1 files changed, 58 insertions, 0 deletions
diff --git a/src/support/name.h b/src/support/name.h
new file mode 100644
index 000000000..9853f5462
--- /dev/null
+++ b/src/support/name.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2017 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef wasm_support_string_h
+#define wasm_support_string_h
+
+#include <cstring>
+
+#include "emscripten-optimizer/istring.h"
+
+namespace wasm {
+
+// We use a Name for all of the identifiers. These are IStrings, so they are
+// all interned - comparisons etc are just pointer comparisons, so there is no
+// perf loss. Having names everywhere makes using the AST much nicer (for
+// example, block names are strings and not offsets, which makes composition
+// - adding blocks, removing blocks - easy). One exception is local variables,
+// where we do use indices, as they are a large proportion of the AST,
+// perf matters a lot there, and compositionality is not a problem.
+// TODO: as an optimization, IString values < some threshold could be considered
+//       numerical indices directly.
+
+struct Name : public cashew::IString {
+  Name() : cashew::IString() {}
+  Name(const char* str) : cashew::IString(str, false) {}
+  Name(cashew::IString str) : cashew::IString(str) {}
+  Name(const std::string& str) : cashew::IString(str.c_str(), false) {}
+
+  friend std::ostream& operator<<(std::ostream& o, Name name) {
+    assert(name.str);
+    return o << '$' << name.str; // reference interpreter requires we prefix all names
+  }
+
+  static Name fromInt(size_t i) {
+    return cashew::IString(std::to_string(i).c_str(), false);
+  }
+
+  bool hasSubstring(cashew::IString substring) {
+    return strstr(c_str(), substring.c_str()) != nullptr;
+  }
+};
+
+} // namespace wasm
+
+#endif // wasm_support_string_h