[SOL] re-enable debug info and add R_BPF_64_{ABS64, ABS32, NODYLD32} relocations to lld

Co-Authored-By: Richard Patel <[email protected]>

[SOL] emit R_BPF_64_{ABS64, ABS32} for .debug_* sections

Author: jawilk

lld/ELF/Arch/BPF.cpp

@@ -45,6 +45,9 @@ RelExpr BPF::getRelExpr(RelType type, const Symbol &s,
   switch (type) {
     case R_BPF_64_32:
       return R_PC;
+    case R_BPF_64_ABS32:
+    case R_BPF_64_NODYLD32:
+    case R_BPF_64_ABS64:
     case R_BPF_64_64:
       return R_ABS;
     default:
@@ -68,6 +71,12 @@ void BPF::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
       write32le(loc + 4, ((val - 8) / 8) & 0xFFFFFFFF);
       break;
     }
+    case R_BPF_64_ABS32:
+    case R_BPF_64_NODYLD32: {
+      // Relocation used by .BTF.ext and DWARF
+      write32le(loc, val & 0xFFFFFFFF);
+      break;
+    }
     case R_BPF_64_64: {
       // Relocation of a lddw instruction
       // 64 bit address is divided into the imm of this and the following
@@ -76,6 +85,14 @@ void BPF::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
       write32le(loc + 8 + 4, val >> 32);
       break;
     }
+    case R_BPF_64_ABS64: {
+      // The relocation type is used for normal 64-bit data. The
+      // actual to-be-relocated data is stored at r_offset and the
+      // read/write data bitsize is 64 (8 bytes). The relocation can
+      // be resolved with the symbol value plus implicit addend.
+      write64le(loc, val);
+      break;
+    }
     default:
       error(getErrorLocation(loc) + "unrecognized reloc " + toString(rel.type));
   }

llvm/lib/MC/ELFObjectWriter.cpp

@@ -1455,6 +1455,12 @@ void ELFObjectWriter::recordRelocation(MCAssembler &Asm,
     return;
 
   unsigned Type = TargetObjectWriter->getRelocType(Ctx, Target, Fixup, IsPCRel);
+
+  unsigned Flags = FixupSection.getFlags();
+  // Change R_BPF_64_64 relocations in .debug_* sections to R_BPF_64_ABS64 
+  if (Ctx.getTargetTriple().isBPF() && !(Flags & ELF::SHF_ALLOC) && (Type==ELF::R_BPF_64_64))
+      Type = ELF::R_BPF_64_ABS64;  
+
   const auto *Parent = cast<MCSectionELF>(Fragment->getParent());
   // Emiting relocation with sybmol for CG Profile to  help with --cg-profile.
   bool RelocateWithSymbol =

llvm/lib/Target/BPF/BPFTargetMachine.cpp

@@ -83,8 +83,7 @@ BPFTargetMachine::BPFTargetMachine(const Target &T, const Triple &TT,
   BPFMCAsmInfo *MAI =
       static_cast<BPFMCAsmInfo *>(const_cast<MCAsmInfo *>(AsmInfo.get()));
   MAI->setDwarfUsesRelocationsAcrossSections(!Subtarget.getUseDwarfRIS());
-  bool IsSolana = TT.getArch() == Triple::sbf || FS.contains("solana");
-  MAI->setSupportsDebugInformation(!IsSolana);
+  MAI->setSupportsDebugInformation(true);
 }
 
 namespace {

llvm/lib/Target/BPF/MCTargetDesc/BPFELFObjectWriter.cpp

@@ -92,6 +92,9 @@ unsigned BPFELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
           if ((Flags & ELF::SHF_ALLOC) && (Flags & ELF::SHF_WRITE))
             return ELF::R_BPF_64_NODYLD32;
         }
+        // .debug_* sections
+	if (!(Flags & ELF::SHF_ALLOC))
+       	  return ELF::R_BPF_64_ABS32;
       }
     }
     return isSolana ? ELF::R_BPF_64_32 : ELF::R_BPF_64_ABS32;