From 25a0d3dd64e4c0873036140587f48ec00893f9f2 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@google.com>
Date: Fri, 3 Apr 2015 22:12:18 +0000
Subject: [PATCH] ELF: Merge ELF{Object,DSO}Reader implementations.

The two classes are the same other than a few exceptions.
This patch merges them using templates.

llvm-svn: 234060
---
 lld/lib/ReaderWriter/ELF/ELFReader.h | 55 ++++++----------------------
 1 file changed, 12 insertions(+), 43 deletions(-)

diff --git a/lld/lib/ReaderWriter/ELF/ELFReader.h b/lld/lib/ReaderWriter/ELF/ELFReader.h
index ad16a09b8ce1..657cd9d0a807 100644
--- a/lld/lib/ReaderWriter/ELF/ELFReader.h
+++ b/lld/lib/ReaderWriter/ELF/ELFReader.h
@@ -18,17 +18,17 @@
 namespace lld {
 namespace elf {
 
-template <typename ELFT, typename ContextT, template <typename> class FileT>
-class ELFObjectReader : public Reader {
+template <typename ELFT, typename ContextT, template <typename> class FileT,
+          int FileMagic>
+class ELFReader : public Reader {
 public:
   typedef llvm::object::Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
 
-  ELFObjectReader(ContextT &ctx) : _ctx(ctx) {}
+  ELFReader(ContextT &ctx) : _ctx(ctx) {}
 
   bool canParse(file_magic magic, StringRef,
                 const MemoryBuffer &buf) const override {
-    return (magic == llvm::sys::fs::file_magic::elf_relocatable &&
-            elfHeader(buf)->e_machine == ContextT::machine);
+    return magic == FileMagic && elfHeader(buf)->e_machine == ContextT::machine;
   }
 
   std::error_code
@@ -45,51 +45,20 @@ public:
   }
 
   const Elf_Ehdr *elfHeader(const MemoryBuffer &buf) const {
-    const uint8_t *data =
-        reinterpret_cast<const uint8_t *>(buf.getBuffer().data());
-    return (reinterpret_cast<const Elf_Ehdr *>(data));
+    return reinterpret_cast<const Elf_Ehdr *>(buf.getBuffer().data());
   }
 
 protected:
   ContextT &_ctx;
 };
 
+template <typename ELFT, typename ContextT, template <typename> class FileT>
+using ELFObjectReader = ELFReader<ELFT, ContextT, FileT,
+                                  llvm::sys::fs::file_magic::elf_relocatable>;
+
 template <typename ELFT, typename ContextT>
-class ELFDSOReader : public Reader {
-public:
-  typedef llvm::object::Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
-
-  ELFDSOReader(ContextT &ctx) : _ctx(ctx) {}
-
-  bool canParse(file_magic magic, StringRef,
-                const MemoryBuffer &buf) const override {
-    return (magic == llvm::sys::fs::file_magic::elf_shared_object &&
-            elfHeader(buf)->e_machine == ContextT::machine);
-  }
-
-  std::error_code
-  loadFile(std::unique_ptr<MemoryBuffer> mb, const class Registry &,
-           std::vector<std::unique_ptr<File>> &result) const override {
-    std::size_t maxAlignment =
-        1ULL << llvm::countTrailingZeros(uintptr_t(mb->getBufferStart()));
-    auto f =
-        createELF<DynamicFile>(llvm::object::getElfArchType(mb->getBuffer()),
-                               maxAlignment, std::move(mb), _ctx);
-    if (std::error_code ec = f.getError())
-      return ec;
-    result.push_back(std::move(*f));
-    return std::error_code();
-  }
-
-  const Elf_Ehdr *elfHeader(const MemoryBuffer &buf) const {
-    const uint8_t *data =
-        reinterpret_cast<const uint8_t *>(buf.getBuffer().data());
-    return (reinterpret_cast<const Elf_Ehdr *>(data));
-  }
-
-protected:
-  ContextT &_ctx;
-};
+using ELFDSOReader = ELFReader<ELFT, ContextT, DynamicFile,
+                               llvm::sys::fs::file_magic::elf_shared_object>;
 
 } // namespace elf
 } // namespace lld