[lld] r268565 - [ELF][MIPS] Create combined dynamic relocation type R_MIPS_REL32/R_MIPS_64/R_MIPS_NONE

[Simon Atanasyan via llvm-commits]

Author: atanasyan
Date: Wed May  4 17:39:40 2016
New Revision: 268565

URL: http://llvm.org/viewvc/llvm-project?rev=268565&view=rev
Log:
[ELF][MIPS] Create combined dynamic relocation type R_MIPS_REL32/R_MIPS_64/R_MIPS_NONE

MIPS N64 ABI packs multiple relocations into the single relocation
record. Particularly it requires to represent dynamic relative
relocation as a combination of R_MIPS_REL32 and R_MIPS_64 relocations.

Added:
    lld/trunk/test/ELF/mips-64.s
Modified:
    lld/trunk/ELF/Target.cpp

Modified: lld/trunk/ELF/Target.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Target.cpp?rev=268565&r1=268564&r2=268565&view=diff
==============================================================================
--- lld/trunk/ELF/Target.cpp (original)
+++ lld/trunk/ELF/Target.cpp Wed May  4 17:39:40 2016
@@ -1235,7 +1235,10 @@ template <class ELFT> MipsTargetInfo<ELF
   UseLazyBinding = true;
   CopyRel = R_MIPS_COPY;
   PltRel = R_MIPS_JUMP_SLOT;
-  RelativeRel = R_MIPS_REL32;
+  if (ELFT::Is64Bits)
+    RelativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32;
+  else
+    RelativeRel = R_MIPS_REL32;
 }
 
 template <class ELFT>
@@ -1286,7 +1289,7 @@ RelExpr MipsTargetInfo<ELFT>::getRelExpr
 template <class ELFT>
 uint32_t MipsTargetInfo<ELFT>::getDynRel(uint32_t Type) const {
   if (Type == R_MIPS_32 || Type == R_MIPS_64)
-    return R_MIPS_REL32;
+    return RelativeRel;
   StringRef S = getELFRelocationTypeName(EM_MIPS, Type);
   error("relocation " + S + " cannot be used when making a shared object; "
                             "recompile with -fPIC.");
@@ -1452,6 +1455,9 @@ void MipsTargetInfo<ELFT>::relocateOne(u
   case R_MIPS_32:
     write32<E>(Loc, Val);
     break;
+  case R_MIPS_64:
+    write64<E>(Loc, Val);
+    break;
   case R_MIPS_26: {
     uint32_t Instr = read32<E>(Loc);
     write32<E>(Loc, (Instr & ~0x3ffffff) | (Val >> 2));

Added: lld/trunk/test/ELF/mips-64.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-64.s?rev=268565&view=auto
==============================================================================
--- lld/trunk/test/ELF/mips-64.s (added)
+++ lld/trunk/test/ELF/mips-64.s Wed May  4 17:39:40 2016
@@ -0,0 +1,67 @@
+# Check R_MIPS_64 relocation calculation.
+
+# RUN: llvm-mc -filetype=obj -triple=mips64-unknown-linux %s -o %t.o
+# RUN: ld.lld -shared %t.o -o %t.so
+# RUN: llvm-objdump -t -s %t.so | FileCheck -check-prefix=SYM %s
+# RUN: llvm-readobj -r -dynamic-table -mips-plt-got %t.so | FileCheck %s
+
+# REQUIRES: mips
+
+  .global  __start
+__start:
+  nop
+
+  .data
+  .type  v1, at object
+  .size  v1,4
+v1:
+  .quad 0
+
+  .globl v2
+  .type  v2, at object
+  .size  v2,8
+v2:
+  .quad v2+8 # R_MIPS_64 target v2 addend 8
+  .quad v1   # R_MIPS_64 target v1 addend 0
+
+# SYM: Contents of section .data:
+# SYM-NEXT: 30000 00000000 00000000 00000000 00000000
+#                                   ^-- v2
+# SYM-NEXT: 30010 00000000 00030000
+#                 ^-- v1
+
+# SYM: SYMBOL TABLE:
+# SYM: 00030000 l       .data           00000004 v1
+# SYM: 00030008 g       .data           00000008 v2
+
+# CHECK:      Relocations [
+# CHECK-NEXT:   Section (7) .rela.dyn {
+# CHECK-NEXT:     0x30008 R_MIPS_REL32/R_MIPS_64/R_MIPS_NONE v2 0x8
+# CHECK-NEXT:     0x30010 R_MIPS_REL32/R_MIPS_64/R_MIPS_NONE - 0x30000
+# CHECK-NEXT:   }
+# CHECK-NEXT: ]
+
+# CHECK: DynamicSection [
+# CHECK:   Tag        Type     Name/Value
+# CHECK:   0x0000000000000008 RELASZ    48 (bytes)
+# CHECK:   0x0000000000000009 RELAENT   24 (bytes)
+
+# CHECK:      Primary GOT {
+# CHECK-NEXT:   Canonical gp value:
+# CHECK-NEXT:   Reserved entries [
+# CHECK:        ]
+# CHECK-NEXT:   Local entries [
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Global entries [
+# CHECK-NEXT:     Entry {
+# CHECK-NEXT:       Address:
+# CHECK-NEXT:       Access:
+# CHECK-NEXT:       Initial: 0x30008
+# CHECK-NEXT:       Value: 0x30008
+# CHECK-NEXT:       Type: Object
+# CHECK-NEXT:       Section: .data
+# CHECK-NEXT:       Name: v2
+# CHECK-NEXT:     }
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Number of TLS and multi-GOT entries: 0
+# CHECK-NEXT: }