1 files changed, 44 insertions, 39 deletions

diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp
index 1644ab4c0725..4ee6c8e71457 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -62,7 +62,7 @@ namespace {
 ///   because LLVM reads from the complete type it can generate incorrect code
 ///   if we do not clip the tail padding off of the bitfield in the complete
 ///   layout.  This introduces a somewhat awkward extra unnecessary clip stage.
-///   The location of the clip is stored internally as a sentinal of type
+///   The location of the clip is stored internally as a sentinel of type
 ///   SCISSOR.  If LLVM were updated to read base types (which it probably
 ///   should because locations of things such as VBases are bogus in the llvm
 ///   type anyway) then we could eliminate the SCISSOR.
@@ -74,7 +74,7 @@ namespace {
 struct CGRecordLowering {
   // MemberInfo is a helper structure that contains information about a record
   // member.  In additional to the standard member types, there exists a
-  // sentinal member type that ensures correct rounding.
+  // sentinel member type that ensures correct rounding.
   struct MemberInfo {
     CharUnits Offset;
     enum InfoKind { VFPtr, VBPtr, Field, Base, VBase, Scissor } Kind;
@@ -95,7 +95,7 @@ struct CGRecordLowering {
   // The constructor.
   CGRecordLowering(CodeGenTypes &Types, const RecordDecl *D, bool Packed);
   // Short helper routines.
-  /// \brief Constructs a MemberInfo instance from an offset and llvm::Type *.
+  /// Constructs a MemberInfo instance from an offset and llvm::Type *.
   MemberInfo StorageInfo(CharUnits Offset, llvm::Type *Data) {
     return MemberInfo(Offset, MemberInfo::Field, Data);
   }
@@ -118,19 +118,19 @@ struct CGRecordLowering {
     return !Context.getTargetInfo().getCXXABI().isMicrosoft();
   }
 
-  /// \brief Wraps llvm::Type::getIntNTy with some implicit arguments.
+  /// Wraps llvm::Type::getIntNTy with some implicit arguments.
   llvm::Type *getIntNType(uint64_t NumBits) {
     return llvm::Type::getIntNTy(Types.getLLVMContext(),
                                  (unsigned)llvm::alignTo(NumBits, 8));
   }
-  /// \brief Gets an llvm type of size NumBytes and alignment 1.
+  /// Gets an llvm type of size NumBytes and alignment 1.
   llvm::Type *getByteArrayType(CharUnits NumBytes) {
     assert(!NumBytes.isZero() && "Empty byte arrays aren't allowed.");
     llvm::Type *Type = llvm::Type::getInt8Ty(Types.getLLVMContext());
     return NumBytes == CharUnits::One() ? Type :
         (llvm::Type *)llvm::ArrayType::get(Type, NumBytes.getQuantity());
   }
-  /// \brief Gets the storage type for a field decl and handles storage
+  /// Gets the storage type for a field decl and handles storage
   /// for itanium bitfields that are smaller than their declared type.
   llvm::Type *getStorageType(const FieldDecl *FD) {
     llvm::Type *Type = Types.ConvertTypeForMem(FD->getType());
@@ -139,7 +139,7 @@ struct CGRecordLowering {
     return getIntNType(std::min(FD->getBitWidthValue(Context),
                              (unsigned)Context.toBits(getSize(Type))));
   }
-  /// \brief Gets the llvm Basesubobject type from a CXXRecordDecl.
+  /// Gets the llvm Basesubobject type from a CXXRecordDecl.
   llvm::Type *getStorageType(const CXXRecordDecl *RD) {
     return Types.getCGRecordLayout(RD).getBaseSubobjectLLVMType();
   }
@@ -168,7 +168,7 @@ struct CGRecordLowering {
   // Layout routines.
   void setBitFieldInfo(const FieldDecl *FD, CharUnits StartOffset, 
                        llvm::Type *StorageType);
-  /// \brief Lowers an ASTRecordLayout to a llvm type.
+  /// Lowers an ASTRecordLayout to a llvm type.
   void lower(bool NonVirtualBaseType);
   void lowerUnion();
   void accumulateFields();
@@ -177,18 +177,18 @@ struct CGRecordLowering {
   void accumulateBases();
   void accumulateVPtrs();
   void accumulateVBases();
-  /// \brief Recursively searches all of the bases to find out if a vbase is
+  /// Recursively searches all of the bases to find out if a vbase is
   /// not the primary vbase of some base class.
   bool hasOwnStorage(const CXXRecordDecl *Decl, const CXXRecordDecl *Query);
   void calculateZeroInit();
-  /// \brief Lowers bitfield storage types to I8 arrays for bitfields with tail
+  /// Lowers bitfield storage types to I8 arrays for bitfields with tail
   /// padding that is or can potentially be used.
   void clipTailPadding();
-  /// \brief Determines if we need a packed llvm struct.
+  /// Determines if we need a packed llvm struct.
   void determinePacked(bool NVBaseType);
-  /// \brief Inserts padding everwhere it's needed.
+  /// Inserts padding everywhere it's needed.
   void insertPadding();
-  /// \brief Fills out the structures that are ultimately consumed.
+  /// Fills out the structures that are ultimately consumed.
   void fillOutputFields();
   // Input memoization fields.
   CodeGenTypes &Types;
@@ -214,12 +214,13 @@ private:
 };
 } // namespace {
 
