llvm-project/lld/lib/ReaderWriter/PECOFF/ReaderCOFF.cpp

395 lines
11 KiB
C++

//===- lib/ReaderWriter/PECOFF/ReaderCOFF.cpp -----------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lld/ReaderWriter/ReaderPECOFF.h"
#include "lld/Core/File.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Object/COFF.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Memory.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/system_error.h"
#include <map>
#include <vector>
using llvm::object::coff_symbol;
using namespace lld;
namespace { // anonymous
class COFFAbsoluteAtom : public AbsoluteAtom {
public:
COFFAbsoluteAtom(const File &F, llvm::StringRef N, uint64_t V)
: OwningFile(F)
, Name(N)
, Value(V)
{}
virtual const class File &file() const {
return OwningFile;
}
virtual llvm::StringRef name() const {
return Name;
}
virtual uint64_t value() const {
return Value;
}
private:
const File &OwningFile;
llvm::StringRef Name;
uint64_t Value;
};
class COFFUndefinedAtom : public UndefinedAtom {
public:
COFFUndefinedAtom(const File &F, llvm::StringRef N)
: OwningFile(F)
, Name(N)
{}
virtual const class File &file() const {
return OwningFile;
}
virtual llvm::StringRef name() const {
return Name;
}
virtual CanBeNull canBeNull() const {
return CanBeNull::canBeNullNever;
}
private:
const File &OwningFile;
llvm::StringRef Name;
};
class COFFDefinedAtom : public DefinedAtom {
public:
COFFDefinedAtom( const File &F
, llvm::StringRef N
, const llvm::object::coff_symbol *Symb
, const llvm::object::coff_section *Sec
, llvm::ArrayRef<uint8_t> D)
: OwningFile(F)
, Name(N)
, Symbol(Symb)
, Section(Sec)
, Data(D)
{}
virtual const class File &file() const {
return OwningFile;
}
virtual llvm::StringRef name() const {
return Name;
}
virtual uint64_t ordinal() const {
return reinterpret_cast<intptr_t>(Symbol);
}
virtual uint64_t size() const {
return Data.size();
}
virtual Scope scope() const {
if (!Symbol)
return scopeTranslationUnit;
switch (Symbol->StorageClass) {
case llvm::COFF::IMAGE_SYM_CLASS_EXTERNAL:
return scopeGlobal;
case llvm::COFF::IMAGE_SYM_CLASS_STATIC:
return scopeTranslationUnit;
}
llvm_unreachable("Unknown scope!");
}
virtual Interposable interposable() const {
return interposeNo;
}
virtual Merge merge() const {
return mergeNo;
}
virtual ContentType contentType() const {
if (Section->Characteristics & llvm::COFF::IMAGE_SCN_CNT_CODE)
return typeCode;
if (Section->Characteristics & llvm::COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
return typeData;
if (Section->Characteristics & llvm::COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
return typeZeroFill;
return typeUnknown;
}
virtual Alignment alignment() const {
return Alignment(1);
}
virtual SectionChoice sectionChoice() const {
return sectionBasedOnContent;
}
virtual llvm::StringRef customSectionName() const {
return "";
}
virtual DeadStripKind deadStrip() const {
return deadStripNormal;
}
virtual ContentPermissions permissions() const {
if ( Section->Characteristics & llvm::COFF::IMAGE_SCN_MEM_READ
&& Section->Characteristics & llvm::COFF::IMAGE_SCN_MEM_WRITE)
return permRW_;
if ( Section->Characteristics & llvm::COFF::IMAGE_SCN_MEM_READ
&& Section->Characteristics & llvm::COFF::IMAGE_SCN_MEM_EXECUTE)
return permR_X;
if (Section->Characteristics & llvm::COFF::IMAGE_SCN_MEM_READ)
return permR__;
return perm___;
}
virtual bool isThumb() const {
return false;
}
virtual bool isAlias() const {
return false;
}
virtual llvm::ArrayRef<uint8_t> rawContent() const {
return Data;
}
virtual reference_iterator begin() const {
return reference_iterator(*this, nullptr);
}
virtual reference_iterator end() const {
return reference_iterator(*this, nullptr);
}
private:
virtual const Reference *derefIterator(const void *iter) const {
return nullptr;
}
virtual void incrementIterator(const void *&iter) const {
}
const File &OwningFile;
llvm::StringRef Name;
const llvm::object::coff_symbol *Symbol;
const llvm::object::coff_section *Section;
llvm::ArrayRef<uint8_t> Data;
};
class FileCOFF : public File {
public:
FileCOFF(std::unique_ptr<llvm::MemoryBuffer> MB, llvm::error_code &EC)
: File(MB->getBufferIdentifier()) {
llvm::OwningPtr<llvm::object::Binary> Bin;
EC = llvm::object::createBinary(MB.release(), Bin);
if (EC)
return;
Obj.reset(llvm::dyn_cast<const llvm::object::COFFObjectFile>(Bin.get()));
if (!Obj) {
EC = make_error_code(llvm::object::object_error::invalid_file_type);
return;
}
Bin.take();
const llvm::object::coff_file_header *Header = nullptr;
if ((EC = Obj->getHeader(Header)))
return;
// Assign each symbol to the section it's in. If it does not belong to a
// section, create an atom for it now.
std::map< const llvm::object::coff_section*
, std::vector<const llvm::object::coff_symbol*>> SectionSymbols;
for (uint32_t i = 0, e = Header->NumberOfSymbols; i != e; ++i) {
const llvm::object::coff_symbol *Symb;
if ((EC = Obj->getSymbol(i, Symb)))
return;
llvm::StringRef Name;
if ((EC = Obj->getSymbolName(Symb, Name)))
return;
int16_t SectionIndex = Symb->SectionNumber;
assert(SectionIndex != llvm::COFF::IMAGE_SYM_DEBUG &&
"Cannot atomize IMAGE_SYM_DEBUG!");
if (SectionIndex == llvm::COFF::IMAGE_SYM_ABSOLUTE) {
// Create an absolute atom.
