Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/MC/MCDisassembler/MCExternalSymbolizer.h b/linux-x64/clang/include/llvm/MC/MCDisassembler/MCExternalSymbolizer.h
new file mode 100644
index 0000000..bd3e5d4
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+++ b/linux-x64/clang/include/llvm/MC/MCDisassembler/MCExternalSymbolizer.h
@@ -0,0 +1,58 @@
+//===-- llvm/MC/MCExternalSymbolizer.h - ------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the declaration of the MCExternalSymbolizer class, which
+// enables library users to provide callbacks (through the C API) to do the
+// symbolization externally.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_MCDISASSEMBLER_MCEXTERNALSYMBOLIZER_H
+#define LLVM_MC_MCDISASSEMBLER_MCEXTERNALSYMBOLIZER_H
+
+#include "llvm-c/Disassembler.h"
+#include "llvm/MC/MCDisassembler/MCSymbolizer.h"
+#include <memory>
+
+namespace llvm {
+
+/// \brief Symbolize using user-provided, C API, callbacks.
+///
+/// See llvm-c/Disassembler.h.
+class MCExternalSymbolizer : public MCSymbolizer {
+protected:
+  /// \name Hooks for symbolic disassembly via the public 'C' interface.
+  /// @{
+  /// The function to get the symbolic information for operands.
+  LLVMOpInfoCallback GetOpInfo;
+  /// The function to lookup a symbol name.
+  LLVMSymbolLookupCallback SymbolLookUp;
+  /// The pointer to the block of symbolic information for above call back.
+  void *DisInfo;
+  /// @}
+
+public:
+  MCExternalSymbolizer(MCContext &Ctx,
+                       std::unique_ptr<MCRelocationInfo> RelInfo,
+                       LLVMOpInfoCallback getOpInfo,
+                       LLVMSymbolLookupCallback symbolLookUp, void *disInfo)
+    : MCSymbolizer(Ctx, std::move(RelInfo)), GetOpInfo(getOpInfo),
+      SymbolLookUp(symbolLookUp), DisInfo(disInfo) {}
+
+  bool tryAddingSymbolicOperand(MCInst &MI, raw_ostream &CommentStream,
+                                int64_t Value, uint64_t Address, bool IsBranch,
+                                uint64_t Offset, uint64_t InstSize) override;
+  void tryAddingPcLoadReferenceComment(raw_ostream &CommentStream,
+                                       int64_t Value,
+                                       uint64_t Address) override;
+};
+
+}
+
+#endif