Subzero: Use -filetype instead of -ias and -elf-writer.

src/IceDefs.h

 //===- subzero/src/IceDefs.h - Common Subzero declaraions -------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares various useful types and classes that have
@@ skipping 159 matching lines @@
   IceV_RegOrigins = 1 << 6,
   IceV_LinearScan = 1 << 7,
   IceV_Frame = 1 << 8,
   IceV_AddrOpt = 1 << 9,
   IceV_Random = 1 << 10,
   IceV_All = ~IceV_None,
   IceV_Most = IceV_All & ~IceV_LinearScan
 };
 typedef uint32_t VerboseMask;
 
+enum FileType {
+  FT_Elf, // ELF .o file
+  FT_Asm, // Assembly .s file
+  FT_Iasm // "Integrated assembler" .byte-style .s file
+};
+
 typedef llvm::raw_ostream Ostream;
 typedef llvm::raw_fd_ostream Fdstream;
 
 typedef std::mutex GlobalLockType;
 
 enum ErrorCodes { EC_None = 0, EC_Args, EC_Bitcode, EC_Translation };
 
 // Wrapper around std::error_code for allowing multiple errors to be
 // folded into one.  The current implementation keeps track of the
 // first error, which is likely to be the most useful one, and this
@@ skipping 23 matching lines @@
   return llvm::make_range(Container.rbegin(), Container.rend());
 }
 template <typename T>
 llvm::iterator_range<typename T::reverse_iterator> reverse_range(T &Container) {
   return llvm::make_range(Container.rbegin(), Container.rend());
 }
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEDEFS_H