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thirdparty/capstone/suite/synctools/tablegen/include/llvm/CodeGen/NonRelocatableStringpool.h

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+//===- NonRelocatableStringpool.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_CODEGEN_NONRELOCATABLESTRINGPOOL_H
+#define LLVM_CODEGEN_NONRELOCATABLESTRINGPOOL_H
+
+#include "llvm/CodeGen/DwarfStringPoolEntry.h"
+#include "llvm/Support/Allocator.h"
+#include <cstdint>
+#include <vector>
+
+namespace llvm {
+
+/// A string table that doesn't need relocations.
+///
+/// Use this class when a string table doesn't need relocations.
+/// This class provides this ability by just associating offsets with strings.
+class NonRelocatableStringpool {
+public:
+  /// Entries are stored into the StringMap and simply linked together through
+  /// the second element of this pair in order to keep track of insertion
+  /// order.
+  using MapTy = StringMap<DwarfStringPoolEntry, BumpPtrAllocator>;
+
+  NonRelocatableStringpool(
+      std::function<StringRef(StringRef Input)> Translator = nullptr,
+      bool PutEmptyString = false)
+      : Translator(Translator) {
+    if (PutEmptyString)
+      EmptyString = getEntry("");
+  }
+
+  DwarfStringPoolEntryRef getEntry(StringRef S);
+
+  /// Get the offset of string \p S in the string table. This can insert a new
+  /// element or return the offset of a pre-existing one.
+  uint64_t getStringOffset(StringRef S) { return getEntry(S).getOffset(); }
+
+  /// Get permanent storage for \p S (but do not necessarily emit \p S in the
+  /// output section). A latter call to getStringOffset() with the same string
+  /// will chain it though.
+  ///
+  /// \returns The StringRef that points to permanent storage to use
+  /// in place of \p S.
+  StringRef internString(StringRef S);
+
+  uint64_t getSize() { return CurrentEndOffset; }
+
+  /// Return the list of strings to be emitted. This does not contain the
+  /// strings which were added via internString only.
+  std::vector<DwarfStringPoolEntryRef> getEntriesForEmission() const;
+
+private:
+  MapTy Strings;
+  uint64_t CurrentEndOffset = 0;
+  unsigned NumEntries = 0;
+  DwarfStringPoolEntryRef EmptyString;
+  std::function<StringRef(StringRef Input)> Translator;
+};
+
+/// Helper for making strong types.
+template <typename T, typename S> class StrongType : public T {
+public:
+  template <typename... Args>
+  explicit StrongType(Args... A) : T(std::forward<Args>(A)...) {}
+};
+
+/// It's very easy to introduce bugs by passing the wrong string pool.
+/// By using strong types the interface enforces that the right
+/// kind of pool is used.
+struct UniqueTag {};
+struct OffsetsTag {};
+using UniquingStringPool = StrongType<NonRelocatableStringpool, UniqueTag>;
+using OffsetsStringPool = StrongType<NonRelocatableStringpool, OffsetsTag>;
+
+} // end namespace llvm
+
+#endif // LLVM_CODEGEN_NONRELOCATABLESTRINGPOOL_H