ELF ARM: Produce different relocation type for B and BL (#97823)

dotnet · Feb 2, 2024 · e9539aa · e9539aa
1 parent 36d41c6
commit e9539aa
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diff --git a/src/coreclr/tools/Common/Compiler/DependencyAnalysis/Relocation.cs b/src/coreclr/tools/Common/Compiler/DependencyAnalysis/Relocation.cs
@@ -55,6 +55,7 @@ public enum RelocType
 
  // Linux arm32
  IMAGE_REL_ARM_PREL31 = 0x10D,
+ IMAGE_REL_ARM_JUMP24 = 0x10E,
 
  //
  // Relocations for R2R image production

diff --git a/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/ElfObjectWriter.cs b/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ObjectWriter/ElfObjectWriter.cs
@@ -224,6 +224,16 @@ protected internal override unsafe void EmitRelocation(
  Relocation.WriteValue(relocType, (void*)pData, inlineValue + addend);
  }
  addend = 0;
+
+ // Determine if this is call (BL[X]) or jump (B) since they use different
+ // relocation codes in ELF.
+ // B.W 1111 0Sii iiii iiii 10J1 Jiii iiii iiii
+ // BL 1111 0Sii iiii iiii 11J1 Jiii iiii iiii
+ // BLX 1111 0Sii iiii iiii 11J0 Jiii iiii iii0
+ if (relocType is IMAGE_REL_BASED_THUMB_BRANCH24 && (pData[3] & 0x40) != 0x40)
+ {
+ relocType = IMAGE_REL_ARM_JUMP24;
+ }
  }
  }
 
@@ -378,6 +388,7 @@ private void EmitRelocationsARM(int sectionIndex, List<SymbolicRelocation> reloc
  IMAGE_REL_BASED_THUMB_MOV32 => R_ARM_THM_MOVW_ABS_NC,
  IMAGE_REL_BASED_THUMB_MOV32_PCREL => R_ARM_THM_MOVW_PREL_NC,
  IMAGE_REL_BASED_THUMB_BRANCH24 => R_ARM_THM_CALL,
+ IMAGE_REL_ARM_JUMP24 => R_ARM_THM_JUMP24,
  IMAGE_REL_ARM_PREL31 => R_ARM_PREL31,
  _ => throw new NotSupportedException("Unknown relocation type: " + symbolicRelocation.Type)
  };