AbsoluteAtoms._atoms.push_back(
new (AtomStorage.Allocate<COFFAbsoluteAtom>())
COFFAbsoluteAtom(*this, Name, Symb->Value));
} else if (SectionIndex == llvm::COFF::IMAGE_SYM_UNDEFINED) {
// Create an undefined atom.
UndefinedAtoms._atoms.push_back(
new (AtomStorage.Allocate<COFFUndefinedAtom>())
COFFUndefinedAtom(*this, Name));
} else {
// This is actually a defined symbol. Add it to its section's list of
// symbols.
uint8_t SC = Symb->StorageClass;
// If Symb->Value actually means section offset.
if ( SC == llvm::COFF::IMAGE_SYM_CLASS_EXTERNAL
|| SC == llvm::COFF::IMAGE_SYM_CLASS_STATIC
|| SC == llvm::COFF::IMAGE_SYM_CLASS_FUNCTION) {
const llvm::object::coff_section *Sec;
if ((EC = Obj->getSection(SectionIndex, Sec)))
return;
assert(Sec && "SectionIndex > 0, Sec must be non-null!");
SectionSymbols[Sec].push_back(Symb);
} else {
llvm::errs() << "Unable to create atom for: " << Name << "\n";
EC = llvm::object::object_error::parse_failed;
return;
}
}
// Skip aux symbols.
i += Symb->NumberOfAuxSymbols;
}
// For each section, sort its symbols by address, then create a defined atom
// for each range.
for (auto &i : SectionSymbols) {
auto &Symbs = i.second;
// Sort symbols by position.
std::stable_sort(Symbs.begin(), Symbs.end(),
// For some reason MSVC fails to allow the lambda in this context with a
// "illegal use of local type in type instantiation". MSVC is clearly
// wrong here. Force a conversion to function pointer to work around.
static_cast<bool(*)(const coff_symbol*, const coff_symbol*)>(
[](const coff_symbol *A, const coff_symbol *B) -> bool {
return A->Value < B->Value;
}));
if (Symbs.empty()) {
// Create an atom for the entire section.
llvm::ArrayRef<uint8_t> Data;
DefinedAtoms._atoms.push_back(
new (AtomStorage.Allocate<COFFDefinedAtom>())
COFFDefinedAtom(*this, "", nullptr, i.first, Data));
continue;
}
llvm::ArrayRef<uint8_t> SecData;
if ((EC = Obj->getSectionContents(i.first, SecData)))
return;
// Create an unnamed atom if the first atom isn't at the start of the
// section.
if (Symbs[0]->Value != 0) {
uint64_t Size = Symbs[0]->Value;
llvm::ArrayRef<uint8_t> Data(SecData.data(), Size);
DefinedAtoms._atoms.push_back(
new (AtomStorage.Allocate<COFFDefinedAtom>())
COFFDefinedAtom(*this, "", nullptr, i.first, Data));
}
for (auto si = Symbs.begin(), se = Symbs.end(); si != se; ++si) {
// if this is the last symbol, take up the remaining data.
llvm::ArrayRef<uint8_t> Data;
if (si + 1 == se) {
Data = llvm::ArrayRef<uint8_t>( SecData.data() + (*si)->Value
, SecData.end());
} else {
Data = llvm::ArrayRef<uint8_t>( SecData.data() + (*si)->Value
, (*(si + 1))->Value - (*si)->Value);
}
llvm::StringRef Name;
if ((EC = Obj->getSymbolName(*si, Name)))
return;
DefinedAtoms._atoms.push_back(
new (AtomStorage.Allocate<COFFDefinedAtom>())
COFFDefinedAtom(*this, Name, *si, i.first, Data));
}
}
}
virtual void addAtom(const Atom&) {
llvm_unreachable("cannot add atoms to native .obj files");
}
virtual const atom_collection<DefinedAtom> &defined() const {
return DefinedAtoms;
}
virtual const atom_collection<UndefinedAtom> &undefined() const {
return UndefinedAtoms;
}
virtual const atom_collection<SharedLibraryAtom> &sharedLibrary() const {
return SharedLibraryAtoms;
}
virtual const atom_collection<AbsoluteAtom> &absolute() const {
return AbsoluteAtoms;
}
private:
std::unique_ptr<const llvm::object::COFFObjectFile> Obj;
atom_collection_vector<DefinedAtom> DefinedAtoms;
atom_collection_vector<UndefinedAtom> UndefinedAtoms;
atom_collection_vector<SharedLibraryAtom> SharedLibraryAtoms;
atom_collection_vector<AbsoluteAtom> AbsoluteAtoms;
llvm::BumpPtrAllocator AtomStorage;
};
class ReaderCOFF : public Reader {
public:
ReaderCOFF(const ReaderOptionsPECOFF &options) {}
error_code parseFile(std::unique_ptr<MemoryBuffer> mb,
std::vector<std::unique_ptr<File>> &result) {
llvm::error_code ec;
std::unique_ptr<File> f(new FileCOFF(std::move(mb), ec));
if (ec) {
return ec;
}
result.push_back(std::move(f));
return error_code::success();
}
};
} // namespace anonymous
namespace lld {
Reader *createReaderPECOFF(const ReaderOptionsPECOFF &options) {
return new ReaderCOFF(options);
}
ReaderOptionsPECOFF::ReaderOptionsPECOFF() {
}
ReaderOptionsPECOFF::~ReaderOptionsPECOFF() {
}
} // namespace lld