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APSIntType.h
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1 //== APSIntType.h - Simple record of the type of APSInts --------*- C++ -*--==//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_APSINTTYPE_H
11 #define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_APSINTTYPE_H
12 
13 #include "llvm/ADT/APSInt.h"
14 #include <tuple>
15 
16 namespace clang {
17 namespace ento {
18 
19 /// \brief A record of the "type" of an APSInt, used for conversions.
20 class APSIntType {
21  uint32_t BitWidth;
22  bool IsUnsigned;
23 
24 public:
25  APSIntType(uint32_t Width, bool Unsigned)
26  : BitWidth(Width), IsUnsigned(Unsigned) {}
27 
28  /* implicit */ APSIntType(const llvm::APSInt &Value)
29  : BitWidth(Value.getBitWidth()), IsUnsigned(Value.isUnsigned()) {}
30 
31  uint32_t getBitWidth() const { return BitWidth; }
32  bool isUnsigned() const { return IsUnsigned; }
33 
34  /// \brief Convert a given APSInt, in place, to match this type.
35  ///
36  /// This behaves like a C cast: converting 255u8 (0xFF) to s16 gives
37  /// 255 (0x00FF), and converting -1s8 (0xFF) to u16 gives 65535 (0xFFFF).
38  void apply(llvm::APSInt &Value) const {
39  // Note the order here. We extend first to preserve the sign, if this value
40  // is signed, /then/ match the signedness of the result type.
41  Value = Value.extOrTrunc(BitWidth);
42  Value.setIsUnsigned(IsUnsigned);
43  }
44 
45  /// Convert and return a new APSInt with the given value, but this
46  /// type's bit width and signedness.
47  ///
48  /// \see apply
49  llvm::APSInt convert(const llvm::APSInt &Value) const LLVM_READONLY {
50  llvm::APSInt Result(Value, Value.isUnsigned());
51  apply(Result);
52  return Result;
53  }
54 
55  /// Returns an all-zero value for this type.
56  llvm::APSInt getZeroValue() const LLVM_READONLY {
57  return llvm::APSInt(BitWidth, IsUnsigned);
58  }
59 
60  /// Returns the minimum value for this type.
61  llvm::APSInt getMinValue() const LLVM_READONLY {
62  return llvm::APSInt::getMinValue(BitWidth, IsUnsigned);
63  }
64 
65  /// Returns the maximum value for this type.
66  llvm::APSInt getMaxValue() const LLVM_READONLY {
67  return llvm::APSInt::getMaxValue(BitWidth, IsUnsigned);
68  }
69 
70  llvm::APSInt getValue(uint64_t RawValue) const LLVM_READONLY {
71  return (llvm::APSInt(BitWidth, IsUnsigned) = RawValue);
72  }
73 
74  /// Used to classify whether a value is representable using this type.
75  ///
76  /// \see testInRange
78  RTR_Below = -1, ///< Value is less than the minimum representable value.
79  RTR_Within = 0, ///< Value is representable using this type.
80  RTR_Above = 1 ///< Value is greater than the maximum representable value.
81  };
82 
83  /// Tests whether a given value is losslessly representable using this type.
84  ///
85  /// \param Val The value to test.
86  /// \param AllowMixedSign Whether or not to allow signedness conversions.
87  /// This determines whether -1s8 is considered in range
88  /// for 'unsigned char' (u8).
89  RangeTestResultKind testInRange(const llvm::APSInt &Val,
90  bool AllowMixedSign) const LLVM_READONLY;
91 
92  bool operator==(const APSIntType &Other) const {
93  return BitWidth == Other.BitWidth && IsUnsigned == Other.IsUnsigned;
94  }
95 
96  /// \brief Provide an ordering for finding a common conversion type.
97  ///
98  /// Unsigned integers are considered to be better conversion types than
99  /// signed integers of the same width.
100  bool operator<(const APSIntType &Other) const {
101  return std::tie(BitWidth, IsUnsigned) <
102  std::tie(Other.BitWidth, Other.IsUnsigned);
103  }
104 };
105 
106 } // end ento namespace
107 } // end clang namespace
108 
109 #endif
bool operator==(const APSIntType &Other) const
Definition: APSIntType.h:92
Value is less than the minimum representable value.
Definition: APSIntType.h:78
APSIntType(const llvm::APSInt &Value)
Definition: APSIntType.h:28
Value is representable using this type.
Definition: APSIntType.h:79
A record of the "type" of an APSInt, used for conversions.
Definition: APSIntType.h:20
APSIntType(uint32_t Width, bool Unsigned)
Definition: APSIntType.h:25
RangeTestResultKind testInRange(const llvm::APSInt &Val, bool AllowMixedSign) const LLVM_READONLY
Tests whether a given value is losslessly representable using this type.
Definition: APSIntType.cpp:16
llvm::APSInt getZeroValue() const LLVM_READONLY
Returns an all-zero value for this type.
Definition: APSIntType.h:56
llvm::APSInt getMinValue() const LLVM_READONLY
Returns the minimum value for this type.
Definition: APSIntType.h:61
uint32_t getBitWidth() const
Definition: APSIntType.h:31
llvm::APSInt getMaxValue() const LLVM_READONLY
Returns the maximum value for this type.
Definition: APSIntType.h:66
bool operator<(const APSIntType &Other) const
Provide an ordering for finding a common conversion type.
Definition: APSIntType.h:100
Value is greater than the maximum representable value.
Definition: APSIntType.h:80
RangeTestResultKind
Used to classify whether a value is representable using this type.
Definition: APSIntType.h:77
llvm::APSInt getValue(uint64_t RawValue) const LLVM_READONLY
Definition: APSIntType.h:70
llvm::APSInt convert(const llvm::APSInt &Value) const LLVM_READONLY
Convert and return a new APSInt with the given value, but this type&#39;s bit width and signedness...
Definition: APSIntType.h:49
Dataflow Directional Tag Classes.
bool isUnsigned() const
Definition: APSIntType.h:32
void apply(llvm::APSInt &Value) const
Convert a given APSInt, in place, to match this type.
Definition: APSIntType.h:38