lld/MachO/Arch/ARM64_32.cpp

   1 //===- ARM64_32.cpp
   2 //----------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "Arch/ARM64Common.h"
  11 #include "InputFiles.h"
  12 #include "Symbols.h"
  13 #include "SyntheticSections.h"
  14 #include "Target.h"
  15
  16 #include "lld/Common/ErrorHandler.h"
  17 #include "llvm/ADT/SmallVector.h"
  18 #include "llvm/ADT/StringRef.h"
  19 #include "llvm/BinaryFormat/MachO.h"
  20 #include "llvm/Support/Endian.h"
  21 #include "llvm/Support/MathExtras.h"
  22
  23 using namespace llvm::MachO;
  24 using namespace llvm::support::endian;
  25 using namespace lld;
  26 using namespace lld::macho;
  27
  28 namespace {
  29
  30 struct ARM64_32 : ARM64Common {
  31   ARM64_32();
  32   void writeStub(uint8_t *buf, const Symbol &) const override;
  33   void writeStubHelperHeader(uint8_t *buf) const override;
  34   void writeStubHelperEntry(uint8_t *buf, const Symbol &,
  35                             uint64_t entryAddr) const override;
  36 };
  37
  38 } // namespace
  39
  40 // These are very similar to ARM64's relocation attributes, except that we don't
  41 // have the BYTE8 flag set.
  42 static constexpr std::array<RelocAttrs, 11> relocAttrsArray{{
  43 #define B(x) RelocAttrBits::x
  44     {"UNSIGNED", B(UNSIGNED) | B(ABSOLUTE) | B(EXTERN) | B(LOCAL) | B(BYTE4)},
  45     {"SUBTRACTOR", B(SUBTRAHEND) | B(EXTERN) | B(BYTE4)},
  46     {"BRANCH26", B(PCREL) | B(EXTERN) | B(BRANCH) | B(BYTE4)},
  47     {"PAGE21", B(PCREL) | B(EXTERN) | B(BYTE4)},
  48     {"PAGEOFF12", B(ABSOLUTE) | B(EXTERN) | B(BYTE4)},
  49     {"GOT_LOAD_PAGE21", B(PCREL) | B(EXTERN) | B(GOT) | B(BYTE4)},
  50     {"GOT_LOAD_PAGEOFF12",
  51      B(ABSOLUTE) | B(EXTERN) | B(GOT) | B(LOAD) | B(BYTE4)},
  52     {"POINTER_TO_GOT", B(PCREL) | B(EXTERN) | B(GOT) | B(POINTER) | B(BYTE4)},
  53     {"TLVP_LOAD_PAGE21", B(PCREL) | B(EXTERN) | B(TLV) | B(BYTE4)},
  54     {"TLVP_LOAD_PAGEOFF12",
  55      B(ABSOLUTE) | B(EXTERN) | B(TLV) | B(LOAD) | B(BYTE4)},
  56     {"ADDEND", B(ADDEND)},
  57 #undef B
  58 }};
  59
  60 // The stub code is fairly similar to ARM64's, except that we load pointers into
  61 // 32-bit 'w' registers, instead of the 64-bit 'x' ones.
  62
  63 static constexpr uint32_t stubCode[] = {
  64     0x90000010, // 00: adrp  x16, __la_symbol_ptr@page
  65     0xb9400210, // 04: ldr   w16, [x16, __la_symbol_ptr@pageoff]
  66     0xd61f0200, // 08: br    x16
  67 };
  68
  69 void ARM64_32::writeStub(uint8_t *buf8, const Symbol &sym) const {
  70   ::writeStub<ILP32>(buf8, stubCode, sym);
  71 }
  72
  73 static constexpr uint32_t stubHelperHeaderCode[] = {
  74     0x90000011, // 00: adrp  x17, _dyld_private@page
  75     0x91000231, // 04: add   x17, x17, _dyld_private@pageoff
  76     0xa9bf47f0, // 08: stp   x16/x17, [sp, #-16]!
  77     0x90000010, // 0c: adrp  x16, dyld_stub_binder@page
  78     0xb9400210, // 10: ldr   w16, [x16, dyld_stub_binder@pageoff]
  79     0xd61f0200, // 14: br    x16
  80 };
  81
  82 void ARM64_32::writeStubHelperHeader(uint8_t *buf8) const {
  83   ::writeStubHelperHeader<ILP32>(buf8, stubHelperHeaderCode);
  84 }
  85
  86 static constexpr uint32_t stubHelperEntryCode[] = {
  87     0x18000050, // 00: ldr  w16, l0
  88     0x14000000, // 04: b    stubHelperHeader
  89     0x00000000, // 08: l0: .long 0
  90 };
  91
  92 void ARM64_32::writeStubHelperEntry(uint8_t *buf8, const Symbol &sym,
  93                                     uint64_t entryVA) const {
  94   ::writeStubHelperEntry(buf8, stubHelperEntryCode, sym, entryVA);
  95 }
  96
  97 ARM64_32::ARM64_32() : ARM64Common(ILP32()) {
  98   cpuType = CPU_TYPE_ARM64_32;
  99   cpuSubtype = CPU_SUBTYPE_ARM64_V8;
 100
 101   modeDwarfEncoding = 0x04000000;              // UNWIND_ARM_MODE_DWARF
 102   subtractorRelocType = GENERIC_RELOC_INVALID; // FIXME
 103   unsignedRelocType = GENERIC_RELOC_INVALID;   // FIXME
 104
 105   stubSize = sizeof(stubCode);
 106   stubHelperHeaderSize = sizeof(stubHelperHeaderCode);
 107   stubHelperEntrySize = sizeof(stubHelperEntryCode);
 108
 109   relocAttrs = {relocAttrsArray.data(), relocAttrsArray.size()};
 110 }
 111
 112 TargetInfo *macho::createARM64_32TargetInfo() {
 113   static ARM64_32 t;
 114   return &t;
 115 }