[llvm-commits] [llvm] r170016 - /llvm/trunk/test/CodeGen/PowerPC/tls-ld-obj.ll

[Bill Schmidt]

Fixed under r170237.

On Fri, 2012-12-14 at 13:21 -0600, Bill Schmidt wrote:
> 
> On Wed, 2012-12-12 at 14:07 -0800, Chandler Carruth wrote:
> > On Wed, Dec 12, 2012 at 12:29 PM, Bill Schmidt
> > <wschmidt at linux.vnet.ibm.com> wrote:
> >         Author: wschmidt
> >         Date: Wed Dec 12 14:29:20 2012
> >         New Revision: 170016
> >         
> >         URL: http://llvm.org/viewvc/llvm-project?rev=170016&view=rev
> >         Log:
> >         The ordering of two relocations on the same instruction is
> >         apparently not
> >         predictable when compiled on at least one non-PowerPC host.
> >          Source of
> >         nondeterminism not apparent.  Restrict the test to build on
> >         PowerPC hosts
> >         for now while looking into the issue further.
> > 
> > 
> > Ow, and thanks for finding this!!! Please let folks know if we can
> > help track this down. Non-determinism is scary.
> 
> Finally got some time to look at this.  The problem appears to be with
> this, from ELFObjectWriter.cpp: WriteRelocationFragment():
> 
>   // Sort the relocation entries. Most targets just sort by r_offset,
> but some
>   // (e.g., MIPS) have additional constraints.
>   TargetObjectWriter->sortRelocs(Asm, Relocs);
> 
> This ends up doing a qsort() based on the r_offset field, which IIRC is
> nondeterministic when two entries have the same key.  I guess I'll have
> to override sortRelocs for PPC.
> 
> >  
> >         
> >         Modified:
> >             llvm/trunk/test/CodeGen/PowerPC/tls-ld-obj.ll
> >         
> >         Modified: llvm/trunk/test/CodeGen/PowerPC/tls-ld-obj.ll
> >         URL:
> >         http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/tls-ld-obj.ll?rev=170016&r1=170015&r2=170016&view=diff
> >         ==============================================================================
> >         --- llvm/trunk/test/CodeGen/PowerPC/tls-ld-obj.ll (original)
> >         +++ llvm/trunk/test/CodeGen/PowerPC/tls-ld-obj.ll Wed Dec 12
> >         14:29:20 2012
> >         @@ -4,6 +4,10 @@
> >          ; Test correct relocation generation for thread-local storage
> >         using
> >          ; the local dynamic model.
> >         
> >         +; Relocations 2 and 3 seem to come out in unpredictable order
> >         on some
> >         +; architectures, so restrict this for now.
> >         +; REQUIRES: ppc64-registered-target
> >         +
> >          target datalayout =
> >         "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
> >          target triple = "powerpc64-unknown-linux-gnu"
> >         
> >         @@ -17,9 +21,10 @@
> >            ret i32 %0
> >          }
> >         
> >         -; Verify generation of R_PPC64_GOT_TLSGD16_HA,
> >         R_PPC64_GOT_TLSGD16_LO,
> >         -; and R_PPC64_TLSGD for accessing external variable a, and
> >         R_PPC64_REL24
> >         -; for the call to __tls_get_addr.
> >         +; Verify generation of R_PPC64_GOT_TLSLD16_HA,
> >         R_PPC64_GOT_TLSLD16_LO,
> >         +; R_PPC64_TLSLD, R_PPC64_DTPREL16_HA, and R_PPC64_DTPREL16_LO
> >         for
> >         +; accessing external variable a, and R_PPC64_REL24 for the
> >         call to
> >         +; __tls_get_addr.
> >          ;
> >          ; CHECK:       '.rela.text'
> >          ; CHECK:       Relocation 0
> >         
> >         
> >         _______________________________________________
> >         llvm-commits mailing list
> >         llvm-commits at cs.uiuc.edu
> >         http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> > 
> > 
> 
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