[AMDGPU][MC] Generate relative relocations for allocatable (more particularly, eh_frame) sections

Reviewed By: scott.linder

Differential Revision: https://reviews.llvm.org/D142453

Author: jmmartinez

llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFObjectWriter.cpp

@@ -74,9 +74,9 @@ unsigned AMDGPUELFObjectWriter::getRelocType(MCContext &Ctx,
     return ELF::R_AMDGPU_REL32;
   case FK_Data_4:
   case FK_SecRel_4:
-    return ELF::R_AMDGPU_ABS32;
+    return IsPCRel ? ELF::R_AMDGPU_REL32 : ELF::R_AMDGPU_ABS32;
   case FK_Data_8:
-    return ELF::R_AMDGPU_ABS64;
+    return IsPCRel ? ELF::R_AMDGPU_REL64 : ELF::R_AMDGPU_ABS64;
   }
 
   if (Fixup.getTargetKind() == AMDGPU::fixup_si_sopp_br) {

llvm/test/MC/AMDGPU/cfi_reloc.s

@@ -0,0 +1,16 @@
+// RUN: llvm-mc -filetype=obj -triple amdgcn-- -mcpu=kaveri -show-encoding %s | llvm-readobj -r - | FileCheck %s
+
+// CHECK: Relocations [
+// CHECK: .rel.eh_frame {
+// CHECK: R_AMDGPU_REL32 .text
+// CHECK: }
+// CHECK: .rel.debug_frame {
+// CHECK: R_AMDGPU_ABS64 .text
+// CHECK: }
+// CHECK: ]
+
+kernel:
+  .cfi_startproc
+  .cfi_sections .debug_frame, .eh_frame
+  s_endpgm
+  .cfi_endproc