[PATCH] D110485: Support [[no_unique_address]] for all targets.

[cqwrteur via Phabricator via cfe-commits]

expnkx updated this revision to Diff 375690.
expnkx added a comment.

I cannot find out where to add attribute that starts with msvc::xxxxx.

I am just applying this "potential" patch to the clang upstream. In the future we can just remove TargetItaniumCXXABI attr in the clang table gen file without worrying about too much. So it is a "noop".

So this patch changes nothing but it makes us be convenient to fix it in the future.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110485/new/

https://reviews.llvm.org/D110485

Files:
  clang/lib/AST/RecordLayoutBuilder.cpp


Index: clang/lib/AST/RecordLayoutBuilder.cpp
===================================================================
--- clang/lib/AST/RecordLayoutBuilder.cpp
+++ clang/lib/AST/RecordLayoutBuilder.cpp
@@ -2919,6 +2919,10 @@
     layoutBitField(FD);
     return;
   }
+  auto *FieldClass = FD->getType()->getAsCXXRecordDecl();
+  bool PotentiallyOverlapping = FD->hasAttr<NoUniqueAddressAttr>() && FieldClass;
+  bool IsOverlappingEmptyField =
+      PotentiallyOverlapping && FieldClass->isEmpty();
   LastFieldIsNonZeroWidthBitfield = false;
   ElementInfo Info = getAdjustedElementInfo(FD);
   Alignment = std::max(Alignment, Info.Alignment);
@@ -2926,7 +2930,7 @@
   if (UseExternalLayout)
     FieldOffset =
         Context.toCharUnitsFromBits(External.getExternalFieldOffset(FD));
-  else if (IsUnion)
+  else if (IsUnion || IsOverlappingEmptyField)
     FieldOffset = CharUnits::Zero();
   else
     FieldOffset = Size.alignTo(Info.Alignment);


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