[BOLT] Add R_AARCH64_PREL16/32/64 relocations support

[yota9]

LGTM

[rafauler]

Looks good, thanks! Next time, could you submit the diff with full context? It says "context not available" when we try to browse the changes.

[rafauler]

Oh, now I can see the context. Something weird happening with my UI.

[yavtuk]

Hi folks, do you have any updates or notes?

[rafauler]

No, this is good to go.

[yavtuk]

the latest CI stats:

---

Timed Out Tests (5):

MLIR :: Examples/standalone/test.toy
libFuzzer :: fuzzer-leak.test
libFuzzer :: large.test
libFuzzer :: out-of-process-fuzz.test
libFuzzer :: value-profile-load.test

I think this is not related to current patch

[Amir]

The test is broken on aarch64 ubuntu buildbot: http://157.230.108.44:8011/#/builders/51/builds/582

[yavtuk]

@Amir thanks, I'll try to fix it as soon as possiblе

bolt/include/bolt/Core/BinaryFunction.h

void addRelocationAArch64(uint64_t Offset, MCSymbol *Symbol, uint64_t RelType,
     case ELF::R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
     case ELF::R_AARCH64_MOVW_UABS_G0:
     case ELF::R_AARCH64_MOVW_UABS_G0_NC:
     case ELF::R_AARCH64_MOVW_UABS_G1:
     case ELF::R_AARCH64_MOVW_UABS_G1_NC:
     case ELF::R_AARCH64_MOVW_UABS_G2:
     case ELF::R_AARCH64_MOVW_UABS_G2_NC:
     case ELF::R_AARCH64_MOVW_UABS_G3:
+    case ELF::R_AARCH64_PREL16:
+    case ELF::R_AARCH64_PREL32:
+    case ELF::R_AARCH64_PREL64:
       Rels[Offset] = Relocation{Offset, Symbol, RelType, Addend, Value};
       return;
     case ELF::R_AARCH64_CALL26:
     case ELF::R_AARCH64_JUMP26:
     case ELF::R_AARCH64_TSTBR14:
     case ELF::R_AARCH64_CONDBR19:
     case ELF::R_AARCH64_TLSDESC_CALL:
     case ELF::R_AARCH64_TLSLE_ADD_TPREL_HI12:

bolt/lib/Core/Relocation.cpp

bool isSupportedAArch64(uint64_t Type) {
   case ELF::R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC:
   case ELF::R_AARCH64_TLSLE_ADD_TPREL_HI12:
   case ELF::R_AARCH64_TLSLE_ADD_TPREL_LO12_NC:
   case ELF::R_AARCH64_LD64_GOT_LO12_NC:
   case ELF::R_AARCH64_TLSDESC_LD64_LO12:
   case ELF::R_AARCH64_TLSDESC_ADD_LO12:
   case ELF::R_AARCH64_TLSDESC_CALL:
   case ELF::R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
+  case ELF::R_AARCH64_PREL16:
   case ELF::R_AARCH64_PREL32:
+  case ELF::R_AARCH64_PREL64:
   case ELF::R_AARCH64_ABS16:
   case ELF::R_AARCH64_ABS32:
   case ELF::R_AARCH64_ABS64:
   case ELF::R_AARCH64_MOVW_UABS_G0:
   case ELF::R_AARCH64_MOVW_UABS_G0_NC:
   case ELF::R_AARCH64_MOVW_UABS_G1:
   case ELF::R_AARCH64_MOVW_UABS_G1_NC:
   case ELF::R_AARCH64_MOVW_UABS_G2:

 }
 
 size_t getSizeForTypeAArch64(uint64_t Type) {
   switch (Type) {
   default:
     errs() << object::getELFRelocationTypeName(ELF::EM_AARCH64, Type) << '\n';
     llvm_unreachable("unsupported relocation type");
   case ELF::R_AARCH64_ABS16:
+  case ELF::R_AARCH64_PREL16:
     return 2;
   case ELF::R_AARCH64_CALL26:
   case ELF::R_AARCH64_JUMP26:
   case ELF::R_AARCH64_TSTBR14:
   case ELF::R_AARCH64_CONDBR19:
   case ELF::R_AARCH64_ADR_PREL_LO21:
   case ELF::R_AARCH64_ADR_PREL_PG_HI21:
   case ELF::R_AARCH64_ADR_PREL_PG_HI21_NC:
size_t getSizeForTypeAArch64(uint64_t Type) {
   case ELF::R_AARCH64_MOVW_UABS_G1:
   case ELF::R_AARCH64_MOVW_UABS_G1_NC:
   case ELF::R_AARCH64_MOVW_UABS_G2:
   case ELF::R_AARCH64_MOVW_UABS_G2_NC:
   case ELF::R_AARCH64_MOVW_UABS_G3:
   case ELF::R_AARCH64_ABS32:
     return 4;
   case ELF::R_AARCH64_ABS64:
+  case ELF::R_AARCH64_PREL64:
     return 8;
   }
 }
 
 bool skipRelocationProcessX86(uint64_t Type, uint64_t Contents) {
   return false;
 }
 

