[BOLT] Fix r_aarch64_prelxx test

The relocation value is calculated using the formula S + A - P,
the verification of the value is performed by inversely calculating the location address

Reviewed By: Amir

Differential Revision: https://reviews.llvm.org/D124270

Author: yavtuk

bolt/test/AArch64/r_aarch64_prelxx.s

@@ -0,0 +1,60 @@
+// This test checks processing of R_AARCH64_PREL64/32/16 relocations
+// S + A - P = Value
+// S = P - A + Value
+
+// mul(D1,0x100) == << 8
+// mul(D2,0x10000) == << 16
+// mul(D3,0x1000000) == << 24
+
+// REQUIRES: system-linux
+
+// RUN: %clang %cflags -nostartfiles -nostdlib %s -o %t.exe -mlittle-endian \
+// RUN:     -Wl,-q -Wl,-z,max-page-size=4
+// RUN: llvm-readelf -Wa %t.exe | FileCheck %s -check-prefix=CHECKPREL
+
+// CHECKPREL:       R_AARCH64_PREL16      {{.*}} .dummy + 0
+// CHECKPREL-NEXT:  R_AARCH64_PREL32      {{.*}} _start + 4
+// CHECKPREL-NEXT:  R_AARCH64_PREL64      {{.*}} _start + 8
+
+// RUN: llvm-bolt %t.exe -o %t.bolt
+// RUN: llvm-objdump -D %t.bolt | FileCheck %s --check-prefix=CHECKPREL32
+
+// CHECKPREL32: [[#%x,DATATABLEADDR:]] <datatable>:
+// CHECKPREL32-NEXT: 00:
+// CHECKPREL32-NEXT: 04: [[#%x,D0:]] [[#%x,D1:]] [[#%x,D2:]] [[#%x,D3:]]
+
+// 4 is offset in datatable
+// 8 is addend
+// CHECKPREL32: [[#DATATABLEADDR + 4 - 8 + D0 + mul(D1,0x100) + mul(D2,0x10000) + mul(D3,0x1000000)]] <_start>:
+
+// RUN: llvm-objdump -D %t.bolt | FileCheck %s --check-prefix=CHECKPREL64
+// CHECKPREL64: [[#%x,DATATABLEADDR:]] <datatable>:
+// CHECKPREL64-NEXT: 00:
+// CHECKPREL64-NEXT: 04:
+// CHECKPREL64-NEXT: 08: [[#%x,D0:]] [[#%x,D1:]] [[#%x,D2:]] [[#%x,D3:]]
+// CHECKPREL64-NEXT: 0c: 00 00 00 00
+
+// 8 is offset in datatable
+// 12 is addend
+// CHECKPREL64: [[#DATATABLEADDR + 8 - 12 + D0 + mul(D1,0x100) + mul(D2,0x10000) + mul(D3,0x1000000)]] <_start>:
+
+  .section .text
+  .align 4
+  .globl _start
+  .type _start, %function
+_start:
+  adr x0, datatable
+  mov x0, #0
+  ret 
+
+.section .dummy, "da"
+dummy:
+  .word 0
+
+  .data
+  .align 8
+datatable:
+  .hword dummy - datatable
+  .align 2
+  .word _start - datatable
+  .xword _start - datatable