199d3d77dd
As proposed in https://discourse.llvm.org/t/rfc-flang-representation-for-objects-inside-physical-storage/88026, this patch adds a `storage` Value operand and a `storage_offset` Integer attribute for `[hl]fir.declare` operations. The `storage` operand indicates the raw address of the physical storage a variable belongs to. This is the beginning address of the physical storage. The `storage_offset` specifies a byte offset within the physical storage where the variable object starts.