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//===- DWARFGdbIndex.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 "llvm/DebugInfo/DWARF/DWARFGdbIndex.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cinttypes>
#include <cstdint>
#include <utility>
using namespace llvm;
// .gdb_index section format reference:
// https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html
void DWARFGdbIndex::dumpCUList(raw_ostream &OS) const {
OS << format("\n CU list offset = 0x%x, has %" PRId64 " entries:",
CuListOffset, (uint64_t)CuList.size())
<< '\n';
uint32_t I = 0;
for (const CompUnitEntry &CU : CuList)
OS << format(" %d: Offset = 0x%llx, Length = 0x%llx\n", I++, CU.Offset,
CU.Length);
}
void DWARFGdbIndex::dumpTUList(raw_ostream &OS) const {
OS << formatv("\n Types CU list offset = {0:x}, has {1} entries:\n",
TuListOffset, TuList.size());
uint32_t I = 0;
for (const TypeUnitEntry &TU : TuList)
OS << formatv(" {0}: offset = {1:x8}, type_offset = {2:x8}, "
"type_signature = {3:x16}\n",
I++, TU.Offset, TU.TypeOffset, TU.TypeSignature);
}
void DWARFGdbIndex::dumpAddressArea(raw_ostream &OS) const {
OS << format("\n Address area offset = 0x%x, has %" PRId64 " entries:",
AddressAreaOffset, (uint64_t)AddressArea.size())
<< '\n';
for (const AddressEntry &Addr : AddressArea)
OS << format(
" Low/High address = [0x%llx, 0x%llx) (Size: 0x%llx), CU id = %d\n",
Addr.LowAddress, Addr.HighAddress, Addr.HighAddress - Addr.LowAddress,
Addr.CuIndex);
}
void DWARFGdbIndex::dumpSymbolTable(raw_ostream &OS) const {
OS << format("\n Symbol table offset = 0x%x, size = %" PRId64
", filled slots:",
SymbolTableOffset, (uint64_t)SymbolTable.size())
<< '\n';
uint32_t I = -1;
for (const SymTableEntry &E : SymbolTable) {
++I;
if (!E.NameOffset && !E.VecOffset)
continue;
OS << format(" %d: Name offset = 0x%x, CU vector offset = 0x%x\n", I,
E.NameOffset, E.VecOffset);
StringRef Name = ConstantPoolStrings.substr(
ConstantPoolOffset - StringPoolOffset + E.NameOffset);
auto CuVector = llvm::find_if(
ConstantPoolVectors,
[&](const std::pair<uint32_t, SmallVector<uint32_t, 0>> &V) {
return V.first == E.VecOffset;
});
assert(CuVector != ConstantPoolVectors.end() && "Invalid symbol table");
uint32_t CuVectorId = CuVector - ConstantPoolVectors.begin();
OS << format(" String name: %s, CU vector index: %d\n", Name.data(),
CuVectorId);
}
}
void DWARFGdbIndex::dumpConstantPool(raw_ostream &OS) const {
OS << format("\n Constant pool offset = 0x%x, has %" PRId64 " CU vectors:",
ConstantPoolOffset, (uint64_t)ConstantPoolVectors.size());
uint32_t I = 0;
for (const auto &V : ConstantPoolVectors) {
OS << format("\n %d(0x%x): ", I++, V.first);
for (uint32_t Val : V.second)
OS << format("0x%x ", Val);
}
OS << '\n';
}
void DWARFGdbIndex::dump(raw_ostream &OS) {
if (HasError) {
OS << "\n<error parsing>\n";
return;
}
if (HasContent) {
OS << " Version = " << Version << '\n';
dumpCUList(OS);
dumpTUList(OS);
dumpAddressArea(OS);
dumpSymbolTable(OS);
dumpConstantPool(OS);
}
}
bool DWARFGdbIndex::parseImpl(DataExtractor Data) {
uint64_t Offset = 0;
// Only version 7 is supported at this moment.
Version = Data.getU32(&Offset);
if (Version != 7)
return false;
CuListOffset = Data.getU32(&Offset);
TuListOffset = Data.getU32(&Offset);
AddressAreaOffset = Data.getU32(&Offset);
SymbolTableOffset = Data.getU32(&Offset);
ConstantPoolOffset = Data.getU32(&Offset);
if (Offset != CuListOffset)
return false;
uint32_t CuListSize = (TuListOffset - CuListOffset) / 16;
CuList.reserve(CuListSize);
for (uint32_t i = 0; i < CuListSize; ++i) {
uint64_t CuOffset = Data.getU64(&Offset);
uint64_t CuLength = Data.getU64(&Offset);
CuList.push_back({CuOffset, CuLength});
}
// CU Types are no longer needed as DWARF skeleton type units never made it
// into the standard.
uint32_t TuListSize = (AddressAreaOffset - TuListOffset) / 24;
TuList.resize(TuListSize);
for (uint32_t I = 0; I < TuListSize; ++I) {
uint64_t CuOffset = Data.getU64(&Offset);
uint64_t TypeOffset = Data.getU64(&Offset);
uint64_t Signature = Data.getU64(&Offset);
TuList[I] = {CuOffset, TypeOffset, Signature};
}
uint32_t AddressAreaSize = (SymbolTableOffset - AddressAreaOffset) / 20;
AddressArea.reserve(AddressAreaSize);
for (uint32_t i = 0; i < AddressAreaSize; ++i) {
uint64_t LowAddress = Data.getU64(&Offset);
uint64_t HighAddress = Data.getU64(&Offset);
uint32_t CuIndex = Data.getU32(&Offset);
AddressArea.push_back({LowAddress, HighAddress, CuIndex});
}
// The symbol table. This is an open addressed hash table. The size of the
// hash table is always a power of 2.
// Each slot in the hash table consists of a pair of offset_type values. The
// first value is the offset of the symbol's name in the constant pool. The
// second value is the offset of the CU vector in the constant pool.
// If both values are 0, then this slot in the hash table is empty. This is ok
// because while 0 is a valid constant pool index, it cannot be a valid index
// for both a string and a CU vector.
uint32_t SymTableSize = (ConstantPoolOffset - SymbolTableOffset) / 8;
SymbolTable.reserve(SymTableSize);
uint32_t CuVectorsTotal = 0;
for (uint32_t i = 0; i < SymTableSize; ++i) {
uint32_t NameOffset = Data.getU32(&Offset);
uint32_t CuVecOffset = Data.getU32(&Offset);
SymbolTable.push_back({NameOffset, CuVecOffset});
if (NameOffset || CuVecOffset)
++CuVectorsTotal;
}
// The constant pool. CU vectors are stored first, followed by strings.
// The first value is the number of CU indices in the vector. Each subsequent
// value is the index and symbol attributes of a CU in the CU list.
for (uint32_t i = 0; i < CuVectorsTotal; ++i) {
ConstantPoolVectors.emplace_back(0, SmallVector<uint32_t, 0>());
auto &Vec = ConstantPoolVectors.back();
Vec.first = Offset - ConstantPoolOffset;
uint32_t Num = Data.getU32(&Offset);
for (uint32_t j = 0; j < Num; ++j)
Vec.second.push_back(Data.getU32(&Offset));
}
ConstantPoolStrings = Data.getData().drop_front(Offset);
StringPoolOffset = Offset;
return true;
}
void DWARFGdbIndex::parse(DataExtractor Data) {
HasContent = !Data.getData().empty();
HasError = HasContent && !parseImpl(Data);
}
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