Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 57 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Support/StringSaver.h b/clang-r353983/include/llvm/Support/StringSaver.h
new file mode 100644
index 00000000..c54044e3
--- /dev/null
+++ b/clang-r353983/include/llvm/Support/StringSaver.h
@@ -0,0 +1,57 @@
+//===- llvm/Support/StringSaver.h -------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_STRINGSAVER_H
+#define LLVM_SUPPORT_STRINGSAVER_H
+
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Support/Allocator.h"
+
+namespace llvm {
+
+/// Saves strings in the provided stable storage and returns a
+/// StringRef with a stable character pointer.
+class StringSaver final {
+  BumpPtrAllocator &Alloc;
+
+public:
+  StringSaver(BumpPtrAllocator &Alloc) : Alloc(Alloc) {}
+
+  // All returned strings are null-terminated: *save(S).end() == 0.
+  StringRef save(const char *S) { return save(StringRef(S)); }
+  StringRef save(StringRef S);
+  StringRef save(const Twine &S) { return save(StringRef(S.str())); }
+  StringRef save(const std::string &S) { return save(StringRef(S)); }
+};
+
+/// Saves strings in the provided stable storage and returns a StringRef with a
+/// stable character pointer. Saving the same string yields the same StringRef.
+///
+/// Compared to StringSaver, it does more work but avoids saving the same string
+/// multiple times.
+///
+/// Compared to StringPool, it performs fewer allocations but doesn't support
+/// refcounting/deletion.
+class UniqueStringSaver final {
+  StringSaver Strings;
+  llvm::DenseSet<llvm::StringRef> Unique;
+
+public:
+  UniqueStringSaver(BumpPtrAllocator &Alloc) : Strings(Alloc) {}
+
+  // All returned strings are null-terminated: *save(S).end() == 0.
+  StringRef save(const char *S) { return save(StringRef(S)); }
+  StringRef save(StringRef S);
+  StringRef save(const Twine &S) { return save(StringRef(S.str())); }
+  StringRef save(const std::string &S) { return save(StringRef(S)); }
+};
+
+}
+#endif