1 files changed, 24 insertions, 15 deletions

diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp
index c754541ac121..4de64a32f2ac 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -1,9 +1,8 @@
 //===--- CGRecordLayoutBuilder.cpp - CGRecordLayout builder  ----*- C++ -*-===//
 //
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
@@ -274,7 +273,7 @@ void CGRecordLowering::lower(bool NVBaseType) {
     if (!NVBaseType)
       accumulateVBases();
   }
-  std::stable_sort(Members.begin(), Members.end());
+  llvm::stable_sort(Members);
   Members.push_back(StorageInfo(Size, getIntNType(8)));
   clipTailPadding();
   determinePacked(NVBaseType);
@@ -348,18 +347,21 @@ void CGRecordLowering::lowerUnion() {
 void CGRecordLowering::accumulateFields() {
   for (RecordDecl::field_iterator Field = D->field_begin(),
                                   FieldEnd = D->field_end();
-    Field != FieldEnd;)
+    Field != FieldEnd;) {
     if (Field->isBitField()) {
       RecordDecl::field_iterator Start = Field;
       // Iterate to gather the list of bitfields.
       for (++Field; Field != FieldEnd && Field->isBitField(); ++Field);
       accumulateBitFields(Start, Field);
-    } else {
+    } else if (!Field->isZeroSize(Context)) {
       Members.push_back(MemberInfo(
           bitsToCharUnits(getFieldBitOffset(*Field)), MemberInfo::Field,
           getStorageType(*Field), *Field));
       ++Field;
+    } else {
+      ++Field;
     }
+  }
 }
 
 void
@@ -591,10 +593,17 @@ void CGRecordLowering::clipTailPadding() {
     if (!Member->Data && Member->Kind != MemberInfo::Scissor)
       continue;
     if (Member->Offset < Tail) {
-      assert(Prior->Kind == MemberInfo::Field && !Prior->FD &&
+      assert(Prior->Kind == MemberInfo::Field &&
              "Only storage fields have tail padding!");
-      Prior->Data = getByteArrayType(bitsToCharUnits(llvm::alignTo(
-          cast<llvm::IntegerType>(Prior->Data)->getIntegerBitWidth(), 8)));
+      if (!Prior->FD || Prior->FD->isBitField())
+        Prior->Data = getByteArrayType(bitsToCharUnits(llvm::alignTo(
+            cast<llvm::IntegerType>(Prior->Data)->getIntegerBitWidth(), 8)));
+      else {
+        assert(Prior->FD->hasAttr<NoUniqueAddressAttr>() &&
+               "should not have reused this field's tail padding");
+        Prior->Data = getByteArrayType(
+            Context.getTypeInfoDataSizeInChars(Prior->FD->getType()).first);
+      }
     }
     if (Member->Data)
       Prior = Member;
@@ -659,7 +668,7 @@ void CGRecordLowering::insertPadding() {
         Pad = Padding.begin(), PadEnd = Padding.end();
         Pad != PadEnd; ++Pad)
     Members.push_back(StorageInfo(Pad->first, getByteArrayType(Pad->second)));
-  std::stable_sort(Members.begin(), Members.end());
+  llvm::stable_sort(Members);
 }
 
 void CGRecordLowering::fillOutputFields() {
@@ -798,6 +807,10 @@ CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D,
   for (unsigned i = 0, e = AST_RL.getFieldCount(); i != e; ++i, ++it) {
     const FieldDecl *FD = *it;
 
+    // Ignore zero-sized fields.
+    if (FD->isZeroSize(getContext()))
+      continue;
+
     // For non-bit-fields, just check that the LLVM struct offset matches the
     // AST offset.
     if (!FD->isBitField()) {
@@ -811,10 +824,6 @@ CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D,
     if (!FD->getDeclName())
       continue;
 
-    // Don't inspect zero-length bitfields.
-    if (FD->isZeroLengthBitField(getContext()))
-      continue;
-
     const CGBitFieldInfo &Info = RL->getBitFieldInfo(FD);
     llvm::Type *ElementTy = ST->getTypeAtIndex(RL->getLLVMFieldNo(FD));