llvm-6502/include/llvm/ADT/BitVector.h
Jakob Stoklund Olesen 0057022489 Remove the expensive BitVector::operator~().
Returning a temporary BitVector is very expensive. If you must, create
the temporary explicitly: Use BitVector(A).flip() instead of ~A.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156768 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-14 15:46:27 +00:00

491 lines
14 KiB
C++

//===- llvm/ADT/BitVector.h - Bit vectors -----------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the BitVector class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_BITVECTOR_H
#define LLVM_ADT_BITVECTOR_H
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include <algorithm>
#include <cassert>
#include <climits>
#include <cstdlib>
namespace llvm {
class BitVector {
typedef unsigned long BitWord;
enum { BITWORD_SIZE = (unsigned)sizeof(BitWord) * CHAR_BIT };
BitWord *Bits; // Actual bits.
unsigned Size; // Size of bitvector in bits.
unsigned Capacity; // Size of allocated memory in BitWord.
public:
// Encapsulation of a single bit.
class reference {
friend class BitVector;
BitWord *WordRef;
unsigned BitPos;
reference(); // Undefined
public:
reference(BitVector &b, unsigned Idx) {
WordRef = &b.Bits[Idx / BITWORD_SIZE];
BitPos = Idx % BITWORD_SIZE;
}
~reference() {}
reference &operator=(reference t) {
*this = bool(t);
return *this;
}
reference& operator=(bool t) {
if (t)
*WordRef |= 1L << BitPos;
else
*WordRef &= ~(1L << BitPos);
return *this;
}
operator bool() const {
return ((*WordRef) & (1L << BitPos)) ? true : false;
}
};
/// BitVector default ctor - Creates an empty bitvector.
BitVector() : Size(0), Capacity(0) {
Bits = 0;
}
/// BitVector ctor - Creates a bitvector of specified number of bits. All
/// bits are initialized to the specified value.
explicit BitVector(unsigned s, bool t = false) : Size(s) {
Capacity = NumBitWords(s);
Bits = (BitWord *)std::malloc(Capacity * sizeof(BitWord));
init_words(Bits, Capacity, t);
if (t)
clear_unused_bits();
}
/// BitVector copy ctor.
BitVector(const BitVector &RHS) : Size(RHS.size()) {
if (Size == 0) {
Bits = 0;
Capacity = 0;
return;
}
Capacity = NumBitWords(RHS.size());
Bits = (BitWord *)std::malloc(Capacity * sizeof(BitWord));
std::memcpy(Bits, RHS.Bits, Capacity * sizeof(BitWord));
}
~BitVector() {
std::free(Bits);
}
/// empty - Tests whether there are no bits in this bitvector.
bool empty() const { return Size == 0; }
/// size - Returns the number of bits in this bitvector.
unsigned size() const { return Size; }
/// count - Returns the number of bits which are set.
unsigned count() const {
unsigned NumBits = 0;
for (unsigned i = 0; i < NumBitWords(size()); ++i)
if (sizeof(BitWord) == 4)
NumBits += CountPopulation_32((uint32_t)Bits[i]);
else if (sizeof(BitWord) == 8)
NumBits += CountPopulation_64(Bits[i]);
else
llvm_unreachable("Unsupported!");
return NumBits;
}
/// any - Returns true if any bit is set.
bool any() const {
for (unsigned i = 0; i < NumBitWords(size()); ++i)
if (Bits[i] != 0)
return true;
return false;
}
/// all - Returns true if all bits are set.
bool all() const {
// TODO: Optimize this.
return count() == size();
}
/// none - Returns true if none of the bits are set.
bool none() const {
return !any();
}
/// find_first - Returns the index of the first set bit, -1 if none
/// of the bits are set.
int find_first() const {
for (unsigned i = 0; i < NumBitWords(size()); ++i)
if (Bits[i] != 0) {
if (sizeof(BitWord) == 4)
return i * BITWORD_SIZE + CountTrailingZeros_32((uint32_t)Bits[i]);
if (sizeof(BitWord) == 8)
return i * BITWORD_SIZE + CountTrailingZeros_64(Bits[i]);
llvm_unreachable("Unsupported!");
}
return -1;
}
/// find_next - Returns the index of the next set bit following the
/// "Prev" bit. Returns -1 if the next set bit is not found.
int find_next(unsigned Prev) const {
++Prev;
if (Prev >= Size)
return -1;
unsigned WordPos = Prev / BITWORD_SIZE;
unsigned BitPos = Prev % BITWORD_SIZE;
BitWord Copy = Bits[WordPos];
// Mask off previous bits.
