1 files changed, 146 insertions, 0 deletions
diff --git a/lib/ReaderWriter/ELF/DynamicFile.cpp b/lib/ReaderWriter/ELF/DynamicFile.cpp
new file mode 100644
index 0000000000000..5339c7d66577e
--- /dev/null
+++ b/lib/ReaderWriter/ELF/DynamicFile.cpp
@@ -0,0 +1,146 @@
+//===- lib/ReaderWriter/ELF/DynamicFile.cpp -------------------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DynamicFile.h"
+#include "FileCommon.h"
+#include "lld/ReaderWriter/ELFLinkingContext.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Object/ELF.h"
+#include "llvm/Support/Path.h"
+
+namespace lld {
+namespace elf {
+
+template <class ELFT>
+DynamicFile<ELFT>::DynamicFile(std::unique_ptr<MemoryBuffer> mb,
+                               ELFLinkingContext &ctx)
+    : SharedLibraryFile(mb->getBufferIdentifier()), _mb(std::move(mb)),
+      _ctx(ctx), _useShlibUndefines(ctx.useShlibUndefines()) {}
+
+template <typename ELFT>
+std::error_code DynamicFile<ELFT>::isCompatible(MemoryBufferRef mb,
+                                                ELFLinkingContext &ctx) {
+  return elf::isCompatible<ELFT>(mb, ctx);
+}
+
+template <class ELFT>
+const SharedLibraryAtom *DynamicFile<ELFT>::exports(StringRef name,
+                                                    bool dataSymbolOnly) const {
+  assert(!dataSymbolOnly && "Invalid option for ELF exports!");
+  // See if we have the symbol.
+  auto sym = _nameToSym.find(name);
+  if (sym == _nameToSym.end())
+    return nullptr;
+  // Have we already created a SharedLibraryAtom for it?
+  if (sym->second._atom)
+    return sym->second._atom;
+  // Create a SharedLibraryAtom for this symbol.
+  return sym->second._atom = new (_alloc)
+             ELFDynamicAtom<ELFT>(*this, name, _soname, sym->second._symbol);
+}
+
+template <class ELFT> StringRef DynamicFile<ELFT>::getDSOName() const {
+  return _soname;
+}
+
+template <class ELFT> bool DynamicFile<ELFT>::canParse(file_magic magic) {
+  return magic == file_magic::elf_shared_object;
+}
+
+template <class ELFT> std::error_code DynamicFile<ELFT>::doParse() {
+  typedef llvm::object::ELFFile<ELFT> ELFO;
+  typedef typename ELFO::Elf_Shdr Elf_Shdr;
+  typedef typename ELFO::Elf_Dyn Elf_Dyn;
+
+  std::error_code ec;
+  _objFile.reset(new ELFO(_mb->getBuffer(), ec));
+  if (ec)
+    return ec;
+
+  ELFO &obj = *_objFile;
+
+  const char *base = _mb->getBuffer().data();
+  const Elf_Dyn *dynStart = nullptr;
+  const Elf_Dyn *dynEnd = nullptr;
+
+  const Elf_Shdr *dynSymSec = nullptr;
+  for (const Elf_Shdr &sec : obj.sections()) {
+    switch (sec.sh_type) {
+    case llvm::ELF::SHT_DYNAMIC: {
+      dynStart = reinterpret_cast<const Elf_Dyn *>(base + sec.sh_offset);
+      uint64_t size = sec.sh_size;
+      if (size % sizeof(Elf_Dyn))
+        return llvm::object::object_error::parse_failed;
+      dynEnd = dynStart + size / sizeof(Elf_Dyn);
+      break;
+    }
+    case llvm::ELF::SHT_DYNSYM:
+      dynSymSec = &sec;
+      break;
+    }
+  }
+
+  ErrorOr<StringRef> strTableOrErr = obj.getStringTableForSymtab(*dynSymSec);
+  if (std::error_code ec = strTableOrErr.getError())
+    return ec;
+  StringRef stringTable = *strTableOrErr;
+
+  for (const Elf_Dyn &dyn : llvm::make_range(dynStart, dynEnd)) {
+    if (dyn.d_tag == llvm::ELF::DT_SONAME) {
+      uint64_t offset = dyn.getVal();
+      if (offset >= stringTable.size())
+        return llvm::object::object_error::parse_failed;
+      _soname = StringRef(stringTable.data() + offset);
+      break;
+    }
+  }
+
+  if (_soname.empty())
+    _soname = llvm::sys::path::filename(path());
+
+  // Create a map from names to dynamic symbol table entries.
+  // TODO: This should use the object file's build in hash table instead if
+  // it exists.
+  for (auto i = obj.symbol_begin(dynSymSec), e = obj.symbol_end(dynSymSec);
+       i != e; ++i) {
+    auto name = i->getName(stringTable);
+    if ((ec = name.getError()))
+      return ec;
+
+    // Dont add local symbols to dynamic entries. The first symbol in the
+    // dynamic symbol table is a local symbol.
+    if (i->getBinding() == llvm::ELF::STB_LOCAL)
+      continue;
+
+    // TODO: Add absolute symbols
+    if (i->st_shndx == llvm::ELF::SHN_ABS)
+      continue;
+
+    if (i->st_shndx == llvm::ELF::SHN_UNDEF) {
+      if (!_useShlibUndefines)
+        continue;
+      // Create an undefined atom.
+      if (!name->empty()) {
+        auto *newAtom = new (_alloc) ELFUndefinedAtom<ELFT>(*this, *name, &*i);
+        _undefinedAtoms.push_back(newAtom);
+      }
+      continue;
+    }
+    _nameToSym[*name]._symbol = &*i;
+  }
+  return std::error_code();
+}
+
+template class DynamicFile<ELF32LE>;
+template class DynamicFile<ELF32BE>;
+template class DynamicFile<ELF64LE>;
+template class DynamicFile<ELF64BE>;
+
+} // end namespace elf
+} // end namespace lld