[PATCH] D70204: [DWARF][RISCV] Resolve R_RISCV_32_PCREL

[Luís Marques via Phabricator via llvm-commits]

luismarques created this revision.
luismarques added reviewers: asb, lenary.
Herald added subscribers: llvm-commits, sameer.abuasal, pzheng, s.egerton, Jim, benna, psnobl, jocewei, PkmX, rkruppe, the_o, brucehoult, MartinMosbeck, rogfer01, edward-jones, zzheng, MaskRay, jrtc27, shiva0217, kito-cheng, niosHD, sabuasal, apazos, simoncook, johnrusso, rbar, hiraditya, aprantl.
Herald added a project: LLVM.

Add support for resolving `R_RISCV_32_PCREL` relocations. Those aren't actually resolved AFAIK, but support is still needed to avoid llvm-dwarfdump errors. The use of these relocations was introduced in D66419 <https://reviews.llvm.org/D66419> but the corresponding resolving wasn't added then*. The test adds a check that should catch future unresolved relocations.

*I would blame the reviewer, but it turns out that person was me, so he's exculpated.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D70204

Files:
  llvm/lib/Object/RelocationResolver.cpp
  llvm/test/DebugInfo/RISCV/relax-debug-frame.ll


Index: llvm/test/DebugInfo/RISCV/relax-debug-frame.ll
===================================================================
--- llvm/test/DebugInfo/RISCV/relax-debug-frame.ll
+++ llvm/test/DebugInfo/RISCV/relax-debug-frame.ll
@@ -1,7 +1,7 @@
 ; RUN: llc -filetype=obj -mtriple=riscv32 -mattr=+relax %s -o - \
 ; RUN:     | llvm-readobj -r | FileCheck -check-prefix=RELAX %s
 ; RUN: llc -filetype=obj -mtriple=riscv32 -mattr=+relax %s -o - \
-; RUN:     | llvm-dwarfdump --debug-frame - \
+; RUN:     | llvm-dwarfdump --debug-frame - 2>&1 \
 ; RUN:     | FileCheck -check-prefix=RELAX-DWARFDUMP %s
 ;
 ; RELAX: Section{{.*}}.rela.{{eh|debug}}_frame {
@@ -15,6 +15,7 @@
 ; RELAX: 0x25 R_RISCV_SET6
 ; RELAX: 0x25 R_RISCV_SUB6
 ;
+; RELAX-DWARFDUMP-NOT: error: failed to compute relocation
 ; RELAX-DWARFDUMP: CIE
 ; RELAX-DWARFDUMP: DW_CFA_advance_loc
 ; RELAX-DWARFDUMP: DW_CFA_def_cfa_offset
Index: llvm/lib/Object/RelocationResolver.cpp
===================================================================
--- llvm/lib/Object/RelocationResolver.cpp
+++ llvm/lib/Object/RelocationResolver.cpp
@@ -347,6 +347,7 @@
   case ELF::R_RISCV_SUB32:
   case ELF::R_RISCV_ADD64:
   case ELF::R_RISCV_SUB64:
+  case ELF::R_RISCV_32_PCREL:
     return true;
   default:
     return false;
@@ -360,6 +361,8 @@
     return A;
   case ELF::R_RISCV_32:
     return (S + RA) & 0xFFFFFFFF;
+  case ELF::R_RISCV_32_PCREL:
+    return (S + RA - R.getOffset()) & 0xFFFFFFFF;
   case ELF::R_RISCV_64:
     return S + RA;
   case ELF::R_RISCV_SET6:


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