[PATCH] D15043: [ELF/AArch64] Add support for the R_AARCH64_COPY relocation.

[Igor Kudrin via llvm-commits]

ikudrin added inline comments.

================
Comment at: ELF/Target.cpp:917-919
@@ +916,5 @@
+  case R_AARCH64_ABS64:
+  case R_AARCH64_PREL16:
+  case R_AARCH64_PREL32:
+  case R_AARCH64_PREL64:
+  case R_AARCH64_ADR_PREL_LO21:
----------------
ruiu wrote:
> ikudrin wrote:
> > ruiu wrote:
> > > ikudrin wrote:
> > > > ruiu wrote:
> > > > > ikudrin wrote:
> > > > > > ruiu wrote:
> > > > > > > These are GOT-relative relocations. Do you need to create copy relocations for them?
> > > > > > They are in the same table "4-6, Data relocations" and in the same section "4.6.5 Static Data relocations" as R_AARCH64_ABS* in the following spec: http://infocenter.arm.com/help/topic/com.arm.doc.ihi0056b/IHI0056B_aaelf64.pdf.
> > > > > > 
> > > > > > Can you hint me for some other specs?
> > > > > I'm sorry if that's not clear, I pointed out PREL relocations. (I selected these three lines on Phab, but Phab includes plus/minus one lines to the diff in addition to the selection I made on the web UI.)
> > > > Yes, I've commented the same lines, about _PREL* relocs. I have to admit that I haven't found a real sample to check all of them. I filled the list basing mostly on my understanding of specs. I'll really appreciate any hints and samples.
> > > Since they are GOT-relative, all code that uses these relocations should always reference data through GOT, so no need to create copy relocations. Gold doesn't create copy relocations for them too.
> > The spec says that they are position-relative, not GOT-relative. http://infocenter.arm.com/help/topic/com.arm.doc.ihi0056b/IHI0056B_aaelf64.pdf.
> > Am I wrong? Do you have the other spec?
> Hm, I may have misread the spec. But could you take a look at gold? It seems to me that they do not create copy relocations for them.
Gold doesn't produce COPY relocations in that case. It only makes PLT entry if some conditions met. And they have a comment "This is used to fill the GOT absolute address".


http://reviews.llvm.org/D15043