Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/Object/WasmTraits.h b/linux-x64/clang/include/llvm/Object/WasmTraits.h
new file mode 100644
index 0000000..ebcd00b
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+++ b/linux-x64/clang/include/llvm/Object/WasmTraits.h
@@ -0,0 +1,63 @@
+//===- WasmTraits.h - DenseMap traits for the Wasm structures ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides llvm::DenseMapInfo traits for the Wasm structures.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_OBJECT_WASMTRAITS_H
+#define LLVM_OBJECT_WASMTRAITS_H
+
+#include "llvm/ADT/Hashing.h"
+#include "llvm/BinaryFormat/Wasm.h"
+
+namespace llvm {
+
+template <typename T> struct DenseMapInfo;
+
+// Traits for using WasmSignature in a DenseMap.
+template <> struct DenseMapInfo<wasm::WasmSignature> {
+  static wasm::WasmSignature getEmptyKey() {
+    return wasm::WasmSignature{{}, 1};
+  }
+  static wasm::WasmSignature getTombstoneKey() {
+    return wasm::WasmSignature{{}, 2};
+  }
+  static unsigned getHashValue(const wasm::WasmSignature &Sig) {
+    unsigned H = hash_value(Sig.ReturnType);
+    for (int32_t Param : Sig.ParamTypes)
+      H = hash_combine(H, Param);
+    return H;
+  }
+  static bool isEqual(const wasm::WasmSignature &LHS,
+                      const wasm::WasmSignature &RHS) {
+    return LHS == RHS;
+  }
+};
+
+// Traits for using WasmGlobalType in a DenseMap
+template <> struct DenseMapInfo<wasm::WasmGlobalType> {
+  static wasm::WasmGlobalType getEmptyKey() {
+    return wasm::WasmGlobalType{1, true};
+  }
+  static wasm::WasmGlobalType getTombstoneKey() {
+    return wasm::WasmGlobalType{2, true};
+  }
+  static unsigned getHashValue(const wasm::WasmGlobalType &GlobalType) {
+    return hash_combine(GlobalType.Type, GlobalType.Mutable);
+  }
+  static bool isEqual(const wasm::WasmGlobalType &LHS,
+                      const wasm::WasmGlobalType &RHS) {
+    return LHS == RHS;
+  }
+};
+
+} // end namespace llvm
+
+#endif // LLVM_OBJECT_WASMTRAITS_H