Files
clang-p2996/llvm/tools/dsymutil/MachODebugMapParser.cpp
Jonas Devlieghere 568be31c9e [dsymutil] Initialize the debug map before loading the main binary
Fix a crash when a warning is emitted while loading the symbols from the
main binary. The warning helper assumes that the resulting debug map is
initialized, but this happened after loading the main binary. Since
there's no dependency between the two the initialization can be moved
up.

rdar://107298776
2023-03-27 22:34:42 -07:00

649 lines
23 KiB
C++

//===- tools/dsymutil/MachODebugMapParser.cpp - Parse STABS debug maps ----===//
//
// 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 "BinaryHolder.h"
#include "DebugMap.h"
#include "MachOUtils.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/Object/MachO.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include <optional>
#include <vector>
namespace {
using namespace llvm;
using namespace llvm::dsymutil;
using namespace llvm::object;
class MachODebugMapParser {
public:
MachODebugMapParser(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
StringRef BinaryPath, ArrayRef<std::string> Archs,
StringRef PathPrefix = "",
bool PaperTrailWarnings = false, bool Verbose = false)
: BinaryPath(std::string(BinaryPath)), Archs(Archs.begin(), Archs.end()),
PathPrefix(std::string(PathPrefix)),
PaperTrailWarnings(PaperTrailWarnings), BinHolder(VFS, Verbose),
CurrentDebugMapObject(nullptr) {}
/// Parses and returns the DebugMaps of the input binary. The binary contains
/// multiple maps in case it is a universal binary.
/// \returns an error in case the provided BinaryPath doesn't exist
/// or isn't of a supported type.
ErrorOr<std::vector<std::unique_ptr<DebugMap>>> parse();
/// Walk the symbol table and dump it.
bool dumpStab();
private:
std::string BinaryPath;
SmallVector<StringRef, 1> Archs;
std::string PathPrefix;
bool PaperTrailWarnings;
/// Owns the MemoryBuffer for the main binary.
BinaryHolder BinHolder;
/// Map of the binary symbol addresses.
StringMap<uint64_t> MainBinarySymbolAddresses;
StringRef MainBinaryStrings;
/// The constructed DebugMap.
std::unique_ptr<DebugMap> Result;
/// List of common symbols that need to be added to the debug map.
std::vector<std::string> CommonSymbols;
/// Map of the currently processed object file symbol addresses.
StringMap<std::optional<uint64_t>> CurrentObjectAddresses;
/// Lazily computed map of symbols aliased to the processed object file.
StringMap<std::optional<uint64_t>> CurrentObjectAliasMap;
/// If CurrentObjectAliasMap has been computed for a given address.
SmallSet<uint64_t, 4> SeenAliasValues;
/// Element of the debug map corresponding to the current object file.
DebugMapObject *CurrentDebugMapObject;
/// Holds function info while function scope processing.
const char *CurrentFunctionName;
uint64_t CurrentFunctionAddress;
std::unique_ptr<DebugMap> parseOneBinary(const MachOObjectFile &MainBinary,
StringRef BinaryPath);
void
switchToNewDebugMapObject(StringRef Filename,
sys::TimePoint<std::chrono::seconds> Timestamp);
void resetParserState();
uint64_t getMainBinarySymbolAddress(StringRef Name);
std::vector<StringRef> getMainBinarySymbolNames(uint64_t Value);
void loadMainBinarySymbols(const MachOObjectFile &MainBinary);
void loadCurrentObjectFileSymbols(const object::MachOObjectFile &Obj);
void handleStabSymbolTableEntry(uint32_t StringIndex, uint8_t Type,
uint8_t SectionIndex, uint16_t Flags,
uint64_t Value);
template <typename STEType> void handleStabDebugMapEntry(const STEType &STE) {
handleStabSymbolTableEntry(STE.n_strx, STE.n_type, STE.n_sect, STE.n_desc,
STE.n_value);
}
void addCommonSymbols();
/// Dump the symbol table output header.
void dumpSymTabHeader(raw_ostream &OS, StringRef Arch);
/// Dump the contents of nlist entries.
