| // Copyright 2018 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "crazy_linker_elf_hash_table.h" |
| |
| #include <string.h> |
| |
| namespace crazy { |
| |
| // Compute the ELF hash of a given symbol. |
| static unsigned ElfHash(const char* name) { |
| const uint8_t* ptr = reinterpret_cast<const uint8_t*>(name); |
| unsigned h = 0; |
| while (*ptr) { |
| h = (h << 4) + *ptr++; |
| unsigned g = h & 0xf0000000; |
| h ^= g; |
| h ^= g >> 24; |
| } |
| return h; |
| } |
| |
| void ElfHashTable::Init(uintptr_t dt_elf_hash) { |
| const ELF::Word* data = reinterpret_cast<const ELF::Word*>(dt_elf_hash); |
| hash_bucket_size_ = data[0]; |
| hash_bucket_ = data + 2; |
| hash_chain_size_ = data[1]; |
| hash_chain_ = hash_bucket_ + hash_bucket_size_; |
| } |
| |
| bool ElfHashTable::IsValid() const { |
| return hash_bucket_size_ > 0; |
| } |
| |
| const ELF::Sym* ElfHashTable::LookupByName(const char* symbol_name, |
| const ELF::Sym* symbol_table, |
| const char* string_table) const { |
| unsigned hash = ElfHash(symbol_name); |
| |
| for (unsigned n = hash_bucket_[hash % hash_bucket_size_]; n != 0; |
| n = hash_chain_[n]) { |
| const ELF::Sym* symbol = &symbol_table[n]; |
| // Check that the symbol has the appropriate name. |
| if (!strcmp(string_table + symbol->st_name, symbol_name)) |
| return symbol; |
| } |
| return nullptr; |
| } |
| |
| } // namespace crazy |