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3637aff1ea
Summary: When constructing an APSInt from a string, the constructor doesn't correctly truncate the bit width of the result if the passed in string was "0" (or any alternative way to express 0 like "-0" or "000"). Instead of 1 (which is the smallest allowed bit width) it returns an APSInt with a bit width of 5. The reason is that the constructor checks that it never truncates the result to the invalid bit width of 0, so when it calculates that storing a "0" doesn't require any bits it just keeps the original overestimated bit width (which happens to be 5). This patch just sets the bit width of the result to 1 if the required bit width is 0. Reviewers: arphaman, dexonsmith Reviewed By: dexonsmith Subscribers: hiraditya, dexonsmith, JDevlieghere, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D81329
44 lines
1.4 KiB
C++
44 lines
1.4 KiB
C++
//===-- llvm/ADT/APSInt.cpp - Arbitrary Precision Signed Int ---*- C++ -*--===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the APSInt class, which is a simple class that
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// represents an arbitrary sized integer that knows its signedness.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/APSInt.h"
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#include "llvm/ADT/FoldingSet.h"
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#include "llvm/ADT/StringRef.h"
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#include <cassert>
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using namespace llvm;
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APSInt::APSInt(StringRef Str) {
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assert(!Str.empty() && "Invalid string length");
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// (Over-)estimate the required number of bits.
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unsigned NumBits = ((Str.size() * 64) / 19) + 2;
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APInt Tmp(NumBits, Str, /*radix=*/10);
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if (Str[0] == '-') {
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unsigned MinBits = Tmp.getMinSignedBits();
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if (MinBits < NumBits)
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Tmp = Tmp.trunc(std::max<unsigned>(1, MinBits));
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*this = APSInt(Tmp, /*isUnsigned=*/false);
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return;
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}
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unsigned ActiveBits = Tmp.getActiveBits();
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if (ActiveBits < NumBits)
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Tmp = Tmp.trunc(std::max<unsigned>(1, ActiveBits));
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*this = APSInt(Tmp, /*isUnsigned=*/true);
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}
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void APSInt::Profile(FoldingSetNodeID& ID) const {
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ID.AddInteger((unsigned) (IsUnsigned ? 1 : 0));
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APInt::Profile(ID);
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}
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