[PATCH] D83138: [ELF][ARM] Represent R_ARM_LDO32 as R_DTPREL instead of R_ABS

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: grimar, psmith, ruiu.
Herald added subscribers: llvm-commits, danielkiss, kristof.beyls, arichardson, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.

Follow-up to D82899 <https://reviews.llvm.org/D82899>. Note, we need to disable R_DTPREL relaxation
because ARM psABI does not define TLS relaxation.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D83138

Files:
  lld/ELF/Arch/ARM.cpp
  lld/ELF/Relocations.cpp
  lld/test/ELF/debug-dead-reloc-tls-arm.s


Index: lld/test/ELF/debug-dead-reloc-tls-arm.s
===================================================================
--- lld/test/ELF/debug-dead-reloc-tls-arm.s
+++ lld/test/ELF/debug-dead-reloc-tls-arm.s
@@ -7,8 +7,7 @@
 # RUN: llvm-objdump -s %t | FileCheck %s
 
 # CHECK:      Contents of section .debug_info:
-## FIXME: Use ffffffff
-# CHECK-NEXT:  0000 00000000
+# CHECK-NEXT:  0000 ffffffff
 
 .globl _start
 _start:
Index: lld/ELF/Relocations.cpp
===================================================================
--- lld/ELF/Relocations.cpp
+++ lld/ELF/Relocations.cpp
@@ -238,7 +238,7 @@
   }
 
   // Local-Dynamic relocs can be relaxed to Local-Exec.
-  if (expr == R_DTPREL && !config->shared) {
+  if (expr == R_DTPREL && canRelax && !config->shared) {
     c.relocations.push_back(
         {target->adjustRelaxExpr(type, nullptr, R_RELAX_TLS_LD_TO_LE), type,
          offset, addend, &sym});
Index: lld/ELF/Arch/ARM.cpp
===================================================================
--- lld/ELF/Arch/ARM.cpp
+++ lld/ELF/Arch/ARM.cpp
@@ -121,6 +121,8 @@
     return R_TLSGD_PC;
   case R_ARM_TLS_LDM32:
     return R_TLSLD_PC;
+  case R_ARM_TLS_LDO32:
+    return R_DTPREL;
   case R_ARM_BASE_PREL:
     // B(S) + A - P
     // FIXME: currently B(S) assumed to be .got, this may not hold for all


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