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[ELF] - Prepare GnuHashTableSection<ELFT> for detemplation. 

This patch changes GnuHashTableSection implementation
to avoid depend on uintX_t and other ELFT stuff, reducing amount of 
changes for following patch(es).

Differential revision: https://reviews.llvm.org/D31184

llvm-svn: 298998
This commit is contained in:
George Rimar 2017-03-29 15:23:28 +00:00
parent ce957f9070
commit 5f73bc9517
2 changed files with 32 additions and 30 deletions
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58
lld/ELF/SyntheticSections.cpp
View File

@ -846,6 +846,12 @@ uint64_t MipsGotSection::getGp() const {
return ElfSym::MipsGp->getVA(0);
}
static uint64_t readUint(uint8_t *Buf) {
if (Config->Is64)
return read64(Buf, Config->Endianness);
return read32(Buf, Config->Endianness);
}
static void writeUint(uint8_t *Buf, uint64_t Val) {
if (Config->Is64)
write64(Buf, Val, Config->Endianness);
@ -1439,7 +1445,8 @@ template <class ELFT> void SymbolTableSection<ELFT>::writeTo(uint8_t *Buf) {
// safe bet is to specify -hash-style=both for backward compatibilty.
template <class ELFT>
GnuHashTableSection<ELFT>::GnuHashTableSection()
: SyntheticSection(SHF_ALLOC, SHT_GNU_HASH, sizeof(uintX_t), ".gnu.hash") {}
: SyntheticSection(SHF_ALLOC, SHT_GNU_HASH, Config->Wordsize, ".gnu.hash") {
}
template <class ELFT> void GnuHashTableSection<ELFT>::finalizeContents() {
this->OutSec->Link = In<ELFT>::DynSymTab->OutSec->SectionIndex;
@ -1449,26 +1456,27 @@ template <class ELFT> void GnuHashTableSection<ELFT>::finalizeContents() {
if (Symbols.empty())
MaskWords = 1;
else
MaskWords = NextPowerOf2((Symbols.size() - 1) / sizeof(uintX_t));
MaskWords = NextPowerOf2((Symbols.size() - 1) / Config->Wordsize);
Size = 16; // Header
Size += sizeof(uintX_t) * MaskWords; // Bloom filter
Size += NBuckets * 4; // Hash buckets
Size += Symbols.size() * 4; // Hash values
Size = 16; // Header
Size += Config->Wordsize * MaskWords; // Bloom filter
Size += NBuckets * 4; // Hash buckets
Size += Symbols.size() * 4; // Hash values
}
template <class ELFT> void GnuHashTableSection<ELFT>::writeTo(uint8_t *Buf) {
template <class ELFT>
void GnuHashTableSection<ELFT>::writeTo(uint8_t *Buf) {
// Write a header.
const endianness E = ELFT::TargetEndianness;
write32<E>(Buf, NBuckets);
write32<E>(Buf + 4, In<ELFT>::DynSymTab->getNumSymbols() - Symbols.size());
write32<E>(Buf + 8, MaskWords);
write32<E>(Buf + 12, getShift2());
write32(Buf, NBuckets, Config->Endianness);
write32(Buf + 4, In<ELFT>::DynSymTab->getNumSymbols() - Symbols.size(),
Config->Endianness);
write32(Buf + 8, MaskWords, Config->Endianness);
write32(Buf + 12, getShift2(), Config->Endianness);
Buf += 16;
// Write a bloom filter and a hash table.
writeBloomFilter(Buf);
Buf += sizeof(uintX_t) * MaskWords;
Buf += Config->Wordsize * MaskWords;
writeHashTable(Buf);
}
@ -1481,22 +1489,18 @@ template <class ELFT> void GnuHashTableSection<ELFT>::writeTo(uint8_t *Buf) {
// p.9, https://www.akkadia.org/drepper/dsohowto.pdf
template <class ELFT>
void GnuHashTableSection<ELFT>::writeBloomFilter(uint8_t *Buf) {
typedef typename ELFT::Off Elf_Off;
const unsigned C = sizeof(uintX_t) * 8;
auto *Filter = reinterpret_cast<Elf_Off *>(Buf);
const unsigned C = Config->Wordsize * 8;
for (const Entry &Sym : Symbols) {
size_t I = (Sym.Hash / C) & (MaskWords - 1);
Filter[I] |= uintX_t(1) << (Sym.Hash % C);
Filter[I] |= uintX_t(1) << ((Sym.Hash >> getShift2()) % C);
uint64_t Val = readUint(Buf + I * Config->Wordsize);
Val |= uint64_t(1) << (Sym.Hash % C);
Val |= uint64_t(1) << ((Sym.Hash >> getShift2()) % C);
writeUint(Buf + I * Config->Wordsize, Val);
}
}
template <class ELFT>
void GnuHashTableSection<ELFT>::writeHashTable(uint8_t *Buf) {
// A 32-bit integer type in the target endianness.
typedef typename ELFT::Word Elf_Word;
// Group symbols by hash value.
std::vector<std::vector<Entry>> Syms(NBuckets);
for (const Entry &Ent : Symbols)
@ -1504,22 +1508,22 @@ void GnuHashTableSection<ELFT>::writeHashTable(uint8_t *Buf) {
// Write hash buckets. Hash buckets contain indices in the following
// hash value table.
Elf_Word *Buckets = reinterpret_cast<Elf_Word *>(Buf);
uint32_t *Buckets = reinterpret_cast<uint32_t *>(Buf);
for (size_t I = 0; I < NBuckets; ++I)
if (!Syms[I].empty())
Buckets[I] = Syms[I][0].Body->DynsymIndex;
write32(Buckets + I, Syms[I][0].Body->DynsymIndex, Config->Endianness);
// Write a hash value table. It represents a sequence of chains that
// share the same hash modulo value. The last element of each chain
// is terminated by LSB 1.
Elf_Word *Values = Buckets + NBuckets;
uint32_t *Values = Buckets + NBuckets;
size_t I = 0;
for (std::vector<Entry> &Vec : Syms) {
if (Vec.empty())
continue;
for (const Entry &Ent : makeArrayRef(Vec).drop_back())
Values[I++] = Ent.Hash & ~1;
Values[I++] = Vec.back().Hash | 1;
write32(Values + I++, Ent.Hash & ~1, Config->Endianness);
write32(Values + I++, Vec.back().Hash | 1, Config->Endianness);
}
}

4
lld/ELF/SyntheticSections.h
View File

@ -433,8 +433,6 @@ private:
// https://blogs.oracle.com/ali/entry/gnu_hash_elf_sections
template <class ELFT>
class GnuHashTableSection final : public SyntheticSection {
typedef typename ELFT::uint uintX_t;
public:
GnuHashTableSection();
void finalizeContents() override;
@ -446,7 +444,7 @@ public:
void addSymbols(std::vector<SymbolTableEntry> &Symbols);
private:
size_t getShift2() const { return ELFT::Is64Bits ? 6 : 5; }
size_t getShift2() const { return Config->Is64 ? 6 : 5; }
void writeBloomFilter(uint8_t *Buf);
void writeHashTable(uint8_t *Buf);