[PATCH] D80059: [ELF] Parse SHT_GNU_verneed and respect versioned undefined symbols in shared objects

[George Rimar via Phabricator via llvm-commits]

grimar added inline comments.


================
Comment at: lld/ELF/InputFiles.cpp:1225
+
+  const uint8_t *verneedBuf = obj.base() + sec->sh_offset;
+  const uint8_t *bufEnd =
----------------
grimar wrote:
> This looks a bit cleaner probably:
> 
> ```
>   ArrayRef<uint8_t> data =
>       CHECK(obj.template getSectionContentsAsArray<uint8_t>(sec), this);
>   const uint8_t *verneedBuf = data.begin();
> ```
> 
> And then you can just inline `bufEnd` as `data.end()` I think. See below.
You've missed this one?
Using of `getSectionContentsAsArray` has benefits:

It would check the sh_offset/sh_size early and might provide a better error message:

```
ELFFile<ELFT>::getSectionContentsAsArray(const Elf_Shdr *Sec) const {
...
  uintX_t Offset = Sec->sh_offset;
  uintX_t Size = Sec->sh_size;

...
  if (std::numeric_limits<uintX_t>::max() - Offset < Size)
    return createError("section " + getSecIndexForError(this, Sec) +
                       " has a sh_offset (0x" + Twine::utohexstr(Offset) +
                       ") + sh_size (0x" + Twine::utohexstr(Size) +
                       ") that cannot be represented");
  if (Offset + Size > Buf.size())
    return createError("section " + getSecIndexForError(this, Sec) +
                       " has a sh_offset (0x" + Twine::utohexstr(Offset) +
                       ") + sh_size (0x" + Twine::utohexstr(Size) +
                       ") that is greater than the file size (0x" +
                       Twine::utohexstr(Buf.size()) + ")");
```

It also hides the calculations done here like `obj.base() + sec->sh_offset` and
`obj.base() + std::min<uint64_t>(sec->sh_offset + sec->sh_size, obj.getBufSize());`,
what is good.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80059/new/

https://reviews.llvm.org/D80059