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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.
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/DwarfStringPoolEntry.h"
#include "llvm/Support/Allocator.h"
#include <cstdint>
#include <vector>
namespace llvm {
namespace dsymutil {
/// 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 ability by just
/// associating offsets with strings.
class NonRelocatableStringpool {
/// 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() {
// Legacy dsymutil puts an empty string at the start of the line table.
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.
uint32_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; }
std::vector<DwarfStringPoolEntryRef> getEntries() const;
MapTy Strings;
uint32_t CurrentEndOffset = 0;
unsigned NumEntries = 0;
DwarfStringPoolEntryRef EmptyString;
/// Helper for making strong types.
template <typename T, typename S> class StrongType : public T {
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 in the
/// dwarf linker. 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 dsymutil
} // end namespace llvm