[PowerPC][JITLink] Support R_PPC64_GOT_PCREL34 (#68658)

`R_PPC64_GOT_PCREL34` is generated for pwr10+.

Author: Kai Luo

llvm/include/llvm/ExecutionEngine/JITLink/ppc64.h

@@ -51,6 +51,7 @@ enum EdgeKind_ppc64 : Edge::Kind {
   TOCDelta16HI,
   TOCDelta16LO,
   TOCDelta16LODS,
+  RequestGOTAndTransformToDelta34,
   CallBranchDelta,
   // Need to restore r2 after the bl, suggesting the bl is followed by a nop.
   CallBranchDeltaRestoreTOC,
@@ -170,6 +171,10 @@ class TOCTableManager : public TableManager<TOCTableManager<Endianness>> {
       // Create TOC section if TOC relocation, PLT or GOT is used.
       getOrCreateTOCSection(G);
       return false;
+    case RequestGOTAndTransformToDelta34:
+      E.setKind(ppc64::Delta34);
+      E.setTarget(createEntry(G, E.getTarget()));
+      return true;
     default:
       return false;
     }

llvm/lib/ExecutionEngine/JITLink/ELF_ppc64.cpp

@@ -234,6 +234,9 @@ class ELFLinkGraphBuilder_ppc64
     if (ELFReloc == ELF::R_PPC64_TLSLD)
       return make_error<StringError>("Local-dynamic TLS model is not supported",
                                      inconvertibleErrorCode());
+    if (ELFReloc == ELF::R_PPC64_PCREL_OPT)
+      // TODO: Support PCREL optimization, now ignore it.
+      return Error::success();
 
     auto ObjSymbol = Base::Obj.getRelocationSymbol(Rel, Base::SymTabSec);
     if (!ObjSymbol)
@@ -360,6 +363,9 @@ class ELFLinkGraphBuilder_ppc64
     case ELF::R_PPC64_PCREL34:
       Kind = ppc64::Delta34;
       break;
+    case ELF::R_PPC64_GOT_PCREL34:
+      Kind = ppc64::RequestGOTAndTransformToDelta34;
+      break;
     case ELF::R_PPC64_GOT_TLSGD16_HA:
       Kind = ppc64::RequestTLSDescInGOTAndTransformToTOCDelta16HA;
       break;

llvm/lib/ExecutionEngine/JITLink/ppc64.cpp

@@ -120,6 +120,8 @@ const char *getEdgeKindName(Edge::Kind K) {
     return "TOCDelta16LO";
   case TOCDelta16LODS:
     return "TOCDelta16LODS";
+  case RequestGOTAndTransformToDelta34:
+    return "RequestGOTAndTransformToDelta34";
   case CallBranchDelta:
     return "CallBranchDelta";
   case CallBranchDeltaRestoreTOC:

llvm/test/ExecutionEngine/JITLink/ppc64/ELF_ppc64_relocations.s

@@ -8,6 +8,7 @@
 # RUN:              --abs external_addr14_func=0x0880 \
 # RUN:              --abs external_addr16_data=0x6000 \
 # RUN:              --abs external_addr32_data=0x36668840 \
+# RUN:              --abs pcrel_external_var=0x36668860 \
 # RUN:              --check %s %t/elf_reloc.o
 # RUN: llvm-mc --triple=powerpc64-unknown-linux-gnu --filetype=obj -o \
 # RUN:   %t/elf_reloc.o %s
@@ -18,6 +19,7 @@
 # RUN:              --abs external_addr14_func=0x0880 \
 # RUN:              --abs external_addr16_data=0x6000 \
 # RUN:              --abs external_addr32_data=0x36668840 \
+# RUN:              --abs pcrel_external_var=0x36668860 \
 # RUN:              --check %s %t/elf_reloc.o
 
 # jitlink-check: section_addr(elf_reloc.o, $__GOT) + 0x8000 = __TOC__
@@ -240,6 +242,19 @@ reloc_rel16:
   blr
   .size reloc_rel16, .-reloc_rel16
 
+# Check R_PPC64_GOT_PCREL34
+# jitlink-check: (got_addr(elf_reloc.o, pcrel_external_var) - reloc_got_pcrel34)[33:0] = \
+# jitlink-check:   ((((*{4}(reloc_got_pcrel34)) & 0x3ffff) << 16) | ((*{4}(reloc_got_pcrel34 + 4)) & 0xffff))[33:0]
+  .global reloc_got_pcrel34
+  .p2align 4
+  .type reloc_got_pcrel34,@function
+reloc_got_pcrel34:
+  pld 3,pcrel_external_var@got@pcrel(0),1
+.Lpcrel0:
+  .reloc .Lpcrel0-8,R_PPC64_PCREL_OPT,.-(.Lpcrel0-8)
+  blr
+  .size reloc_got_pcrel34,.-reloc_got_pcrel34
+
   .type	.L.str,@object
 	.section	.rodata.str1.1,"aMS",@progbits,1
 .L.str: