      SourceManager &SM = S->getSourceManager();
-      SourceLocation IncludeLoc = SM.getIncludeLoc(SM.getFileID(Loc));
-      if (IncludeLoc.isValid()) {
-        IncludeStack.push_back(IncludeLoc);
-        S->DiagnoseNonDefaultPragmaPack(
-            Sema::PragmaPackDiagnoseKind::NonDefaultStateAtInclude, IncludeLoc);
-      }
-      break;
-    }
-    case ExitFile:
-      if (!IncludeStack.empty())
-        S->DiagnoseNonDefaultPragmaPack(
-            Sema::PragmaPackDiagnoseKind::ChangedStateAtExit,
-            IncludeStack.pop_back_val());
-      break;
-    default:
-      break;
-    }
-  }
-};
-
-} // end namespace sema
-} // end namespace clang
-
 Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
            TranslationUnitKind TUKind, CodeCompleteConsumer *CodeCompleter)
     : ExternalSource(nullptr), isMultiplexExternalSource(false),
@@ -165,12 +122,6 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
 
   // Initilization of data sharing attributes stack for OpenMP
   InitDataSharingAttributesStack();
-
-  std::unique_ptr<sema::SemaPPCallbacks> Callbacks =
-      llvm::make_unique<sema::SemaPPCallbacks>();
-  SemaPPCallbackHandler = Callbacks.get();
-  PP.addPPCallbacks(std::move(Callbacks));
-  SemaPPCallbackHandler->set(*this);
 }
 
 void Sema::addImplicitTypedef(StringRef Name, QualType T) {
@@ -355,10 +306,6 @@ Sema::~Sema() {
   // Destroys data sharing attributes stack for OpenMP
   DestroyDataSharingAttributesStack();
 
-  // Detach from the PP callback handler which outlives Sema since it's owned
-  // by the preprocessor.
-  SemaPPCallbackHandler->reset();
-
   assert(DelayedTypos.empty() && "Uncorrected typos!");
 }
 
@@ -819,7 +766,6 @@ void Sema::ActOnEndOfTranslationUnit() {
     CheckDelayedMemberExceptionSpecs();
   }
 
-  DiagnoseUnterminatedPragmaPack();
   DiagnoseUnterminatedPragmaAttribute();
 
   // All delayed member exception specs should be checked or we end up accepting
diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 7193450220a..8c13ead6445 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -202,40 +202,6 @@ void Sema::ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
   PackStack.Act(PragmaLoc, Action, SlotLabel, AlignmentVal);
 }
 
-void Sema::DiagnoseNonDefaultPragmaPack(PragmaPackDiagnoseKind Kind,
-                                        SourceLocation IncludeLoc) {
-  if (Kind == PragmaPackDiagnoseKind::NonDefaultStateAtInclude) {
-    SourceLocation PrevLocation = PackStack.CurrentPragmaLocation;
-    // Warn about non-default alignment at #includes (without redundant
-    // warnings for the same directive in nested includes).
-    if (PackStack.hasValue() &&
-        (PackIncludeStack.empty() ||
-         PackIncludeStack.back().second != PrevLocation)) {
-      Diag(IncludeLoc, diag::warn_pragma_pack_non_default_at_include);
-      Diag(PrevLocation, diag::note_pragma_pack_here);
-    }
-    PackIncludeStack.push_back(
-        {PackStack.CurrentValue,
-         PackStack.hasValue() ? PrevLocation : SourceLocation()});
-    return;
-  }
-
-  assert(Kind == PragmaPackDiagnoseKind::ChangedStateAtExit && "invalid kind");
-  unsigned PreviousValue = PackIncludeStack.pop_back_val().first;
-  // Warn about modified alignment after #includes.
-  if (PreviousValue != PackStack.CurrentValue) {
-    Diag(IncludeLoc, diag::warn_pragma_pack_modified_after_include);
-    Diag(PackStack.CurrentPragmaLocation, diag::note_pragma_pack_here);
-  }
-}
-
-void Sema::DiagnoseUnterminatedPragmaPack() {
-  if (PackStack.Stack.empty())
-    return;
-  for (const auto &StackSlot : llvm::reverse(PackStack.Stack))
-    Diag(StackSlot.PragmaPushLocation, diag::warn_pragma_pack_no_pop_eof);
-}
-
 void Sema::ActOnPragmaMSStruct(PragmaMSStructKind Kind) { 
   MSStructPragmaOn = (Kind == PMSST_ON);
 }
@@ -283,8 +249,7 @@ void Sema::PragmaStack<ValueType>::Act(SourceLocation PragmaLocation,
     return;
   }
   if (Action & PSK_Push)
-    Stack.emplace_back(StackSlotLabel, CurrentValue, CurrentPragmaLocation,
-                       PragmaLocation);
+    Stack.push_back(Slot(StackSlotLabel, CurrentValue, CurrentPragmaLocation));
   else if (Action & PSK_Pop) {
     if (!StackSlotLabel.empty()) {
       // If we've got a label, try to find it and jump there.