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//===- lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp --------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file Converts from in-memory normalized mach-o to in-memory Atoms.
///
/// +------------+
/// | normalized |
/// +------------+
/// |
/// |
/// v
/// +-------+
/// | Atoms |
/// +-------+
#include "MachONormalizedFile.h"
#include "File.h"
#include "Atoms.h"
#include "lld/Core/LLVM.h"
#include "llvm/Support/MachO.h"
using namespace llvm::MachO;
namespace lld {
namespace mach_o {
namespace normalized {
static uint64_t nextSymbolAddress(const NormalizedFile &normalizedFile,
const Symbol &symbol) {
uint64_t symbolAddr = symbol.value;
uint8_t symbolSectionIndex = symbol.sect;
const Section §ion = normalizedFile.sections[symbolSectionIndex - 1];
// If no symbol after this address, use end of section address.
uint64_t closestAddr = section.address + section.content.size();
for (const Symbol &s : normalizedFile.globalSymbols) {
if (s.sect != symbolSectionIndex)
continue;
uint64_t sValue = s.value;
if (sValue <= symbolAddr)
continue;
if (sValue < closestAddr)
closestAddr = s.value;
}
for (const Symbol &s : normalizedFile.localSymbols) {
if (s.sect != symbolSectionIndex)
continue;
uint64_t sValue = s.value;
if (sValue <= symbolAddr)
continue;
if (sValue < closestAddr)
closestAddr = s.value;
}
return closestAddr;
}
static Atom::Scope atomScope(uint8_t scope) {
switch (scope) {
case N_EXT:
return Atom::scopeGlobal;
case N_PEXT | N_EXT:
return Atom::scopeLinkageUnit;
case 0:
return Atom::scopeTranslationUnit;
}
llvm_unreachable("unknown scope value!");
}
static void processSymbol(const NormalizedFile &normalizedFile, MachOFile &file,
const Symbol &sym, bool copyRefs) {
// Mach-O symbol table does have size in it, so need to scan ahead
// to find symbol with next highest address.
const Section §ion = normalizedFile.sections[sym.sect - 1];
uint64_t offset = sym.value - section.address;
uint64_t size = nextSymbolAddress(normalizedFile, sym) - sym.value;
ArrayRef<uint8_t> atomContent = section.content.slice(offset, size);
file.addDefinedAtom(sym.name, atomContent, atomScope(sym.scope), copyRefs);
}
static ErrorOr<std::unique_ptr<lld::File>>
normalizedObjectToAtoms(const NormalizedFile &normalizedFile, StringRef path,
bool copyRefs) {
std::unique_ptr<MachOFile> file(new MachOFile(path));
for (const Symbol &sym : normalizedFile.globalSymbols) {
processSymbol(normalizedFile, *file, sym, copyRefs);
}
for (const Symbol &sym : normalizedFile.localSymbols) {
processSymbol(normalizedFile, *file, sym, copyRefs);
}
assert(normalizedFile.undefinedSymbols.empty() &&
"undefined symbols not supported yet!");
return std::unique_ptr<File>(std::move(file));
}
ErrorOr<std::unique_ptr<lld::File>>
normalizedToAtoms(const NormalizedFile &normalizedFile, StringRef path,
bool copyRefs) {
switch (normalizedFile.fileType) {
case MH_OBJECT:
return normalizedObjectToAtoms(normalizedFile, path, copyRefs);
default:
llvm_unreachable("unhandled MachO file type!");
}
}
} // namespace normalized
} // namespace mach_o
} // namespace lld
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