xref: /freebsd/contrib/llvm-project/clang/lib/AST/Interp/Integral.h (revision 96190b4fef3b4a0cc3ca0606b0c4e3e69a5e6717) 
1 //===--- Integral.h - Wrapper for numeric types for the VM ------*- 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 // Defines the VM types and helpers operating on types.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_AST_INTERP_INTEGRAL_H
14 #define LLVM_CLANG_AST_INTERP_INTEGRAL_H
15 
16 #include "clang/AST/ComparisonCategories.h"
17 #include "clang/AST/APValue.h"
18 #include "llvm/ADT/APSInt.h"
19 #include "llvm/Support/MathExtras.h"
20 #include "llvm/Support/raw_ostream.h"
21 #include <cstddef>
22 #include <cstdint>
23 
24 #include "Primitives.h"
25 
26 namespace clang {
27 namespace interp {
28 
29 using APInt = llvm::APInt;
30 using APSInt = llvm::APSInt;
31 
32 template <bool Signed> class IntegralAP;
33 
34 // Helper structure to select the representation.
35 template <unsigned Bits, bool Signed> struct Repr;
36 template <> struct Repr<8, false> { using Type = uint8_t; };
37 template <> struct Repr<16, false> { using Type = uint16_t; };
38 template <> struct Repr<32, false> { using Type = uint32_t; };
39 template <> struct Repr<64, false> { using Type = uint64_t; };
40 template <> struct Repr<8, true> { using Type = int8_t; };
41 template <> struct Repr<16, true> { using Type = int16_t; };
42 template <> struct Repr<32, true> { using Type = int32_t; };
43 template <> struct Repr<64, true> { using Type = int64_t; };
44 
45 /// Wrapper around numeric types.
46 ///
47 /// These wrappers are required to shared an interface between APSint and
48 /// builtin primitive numeral types, while optimising for storage and
49 /// allowing methods operating on primitive type to compile to fast code.
50 template <unsigned Bits, bool Signed> class Integral final {
51 private:
52   template <unsigned OtherBits, bool OtherSigned> friend class Integral;
53 
54   // The primitive representing the integral.
55   using ReprT = typename Repr<Bits, Signed>::Type;
56   ReprT V;
57 
58   /// Primitive representing limits.
59   static const auto Min = std::numeric_limits<ReprT>::min();
60   static const auto Max = std::numeric_limits<ReprT>::max();
61 
62   /// Construct an integral from anything that is convertible to storage.
63   template <typename T> explicit Integral(T V) : V(V) {}
64 
65 public:
66   using AsUnsigned = Integral<Bits, false>;
67 
68   /// Zero-initializes an integral.
69   Integral() : V(0) {}
70 
71   /// Constructs an integral from another integral.
72   template <unsigned SrcBits, bool SrcSign>
73   explicit Integral(Integral<SrcBits, SrcSign> V) : V(V.V) {}
74 
75   /// Construct an integral from a value based on signedness.
76   explicit Integral(const APSInt &V)
77       : V(V.isSigned() ? V.getSExtValue() : V.getZExtValue()) {}
78 
79   bool operator<(Integral RHS) const { return V < RHS.V; }
80   bool operator>(Integral RHS) const { return V > RHS.V; }
81   bool operator<=(Integral RHS) const { return V <= RHS.V; }
82   bool operator>=(Integral RHS) const { return V >= RHS.V; }
83   bool operator==(Integral RHS) const { return V == RHS.V; }
84   bool operator!=(Integral RHS) const { return V != RHS.V; }
85 
86   bool operator>(unsigned RHS) const {
87     return V >= 0 && static_cast<unsigned>(V) > RHS;
88   }
89 
90   Integral operator-() const { return Integral(-V); }
91   Integral operator-(const Integral &Other) const {
92     return Integral(V - Other.V);
93   }
94   Integral operator~() const { return Integral(~V); }
95 
96   template <unsigned DstBits, bool DstSign>
97   explicit operator Integral<DstBits, DstSign>() const {
98     return Integral<DstBits, DstSign>(V);
99   }
100 
101   explicit operator unsigned() const { return V; }
102   explicit operator int64_t() const { return V; }
103   explicit operator uint64_t() const { return V; }
104   explicit operator int32_t() const { return V; }
105 
106   APSInt toAPSInt() const {
107     return APSInt(APInt(Bits, static_cast<uint64_t>(V), Signed), !Signed);
108   }
109   APSInt toAPSInt(unsigned NumBits) const {
110     if constexpr (Signed)
111       return APSInt(toAPSInt().sextOrTrunc(NumBits), !Signed);
112     else
113       return APSInt(toAPSInt().zextOrTrunc(NumBits), !Signed);
114   }
115   APValue toAPValue() const { return APValue(toAPSInt()); }
116 
117   Integral<Bits, false> toUnsigned() const {
118     return Integral<Bits, false>(*this);
119   }
120 
121   constexpr static unsigned bitWidth() { return Bits; }
122 
123   bool isZero() const { return !V; }
124 
125   bool isMin() const { return *this == min(bitWidth()); }
126 
127   bool isMinusOne() const { return Signed && V == ReprT(-1); }
128 
129   constexpr static bool isSigned() { return Signed; }
130 
131   bool isNegative() const { return V < ReprT(0); }
132   bool isPositive() const { return !isNegative(); }
133 
134   ComparisonCategoryResult compare(const Integral &RHS) const {
135     return Compare(V, RHS.V);
136   }
137 
138   std::string toDiagnosticString(const ASTContext &Ctx) const {
139     std::string NameStr;