void dumpSymTabEntry(raw_ostream &OS, uint64_t Index, uint32_t StringIndex,
uint8_t Type, uint8_t SectionIndex, uint16_t Flags,
uint64_t Value);
template <typename STEType>
void dumpSymTabEntry(raw_ostream &OS, uint64_t Index, const STEType &STE) {
dumpSymTabEntry(OS, Index, STE.n_strx, STE.n_type, STE.n_sect, STE.n_desc,
STE.n_value);
}
void dumpOneBinaryStab(const MachOObjectFile &MainBinary,
StringRef BinaryPath);
void Warning(const Twine &Msg, StringRef File = StringRef()) {
assert(Result &&
"The debug map must be initialized before calling this function");
WithColor::warning() << "("
<< MachOUtils::getArchName(
Result->getTriple().getArchName())
<< ") " << File << " " << Msg << "\n";
if (PaperTrailWarnings) {
if (!File.empty())
Result->addDebugMapObject(File, sys::TimePoint<std::chrono::seconds>());
if (Result->end() != Result->begin())
(*--Result->end())->addWarning(Msg.str());
}
}
};
} // anonymous namespace
/// Reset the parser state corresponding to the current object
/// file. This is to be called after an object file is finished
/// processing.
void MachODebugMapParser::resetParserState() {
CommonSymbols.clear();
CurrentObjectAddresses.clear();
CurrentObjectAliasMap.clear();
SeenAliasValues.clear();
CurrentDebugMapObject = nullptr;
}
/// Commons symbols won't show up in the symbol map but might need to be
/// relocated. We can add them to the symbol table ourselves by combining the
/// information in the object file (the symbol name) and the main binary (the
/// address).
void MachODebugMapParser::addCommonSymbols() {
for (auto &CommonSymbol : CommonSymbols) {
uint64_t CommonAddr = getMainBinarySymbolAddress(CommonSymbol);
if (CommonAddr == 0) {
// The main binary doesn't have an address for the given symbol.
continue;
}
if (!CurrentDebugMapObject->addSymbol(CommonSymbol,
std::nullopt /*ObjectAddress*/,
CommonAddr, 0 /*size*/)) {
// The symbol is already present.
continue;
}
}
}
/// Create a new DebugMapObject. This function resets the state of the
/// parser that was referring to the last object file and sets
/// everything up to add symbols to the new one.
void MachODebugMapParser::switchToNewDebugMapObject(
StringRef Filename, sys::TimePoint<std::chrono::seconds> Timestamp) {
addCommonSymbols();
resetParserState();
SmallString<80> Path(PathPrefix);
sys::path::append(Path, Filename);
auto ObjectEntry = BinHolder.getObjectEntry(Path, Timestamp);
if (!ObjectEntry) {
auto Err = ObjectEntry.takeError();
Warning("unable to open object file: " + toString(std::move(Err)),
Path.str());
return;
}
auto Object = ObjectEntry->getObjectAs<MachOObjectFile>(Result->getTriple());
if (!Object) {
auto Err = Object.takeError();
Warning("unable to open object file: " + toString(std::move(Err)),
Path.str());
return;
}
CurrentDebugMapObject =
&Result->addDebugMapObject(Path, Timestamp, MachO::N_OSO);
loadCurrentObjectFileSymbols(*Object);
}
static std::string getArchName(const object::MachOObjectFile &Obj) {
Triple T = Obj.getArchTriple();
return std::string(T.getArchName());
}
std::unique_ptr<DebugMap>
MachODebugMapParser::parseOneBinary(const MachOObjectFile &MainBinary,
StringRef BinaryPath) {
Result = std::make_unique<DebugMap>(MainBinary.getArchTriple(), BinaryPath,
MainBinary.getUuid());
loadMainBinarySymbols(MainBinary);
MainBinaryStrings = MainBinary.getStringTableData();
for (const SymbolRef &Symbol : MainBinary.symbols()) {
const DataRefImpl &DRI = Symbol.getRawDataRefImpl();
if (MainBinary.is64Bit())
handleStabDebugMapEntry(MainBinary.getSymbol64TableEntry(DRI));
else
handleStabDebugMapEntry(MainBinary.getSymbolTableEntry(DRI));
}
resetParserState();
return std::move(Result);
}
// Table that maps Darwin's Mach-O stab constants to strings to allow printing.
