forked from OSchip/llvm-project
891 lines
35 KiB
C++
891 lines
35 KiB
C++
//===- InputFiles.cpp -----------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains functions to parse Mach-O object files. In this comment,
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// we describe the Mach-O file structure and how we parse it.
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//
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// Mach-O is not very different from ELF or COFF. The notion of symbols,
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// sections and relocations exists in Mach-O as it does in ELF and COFF.
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//
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// Perhaps the notion that is new to those who know ELF/COFF is "subsections".
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// In ELF/COFF, sections are an atomic unit of data copied from input files to
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// output files. When we merge or garbage-collect sections, we treat each
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// section as an atomic unit. In Mach-O, that's not the case. Sections can
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// consist of multiple subsections, and subsections are a unit of merging and
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// garbage-collecting. Therefore, Mach-O's subsections are more similar to
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// ELF/COFF's sections than Mach-O's sections are.
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//
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// A section can have multiple symbols. A symbol that does not have the
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// N_ALT_ENTRY attribute indicates a beginning of a subsection. Therefore, by
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// definition, a symbol is always present at the beginning of each subsection. A
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// symbol with N_ALT_ENTRY attribute does not start a new subsection and can
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// point to a middle of a subsection.
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//
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// The notion of subsections also affects how relocations are represented in
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// Mach-O. All references within a section need to be explicitly represented as
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// relocations if they refer to different subsections, because we obviously need
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// to fix up addresses if subsections are laid out in an output file differently
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// than they were in object files. To represent that, Mach-O relocations can
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// refer to an unnamed location via its address. Scattered relocations (those
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// with the R_SCATTERED bit set) always refer to unnamed locations.
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// Non-scattered relocations refer to an unnamed location if r_extern is not set
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// and r_symbolnum is zero.
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//
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// Without the above differences, I think you can use your knowledge about ELF
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// and COFF for Mach-O.
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//
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//===----------------------------------------------------------------------===//
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#include "InputFiles.h"
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#include "Config.h"
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#include "Driver.h"
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#include "Dwarf.h"
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#include "ExportTrie.h"
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#include "InputSection.h"
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#include "MachOStructs.h"
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#include "ObjC.h"
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#include "OutputSection.h"
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#include "OutputSegment.h"
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#include "SymbolTable.h"
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#include "Symbols.h"
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#include "Target.h"
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#include "lld/Common/DWARF.h"
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#include "lld/Common/ErrorHandler.h"
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#include "lld/Common/Memory.h"
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#include "lld/Common/Reproduce.h"
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#include "llvm/ADT/iterator.h"
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#include "llvm/BinaryFormat/MachO.h"
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#include "llvm/LTO/LTO.h"
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#include "llvm/Support/Endian.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/TarWriter.h"
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#include "llvm/TextAPI/MachO/Architecture.h"
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#include "llvm/TextAPI/MachO/InterfaceFile.h"
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using namespace llvm;
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using namespace llvm::MachO;
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using namespace llvm::support::endian;
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using namespace llvm::sys;
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using namespace lld;
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using namespace lld::macho;
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// Returns "<internal>", "foo.a(bar.o)", or "baz.o".
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std::string lld::toString(const InputFile *f) {
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if (!f)
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return "<internal>";
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// Multiple dylibs can be defined in one .tbd file.
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if (auto dylibFile = dyn_cast<DylibFile>(f))
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if (f->getName().endswith(".tbd"))
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return (f->getName() + "(" + dylibFile->dylibName + ")").str();
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if (f->archiveName.empty())
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return std::string(f->getName());
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return (path::filename(f->archiveName) + "(" + path::filename(f->getName()) +
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")")
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.str();
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}
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SetVector<InputFile *> macho::inputFiles;
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std::unique_ptr<TarWriter> macho::tar;
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int InputFile::idCount = 0;
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// Open a given file path and return it as a memory-mapped file.
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Optional<MemoryBufferRef> macho::readFile(StringRef path) {
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// Open a file.
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ErrorOr<std::unique_ptr<MemoryBuffer>> mbOrErr = MemoryBuffer::getFile(path);
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if (std::error_code ec = mbOrErr.getError()) {
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error("cannot open " + path + ": " + ec.message());
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return None;
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}
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std::unique_ptr<MemoryBuffer> &mb = *mbOrErr;
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MemoryBufferRef mbref = mb->getMemBufferRef();
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make<std::unique_ptr<MemoryBuffer>>(std::move(mb)); // take mb ownership
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// If this is a regular non-fat file, return it.
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const char *buf = mbref.getBufferStart();
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const auto *hdr = reinterpret_cast<const fat_header *>(buf);
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if (mbref.getBufferSize() < sizeof(uint32_t) ||
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read32be(&hdr->magic) != FAT_MAGIC) {
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if (tar)
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tar->append(relativeToRoot(path), mbref.getBuffer());
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return mbref;
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}
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// Object files and archive files may be fat files, which contains
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// multiple real files for different CPU ISAs. Here, we search for a
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// file that matches with the current link target and returns it as
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// a MemoryBufferRef.
