APSIntType.cpp revision 4708b3dde86b06f40927ae9cf30a2de83949a8f2 
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
12using namespace clang;
13using namespace ento;
14
15APSIntType::RangeTestResultKind
16APSIntType::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