[JITLink][AArch32] Implement ELF::R_ARM_ABS32 after we stopped skipping debug info sections

We create LinkGraph sections with NoAlloc lifetime now since f05ac80
This means we do process debug info sections now with all their relocations. That's ok for the moment.

Author: weliveindetail

llvm/include/llvm/ExecutionEngine/JITLink/aarch32.h

@@ -27,14 +27,18 @@ namespace aarch32 {
 enum EdgeKind_aarch32 : Edge::Kind {
 
   ///
-  /// Relocations of class Data
+  /// Relocations of class Data respect target endianness (unless otherwise
+  /// specified)
   ///
   FirstDataRelocation = Edge::FirstRelocation,
 
-  /// Plain 32-bit value relocation in target endianness
+  /// Relative 32-bit value relocation
   Data_Delta32 = FirstDataRelocation,
 
-  LastDataRelocation = Data_Delta32,
+  /// Absolute 32-bit value relocation
+  Data_Pointer32,
+
+  LastDataRelocation = Data_Pointer32,
 
   ///
   /// Relocations of class Arm (covers fixed-width 4-byte instruction subset)

llvm/lib/ExecutionEngine/JITLink/ELF_aarch32.cpp

@@ -34,6 +34,8 @@ namespace jitlink {
 /// Translate from ELF relocation type to JITLink-internal edge kind.
 Expected<aarch32::EdgeKind_aarch32> getJITLinkEdgeKind(uint32_t ELFType) {
   switch (ELFType) {
+  case ELF::R_ARM_ABS32:
+    return aarch32::Data_Pointer32;
   case ELF::R_ARM_REL32:
     return aarch32::Data_Delta32;
   case ELF::R_ARM_CALL:
@@ -58,6 +60,8 @@ Expected<uint32_t> getELFRelocationType(Edge::Kind Kind) {
   switch (static_cast<aarch32::EdgeKind_aarch32>(Kind)) {
   case aarch32::Data_Delta32:
     return ELF::R_ARM_REL32;
+  case aarch32::Data_Pointer32:
+    return ELF::R_ARM_ABS32;
   case aarch32::Arm_Call:
     return ELF::R_ARM_CALL;
   case aarch32::Thumb_Call:

llvm/lib/ExecutionEngine/JITLink/aarch32.cpp

@@ -200,6 +200,7 @@ Expected<int64_t> readAddendData(LinkGraph &G, Block &B, const Edge &E) {
 
   switch (Kind) {
   case Data_Delta32:
+  case Data_Pointer32:
     return SignExtend64<32>(support::endian::read32(FixupPtr, Endian));
   default:
     return make_error<JITLinkError>(
@@ -303,6 +304,13 @@ Error applyFixupData(LinkGraph &G, Block &B, const Edge &E) {
     Write32(Value);
     return Error::success();
   }
+  case Data_Pointer32: {
+    int64_t Value = TargetAddress + Addend;
+    if (!isInt<32>(Value))
+      return makeTargetOutOfRangeError(G, B, E);
+    Write32(Value);
+    return Error::success();
+  }
   default:
     return make_error<JITLinkError>(
         "In graph " + G.getName() + ", section " + B.getSection().getName() +