| //===-- StringTableBuilder.cpp - String table building utility ------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/MC/StringTableBuilder.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/Support/COFF.h" |
| #include "llvm/Support/Endian.h" |
| |
| using namespace llvm; |
| |
| static bool compareBySuffix(StringRef a, StringRef b) { |
| size_t sizeA = a.size(); |
| size_t sizeB = b.size(); |
| size_t len = std::min(sizeA, sizeB); |
| for (size_t i = 0; i < len; ++i) { |
| char ca = a[sizeA - i - 1]; |
| char cb = b[sizeB - i - 1]; |
| if (ca != cb) |
| return ca > cb; |
| } |
| return sizeA > sizeB; |
| } |
| |
| void StringTableBuilder::finalize(Kind kind) { |
| SmallVector<StringRef, 8> Strings; |
| Strings.reserve(StringIndexMap.size()); |
| |
| for (auto i = StringIndexMap.begin(), e = StringIndexMap.end(); i != e; ++i) |
| Strings.push_back(i->getKey()); |
| |
| std::sort(Strings.begin(), Strings.end(), compareBySuffix); |
| |
| switch (kind) { |
| case ELF: |
| case MachO: |
| // Start the table with a NUL byte. |
| StringTable += '\x00'; |
| break; |
| case WinCOFF: |
| // Make room to write the table size later. |
| StringTable.append(4, '\x00'); |
| break; |
| } |
| |
| StringRef Previous; |
| for (StringRef s : Strings) { |
| if (kind == WinCOFF) |
| assert(s.size() > COFF::NameSize && "Short string in COFF string table!"); |
| |
| if (Previous.endswith(s)) { |
| StringIndexMap[s] = StringTable.size() - 1 - s.size(); |
| continue; |
| } |
| |
| StringIndexMap[s] = StringTable.size(); |
| StringTable += s; |
| StringTable += '\x00'; |
| Previous = s; |
| } |
| |
| switch (kind) { |
| case ELF: |
| break; |
| case MachO: |
| // Pad to multiple of 4. |
| while (StringTable.size() % 4) |
| StringTable += '\x00'; |
| break; |
| case WinCOFF: |
| // Write the table size in the first word. |
| assert(StringTable.size() <= std::numeric_limits<uint32_t>::max()); |
| uint32_t size = static_cast<uint32_t>(StringTable.size()); |
| support::endian::write<uint32_t, support::little, support::unaligned>( |
| StringTable.data(), size); |
| break; |
| } |
| } |
| |
| void StringTableBuilder::clear() { |
| StringTable.clear(); |
| StringIndexMap.clear(); |
| } |