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Diffstat (limited to 'ELF/SyntheticSections.cpp')
| -rw-r--r-- | ELF/SyntheticSections.cpp | 1990 |
1 files changed, 1990 insertions, 0 deletions
diff --git a/ELF/SyntheticSections.cpp b/ELF/SyntheticSections.cpp new file mode 100644 index 000000000000..3c8a439ba308 --- /dev/null +++ b/ELF/SyntheticSections.cpp @@ -0,0 +1,1990 @@ +//===- SyntheticSections.cpp ----------------------------------------------===// +// +// The LLVM Linker +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains linker-synthesized sections. Currently, +// synthetic sections are created either output sections or input sections, +// but we are rewriting code so that all synthetic sections are created as +// input sections. +// +//===----------------------------------------------------------------------===// + +#include "SyntheticSections.h" +#include "Config.h" +#include "Error.h" +#include "InputFiles.h" +#include "LinkerScript.h" +#include "Memory.h" +#include "OutputSections.h" +#include "Strings.h" +#include "SymbolTable.h" +#include "Target.h" +#include "Threads.h" +#include "Writer.h" +#include "lld/Config/Version.h" +#include "llvm/Support/Dwarf.h" +#include "llvm/Support/Endian.h" +#include "llvm/Support/MD5.h" +#include "llvm/Support/RandomNumberGenerator.h" +#include "llvm/Support/SHA1.h" +#include "llvm/Support/xxhash.h" +#include <cstdlib> + +using namespace llvm; +using namespace llvm::dwarf; +using namespace llvm::ELF; +using namespace llvm::object; +using namespace llvm::support; +using namespace llvm::support::endian; + +using namespace lld; +using namespace lld::elf; + +template <class ELFT> static std::vector<DefinedCommon *> getCommonSymbols() { + std::vector<DefinedCommon *> V; + for (Symbol *S : Symtab<ELFT>::X->getSymbols()) + if (auto *B = dyn_cast<DefinedCommon>(S->body())) + V.push_back(B); + return V; +} + +// Find all common symbols and allocate space for them. +template <class ELFT> InputSection<ELFT> *elf::createCommonSection() { + auto *Ret = make<InputSection<ELFT>>(SHF_ALLOC | SHF_WRITE, SHT_NOBITS, 1, + ArrayRef<uint8_t>(), "COMMON"); + Ret->Live = true; + + // Sort the common symbols by alignment as an heuristic to pack them better. + std::vector<DefinedCommon *> Syms = getCommonSymbols<ELFT>(); + std::stable_sort(Syms.begin(), Syms.end(), + [](const DefinedCommon *A, const DefinedCommon *B) { + return A->Alignment > B->Alignment; + }); + + // Assign offsets to symbols. + size_t Size = 0; + size_t Alignment = 1; + for (DefinedCommon *Sym : Syms) { + Alignment = std::max<size_t>(Alignment, Sym->Alignment); + Size = alignTo(Size, Sym->Alignment); + + // Compute symbol offset relative to beginning of input section. + Sym->Offset = Size; + Size += Sym->Size; + } + Ret->Alignment = Alignment; + Ret->Data = makeArrayRef<uint8_t>(nullptr, Size); + return Ret; +} + +// Returns an LLD version string. +static ArrayRef<uint8_t> getVersion() { + // Check LLD_VERSION first for ease of testing. + // You can get consitent output by using the environment variable. + // This is only for testing. + StringRef S = getenv("LLD_VERSION"); + if (S.empty()) + S = Saver.save(Twine("Linker: ") + getLLDVersion()); + + // +1 to include the terminating '\0'. + return {(const uint8_t *)S.data(), S.size() + 1}; +} + +// Creates a .comment section containing LLD version info. +// With this feature, you can identify LLD-generated binaries easily +// by "objdump -s -j .comment <file>". +// The returned object is a mergeable string section. +template <class ELFT> MergeInputSection<ELFT> *elf::createCommentSection() { + typename ELFT::Shdr Hdr = {}; + Hdr.sh_flags = SHF_MERGE | SHF_STRINGS; + Hdr.sh_type = SHT_PROGBITS; + Hdr.sh_entsize = 1; + Hdr.sh_addralign = 1; + + auto *Ret = make<MergeInputSection<ELFT>>(/*file=*/nullptr, &Hdr, ".comment"); + Ret->Data = getVersion(); + Ret->splitIntoPieces(); + return Ret; +} + +// .MIPS.abiflags section. +template <class ELFT> +MipsAbiFlagsSection<ELFT>::MipsAbiFlagsSection(Elf_Mips_ABIFlags Flags) + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_ABIFLAGS, 8, ".MIPS.abiflags"), + Flags(Flags) {} + +template <class ELFT> void MipsAbiFlagsSection<ELFT>::writeTo(uint8_t *Buf) { + memcpy(Buf, &Flags, sizeof(Flags)); +} + +template <class ELFT> +MipsAbiFlagsSection<ELFT> *MipsAbiFlagsSection<ELFT>::create() { + Elf_Mips_ABIFlags Flags = {}; + bool Create = false; + + for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) { + if (!Sec->Live || Sec->Type != SHT_MIPS_ABIFLAGS) + continue; + Sec->Live = false; + Create = true; + + std::string Filename = toString(Sec->getFile()); + const size_t Size = Sec->Data.size(); + // Older version of BFD (such as the default FreeBSD linker) concatenate + // .MIPS.abiflags instead of merging. To allow for this case (or potential + // zero padding) we ignore everything after the first Elf_Mips_ABIFlags + if (Size < sizeof(Elf_Mips_ABIFlags)) { + error(Filename + ": invalid size of .MIPS.abiflags section: got " + + Twine(Size) + " instead of " + Twine(sizeof(Elf_Mips_ABIFlags))); + return nullptr; + } + auto *S = reinterpret_cast<const Elf_Mips_ABIFlags *>(Sec->Data.data()); + if (S->version != 0) { + error(Filename + ": unexpected .MIPS.abiflags version " + + Twine(S->version)); + return nullptr; + } + + // LLD checks ISA compatibility in getMipsEFlags(). Here we just + // select the highest number of ISA/Rev/Ext. + Flags.isa_level = std::max(Flags.isa_level, S->isa_level); + Flags.isa_rev = std::max(Flags.isa_rev, S->isa_rev); + Flags.isa_ext = std::max(Flags.isa_ext, S->isa_ext); + Flags.gpr_size = std::max(Flags.gpr_size, S->gpr_size); + Flags.cpr1_size = std::max(Flags.cpr1_size, S->cpr1_size); + Flags.cpr2_size = std::max(Flags.cpr2_size, S->cpr2_size); + Flags.ases |= S->ases; + Flags.flags1 |= S->flags1; + Flags.flags2 |= S->flags2; + Flags.fp_abi = elf::getMipsFpAbiFlag(Flags.fp_abi, S->fp_abi, Filename); + }; + + if (Create) + return make<MipsAbiFlagsSection<ELFT>>(Flags); + return nullptr; +} + +// .MIPS.options section. +template <class ELFT> +MipsOptionsSection<ELFT>::MipsOptionsSection(Elf_Mips_RegInfo Reginfo) + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_OPTIONS, 8, ".MIPS.options"), + Reginfo(Reginfo) {} + +template <class ELFT> void MipsOptionsSection<ELFT>::writeTo(uint8_t *Buf) { + auto *Options = reinterpret_cast<Elf_Mips_Options *>(Buf); + Options->kind = ODK_REGINFO; + Options->size = getSize(); + + if (!Config->Relocatable) + Reginfo.ri_gp_value = In<ELFT>::MipsGot->getGp(); + memcpy(Buf + sizeof(Elf_Mips_Options), &Reginfo, sizeof(Reginfo)); +} + +template <class ELFT> +MipsOptionsSection<ELFT> *MipsOptionsSection<ELFT>::create() { + // N64 ABI only. + if (!ELFT::Is64Bits) + return nullptr; + + Elf_Mips_RegInfo Reginfo = {}; + bool Create = false; + + for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) { + if (!Sec->Live || Sec->Type != SHT_MIPS_OPTIONS) + continue; + Sec->Live = false; + Create = true; + + std::string Filename = toString(Sec->getFile()); + ArrayRef<uint8_t> D = Sec->Data; + + while (!D.empty()) { + if (D.size() < sizeof(Elf_Mips_Options)) { + error(Filename + ": invalid size of .MIPS.options section"); + break; + } + + auto *Opt = reinterpret_cast<const Elf_Mips_Options *>(D.data()); + if (Opt->kind == ODK_REGINFO) { + if (Config->Relocatable && Opt->getRegInfo().ri_gp_value) + error(Filename + ": unsupported non-zero ri_gp_value"); + Reginfo.ri_gprmask |= Opt->getRegInfo().ri_gprmask; + Sec->getFile()->MipsGp0 = Opt->getRegInfo().ri_gp_value; + break; + } + + if (!Opt->size) + fatal(Filename + ": zero option descriptor size"); + D = D.slice(Opt->size); + } + }; + + if (Create) + return make<MipsOptionsSection<ELFT>>(Reginfo); + return nullptr; +} + +// MIPS .reginfo section. +template <class ELFT> +MipsReginfoSection<ELFT>::MipsReginfoSection(Elf_Mips_RegInfo Reginfo) + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_MIPS_REGINFO, 4, ".reginfo"), + Reginfo(Reginfo) {} + +template <class ELFT> void MipsReginfoSection<ELFT>::writeTo(uint8_t *Buf) { + if (!Config->Relocatable) + Reginfo.ri_gp_value = In<ELFT>::MipsGot->getGp(); + memcpy(Buf, &Reginfo, sizeof(Reginfo)); +} + +template <class ELFT> +MipsReginfoSection<ELFT> *MipsReginfoSection<ELFT>::create() { + // Section should be alive for O32 and N32 ABIs only. + if (ELFT::Is64Bits) + return nullptr; + + Elf_Mips_RegInfo Reginfo = {}; + bool Create = false; + + for (InputSectionBase<ELFT> *Sec : Symtab<ELFT>::X->Sections) { + if (!Sec->Live || Sec->Type != SHT_MIPS_REGINFO) + continue; + Sec->Live = false; + Create = true; + + if (Sec->Data.size() != sizeof(Elf_Mips_RegInfo)) { + error(toString(Sec->getFile()) + ": invalid size of .reginfo section"); + return nullptr; + } + auto *R = reinterpret_cast<const Elf_Mips_RegInfo *>(Sec->Data.data()); + if (Config->Relocatable && R->ri_gp_value) + error(toString(Sec->getFile()) + ": unsupported non-zero ri_gp_value"); + + Reginfo.ri_gprmask |= R->ri_gprmask; + Sec->getFile()->MipsGp0 = R->ri_gp_value; + }; + + if (Create) + return make<MipsReginfoSection<ELFT>>(Reginfo); + return nullptr; +} + +template <class ELFT> InputSection<ELFT> *elf::createInterpSection() { + auto *Ret = make<InputSection<ELFT>>(SHF_ALLOC, SHT_PROGBITS, 1, + ArrayRef<uint8_t>(), ".interp"); + Ret->Live = true; + + // StringSaver guarantees that the returned string ends with '\0'. + StringRef S = Saver.save(Config->DynamicLinker); + Ret->Data = {(const uint8_t *)S.data(), S.size() + 1}; + return Ret; +} + +static size_t getHashSize() { + switch (Config->BuildId) { + case BuildIdKind::Fast: + return 8; + case BuildIdKind::Md5: + case BuildIdKind::Uuid: + return 16; + case BuildIdKind::Sha1: + return 20; + case BuildIdKind::Hexstring: + return Config->BuildIdVector.size(); + default: + llvm_unreachable("unknown BuildIdKind"); + } +} + +template <class ELFT> +BuildIdSection<ELFT>::BuildIdSection() + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_NOTE, 1, ".note.gnu.build-id"), + HashSize(getHashSize()) {} + +template <class ELFT> void BuildIdSection<ELFT>::writeTo(uint8_t *Buf) { + const endianness E = ELFT::TargetEndianness; + write32<E>(Buf, 4); // Name size + write32<E>(Buf + 4, HashSize); // Content size + write32<E>(Buf + 8, NT_GNU_BUILD_ID); // Type + memcpy(Buf + 12, "GNU", 4); // Name string + HashBuf = Buf + 16; +} + +// Split one uint8 array into small pieces of uint8 arrays. +static std::vector<ArrayRef<uint8_t>> split(ArrayRef<uint8_t> Arr, + size_t ChunkSize) { + std::vector<ArrayRef<uint8_t>> Ret; + while (Arr.size() > ChunkSize) { + Ret.push_back(Arr.take_front(ChunkSize)); + Arr = Arr.drop_front(ChunkSize); + } + if (!Arr.empty()) + Ret.push_back(Arr); + return Ret; +} + +// Computes a hash value of Data using a given hash function. +// In order to utilize multiple cores, we first split data into 1MB +// chunks, compute a hash for each chunk, and then compute a hash value +// of the hash values. +template <class ELFT> +void BuildIdSection<ELFT>::computeHash( + llvm::ArrayRef<uint8_t> Data, + std::function<void(uint8_t *Dest, ArrayRef<uint8_t> Arr)> HashFn) { + std::vector<ArrayRef<uint8_t>> Chunks = split(Data, 1024 * 1024); + std::vector<uint8_t> Hashes(Chunks.size() * HashSize); + + // Compute hash values. + forLoop(0, Chunks.size(), + [&](size_t I) { HashFn(Hashes.data() + I * HashSize, Chunks[I]); }); + + // Write to the final output buffer. + HashFn(HashBuf, Hashes); +} + +template <class ELFT> +void BuildIdSection<ELFT>::writeBuildId(ArrayRef<uint8_t> Buf) { + switch (Config->BuildId) { + case BuildIdKind::Fast: + computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) { + write64le(Dest, xxHash64(toStringRef(Arr))); + }); + break; + case BuildIdKind::Md5: + computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) { + memcpy(Dest, MD5::hash(Arr).data(), 16); + }); + break; + case BuildIdKind::Sha1: + computeHash(Buf, [](uint8_t *Dest, ArrayRef<uint8_t> Arr) { + memcpy(Dest, SHA1::hash(Arr).data(), 20); + }); + break; + case BuildIdKind::Uuid: + if (getRandomBytes(HashBuf, HashSize)) + error("entropy source failure"); + break; + case BuildIdKind::Hexstring: + memcpy(HashBuf, Config->BuildIdVector.data(), Config->BuildIdVector.size()); + break; + default: + llvm_unreachable("unknown BuildIdKind"); + } +} + +template <class ELFT> +GotSection<ELFT>::GotSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS, + Target->GotEntrySize, ".got") {} + +template <class ELFT> void GotSection<ELFT>::addEntry(SymbolBody &Sym) { + Sym.GotIndex = NumEntries; + ++NumEntries; +} + +template <class ELFT> bool GotSection<ELFT>::addDynTlsEntry(SymbolBody &Sym) { + if (Sym.GlobalDynIndex != -1U) + return false; + Sym.GlobalDynIndex = NumEntries; + // Global Dynamic TLS entries take two GOT slots. + NumEntries += 2; + return true; +} + +// Reserves TLS entries for a TLS module ID and a TLS block offset. +// In total it takes two GOT slots. +template <class ELFT> bool GotSection<ELFT>::addTlsIndex() { + if (TlsIndexOff != uint32_t(-1)) + return false; + TlsIndexOff = NumEntries * sizeof(uintX_t); + NumEntries += 2; + return true; +} + +template <class ELFT> +typename GotSection<ELFT>::uintX_t +GotSection<ELFT>::getGlobalDynAddr(const SymbolBody &B) const { + return this->getVA() + B.GlobalDynIndex * sizeof(uintX_t); +} + +template <class ELFT> +typename GotSection<ELFT>::uintX_t +GotSection<ELFT>::getGlobalDynOffset(const SymbolBody &B) const { + return B.GlobalDynIndex * sizeof(uintX_t); +} + +template <class ELFT> void GotSection<ELFT>::finalize() { + Size = NumEntries * sizeof(uintX_t); +} + +template <class ELFT> bool GotSection<ELFT>::empty() const { + // If we have a relocation that is relative to GOT (such as GOTOFFREL), + // we need to emit a GOT even if it's empty. + return NumEntries == 0 && !HasGotOffRel; +} + +template <class ELFT> void GotSection<ELFT>::writeTo(uint8_t *Buf) { + this->relocate(Buf, Buf + Size); +} + +template <class ELFT> +MipsGotSection<ELFT>::MipsGotSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE | SHF_MIPS_GPREL, + SHT_PROGBITS, Target->GotEntrySize, ".got") {} + +template <class ELFT> +void MipsGotSection<ELFT>::addEntry(SymbolBody &Sym, uintX_t Addend, + RelExpr Expr) { + // For "true" local symbols which can be referenced from the same module + // only compiler creates two instructions for address loading: + // + // lw $8, 0($gp) # R_MIPS_GOT16 + // addi $8, $8, 0 # R_MIPS_LO16 + // + // The first instruction loads high 16 bits of the symbol address while + // the second adds an offset. That allows to reduce number of required + // GOT entries because only one global offset table entry is necessary + // for every 64 KBytes of local data. So for local symbols we need to + // allocate number of GOT entries to hold all required "page" addresses. + // + // All global symbols (hidden and regular) considered by compiler uniformly. + // It always generates a single `lw` instruction and R_MIPS_GOT16 relocation + // to load address of the symbol. So for each such symbol we need to + // allocate dedicated GOT entry to store its address. + // + // If a symbol is preemptible we need help of dynamic linker to get its + // final address. The corresponding GOT entries are allocated in the + // "global" part of GOT. Entries for non preemptible global symbol allocated + // in the "local" part of GOT. + // + // See "Global Offset Table" in Chapter 5: + // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf + if (Expr == R_MIPS_GOT_LOCAL_PAGE) { + // At this point we do not know final symbol value so to reduce number + // of allocated GOT entries do the following trick. Save all output + // sections referenced by GOT relocations. Then later in the `finalize` + // method calculate number of "pages" required to cover all saved output + // section and allocate appropriate number of GOT entries. + PageIndexMap.insert({cast<DefinedRegular<ELFT>>(&Sym)->Section->OutSec, 0}); + return; + } + if (Sym.isTls()) { + // GOT entries created for MIPS TLS relocations behave like + // almost GOT entries from other ABIs. They go to the end + // of the global offset table. + Sym.GotIndex = TlsEntries.size(); + TlsEntries.push_back(&Sym); + return; + } + auto AddEntry = [&](SymbolBody &S, uintX_t A, GotEntries &Items) { + if (S.isInGot() && !A) + return; + size_t NewIndex = Items.size(); + if (!EntryIndexMap.insert({{&S, A}, NewIndex}).second) + return; + Items.emplace_back(&S, A); + if (!A) + S.GotIndex = NewIndex; + }; + if (Sym.isPreemptible()) { + // Ignore addends for preemptible symbols. They got single GOT entry anyway. + AddEntry(Sym, 0, GlobalEntries); + Sym.IsInGlobalMipsGot = true; + } else if (Expr == R_MIPS_GOT_OFF32) { + AddEntry(Sym, Addend, LocalEntries32); + Sym.Is32BitMipsGot = true; + } else { + // Hold local GOT entries accessed via a 16-bit index separately. + // That allows to write them in the beginning of the GOT and keep + // their indexes as less as possible to escape relocation's overflow. + AddEntry(Sym, Addend, LocalEntries); + } +} + +template <class ELFT> +bool MipsGotSection<ELFT>::addDynTlsEntry(SymbolBody &Sym) { + if (Sym.GlobalDynIndex != -1U) + return false; + Sym.GlobalDynIndex = TlsEntries.size(); + // Global Dynamic TLS entries take two GOT slots. + TlsEntries.push_back(nullptr); + TlsEntries.push_back(&Sym); + return true; +} + +// Reserves TLS entries for a TLS module ID and a TLS block offset. +// In total it takes two GOT slots. +template <class ELFT> bool MipsGotSection<ELFT>::addTlsIndex() { + if (TlsIndexOff != uint32_t(-1)) + return false; + TlsIndexOff = TlsEntries.size() * sizeof(uintX_t); + TlsEntries.push_back(nullptr); + TlsEntries.push_back(nullptr); + return true; +} + +static uint64_t getMipsPageAddr(uint64_t Addr) { + return (Addr + 0x8000) & ~0xffff; +} + +static uint64_t getMipsPageCount(uint64_t Size) { + return (Size + 0xfffe) / 0xffff + 1; +} + +template <class ELFT> +typename MipsGotSection<ELFT>::uintX_t +MipsGotSection<ELFT>::getPageEntryOffset(const SymbolBody &B, + uintX_t Addend) const { + const OutputSectionBase *OutSec = + cast<DefinedRegular<ELFT>>(&B)->Section->OutSec; + uintX_t SecAddr = getMipsPageAddr(OutSec->Addr); + uintX_t SymAddr = getMipsPageAddr(B.getVA<ELFT>(Addend)); + uintX_t Index = PageIndexMap.lookup(OutSec) + (SymAddr - SecAddr) / 0xffff; + assert(Index < PageEntriesNum); + return (HeaderEntriesNum + Index) * sizeof(uintX_t); +} + +template <class ELFT> +typename MipsGotSection<ELFT>::uintX_t +MipsGotSection<ELFT>::getBodyEntryOffset(const SymbolBody &B, + uintX_t Addend) const { + // Calculate offset of the GOT entries block: TLS, global, local. + uintX_t Index = HeaderEntriesNum + PageEntriesNum; + if (B.isTls()) + Index += LocalEntries.size() + LocalEntries32.size() + GlobalEntries.size(); + else if (B.IsInGlobalMipsGot) + Index += LocalEntries.size() + LocalEntries32.size(); + else if (B.Is32BitMipsGot) + Index += LocalEntries.size(); + // Calculate offset of the GOT entry in the block. + if (B.isInGot()) + Index += B.GotIndex; + else { + auto It = EntryIndexMap.find({&B, Addend}); + assert(It != EntryIndexMap.end()); + Index += It->second; + } + return Index * sizeof(uintX_t); +} + +template <class ELFT> +typename MipsGotSection<ELFT>::uintX_t +MipsGotSection<ELFT>::getTlsOffset() const { + return (getLocalEntriesNum() + GlobalEntries.size()) * sizeof(uintX_t); +} + +template <class ELFT> +typename MipsGotSection<ELFT>::uintX_t +MipsGotSection<ELFT>::getGlobalDynOffset(const SymbolBody &B) const { + return B.GlobalDynIndex * sizeof(uintX_t); +} + +template <class ELFT> +const SymbolBody *MipsGotSection<ELFT>::getFirstGlobalEntry() const { + return GlobalEntries.empty() ? nullptr : GlobalEntries.front().first; +} + +template <class ELFT> +unsigned MipsGotSection<ELFT>::getLocalEntriesNum() const { + return HeaderEntriesNum + PageEntriesNum + LocalEntries.size() + + LocalEntries32.size(); +} + +template <class ELFT> void MipsGotSection<ELFT>::finalize() { + PageEntriesNum = 0; + for (std::pair<const OutputSectionBase *, size_t> &P : PageIndexMap) { + // For each output section referenced by GOT page relocations calculate + // and save into PageIndexMap an upper bound of MIPS GOT entries required + // to store page addresses of local symbols. We assume the worst case - + // each 64kb page of the output section has at least one GOT relocation + // against it. And take in account the case when the section intersects + // page boundaries. + P.second = PageEntriesNum; + PageEntriesNum += getMipsPageCount(P.first->Size); + } + Size = (getLocalEntriesNum() + GlobalEntries.size() + TlsEntries.size()) * + sizeof(uintX_t); +} + +template <class ELFT> bool MipsGotSection<ELFT>::empty() const { + // We add the .got section to the result for dynamic MIPS target because + // its address and properties are mentioned in the .dynamic section. + return Config->Relocatable; +} + +template <class ELFT> +typename MipsGotSection<ELFT>::uintX_t MipsGotSection<ELFT>::getGp() const { + return ElfSym<ELFT>::MipsGp->template getVA<ELFT>(0); +} + +template <class ELFT> +static void writeUint(uint8_t *Buf, typename ELFT::uint Val) { + typedef typename ELFT::uint uintX_t; + write<uintX_t, ELFT::TargetEndianness, sizeof(uintX_t)>(Buf, Val); +} + +template <class ELFT> void MipsGotSection<ELFT>::writeTo(uint8_t *Buf) { + // Set the MSB of the second GOT slot. This is not required by any + // MIPS ABI documentation, though. + // + // There is a comment in glibc saying that "The MSB of got[1] of a + // gnu object is set to identify gnu objects," and in GNU gold it + // says "the second entry will be used by some runtime loaders". + // But how this field is being used is unclear. + // + // We are not really willing to mimic other linkers behaviors + // without understanding why they do that, but because all files + // generated by GNU tools have this special GOT value, and because + // we've been doing this for years, it is probably a safe bet to + // keep doing this for now. We really need to revisit this to see + // if we had to do this. + auto *P = reinterpret_cast<typename ELFT::Off *>(Buf); + P[1] = uintX_t(1) << (ELFT::Is64Bits ? 63 : 31); + Buf += HeaderEntriesNum * sizeof(uintX_t); + // Write 'page address' entries to the local part of the GOT. + for (std::pair<const OutputSectionBase *, size_t> &L : PageIndexMap) { + size_t PageCount = getMipsPageCount(L.first->Size); + uintX_t FirstPageAddr = getMipsPageAddr(L.first->Addr); + for (size_t PI = 0; PI < PageCount; ++PI) { + uint8_t *Entry = Buf + (L.second + PI) * sizeof(uintX_t); + writeUint<ELFT>(Entry, FirstPageAddr + PI * 0x10000); + } + } + Buf += PageEntriesNum * sizeof(uintX_t); + auto AddEntry = [&](const GotEntry &SA) { + uint8_t *Entry = Buf; + Buf += sizeof(uintX_t); + const SymbolBody *Body = SA.first; + uintX_t VA = Body->template getVA<ELFT>(SA.second); + writeUint<ELFT>(Entry, VA); + }; + std::for_each(std::begin(LocalEntries), std::end(LocalEntries), AddEntry); + std::for_each(std::begin(LocalEntries32), std::end(LocalEntries32), AddEntry); + std::for_each(std::begin(GlobalEntries), std::end(GlobalEntries), AddEntry); + // Initialize TLS-related GOT entries. If the entry has a corresponding + // dynamic relocations, leave it initialized by zero. Write down adjusted + // TLS symbol's values otherwise. To calculate the adjustments use offsets + // for thread-local storage. + // https://www.linux-mips.org/wiki/NPTL + if (TlsIndexOff != -1U && !Config->Pic) + writeUint<ELFT>(Buf + TlsIndexOff, 1); + for (const SymbolBody *B : TlsEntries) { + if (!B || B->isPreemptible()) + continue; + uintX_t VA = B->getVA<ELFT>(); + if (B->GotIndex != -1U) { + uint8_t *Entry = Buf + B->GotIndex * sizeof(uintX_t); + writeUint<ELFT>(Entry, VA - 0x7000); + } + if (B->GlobalDynIndex != -1U) { + uint8_t *Entry = Buf + B->GlobalDynIndex * sizeof(uintX_t); + writeUint<ELFT>(Entry, 1); + Entry += sizeof(uintX_t); + writeUint<ELFT>(Entry, VA - 0x8000); + } + } +} + +template <class ELFT> +GotPltSection<ELFT>::GotPltSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS, + Target->GotPltEntrySize, ".got.plt") {} + +template <class ELFT> void GotPltSection<ELFT>::addEntry(SymbolBody &Sym) { + Sym.GotPltIndex = Target->GotPltHeaderEntriesNum + Entries.size(); + Entries.push_back(&Sym); +} + +template <class ELFT> size_t GotPltSection<ELFT>::getSize() const { + return (Target->GotPltHeaderEntriesNum + Entries.size()) * + Target->GotPltEntrySize; +} + +template <class ELFT> void GotPltSection<ELFT>::writeTo(uint8_t *Buf) { + Target->writeGotPltHeader(Buf); + Buf += Target->GotPltHeaderEntriesNum * Target->GotPltEntrySize; + for (const SymbolBody *B : Entries) { + Target->writeGotPlt(Buf, *B); + Buf += sizeof(uintX_t); + } +} + +// On ARM the IgotPltSection is part of the GotSection, on other Targets it is +// part of the .got.plt +template <class ELFT> +IgotPltSection<ELFT>::IgotPltSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS, + Target->GotPltEntrySize, + Config->EMachine == EM_ARM ? ".got" : ".got.plt") { +} + +template <class ELFT> void IgotPltSection<ELFT>::addEntry(SymbolBody &Sym) { + Sym.IsInIgot = true; + Sym.GotPltIndex = Entries.size(); + Entries.push_back(&Sym); +} + +template <class ELFT> size_t IgotPltSection<ELFT>::getSize() const { + return Entries.size() * Target->GotPltEntrySize; +} + +template <class ELFT> void IgotPltSection<ELFT>::writeTo(uint8_t *Buf) { + for (const SymbolBody *B : Entries) { + Target->writeIgotPlt(Buf, *B); + Buf += sizeof(uintX_t); + } +} + +template <class ELFT> +StringTableSection<ELFT>::StringTableSection(StringRef Name, bool Dynamic) + : SyntheticSection<ELFT>(Dynamic ? (uintX_t)SHF_ALLOC : 0, SHT_STRTAB, 1, + Name), + Dynamic(Dynamic) {} + +// Adds a string to the string table. If HashIt is true we hash and