Implenment #pack pragma and ms_struct attribute layout.
Concludes // radar://8823265.
llvm-svn: 131188
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index 5a11984..3c397a2 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -1259,6 +1259,7 @@
// the future, this will need to be tweakable by targets.
const FieldDecl *LastFD = 0;
ZeroLengthBitfield = 0;
+ unsigned RemainingInAlignment = 0;
for (RecordDecl::field_iterator Field = D->field_begin(),
FieldEnd = D->field_end(); Field != FieldEnd; ++Field) {
if (IsMsStruct) {
@@ -1295,17 +1296,33 @@
// This check is needed for 'long long' in -m32 mode.
if (TypeSizeLastFD > FieldAlignLastFD)
FieldAlignLastFD = TypeSizeLastFD;
+
if (TypeSizeLastFD != TypeSize) {
+ if (RemainingInAlignment &&
+ LastFD && LastFD->isBitField() &&
+ LastFD->getBitWidth()->EvaluateAsInt(Context).getZExtValue()) {
+ // If previous field was a bitfield with some remaining unfilled
+ // bits, pad the field so current field starts on its type boundary.
+ uint64_t FieldOffset =
+ getDataSizeInBits() - UnfilledBitsInLastByte;
+ uint64_t NewSizeInBits = RemainingInAlignment + FieldOffset;
+ setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
+ Context.Target.getCharAlign()));
+ setSize(std::max(getSizeInBits(), getDataSizeInBits()));
+ RemainingInAlignment = 0;
+ }
+
uint64_t UnpaddedFieldOffset =
getDataSizeInBits() - UnfilledBitsInLastByte;
FieldAlign = std::max(FieldAlign, FieldAlignLastFD);
+
// The maximum field alignment overrides the aligned attribute.
if (!MaxFieldAlignment.isZero()) {
unsigned MaxFieldAlignmentInBits =
Context.toBits(MaxFieldAlignment);
FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
}
-
+
uint64_t NewSizeInBits =
llvm::RoundUpToAlignment(UnpaddedFieldOffset, FieldAlign);
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
@@ -1313,11 +1330,40 @@
UnfilledBitsInLastByte = getDataSizeInBits() - NewSizeInBits;
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
}
+ if (FD->isBitField()) {
+ uint64_t FieldSize =
+ FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
+ assert (FieldSize > 0 && "LayoutFields - ms_struct layout");
+ if (RemainingInAlignment < FieldSize)
+ RemainingInAlignment = TypeSize - FieldSize;
+ else
+ RemainingInAlignment -= FieldSize;
+ }
+ }
+ else if (FD->isBitField()) {
+ uint64_t FieldSize =
+ FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
+ std::pair<uint64_t, unsigned> FieldInfo =
+ Context.getTypeInfo(FD->getType());
+ uint64_t TypeSize = FieldInfo.first;
+ RemainingInAlignment = TypeSize - FieldSize;
}
LastFD = FD;
}
LayoutField(*Field);
}
+ if (IsMsStruct && RemainingInAlignment &&
+ LastFD && LastFD->isBitField() &&
+ LastFD->getBitWidth()->EvaluateAsInt(Context).getZExtValue()) {
+ // If we ended a bitfield before the full length of the type then
+ // pad the struct out to the full length of the last type.
+ uint64_t FieldOffset =
+ getDataSizeInBits() - UnfilledBitsInLastByte;
+ uint64_t NewSizeInBits = RemainingInAlignment + FieldOffset;
+ setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
+ Context.Target.getCharAlign()));
+ setSize(std::max(getSizeInBits(), getDataSizeInBits()));
+ }
}
void RecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,