-CGRecordLowering::CGRecordLowering(CodeGenTypes &Types, const RecordDecl *D,                                 bool Packed)
-  : Types(Types), Context(Types.getContext()), D(D),
-    RD(dyn_cast<CXXRecordDecl>(D)),
-    Layout(Types.getContext().getASTRecordLayout(D)),
-    DataLayout(Types.getDataLayout()), IsZeroInitializable(true),
-    IsZeroInitializableAsBase(true), Packed(Packed) {}
+CGRecordLowering::CGRecordLowering(CodeGenTypes &Types, const RecordDecl *D,
+                                   bool Packed)
+    : Types(Types), Context(Types.getContext()), D(D),
+      RD(dyn_cast<CXXRecordDecl>(D)),
+      Layout(Types.getContext().getASTRecordLayout(D)),
+      DataLayout(Types.getDataLayout()), IsZeroInitializable(true),
+      IsZeroInitializableAsBase(true), Packed(Packed) {}
 
 void CGRecordLowering::setBitFieldInfo(
     const FieldDecl *FD, CharUnits StartOffset, llvm::Type *StorageType) {
@@ -294,8 +295,7 @@ void CGRecordLowering::lowerUnion() {
   // been doing and cause lit tests to change.
   for (const auto *Field : D->fields()) {
     if (Field->isBitField()) {
-      // Skip 0 sized bitfields.
-      if (Field->getBitWidthValue(Context) == 0)
+      if (Field->isZeroLengthBitField(Context))
         continue;
       llvm::Type *FieldType = getStorageType(Field);
       if (LayoutSize < getSize(FieldType))
@@ -380,7 +380,7 @@ CGRecordLowering::accumulateBitFields(RecordDecl::field_iterator Field,
     for (; Field != FieldEnd; ++Field) {
       uint64_t BitOffset = getFieldBitOffset(*Field);
       // Zero-width bitfields end runs.
-      if (Field->getBitWidthValue(Context) == 0) {
+      if (Field->isZeroLengthBitField(Context)) {
         Run = FieldEnd;
         continue;
       }
@@ -404,19 +404,20 @@ CGRecordLowering::accumulateBitFields(RecordDecl::field_iterator Field,
     return;
   }
 