check for +// duplicates. It is optional because the name of global symbols are already +// uniqued and hashing them again has a big cost for a small value: uniquing +// them with some other string that happens to be the same. +template <class ELFT> +unsigned StringTableSection<ELFT>::addString(StringRef S, bool HashIt) { + if (HashIt) { + auto R = StringMap.insert(std::make_pair(S, this->Size)); + if (!R.second) + return R.first->second; + } + unsigned Ret = this->Size; + this->Size = this->Size + S.size() + 1; + Strings.push_back(S); + return Ret; +} + +template <class ELFT> void StringTableSection<ELFT>::writeTo(uint8_t *Buf) { + // ELF string tables start with NUL byte, so advance the pointer by one. + ++Buf; + for (StringRef S : Strings) { + memcpy(Buf, S.data(), S.size()); + Buf += S.size() + 1; + } +} + +// Returns the number of version definition entries. Because the first entry +// is for the version definition itself, it is the number of versioned symbols +// plus one. Note that we don't support multiple versions yet. +static unsigned getVerDefNum() { return Config->VersionDefinitions.size() + 1; } + +template <class ELFT> +DynamicSection<ELFT>::DynamicSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_DYNAMIC, + sizeof(uintX_t), ".dynamic") { + this->Entsize = ELFT::Is64Bits ? 16 : 8; + // .dynamic section is not writable on MIPS. + // See "Special Section" in Chapter 4 in the following document: + // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf + if (Config->EMachine == EM_MIPS) + this->Flags = SHF_ALLOC; + + addEntries(); +} + +// There are some dynamic entries that don't depend on other sections. +// Such entries can be set early. +template <class ELFT> void DynamicSection<ELFT>::addEntries() { + // Add strings to .dynstr early so that .dynstr's size will be + // fixed early. + for (StringRef S : Config->AuxiliaryList) + add({DT_AUXILIARY, In<ELFT>::DynStrTab->addString(S)}); + if (!Config->RPath.empty()) + add({Config->EnableNewDtags ? DT_RUNPATH : DT_RPATH, + In<ELFT>::DynStrTab->addString(Config->RPath)}); + for (SharedFile<ELFT> *F : Symtab<ELFT>::X->getSharedFiles()) + if (F->isNeeded()) + add({DT_NEEDED, In<ELFT>::DynStrTab->addString(F->getSoName())}); + if (!Config->SoName.empty()) + add({DT_SONAME, In<ELFT>::DynStrTab->addString(Config->SoName)}); + + // Set DT_FLAGS and DT_FLAGS_1. + uint32_t DtFlags = 0; + uint32_t DtFlags1 = 0; + if (Config->Bsymbolic) + DtFlags |= DF_SYMBOLIC; + if (Config->ZNodelete) + DtFlags1 |= DF_1_NODELETE; + if (Config->ZNow) { + DtFlags |= DF_BIND_NOW; + DtFlags1 |= DF_1_NOW; + } + if (Config->ZOrigin) { + DtFlags |= DF_ORIGIN; + DtFlags1 |= DF_1_ORIGIN; + } + + if (DtFlags) + add({DT_FLAGS, DtFlags}); + if (DtFlags1) + add({DT_FLAGS_1, DtFlags1}); + + if (!Config->Shared && !Config->Relocatable) + add({DT_DEBUG, (uint64_t)0}); +} + +// Add remaining entries to complete .dynamic contents. +template <class ELFT> void DynamicSection<ELFT>::finalize() { + if (this->Size) + return; // Already finalized. + + this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex; + if (In<ELFT>::RelaDyn->OutSec->Size > 0) { + bool IsRela = Config->Rela; + add({IsRela ? DT_RELA : DT_REL, In<ELFT>::RelaDyn}); + add({IsRela ? DT_RELASZ : DT_RELSZ, In<ELFT>::RelaDyn->OutSec->Size}); + add({IsRela ? DT_RELAENT : DT_RELENT, + uintX_t(IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel))}); + + // MIPS dynamic loader does not support RELCOUNT tag. + // The problem is in the tight relation between dynamic + // relocations and GOT. So do not emit this tag on MIPS. + if (Config->EMachine != EM_MIPS) { + size_t NumRelativeRels = In<ELFT>::RelaDyn->getRelativeRelocCount(); + if (Config->ZCombreloc && NumRelativeRels) + add({IsRela ? DT_RELACOUNT : DT_RELCOUNT, NumRelativeRels}); + } + } + if (In<ELFT>::RelaPlt->OutSec->Size > 0) { + add({DT_JMPREL, In<ELFT>::RelaPlt}); + add({DT_PLTRELSZ, In<ELFT>::RelaPlt->OutSec->Size}); + add({Config->EMachine == EM_MIPS ? DT_MIPS_PLTGOT : DT_PLTGOT, + In<ELFT>::GotPlt}); + add({DT_PLTREL, uint64_t(Config->Rela ? DT_RELA : DT_REL)}); + } + + add({DT_SYMTAB, In<ELFT>::DynSymTab}); + add({DT_SYMENT, sizeof(Elf_Sym)}); + add({DT_STRTAB, In<ELFT>::DynStrTab}); + add({DT_STRSZ, In<ELFT>::DynStrTab->getSize()}); + if (In<ELFT>::GnuHashTab) + add({DT_GNU_HASH, In<ELFT>::GnuHashTab}); + if (In<ELFT>::HashTab) + add({DT_HASH, In<ELFT>::HashTab}); + + if (Out<ELFT>::PreinitArray) { + add({DT_PREINIT_ARRAY, Out<ELFT>::PreinitArray}); + add({DT_PREINIT_ARRAYSZ, Out<ELFT>::PreinitArray, Entry::SecSize}); + } + if (Out<ELFT>::InitArray) { + add({DT_INIT_ARRAY, Out<ELFT>::InitArray}); + add({DT_INIT_ARRAYSZ, Out<ELFT>::InitArray, Entry::SecSize}); + } + if (Out<ELFT>::FiniArray) { + add({DT_FINI_ARRAY, Out<ELFT>::FiniArray}); + add({DT_FINI_ARRAYSZ, Out<ELFT>::FiniArray, Entry::SecSize}); + } + + if (SymbolBody *B = Symtab<ELFT>::X->find(Config->Init)) + add({DT_INIT, B}); + if (SymbolBody *B = Symtab<ELFT>::X->find(Config->Fini)) + add({DT_FINI, B}); + + bool HasVerNeed = In<ELFT>::VerNeed->getNeedNum() != 0; + if (HasVerNeed || In<ELFT>::VerDef) + add({DT_VERSYM, In<ELFT>::VerSym}); + if (In<ELFT>::VerDef) { + add({DT_VERDEF, In<ELFT>::VerDef}); + add({DT_VERDEFNUM, getVerDefNum()}); + } + if (HasVerNeed) { + add({DT_VERNEED, In<ELFT>::VerNeed}); + add({DT_VERNEEDNUM, In<ELFT>::VerNeed->getNeedNum()}); + } + + if (Config->EMachine == EM_MIPS) { + add({DT_MIPS_RLD_VERSION, 1}); + add({DT_MIPS_FLAGS, RHF_NOTPOT}); + add({DT_MIPS_BASE_ADDRESS, Config->ImageBase}); + add({DT_MIPS_SYMTABNO, In<ELFT>::DynSymTab->getNumSymbols()}); + add({DT_MIPS_LOCAL_GOTNO, In<ELFT>::MipsGot->getLocalEntriesNum()}); + if (const SymbolBody *B = In<ELFT>::MipsGot->getFirstGlobalEntry()) + add({DT_MIPS_GOTSYM, B->DynsymIndex}); + else + add({DT_MIPS_GOTSYM, In<ELFT>::DynSymTab->getNumSymbols()}); + add({DT_PLTGOT, In<ELFT>::MipsGot}); + if (In<ELFT>::MipsRldMap) + add({DT_MIPS_RLD_MAP, In<ELFT>::MipsRldMap}); + } + + this->OutSec->Entsize = this->Entsize; + this->OutSec->Link = this->Link; + + // +1 for DT_NULL + this->Size = (Entries.size() + 1) * this->Entsize; +} + +template <class ELFT> void DynamicSection<ELFT>::writeTo(uint8_t *Buf) { + auto *P = reinterpret_cast<Elf_Dyn *>(Buf); + + for (const Entry &E : Entries) { + P->d_tag = E.Tag; + switch (E.Kind) { + case Entry::SecAddr: + P->d_un.d_ptr = E.OutSec->Addr; + break; + case Entry::InSecAddr: + P->d_un.d_ptr = E.InSec->OutSec->Addr + E.InSec->OutSecOff; + break; + case Entry::SecSize: + P->d_un.d_val = E.OutSec->Size; + break; + case Entry::SymAddr: + P->d_un.d_ptr = E.Sym->template getVA<ELFT>(); + break; + case Entry::PlainInt: + P->d_un.d_val = E.Val; + break; + } + ++P; + } +} + +template <class ELFT> +typename ELFT::uint DynamicReloc<ELFT>::getOffset() const { + if (OutputSec) + return OutputSec->Addr + OffsetInSec; + return InputSec->OutSec->Addr + InputSec->getOffset(OffsetInSec); +} + +template <class ELFT> +typename ELFT::uint DynamicReloc<ELFT>::getAddend() const { + if (UseSymVA) + return Sym->getVA<ELFT>(Addend); + return Addend; +} + +template <class ELFT> uint32_t DynamicReloc<ELFT>::getSymIndex() const { + if (Sym && !UseSymVA) + return Sym->DynsymIndex; + return 0; +} + +template <class ELFT> +RelocationSection<ELFT>::RelocationSection(StringRef Name, bool Sort) + : SyntheticSection<ELFT>(SHF_ALLOC, Config->Rela ? SHT_RELA : SHT_REL, + sizeof(uintX_t), Name), + Sort(Sort) { + this->Entsize = Config->Rela ? sizeof(Elf_Rela) : sizeof(Elf_Rel); +} + +template <class ELFT> +void RelocationSection<ELFT>::addReloc(const DynamicReloc<ELFT> &Reloc) { + if (Reloc.Type == Target->RelativeRel) + ++NumRelativeRelocs; + Relocs.push_back(Reloc); +} + +template <class ELFT, class RelTy> +static bool compRelocations(const RelTy &A, const RelTy &B) { + bool AIsRel = A.getType(Config->Mips64EL) == Target->RelativeRel; + bool BIsRel = B.getType(Config->Mips64EL) == Target->RelativeRel; + if (AIsRel != BIsRel) + return AIsRel; + + return A.getSymbol(Config->Mips64EL) < B.getSymbol(Config->Mips64EL); +} + +template <class ELFT> void RelocationSection<ELFT>::writeTo(uint8_t *Buf) { + uint8_t *BufBegin = Buf; + for (const DynamicReloc<ELFT> &Rel : Relocs) { + auto *P = reinterpret_cast<Elf_Rela *>(Buf); + Buf += Config->Rela ? sizeof(Elf_Rela) : sizeof(Elf_Rel); + + if (Config->Rela) + P->r_addend = Rel.getAddend(); + P->r_offset = Rel.getOffset(); + if (Config->EMachine == EM_MIPS && Rel.getInputSec() == In<ELFT>::MipsGot) + // Dynamic relocation against MIPS GOT section make deal TLS entries + // allocated in the end of the GOT. We need to adjust the