Add a warning for missing '#pragma pack (pop)' and suspicious uses

of '#pragma pack' in included files

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


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@308327 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 5 insertions, 2 deletions

diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 50be74f6bf..a384d051d6 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -3384,6 +3384,7 @@ ASTReader::ReadASTBlock(ModuleFile &F, unsigned ClientLoadCapabilities) {
         PragmaPackStackEntry 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);
@@ -7579,13 +7580,14 @@ void ASTReader::UpdateSema() {
              "Expected a default alignment value");
       SemaObj->PackStack.Stack.emplace_back(
           PragmaPackStack.front().SlotLabel, SemaObj->PackStack.CurrentValue,
-          SemaObj->PackStack.CurrentPragmaLocation);
+          SemaObj->PackStack.CurrentPragmaLocation,
+          PragmaPackStack.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.Location, Entry.PushLocation);
     if (PragmaPackCurrentLocation.isInvalid()) {
       assert(*PragmaPackCurrentValue == SemaObj->PackStack.DefaultValue &&
              "Expected a default alignment value");
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index a875e627bd..9a739579b3 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -4295,6 +4295,7 @@ void ASTWriter::WritePackPragmaOptions(Sema &SemaRef) {
   for (const auto &StackEntry : SemaRef.PackStack.Stack) {
     Record.push_back(StackEntry.Value);
     AddSourceLocation(StackEntry.PragmaLocation, Record);
+    AddSourceLocation(StackEntry.PragmaPushLocation, Record);
     AddString(StackEntry.StackSlotLabel, Record);
   }
   Stream.EmitRecord(PACK_PRAGMA_OPTIONS, Record);