Add bit stride to DICompositeType (#131680)

In Ada, an array can be packed and the elements can take less space than
their natural object size. For example, for this type:

   type Packed_Array is array (4 .. 8) of Boolean;
   pragma pack (Packed_Array);

... each element of the array occupies a single bit, even though the
"natural" size for a Boolean in memory is a byte.

In DWARF, this is represented by putting a DW_AT_bit_stride onto the
array type itself.

This patch adds a bit stride to DICompositeType so that gnat-llvm can
emit DWARF for these sorts of arrays.

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index f127ca8..9e7aea8 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -611,7 +611,7 @@ DICompositeType *DIBuilder::createArrayType(
     PointerUnion<DIExpression *, DIVariable *> DL,
     PointerUnion<DIExpression *, DIVariable *> AS,
     PointerUnion<DIExpression *, DIVariable *> AL,
-    PointerUnion<DIExpression *, DIVariable *> RK) {
+    PointerUnion<DIExpression *, DIVariable *> RK, Metadata *BitStride) {
   auto *R = DICompositeType::get(
       VMContext, dwarf::DW_TAG_array_type, Name, File, LineNumber,
       getNonCompileUnitScope(Scope), Ty, Size, AlignInBits, 0, DINode::FlagZero,
@@ -623,7 +623,8 @@ DICompositeType *DIBuilder::createArrayType(
       isa<DIExpression *>(AL) ? (Metadata *)cast<DIExpression *>(AL)
                               : (Metadata *)cast<DIVariable *>(AL),
       isa<DIExpression *>(RK) ? (Metadata *)cast<DIExpression *>(RK)
-                              : (Metadata *)cast<DIVariable *>(RK));
+                              : (Metadata *)cast<DIVariable *>(RK),
+      nullptr, nullptr, 0, BitStride);
   trackIfUnresolved(R);
   return R;
 }