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//===- ARM64.cpp ----------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "Arch/ARM64Common.h"
#include "InputFiles.h"
#include "Symbols.h"
#include "SyntheticSections.h"
#include "Target.h"
#include "lld/Common/ErrorHandler.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
using namespace llvm::MachO;
using namespace llvm::support::endian;
using namespace lld;
using namespace lld::macho;
namespace {
struct ARM64 : ARM64Common {
ARM64();
void writeStub(uint8_t *buf, const Symbol &) const override;
void writeStubHelperHeader(uint8_t *buf) const override;
void writeStubHelperEntry(uint8_t *buf, const DylibSymbol &,
uint64_t entryAddr) const override;
const RelocAttrs &getRelocAttrs(uint8_t type) const override;
void populateThunk(InputSection *thunk, Symbol *funcSym) override;
};
} // namespace
// Random notes on reloc types:
// ADDEND always pairs with BRANCH26, PAGE21, or PAGEOFF12
// POINTER_TO_GOT: ld64 supports a 4-byte pc-relative form as well as an 8-byte
// absolute version of this relocation. The semantics of the absolute relocation
// are weird -- it results in the value of the GOT slot being written, instead
// of the address. Let's not support it unless we find a real-world use case.
const RelocAttrs &ARM64::getRelocAttrs(uint8_t type) const {
static const std::array<RelocAttrs, 11> relocAttrsArray{{
#define B(x) RelocAttrBits::x
{"UNSIGNED",
B(UNSIGNED) | B(ABSOLUTE) | B(EXTERN) | B(LOCAL) | B(BYTE4) | B(BYTE8)},
{"SUBTRACTOR", B(SUBTRAHEND) | B(EXTERN) | B(BYTE4) | B(BYTE8)},
{"BRANCH26", B(PCREL) | B(EXTERN) | B(BRANCH) | B(BYTE4)},
{"PAGE21", B(PCREL) | B(EXTERN) | B(BYTE4)},
{"PAGEOFF12", B(ABSOLUTE) | B(EXTERN) | B(BYTE4)},
{"GOT_LOAD_PAGE21", B(PCREL) | B(EXTERN) | B(GOT) | B(BYTE4)},
{"GOT_LOAD_PAGEOFF12",
B(ABSOLUTE) | B(EXTERN) | B(GOT) | B(LOAD) | B(BYTE4)},
{"POINTER_TO_GOT", B(PCREL) | B(EXTERN) | B(GOT) | B(POINTER) | B(BYTE4)},
{"TLVP_LOAD_PAGE21", B(PCREL) | B(EXTERN) | B(TLV) | B(BYTE4)},
{"TLVP_LOAD_PAGEOFF12",
B(ABSOLUTE) | B(EXTERN) | B(TLV) | B(LOAD) | B(BYTE4)},
{"ADDEND", B(ADDEND)},
#undef B
}};
assert(type < relocAttrsArray.size() && "invalid relocation type");
if (type >= relocAttrsArray.size())
return invalidRelocAttrs;
return relocAttrsArray[type];
}
static constexpr uint32_t stubCode[] = {
0x90000010, // 00: adrp x16, __la_symbol_ptr@page
0xf9400210, // 04: ldr x16, [x16, __la_symbol_ptr@pageoff]
0xd61f0200, // 08: br x16
};
void ARM64::writeStub(uint8_t *buf8, const Symbol &sym) const {
::writeStub<LP64>(buf8, stubCode, sym);
}
static constexpr uint32_t stubHelperHeaderCode[] = {
0x90000011, // 00: adrp x17, _dyld_private@page
0x91000231, // 04: add x17, x17, _dyld_private@pageoff
0xa9bf47f0, // 08: stp x16/x17, [sp, #-16]!
0x90000010, // 0c: adrp x16, dyld_stub_binder@page
0xf9400210, // 10: ldr x16, [x16, dyld_stub_binder@pageoff]
0xd61f0200, // 14: br x16
};
void ARM64::writeStubHelperHeader(uint8_t *buf8) const {
::writeStubHelperHeader<LP64>(buf8, stubHelperHeaderCode);
}
static constexpr uint32_t stubHelperEntryCode[] = {
0x18000050, // 00: ldr w16, l0
0x14000000, // 04: b stubHelperHeader
0x00000000, // 08: l0: .long 0
};
void ARM64::writeStubHelperEntry(uint8_t *buf8, const DylibSymbol &sym,
uint64_t entryVA) const {
::writeStubHelperEntry(buf8, stubHelperEntryCode, sym, entryVA);
}
// A thunk is the relaxed variation of stubCode. We don't need the
// extra indirection through a lazy pointer because the target address
// is known at link time.
static constexpr uint32_t thunkCode[] = {
0x90000010, // 00: adrp x16, <thunk.ptr>@page
0x91000210, // 04: add x16, [x16,<thunk.ptr>@pageoff]
0xd61f0200, // 08: br x16
};
void ARM64::populateThunk(InputSection *thunk, Symbol *funcSym) {
thunk->align = 4;
thunk->data = {reinterpret_cast<const uint8_t *>(thunkCode),
sizeof(thunkCode)};
thunk->relocs.push_back({/*type=*/ARM64_RELOC_PAGEOFF12,
/*pcrel=*/false, /*length=*/2,
/*offset=*/4, /*addend=*/0,
/*referent=*/funcSym});
thunk->relocs.push_back({/*type=*/ARM64_RELOC_PAGE21,
/*pcrel=*/true, /*length=*/2,
/*offset=*/0, /*addend=*/0,
/*referent=*/funcSym});
}
ARM64::ARM64() : ARM64Common(LP64()) {
cpuType = CPU_TYPE_ARM64;
cpuSubtype = CPU_SUBTYPE_ARM64_ALL;
stubSize = sizeof(stubCode);
thunkSize = sizeof(thunkCode);
branchRange = maxIntN(28) - thunkSize;
stubHelperHeaderSize = sizeof(stubHelperHeaderCode);
stubHelperEntrySize = sizeof(stubHelperEntryCode);
}
TargetInfo *macho::createARM64TargetInfo() {
static ARM64 t;
return &t;
}
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