1 //===-- llvm/ADT/APSInt.cpp - Arbitrary Precision Signed Int ---*- 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 // This file implements the APSInt class, which is a simple class that 10 // represents an arbitrary sized integer that knows its signedness. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/ADT/APSInt.h" 15 #include "llvm/ADT/FoldingSet.h" 16 #include "llvm/ADT/StringRef.h" 17 #include <cassert> 18 19 using namespace llvm; 20 21 APSInt::APSInt(StringRef Str) { 22 assert(!Str.empty() && "Invalid string length"); 23 24 // (Over-)estimate the required number of bits. 25 unsigned NumBits = ((Str.size() * 64) / 19) + 2; 26 APInt Tmp(NumBits, Str, /*radix=*/10); 27 if (Str[0] == '-') { 28 unsigned MinBits = Tmp.getSignificantBits(); 29 if (MinBits < NumBits) 30 Tmp = Tmp.trunc(std::max<unsigned>(1, MinBits)); 31 *this = APSInt(Tmp, /*isUnsigned=*/false); 32 return; 33 } 34 unsigned ActiveBits = Tmp.getActiveBits(); 35 if (ActiveBits < NumBits) 36 Tmp = Tmp.trunc(std::max<unsigned>(1, ActiveBits)); 37 *this = APSInt(Tmp, /*isUnsigned=*/true); 38 } 39 40 void APSInt::Profile(FoldingSetNodeID& ID) const { 41 ID.AddInteger((unsigned) (IsUnsigned ? 1 : 0)); 42 APInt::Profile(ID); 43 } 44