[JITLink][ELF/AARCH64] Implement R_AARCH64_JUMP26

[sunho]

Summary

This patch implemetns R_AARCH64_JUMP26. We can use the same generic aarch64 Branch26 edge since B instruction and BL nstruction have the same sized&offseted immediate field and the relocation address calculation is the same.

Reference: ELF for the ARM ® 64-bit Architecture Tabel 4-10, ARM Architecture Reference Manual ® ARMv8, for ARMv8-A architecture profile C6.2.24, C6.2.31

[sgraenitz]

LGTM

llvm/lib/ExecutionEngine/JITLink/ELF_aarch64.cpp

 template <typename ELFT>
 class ELFLinkGraphBuilder_aarch64 : public ELFLinkGraphBuilder<ELFT> {
 private:
   static Expected<ELF_aarch64_Edges::ELFAArch64RelocationKind>
   getRelocationKind(const uint32_t Type) {
     using namespace aarch64;
     switch (Type) {
     case ELF::R_AARCH64_CALL26:
+    case ELF::R_AARCH64_JUMP26:
       return ELFCall26;
     case ELF::R_AARCH64_ADR_PREL_PG_HI21:
       return ELFAdrPage21;
     case ELF::R_AARCH64_ADD_ABS_LO12_NC:
       return ELFAddAbs12;
     case ELF::R_AARCH64_LDST8_ABS_LO12_NC:
       return ELFLdSt8Abs12;
     case ELF::R_AARCH64_LDST16_ABS_LO12_NC:

llvm/test/ExecutionEngine/JITLink/AArch64/ELF_aarch64_relocations.s

 # RUN: rm -rf %t && mkdir -p %t
 # RUN: llvm-mc -triple=aarch64-unknown-linux-gnu -relax-relocations=false -position-independent -filetype=obj -o %t/elf_reloc.o %s
 # RUN: llvm-jitlink -noexec \
 # RUN:              -abs external_data=0xdeadbeef \
 # RUN:              -check %s %t/elf_reloc.o
 
         .text
 
         .globl  main
         .p2align  2
         .type main,@function
 main:
         ret
 
         .size   main, .-main
 
-# Check R_AARCH64_CALL26 relocation of a local function call
+# Check R_AARCH64_CALL26 / R_AARCH64_JUMP26 relocation of a local function call
 #
 # jitlink-check: decode_operand(local_func_call26, 0)[25:0] = (local_func - local_func_call26)[27:2]
+# jitlink-check: decode_operand(local_func_jump26, 0)[25:0] = (local_func - local_func_jump26)[27:2]
         .globl  local_func
         .p2align  2
         .type local_func,@function
 local_func:
         ret
         .size   local_func, .-local_func
 
         .globl  local_func_call26
         .p2align  2
 local_func_call26:
         bl  local_func
         .size   local_func_call26, .-local_func_call26
 
+        .globl  local_func_jump26
+        .p2align  2
+local_func_jump26:
+        b local_func
+        .size   local_func_jump26, .-local_func_jump26
 
 # Check R_AARCH64_ADR_PREL_PG_HI21 / R_AARCH64_ADD_ABS_LO12_NC relocation of a local symbol
 #
 # For the ADR_PREL_PG_HI21/ADRP instruction we have the 21-bit delta to the 4k page
 # containing the global.
 #
 # jitlink-check: decode_operand(test_adr_prel, 1) = (named_data - test_adr_prel)[32:12]
 # jitlink-check: decode_operand(test_add_abs_lo12, 2) = (named_data + 0)[11:0]