Imported Upstream version 5.18.0.205

Former-commit-id: 7f59f7e792705db773f1caecdaa823092f4e2927

external/llvm/tools/dsymutil/NonRelocatableStringpool.h

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+//===- NonRelocatableStringpool.h - A simple stringpool  --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_DSYMUTIL_NONRELOCATABLESTRINGPOOL_H
+#define LLVM_TOOLS_DSYMUTIL_NONRELOCATABLESTRINGPOOL_H
+
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Allocator.h"
+#include <cstdint>
+#include <utility>
+
+namespace llvm {
+namespace dsymutil {
+
+/// \brief A string table that doesn't need relocations.
+///
+/// We are doing a final link, no need for a string table that
+/// has relocation entries for every reference to it. This class
+/// provides this ablitity by just associating offsets with
+/// strings.
+class NonRelocatableStringpool {
+public:
+  /// \brief 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<std::pair<uint32_t, StringMapEntryBase *>, BumpPtrAllocator>;
+
+  NonRelocatableStringpool() : Sentinel(0), Last(&Sentinel) {
+    // Legacy dsymutil puts an empty string at the start of the line
+    // table.
+    getStringOffset("");
+  }
+
+  /// \brief Get the offset of string \p S in the string table. This
+  /// can insert a new element or return the offset of a preexisitng
+  /// one.
+  uint32_t getStringOffset(StringRef S);
+
+  /// \brief Get permanent storage for \p S (but do not necessarily
+  /// emit \p S in the output section).
+  /// \returns The StringRef that points to permanent storage to use
+  /// in place of \p S.
+  StringRef internString(StringRef S);
+
+  // \brief Return the first entry of the string table.
+  const MapTy::MapEntryTy *getFirstEntry() const {
+    return getNextEntry(&Sentinel);
+  }
+
+  // \brief Get the entry following \p E in the string table or null
+  // if \p E was the last entry.
+  const MapTy::MapEntryTy *getNextEntry(const MapTy::MapEntryTy *E) const {
+    return static_cast<const MapTy::MapEntryTy *>(E->getValue().second);
+  }
+
+  uint64_t getSize() { return CurrentEndOffset; }
+
+private:
+  MapTy Strings;
+  uint32_t CurrentEndOffset = 0;
+  MapTy::MapEntryTy Sentinel, *Last;
+};
+
+} // end namespace dsymutil
+} // end namespace llvm
+
+#endif // LLVM_TOOLS_DSYMUTIL_NONRELOCATABLESTRINGPOOL_H