// llvm-nm has very similar code, the strings used here are however slightly
// different and part of the interface of dsymutil (some project's build-systems
// parse the ouptut of dsymutil -s), thus they shouldn't be changed.
struct DarwinStabName {
uint8_t NType;
const char *Name;
};
const struct DarwinStabName DarwinStabNames[] = {
{MachO::N_GSYM, "N_GSYM"}, {MachO::N_FNAME, "N_FNAME"},
{MachO::N_FUN, "N_FUN"}, {MachO::N_STSYM, "N_STSYM"},
{MachO::N_LCSYM, "N_LCSYM"}, {MachO::N_BNSYM, "N_BNSYM"},
{MachO::N_PC, "N_PC"}, {MachO::N_AST, "N_AST"},
{MachO::N_OPT, "N_OPT"}, {MachO::N_RSYM, "N_RSYM"},
{MachO::N_SLINE, "N_SLINE"}, {MachO::N_ENSYM, "N_ENSYM"},
{MachO::N_SSYM, "N_SSYM"}, {MachO::N_SO, "N_SO"},
{MachO::N_OSO, "N_OSO"}, {MachO::N_LSYM, "N_LSYM"},
{MachO::N_BINCL, "N_BINCL"}, {MachO::N_SOL, "N_SOL"},
{MachO::N_PARAMS, "N_PARAM"}, {MachO::N_VERSION, "N_VERS"},
{MachO::N_OLEVEL, "N_OLEV"}, {MachO::N_PSYM, "N_PSYM"},
{MachO::N_EINCL, "N_EINCL"}, {MachO::N_ENTRY, "N_ENTRY"},
{MachO::N_LBRAC, "N_LBRAC"}, {MachO::N_EXCL, "N_EXCL"},
{MachO::N_RBRAC, "N_RBRAC"}, {MachO::N_BCOMM, "N_BCOMM"},
{MachO::N_ECOMM, "N_ECOMM"}, {MachO::N_ECOML, "N_ECOML"},
{MachO::N_LENG, "N_LENG"}, {0, nullptr}};
static const char *getDarwinStabString(uint8_t NType) {
for (unsigned i = 0; DarwinStabNames[i].Name; i++) {
if (DarwinStabNames[i].NType == NType)
return DarwinStabNames[i].Name;
}
return nullptr;
}
void MachODebugMapParser::dumpSymTabHeader(raw_ostream &OS, StringRef Arch) {
OS << "-----------------------------------"
"-----------------------------------\n";
OS << "Symbol table for: '" << BinaryPath << "' (" << Arch.data() << ")\n";
OS << "-----------------------------------"
"-----------------------------------\n";
OS << "Index n_strx n_type n_sect n_desc n_value\n";
OS << "======== -------- ------------------ ------ ------ ----------------\n";
}
void MachODebugMapParser::dumpSymTabEntry(raw_ostream &OS, uint64_t Index,
uint32_t StringIndex, uint8_t Type,
uint8_t SectionIndex, uint16_t Flags,
uint64_t Value) {
// Index
OS << '[' << format_decimal(Index, 6)
<< "] "
// n_strx
<< format_hex_no_prefix(StringIndex, 8)
<< ' '
// n_type...