Copy &= ~0L << BitPos;
if (Copy != 0) {
if (sizeof(BitWord) == 4)
return WordPos * BITWORD_SIZE + CountTrailingZeros_32((uint32_t)Copy);
if (sizeof(BitWord) == 8)
return WordPos * BITWORD_SIZE + CountTrailingZeros_64(Copy);
llvm_unreachable("Unsupported!");
}
// Check subsequent words.
for (unsigned i = WordPos+1; i < NumBitWords(size()); ++i)
if (Bits[i] != 0) {
if (sizeof(BitWord) == 4)
return i * BITWORD_SIZE + CountTrailingZeros_32((uint32_t)Bits[i]);
if (sizeof(BitWord) == 8)
return i * BITWORD_SIZE + CountTrailingZeros_64(Bits[i]);
llvm_unreachable("Unsupported!");
}
return -1;
}
/// clear - Clear all bits.
void clear() {
Size = 0;
}
/// resize - Grow or shrink the bitvector.
void resize(unsigned N, bool t = false) {
if (N > Capacity * BITWORD_SIZE) {
unsigned OldCapacity = Capacity;
grow(N);
init_words(&Bits[OldCapacity], (Capacity-OldCapacity), t);
}
// Set any old unused bits that are now included in the BitVector. This
// may set bits that are not included in the new vector, but we will clear
// them back out below.
if (N > Size)
set_unused_bits(t);
// Update the size, and clear out any bits that are now unused
unsigned OldSize = Size;
Size = N;
if (t || N < OldSize)
clear_unused_bits();
}
void reserve(unsigned N) {
if (N > Capacity * BITWORD_SIZE)
grow(N);
}
// Set, reset, flip
BitVector &set() {
init_words(Bits, Capacity, true);
clear_unused_bits();
return *this;
}
BitVector &set(unsigned Idx) {
Bits[Idx / BITWORD_SIZE] |= 1L << (Idx % BITWORD_SIZE);
return *this;
}
BitVector &reset() {
init_words(Bits, Capacity, false);
return *this;
}
BitVector &reset(unsigned Idx) {
Bits[Idx / BITWORD_SIZE] &= ~(1L << (Idx % BITWORD_SIZE));
return *this;
}
BitVector &flip() {
for (unsigned i = 0; i < NumBitWords(size()); ++i)
Bits[i] = ~Bits[i];
clear_unused_bits();
return *this;
}
BitVector &flip(unsigned Idx) {
Bits[Idx / BITWORD_SIZE] ^= 1L << (Idx % BITWORD_SIZE);
return *this;
}
// Indexing.
reference operator[](unsigned Idx) {
assert (Idx < Size && "Out-of-bounds Bit access.");
return reference(*this, Idx);
}
bool operator[](unsigned Idx) const {
assert (Idx < Size && "Out-of-bounds Bit access.");
BitWord Mask = 1L << (Idx % BITWORD_SIZE);
return (Bits[Idx / BITWORD_SIZE] & Mask) != 0;
}
bool test(unsigned Idx) const {
return (*this)[Idx];
}
/// Test if any common bits are set.
bool anyCommon(const BitVector &RHS) const {
unsigned ThisWords = NumBitWords(size());
unsigned RHSWords = NumBitWords(RHS.size());
for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i)
if (Bits[i] & RHS.Bits[i])
return true;
return false;
}
// Comparison operators.
bool operator==(const BitVector &RHS) const {
unsigned ThisWords = NumBitWords(size());
unsigned RHSWords = NumBitWords(RHS.size());
unsigned i;
for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
if (Bits[i] != RHS.Bits[i])
return false;
// Verify that any extra words are all zeros.
if (i != ThisWords) {
for (; i != ThisWords; ++i)
if (Bits[i])
return false;
} else if (i != RHSWords) {
for (; i != RHSWords; ++i)
if (RHS.Bits[i])
return false;
}
return true;
}
bool operator!=(const BitVector &RHS) const {
return !(*this == RHS);
}
// Intersection, union, disjoint union.
BitVector &operator&=(const BitVector &RHS) {
unsigned ThisWords = NumBitWords(size());
unsigned RHSWords = NumBitWords(RHS.size());
unsigned i;
for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
Bits[i] &= RHS.Bits[i];
// Any bits that are just in this bitvector become zero, because they aren't
// in the RHS bit vector. Any words only in RHS are ignored because they
// are already zero in the LHS.
for (; i != ThisWords; ++i)
Bits[i] = 0;
return *this;
}
// reset - Reset bits that are set in RHS. Same as *this &= ~RHS.
