[PATCH] D51612: [DebugInfo] Handle stack slot offsets for spilled sub-registers in LDV

[David Stenberg via Phabricator via llvm-commits]

dstenb created this revision.
dstenb added reviewers: rnk, aprantl, stoklund.
dstenb added a project: debug-info.
Herald added subscribers: llvm-commits, JDevlieghere, nemanjai.

Extend LDV so that stack slot offsets for spilled sub-registers
are added to the emitted debug locations. This is accomplished
by querying InstrInfo::getStackSlotRange().

With this change, LDV will add a DW_OP_plus_uconst operation to
the expression if a sub-register is spilled. Later on, PEI will
add an offset operation for the stack slot, meaning that we will
get expressions of the forms:

- {DW_OP_constu #fp-offset, DW_OP_minus, DW_OP_plus_uconst #subreg-offset}
- {DW_OP_plus_const #fp-offset, DW_OP_minus, DW_OP_plus_uconst #subreg-offset}

The two offset operations should ideally be merged.


Repository:
  rL LLVM

https://reviews.llvm.org/D51612

Files:
  lib/CodeGen/LiveDebugVariables.cpp
  test/CodeGen/PowerPC/live-debug-vars-subreg-offset.ll

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