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const auto *arch = reinterpret_cast<const fat_arch *>(buf + sizeof(*hdr));
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for (uint32_t i = 0, n = read32be(&hdr->nfat_arch); i < n; ++i) {
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if (reinterpret_cast<const char *>(arch + i + 1) >
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buf + mbref.getBufferSize()) {
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error(path + ": fat_arch struct extends beyond end of file");
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return None;
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}
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if (read32be(&arch[i].cputype) != target->cpuType ||
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read32be(&arch[i].cpusubtype) != target->cpuSubtype)
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continue;
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uint32_t offset = read32be(&arch[i].offset);
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uint32_t size = read32be(&arch[i].size);
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if (offset + size > mbref.getBufferSize())
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error(path + ": slice extends beyond end of file");
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if (tar)
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tar->append(relativeToRoot(path), mbref.getBuffer());
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return MemoryBufferRef(StringRef(buf + offset, size), path.copy(bAlloc));
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}
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error("unable to find matching architecture in " + path);
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return None;
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}
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InputFile::InputFile(Kind kind, const InterfaceFile &interface)
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: id(idCount++), fileKind(kind), name(saver.save(interface.getPath())) {}
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void ObjFile::parseSections(ArrayRef<section_64> sections) {
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subsections.reserve(sections.size());
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auto *buf = reinterpret_cast<const uint8_t *>(mb.getBufferStart());
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for (const section_64 &sec : sections) {
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InputSection *isec = make<InputSection>();
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isec->file = this;
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isec->name =
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StringRef(sec.sectname, strnlen(sec.sectname, sizeof(sec.sectname)));
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isec->segname =
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StringRef(sec.segname, strnlen(sec.segname, sizeof(sec.segname)));
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isec->data = {isZeroFill(sec.flags) ? nullptr : buf + sec.offset,
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static_cast<size_t>(sec.size)};
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if (sec.align >= 32)
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error("alignment " + std::to_string(sec.align) + " of section " +
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isec->name + " is too large");
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else
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isec->align = 1 << sec.align;
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isec->flags = sec.flags;
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if (!(isDebugSection(isec->flags) &&
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isec->segname == segment_names::dwarf)) {
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subsections.push_back({{0, isec}});
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} else {
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// Instead of emitting DWARF sections, we emit STABS symbols to the
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// object files that contain them. We filter them out early to avoid
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// parsing their relocations unnecessarily. But we must still push an
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// empty map to ensure the indices line up for the remaining sections.
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subsections.push_back({});
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debugSections.push_back(isec);
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}
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}
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}
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// Find the subsection corresponding to the greatest section offset that is <=
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// that of the given offset.
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//
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// offset: an offset relative to the start of the original InputSection (before
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// any subsection splitting has occurred). It will be updated to represent the
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// same location as an offset relative to the start of the containing
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// subsection.
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static InputSection *findContainingSubsection(SubsectionMapping &map,
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uint64_t *offset) {
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auto it = std::prev(llvm::upper_bound(
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map, *offset, [](uint64_t value, SubsectionEntry subsectionEntry) {
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return value < subsectionEntry.offset;
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}));
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*offset -= it->offset;
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return it->isec;
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}
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static bool validateRelocationInfo(InputFile *file, const section_64 &sec,
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relocation_info rel) {
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const RelocAttrs &relocAttrs = target->getRelocAttrs(rel.r_type);
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bool valid = true;
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auto message = [relocAttrs, file, sec, rel, &valid](const Twine &diagnostic) {
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valid = false;
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return (relocAttrs.name + " relocation " + diagnostic + " at offset " +
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std::to_string(rel.r_address) + " of " + sec.segname + "," +
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sec.sectname + " in " + toString(file))
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.str();
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};
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if (!relocAttrs.hasAttr(RelocAttrBits::LOCAL) && !rel.r_extern)
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error(message("must be extern"));
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if (relocAttrs.hasAttr(RelocAttrBits::PCREL) != rel.r_pcrel)
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error(message(Twine("must ") + (rel.r_pcrel ? "not " : "") +
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"be PC-relative"));
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if (isThreadLocalVariables(sec.flags) &&
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!relocAttrs.hasAttr(RelocAttrBits::UNSIGNED))
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error(message("not allowed in thread-local section, must be UNSIGNED"));
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if (rel.r_length < 2 || rel.r_length > 3 ||
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!relocAttrs.hasAttr(static_cast<RelocAttrBits>(1 << rel.r_length))) {
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static SmallVector<StringRef, 4> widths{"0", "4", "8", "4 or 8"};
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error(message("has width " + std::to_string(1 << rel.r_length) +
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" bytes, but must be " +
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widths[(static_cast<int>(relocAttrs.bits) >> 2) & 3] +
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" bytes"));
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}
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return valid;
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}
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void ObjFile::parseRelocations(const section_64 &sec,
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SubsectionMapping &subsecMap) {
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auto *buf = reinterpret_cast<const uint8_t *>(mb.getBufferStart());
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ArrayRef<relocation_info> relInfos(
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reinterpret_cast<const relocation_info *>(buf + sec.reloff), sec.nreloc);
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for (size_t i = 0; i < relInfos.size(); i++) {
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// Paired relocations serve as Mach-O's method for attaching a
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// supplemental datum to a primary relocation record. ELF does not
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// need them because the *_RELOC_RELA records contain the extra
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// addend field, vs. *_RELOC_REL which omit the addend.