 }
 
 uint64_t adjustValueAArch64(uint64_t Type, uint64_t Value, uint64_t PC) {
   switch (Type) {
   default:
     llvm_unreachable("not supported relocation");
   case ELF::R_AARCH64_ABS32:
     break;
+  case ELF::R_AARCH64_PREL16:
   case ELF::R_AARCH64_PREL32:
+  case ELF::R_AARCH64_PREL64:
     Value -= PC;
     break;
   }
   return Value;
 }
 
 uint64_t extractValueX86(uint64_t Type, uint64_t Contents, uint64_t PC) {
   if (Type == ELF::R_X86_64_32S)
     return SignExtend64<32>(Contents);
   if (Relocation::isPCRelative(Type))
     return SignExtend64(Contents, 8 * Relocation::getSizeForType(Type));
   return Contents;
 }
 
 uint64_t extractValueAArch64(uint64_t Type, uint64_t Contents, uint64_t PC) {
   switch (Type) {
   default:
     errs() << object::getELFRelocationTypeName(ELF::EM_AARCH64, Type) << '\n';
     llvm_unreachable("unsupported relocation type");
   case ELF::R_AARCH64_ABS16:
   case ELF::R_AARCH64_ABS32:
   case ELF::R_AARCH64_ABS64:
     return Contents;
+  case ELF::R_AARCH64_PREL16:
+    return static_cast<int64_t>(PC) + SignExtend64<16>(Contents & 0xffff);
   case ELF::R_AARCH64_PREL32:
     return static_cast<int64_t>(PC) + SignExtend64<32>(Contents & 0xffffffff);
+  case ELF::R_AARCH64_PREL64:
+    return static_cast<int64_t>(PC) + Contents;
   case ELF::R_AARCH64_TLSDESC_CALL:
   case ELF::R_AARCH64_JUMP26:
   case ELF::R_AARCH64_CALL26:
     // Immediate goes in bits 25:0 of B and BL.
     Contents &= ~0xfffffffffc000000ULL;
     return static_cast<int64_t>(PC) + SignExtend64<28>(Contents << 2);
   case ELF::R_AARCH64_TSTBR14:
     // Immediate:15:2 goes in bits 18:5 of TBZ, TBNZ
bool isPCRelativeAArch64(uint64_t Type) {
   case ELF::R_AARCH64_CONDBR19:
   case ELF::R_AARCH64_ADR_PREL_LO21:
   case ELF::R_AARCH64_ADR_PREL_PG_HI21:
   case ELF::R_AARCH64_ADR_PREL_PG_HI21_NC:
   case ELF::R_AARCH64_ADR_GOT_PAGE:
   case ELF::R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21:
   case ELF::R_AARCH64_TLSDESC_ADR_PREL21:
   case ELF::R_AARCH64_TLSDESC_ADR_PAGE21:
+  case ELF::R_AARCH64_PREL16:
   case ELF::R_AARCH64_PREL32:
+  case ELF::R_AARCH64_PREL64:
     return true;
   }
 }
 
 } // end anonymous namespace
 
 bool Relocation::isSupported(uint64_t Type) {
   if (Arch == Triple::aarch64)

bolt/test/lit.cfg.py

tools = [
     ToolSubst('llvm-mc', unresolved='fatal'),
     ToolSubst('llvm-nm', unresolved='fatal'),
     ToolSubst('llvm-objdump', unresolved='fatal'),
     ToolSubst('llvm-objcopy', unresolved='fatal'),
     ToolSubst('llvm-strip', unresolved='fatal'),
     ToolSubst('llvm-readelf', unresolved='fatal'),
     ToolSubst('link_fdata', command=link_fdata_cmd, unresolved='fatal'),
     ToolSubst('merge-fdata', unresolved='fatal'),
+    ToolSubst('llvm-readobj', unresolved='fatal'),
 ]
 llvm_config.add_tool_substitutions(tools, tool_dirs)
 
