1//===--- APNumericStorage.h - Store APInt/APFloat in ASTContext -*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_CLANG_AST_APNUMERICSTORAGE_H
10#define LLVM_CLANG_AST_APNUMERICSTORAGE_H
11
12#include "llvm/ADT/APFloat.h"
13#include "llvm/ADT/APInt.h"
14
15namespace clang {
16class ASTContext;
17
18/// Used by IntegerLiteral/FloatingLiteral/EnumConstantDecl to store the
19/// numeric without leaking memory.
20///
21/// For large floats/integers, APFloat/APInt will allocate memory from the heap
22/// to represent these numbers.  Unfortunately, when we use a BumpPtrAllocator
23/// to allocate IntegerLiteral/FloatingLiteral nodes the memory associated with
24/// the APFloat/APInt values will never get freed. APNumericStorage uses
25/// ASTContext's allocator for memory allocation.
26class APNumericStorage {
27  union {
28    uint64_t VAL;   ///< Used to store the <= 64 bits integer value.
29    uint64_t *pVal; ///< Used to store the >64 bits integer value.
30  };
31  unsigned BitWidth;
32
33  bool hasAllocation() const { return llvm::APInt::getNumWords(BitWidth) > 1; }
34
35  APNumericStorage(const APNumericStorage &) = delete;
36  void operator=(const APNumericStorage &) = delete;
37
38protected:
39  APNumericStorage() : VAL(0), BitWidth(0) {}
40
41  llvm::APInt getIntValue() const {
42    unsigned NumWords = llvm::APInt::getNumWords(BitWidth);
43    if (NumWords > 1)
44      return llvm::APInt(BitWidth, NumWords, pVal);
45    else
46      return llvm::APInt(BitWidth, VAL);
47  }
48  void setIntValue(const ASTContext &C, const llvm::APInt &Val);
49};
50
51class APIntStorage : private APNumericStorage {
52public:
53  llvm::APInt getValue() const { return getIntValue(); }
54  void setValue(const ASTContext &C, const llvm::APInt &Val) {
55    setIntValue(C, Val);
56  }
57};
58
59class APFloatStorage : private APNumericStorage {
60public:
61  llvm::APFloat getValue(const llvm::fltSemantics &Semantics) const {
62    return llvm::APFloat(Semantics, getIntValue());
63  }
64  void setValue(const ASTContext &C, const llvm::APFloat &Val) {
65    setIntValue(C, Val.bitcastToAPInt());
66  }
67};
68
69} // end namespace clang
70
71#endif // LLVM_CLANG_AST_APNUMERICSTORAGE_H
72