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//
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// The {X86_64,ARM64}_RELOC_SUBTRACTOR record holds the subtrahend,
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// and the paired *_RELOC_UNSIGNED record holds the minuend. The
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// datum for each is a symbolic address. The result is the offset
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// between two addresses.
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//
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// The ARM64_RELOC_ADDEND record holds the addend, and the paired
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// ARM64_RELOC_BRANCH26 or ARM64_RELOC_PAGE21/PAGEOFF12 holds the
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// base symbolic address.
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//
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// Note: X86 does not use *_RELOC_ADDEND because it can embed an
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// addend into the instruction stream. On X86, a relocatable address
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// field always occupies an entire contiguous sequence of byte(s),
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// so there is no need to merge opcode bits with address
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// bits. Therefore, it's easy and convenient to store addends in the
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// instruction-stream bytes that would otherwise contain zeroes. By
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// contrast, RISC ISAs such as ARM64 mix opcode bits with with
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// address bits so that bitwise arithmetic is necessary to extract
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// and insert them. Storing addends in the instruction stream is
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// possible, but inconvenient and more costly at link time.
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int64_t pairedAddend = 0;
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relocation_info relInfo = relInfos[i];
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if (target->hasAttr(relInfo.r_type, RelocAttrBits::ADDEND)) {
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pairedAddend = SignExtend64<24>(relInfo.r_symbolnum);
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relInfo = relInfos[++i];
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}
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assert(i < relInfos.size());
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if (!validateRelocationInfo(this, sec, relInfo))
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continue;
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if (relInfo.r_address & R_SCATTERED)
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fatal("TODO: Scattered relocations not supported");
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int64_t embeddedAddend = target->getEmbeddedAddend(mb, sec, relInfo);
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assert(!(embeddedAddend && pairedAddend));
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int64_t totalAddend = pairedAddend + embeddedAddend;
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Reloc r;
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r.type = relInfo.r_type;
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r.pcrel = relInfo.r_pcrel;
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r.length = relInfo.r_length;
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r.offset = relInfo.r_address;
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if (relInfo.r_extern) {
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r.referent = symbols[relInfo.r_symbolnum];
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r.addend = totalAddend;
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} else {
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SubsectionMapping &referentSubsecMap =
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subsections[relInfo.r_symbolnum - 1];
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const section_64 &referentSec = sectionHeaders[relInfo.r_symbolnum - 1];
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uint64_t referentOffset;
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if (relInfo.r_pcrel) {
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// The implicit addend for pcrel section relocations is the pcrel offset
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// in terms of the addresses in the input file. Here we adjust it so
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// that it describes the offset from the start of the referent section.
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// FIXME This logic was written around x86_64 behavior -- ARM64 doesn't
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// have pcrel section relocations. We may want to factor this out into
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// the arch-specific .cpp file.
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assert(target->hasAttr(r.type, RelocAttrBits::BYTE4));
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referentOffset =
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sec.addr + relInfo.r_address + 4 + totalAddend - referentSec.addr;
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} else {
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// The addend for a non-pcrel relocation is its absolute address.
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referentOffset = totalAddend - referentSec.addr;
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}
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r.referent = findContainingSubsection(referentSubsecMap, &referentOffset);
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r.addend = referentOffset;
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}
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InputSection *subsec = findContainingSubsection(subsecMap, &r.offset);
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subsec->relocs.push_back(r);
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if (target->hasAttr(r.type, RelocAttrBits::SUBTRAHEND)) {
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relInfo = relInfos[++i];
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// SUBTRACTOR relocations should always be followed by an UNSIGNED one
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// indicating the minuend symbol.
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assert(target->hasAttr(relInfo.r_type, RelocAttrBits::UNSIGNED) &&
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relInfo.r_extern);
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Reloc p;
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p.type = relInfo.r_type;
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p.referent = symbols[relInfo.r_symbolnum];
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subsec->relocs.push_back(p);
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}
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}
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}
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static macho::Symbol *createDefined(const structs::nlist_64 &sym,
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StringRef name, InputSection *isec,
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uint64_t value, uint64_t size) {
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// Symbol scope is determined by sym.n_type & (N_EXT | N_PEXT):
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// N_EXT: Global symbols
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// N_EXT | N_PEXT: Linkage unit (think: dylib) scoped
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// N_PEXT: Does not occur in input files in practice,
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// a private extern must be external.
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// 0: Translation-unit scoped. These are not in the symbol table.
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if (sym.n_type & (N_EXT | N_PEXT)) {
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assert((sym.n_type & N_EXT) && "invalid input");
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return symtab->addDefined(name, isec->file, isec, value, size,
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sym.n_desc & N_WEAK_DEF, sym.n_type & N_PEXT);
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}
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return make<Defined>(name, isec->file, isec, value, size,
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sym.n_desc & N_WEAK_DEF,
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/*isExternal=*/false, /*isPrivateExtern=*/false);
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}
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// Checks if the version specified in `cmd` is compatible with target
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// version. IOW, check if cmd's version >= config's version.
