[ELF/AARCH64] - Implemented R_AARCH64_IRELATIVE relocation.

[grimar]

Summary

Implemented in the same way as was already done for x86/x64 targets (http://reviews.llvm.org/D15235).

[emaste]

ELF/Target.cpp

1127 ↗

(On Diff #43732)

Absent other reasons to order these in a specific way should it be in alpha order?

[grimar]

ELF/Target.cpp

1127 ↗

(On Diff #43732)

I dont think we have any order for that in other targets. I'm not sure that this much sense to order it, but I just did it to be on a safe side.

[ruiu]

LGTM

lld/trunk/ELF/Target.cpp

case R_PPC64_TOC:
     break;
   default:
     error("unrecognized reloc " + Twine(Type));
   }
 }
 
 AArch64TargetInfo::AArch64TargetInfo() {
   CopyReloc = R_AARCH64_COPY;
+  IRelativeReloc = R_AARCH64_IRELATIVE;
   GotReloc = R_AARCH64_GLOB_DAT;
   PltReloc = R_AARCH64_JUMP_SLOT;
   LazyRelocations = true;
   PltEntrySize = 16;
   PltZeroEntrySize = 32;
 }
 
 unsigned AArch64TargetInfo::getDynReloc(unsigned Type) const {

 bool AArch64TargetInfo::relocNeedsGot(uint32_t Type,
                                       const SymbolBody &S) const {
   return Type == R_AARCH64_ADR_GOT_PAGE || Type == R_AARCH64_LD64_GOT_LO12_NC ||
          relocNeedsPlt(Type, S);
 }
 
 bool AArch64TargetInfo::relocNeedsPlt(uint32_t Type,
                                       const SymbolBody &S) const {
+  if (isGnuIFunc<ELF64LE>(S))
+    return true;
   switch (Type) {
   default:
     return false;
   case R_AARCH64_CALL26:
   case R_AARCH64_JUMP26:
     return canBePreempted(&S, true);
   }
 }

lld/trunk/test/ELF/aarch64-gnu-ifunc-nosym.s

+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-linux-gnu %s -o %t.o
+// RUN: ld.lld -static %t.o -o %tout
+// RUN: llvm-readobj -symbols %tout | FileCheck %s
+// REQUIRES: aarch64
+
+// Check that no __rela_iplt_end/__rela_iplt_start
+// appear in symtab if there is no references to them.
+// CHECK:      Symbols [
+// CHECK-NEXT-NOT: __rela_iplt_end
+// CHECK-NEXT-NOT: __rela_iplt_start
+// CHECK: ]
+
+.text
+.type foo STT_GNU_IFUNC
+.globl foo
+.type foo, @function
+foo:
+ ret
+
+.type bar STT_GNU_IFUNC
+.globl bar
+.type bar, @function
+bar:
+ ret
+
+.globl _start
+_start:
+ bl foo
+ bl bar

