[all-commits] [llvm/llvm-project] 57a371: Remove overzealous verifier check on DW_OP_LLVM_en...

[adrian-prantl via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 57a371d7010802804343d17b85ac5e0d28d0f309
      https://github.com/llvm/llvm-project/commit/57a371d7010802804343d17b85ac5e0d28d0f309
  Author: Adrian Prantl <aprantl at apple.com>
  Date:   2021-02-04 (Thu, 04 Feb 2021)

  Changed paths:
    M llvm/docs/LangRef.rst
    M llvm/lib/IR/DebugInfoMetadata.cpp
    M llvm/test/Verifier/diexpression-valid-entry-value.ll

  Log Message:
  -----------
  Remove overzealous verifier check on DW_OP_LLVM_entry_value and improve the documentation

Based on the comments in the code, the idea is that AsmPrinter is
unable to produce entry value blocks of arbitrary length, such as
DW_OP_entry_value [DW_OP_reg5 DW_OP_lit1 DW_OP_plus]. But the way the
Verifier check is written it also disallows DW_OP_entry_value
[DW_OP_reg5] DW_OP_lit1 DW_OP_plus which seems to overshoot the
target.

Note that this patch does not change any of the safety guards in
LiveDebugValues — there is zero behavior change for clang. It just
allows us to legalize more complex expressions in future patches.

rdar://73907559

Differential Revision: https://reviews.llvm.org/D95990