<< format_hex_no_prefix(Type, 2) << " (";
if (Type & MachO::N_STAB)
OS << left_justify(getDarwinStabString(Type), 13);
else {
if (Type & MachO::N_PEXT)
OS << "PEXT ";
else
OS << " ";
switch (Type & MachO::N_TYPE) {
case MachO::N_UNDF: // 0x0 undefined, n_sect == NO_SECT
OS << "UNDF";
break;
case MachO::N_ABS: // 0x2 absolute, n_sect == NO_SECT
OS << "ABS ";
break;
case MachO::N_SECT: // 0xe defined in section number n_sect
OS << "SECT";
break;
case MachO::N_PBUD: // 0xc prebound undefined (defined in a dylib)
OS << "PBUD";
break;
case MachO::N_INDR: // 0xa indirect
OS << "INDR";
break;
default:
OS << format_hex_no_prefix(Type, 2) << " ";
break;
}
if (Type & MachO::N_EXT)
OS << " EXT";
else
OS << " ";
}
OS << ") "
// n_sect
<< format_hex_no_prefix(SectionIndex, 2)
<< " "
// n_desc
<< format_hex_no_prefix(Flags, 4)
<< " "
// n_value
<< format_hex_no_prefix(Value, 16);
const char *Name = &MainBinaryStrings.data()[StringIndex];
if (Name && Name[0])
OS << " '" << Name << "'";
OS << "\n";
}
void MachODebugMapParser::dumpOneBinaryStab(const MachOObjectFile &MainBinary,
StringRef BinaryPath) {
loadMainBinarySymbols(MainBinary);
MainBinaryStrings = MainBinary.getStringTableData();
raw_ostream &OS(llvm::outs());
dumpSymTabHeader(OS, getArchName(MainBinary));
uint64_t Idx = 0;
for (const SymbolRef &Symbol : MainBinary.symbols()) {
const DataRefImpl &DRI = Symbol.getRawDataRefImpl();
if (MainBinary.is64Bit())
dumpSymTabEntry(OS, Idx, MainBinary.getSymbol64TableEntry(DRI));
else
dumpSymTabEntry(OS, Idx, MainBinary.getSymbolTableEntry(DRI));
Idx++;
}
OS << "\n\n";
resetParserState();
}
static bool shouldLinkArch(SmallVectorImpl<StringRef> &Archs, StringRef Arch) {
if (Archs.empty() || is_contained(Archs, "all") || is_contained(Archs, "*"))
return true;
if (Arch.startswith("arm") && Arch != "arm64" && is_contained(Archs, "arm"))
return true;
SmallString<16> ArchName = Arch;
if (Arch.startswith("thumb"))
ArchName = ("arm" + Arch.substr(5)).str();
return is_contained(Archs, ArchName);
}
bool MachODebugMapParser::dumpStab() {
auto ObjectEntry = BinHolder.getObjectEntry(BinaryPath);
if (!ObjectEntry) {
auto Err = ObjectEntry.takeError();
WithColor::error() << "cannot load '" << BinaryPath
<< "': " << toString(std::move(Err)) << '\n';
return false;
}
auto Objects = ObjectEntry->getObjectsAs<MachOObjectFile>();
if (!Objects) {
auto Err = Objects.takeError();
WithColor::error() << "cannot get '" << BinaryPath
<< "' as MachO file: " << toString(std::move(Err))
<< "\n";
return false;
}
for (const auto *Object : *Objects)
if (shouldLinkArch(Archs, Object->getArchTriple().getArchName()))
dumpOneBinaryStab(*Object, BinaryPath);
return true;
}
/// This main parsing routine tries to open the main binary and if
/// successful iterates over the STAB entries. The real parsing is
/// done in handleStabSymbolTableEntry.
ErrorOr<std::vector<std::unique_ptr<DebugMap>>> MachODebugMapParser::parse() {
auto ObjectEntry = BinHolder.getObjectEntry(BinaryPath);
if (!ObjectEntry) {
return errorToErrorCode(ObjectEntry.takeError());
}
auto Objects = ObjectEntry->getObjectsAs<MachOObjectFile>();
if (!Objects) {
return errorToErrorCode(Objects.takeError());
}
std::vector<std::unique_ptr<DebugMap>> Results;
for (const auto *Object : *Objects)
if (shouldLinkArch(Archs, Object->getArchTriple().getArchName()))
Results.push_back(parseOneBinary(*Object, BinaryPath));
return std::move(Results);
}
/// Interpret the STAB entries to fill the DebugMap.
void MachODebugMapParser::handleStabSymbolTableEntry(uint32_t StringIndex,
uint8_t Type,
uint8_t SectionIndex,
uint16_t Flags,
uint64_t Value) {
if (!(Type & MachO::N_STAB))
return;
const char *Name = &MainBinaryStrings.data()[StringIndex];
// An N_OSO entry represents the start of a new object file description.
