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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)
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;
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
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