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static bool hasCompatVersion(const InputFile *input,
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const build_version_command *cmd) {
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if (config->target.Platform != static_cast<PlatformKind>(cmd->platform)) {
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error(toString(input) + " has platform " +
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getPlatformName(static_cast<PlatformKind>(cmd->platform)) +
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Twine(", which is different from target platform ") +
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getPlatformName(config->target.Platform));
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return false;
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}
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unsigned major = cmd->minos >> 16;
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unsigned minor = (cmd->minos >> 8) & 0xffu;
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unsigned subMinor = cmd->minos & 0xffu;
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VersionTuple version(major, minor, subMinor);
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if (version >= config->platformInfo.minimum)
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return true;
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error(toString(input) + " has version " + version.getAsString() +
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", which is incompatible with target version of " +
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config->platformInfo.minimum.getAsString());
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return false;
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}
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// Absolute symbols are defined symbols that do not have an associated
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// InputSection. They cannot be weak.
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static macho::Symbol *createAbsolute(const structs::nlist_64 &sym,
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InputFile *file, StringRef name) {
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if (sym.n_type & (N_EXT | N_PEXT)) {
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assert((sym.n_type & N_EXT) && "invalid input");
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return symtab->addDefined(name, file, nullptr, sym.n_value, /*size=*/0,
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/*isWeakDef=*/false, sym.n_type & N_PEXT);
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}
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return make<Defined>(name, file, nullptr, sym.n_value, /*size=*/0,
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/*isWeakDef=*/false,
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/*isExternal=*/false, /*isPrivateExtern=*/false);
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}
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macho::Symbol *ObjFile::parseNonSectionSymbol(const structs::nlist_64 &sym,
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StringRef name) {
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uint8_t type = sym.n_type & N_TYPE;
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switch (type) {
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case N_UNDF:
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return sym.n_value == 0
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? symtab->addUndefined(name, this, sym.n_desc & N_WEAK_REF)
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: symtab->addCommon(name, this, sym.n_value,
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1 << GET_COMM_ALIGN(sym.n_desc),
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sym.n_type & N_PEXT);
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case N_ABS:
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return createAbsolute(sym, this, name);
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case N_PBUD:
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case N_INDR:
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error("TODO: support symbols of type " + std::to_string(type));
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return nullptr;
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case N_SECT:
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llvm_unreachable(
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"N_SECT symbols should not be passed to parseNonSectionSymbol");
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default:
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llvm_unreachable("invalid symbol type");
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}
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}
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void ObjFile::parseSymbols(ArrayRef<structs::nlist_64> nList,
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const char *strtab, bool subsectionsViaSymbols) {
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// Precompute the boundaries of symbols within a section.
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// If subsectionsViaSymbols is True then the corresponding subsections will be
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// created, otherwise these boundaries are used for the calculation of symbols
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// sizes only.
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for (const structs::nlist_64 &sym : nList) {
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if ((sym.n_type & N_TYPE) == N_SECT && !(sym.n_desc & N_ALT_ENTRY) &&
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!subsections[sym.n_sect - 1].empty()) {
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SubsectionMapping &subsectionMapping = subsections[sym.n_sect - 1];
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subsectionMapping.push_back(
|
|
{sym.n_value - sectionHeaders[sym.n_sect - 1].addr,
|
|
subsectionMapping.front().isec});
|
|
}
|
|
}
|
|
|
|
for (SubsectionMapping &subsectionMap : subsections) {
|
|
if (subsectionMap.empty())
|
|
continue;
|
|
llvm::sort(subsectionMap,
|
|
[](const SubsectionEntry &lhs, const SubsectionEntry &rhs) {
|
|
return lhs.offset < rhs.offset;
|
|
});
|
|
subsectionMap.erase(
|
|
std::unique(subsectionMap.begin(), subsectionMap.end(),
|
|
[](const SubsectionEntry &lhs, const SubsectionEntry &rhs) {
|
|
return lhs.offset == rhs.offset;
|
|
}),
|
|
subsectionMap.end());
|
|
if (!subsectionsViaSymbols)
|
|
continue;
|
|
for (size_t i = 0; i < subsectionMap.size(); ++i) {
|
|
uint32_t offset = subsectionMap[i].offset;
|
|
InputSection *&isec = subsectionMap[i].isec;
|
|
uint32_t end = i + 1 < subsectionMap.size() ? subsectionMap[i + 1].offset
|
|
: isec->data.size();
|
|
isec = make<InputSection>(*isec);
|
|
isec->data = isec->data.slice(offset, end - offset);
|
|
// TODO: ld64 appears to preserve the original alignment as well as each
|
|
// subsection's offset from the last aligned address. We should consider
|
|
// emulating that behavior.
|
|
isec->align = MinAlign(isec->align, offset);
|
|
}
|
|
}
|
|
|
|
symbols.resize(nList.size());
|
|
for (size_t i = 0, n = nList.size(); i < n; ++i) {
|
|
const structs::nlist_64 &sym = nList[i];
|
|
StringRef name = strtab + sym.n_strx;
|
|
|
|
if ((sym.n_type & N_TYPE) != N_SECT) {
|
|
symbols[i] = parseNonSectionSymbol(sym, name);
|
|
continue;
|
|
}
|
|
|
|
const section_64 &sec = sectionHeaders[sym.n_sect - 1];
|
|
SubsectionMapping &subsecMap = subsections[sym.n_sect - 1];
|
|
|
|
// parseSections() may have chosen not to parse this section.
