Files
clang-p2996/lldb/source/Plugins/SymbolFile/DWARF/NameToDIE.cpp
Greg Clayton a2154b1951 Cache the manual DWARF index out to the LLDB cache directory when the LLDB index cache is enabled.
This patch add the ability to cache the manual DWARF indexing results to disk for faster subsequent debug sessions. Manual DWARF indexing is time consuming and causes all DWARF to be fully parsed and indexed each time you debug a binary that doesn't have an acceptable accelerator table. Acceptable accelerator tables include .debug_names in DWARF5 or Apple accelerator tables.

This patch breaks up testing by testing all of the encoding and decoding of required C++ objects in a gtest unit test, and then has a test to verify the debug info cache is generated correctly.

This patch also adds the ability to track when a symbol table or DWARF index is loaded or saved to the cache in the "statistics dump" command. This is essential to know in statistics as it can help explain why a debug session was slower or faster than expected.

Reviewed By: labath, wallace

Differential Revision: https://reviews.llvm.org/D115951
2021-12-28 11:00:28 -08:00

140 lines
4.5 KiB
C++

//===-- NameToDIE.cpp -----------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "NameToDIE.h"
#include "DWARFUnit.h"
#include "lldb/Core/DataFileCache.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/DataEncoder.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/RegularExpression.h"
#include "lldb/Utility/Stream.h"
#include "lldb/Utility/StreamString.h"
using namespace lldb;
using namespace lldb_private;
void NameToDIE::Finalize() {
m_map.Sort();
m_map.SizeToFit();
}
void NameToDIE::Insert(ConstString name, const DIERef &die_ref) {
m_map.Append(name, die_ref);
}
bool NameToDIE::Find(ConstString name,
llvm::function_ref<bool(DIERef ref)> callback) const {
for (const auto &entry : m_map.equal_range(name))
if (!callback(entry.value))
return false;
return true;
}
bool NameToDIE::Find(const RegularExpression &regex,
llvm::function_ref<bool(DIERef ref)> callback) const {
for (const auto &entry : m_map)
if (regex.Execute(entry.cstring.GetCString())) {
if (!callback(entry.value))
return false;
}
return true;
}
void NameToDIE::FindAllEntriesForUnit(
DWARFUnit &s_unit, llvm::function_ref<bool(DIERef ref)> callback) const {
lldbassert(!s_unit.GetSymbolFileDWARF().GetDwoNum());
const DWARFUnit &ns_unit = s_unit.GetNonSkeletonUnit();
const uint32_t size = m_map.GetSize();
for (uint32_t i = 0; i < size; ++i) {
const DIERef &die_ref = m_map.GetValueAtIndexUnchecked(i);
if (ns_unit.GetSymbolFileDWARF().GetDwoNum() == die_ref.dwo_num() &&
ns_unit.GetDebugSection() == die_ref.section() &&
ns_unit.GetOffset() <= die_ref.die_offset() &&
die_ref.die_offset() < ns_unit.GetNextUnitOffset()) {
if (!callback(die_ref))
return;
}
}
}
void NameToDIE::Dump(Stream *s) {
const uint32_t size = m_map.GetSize();
for (uint32_t i = 0; i < size; ++i) {
s->Format("{0} \"{1}\"\n", m_map.GetValueAtIndexUnchecked(i),
m_map.GetCStringAtIndexUnchecked(i));
}
}
void NameToDIE::ForEach(
std::function<bool(ConstString name, const DIERef &die_ref)> const
&callback) const {
const uint32_t size = m_map.GetSize();
for (uint32_t i = 0; i < size; ++i) {
if (!callback(m_map.GetCStringAtIndexUnchecked(i),
m_map.GetValueAtIndexUnchecked(i)))
break;
}
}
void NameToDIE::Append(const NameToDIE &other) {
const uint32_t size = other.m_map.GetSize();
for (uint32_t i = 0; i < size; ++i) {
m_map.Append(other.m_map.GetCStringAtIndexUnchecked(i),
other.m_map.GetValueAtIndexUnchecked(i));
}
}
constexpr llvm::StringLiteral kIdentifierNameToDIE("N2DI");
bool NameToDIE::Decode(const DataExtractor &data, lldb::offset_t *offset_ptr,
const StringTableReader &strtab) {
m_map.Clear();
llvm::StringRef identifier((const char *)data.GetData(offset_ptr, 4), 4);
if (identifier != kIdentifierNameToDIE)
return false;
const uint32_t count = data.GetU32(offset_ptr);
for (uint32_t i = 0; i < count; ++i) {
llvm::StringRef str(strtab.Get(data.GetU32(offset_ptr)));
// No empty strings allowed in the name to DIE maps.
if (str.empty())
return false;
if (llvm::Optional<DIERef> die_ref = DIERef::Decode(data, offset_ptr))
m_map.Append(ConstString(str), die_ref.getValue());
else
return false;
}
return true;
}
void NameToDIE::Encode(DataEncoder &encoder, ConstStringTable &strtab) const {
encoder.AppendData(kIdentifierNameToDIE);
encoder.AppendU32(m_map.GetSize());
for (const auto &entry : m_map) {
// Make sure there are no empty strings.
assert((bool)entry.cstring);
encoder.AppendU32(strtab.Add(entry.cstring));
entry.value.Encode(encoder);
}
}
bool NameToDIE::operator==(const NameToDIE &rhs) const {
const size_t size = m_map.GetSize();
if (size != rhs.m_map.GetSize())
return false;
for (size_t i = 0; i < size; ++i) {
if (m_map.GetCStringAtIndex(i) != rhs.m_map.GetCStringAtIndex(i))
return false;
if (m_map.GetValueRefAtIndexUnchecked(i) !=
rhs.m_map.GetValueRefAtIndexUnchecked(i))
return false;
}
return true;
}