[DwarfExpression] Support entry values for indirect parameters
Summary:
A struct argument can be passed-by-value to a callee via a pointer to a
temporary stack copy. Add support for emitting an entry value DBG_VALUE
when an indirect parameter DBG_VALUE becomes unavailable. This is done
by omitting DW_OP_stack_value from the entry value expression, to make
the expression describe the location of an object.
rdar://
63373691
Reviewers: djtodoro, aprantl, dstenb
Subscribers: hiraditya, lldb-commits, llvm-commits
Tags: #lldb, #llvm
Differential Revision: https://reviews.llvm.org/D80345