|
|
if (subsecMap.empty())
|
|
continue;
|
|
|
|
uint64_t offset = sym.n_value - sec.addr;
|
|
|
|
auto it = llvm::upper_bound(
|
|
subsecMap, offset, [](int64_t value, SubsectionEntry subsectionEntry) {
|
|
return value < subsectionEntry.offset;
|
|
});
|
|
uint32_t size = it != subsecMap.end()
|
|
? it->offset - offset
|
|
: subsecMap.front().isec->getSize() - offset;
|
|
|
|
// If the input file does not use subsections-via-symbols, all symbols can
|
|
// use the same subsection. Otherwise, we must split the sections along
|
|
// symbol boundaries.
|
|
if (!subsectionsViaSymbols) {
|
|
symbols[i] =
|
|
createDefined(sym, name, subsecMap.front().isec, offset, size);
|
|
continue;
|
|
}
|
|
|
|
InputSection *subsec = (--it)->isec;
|
|
symbols[i] = createDefined(sym, name, subsec, offset - it->offset, size);
|
|
}
|
|
|
|
if (!subsectionsViaSymbols)
|
|
for (SubsectionMapping &subsectionMap : subsections)
|
|
if (!subsectionMap.empty())
|
|
subsectionMap = {subsectionMap.front()};
|
|
}
|
|
|
|
OpaqueFile::OpaqueFile(MemoryBufferRef mb, StringRef segName,
|
|
StringRef sectName)
|
|
: InputFile(OpaqueKind, mb) {
|
|
InputSection *isec = make<InputSection>();
|
|
isec->file = this;
|
|
isec->name = sectName.take_front(16);
|
|
isec->segname = segName.take_front(16);
|
|
const auto *buf = reinterpret_cast<const uint8_t *>(mb.getBufferStart());
|
|
isec->data = {buf, mb.getBufferSize()};
|
|
subsections.push_back({{0, isec}});
|
|
}
|
|
|
|
ObjFile::ObjFile(MemoryBufferRef mb, uint32_t modTime, StringRef archiveName)
|
|
: InputFile(ObjKind, mb), modTime(modTime) {
|
|
this->archiveName = std::string(archiveName);
|
|
|
|
auto *buf = reinterpret_cast<const uint8_t *>(mb.getBufferStart());
|
|
auto *hdr = reinterpret_cast<const mach_header_64 *>(mb.getBufferStart());
|
|
|
|
Architecture arch = getArchitectureFromCpuType(hdr->cputype, hdr->cpusubtype);
|
|
if (arch != config->target.Arch) {
|
|
error(toString(this) + " has architecture " + getArchitectureName(arch) +
|
|
" which is incompatible with target architecture " +
|
|
getArchitectureName(config->target.Arch));
|
|
return;
|
|
}
|
|
|
|
if (const auto *cmd =
|
|
findCommand<build_version_command>(hdr, LC_BUILD_VERSION)) {
|
|
if (!hasCompatVersion(this, cmd))
|
|
return;
|
|
}
|
|
|
|
if (const load_command *cmd = findCommand(hdr, LC_LINKER_OPTION)) {
|
|
auto *c = reinterpret_cast<const linker_option_command *>(cmd);
|
|
StringRef data{reinterpret_cast<const char *>(c + 1),
|
|
c->cmdsize - sizeof(linker_option_command)};
|
|
parseLCLinkerOption(this, c->count, data);
|
|
}
|
|
|
|
if (const load_command *cmd = findCommand(hdr, LC_SEGMENT_64)) {
|
|
auto *c = reinterpret_cast<const segment_command_64 *>(cmd);
|
|
sectionHeaders = ArrayRef<section_64>{
|
|
reinterpret_cast<const section_64 *>(c + 1), c->nsects};
|
|
parseSections(sectionHeaders);
|
|
}
|
|
|
|
// TODO: Error on missing LC_SYMTAB?
|
|
if (const load_command *cmd = findCommand(hdr, LC_SYMTAB)) {
|
|
auto *c = reinterpret_cast<const symtab_command *>(cmd);
|
|
ArrayRef<structs::nlist_64> nList(
|
|
reinterpret_cast<const structs::nlist_64 *>(buf + c->symoff), c->nsyms);
|
|
const char *strtab = reinterpret_cast<const char *>(buf) + c->stroff;
|
|
bool subsectionsViaSymbols = hdr->flags & MH_SUBSECTIONS_VIA_SYMBOLS;
|
|
parseSymbols(nList, strtab, subsectionsViaSymbols);
|
|
}
|
|
|
|
// The relocations may refer to the symbols, so we parse them after we have
|
|
// parsed all the symbols.
