Enables llvm dyn_cast for Assemblers.

src/IceAssemblerX8632.h

 //===- subzero/src/assembler_ia32.h - Assembler for x86-32 ------*- C++ -*-===//
 //
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Modified by the Subzero authors.
 //
 //===----------------------------------------------------------------------===//
 //
@@ skipping 319 matching lines @@
   intptr_t unresolved_near_positions_[kMaxUnresolvedBranches];
 
   friend class AssemblerX8632;
 };
 
 class AssemblerX8632 : public Assembler {
   AssemblerX8632(const AssemblerX8632 &) = delete;
   AssemblerX8632 &operator=(const AssemblerX8632 &) = delete;
 
 public:
-  explicit AssemblerX8632(bool use_far_branches = false) : Assembler() {
+  explicit AssemblerX8632(bool use_far_branches = false)
+      : Assembler(Asm_X8632) {
     // This mode is only needed and implemented for MIPS and ARM.
     assert(!use_far_branches);
     (void)use_far_branches;
   }
   ~AssemblerX8632() override;
 
   static const bool kNearJump = true;
   static const bool kFarJump = false;
 
   void alignFunction() override;
@@ skipping 19 matching lines @@
   Label *GetOrCreateCfgNodeLabel(SizeT NodeNumber);
   void bindCfgNodeLabel(SizeT NodeNumber) override;
   Label *GetOrCreateLocalLabel(SizeT Number);
   void BindLocalLabel(SizeT Number);
 
   bool fixupIsPCRel(FixupKind Kind) const override {
     // Currently assuming this is the only PC-rel relocation type used.
     return Kind == llvm::ELF::R_386_PC32;
   }
 
+  static bool classof(const Assembler *Asm) {
+    return Asm->getKind() == Asm_X8632;
+  }
+
   // Operations to emit GPR instructions (and dispatch on operand type).
   typedef void (AssemblerX8632::*TypedEmitGPR)(Type, GPRRegister);
   typedef void (AssemblerX8632::*TypedEmitAddr)(Type, const Address &);
   struct GPREmitterOneOp {
     TypedEmitGPR Reg;
     TypedEmitAddr Addr;
   };
 
   typedef void (AssemblerX8632::*TypedEmitGPRGPR)(Type, GPRRegister,
                                                   GPRRegister);
@@ skipping 525 matching lines @@
 inline void AssemblerX8632::emitFixup(AssemblerFixup *fixup) {
   Buffer.emitFixup(fixup);
 }
 
 inline void AssemblerX8632::emitOperandSizeOverride() { emitUint8(0x66); }
 
 } // end of namespace X8632
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEASSEMBLERX8632_H