[WebAssembly] Add DenseMap traits and operator== for Wasm type structs. NFC

[ncw]

Summary

These were previously defined inline in LLD

---

(see D44150 for previous discussion)

[ncw]

D44150 is blocked on this. There's not a huge benefit to moving the header into the LLVM repo, but it could enable code-sharing with WasmObjectWriter which would be nice.

include/llvm/BinaryFormat/Wasm.h

 #define WASM_RELOC(name, value) name = value,
 
 enum : unsigned {
 #include "WasmRelocs.def"
 };
 
 #undef WASM_RELOC
 
+// Useful comparison operators
+inline bool operator==(const WasmSignature &LHS, const WasmSignature &RHS) {
+  return LHS.ReturnType == RHS.ReturnType && LHS.ParamTypes == RHS.ParamTypes;
+}
+
+inline bool operator!=(const WasmSignature &LHS, const WasmSignature &RHS) {
+  return !(LHS == RHS);
+}
+
+inline bool operator==(const WasmGlobalType &LHS, const WasmGlobalType &RHS) {
+  return LHS.Type == RHS.Type && LHS.Mutable == RHS.Mutable;
+}
+
+inline bool operator!=(const WasmGlobalType &LHS, const WasmGlobalType &RHS) {
+  return !(LHS == RHS);
+}
+
 } // end namespace wasm
 } // end namespace llvm
 
 #endif

include/llvm/Object/WasmTraits.h

+//===- 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