|
|
for (size_t i = 0, n = subsections.size(); i < n; ++i)
|
|
if (!subsections[i].empty())
|
|
parseRelocations(sectionHeaders[i], subsections[i]);
|
|
|
|
parseDebugInfo();
|
|
}
|
|
|
|
void ObjFile::parseDebugInfo() {
|
|
std::unique_ptr<DwarfObject> dObj = DwarfObject::create(this);
|
|
if (!dObj)
|
|
return;
|
|
|
|
auto *ctx = make<DWARFContext>(
|
|
std::move(dObj), "",
|
|
[&](Error err) {
|
|
warn(toString(this) + ": " + toString(std::move(err)));
|
|
},
|
|
[&](Error warning) {
|
|
warn(toString(this) + ": " + toString(std::move(warning)));
|
|
});
|
|
|
|
// TODO: Since object files can contain a lot of DWARF info, we should verify
|
|
// that we are parsing just the info we need
|
|
const DWARFContext::compile_unit_range &units = ctx->compile_units();
|
|
// FIXME: There can be more than one compile unit per object file. See
|
|
// PR48637.
|
|
auto it = units.begin();
|
|
compileUnit = it->get();
|
|
}
|
|
|
|
// The path can point to either a dylib or a .tbd file.
|
|
static Optional<DylibFile *> loadDylib(StringRef path, DylibFile *umbrella) {
|
|
Optional<MemoryBufferRef> mbref = readFile(path);
|
|
if (!mbref) {
|
|
error("could not read dylib file at " + path);
|
|
return {};
|
|
}
|
|
return loadDylib(*mbref, umbrella);
|
|
}
|
|
|
|
// TBD files are parsed into a series of TAPI documents (InterfaceFiles), with
|
|
// the first document storing child pointers to the rest of them. When we are
|
|
// processing a given TBD file, we store that top-level document in
|
|
// currentTopLevelTapi. When processing re-exports, we search its children for
|
|
// potentially matching documents in the same TBD file. Note that the children
|
|
// themselves don't point to further documents, i.e. this is a two-level tree.
|
|
//
|
|
// Re-exports can either refer to on-disk files, or to documents within .tbd
|
|
// files.
|
|
static Optional<DylibFile *>
|
|
findDylib(StringRef path, DylibFile *umbrella,
|
|
const InterfaceFile *currentTopLevelTapi) {
|
|
if (path::is_absolute(path, path::Style::posix))
|
|
for (StringRef root : config->systemLibraryRoots)
|
|
if (Optional<std::string> dylibPath =
|
|
resolveDylibPath((root + path).str()))
|
|
return loadDylib(*dylibPath, umbrella);
|
|
|
|
// TODO: Expand @loader_path, @executable_path, @rpath etc, handle -dylib_path
|
|
|
|
if (currentTopLevelTapi) {
|
|
for (InterfaceFile &child :
|
|
make_pointee_range(currentTopLevelTapi->documents())) {
|
|
assert(child.documents().empty());
|
|
if (path == child.getInstallName())
|
|
return make<DylibFile>(child, umbrella);
|
|
}
|
|
}
|
|
|
|
if (Optional<std::string> dylibPath = resolveDylibPath(path))
|
|
return loadDylib(*dylibPath, umbrella);
|
|
|
|
return {};
|
|
}
|
|
|
|
// If a re-exported dylib is public (lives in /usr/lib or
|
|
// /System/Library/Frameworks), then it is considered implicitly linked: we
|
|
// should bind to its symbols directly instead of via the re-exporting umbrella
|
|
// library.
|
|
static bool isImplicitlyLinked(StringRef path) {
|
|
if (!config->implicitDylibs)
|
|
return false;
|
|
|
|
if (path::parent_path(path) == "/usr/lib")
|
|
return true;
|
|
|
|
// Match /System/Library/Frameworks/$FOO.framework/**/$FOO
|
|
if (path.consume_front("/System/Library/Frameworks/")) {
|
|
StringRef frameworkName = path.take_until([](char c) { return c == '.'; });
|
|
return path::filename(path) == frameworkName;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
void loadReexport(StringRef path, DylibFile *umbrella,
|
|
const InterfaceFile *currentTopLevelTapi) {
|
|
Optional<DylibFile *> reexport =
|
|
findDylib(path, umbrella, currentTopLevelTapi);
|
|
if (!reexport)
|
|
error("unable to locate re-export with install name " + path);
|
|
else if (isImplicitlyLinked(path))
|
|
inputFiles.insert(*reexport);
|
|
}
|
|
|
|
DylibFile::DylibFile(MemoryBufferRef mb, DylibFile *umbrella,
|
|
bool isBundleLoader)
|
|
: InputFile(DylibKind, mb), refState(RefState::Unreferenced),
|
|
isBundleLoader(isBundleLoader) {
|
|
assert(!isBundleLoader || !umbrella);
|
|
if (umbrella == nullptr)
|
|
umbrella = this;
|
|
|
|
auto *buf = reinterpret_cast<const uint8_t *>(mb.getBufferStart());
|
|
auto *hdr = reinterpret_cast<const mach_header_64 *>(mb.getBufferStart());
|
|
|
|
// Initialize dylibName.
