1//===- ARM64.cpp ----------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "Arch/ARM64Common.h"
10#include "InputFiles.h"
11#include "Symbols.h"
12#include "SyntheticSections.h"
13#include "Target.h"
14
15#include "lld/Common/ErrorHandler.h"
16#include "llvm/ADT/SmallVector.h"
17#include "llvm/ADT/StringRef.h"
18#include "llvm/BinaryFormat/MachO.h"
19#include "llvm/Support/Endian.h"
20#include "llvm/Support/MathExtras.h"
21
22using namespace llvm::MachO;
23using namespace llvm::support::endian;
24using namespace lld;
25using namespace lld::macho;
26
27namespace {
28
29struct ARM64 : ARM64Common {
30 ARM64();
31 void writeStub(uint8_t *buf, const Symbol &) const override;
32 void writeStubHelperHeader(uint8_t *buf) const override;
33 void writeStubHelperEntry(uint8_t *buf, const DylibSymbol &,
34 uint64_t entryAddr) const override;
35 const RelocAttrs &getRelocAttrs(uint8_t type) const override;
36};
37
38} // namespace
39
40// Random notes on reloc types:
41// ADDEND always pairs with BRANCH26, PAGE21, or PAGEOFF12
42// POINTER_TO_GOT: ld64 supports a 4-byte pc-relative form as well as an 8-byte
43// absolute version of this relocation. The semantics of the absolute relocation
44// are weird -- it results in the value of the GOT slot being written, instead
45// of the address. Let's not support it unless we find a real-world use case.
46
47const RelocAttrs &ARM64::getRelocAttrs(uint8_t type) const {
48 static const std::array<RelocAttrs, 11> relocAttrsArray{{
49#define B(x) RelocAttrBits::x
50 {"UNSIGNED",
51 B(UNSIGNED) | B(ABSOLUTE) | B(EXTERN) | B(LOCAL) | B(BYTE4) | B(BYTE8)},
52 {"SUBTRACTOR", B(SUBTRAHEND) | B(EXTERN) | B(BYTE4) | B(BYTE8)},
53 {"BRANCH26", B(PCREL) | B(EXTERN) | B(BRANCH) | B(BYTE4)},
54 {"PAGE21", B(PCREL) | B(EXTERN) | B(BYTE4)},
55 {"PAGEOFF12", B(ABSOLUTE) | B(EXTERN) | B(BYTE4)},
56 {"GOT_LOAD_PAGE21", B(PCREL) | B(EXTERN) | B(GOT) | B(BYTE4)},
57 {"GOT_LOAD_PAGEOFF12",
58 B(ABSOLUTE) | B(EXTERN) | B(GOT) | B(LOAD) | B(BYTE4)},
59 {"POINTER_TO_GOT", B(PCREL) | B(EXTERN) | B(GOT) | B(POINTER) | B(BYTE4)},
60 {"TLVP_LOAD_PAGE21", B(PCREL) | B(EXTERN) | B(TLV) | B(BYTE4)},
61 {"TLVP_LOAD_PAGEOFF12",
62 B(ABSOLUTE) | B(EXTERN) | B(TLV) | B(LOAD) | B(BYTE4)},
63 {"ADDEND", B(ADDEND)},
64#undef B
65 }};
66 assert(type < relocAttrsArray.size() && "invalid relocation type");
67 if (type >= relocAttrsArray.size())
68 return invalidRelocAttrs;
69 return relocAttrsArray[type];
70}
71
72static constexpr uint32_t stubCode[] = {
73 0x90000010, // 00: adrp x16, __la_symbol_ptr@page
74 0xf9400210, // 04: ldr x16, [x16, __la_symbol_ptr@pageoff]
75 0xd61f0200, // 08: br x16
76};
77
78void ARM64::writeStub(uint8_t *buf8, const Symbol &sym) const {
79 ::writeStub<LP64>(buf8, stubCode, sym);
80}
81
82static constexpr uint32_t stubHelperHeaderCode[] = {
83 0x90000011, // 00: adrp x17, _dyld_private@page
84 0x91000231, // 04: add x17, x17, _dyld_private@pageoff
85 0xa9bf47f0, // 08: stp x16/x17, [sp, #-16]!
86 0x90000010, // 0c: adrp x16, dyld_stub_binder@page
87 0xf9400210, // 10: ldr x16, [x16, dyld_stub_binder@pageoff]
88 0xd61f0200, // 14: br x16
89};
90
91void ARM64::writeStubHelperHeader(uint8_t *buf8) const {
92 ::writeStubHelperHeader<LP64>(buf8, stubHelperHeaderCode);
93}
94
95static constexpr uint32_t stubHelperEntryCode[] = {
96 0x18000050, // 00: ldr w16, l0
97 0x14000000, // 04: b stubHelperHeader
98 0x00000000, // 08: l0: .long 0
99};
100
101void ARM64::writeStubHelperEntry(uint8_t *buf8, const DylibSymbol &sym,
102 uint64_t entryVA) const {
103 ::writeStubHelperEntry(buf8, stubHelperEntryCode, sym, entryVA);
104}
105
106ARM64::ARM64() : ARM64Common(LP64()) {
107 cpuType = CPU_TYPE_ARM64;
108 cpuSubtype = CPU_SUBTYPE_ARM64_ALL;
109
110 stubSize = sizeof(stubCode);
111 stubHelperHeaderSize = sizeof(stubHelperHeaderCode);
112 stubHelperEntrySize = sizeof(stubHelperEntryCode);
113}
114
115TargetInfo *macho::createARM64TargetInfo() {
116 static ARM64 t;
117 return &t;
118}
119