PowerPC 32bit: Emit relocation type R_PPC_DTPREL32 for tls variablels.

[varunkumare99]

Summary

This patch emits the relocation type R_PPC_DTPREL32 for tls variables, which was previously emitting R_PPC_ADDR32 in power-pc 32bit.

[nemanjai]

The patch certainly seems reasonable to me. The test case seems like it could be trimmed down a bit (I don't think all the DWARF directives are needed).

[varunkumare99]

reduced the testcase.

[MaskRay]

llvm/test/MC/PowerPC/ppc32-R_PPC_DTPREL32-reloc.s

65

I think we should keep just this directive and delete other directives that are unrelated to the test.

## Used by DW_OP_form_tls_address
.long tls@DTPREL+32768

[varunkumare99]

llvm/test/MC/PowerPC/ppc32-R_PPC_DTPREL32-reloc.s

65

I have updated the testcase, as mentioned.

[nemanjai]

LGTM. Thanks.

[varunkumare99]

In D156953#4564564, @nemanjai wrote:

LGTM. Thanks.

Could you please commit the changes.
Name: Varun Erigila
Email: [e-mail]
Thanks

[MaskRay]

The test is overly complex as my last comment mentioned. I'll simplify the test case.

llvm/lib/Target/PowerPC/MCTargetDesc/PPCELFObjectWriter.cpp

case FK_Data_8:
         Type = ELF::R_PPC64_TPREL64;
         break;
       case MCSymbolRefExpr::VK_DTPREL:
         Type = ELF::R_PPC64_DTPREL64;
         break;
       }
       break;
     case FK_Data_4:
+      switch (Modifier) {
+      case MCSymbolRefExpr::VK_DTPREL:
+        Type = ELF::R_PPC_DTPREL32;
+        break;
+      default:
         Type = ELF::R_PPC_ADDR32;
+      }
       break;
     case FK_Data_2:
       Type = ELF::R_PPC_ADDR16;
       break;
     }
   }
   return Type;
 }

llvm/test/MC/PowerPC/ppc32-R_PPC_DTPREL32-reloc.s

+# RUN: llvm-mc -filetype=obj -triple=ppc %s -o %t
+# RUN: llvm-readelf -r %t | FileCheck %s 
+
+# CHECK: Relocation section '.rela.debug_info' at offset 0xf8 contains 1 entries:
+# CHECK-NEXT: Offset     Info    Type                Sym. Value  Symbol's Name + Addend
+# CHECK-NEXT: 00000000  0000024e R_PPC_DTPREL32         00000000   tls_rtp_var + 8000
+
+  .text
+  .globl  foo                             # -- Begin function foo
+  .p2align  2
+  .type foo,@function
+foo:                                    # @foo
+# %bb.0:                                # %entry
+  stwu 1, -16(1)
+  stw 31, 12(1)
+  mr  31, 1
+  addis 3, 2, tls_rtp_var@tprel@ha
+  addi 4, 3, tls_rtp_var@tprel@l
+  lwz 3, 0(4)
+  addi 3, 3, 1
+  stw 3, 0(4)
+  lis 4, my_global_var@ha
+  lwz 3, my_global_var@l(4)
+  addi 3, 3, 1
+  stw 3, my_global_var@l(4)
+  lwz 31, 12(1)
+  addi 1, 1, 16
+  blr
+
+  .type tls_rtp_var,@object             # @tls_rtp_var
+  .section  .tdata,"awT",@progbits
+  .globl  tls_rtp_var
+  .p2align  2, 0x0
+tls_rtp_var:
+  .long 5                               # 0x5
+  .size tls_rtp_var, 4
+
+  .type my_global_var,@object           # @my_global_var
+  .data
+  .globl  my_global_var
+  .p2align  2, 0x0
+my_global_var:
+  .long 7                               # 0x7
+  .size my_global_var, 4
+
+  .section  .debug_info,"",@progbits
+.Lcu_begin0:
+.Ldebug_info_start0:
+  .long tls_rtp_var@DTPREL+32768
+.Ldebug_info_end0: