[PATCH] D44469: [llvm-readobj] - Teach llvm-readobj to dump .note.gnu.property sections.

[George Rimar via Phabricator via llvm-commits]

grimar added subscribers: espindola, ruiu.
grimar added a comment.

> Have these been found in the wild? If not I would probably wait until
> someone wants to use them.
> 
> Cheers,
> Rafael

I know about 2 possible relative use cases we might want to support in LLD in future:

1. We might want to support Intel CET (https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf)

It is a relatively new thing and supported by bfd, but not by gold yet: https://sourceware.org/bugzilla/show_bug.cgi?id=22915
BFD commit: https://sourceware.org/ml/binutils/2017-06/msg00270.html

2. GNU_PROPERTY_STACK_SIZE. ("Linker should select the maximum value

among all input relocatable objects and copy this property to the output. Run-time loader should raise the stack limit to the value specified in this property.")
(https://sourceware.org/bugzilla/show_bug.cgi?id=22914)

Both of these require linker to know about .note.gnu.property. Second because is a part of System V ABI now 
(and so I supposed we might want to support it in LLD anyways or at least to teach llvm-readobj to parse it for now
and error out on .note.gnu.property section, hence this patch).

About using in the wild I found Linux kernel discussion about that feature (NT_GNU_PROPERTY_TYPE_0):
https://lkml.org/lkml/2017/8/9/529
Looks like they plan to use it, though there are no patches yet AFAIK.

George.


https://reviews.llvm.org/D44469