lld/trunk/test/ELF/aarch64-gnu-ifunc.s

+// RUN: llvm-mc -filetype=obj -triple=aarch64-none-linux-gnu %s -o %t.o
+// RUN: ld.lld -static %t.o -o %tout
+// RUN: llvm-objdump -d %tout | FileCheck %s --check-prefix=DISASM
+// RUN: llvm-readobj -r -symbols -sections %tout | FileCheck %s --check-prefix=CHECK
+// REQUIRES: aarch64
+
+// CHECK:      Sections [
+// CHECK:       Section {
+// CHECK:       Index: 1
+// CHECK-NEXT:  Name: .rela.plt
+// CHECK-NEXT:  Type: SHT_RELA
+// CHECK-NEXT:  Flags [
+// CHECK-NEXT:    SHF_ALLOC
+// CHECK-NEXT:  ]
+// CHECK-NEXT:  Address: [[RELA:.*]]
+// CHECK-NEXT:  Offset: 0x158
+// CHECK-NEXT:  Size: 48
+// CHECK-NEXT:  Link: 5
+// CHECK-NEXT:  Info: 0
+// CHECK-NEXT:  AddressAlignment: 8
+// CHECK-NEXT:  EntrySize: 24
+// CHECK-NEXT: }
+// CHECK:      Relocations [
+// CHECK-NEXT:   Section ({{.*}}) .rela.plt {
+// CHECK-NEXT:     0x12018 R_AARCH64_IRELATIVE
+// CHECK-NEXT:     0x12020 R_AARCH64_IRELATIVE
+// CHECK-NEXT:   }
+// CHECK-NEXT: ]
+// CHECK:      Symbols [
+// CHECK-NEXT:  Symbol {
+// CHECK-NEXT:    Name:
+// CHECK-NEXT:    Value: 0x0
+// CHECK-NEXT:    Size: 0
+// CHECK-NEXT:    Binding: Local
+// CHECK-NEXT:    Type: None
+// CHECK-NEXT:    Other: 0
+// CHECK-NEXT:    Section: Undefined
+// CHECK-NEXT:  }
+// CHECK-NEXT:  Symbol {
+// CHECK-NEXT:    Name: $x.0
+// CHECK-NEXT:    Value: 0x11000
+// CHECK-NEXT:    Size: 0
+// CHECK-NEXT:    Binding: Local
+// CHECK-NEXT:    Type: None
+// CHECK-NEXT:    Other: 0
+// CHECK-NEXT:    Section: .text
+// CHECK-NEXT:  }
+// CHECK-NEXT:  Symbol {
+// CHECK-NEXT:    Name: __rela_iplt_end
+// CHECK-NEXT:    Value: 0x10188
+// CHECK-NEXT:    Size: 0
+// CHECK-NEXT:    Binding: Local
+// CHECK-NEXT:    Type: None
+// CHECK-NEXT:    Other: 0
+// CHECK-NEXT:    Section: Absolute
+// CHECK-NEXT:  }
+// CHECK-NEXT:  Symbol {
+// CHECK-NEXT:    Name: __rela_iplt_start
+// CHECK-NEXT:    Value: 0x10158
+// CHECK-NEXT:    Size: 0
+// CHECK-NEXT:    Binding: Local
+// CHECK-NEXT:    Type: None
+// CHECK-NEXT:    Other: 0
+// CHECK-NEXT:    Section: Absolute
+// CHECK-NEXT:  }
+// CHECK-NEXT:  Symbol {
+// CHECK-NEXT:    Name: _start
+// CHECK-NEXT:    Value: 0x11008
+// CHECK-NEXT:    Size: 0
+// CHECK-NEXT:    Binding: Global
+// CHECK-NEXT:    Type: None
+// CHECK-NEXT:    Other: 0
+// CHECK-NEXT:    Section: .text
+// CHECK-NEXT:  }
+// CHECK-NEXT:  Symbol {
+// CHECK-NEXT:    Name: bar
+// CHECK-NEXT:    Value: 0x11004
+// CHECK-NEXT:    Size: 0
+// CHECK-NEXT:    Binding: Global
+// CHECK-NEXT:    Type: GNU_IFunc
+// CHECK-NEXT:    Other: 0
+// CHECK-NEXT:    Section: .text
+// CHECK-NEXT:  }
+// CHECK-NEXT:  Symbol {
+// CHECK-NEXT:    Name: foo
+// CHECK-NEXT:    Value: 0x11000
+// CHECK-NEXT:    Size: 0
+// CHECK-NEXT:    Binding: Global
+// CHECK-NEXT:    Type: GNU_IFunc
+// CHECK-NEXT:    Other: 0
+// CHECK-NEXT:    Section: .text
+// CHECK-NEXT:  }
+// CHECK-NEXT: ]
+
+// 344 = 0x158
+// 392 = 0x188
+// DISASM:      Disassembly of section .text:
+// DISASM-NEXT: foo:
+// DISASM-NEXT:  11000: c0 03 5f d6 ret
+// DISASM:      bar:
+// DISASM-NEXT:  11004: c0 03 5f d6 ret
+// DISASM:      _start:
+// DISASM-NEXT:  11008: 0e 00 00 94 bl #56
+// DISASM-NEXT:  1100c: 11 00 00 94 bl #68
+// DISASM-NEXT:  11010: 42 60 05 91 add x2, x2, #344
+// DISASM-NEXT:  11014: 42 20 06 91 add x2, x2, #392
+// DISASM-NEXT: Disassembly of section .plt:
+// DISASM-NEXT: .plt:
+// DISASM-NEXT:  11020: f0 7b bf a9 stp x16, x30, [sp, #-16]!
+// DISASM-NEXT:  11024: 10 00 00 b0 adrp x16, #4096
+// DISASM-NEXT:  11028: 11 0a 40 f9 ldr x17, [x16, #16]
+// DISASM-NEXT:  1102c: 10 42 00 91 add x16, x16, #16
+// DISASM-NEXT:  11030: 20 02 1f d6 br x17
+// DISASM-NEXT:  11034: 1f 20 03 d5 nop
+// DISASM-NEXT:  11038: 1f 20 03 d5 nop
+// DISASM-NEXT:  1103c: 1f 20 03 d5 nop
+// DISASM-NEXT:  11040: 10 00 00 b0 adrp x16, #4096
+// DISASM-NEXT:  11044: 11 0e 40 f9 ldr x17, [x16, #24]
+// DISASM-NEXT:  11048: 10 62 00 91 add x16, x16, #24
+// DISASM-NEXT:  1104c: 20 02 1f d6 br x17
+// DISASM-NEXT:  11050: 10 00 00 b0 adrp x16, #4096
+// DISASM-NEXT:  11054: 11 12 40 f9 ldr x17, [x16, #32]
+// DISASM-NEXT:  11058: 10 82 00 91 add x16, x16, #32
+// DISASM-NEXT:  1105c: 20 02 1f d6 br x17
+
+.text
+.type foo STT_GNU_IFUNC
+.globl foo
+.type foo, @function
+foo:
+ ret
+
+.type bar STT_GNU_IFUNC
+.globl bar
+.type bar, @function
+bar:
+ ret
+
+.globl _start
+_start:
+ bl foo
+ bl bar
+ add x2, x2, :lo12:__rela_iplt_start
+ add x2, x2, :lo12:__rela_iplt_end