-  // Check if current Field is better as a single field run. When current field
+  // Check if OffsetInRecord is better as a single field run. When OffsetInRecord
   // has legal integer width, and its bitfield offset is naturally aligned, it
   // is better to make the bitfield a separate storage component so as it can be
   // accessed directly with lower cost.
-  auto IsBetterAsSingleFieldRun = [&](RecordDecl::field_iterator Field) {
+  auto IsBetterAsSingleFieldRun = [&](uint64_t OffsetInRecord,
+                                      uint64_t StartBitOffset) {
     if (!Types.getCodeGenOpts().FineGrainedBitfieldAccesses)
       return false;
-    unsigned Width = Field->getBitWidthValue(Context);
-    if (!DataLayout.isLegalInteger(Width))
+    if (!DataLayout.isLegalInteger(OffsetInRecord))
       return false;
-    // Make sure Field is natually aligned if it is treated as an IType integer.
-    if (getFieldBitOffset(*Field) %
-            Context.toBits(getAlignment(getIntNType(Width))) !=
+    // Make sure StartBitOffset is natually aligned if it is treated as an
+    // IType integer.
+     if (StartBitOffset %
+            Context.toBits(getAlignment(getIntNType(OffsetInRecord))) !=
         0)
       return false;
     return true;
@@ -431,26 +432,31 @@ CGRecordLowering::accumulateBitFields(RecordDecl::field_iterator Field,
       if (Field == FieldEnd)
         break;
       // Any non-zero-length bitfield can start a new run.
-      if (Field->getBitWidthValue(Context) != 0) {
+      if (!Field->isZeroLengthBitField(Context)) {
         Run = Field;
         StartBitOffset = getFieldBitOffset(*Field);
         Tail = StartBitOffset + Field->getBitWidthValue(Context);
-        StartFieldAsSingleRun = IsBetterAsSingleFieldRun(Run);
+        StartFieldAsSingleRun = IsBetterAsSingleFieldRun(Tail - StartBitOffset,
+                                                         StartBitOffset); 
       }
       ++Field;
       continue;
     }
 
     // If the start field of a new run is better as a single run, or
-    // if current field is better as a single run, or
-    // if current field has zero width bitfield, or
+    // if current field (or consecutive fields) is better as a single run, or
+    // if current field has zero width bitfield and either
+    // UseZeroLengthBitfieldAlignment or UseBitFieldTypeAlignment is set to
+    // true, or
     // if the offset of current field is inconsistent with the offset of
     // previous field plus its offset,
     // skip the block below and go ahead to emit the storage.
     // Otherwise, try to add bitfields to the run.
     if (!StartFieldAsSingleRun && Field != FieldEnd &&
-        !IsBetterAsSingleFieldRun(Field) &&
-        Field->getBitWidthValue(Context) != 0 &&
+        !IsBetterAsSingleFieldRun(Tail - StartBitOffset, StartBitOffset) &&
+        (!Field->isZeroLengthBitField(Context) ||
+         (!Context.getTargetInfo().useZeroLengthBitfieldAlignment() &&
+          !Context.getTargetInfo().useBitFieldTypeAlignment())) &&
         Tail == getFieldBitOffset(*Field)) {
       Tail += Field->getBitWidthValue(Context);
       ++Field;
@@ -626,7 +632,7 @@ void CGRecordLowering::determinePacked(bool NVBaseType) {
   // non-virtual sub-object and an unpacked complete object or vise versa.
   if (NVSize % NVAlignment)
     Packed = true;
-  // Update the alignment of the sentinal.
+  // Update the alignment of the sentinel.
   if (!Packed)
     Members.back().Data = getIntNType(Context.toBits(Alignment));
 }
@@ -785,8 +791,7 @@ CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D,
   }
                                      
   // Verify that the LLVM and AST field offsets agree.
-  llvm::StructType *ST =
-    dyn_cast<llvm::StructType>(RL->getLLVMType());
+  llvm::StructType *ST = RL->getLLVMType();
   const llvm::StructLayout *SL = getDataLayout().getStructLayout(ST);
 
   const ASTRecordLayout &AST_RL = getContext().getASTRecordLayout(D);
@@ -808,7 +813,7 @@ CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D,
       continue;
 
     // Don't inspect zero-length bitfields.
-    if (FD->getBitWidthValue(getContext()) == 0)
+    if (FD->isZeroLengthBitField(getContext()))
       continue;
 
     const CGBitFieldInfo &Info = RL->getBitFieldInfo(FD);