[ELF][MIPS] Support R_MIPS_COPY relocation

Generate R_MIPS_COPY relocation for 'static' relocations against object symbols defined in a shared libraries. llvm-svn: 260083
llvm · Feb 8, 2016 · e1bfc2e · e1bfc2e
1 parent ed203da
commit e1bfc2e
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diff --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
@@ -196,6 +196,7 @@ template <class ELFT> class MipsTargetInfo final : public TargetInfo {
   MipsTargetInfo();
   unsigned getDynRel(unsigned Type) const override;
   void writeGotHeader(uint8_t *Buf) const override;
+  bool needsCopyRel(uint32_t Type, const SymbolBody &S) const override;
   bool needsGot(uint32_t Type, const SymbolBody &S) const override;
   bool needsPlt(uint32_t Type, const SymbolBody &S) const override;
   void relocateOne(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type, uint64_t P,
@@ -1386,6 +1387,7 @@ void AMDGPUTargetInfo::relocateOne(uint8_t *Loc, uint8_t *BufEnd, uint32_t Type,
 }
 
 template <class ELFT> MipsTargetInfo<ELFT>::MipsTargetInfo() {
+  CopyRel = R_MIPS_COPY;
   PageSize = 65536;
   GotHeaderEntriesNum = 2;
   RelativeRel = R_MIPS_REL32;
@@ -1425,6 +1427,17 @@ void MipsTargetInfo<ELFT>::writeGotHeader(uint8_t *Buf) const {
   P[1] = uintX_t(1) << (ELFT::Is64Bits ? 63 : 31);
 }
 
+template <class ELFT>
+bool MipsTargetInfo<ELFT>::needsCopyRel(uint32_t Type,
+                                        const SymbolBody &S) const {
+  if (Config->Shared)
+    return false;
+  if (Type == R_MIPS_HI16 || Type == R_MIPS_LO16 || isRelRelative(Type))
+    if (auto *SS = dyn_cast<SharedSymbol<ELFT>>(&S))
+      return SS->Sym.getType() == STT_OBJECT;
+  return false;
+}
+
 template <class ELFT>
 bool MipsTargetInfo<ELFT>::needsGot(uint32_t Type, const SymbolBody &S) const {
   return Type == R_MIPS_GOT16 || Type == R_MIPS_CALL16;

diff --git a/lld/test/ELF/Inputs/mips-dynamic.s b/lld/test/ELF/Inputs/mips-dynamic.s
@@ -1,4 +1,21 @@
+  .option pic2
   .text
   .globl _foo
 _foo:
   nop
+
+  .globl foo
+  .type foo, @function
+foo:
+  nop
+
+  .data
+  .globl data0
+  .type data0, @object
+data0:
+  .word 0
+
+  .globl data1
+  .type data1, @object
+data1:
+  .word 0
diff --git a/lld/test/ELF/mips-plt-copy.s b/lld/test/ELF/mips-plt-copy.s
@@ -0,0 +1,42 @@
+# Check creating of R_MIPS_COPY dynamic relocation.
+
+# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux %s -o %t.o
+# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux \
+# RUN:         %S/Inputs/mips-dynamic.s -o %t.so.o
+# RUN: ld.lld %t.so.o -shared -o %t.so
+# RUN: ld.lld %t.o %t.so -o %t.exe
+# RUN: llvm-readobj -r -mips-plt-got %t.exe | FileCheck %s
+
+# REQUIRES: mips
+
+# CHECK:      Relocations [
+# CHECK-NEXT:   Section (7) .rel.dyn {
+# CHECK-NEXT:     0x{{[0-9A-F]+}} R_MIPS_COPY data0 0x0
+# CHECK-NEXT:     0x{{[0-9A-F]+}} R_MIPS_COPY data1 0x0
+# CHECK-NEXT:   }
+# CHECK-NEXT: ]
+
+# CHECK:      Primary GOT {
+# CHECK:        Local entries [
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Global entries [
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Number of TLS and multi-GOT entries: 0
+# CHECK-NEXT: }
+
+  .text
+  .globl __start
+__start:
+  lui    $t0,%hi(data0)    # R_MIPS_HI16 requires COPY rel for DSO defined data.
+  addi   $t0,$t0,%lo(data0)
+  lui    $t0,%hi(gd)       # Does not require COPY rel for locally defined data.
+  addi   $t0,$t0,%lo(gd)
+  lui    $t0,%hi(ld)       # Does not require COPY rel for local data.
+  addi   $t0,$t0,%lo(ld)
+
+  .data
+  .globl gd
+gd:
+  .word 0
+ld:
+  .word data1+8-.          # R_MIPS_PC32 requires COPY rel for DSO defined data.