|
|
if (const load_command *cmd = findCommand(hdr, LC_ID_DYLIB)) {
|
|
auto *c = reinterpret_cast<const dylib_command *>(cmd);
|
|
currentVersion = read32le(&c->dylib.current_version);
|
|
compatibilityVersion = read32le(&c->dylib.compatibility_version);
|
|
dylibName = reinterpret_cast<const char *>(cmd) + read32le(&c->dylib.name);
|
|
} else if (!isBundleLoader) {
|
|
// macho_executable and macho_bundle don't have LC_ID_DYLIB,
|
|
// so it's OK.
|
|
error("dylib " + toString(this) + " missing LC_ID_DYLIB load command");
|
|
return;
|
|
}
|
|
|
|
if (const build_version_command *cmd =
|
|
findCommand<build_version_command>(hdr, LC_BUILD_VERSION)) {
|
|
if (!hasCompatVersion(this, cmd))
|
|
return;
|
|
}
|
|
|
|
// Initialize symbols.
|
|
DylibFile *exportingFile = isImplicitlyLinked(dylibName) ? this : umbrella;
|
|
if (const load_command *cmd = findCommand(hdr, LC_DYLD_INFO_ONLY)) {
|
|
auto *c = reinterpret_cast<const dyld_info_command *>(cmd);
|
|
parseTrie(buf + c->export_off, c->export_size,
|
|
[&](const Twine &name, uint64_t flags) {
|
|
bool isWeakDef = flags & EXPORT_SYMBOL_FLAGS_WEAK_DEFINITION;
|
|
bool isTlv = flags & EXPORT_SYMBOL_FLAGS_KIND_THREAD_LOCAL;
|
|
symbols.push_back(symtab->addDylib(
|
|
saver.save(name), exportingFile, isWeakDef, isTlv));
|
|
});
|
|
} else {
|
|
error("LC_DYLD_INFO_ONLY not found in " + toString(this));
|
|
return;
|
|
}
|
|
|
|
const uint8_t *p =
|
|
reinterpret_cast<const uint8_t *>(hdr) + sizeof(mach_header_64);
|
|
for (uint32_t i = 0, n = hdr->ncmds; i < n; ++i) {
|
|
auto *cmd = reinterpret_cast<const load_command *>(p);
|
|
p += cmd->cmdsize;
|
|
|
|
if (!(hdr->flags & MH_NO_REEXPORTED_DYLIBS) &&
|
|
cmd->cmd == LC_REEXPORT_DYLIB) {
|
|
const auto *c = reinterpret_cast<const dylib_command *>(cmd);
|
|
StringRef reexportPath =
|
|
reinterpret_cast<const char *>(c) + read32le(&c->dylib.name);
|
|
loadReexport(reexportPath, exportingFile, nullptr);
|
|
}
|
|
|
|
// FIXME: What about LC_LOAD_UPWARD_DYLIB, LC_LAZY_LOAD_DYLIB,
|
|
// LC_LOAD_WEAK_DYLIB, LC_REEXPORT_DYLIB (..are reexports from dylibs with
|
|
// MH_NO_REEXPORTED_DYLIBS loaded for -flat_namespace)?
|
|
if (config->namespaceKind == NamespaceKind::flat &&
|
|
cmd->cmd == LC_LOAD_DYLIB) {
|
|
const auto *c = reinterpret_cast<const dylib_command *>(cmd);
|
|
StringRef dylibPath =
|
|
reinterpret_cast<const char *>(c) + read32le(&c->dylib.name);
|
|
Optional<DylibFile *> dylib = findDylib(dylibPath, umbrella, nullptr);
|
|
if (!dylib)
|
|
error(Twine("unable to locate library '") + dylibPath +
|
|
"' loaded from '" + toString(this) + "' for -flat_namespace");
|
|
}
|
|
}
|
|
}
|
|
|
|
DylibFile::DylibFile(const InterfaceFile &interface, DylibFile *umbrella,
|
|
bool isBundleLoader)
|
|
: InputFile(DylibKind, interface), refState(RefState::Unreferenced),
|
|
isBundleLoader(isBundleLoader) {
|
|
// FIXME: Add test for the missing TBD code path.
|
|
|
|
if (umbrella == nullptr)
|
|
umbrella = this;
|
|
|
|
dylibName = saver.save(interface.getInstallName());
|
|
compatibilityVersion = interface.getCompatibilityVersion().rawValue();
|
|
currentVersion = interface.getCurrentVersion().rawValue();
|
|
|
|
if (!is_contained(interface.targets(), config->target)) {
|
|
error(toString(this) + " is incompatible with " +
|
|
std::string(config->target));
|
|
return;
|
|
}
|
|
|
|
DylibFile *exportingFile = isImplicitlyLinked(dylibName) ? this : umbrella;
|
|
auto addSymbol = [&](const Twine &name) -> void {
|
|
symbols.push_back(symtab->addDylib(saver.save(name), exportingFile,
|
|
/*isWeakDef=*/false,
|
|
/*isTlv=*/false));
|
|
};
|
|
// TODO(compnerd) filter out symbols based on the target platform
|
|
// TODO: handle weak defs, thread locals
|
|
for (const auto *symbol : interface.symbols()) {
|
|
if (!symbol->getArchitectures().has(config->target.Arch))
|
|
continue;
|
|
|
|
switch (symbol->getKind()) {
|
|
case SymbolKind::GlobalSymbol:
|
|
addSymbol(symbol->getName());
|
|
break;
|
|
case SymbolKind::ObjectiveCClass:
|
|
// XXX ld64 only creates these symbols when -ObjC is passed in. We may
|
|
// want to emulate that.
