[Lldb-commits] [PATCH] D55356: Add a method to get the "base" file address of an object file

[Greg Clayton via Phabricator via lldb-commits]

clayborg added a comment.

In D55356#1327242 <https://reviews.llvm.org/D55356#1327242>, @labath wrote:

> In D55356#1327224 <https://reviews.llvm.org/D55356#1327224>, @clayborg wrote:
>
> > In D55356#1327099 <https://reviews.llvm.org/D55356#1327099>, @labath wrote:
> >
> > > Actually, this now causes an lldb-mi test to fail, but it's not clear to me if the problem is in the test, or this patch. This issue happens when lldb-mi is printing the "library loaded" message after a module gets added to a not-yet-running target. It tries to print the load address by first getting the base address and then converting that to a load address.
> > >
> > > Before this patch, that would always fail, because well.. ELF and PECOFF had this function unimplemented, and for MachO the base address was section-relative, and so it wasn't resolved to a load address without the section being loaded. However, with this patch, in the ELF (and presumably PECOFF) case, the load address is not section-relative and so the `GetLoadAddress` function happily returns the address.
> > >
> > > Is this the expected behavior here? (i.e., object_file->GetLoadAddress().GetLoadAddress(target) returning a valid value even though the target is not running)
> >
> >
> > Not unless someone has manually set the section load address in the test?
>
>
> The test is not setting the load address manually. This simply falls out of how `Address::GetLoadAddress`  is implemented:
>
>   addr_t Address::GetLoadAddress(Target *target) const {
>     SectionSP section_sp(GetSection());
>     if (section_sp) {
>       ...
>     } else {
>       // We don't have a section so the offset is the load address
>       return m_offset;
>     }
>   }
>
>
> So, where's the bug here? It's not clear to me how to change `Address::GetLoadAddress` to do something different than what it is doing now.


So this is a bug really. When there is no section, we should specify what the m_offset is using lldb_private::AddressType in maybe a new ivar name "m_offset_type". Then GetBaseAddress() would specify eAddressTypeFile. And the above code would become:

  addr_t Address::GetLoadAddress(Target *target) const {
    SectionSP section_sp(GetSection());
    if (section_sp) {
      ...
    } else if (m_offset_type == eAddressTypeLoad) {
      // We don't have a section so the offset is the load address
      return m_offset;
    }
  }

We just need to be careful and see if we can not make lldb_private::Address get any bigger byte size wise if we can at all avoid it.


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  https://reviews.llvm.org/D55356/new/

https://reviews.llvm.org/D55356