[JITLink][AArch32] Implement ELF::R_ARM_JUMP24 relocation

Added support and test for ELF::R_ARM_JUMP24

Reviewed By: sgraenitz

Differential Revision: https://reviews.llvm.org/D157541

Author: eymay

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

@@ -52,7 +52,10 @@ enum EdgeKind_aarch32 : Edge::Kind {
   /// Arm and Thumb).
   Arm_Call = FirstArmRelocation,
 
-  LastArmRelocation = Arm_Call,
+  /// Write immediate value for (unconditional) PC-relative branch without link.
+  Arm_Jump24,
+
+  LastArmRelocation = Arm_Jump24,
 
   ///
   /// Relocations of class Thumb16 and Thumb32 (covers Thumb instruction subset)
@@ -149,12 +152,16 @@ struct HalfWords {
 ///
 template <EdgeKind_aarch32 Kind> struct FixupInfo {};
 
-template <> struct FixupInfo<Arm_Call> {
+template <> struct FixupInfo<Arm_Jump24> {
   static constexpr uint32_t Opcode = 0x0a000000;
-  static constexpr uint32_t OpcodeMask = 0x0e000000;
+  static constexpr uint32_t OpcodeMask = 0x0f000000;
   static constexpr uint32_t ImmMask = 0x00ffffff;
   static constexpr uint32_t Unconditional = 0xe0000000;
   static constexpr uint32_t CondMask = 0xe0000000; // excluding BLX bit
+};
+
+template <> struct FixupInfo<Arm_Call> : public FixupInfo<Arm_Jump24> {
+  static constexpr uint32_t OpcodeMask = 0x0e000000;
   static constexpr uint32_t BitH = 0x01000000;
   static constexpr uint32_t BitBlx = 0x10000000;
 };

llvm/lib/ExecutionEngine/JITLink/ELF_aarch32.cpp

@@ -40,6 +40,8 @@ Expected<aarch32::EdgeKind_aarch32> getJITLinkEdgeKind(uint32_t ELFType) {
     return aarch32::Data_Delta32;
   case ELF::R_ARM_CALL:
     return aarch32::Arm_Call;
+  case ELF::R_ARM_JUMP24:
+    return aarch32::Arm_Jump24;
   case ELF::R_ARM_THM_CALL:
     return aarch32::Thumb_Call;
   case ELF::R_ARM_THM_JUMP24:
@@ -64,6 +66,8 @@ Expected<uint32_t> getELFRelocationType(Edge::Kind Kind) {
     return ELF::R_ARM_ABS32;
   case aarch32::Arm_Call:
     return ELF::R_ARM_CALL;
+  case aarch32::Arm_Jump24:
+    return ELF::R_ARM_JUMP24;
   case aarch32::Thumb_Call:
     return ELF::R_ARM_THM_CALL;
   case aarch32::Thumb_Jump24:

llvm/lib/ExecutionEngine/JITLink/aarch32.cpp

@@ -292,6 +292,11 @@ Expected<int64_t> readAddendArm(LinkGraph &G, Block &B, const Edge &E) {
       return makeUnexpectedOpcodeError(G, R, Kind);
     return decodeImmBA1BlA1BlxA2(R.Wd);
 
+  case Arm_Jump24:
+    if (!checkOpcode<Arm_Jump24>(R))
+      return makeUnexpectedOpcodeError(G, R, Kind);
+    return decodeImmBA1BlA1BlxA2(R.Wd);
+
   default:
     return make_error<JITLinkError>(
         "In graph " + G.getName() + ", section " + B.getSection().getName() +
@@ -399,10 +404,25 @@ Error applyFixupArm(LinkGraph &G, Block &B, const Edge &E) {
     TargetAddress |= 0x01;
 
   switch (Kind) {
+  case Arm_Jump24: {
+    if (!checkOpcode<Arm_Jump24>(R))
+      return makeUnexpectedOpcodeError(G, R, Kind);
+    if (hasTargetFlags(TargetSymbol, ThumbSymbol))
+      return make_error<JITLinkError>("Branch relocation needs interworking "
+                                      "stub when bridging to Thumb: " +
+                                      StringRef(G.getEdgeKindName(Kind)));
+
+    int64_t Value = TargetAddress - FixupAddress + Addend;
+
+    if (!isInt<26>(Value))
+      return makeTargetOutOfRangeError(G, B, E);
+    writeImmediate<Arm_Jump24>(R, encodeImmBA1BlA1BlxA2(Value));
+
+    return Error::success();
+  }
   case Arm_Call: {
     if (!checkOpcode<Arm_Call>(R))
       return makeUnexpectedOpcodeError(G, R, Kind);
-
     if ((R.Wd & FixupInfo<Arm_Call>::CondMask) !=
         FixupInfo<Arm_Call>::Unconditional)
       return make_error<JITLinkError>("Relocation expects an unconditional "
@@ -577,6 +597,7 @@ const char *getEdgeKindName(Edge::Kind K) {
     KIND_NAME_CASE(Data_Delta32)
     KIND_NAME_CASE(Data_Pointer32)
     KIND_NAME_CASE(Arm_Call)
+    KIND_NAME_CASE(Arm_Jump24)
     KIND_NAME_CASE(Thumb_Call)
     KIND_NAME_CASE(Thumb_Jump24)
     KIND_NAME_CASE(Thumb_MovwAbsNC)

llvm/test/ExecutionEngine/JITLink/AArch32/ELF_static_arm_reloc.s

@@ -30,6 +30,26 @@ call_target:
 	bx	lr
 	.size	call_target,	.-call_target
 
+# CHECK-TYPE: {{[0-9a-f]+}} R_ARM_JUMP24 jump24_target
+# CHECK-INSTR: 	00000008 <jump24_site>:
+# CHECK-INSTR: 	       8: eafffffe     b      0x8 <jump24_site>
+# CHECK-INSTR: 	0000000c <jump24_target>:
+# CHECK-INSTR: 	       c: e12fff1e     bx      lr
+# jitlink-check: decode_operand(jump24_site, 0) = jump24_target - (jump24_site + 8)
+	.globl	jump24_site
+	.type	jump24_site,%function
+	.p2align	2
+jump24_site:
+	b.w	jump24_target
+	.size	jump24_site,	.-jump24_site
+
+	.globl	jump24_target
+	.type	jump24_target,%function
+	.p2align	2
+jump24_target:
+	bx	lr
+	.size	jump24_target,	.-jump24_target
+
 # Empty main function for jitlink to be happy
 	.globl	main
 	.type	main,%function