[PATCH] D84952: [DWARFYAML] Refactor emitDebugSections(). NFC.

[Xing GUO via Phabricator via llvm-commits]

Higuoxing added a comment.

The motivation of this change is that some DWARF sections are optional in the DWARF structure.

  struct Data {
    ...
    Optional<std::vector<StringOffsetsTable>> DebugStrOffsets;
    Optional<std::vector<ARange>> DebugAranges;
    ...
  }

When we call the `emitDebugXXX()` function, we have to make sure that `DebugAranges` is not empty.

  Error emitDebugAranges() {
    assert(DebugAranges && "unexpected emitDebugAranges() call")
    ...
  }

One possible solution is to iterate over the non-empty sections via `getNonEmptySectionNames()`.

The benefit of this approach is that when there's an unexpected `emitDebugXXX()` call, there will be a assertion failure and the failure will be noticed.

Another possible solution is to check the section inside the `emitDebugXXX()` function.

  Error emitDebugAranges() {
    if (!DebugAranges)
      return Error::success();
    ...
  }

The benefit of this approach is that we are able to use the `StringSwitch` class (https://llvm.org/doxygen/classllvm_1_1StringSwitch.html) here and in ELFEmitter.cpp (See Adrian's comments https://reviews.llvm.org/D82296#inline-760267).

  Error Err = StringSwitch<Error>(SecName)
    .Case("debug_aranges", DWARFYAML::emitDebugAranges())
    .Case("debug_xxx", DWARFYAML::emitDebugXXX())
    ...
    .Default(createStringError(errc::not_supported, SecName + " is not supported"));

Any thoughts? Thanks!


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D84952