if (Type == MachO::N_OSO)
return switchToNewDebugMapObject(Name, sys::toTimePoint(Value));
if (Type == MachO::N_AST) {
SmallString<80> Path(PathPrefix);
sys::path::append(Path, Name);
Result->addDebugMapObject(Path, sys::toTimePoint(Value), Type);
return;
}
// If the last N_OSO object file wasn't found, CurrentDebugMapObject will be
// null. Do not update anything until we find the next valid N_OSO entry.
if (!CurrentDebugMapObject)
return;
uint32_t Size = 0;
switch (Type) {
case MachO::N_GSYM:
// This is a global variable. We need to query the main binary
// symbol table to find its address as it might not be in the
// debug map (for common symbols).
Value = getMainBinarySymbolAddress(Name);
break;
case MachO::N_FUN:
// Functions are scopes in STABS. They have an end marker that
// contains the function size.
if (Name[0] == '\0') {
Size = Value;
Value = CurrentFunctionAddress;
Name = CurrentFunctionName;
break;
} else {
CurrentFunctionName = Name;
CurrentFunctionAddress = Value;
return;
}
case MachO::N_STSYM:
break;
default:
return;
}
auto ObjectSymIt = CurrentObjectAddresses.find(Name);
// If the name of a (non-static) symbol is not in the current object, we
// check all its aliases from the main binary.
if (ObjectSymIt == CurrentObjectAddresses.end() && Type != MachO::N_STSYM) {
if (SeenAliasValues.count(Value) == 0) {
auto Aliases = getMainBinarySymbolNames(Value);
for (const auto &Alias : Aliases) {
auto It = CurrentObjectAddresses.find(Alias);
if (It != CurrentObjectAddresses.end()) {
auto AliasValue = It->getValue();
for (const auto &Alias : Aliases)
CurrentObjectAliasMap[Alias] = AliasValue;
break;
}
}
SeenAliasValues.insert(Value);
}
auto AliasIt = CurrentObjectAliasMap.find(Name);
if (AliasIt != CurrentObjectAliasMap.end())
ObjectSymIt = AliasIt;
}
// ThinLTO adds a unique suffix to exported private symbols.
if (ObjectSymIt == CurrentObjectAddresses.end()) {
for (auto Iter = CurrentObjectAddresses.begin();
Iter != CurrentObjectAddresses.end(); ++Iter) {
llvm::StringRef SymbolName = Iter->getKey();
auto Pos = SymbolName.rfind(".llvm.");
if (Pos != llvm::StringRef::npos && SymbolName.substr(0, Pos) == Name) {
ObjectSymIt = Iter;
break;
}
}
}
if (ObjectSymIt == CurrentObjectAddresses.end()) {
Warning("could not find object file symbol for symbol " + Twine(Name));
return;
}
if (!CurrentDebugMapObject->addSymbol(Name, ObjectSymIt->getValue(), Value,
Size)) {
Warning(Twine("failed to insert symbol '") + Name + "' in the debug map.");
return;
}
}
/// Load the current object file symbols into CurrentObjectAddresses.
void MachODebugMapParser::loadCurrentObjectFileSymbols(
const object::MachOObjectFile &Obj) {
CurrentObjectAddresses.clear();
for (auto Sym : Obj.symbols()) {
uint64_t Addr = cantFail(Sym.getValue());
Expected<StringRef> Name = Sym.getName();
if (!Name) {
auto Err = Name.takeError();
Warning("failed to get symbol name: " + toString(std::move(Err)),
Obj.getFileName());
continue;
}
// The value of some categories of symbols isn't meaningful. For
// example common symbols store their size in the value field, not
// their address. Absolute symbols have a fixed address that can
// conflict with standard symbols. These symbols (especially the
// common ones), might still be referenced by relocations. These
// relocations will use the symbol itself, and won't need an
// object file address. The object file address field is optional
// in the DebugMap, leave it unassigned for these symbols.
uint32_t Flags = cantFail(Sym.getFlags());
if (Flags & SymbolRef::SF_Absolute) {
CurrentObjectAddresses[*Name] = std::nullopt;
} else if (Flags & SymbolRef::SF_Common) {
CurrentObjectAddresses[*Name] = std::nullopt;
CommonSymbols.push_back(std::string(*Name));
} else {
CurrentObjectAddresses[*Name] = Addr;
}
}
}
/// Lookup a symbol address in the main binary symbol table. The
/// parser only needs to query common symbols, thus not every symbol's
/// address is available through this function.