|
|
addSymbol(objc::klass + symbol->getName());
|
|
addSymbol(objc::metaclass + symbol->getName());
|
|
break;
|
|
case SymbolKind::ObjectiveCClassEHType:
|
|
addSymbol(objc::ehtype + symbol->getName());
|
|
break;
|
|
case SymbolKind::ObjectiveCInstanceVariable:
|
|
addSymbol(objc::ivar + symbol->getName());
|
|
break;
|
|
}
|
|
}
|
|
|
|
const InterfaceFile *topLevel =
|
|
interface.getParent() == nullptr ? &interface : interface.getParent();
|
|
|
|
for (InterfaceFileRef intfRef : interface.reexportedLibraries()) {
|
|
InterfaceFile::const_target_range targets = intfRef.targets();
|
|
if (is_contained(targets, config->target))
|
|
loadReexport(intfRef.getInstallName(), exportingFile, topLevel);
|
|
}
|
|
}
|
|
|
|
ArchiveFile::ArchiveFile(std::unique_ptr<object::Archive> &&f)
|
|
: InputFile(ArchiveKind, f->getMemoryBufferRef()), file(std::move(f)) {
|
|
for (const object::Archive::Symbol &sym : file->symbols())
|
|
symtab->addLazy(sym.getName(), this, sym);
|
|
}
|
|
|
|
void ArchiveFile::fetch(const object::Archive::Symbol &sym) {
|
|
object::Archive::Child c =
|
|
CHECK(sym.getMember(), toString(this) +
|
|
": could not get the member for symbol " +
|
|
toMachOString(sym));
|
|
|
|
if (!seen.insert(c.getChildOffset()).second)
|
|
return;
|
|
|
|
MemoryBufferRef mb =
|
|
CHECK(c.getMemoryBufferRef(),
|
|
toString(this) +
|
|
": could not get the buffer for the member defining symbol " +
|
|
toMachOString(sym));
|
|
|
|
if (tar && c.getParent()->isThin())
|
|
tar->append(relativeToRoot(CHECK(c.getFullName(), this)), mb.getBuffer());
|
|
|
|
uint32_t modTime = toTimeT(
|
|
CHECK(c.getLastModified(), toString(this) +
|
|
": could not get the modification time "
|
|
"for the member defining symbol " +
|
|
toMachOString(sym)));
|
|
|
|
// `sym` is owned by a LazySym, which will be replace<>() by make<ObjFile>
|
|
// and become invalid after that call. Copy it to the stack so we can refer
|
|
// to it later.
|
|
const object::Archive::Symbol sym_copy = sym;
|
|
|
|
if (Optional<InputFile *> file =
|
|
loadArchiveMember(mb, modTime, getName(), /*objCOnly=*/false)) {
|
|
inputFiles.insert(*file);
|
|
// ld64 doesn't demangle sym here even with -demangle. Match that, so
|
|
// intentionally no call to toMachOString() here.
|
|
printArchiveMemberLoad(sym_copy.getName(), *file);
|
|
}
|
|
}
|
|
|
|
static macho::Symbol *createBitcodeSymbol(const lto::InputFile::Symbol &objSym,
|
|
BitcodeFile &file) {
|
|
StringRef name = saver.save(objSym.getName());
|
|
|
|
// TODO: support weak references
|
|
if (objSym.isUndefined())
|
|
return symtab->addUndefined(name, &file, /*isWeakRef=*/false);
|
|
|
|
assert(!objSym.isCommon() && "TODO: support common symbols in LTO");
|
|
|
|
// TODO: Write a test demonstrating why computing isPrivateExtern before
|
|
// LTO compilation is important.
|
|
bool isPrivateExtern = false;
|
|
switch (objSym.getVisibility()) {
|
|
case GlobalValue::HiddenVisibility:
|
|
isPrivateExtern = true;
|
|
break;
|
|
case GlobalValue::ProtectedVisibility:
|
|
error(name + " has protected visibility, which is not supported by Mach-O");
|
|
break;
|
|
case GlobalValue::DefaultVisibility:
|
|
break;
|
|
}
|
|
|
|
return symtab->addDefined(name, &file, /*isec=*/nullptr, /*value=*/0,
|
|
/*size=*/0, objSym.isWeak(), isPrivateExtern);
|
|
}
|
|
|
|
BitcodeFile::BitcodeFile(MemoryBufferRef mbref)
|
|
: InputFile(BitcodeKind, mbref) {
|
|
obj = check(lto::InputFile::create(mbref));
|
|
|
|
// Convert LTO Symbols to LLD Symbols in order to perform resolution. The
|
|
// "winning" symbol will then be marked as Prevailing at LTO compilation
|
|
// time.
|
|
for (const lto::InputFile::Symbol &objSym : obj->symbols())
|
|
symbols.push_back(createBitcodeSymbol(objSym, *this));
|
|
}
|