offset to take + // in account 'local' and 'global' GOT entries. + P->r_offset += In<ELFT>::MipsGot->getTlsOffset(); + P->setSymbolAndType(Rel.getSymIndex(), Rel.Type, Config->Mips64EL); + } + + if (Sort) { + if (Config->Rela) + std::stable_sort((Elf_Rela *)BufBegin, + (Elf_Rela *)BufBegin + Relocs.size(), + compRelocations<ELFT, Elf_Rela>); + else + std::stable_sort((Elf_Rel *)BufBegin, (Elf_Rel *)BufBegin + Relocs.size(), + compRelocations<ELFT, Elf_Rel>); + } +} + +template <class ELFT> unsigned RelocationSection<ELFT>::getRelocOffset() { + return this->Entsize * Relocs.size(); +} + +template <class ELFT> void RelocationSection<ELFT>::finalize() { + this->Link = In<ELFT>::DynSymTab ? In<ELFT>::DynSymTab->OutSec->SectionIndex + : In<ELFT>::SymTab->OutSec->SectionIndex; + + // Set required output section properties. + this->OutSec->Link = this->Link; + this->OutSec->Entsize = this->Entsize; +} + +template <class ELFT> +SymbolTableSection<ELFT>::SymbolTableSection( + StringTableSection<ELFT> &StrTabSec) + : SyntheticSection<ELFT>(StrTabSec.isDynamic() ? (uintX_t)SHF_ALLOC : 0, + StrTabSec.isDynamic() ? SHT_DYNSYM : SHT_SYMTAB, + sizeof(uintX_t), + StrTabSec.isDynamic() ? ".dynsym" : ".symtab"), + StrTabSec(StrTabSec) { + this->Entsize = sizeof(Elf_Sym); +} + +// Orders symbols according to their positions in the GOT, +// in compliance with MIPS ABI rules. +// See "Global Offset Table" in Chapter 5 in the following document +// for detailed description: +// ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf +static bool sortMipsSymbols(const SymbolBody *L, const SymbolBody *R) { + // Sort entries related to non-local preemptible symbols by GOT indexes. + // All other entries go to the first part of GOT in arbitrary order. + bool LIsInLocalGot = !L->IsInGlobalMipsGot; + bool RIsInLocalGot = !R->IsInGlobalMipsGot; + if (LIsInLocalGot || RIsInLocalGot) + return !RIsInLocalGot; + return L->GotIndex < R->GotIndex; +} + +static uint8_t getSymbolBinding(SymbolBody *Body) { + Symbol *S = Body->symbol(); + if (Config->Relocatable) + return S->Binding; + uint8_t Visibility = S->Visibility; + if (Visibility != STV_DEFAULT && Visibility != STV_PROTECTED) + return STB_LOCAL; + if (Config->NoGnuUnique && S->Binding == STB_GNU_UNIQUE) + return STB_GLOBAL; + return S->Binding; +} + +template <class ELFT> void SymbolTableSection<ELFT>::finalize() { + this->OutSec->Link = this->Link = StrTabSec.OutSec->SectionIndex; + this->OutSec->Info = this->Info = NumLocals + 1; + this->OutSec->Entsize = this->Entsize; + + if (Config->Relocatable) { + size_t I = NumLocals; + for (const SymbolTableEntry &S : Symbols) + S.Symbol->DynsymIndex = ++I; + return; + } + + if (!StrTabSec.isDynamic()) { + std::stable_sort(Symbols.begin(), Symbols.end(), + [](const SymbolTableEntry &L, const SymbolTableEntry &R) { + return getSymbolBinding(L.Symbol) == STB_LOCAL && + getSymbolBinding(R.Symbol) != STB_LOCAL; + }); + return; + } + if (In<ELFT>::GnuHashTab) + // NB: It also sorts Symbols to meet the GNU hash table requirements. + In<ELFT>::GnuHashTab->addSymbols(Symbols); + else if (Config->EMachine == EM_MIPS) + std::stable_sort(Symbols.begin(), Symbols.end(), + [](const SymbolTableEntry &L, const SymbolTableEntry &R) { + return sortMipsSymbols(L.Symbol, R.Symbol); + }); + size_t I = 0; + for (const SymbolTableEntry &S : Symbols) + S.Symbol->DynsymIndex = ++I; +} + +template <class ELFT> void SymbolTableSection<ELFT>::addSymbol(SymbolBody *B) { + Symbols.push_back({B, StrTabSec.addString(B->getName(), false)}); +} + +template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) { + Buf += sizeof(Elf_Sym); + + // All symbols with STB_LOCAL binding precede the weak and global symbols. + // .dynsym only contains global symbols. + if (Config->Discard != DiscardPolicy::All && !StrTabSec.isDynamic()) + writeLocalSymbols(Buf); + + writeGlobalSymbols(Buf); +} + +template <class ELFT> +void SymbolTableSection<ELFT>::writeLocalSymbols(uint8_t *&Buf) { + // Iterate over all input object files to copy their local symbols + // to the output symbol table pointed by Buf. + for (ObjectFile<ELFT> *File : Symtab<ELFT>::X->getObjectFiles()) { + for (const std::pair<const DefinedRegular<ELFT> *, size_t> &P : + File->KeptLocalSyms) { + const DefinedRegular<ELFT> &Body = *P.first; + InputSectionBase<ELFT> *Section = Body.Section; + auto *ESym = reinterpret_cast<Elf_Sym *>(Buf); + + if (!Section) { + ESym->st_shndx = SHN_ABS; + ESym->st_value = Body.Value; + } else { + const OutputSectionBase *OutSec = Section->OutSec; + ESym->st_shndx = OutSec->SectionIndex; + ESym->st_value = OutSec->Addr + Section->getOffset(Body); + } + ESym->st_name = P.second; + ESym->st_size = Body.template getSize<ELFT>(); + ESym->setBindingAndType(STB_LOCAL, Body.Type); + Buf += sizeof(*ESym); + } + } +} + +template <class ELFT> +void SymbolTableSection<ELFT>::writeGlobalSymbols(uint8_t *Buf) { + // Write the internal symbol table contents to the output symbol table + // pointed by Buf. + auto *ESym = reinterpret_cast<Elf_Sym *>(Buf); + for (const SymbolTableEntry &S : Symbols) { + SymbolBody *Body = S.Symbol; + size_t StrOff = S.StrTabOffset; + + uint8_t Type = Body->Type; + uintX_t Size = Body->getSize<ELFT>(); + + ESym->setBindingAndType(getSymbolBinding(Body), Type); + ESym->st_size = Size; + ESym->st_name = StrOff; + ESym->setVisibility(Body->symbol()->Visibility); + ESym->st_value = Body->getVA<ELFT>(); + + if (const OutputSectionBase *OutSec = getOutputSection(Body)) + ESym->st_shndx = OutSec->SectionIndex; + else if (isa<DefinedRegular<ELFT>>(Body)) + ESym->st_shndx = SHN_ABS; + + if (Config->EMachine == EM_MIPS) { + // On MIPS we need to mark symbol which has a PLT entry and requires + // pointer equality by STO_MIPS_PLT flag. That is necessary to help + // dynamic linker distinguish such symbols and MIPS lazy-binding stubs. + // https://sourceware.org/ml/binutils/2008-07/txt00000.txt + if (Body->isInPlt() && Body->NeedsCopyOrPltAddr) + ESym->st_other |= STO_MIPS_PLT; + if (Config->Relocatable) { + auto *D = dyn_cast<DefinedRegular<ELFT>>(Body); + if (D && D->isMipsPIC()) + ESym->st_other |= STO_MIPS_PIC; + } + } + ++ESym; + } +} + +template <class ELFT> +const OutputSectionBase * +SymbolTableSection<ELFT>::getOutputSection(SymbolBody *Sym) { + switch (Sym->kind()) { + case SymbolBody::DefinedSyntheticKind: + return cast<DefinedSynthetic>(Sym)->Section; + case SymbolBody::DefinedRegularKind: { + auto &D = cast<DefinedRegular<ELFT>>(*Sym); + if (D.Section) + return D.Section->OutSec; + break; + } + case SymbolBody::DefinedCommonKind: + return In<ELFT>::Common->OutSec; + case SymbolBody::SharedKind: + if (cast<SharedSymbol<ELFT>>(Sym)->needsCopy()) + return Out<ELFT>::Bss; + break; + case SymbolBody::UndefinedKind: + case SymbolBody::LazyArchiveKind: + case SymbolBody::LazyObjectKind: + break; + } + return nullptr; +} + +template <class ELFT> +GnuHashTableSection<ELFT>::GnuHashTableSection() + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_HASH, sizeof(uintX_t), + ".gnu.hash") { + this->Entsize = ELFT::Is64Bits ? 0 : 4; +} + +template <class ELFT> +unsigned GnuHashTableSection<ELFT>::calcNBuckets(unsigned NumHashed) { + if (!NumHashed) + return 0; + + // These values are prime numbers which are not greater than 2^(N-1) + 1. + // In result, for any particular NumHashed we return a prime number + // which is not greater than NumHashed. + static const unsigned Primes[] = { + 1, 1, 3, 3, 7, 13, 31, 61, 127, 251, + 509, 1021, 2039, 4093, 8191, 16381, 32749, 65521, 131071}; + + return Primes[std::min<unsigned>(Log2_32_Ceil(NumHashed), + array_lengthof(Primes) - 1)]; +} + +// Bloom filter estimation: at least 8 bits for each hashed symbol. +// GNU Hash table requirement: it should be a power of 2, +// the minimum value is 1, even for an empty table. +// Expected results for a 32-bit target: +// calcMaskWords(0..4) = 1 +// calcMaskWords(5..8) = 2 +// calcMaskWords(9..16) = 4 +// For a 64-bit target: +// calcMaskWords(0..8) = 1 +// calcMaskWords(9..16) = 2 +// calcMaskWords(17..32) = 4 +template <class ELFT> +unsigned GnuHashTableSection<ELFT>::calcMaskWords(unsigned NumHashed) { + if (!NumHashed) + return 1; + return NextPowerOf2((NumHashed - 1) / sizeof(Elf_Off)); +} + +template <class ELFT> void GnuHashTableSection<ELFT>::finalize() { + unsigned NumHashed = Symbols.size(); + NBuckets = calcNBuckets(NumHashed); + MaskWords = calcMaskWords(NumHashed); + // Second hash shift estimation: just predefined values. + Shift2 = ELFT::Is64Bits ? 