140     llvm::raw_string_ostream OS(NameStr);
141     OS << V;
142     return NameStr;
143   }
144 
145   unsigned countLeadingZeros() const {
146     if constexpr (!Signed)
147       return llvm::countl_zero<ReprT>(V);
148     llvm_unreachable("Don't call countLeadingZeros() on signed types.");
149   }
150 
151   Integral truncate(unsigned TruncBits) const {
152     if (TruncBits >= Bits)
153       return *this;
154     const ReprT BitMask = (ReprT(1) << ReprT(TruncBits)) - 1;
155     const ReprT SignBit = ReprT(1) << (TruncBits - 1);
156     const ReprT ExtMask = ~BitMask;
157     return Integral((V & BitMask) | (Signed && (V & SignBit) ? ExtMask : 0));
158   }
159 
160   void print(llvm::raw_ostream &OS) const { OS << V; }
161 
162   static Integral min(unsigned NumBits) {
163     return Integral(Min);
164   }
165   static Integral max(unsigned NumBits) {
166     return Integral(Max);
167   }
168 
169   template <typename ValT> static Integral from(ValT Value) {
170     if constexpr (std::is_integral<ValT>::value)
171       return Integral(Value);
172     else
173       return Integral::from(static_cast<Integral::ReprT>(Value));
174   }
175 
176   template <unsigned SrcBits, bool SrcSign>
177   static std::enable_if_t<SrcBits != 0, Integral>
178   from(Integral<SrcBits, SrcSign> Value) {
179     return Integral(Value.V);
180   }
181 
182   static Integral zero() { return from(0); }
183 
184   template <typename T> static Integral from(T Value, unsigned NumBits) {
185     return Integral(Value);
186   }
187 
188   static bool inRange(int64_t Value, unsigned NumBits) {
189     return CheckRange<ReprT, Min, Max>(Value);
190   }
191 
192   static bool increment(Integral A, Integral *R) {
193     return add(A, Integral(ReprT(1)), A.bitWidth(), R);
194   }
195 
196   static bool decrement(Integral A, Integral *R) {
197     return sub(A, Integral(ReprT(1)), A.bitWidth(), R);
198   }
199 
200   static bool add(Integral A, Integral B, unsigned OpBits, Integral *R) {
201     return CheckAddUB(A.V, B.V, R->V);
202   }
203 
204   static bool sub(Integral A, Integral B, unsigned OpBits, Integral *R) {
205     return CheckSubUB(A.V, B.V, R->V);
206   }
207 
208   static bool mul(Integral A, Integral B, unsigned OpBits, Integral *R) {
209     return CheckMulUB(A.V, B.V, R->V);
210   }
211 
212   static bool rem(Integral A, Integral B, unsigned OpBits, Integral *R) {
213     *R = Integral(A.V % B.V);
214     return false;
215   }
216 
217   static bool div(Integral A, Integral B, unsigned OpBits, Integral *R) {
218     *R = Integral(A.V / B.V);
219     return false;
220   }
221 
222   static bool bitAnd(Integral A, Integral B, unsigned OpBits, Integral *R) {
223     *R = Integral(A.V & B.V);
224     return false;
225   }
226 
227   static bool bitOr(Integral A, Integral B, unsigned OpBits, Integral *R) {
228     *R = Integral(A.V | B.V);
229     return false;
230   }
231 
232   static bool bitXor(Integral A, Integral B, unsigned OpBits, Integral *R) {
233     *R = Integral(A.V ^ B.V);
234     return false;
235   }
236 
237   static bool neg(Integral A, Integral *R) {
238     if (Signed && A.isMin())
239       return true;
240 
241     *R = -A;
242     return false;
243   }
244 
245   static bool comp(Integral A, Integral *R) {
246     *R = Integral(~A.V);
247     return false;
248   }
249 
250   template <unsigned RHSBits, bool RHSSign>
251   static void shiftLeft(const Integral A, const Integral<RHSBits, RHSSign> B,
252                         unsigned OpBits, Integral *R) {
253     *R = Integral::from(A.V << B.V, OpBits);
254   }
255 
256   template <unsigned RHSBits, bool RHSSign>
257   static void shiftRight(const Integral A, const Integral<RHSBits, RHSSign> B,
258                          unsigned OpBits, Integral *R) {
259     *R = Integral::from(A.V >> B.V, OpBits);
260   }
261 
262 private:
263   template <typename T> static bool CheckAddUB(T A, T B, T &R) {
264     if constexpr (std::is_signed_v<T>) {
265       return llvm::AddOverflow<T>(A, B, R);
266     } else {
267       R = A + B;
268       return false;
269     }
270   }
271 
272   template <typename T> static bool CheckSubUB(T A, T B, T &R) {
273     if constexpr (std::is_signed_v<T>) {
274       return llvm::SubOverflow<T>(A, B, R);
275     } else {
276       R = A - B;
277       return false;
278     }
279   }
280 
281   template <typename T> static bool CheckMulUB(T A, T B, T &R) {
282     if constexpr (std::is_signed_v<T>) {
283       return llvm::MulOverflow<T>(A, B, R);
284     } else {
285       R = A * B;
286       return false;
287     }
288   }
289   template <typename T, T Min, T Max> static bool CheckRange(int64_t V) {
290     if constexpr (std::is_signed_v<T>) {
291       return Min <= V && V <= Max;
292     } else {
293       return V >= 0 && static_cast<uint64_t>(V) <= Max;
294     }
295   }
296 };
297 
298 template <unsigned Bits, bool Signed>
299 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, Integral<Bits, Signed> I) {
300   I.print(OS);
301   return OS;
302 }
303 
304 } // namespace interp
305 } // namespace clang
306 
307 #endif
308