llvm/lib/DebugInfo/PDB/Native/StringTable.cpp
2017-03-15 22:19:30 +00:00

110 lines
3.6 KiB
C++

//===- StringTable.cpp - PDB String Table -----------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/PDB/Native/StringTable.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/DebugInfo/PDB/Native/Hash.h"
#include "llvm/DebugInfo/PDB/Native/RawError.h"
#include "llvm/DebugInfo/PDB/Native/RawTypes.h"
#include "llvm/Support/BinaryStreamReader.h"
#include "llvm/Support/Endian.h"
using namespace llvm;
using namespace llvm::support;
using namespace llvm::pdb;
StringTable::StringTable() {}
Error StringTable::load(BinaryStreamReader &Stream) {
ByteSize = Stream.getLength();
const StringTableHeader *H;
if (auto EC = Stream.readObject(H))
return EC;
if (H->Signature != StringTableSignature)
return make_error<RawError>(raw_error_code::corrupt_file,
"Invalid hash table signature");
if (H->HashVersion != 1 && H->HashVersion != 2)
return make_error<RawError>(raw_error_code::corrupt_file,
"Unsupported hash version");
Signature = H->Signature;
HashVersion = H->HashVersion;
if (auto EC = Stream.readStreamRef(NamesBuffer, H->ByteSize))
return joinErrors(std::move(EC),
make_error<RawError>(raw_error_code::corrupt_file,
"Invalid hash table byte length"));
const support::ulittle32_t *HashCount;
if (auto EC = Stream.readObject(HashCount))
return EC;
if (auto EC = Stream.readArray(IDs, *HashCount))
return joinErrors(std::move(EC),
make_error<RawError>(raw_error_code::corrupt_file,
"Could not read bucket array"));
if (Stream.bytesRemaining() < sizeof(support::ulittle32_t))
return make_error<RawError>(raw_error_code::corrupt_file,
"Missing name count");
if (auto EC = Stream.readInteger(NameCount))
return EC;
if (Stream.bytesRemaining() > 0)
return make_error<RawError>(raw_error_code::stream_too_long,
"Unexpected bytes found in string table");
return Error::success();
}
uint32_t StringTable::getByteSize() const {
return ByteSize;
}
StringRef StringTable::getStringForID(uint32_t ID) const {
if (ID == IDs[0])
return StringRef();
// NamesBuffer is a buffer of null terminated strings back to back. ID is
// the starting offset of the string we're looking for. So just seek into
// the desired offset and a read a null terminated stream from that offset.
StringRef Result;
BinaryStreamReader NameReader(NamesBuffer);
NameReader.setOffset(ID);
if (auto EC = NameReader.readCString(Result))
consumeError(std::move(EC));
return Result;
}
uint32_t StringTable::getIDForString(StringRef Str) const {
uint32_t Hash = (HashVersion == 1) ? hashStringV1(Str) : hashStringV2(Str);
size_t Count = IDs.size();
uint32_t Start = Hash % Count;
for (size_t I = 0; I < Count; ++I) {
// The hash is just a starting point for the search, but if it
// doesn't work we should find the string no matter what, because
// we iterate the entire array.
uint32_t Index = (Start + I) % Count;
uint32_t ID = IDs[Index];
StringRef S = getStringForID(ID);
if (S == Str)
return ID;
}
// IDs[0] contains the ID of the "invalid" entry.
return IDs[0];
}
FixedStreamArray<support::ulittle32_t> StringTable::name_ids() const {
return IDs;
}