6 : 5; + + this->OutSec->Entsize = this->Entsize; + this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex; + this->Size = sizeof(Elf_Word) * 4 // Header + + sizeof(Elf_Off) * MaskWords // Bloom Filter + + sizeof(Elf_Word) * NBuckets // Hash Buckets + + sizeof(Elf_Word) * NumHashed; // Hash Values +} + +template <class ELFT> void GnuHashTableSection<ELFT>::writeTo(uint8_t *Buf) { + writeHeader(Buf); + if (Symbols.empty()) + return; + writeBloomFilter(Buf); + writeHashTable(Buf); +} + +template <class ELFT> +void GnuHashTableSection<ELFT>::writeHeader(uint8_t *&Buf) { + auto *P = reinterpret_cast<Elf_Word *>(Buf); + *P++ = NBuckets; + *P++ = In<ELFT>::DynSymTab->getNumSymbols() - Symbols.size(); + *P++ = MaskWords; + *P++ = Shift2; + Buf = reinterpret_cast<uint8_t *>(P); +} + +template <class ELFT> +void GnuHashTableSection<ELFT>::writeBloomFilter(uint8_t *&Buf) { + unsigned C = sizeof(Elf_Off) * 8; + + auto *Masks = reinterpret_cast<Elf_Off *>(Buf); + for (const SymbolData &Sym : Symbols) { + size_t Pos = (Sym.Hash / C) & (MaskWords - 1); + uintX_t V = (uintX_t(1) << (Sym.Hash % C)) | + (uintX_t(1) << ((Sym.Hash >> Shift2) % C)); + Masks[Pos] |= V; + } + Buf += sizeof(Elf_Off) * MaskWords; +} + +template <class ELFT> +void GnuHashTableSection<ELFT>::writeHashTable(uint8_t *Buf) { + Elf_Word *Buckets = reinterpret_cast<Elf_Word *>(Buf); + Elf_Word *Values = Buckets + NBuckets; + + int PrevBucket = -1; + int I = 0; + for (const SymbolData &Sym : Symbols) { + int Bucket = Sym.Hash % NBuckets; + assert(PrevBucket <= Bucket); + if (Bucket != PrevBucket) { + Buckets[Bucket] = Sym.Body->DynsymIndex; + PrevBucket = Bucket; + if (I > 0) + Values[I - 1] |= 1; + } + Values[I] = Sym.Hash & ~1; + ++I; + } + if (I > 0) + Values[I - 1] |= 1; +} + +static uint32_t hashGnu(StringRef Name) { + uint32_t H = 5381; + for (uint8_t C : Name) + H = (H << 5) + H + C; + return H; +} + +// Add symbols to this symbol hash table. Note that this function +// destructively sort a given vector -- which is needed because +// GNU-style hash table places some sorting requirements. +template <class ELFT> +void GnuHashTableSection<ELFT>::addSymbols(std::vector<SymbolTableEntry> &V) { + // Ideally this will just be 'auto' but GCC 6.1 is not able + // to deduce it correctly. + std::vector<SymbolTableEntry>::iterator Mid = + std::stable_partition(V.begin(), V.end(), [](const SymbolTableEntry &S) { + return S.Symbol->isUndefined(); + }); + if (Mid == V.end()) + return; + for (auto I = Mid, E = V.end(); I != E; ++I) { + SymbolBody *B = I->Symbol; + size_t StrOff = I->StrTabOffset; + Symbols.push_back({B, StrOff, hashGnu(B->getName())}); + } + + unsigned NBuckets = calcNBuckets(Symbols.size()); + std::stable_sort(Symbols.begin(), Symbols.end(), + [&](const SymbolData &L, const SymbolData &R) { + return L.Hash % NBuckets < R.Hash % NBuckets; + }); + + V.erase(Mid, V.end()); + for (const SymbolData &Sym : Symbols) + V.push_back({Sym.Body, Sym.STName}); +} + +template <class ELFT> +HashTableSection<ELFT>::HashTableSection() + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_HASH, sizeof(Elf_Word), ".hash") { + this->Entsize = sizeof(Elf_Word); +} + +template <class ELFT> void HashTableSection<ELFT>::finalize() { + this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex; + this->OutSec->Entsize = this->Entsize; + + unsigned NumEntries = 2; // nbucket and nchain. + NumEntries += In<ELFT>::DynSymTab->getNumSymbols(); // The chain entries. + + // Create as many buckets as there are symbols. + // FIXME: This is simplistic. We can try to optimize it, but implementing + // support for SHT_GNU_HASH is probably even more profitable. + NumEntries += In<ELFT>::DynSymTab->getNumSymbols(); + this->Size = NumEntries * sizeof(Elf_Word); +} + +template <class ELFT> void HashTableSection<ELFT>::writeTo(uint8_t *Buf) { + unsigned NumSymbols = In<ELFT>::DynSymTab->getNumSymbols(); + auto *P = reinterpret_cast<Elf_Word *>(Buf); + *P++ = NumSymbols; // nbucket + *P++ = NumSymbols; // nchain + + Elf_Word *Buckets = P; + Elf_Word *Chains = P + NumSymbols; + + for (const SymbolTableEntry &S : In<ELFT>::DynSymTab->getSymbols()) { + SymbolBody *Body = S.Symbol; + StringRef Name = Body->getName(); + unsigned I = Body->DynsymIndex; + uint32_t Hash = hashSysV(Name) % NumSymbols; + Chains[I] = Buckets[Hash]; + Buckets[Hash] = I; + } +} + +template <class ELFT> +PltSection<ELFT>::PltSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16, + ".plt") {} + +template <class ELFT> void PltSection<ELFT>::writeTo(uint8_t *Buf) { + // At beginning of PLT, we have code to call the dynamic linker + // to resolve dynsyms at runtime. Write such code. + Target->writePltHeader(Buf); + size_t Off = Target->PltHeaderSize; + + for (auto &I : Entries) { + const SymbolBody *B = I.first; + unsigned RelOff = I.second; + uint64_t Got = B->getGotPltVA<ELFT>(); + uint64_t Plt = this->getVA() + Off; + Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff); + Off += Target->PltEntrySize; + } +} + +template <class ELFT> void PltSection<ELFT>::addEntry(SymbolBody &Sym) { + Sym.PltIndex = Entries.size(); + unsigned RelOff = In<ELFT>::RelaPlt->getRelocOffset(); + Entries.push_back(std::make_pair(&Sym, RelOff)); +} + +template <class ELFT> size_t PltSection<ELFT>::getSize() const { + return Target->PltHeaderSize + Entries.size() * Target->PltEntrySize; +} + +template <class ELFT> +IpltSection<ELFT>::IpltSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_EXECINSTR, SHT_PROGBITS, 16, + ".plt") {} + +template <class ELFT> void IpltSection<ELFT>::writeTo(uint8_t *Buf) { + // The IRelative relocations do not support lazy binding so no header is + // needed + size_t Off = 0; + for (auto &I : Entries) { + const SymbolBody *B = I.first; + unsigned RelOff = I.second + In<ELFT>::Plt->getSize(); + uint64_t Got = B->getGotPltVA<ELFT>(); + uint64_t Plt = this->getVA() + Off; + Target->writePlt(Buf + Off, Got, Plt, B->PltIndex, RelOff); + Off += Target->PltEntrySize; + } +} + +template <class ELFT> void IpltSection<ELFT>::addEntry(SymbolBody &Sym) { + Sym.PltIndex = Entries.size(); + Sym.IsInIplt = true; + unsigned RelOff = In<ELFT>::RelaIplt->getRelocOffset(); + Entries.push_back(std::make_pair(&Sym, RelOff)); +} + +template <class ELFT> size_t IpltSection<ELFT>::getSize() const { + return Entries.size() * Target->PltEntrySize; +} + +template <class ELFT> +GdbIndexSection<ELFT>::GdbIndexSection() + : SyntheticSection<ELFT>(0, SHT_PROGBITS, 1, ".gdb_index"), + StringPool(llvm::StringTableBuilder::ELF) {} + +template <class ELFT> void GdbIndexSection<ELFT>::parseDebugSections() { + for (InputSectionBase<ELFT> *S : Symtab<ELFT>::X->Sections) + if (InputSection<ELFT> *IS = dyn_cast<InputSection<ELFT>>(S)) + if (IS->OutSec && IS->Name == ".debug_info") + readDwarf(IS); +} + +// Iterative hash function for symbol's name is described in .gdb_index format +// specification. Note that we use one for version 5 to 7 here, it is different +// for version 4. +static uint32_t hash(StringRef Str) { + uint32_t R = 0; + for (uint8_t C : Str) + R = R * 67 + tolower(C) - 113; + return R; +} + +template <class ELFT> +void GdbIndexSection<ELFT>::readDwarf(InputSection<ELFT> *I) { + GdbIndexBuilder<ELFT> Builder(I); + if (ErrorCount) + return; + + size_t CuId = CompilationUnits.size(); + std::vector<std::pair<uintX_t, uintX_t>> CuList = Builder.readCUList(); + CompilationUnits.insert(CompilationUnits.end(), CuList.begin(), CuList.end()); + + std::vector<AddressEntry<ELFT>> AddrArea = Builder.readAddressArea(CuId); + AddressArea.insert(AddressArea.end(), AddrArea.begin(), AddrArea.end()); + + std::vector<std::pair<StringRef, uint8_t>> NamesAndTypes = + Builder.readPubNamesAndTypes(); + + for (std::pair<StringRef, uint8_t> &Pair : NamesAndTypes) { + uint32_t Hash = hash(Pair.first); + size_t Offset = StringPool.add(Pair.first); + + bool IsNew; + GdbSymbol *Sym; + std::tie(IsNew, Sym) = SymbolTable.add(Hash, Offset); + if (IsNew) { + Sym->CuVectorIndex = CuVectors.size(); + CuVectors.push_back({{CuId, Pair.second}}); + continue; + } + + std::vector<std::pair<uint32_t, uint8_t>> &CuVec = + CuVectors[Sym->CuVectorIndex]; + CuVec.push_back({CuId, Pair.second}); + } +} + +template <class ELFT> void GdbIndexSection<ELFT>::finalize() { + if (Finalized) + return; + Finalized = true; + + parseDebugSections(); + + // GdbIndex header consist from version fields + // and 5 more fields with different kinds of offsets. + CuTypesOffset = CuListOffset + CompilationUnits.size() * CompilationUnitSize; + SymTabOffset = CuTypesOffset + AddressArea.size() * AddressEntrySize; + + ConstantPoolOffset = + SymTabOffset + SymbolTable.getCapacity() * SymTabEntrySize; + + for (std::vector<std::pair<uint32_t, uint8_t>> &CuVec : CuVectors) { + CuVectorsOffset.push_back(CuVectorsSize); + CuVectorsSize += OffsetTypeSize * (CuVec.size() + 1); + } + StringPoolOffset = ConstantPoolOffset + CuVectorsSize; + + StringPool.finalizeInOrder(); +} + +template <class ELFT> size_t GdbIndexSection<ELFT>::getSize() const { + const_cast<GdbIndexSection<ELFT> *>(this)->finalize(); + return StringPoolOffset + StringPool.getSize(); +} + +template <class ELFT> void GdbIndexSection<ELFT>::writeTo(uint8_t *Buf) { + write32le(Buf, 7); // Write version. + write32le(Buf + 4, CuListOffset); // CU list offset. + write32le(Buf + 8, CuTypesOffset); // Types CU list offset. + write32le(Buf + 12, CuTypesOffset); // Address area offset. + write32le(Buf + 16, SymTabOffset); // Symbol table offset. + write32le(Buf + 20, ConstantPoolOffset); // Constant pool offset. + Buf += 24; + + // Write the CU list. + for (std::pair<uintX_t, uintX_t> CU : CompilationUnits) { + write64le(Buf, CU.first); + write64le(Buf + 8, CU.second); + Buf += 16; + } + + // Write the address area. + for (AddressEntry<ELFT> &E : AddressArea) { + uintX_t BaseAddr = E.Section->OutSec->Addr + E.Section->getOffset(0); + write64le(Buf, BaseAddr + E.LowAddress); + write64le(Buf + 8, BaseAddr + E.HighAddress); + write32le(Buf + 16, E.CuIndex); + Buf += 20; + } + + // Write the symbol table. + for (size_t I = 0; I < SymbolTable.getCapacity(); ++I) { + GdbSymbol *Sym = SymbolTable.getSymbol(I); + if (Sym) { + size_t NameOffset = + Sym->NameOffset + StringPoolOffset - ConstantPoolOffset; + size_t CuVectorOffset = CuVectorsOffset[Sym->CuVectorIndex]; + write32le(Buf, NameOffset); + write32le(Buf + 4, CuVectorOffset); + } + Buf += 8; + } + + // Write the CU vectors into the constant pool. + for (std::vector<std::pair<uint32_t, uint8_t>> &CuVec : CuVectors) { + write32le(Buf, CuVec.size()); + Buf += 4; + for (std::pair<uint32_t, uint8_t> &P : CuVec) { + uint32_t Index = P.first; + uint8_t Flags = P.second; + Index |= Flags << 24; + write32le(Buf, Index); + Buf += 4; + } + } + + StringPool.write(Buf); +} + +template <class ELFT> bool GdbIndexSection<ELFT>::empty() const { + return !Out<ELFT>::DebugInfo; +} + +template <class ELFT> +EhFrameHeader<ELFT>::EhFrameHeader() + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_PROGBITS, 1, ".eh_frame_hdr") {} + +// .eh_frame_hdr contains a binary search table of pointers to FDEs. +// Each entry of the search table consists of two values, +// the starting PC from where FDEs covers, and the FDE's address. +// It is sorted by PC. +template <class ELFT> void EhFrameHeader<ELFT>::writeTo(uint8_t *Buf) { + const endianness E = ELFT::TargetEndianness; + + // Sort the FDE list by their PC and uniqueify. Usually there is only + // one FDE for a PC (i.e. function), but if ICF merges two functions + // into one, there can be more than one FDEs pointing to the address. + auto Less = [](const FdeData &A, const FdeData &B) { return A.Pc < B.Pc; }; + std::stable_sort(Fdes.begin(), Fdes.end(), Less); + auto Eq = [](const FdeData &A, const FdeData &B) { return A.Pc == B.Pc; }; + Fdes.erase(std::unique(Fdes.begin(), Fdes.end(), Eq), Fdes.end()); + + Buf[0] = 1; + Buf[1] = DW_EH_PE_pcrel | DW_EH_PE_sdata4; + Buf[2] = DW_EH_PE_udata4; + Buf[3] = DW_EH_PE_datarel | DW_EH_PE_sdata4; + write32<E>(Buf + 4, Out<ELFT>::EhFrame->Addr - this->getVA() - 4); + write32<E>(Buf + 8, Fdes.size()); + Buf += 12; + + uintX_t VA = this->getVA(); + for (FdeData &Fde : Fdes) { + write32<E>(Buf, Fde.Pc - VA); + write32<E>(Buf + 4, Fde.FdeVA - VA); + Buf += 8; + } +} + +template <class ELFT> size_t EhFrameHeader<ELFT>::getSize() const { + // .eh_frame_hdr has a 12 bytes header followed by an array of FDEs. + return 12 + Out<ELFT>::EhFrame->NumFdes * 8; +} + +template <class ELFT> +void EhFrameHeader<ELFT>::addFde(uint32_t Pc, uint32_t FdeVA) { + Fdes.push_back({Pc, FdeVA}); +} + +template <class ELFT> bool EhFrameHeader<ELFT>::empty() const { + return Out<ELFT>::EhFrame->empty(); +} + +template <class ELFT> +VersionDefinitionSection<ELFT>::VersionDefinitionSection() + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_verdef, sizeof(uint32_t), + ".gnu.version_d") {} + +static StringRef getFileDefName() { + if (!Config->SoName.empty()) + return Config->SoName; + return Config->OutputFile; +} + +template <class ELFT> void VersionDefinitionSection<ELFT>::finalize() { + FileDefNameOff = In<ELFT>::DynStrTab->addString(getFileDefName()); + for (VersionDefinition &V : Config->VersionDefinitions) + V.NameOff = In<ELFT>::DynStrTab->addString(V.Name); + + this->OutSec->Link = this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex; + + // sh_info should be set to the number of definitions. This fact is missed in + // documentation, but confirmed by binutils community: + // https://sourceware.org/ml/binutils/2014-11/msg00355.html + this->OutSec->Info = this->Info = getVerDefNum(); +} + +template <class ELFT> +void VersionDefinitionSection<ELFT>::writeOne(uint8_t *Buf, uint32_t Index, + StringRef Name, size_t NameOff) { + auto *Verdef = reinterpret_cast<Elf_Verdef *>(Buf); + Verdef->vd_version = 1; + Verdef->vd_cnt = 1; + Verdef->vd_aux = sizeof(Elf_Verdef); + Verdef->vd_next = sizeof(Elf_Verdef) + sizeof(Elf_Verdaux); + Verdef->vd_flags = (Index == 1 ? VER_FLG_BASE : 0); + Verdef->vd_ndx = Index; + Verdef->vd_hash = hashSysV(Name); + + auto *Verdaux = reinterpret_cast<Elf_Verdaux *>(Buf + sizeof(Elf_Verdef)); + Verdaux->vda_name = NameOff; + Verdaux->vda_next = 0; +} + +template <class ELFT> +void VersionDefinitionSection<ELFT>::writeTo(uint8_t *Buf) { + writeOne(Buf, 1, getFileDefName(), FileDefNameOff); + + for (VersionDefinition &V : Config->VersionDefinitions) { + Buf += sizeof(Elf_Verdef) + sizeof(Elf_Verdaux); + writeOne(Buf, V.Id, V.Name, V.NameOff); + } + + // Need to terminate the last version definition. + Elf_Verdef *Verdef = reinterpret_cast<Elf_Verdef *>(Buf); + Verdef->vd_next = 0; +} + +template <class ELFT> size_t VersionDefinitionSection<ELFT>::getSize() const { + return (sizeof(Elf_Verdef) + sizeof(Elf_Verdaux)) * getVerDefNum(); +} + +template <class ELFT> +VersionTableSection<ELFT>::VersionTableSection() + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_versym, sizeof(uint16_t), + ".gnu.version") {} + +template <class ELFT> void VersionTableSection<ELFT>::finalize() { + this->OutSec->Entsize = this->Entsize = sizeof(Elf_Versym); + // At the moment of june 2016 GNU docs does not mention that sh_link field + // should be set, but Sun docs do. Also readelf relies on this field. + this->OutSec->Link = this->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex; +} + +template <class ELFT> size_t VersionTableSection<ELFT>::getSize() const { + return sizeof(Elf_Versym) * (In<ELFT>::DynSymTab->getSymbols().size() + 1); +} + +template <class ELFT> void VersionTableSection<ELFT>::writeTo(uint8_t *Buf) { + auto *OutVersym = reinterpret_cast<Elf_Versym *>(Buf) + 1; + for (const SymbolTableEntry &S : In<ELFT>::DynSymTab->getSymbols()) { + OutVersym->vs_index = S.Symbol->symbol()->VersionId; + ++OutVersym; + } +} + +template <class ELFT> bool VersionTableSection<ELFT>::empty() const { + return !In<ELFT>::VerDef && In<ELFT>::VerNeed->empty(); +} + +template <class ELFT> +VersionNeedSection<ELFT>::VersionNeedSection() + : SyntheticSection<ELFT>(SHF_ALLOC, SHT_GNU_verneed, sizeof(uint32_t), + ".gnu.version_r") { + // Identifiers in verneed section start at 2 because 0 and 1 are reserved + // for VER_NDX_LOCAL and VER_NDX_GLOBAL. + // First identifiers are reserved by verdef section if it exist. + NextIndex = getVerDefNum() + 1; +} + +template <class ELFT> +void VersionNeedSection<ELFT>::addSymbol(SharedSymbol<ELFT> *SS) { + if (!SS->Verdef) { + SS->symbol()->VersionId = VER_NDX_GLOBAL; + return; + } + SharedFile<ELFT> *F = SS->file(); + // If we don't already know that we need an Elf_Verneed for this DSO, prepare + // to create one by adding it to our needed list and creating a dynstr entry + // for the soname. + if (F->VerdefMap.empty()) + Needed.push_back({F, In<ELFT>::DynStrTab->addString(F->getSoName())}); + typename SharedFile<ELFT>::NeededVer &NV = F->VerdefMap[SS->Verdef]; + // If we don't already know that we need an Elf_Vernaux for this Elf_Verdef, + // prepare to create one by allocating a version identifier and creating a + // dynstr entry for the version name. + if (NV.Index == 0) { + NV.StrTab = In<ELFT>::DynStrTab->addString( + SS->file()->getStringTable().data() + SS->Verdef->getAux()->vda_name); + NV.Index = NextIndex++; + } + SS->symbol()->VersionId = NV.Index; +} + +template <class ELFT> void VersionNeedSection<ELFT>::writeTo(uint8_t *Buf) { + // The Elf_Verneeds need to appear first, followed by the Elf_Vernauxs. + auto *Verneed = reinterpret_cast<Elf_Verneed *>(Buf); + auto *Vernaux = reinterpret_cast<Elf_Vernaux *>(Verneed + Needed.size()); + + for (std::pair<SharedFile<ELFT> *, size_t> &P : Needed) { + // Create an Elf_Verneed for this DSO. + Verneed->vn_version = 1; + Verneed->vn_cnt = P.first->VerdefMap.size(); + Verneed->vn_file = P.second; + Verneed->vn_aux = + reinterpret_cast<char *>(Vernaux) - reinterpret_cast<char *>(Verneed); + Verneed->vn_next = sizeof(Elf_Verneed); + ++Verneed; + + // Create the Elf_Vernauxs for this Elf_Verneed. The loop iterates over + // VerdefMap, which will only contain references to needed version + // definitions. Each Elf_Vernaux is based on the information contained in + // the Elf_Verdef in the source DSO. This loop iterates over a std::map of + // pointers, but is deterministic because the pointers refer to Elf_Verdef + // data structures within a single input file. + for (auto &NV : P.first->VerdefMap) { + Vernaux->vna_hash = NV.first->vd_hash; + Vernaux->vna_flags = 0; + Vernaux->vna_other = NV.second.Index; + Vernaux->vna_name = NV.second.StrTab; + Vernaux->vna_next = sizeof(Elf_Vernaux); + ++Vernaux; + } + + Vernaux[-1].vna_next = 0; + } + Verneed[-1].vn_next = 0; +} + +template <class ELFT> void VersionNeedSection<ELFT>::finalize() { + this->OutSec->Link = this->Link = In<ELFT>::DynStrTab->OutSec->SectionIndex; + this->OutSec->Info = this->Info = Needed.size(); +} + +template <class ELFT> size_t VersionNeedSection<ELFT>::getSize() const { + unsigned Size = Needed.size() * sizeof(Elf_Verneed); + for (const std::pair<SharedFile<ELFT> *, size_t> &P : Needed) + Size += P.first->VerdefMap.size() * sizeof(Elf_Vernaux); + return Size; +} + +template <class ELFT> bool VersionNeedSection<ELFT>::empty() const { + return getNeedNum() == 0; +} + +template <class ELFT> +MipsRldMapSection<ELFT>::MipsRldMapSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_WRITE, SHT_PROGBITS, + sizeof(typename ELFT::uint), ".rld_map") {} + +template <class ELFT> void MipsRldMapSection<ELFT>::writeTo(uint8_t *Buf) { + // Apply filler from linker script. + uint64_t Filler = Script<ELFT>::X->getFiller(this->Name); + Filler = (Filler << 32) | Filler; + memcpy(Buf, &Filler, getSize()); +} + +template <class ELFT> +ARMExidxSentinelSection<ELFT>::ARMExidxSentinelSection() + : SyntheticSection<ELFT>(SHF_ALLOC | SHF_LINK_ORDER, SHT_ARM_EXIDX, + sizeof(typename ELFT::uint), ".ARM.exidx") {} + +// Write a terminating sentinel entry to the end of the .ARM.exidx table. +// This section will have been sorted last in the .ARM.exidx table. +// This table entry will have the form: +// | PREL31 upper bound of code that has exception tables | EXIDX_CANTUNWIND | +template <class ELFT> +void ARMExidxSentinelSection<ELFT>::writeTo(uint8_t *Buf) { + // Get the InputSection before us, we are by definition last + auto RI = cast<OutputSection<ELFT>>(this->OutSec)->Sections.rbegin(); + InputSection<ELFT> *LE = *(++RI); + InputSection<ELFT> *LC = cast<InputSection<ELFT>>(LE->getLinkOrderDep()); + uint64_t S = LC->OutSec->Addr + LC->getOffset(LC->getSize()); + uint64_t P = this->getVA(); + Target->relocateOne(Buf, R_ARM_PREL31, S - P); + write32le(Buf + 4, 0x1); +} + +template InputSection<ELF32LE> *elf::createCommonSection(); +template InputSection<ELF32BE> *elf::createCommonSection(); +template InputSection<ELF64LE> *elf::createCommonSection(); +template InputSection<ELF64BE> *elf::createCommonSection(); + +template InputSection<ELF32LE> *elf::createInterpSection(); +template InputSection<ELF32BE> *elf::createInterpSection(); +template InputSection<ELF64LE> *elf::createInterpSection(); +template InputSection<ELF64BE> *elf::createInterpSection(); + +template MergeInputSection<ELF32LE> *elf::createCommentSection(); +template MergeInputSection<ELF32BE> *elf::createCommentSection(); +template MergeInputSection<ELF64LE> *elf::createCommentSection(); +template MergeInputSection<ELF64BE> *elf::createCommentSection(); + +template class elf::MipsAbiFlagsSection<ELF32LE>; +template class elf::MipsAbiFlagsSection<ELF32BE>; +template class elf::MipsAbiFlagsSection<ELF64LE>; +template class elf::MipsAbiFlagsSection<ELF64BE>; + +template class elf::MipsOptionsSection<ELF32LE>; +template class elf::MipsOptionsSection<ELF32BE>; +template class elf::MipsOptionsSection<ELF64LE>; +template class elf::MipsOptionsSection<ELF64BE>; + +template class elf::MipsReginfoSection<ELF32LE>; +template class elf::MipsReginfoSection<ELF32BE>; +template class elf::MipsReginfoSection<ELF64LE>; +template class elf::MipsReginfoSection<ELF64BE>; + +template class elf::BuildIdSection<ELF32LE>; +template class elf::BuildIdSection<ELF32BE>; +template class elf::BuildIdSection<ELF64LE>; +template class elf::BuildIdSection<ELF64BE>; + +template class elf::GotSection<ELF32LE>; +template class elf::GotSection<ELF32BE>; +template class elf::GotSection<ELF64LE>; +template class elf::GotSection<ELF64BE>; + +template class elf::MipsGotSection<ELF32LE>; +template class elf::MipsGotSection<ELF32BE>; +template class elf::MipsGotSection<ELF64LE>; +template class elf::MipsGotSection<ELF64BE>; + +template class elf::GotPltSection<ELF32LE>; +template class elf::GotPltSection<ELF32BE>; +template class elf::GotPltSection<ELF64LE>; +template class elf::GotPltSection<ELF64BE>; + +template class elf::IgotPltSection<ELF32LE>; +template class elf::IgotPltSection<ELF32BE>; +template class elf::IgotPltSection<ELF64LE>; +template class elf::IgotPltSection<ELF64BE>; + +template class elf::StringTableSection<ELF32LE>; +template class elf::StringTableSection<ELF32BE>; +template class elf::StringTableSection<ELF64LE>; +template class elf::StringTableSection<ELF64BE>; + +template class elf::DynamicSection<ELF32LE>; +template class elf::DynamicSection<ELF32BE>; +template class elf::DynamicSection<ELF64LE>; +template class elf::DynamicSection<ELF64BE>; + +template class elf::RelocationSection<ELF32LE>; +template class elf::RelocationSection<ELF32BE>; +template class elf::RelocationSection<ELF64LE>; +template class elf::RelocationSection<ELF64BE>; + +template class elf::SymbolTableSection<ELF32LE>; +template class elf::SymbolTableSection<ELF32BE>; +template class elf::SymbolTableSection<ELF64LE>; +template class elf::SymbolTableSection<ELF64BE>; + +template class elf::GnuHashTableSection<ELF32LE>; +template class elf::GnuHashTableSection<ELF32BE>; +template class elf::GnuHashTableSection<ELF64LE>; +template class elf::GnuHashTableSection<ELF64BE>; + +template class elf::HashTableSection<ELF32LE>; +template class elf::HashTableSection<ELF32BE>; +template class elf::HashTableSection<ELF64LE>; +template class elf::HashTableSection<ELF64BE>; + +template class elf::PltSection<ELF32LE>; +template class elf::PltSection<ELF32BE>; +template class elf::PltSection<ELF64LE>; +template class elf::PltSection<ELF64BE>; + +template class elf::IpltSection<ELF32LE>; +template class elf::IpltSection<ELF32BE>; +template class elf::IpltSection<ELF64LE>; +template class elf::IpltSection<ELF64BE>; + +template class elf::GdbIndexSection<ELF32LE>; +template class elf::GdbIndexSection<ELF32BE>; +template class elf::GdbIndexSection<ELF64LE>; +template class elf::GdbIndexSection<ELF64BE>; + +template class elf::EhFrameHeader<ELF32LE>; +template class elf::EhFrameHeader<ELF32BE>; +template class elf::EhFrameHeader<ELF64LE>; +template class elf::EhFrameHeader<ELF64BE>; + +template class elf::VersionTableSection<ELF32LE>; +template class elf::VersionTableSection<ELF32BE>; +template class elf::VersionTableSection<ELF64LE>; +template class elf::VersionTableSection<ELF64BE>; + +template class elf::VersionNeedSection<ELF32LE>; +template class elf::VersionNeedSection<ELF32BE>; +template class elf::VersionNeedSection<ELF64LE>; +template class elf::VersionNeedSection<ELF64BE>; + +template class elf::VersionDefinitionSection<ELF32LE>; +template class elf::VersionDefinitionSection<ELF32BE>; +template class elf::VersionDefinitionSection<ELF64LE>; +template class elf::VersionDefinitionSection<ELF64BE>; + +template class elf::MipsRldMapSection<ELF32LE>; +template class elf::MipsRldMapSection<ELF32BE>; +template class elf::MipsRldMapSection<ELF64LE>; +template class elf::MipsRldMapSection<ELF64BE>; + +template class elf::ARMExidxSentinelSection<ELF32LE>; +template class elf::ARMExidxSentinelSection<ELF32BE>; +template class elf::ARMExidxSentinelSection<ELF64LE>; +template class elf::ARMExidxSentinelSection<ELF64BE>; |