[lld] c1a5f73 - [ELF][ARM] Represent R_ARM_LDO32 as R_DTPREL instead of R_ABS

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2020-07-06T09:47:53-07:00
New Revision: c1a5f73a4ae70d8f808c1bac091c3f4b683815b4

URL: https://github.com/llvm/llvm-project/commit/c1a5f73a4ae70d8f808c1bac091c3f4b683815b4
DIFF: https://github.com/llvm/llvm-project/commit/c1a5f73a4ae70d8f808c1bac091c3f4b683815b4.diff

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

Follow-up to D82899. Note, we need to disable R_DTPREL relaxation
because ARM psABI does not define TLS relaxation.

Reviewed By: grimar, psmith

Differential Revision: https://reviews.llvm.org/D83138

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/lld/ELF/Arch/ARM.cpp b/lld/ELF/Arch/ARM.cpp
index 0dfdbf3d01e2..fd90557cc4f6 100644
--- a/lld/ELF/Arch/ARM.cpp
+++ b/lld/ELF/Arch/ARM.cpp
@@ -121,6 +121,8 @@ RelExpr ARM::getRelExpr(RelType type, const Symbol &s,
     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

diff  --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
index dfae234fd60c..42341f67afee 100644
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -238,7 +238,7 @@ handleTlsRelocation(RelType type, Symbol &sym, InputSectionBase &c,
   }
 
   // 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});

diff  --git a/lld/test/ELF/debug-dead-reloc-tls-arm.s b/lld/test/ELF/debug-dead-reloc-tls-arm.s
index 146133a5c8c0..7fa5bcaae19e 100644
--- a/lld/test/ELF/debug-dead-reloc-tls-arm.s
+++ b/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: