[NativeAOT] ELF ARM: Produce different relocation type for B and BL

[filipnavara]

Release builds produce tail calls. When the target of a tail call is external function it was generated with B.W instruction and R_ARM_THM_CALL relocation. The linker then incorrectly overwrote some bits of the instruction.

Object file:

000564b0 <System.Math__Ceiling>:
   564b0:       b508            push    {r3, lr}
   564b2:       b001            add     sp, #4
   564b4:       f85d eb04       ldr.w   lr, [sp], #4
   564b8:       f7ff bffe       b.w     0 <ceil>
   564bc:       0000            movs    r0, r0

Incorrectly linked executable:

002a6f60 <System.Math__Ceiling>:
  2a6f60:       b508            push    {r3, lr}
  2a6f62:       b001            add     sp, #4
  2a6f64:       f85d eb04       ldr.w   lr, [sp], #4
  2a6f68:       f14a afba       bpl.w   371ee0
  2a6f6c:       0000            movs    r0, r0

Correctly linked executable:

002a6f60 <System.Math__Ceiling>:
  2a6f60:       b508            push    {r3, lr}
  2a6f62:       b001            add     sp, #4
  2a6f64:       f85d eb04       ldr.w   lr, [sp], #4
  2a6f68:       f149 beb8       b.w     3f0cdc <__ThumbV7PILongThunk_ceil>
  2a6f6c:       0000            movs    r0, r0

Contributes to #97729

[ghost]

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Release builds produce tail calls. When the target of a tail call is external function it was generated with B.W instruction and R_ARM_THM_CALL relocation. The linker then incorrectly overwrote some bits of the instruction.

Object file:

000564b0 <System.Math__Ceiling>:
   564b0:       b508            push    {r3, lr}
   564b2:       b001            add     sp, #4
   564b4:       f85d eb04       ldr.w   lr, [sp], #4
   564b8:       f7ff bffe       b.w     0 <ceil>
   564bc:       0000            movs    r0, r0

Incorrectly linked executable:

002a6f60 <System.Math__Ceiling>:
  2a6f60:       b508            push    {r3, lr}
  2a6f62:       b001            add     sp, #4
  2a6f64:       f85d eb04       ldr.w   lr, [sp], #4
  2a6f68:       f14a afba       bpl.w   371ee0
  2a6f6c:       0000            movs    r0, r0

Author:	filipnavara
Assignees:	-
Labels:	area-NativeAOT-coreclr
Milestone:	-

[jkotas]

Thanks