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This commit modifies the dwarf expression evaluator in how we handle the deref operation for register and implicit locations on the stack. For a typical memory location a deref operation will read the value from memory. For register and implicit locations the deref operation will read the value from the register or its implicit location. In lldb we eagerly read register and implicit values and push them on the stack so the deref operation for these becomes a "no-op" that leaves the value on the stack and updates the tracked location kind. The motivation for this change is to handle `DW_OP_deref*` operations on location descriptions as described by the heterogenious debugging [extensions](https://rocm.docs.amd.com/projects/llvm-project/en/latest/LLVM/llvm/html/AMDGPUDwarfExtensionsForHeterogeneousDebugging.html#a-2-5-4-4-4-register-location-description-operations). Specifically, for register locations it states > These operations obtain a register location. To fetch the contents of > a register, it is necessary to use DW_OP_regval_type, use one of the > DW_OP_breg* register-based addressing operations, or use DW_OP_deref* on > a register location description. My understanding is that this is the intended behavior from dwarf5 as well and is not a change in behavior.