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1 //===--- APSIntType.cpp - Simple record of the type of APSInts ------------===//
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 #include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
11 
12 using namespace clang;
13 using namespace ento;
14 
15 APSIntType::RangeTestResultKind
testInRange(const llvm::APSInt & Value,bool AllowSignConversions) const16 APSIntType::testInRange(const llvm::APSInt &Value,
17                         bool AllowSignConversions) const {
18 
19   // Negative numbers cannot be losslessly converted to unsigned type.
20   if (IsUnsigned && !AllowSignConversions &&
21       Value.isSigned() && Value.isNegative())
22     return RTR_Below;
23 
24   unsigned MinBits;
25   if (AllowSignConversions) {
26     if (Value.isSigned() && !IsUnsigned)
27       MinBits = Value.getMinSignedBits();
28     else
29       MinBits = Value.getActiveBits();
30 
31   } else {
32     // Signed integers can be converted to signed integers of the same width
33     // or (if positive) unsigned integers with one fewer bit.
34     // Unsigned integers can be converted to unsigned integers of the same width
35     // or signed integers with one more bit.
36     if (Value.isSigned())
37       MinBits = Value.getMinSignedBits() - IsUnsigned;
38     else
39       MinBits = Value.getActiveBits() + !IsUnsigned;
40   }
41 
42   if (MinBits <= BitWidth)
43     return RTR_Within;
44 
45   if (Value.isSigned() && Value.isNegative())
46     return RTR_Below;
47   else
48     return RTR_Above;
49 }
50