[cfe-dev] How does works the allocation of a writable/readable segment in ELF?

[Reid Kleckner]

bcc cfe-dev

Your question is compiler backend related, which makes it more appropriate
for llvmdev at cs.uiuc.edu.  The Clang mailing list is more frontend-oriented.

---

I don't fully understand your question, but I'll try to give some general
ELF information.

If the binary is an executable (ET_EXEC), then the kernel will map memory
for each PT_LOAD segment at p_vaddr.

If the binary is a shared object (ET_DYN), then the *loader* (ld.so, not
the kernel) will map the memory somewhere.  Generally, all p_vaddr values
for ET_DYN ELFs are essentially offsets in the file (not true virtual
addresses).  The loader will find a place in memory for the image and map
in the segments with the same relative positioning.


On Thu, Apr 10, 2014 at 1:21 PM, TheMask <lol.themask at gmail.com> wrote:

> What I'm trying to understand here is segment in the ELF file format that's
> the binary file format used in most modern UNIX as output of compilers for
> this platform. And It's still (very highly) compiler's back-end related.
>
>
>
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