uint64_t MachODebugMapParser::getMainBinarySymbolAddress(StringRef Name) {
auto Sym = MainBinarySymbolAddresses.find(Name);
if (Sym == MainBinarySymbolAddresses.end())
return 0;
return Sym->second;
}
/// Get all symbol names in the main binary for the given value.
std::vector<StringRef>
MachODebugMapParser::getMainBinarySymbolNames(uint64_t Value) {
std::vector<StringRef> Names;
for (const auto &Entry : MainBinarySymbolAddresses) {
if (Entry.second == Value)
Names.push_back(Entry.first());
}
return Names;
}
/// Load the interesting main binary symbols' addresses into
/// MainBinarySymbolAddresses.
void MachODebugMapParser::loadMainBinarySymbols(
const MachOObjectFile &MainBinary) {
section_iterator Section = MainBinary.section_end();
MainBinarySymbolAddresses.clear();
for (const auto &Sym : MainBinary.symbols()) {
Expected<SymbolRef::Type> TypeOrErr = Sym.getType();
if (!TypeOrErr) {
auto Err = TypeOrErr.takeError();
Warning("failed to get symbol type: " + toString(std::move(Err)),
MainBinary.getFileName());
continue;
}
SymbolRef::Type Type = *TypeOrErr;
// Skip undefined and STAB entries.
if ((Type == SymbolRef::ST_Debug) || (Type == SymbolRef::ST_Unknown))
continue;
// In theory, the only symbols of interest are the global variables. These
// are the only ones that need to be queried because the address of common
// data won't be described in the debug map. All other addresses should be
// fetched for the debug map. In reality, by playing with 'ld -r' and
// export lists, you can get symbols described as N_GSYM in the debug map,
// but associated with a local symbol. Gather all the symbols, but prefer
// the global ones.
uint8_t SymType =
MainBinary.getSymbolTableEntry(Sym.getRawDataRefImpl()).n_type;
bool Extern = SymType & (MachO::N_EXT | MachO::N_PEXT);
Expected<section_iterator> SectionOrErr = Sym.getSection();
if (!SectionOrErr) {
auto Err = TypeOrErr.takeError();
Warning("failed to get symbol section: " + toString(std::move(Err)),
MainBinary.getFileName());
continue;
}
Section = *SectionOrErr;
if ((Section == MainBinary.section_end() || Section->isText()) && !Extern)
continue;
uint64_t Addr = cantFail(Sym.getValue());
Expected<StringRef> NameOrErr = Sym.getName();
if (!NameOrErr) {
auto Err = NameOrErr.takeError();
Warning("failed to get symbol name: " + toString(std::move(Err)),
MainBinary.getFileName());
continue;
}
StringRef Name = *NameOrErr;
if (Name.size() == 0 || Name[0] == '\0')
continue;
// Override only if the new key is global.
if (Extern)
MainBinarySymbolAddresses[Name] = Addr;
else
MainBinarySymbolAddresses.try_emplace(Name, Addr);
}
}
namespace llvm {
namespace dsymutil {
llvm::ErrorOr<std::vector<std::unique_ptr<DebugMap>>>
parseDebugMap(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
StringRef InputFile, ArrayRef<std::string> Archs,
StringRef PrependPath, bool PaperTrailWarnings, bool Verbose,
bool InputIsYAML) {
if (InputIsYAML)
return DebugMap::parseYAMLDebugMap(InputFile, PrependPath, Verbose);
MachODebugMapParser Parser(VFS, InputFile, Archs, PrependPath,
PaperTrailWarnings, Verbose);
return Parser.parse();
}
bool dumpStab(llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
StringRef InputFile, ArrayRef<std::string> Archs,
StringRef PrependPath) {
MachODebugMapParser Parser(VFS, InputFile, Archs, PrependPath, false);
return Parser.dumpStab();
}
} // namespace dsymutil
} // namespace llvm