From db9e9d83b61f7f084f235eb87314f673c19c0350 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@google.com>
Date: Sat, 4 Apr 2015 02:07:30 +0000
Subject: [PATCH] ELF: Teach File classes about their file magics.

So that we can remove one template parameter from ELFReader.
ELF port is heavily templatized, and I want to reduce the usage
where possible.

llvm-svn: 234074
---
 lld/lib/ReaderWriter/ELF/DynamicFile.h |  4 ++++
 lld/lib/ReaderWriter/ELF/ELFFile.h     |  5 ++++-
 lld/lib/ReaderWriter/ELF/ELFReader.h   | 12 +++++-------
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/lld/lib/ReaderWriter/ELF/DynamicFile.h b/lld/lib/ReaderWriter/ELF/DynamicFile.h
index 50c37c6..9b2f2c9 100644
--- a/lld/lib/ReaderWriter/ELF/DynamicFile.h
+++ b/lld/lib/ReaderWriter/ELF/DynamicFile.h
@@ -45,6 +45,10 @@ public:
 
   StringRef getDSOName() const override { return _soname; }
 
+  static bool canParse(file_magic magic) {
+    return magic == file_magic::elf_shared_object;
+  }
+
 protected:
   std::error_code doParse() override {
     std::error_code ec;
diff --git a/lld/lib/ReaderWriter/ELF/ELFFile.h b/lld/lib/ReaderWriter/ELF/ELFFile.h
index 4e1654b..1485e53 100644
--- a/lld/lib/ReaderWriter/ELF/ELFFile.h
+++ b/lld/lib/ReaderWriter/ELF/ELFFile.h
@@ -22,7 +22,6 @@ namespace elf {
 /// \brief Read a binary, find out based on the symbol table contents what kind
 /// of symbol it is and create corresponding atoms for it
 template <class ELFT> class ELFFile : public File {
-
   typedef llvm::object::Elf_Sym_Impl<ELFT> Elf_Sym;
   typedef llvm::object::Elf_Shdr_Impl<ELFT> Elf_Shdr;
   typedef llvm::object::Elf_Rel_Impl<ELFT, false> Elf_Rel;
@@ -102,6 +101,10 @@ public:
         _ordinal(0), _doStringsMerge(ctx.mergeCommonStrings()),
         _useWrap(ctx.wrapCalls().size()), _ctx(ctx) {}
 
+  static bool canParse(file_magic magic) {
+    return magic == file_magic::elf_relocatable;
+  }
+
   virtual Reference::KindArch kindArch();
 
   /// \brief Create symbols from LinkingContext.
diff --git a/lld/lib/ReaderWriter/ELF/ELFReader.h b/lld/lib/ReaderWriter/ELF/ELFReader.h
index da1c7ca..04d726b 100644
--- a/lld/lib/ReaderWriter/ELF/ELFReader.h
+++ b/lld/lib/ReaderWriter/ELF/ELFReader.h
@@ -18,8 +18,7 @@
 namespace lld {
 namespace elf {
 
-template <typename ELFT, typename ContextT, template <typename> class FileT,
-          int FileMagic>
+template <typename ELFT, typename ContextT, template <typename> class FileT>
 class ELFReader : public Reader {
 public:
   typedef llvm::object::Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
@@ -28,7 +27,8 @@ public:
 
   bool canParse(file_magic magic, StringRef,
                 const MemoryBuffer &buf) const override {
-    return magic == FileMagic && elfHeader(buf)->e_machine == ContextT::machine;
+    return (FileT<ELFT>::canParse(magic) &&
+            elfHeader(buf)->e_machine == ContextT::machine);
   }
 
   std::error_code
@@ -57,12 +57,10 @@ protected:
 };
 
 template <typename ELFT, typename ContextT, template <typename> class FileT>
-using ELFObjectReader = ELFReader<ELFT, ContextT, FileT,
-                                  llvm::sys::fs::file_magic::elf_relocatable>;
+using ELFObjectReader = ELFReader<ELFT, ContextT, FileT>;
 
 template <typename ELFT, typename ContextT>
-using ELFDSOReader = ELFReader<ELFT, ContextT, DynamicFile,
-                               llvm::sys::fs::file_magic::elf_shared_object>;
+using ELFDSOReader = ELFReader<ELFT, ContextT, DynamicFile>;
 
 } // namespace elf
 } // namespace lld
-- 
2.7.4