 def calculate_arch_features(arch_string):
     features = []
     for arch in arch_string.split():
         features.append(arch.lower() + '-registered-target')
     return features
 
 
 llvm_config.feature_config(
     [('--assertion-mode', {'ON': 'asserts'}),
      ('--cxxflags', {r'-D_GLIBCXX_DEBUG\b': 'libstdcxx-safe-mode'}),
         ('--targets-built', calculate_arch_features)
      ])

bolt/test/runtime/AArch64/r_aarch64_prelxx.s

+// This test checks processing of R_AARCH64_PREL64/32/16 relocations
+
+// RUN: %clang %cflags -nostartfiles -nostdlib %s -o %t.exe -Wl,-q \
+// RUN:     -Wl,-z,max-page-size=4
+// RUN: llvm-readelf -Wa %t.exe | FileCheck %s -check-prefix=CHECKPREL
+
+// CHECKPREL:       R_AARCH64_PREL16      {{.*}} .dummy + 0
+// CHECKPREL-NEXT:  R_AARCH64_PREL32      {{.*}} _start + 4
+// CHECKPREL-NEXT:  R_AARCH64_PREL64      {{.*}} _start + 8
+
+// RUN: llvm-bolt %t.exe -o %t.bolt
+// RUN: llvm-readobj -S --section-data %t.bolt | FileCheck %s
+
+// CHECK: Name: .data
+// CHECK: SectionData (
+// CHECK:   0000: FCFF0000 44FF3F00 44FF3F00 00000000
+// CHECK: )
+
+  .text
+  .align 4
+  .globl _start
+  .type _start, %function
+_start:
+  adr x0, datatable
+  mov x0, #0
+  ret 
+
+.section .dummy, "da"
+dummy:
+  .word 0
+
+.section .data
+datatable:
+  .hword dummy - datatable
+  .align 2
+  .word _start - datatable
+  .xword _start - datatable

llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

case ELF::R_AARCH64_ABS64:
     break;
   case ELF::R_AARCH64_PLT32: {
     uint64_t Result = Value + Addend - FinalAddress;
     assert(static_cast<int64_t>(Result) >= INT32_MIN &&
            static_cast<int64_t>(Result) <= INT32_MAX);
     write(isBE, TargetPtr, static_cast<uint32_t>(Result));
     break;
   }
+  case ELF::R_AARCH64_PREL16: {
+    uint64_t Result = Value + Addend - FinalAddress;
+    assert(static_cast<int64_t>(Result) >= INT16_MIN &&
+           static_cast<int64_t>(Result) <= UINT16_MAX);
+    write(isBE, TargetPtr, static_cast<uint16_t>(Result & 0xffffU));
+    break;
+  }
   case ELF::R_AARCH64_PREL32: {
     uint64_t Result = Value + Addend - FinalAddress;
     assert(static_cast<int64_t>(Result) >= INT32_MIN &&
            static_cast<int64_t>(Result) <= UINT32_MAX);
     write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
     break;
   }
   case ELF::R_AARCH64_PREL64:

llvm/lib/Object/RelocationResolver.cpp

default:
     llvm_unreachable("Invalid relocation type");
   }
 }
 
 static bool supportsAArch64(uint64_t Type) {
   switch (Type) {
   case ELF::R_AARCH64_ABS32:
   case ELF::R_AARCH64_ABS64:
+  case ELF::R_AARCH64_PREL16:
   case ELF::R_AARCH64_PREL32:
   case ELF::R_AARCH64_PREL64:
     return true;
   default:
     return false;
   }
 }
 
 static uint64_t resolveAArch64(uint64_t Type, uint64_t Offset, uint64_t S,
                                uint64_t /*LocData*/, int64_t Addend) {
   switch (Type) {
   case ELF::R_AARCH64_ABS32:
     return (S + Addend) & 0xFFFFFFFF;
   case ELF::R_AARCH64_ABS64:
     return S + Addend;
+  case ELF::R_AARCH64_PREL16:
+    return (S + Addend - Offset) & 0xFFFF;
   case ELF::R_AARCH64_PREL32:
     return (S + Addend - Offset) & 0xFFFFFFFF;
   case ELF::R_AARCH64_PREL64:
     return S + Addend - Offset;
   default:
     llvm_unreachable("Invalid relocation type");
   }
 }