[llvm-readobj][MachO] Fix section type printing

[seiya]

Summary

Currently, llvm-readobj mistakenly decodes section type as section attribute.

This patch fixes the bug and affected tests.

[jhenderson]

The change looks fine to me, although I wasn't able to quickly find the list of section types anywhere to check against. Could you provide me some documentation?

Also, are there test cases for each of the different permitted types?

[rupprecht]

In D66075#1625297, @jhenderson wrote:

The change looks fine to me, although I wasn't able to quickly find the list of section types anywhere to check against. Could you provide me some documentation?

This was already committed to LLVM years ago in rL178679 (+echristo, the committer), but mistakenly removed in rL235863 due to being an unused variable, instead of the right fix, which is clearly the Attributes->Types typo fixed here

Still, I can't find a reference for the original list, it would be good to cite one.

Also, are there test cases for each of the different permitted types?

+1, would be nice to have a test in llvm-readobj that enumerates all section types in a yaml2obj case

(otherwise, LGTM)

[echristo]

The list looks about right from what I recall - we should get a link to where they're documented, but the Apple documentation site moves a bit more than I'd like so this might be the best we can do for now.

[seiya]

Thank you for pointing out the related commits, @rupprecht!

In D66075#1625297, @jhenderson wrote:

The change looks fine to me, although I wasn't able to quickly find the list of section types anywhere to check against. Could you provide me some documentation?

A list of section types in mach-o/loader.h (in Apple's binary utilities) or llvm/Binary/Format/MachO.h might be helpful.

Also, are there test cases for each of the different permitted types?

It looks few of them are not used in these tests. I'll add a new testcase.

[seiya]

Add llvm/test/tools/llvm-readobj/macho-sections.test, which exhaustively tests all section types.

[jhenderson]

llvm/test/tools/llvm-readobj/macho-sections.test

51 ↗

(On Diff #214759)

Are all fields required, or can some be omitted? Same goes throughout the YAML.

llvm/tools/llvm-readobj/MachODumper.cpp

218 ↗

(On Diff #214759)

Since they exist, you should refer to the values in SectionType enum in MachO.h.

227–228 ↗

(On Diff #214759)

ModInitFuncPointers and ModTermFuncPointers would make more sense.

234 ↗

(On Diff #214759)

LazyDylibSymbolPointers

[seiya]

• Addressed review comments.
  • Replaced magic numbers with enum MachO::SectionType.
  • Renamed some section types.

[seiya]

llvm/test/tools/llvm-readobj/macho-sections.test

51 ↗

(On Diff #214759)

Yes they are. (I was wondering about that the whole time and I'd like to make some of them optional at some time if possible)

[alexander-shaposhnikov]

LG, thanks!

[jhenderson]

LGTM too.