Files
clang-p2996/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp
2011-09-02 04:03:59 +00:00

148 lines
5.4 KiB
C++

//===-- HashedNameToDIE.cpp -------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "HashedNameToDIE.h"
#include "lldb/Core/ConstString.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/Stream.h"
#include "lldb/Core/StreamString.h"
#include "lldb/Core/RegularExpression.h"
#include "lldb/Symbol/ObjectFile.h"
#include "DWARFCompileUnit.h"
#include "DWARFDebugInfo.h"
#include "DWARFDebugInfoEntry.h"
#include "SymbolFileDWARF.h"
using namespace lldb;
using namespace lldb_private;
static uint32_t
dl_new_hash (const char *s)
{
uint32_t h = 5381;
for (unsigned char c = *s; c; c = *++s)
h = ((h << 5) + h) + c;
return h;
}
HashedNameToDIE::HashedNameToDIE (SymbolFileDWARF *dwarf, const DataExtractor &data) :
m_dwarf (dwarf),
m_data (data),
m_header ()
{
}
void
HashedNameToDIE::Initialize()
{
uint32_t offset = 0;
m_header.version = m_data.GetU16(&offset);
if (m_header.version)
{
m_header.hash_type = m_data.GetU8(&offset);
m_header.hash_index_bitsize = m_data.GetU8(&offset);
m_header.num_buckets = m_data.GetU32(&offset);
m_header.num_hashes = m_data.GetU32(&offset);
m_header.die_offset_base = m_data.GetU32(&offset);
}
}
size_t
HashedNameToDIE::Find (const ConstString &name, DIEArray &die_ofsets) const
{
const size_t initial_size = die_ofsets.size();
const char *name_cstr = name.GetCString();
if (name_cstr && name_cstr[0])
{
// Hash the C string
const uint32_t name_hash = dl_new_hash (name_cstr);
// Find the correct bucket for the using the hash value
const uint32_t bucket_idx = name_hash % m_header.num_buckets;
// Calculate the offset for the bucket entry for the bucket index
uint32_t offset = GetOffsetOfBucketEntry (bucket_idx);
// Extract the bucket entry.
const uint32_t bucket_entry = m_data.GetU32 (&offset);
if (bucket_entry)
{
// The bucket entry is non-zero which means it isn't empty.
// The bucket entry is made up of a hash index whose bit width
// is m_header.hash_index_bitsize, and a hash count whose value
// is the remaining bits in the 32 bit value. Below we extract
// the hash index and the hash count
const uint32_t hash_idx = bucket_entry & GetHashIndexMask();
const uint32_t hash_count = bucket_entry >> m_header.hash_index_bitsize;
const uint32_t hash_end_idx = hash_idx + hash_count;
// Figure out the offset to the hash value by index
uint32_t hash_offset = GetOffsetOfHashValue (hash_idx);
for (uint32_t idx = hash_idx; idx < hash_end_idx; ++idx)
{
// Extract the hash value and see if it matches our string
const uint32_t hash = m_data.GetU32 (&hash_offset);
if (hash == name_hash)
{
// The hash matches, but we still need to verify that the
// C string matches in case we have a hash collision. Figure
// out the offset for the data associated with this hash entry
offset = GetOffsetOfHashDataOffset (idx);
// Extract the first 32 bit value which is the .debug_str offset
// of the string we need
uint32_t hash_data_offset = m_data.GetU32 (&offset);
const uint32_t str_offset = m_data.GetU32 (&hash_data_offset);
// Extract the C string and comapare it
const char *cstr_name = m_dwarf->get_debug_str_data().PeekCStr(str_offset);
if (cstr_name)
{
if (strcmp(name_cstr, cstr_name) == 0)
{
// We have a match, now extract the DIE count
const uint32_t die_count = m_data.GetU32 (&hash_data_offset);
// Now extract "die_count" DIE offsets and put them into the
// results
for (uint32_t die_idx = 0; die_idx < die_count; ++die_idx)
die_ofsets.push_back(m_data.GetU32 (&hash_data_offset));
}
}
}
}
}
}
return die_ofsets.size() - initial_size;
}
size_t
HashedNameToDIE::Find (const RegularExpression& regex, DIEArray &die_ofsets) const
{
// const size_t initial_info_array_size = info_array.size();
// collection::const_iterator pos, end = m_collection.end();
// for (pos = m_collection.begin(); pos != end; ++pos)
// {
// if (regex.Execute(pos->first))
// info_array.push_back (pos->second);
// }
// return info_array.size() - initial_info_array_size;
return 0;
}
void
HashedNameToDIE::Dump (Stream *s)
{
// collection::const_iterator pos, end = m_collection.end();
// for (pos = m_collection.begin(); pos != end; ++pos)
// {
// s->Printf("%p: 0x%8.8x 0x%8.8x \"%s\"\n", pos->first, pos->second.cu_idx, pos->second.die_idx, pos->first);
// }
}