[CodeGen] Fix an assertion failure in CGRecordLowering.
This patch fixes a bug in CGRecordLowering::accumulateBitFields where it
unconditionally starts a new run and emits a storage field when it sees
a zero-sized bitfield, which causes an assertion in insertPadding to
fail when -fno-bitfield-type-align is used.
It shouldn't emit new storage if UseZeroLengthBitfieldAlignment and
UseBitFieldTypeAlignment are both false.
rdar://problem/36762205
llvm-svn: 323943
diff --git a/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp b/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
index 1644ab4..d794b12 100644
--- a/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -443,14 +443,18 @@
// 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 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 &&
+ (Field->getBitWidthValue(Context) != 0 ||
+ (!Context.getTargetInfo().useZeroLengthBitfieldAlignment() &&
+ !Context.getTargetInfo().useBitFieldTypeAlignment())) &&
Tail == getFieldBitOffset(*Field)) {
Tail += Field->getBitWidthValue(Context);
++Field;