[LLD] Use Rela on PowerPC too

[comex]

Summary

The spec for ELF on PowerPC:
http://refspecs.linux-foundation.org/elf/elfspec_ppc.pdf
says:
"The PowerPC family uses only the Elf32_Rela relocation entries with explicit addends."

(EM_PPC64 should be covered by Config->Is64 already.)

[ruiu]

Thank you for the patch!

How did you find it? Can you write a test?

[comex]

Sorry for the delay; here's an updated diff with a test. (The test didn't seem to clearly belong in any existing .s file I saw, so I just made a new one.)

[• espindola]

LGTM. Do you have commit access?

ELF/Driver.cpp

static void setConfigs() {
   bool IsX32 = (Kind == ELF32LEKind && Machine == EM_X86_64);
 
   Config->CopyRelocs = (Config->Relocatable || Config->EmitRelocs);
   Config->Is64 = (Kind == ELF64LEKind || Kind == ELF64BEKind);
   Config->IsLE = (Kind == ELF32LEKind || Kind == ELF64LEKind);
   Config->Endianness =
       Config->IsLE ? support::endianness::little : support::endianness::big;
   Config->IsMips64EL = (Kind == ELF64LEKind && Machine == EM_MIPS);
-  Config->IsRela = Config->Is64 || IsX32 || Config->MipsN32Abi;
+  Config->IsRela = Config->Is64 || IsX32 || Config->MipsN32Abi ||
+                   Machine == EM_PPC;
   Config->Pic = Config->Pie || Config->Shared;
   Config->Wordsize = Config->Is64 ? 8 : 4;
 }
 
 // Returns a value of "-format" option.
 static bool getBinaryOption(StringRef S) {
   if (S == "binary")
     return true;

test/ELF/ppc-rela.s

+# REQUIRES: ppc
+# RUN: llvm-mc -filetype=obj -triple=powerpc-unknown-freebsd %s -o %t
+# RUN: ld.lld %t -o %t2 -shared
+# RUN: llvm-readobj -r %t2 | FileCheck %s
+
+.data
+  .long foo
+
+// CHECK:      Section ({{.*}}) .rela.dyn {
+// CHECK-NEXT:   0x1000 R_PPC_ADDR32 foo 0x0
+// CHECK-NEXT: }