BitVector &reset(const BitVector &RHS) {
unsigned ThisWords = NumBitWords(size());
unsigned RHSWords = NumBitWords(RHS.size());
unsigned i;
for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
Bits[i] &= ~RHS.Bits[i];
return *this;
}
BitVector &operator|=(const BitVector &RHS) {
if (size() < RHS.size())
resize(RHS.size());
for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i)
Bits[i] |= RHS.Bits[i];
return *this;
}
BitVector &operator^=(const BitVector &RHS) {
if (size() < RHS.size())
resize(RHS.size());
for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i)
Bits[i] ^= RHS.Bits[i];
return *this;
}
// Assignment operator.
const BitVector &operator=(const BitVector &RHS) {
if (this == &RHS) return *this;
Size = RHS.size();
unsigned RHSWords = NumBitWords(Size);
if (Size <= Capacity * BITWORD_SIZE) {
if (Size)
std::memcpy(Bits, RHS.Bits, RHSWords * sizeof(BitWord));
clear_unused_bits();
return *this;
}
// Grow the bitvector to have enough elements.
Capacity = RHSWords;
BitWord *NewBits = (BitWord *)std::malloc(Capacity * sizeof(BitWord));
std::memcpy(NewBits, RHS.Bits, Capacity * sizeof(BitWord));
// Destroy the old bits.
std::free(Bits);
Bits = NewBits;
return *this;
}
void swap(BitVector &RHS) {
std::swap(Bits, RHS.Bits);
std::swap(Size, RHS.Size);
std::swap(Capacity, RHS.Capacity);
}
//===--------------------------------------------------------------------===//
// Portable bit mask operations.
//===--------------------------------------------------------------------===//
//
// These methods all operate on arrays of uint32_t, each holding 32 bits. The
// fixed word size makes it easier to work with literal bit vector constants
// in portable code.
//
// The LSB in each word is the lowest numbered bit. The size of a portable
// bit mask is always a whole multiple of 32 bits. If no bit mask size is
// given, the bit mask is assumed to cover the entire BitVector.
/// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize.
/// This computes "*this |= Mask".
void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
applyMask<true, false>(Mask, MaskWords);
}
/// clearBitsInMask - Clear any bits in this vector that are set in Mask.
/// Don't resize. This computes "*this &= ~Mask".
void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
applyMask<false, false>(Mask, MaskWords);
}
/// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask.
/// Don't resize. This computes "*this |= ~Mask".
void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
applyMask<true, true>(Mask, MaskWords);
}
/// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask.
/// Don't resize. This computes "*this &= Mask".
void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
applyMask<false, true>(Mask, MaskWords);
}
private:
unsigned NumBitWords(unsigned S) const {
return (S + BITWORD_SIZE-1) / BITWORD_SIZE;
}
// Set the unused bits in the high words.
void set_unused_bits(bool t = true) {
// Set high words first.
unsigned UsedWords = NumBitWords(Size);
if (Capacity > UsedWords)
init_words(&Bits[UsedWords], (Capacity-UsedWords), t);
// Then set any stray high bits of the last used word.
unsigned ExtraBits = Size % BITWORD_SIZE;
if (ExtraBits) {
Bits[UsedWords-1] &= ~(~0L << ExtraBits);
Bits[UsedWords-1] |= (0 - (BitWord)t) << ExtraBits;
}
}
// Clear the unused bits in the high words.
void clear_unused_bits() {
set_unused_bits(false);
}
void grow(unsigned NewSize) {
Capacity = std::max(NumBitWords(NewSize), Capacity * 2);
Bits = (BitWord *)std::realloc(Bits, Capacity * sizeof(BitWord));
clear_unused_bits();
}
void init_words(BitWord *B, unsigned NumWords, bool t) {
memset(B, 0 - (int)t, NumWords*sizeof(BitWord));
}
template<bool AddBits, bool InvertMask>
void applyMask(const uint32_t *Mask, unsigned MaskWords) {
assert(BITWORD_SIZE % 32 == 0 && "Unsupported BitWord size.");
MaskWords = std::min(MaskWords, (size() + 31) / 32);
const unsigned Scale = BITWORD_SIZE / 32;
unsigned i;
for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) {
BitWord BW = Bits[i];
// This inner loop should unroll completely when BITWORD_SIZE > 32.
for (unsigned b = 0; b != BITWORD_SIZE; b += 32) {
uint32_t M = *Mask++;
if (InvertMask) M = ~M;
if (AddBits) BW |= BitWord(M) << b;
else BW &= ~(BitWord(M) << b);
}
Bits[i] = BW;
}
for (unsigned b = 0; MaskWords; b += 32, --MaskWords) {
uint32_t M = *Mask++;
if (InvertMask) M = ~M;
if (AddBits) Bits[i] |= BitWord(M) << b;
else Bits[i] &= ~(BitWord(M) << b);
}
if (AddBits)
clear_unused_bits();
}
};
} // End llvm namespace
namespace std {
/// Implement std::swap in terms of BitVector swap.
inline void
swap(llvm::BitVector &LHS, llvm::BitVector &RHS) {
LHS.swap(RHS);
}
}
#endif