[PATCH] D60994: [PPC64] Allow R_PPC64_DTPREL* to preemptable local-dynamic symbols

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added a reviewer: ruiu.
Herald added subscribers: llvm-commits, jsji, kbarton, arichardson, nemanjai, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.

Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D60994

Files:
  ELF/Arch/PPC64.cpp
  ELF/InputSection.cpp
  ELF/Relocations.cpp
  test/ELF/ppc64-tls-ld-preemptable.s


Index: test/ELF/ppc64-tls-ld-preemptable.s
===================================================================
--- /dev/null
+++ test/ELF/ppc64-tls-ld-preemptable.s
@@ -0,0 +1,36 @@
+# REQUIRES: ppc
+# RUN: llvm-mc -filetype=obj -triple=ppc64le %s -o %t.o
+# RUN: ld.lld %t.o -shared -o %t.so
+# RUN: llvm-objdump -d --no-show-raw-insn %t.so | FileCheck %s
+# RUN: llvm-nm %t.so | FileCheck --check-prefix=NM %s
+# RUN: llvm-readelf -x .rodata %t.so | FileCheck --check-prefix=RODATA %s
+
+# 42 - 0x8000 = -32726
+# CHECK:      addis 4, 3, 0
+# CHECK-NEXT: addi 4, 3, -32726
+# CHECK-NEXT: lwz 0, 0(4)
+# CHECK-NEXT: lis 5, 0
+# CHECK-NEXT: ori 5, 5, 0
+
+# NM: 000000000000002a B i
+# RODATA: 2a000000 00000000
+
+# We used to error on R_PPC64_DTPREL* to preemptable symbols.
+# i is STB_GLOBAL and preemptable.
+.globl foo
+foo:
+  addis 4, 3, i at dtprel@ha # R_PPC64_DTPREL16_HA
+  addi 4, 4, i at dtprel@l   # R_PPC64_DTPREL16_LO
+
+  lis 5, i at dtprel@highesta # R_PPC64_DTPREL16_HIGHESTA
+  ori 5, 5, i at dtprel@highera # R_PPC64_DTPREL16_HIGHERA
+
+.section .rodata,"a", at progbits
+.quad i at dtprel+32768
+
+.section .tbss,"awT", at nobits
+  .space 42
+.globl i
+i:
+  .long 0
+  .size i, 4
Index: ELF/Relocations.cpp
===================================================================
--- ELF/Relocations.cpp
+++ ELF/Relocations.cpp
@@ -248,8 +248,7 @@
   }
 
   // Local-Dynamic relocs can be relaxed to Local-Exec.
-  // TODO Delete R_ABS after all R_*_DTPREL_* relocations migrate to R_DTPREL.
-  if ((Expr == R_ABS || Expr == R_DTPREL) && !Config->Shared) {
+  if (Expr == R_DTPREL && !Config->Shared) {
     C.Relocations.push_back(
         {Target->adjustRelaxExpr(Type, nullptr, R_RELAX_TLS_LD_TO_LE), Type,
          Offset, Addend, &Sym});
Index: ELF/InputSection.cpp
===================================================================
--- ELF/InputSection.cpp
+++ ELF/InputSection.cpp
@@ -615,11 +615,10 @@
                                  uint64_t P, const Symbol &Sym, RelExpr Expr) {
   switch (Expr) {
   case R_ABS:
+  case R_DTPREL:
   case R_RELAX_TLS_LD_TO_LE_ABS:
   case R_RELAX_GOT_PC_NOPIC:
     return Sym.getVA(A);
-  case R_DTPREL:
-    return Sym.getVA(A);
   case R_ADDEND:
     return A;
   case R_ARM_SBREL:
Index: ELF/Arch/PPC64.cpp
===================================================================
--- ELF/Arch/PPC64.cpp
+++ ELF/Arch/PPC64.cpp
@@ -496,7 +496,7 @@
   case R_PPC64_DTPREL16_LO:
   case R_PPC64_DTPREL16_LO_DS:
   case R_PPC64_DTPREL64:
-    return R_ABS;
+    return R_DTPREL;
   case R_PPC64_TLSGD:
     return R_TLSDESC_CALL;
   case R_PPC64_TLSLD:


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