[all-commits] [llvm/llvm-project] edf45e: Suppress spurious warnings due to R_RISCV_SET_ULEB128

[Fangrui Song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: edf45e4eddbc5a10cc3db4397b3b7100e8f03dcf
      https://github.com/llvm/llvm-project/commit/edf45e4eddbc5a10cc3db4397b3b7100e8f03dcf
  Author: Fangrui Song <i at maskray.me>
  Date:   2024-08-09 (Fri, 09 Aug 2024)

  Changed paths:
    M llvm/lib/Object/RelocationResolver.cpp
    A llvm/test/tools/llvm-objdump/ELF/RISCV/source-interleave.ll

  Log Message:
  -----------
  Suppress spurious warnings due to R_RISCV_SET_ULEB128

llvm-objdump -S issues unnecessary warnings for RISC-V relocatable files
containing .debug_loclists or .debug_rnglists sections with ULEB128
relocations. This occurred because `DWARFObjInMemory` verifies support for all
relocation types, triggering warnings for unsupported ones.

```
% llvm-objdump -S a.o
...
0000000000000000 <foo>:
warning: failed to compute relocation: R_RISCV_SUB_ULEB128, Invalid data was encountered while parsing the file
warning: failed to compute relocation: R_RISCV_SET_ULEB128, Invalid data was encountered while parsing the file
...
```

This change fixes #101544 by declaring support for the two ULEB128
relocation types, silencing the spurious warnings.

---

In DWARF v5 builds, DW_LLE_offset_pair/DW_RLE_offset_pair might be
generated in .debug_loclists/.debug_rnglists with ULEB128 relocations.
They are only read by llvm-dwarfdump to dump section content and verbose
DW_AT_location/DW_AT_ranges output for relocatable files.

The DebugInfoDWARF user (e.g. DWARFDebugRnglists.cpp) calls
`Data.getULEB128` without checking the ULEB128 relocations, as the
unrelocated value holds meaning (refer to the assembler
implementation https://reviews.llvm.org/D157657). This differs from
`.quad .Lfoo`, which requires relocation reading (e.g.
https://reviews.llvm.org/D74404).

Pull Request: https://github.com/llvm/llvm-project/pull/101607



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