[llvm] r301031 - [BitVector] Make BitVector store an ArrayRef.
Zachary Turner via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 21 13:12:08 PDT 2017
Author: zturner
Date: Fri Apr 21 15:12:08 2017
New Revision: 301031
URL: http://llvm.org/viewvc/llvm-project?rev=301031&view=rev
Log:
[BitVector] Make BitVector store an ArrayRef.
This makes certain operations on the underlying storage
easier since we have access to ArrayRef methods such as
drop_front, drop_back, slice, range-based for loops, etc.
Differential Revision: https://reviews.llvm.org/D32367
Modified:
llvm/trunk/include/llvm/ADT/BitVector.h
Modified: llvm/trunk/include/llvm/ADT/BitVector.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/BitVector.h?rev=301031&r1=301030&r2=301031&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/BitVector.h (original)
+++ llvm/trunk/include/llvm/ADT/BitVector.h Fri Apr 21 15:12:08 2017
@@ -34,9 +34,8 @@ class BitVector {
static_assert(BITWORD_SIZE == 64 || BITWORD_SIZE == 32,
"Unsupported word size");
- BitWord *Bits; // Actual bits.
- unsigned Size; // Size of bitvector in bits.
- unsigned Capacity; // Number of BitWords allocated in the Bits array.
+ MutableArrayRef<BitWord> Bits; // Actual bits.
+ unsigned Size; // Size of bitvector in bits.
public:
typedef unsigned size_type;
@@ -76,16 +75,14 @@ public:
/// BitVector default ctor - Creates an empty bitvector.
- BitVector() : Size(0), Capacity(0) {
- Bits = nullptr;
- }
+ BitVector() : Size(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);
+ size_t Capacity = NumBitWords(s);
+ Bits = allocate(Capacity);
+ init_words(Bits, t);
if (t)
clear_unused_bits();
}
@@ -93,25 +90,21 @@ public:
/// BitVector copy ctor.
BitVector(const BitVector &RHS) : Size(RHS.size()) {
if (Size == 0) {
- Bits = nullptr;
- Capacity = 0;
+ Bits = MutableArrayRef<BitWord>();
return;
}
- Capacity = NumBitWords(RHS.size());
- Bits = (BitWord *)std::malloc(Capacity * sizeof(BitWord));
- std::memcpy(Bits, RHS.Bits, Capacity * sizeof(BitWord));
+ size_t Capacity = NumBitWords(RHS.size());
+ Bits = allocate(Capacity);
+ std::memcpy(Bits.data(), RHS.Bits.data(), Capacity * sizeof(BitWord));
}
- BitVector(BitVector &&RHS)
- : Bits(RHS.Bits), Size(RHS.Size), Capacity(RHS.Capacity) {
- RHS.Bits = nullptr;
- RHS.Size = RHS.Capacity = 0;
+ BitVector(BitVector &&RHS) : Bits(RHS.Bits), Size(RHS.Size) {
+ RHS.Bits = MutableArrayRef<BitWord>();
+ RHS.Size = 0;
}
- ~BitVector() {
- std::free(Bits);
- }
+ ~BitVector() { std::free(Bits.data()); }
/// empty - Tests whether there are no bits in this bitvector.
bool empty() const { return Size == 0; }
@@ -267,10 +260,10 @@ public:
/// resize - Grow or shrink the bitvector.
void resize(unsigned N, bool t = false) {
- if (N > Capacity * BITWORD_SIZE) {
- unsigned OldCapacity = Capacity;
+ if (N > getBitCapacity()) {
+ unsigned OldCapacity = Bits.size();
grow(N);
- init_words(&Bits[OldCapacity], (Capacity-OldCapacity), t);
+ init_words(Bits.drop_front(OldCapacity), t);
}
// Set any old unused bits that are now included in the BitVector. This
@@ -287,19 +280,19 @@ public:
}
void reserve(unsigned N) {
- if (N > Capacity * BITWORD_SIZE)
+ if (N > getBitCapacity())
grow(N);
}
// Set, reset, flip
BitVector &set() {
- init_words(Bits, Capacity, true);
+ init_words(Bits, true);
clear_unused_bits();
return *this;
}
BitVector &set(unsigned Idx) {
- assert(Bits && "Bits never allocated");
+ assert(Bits.data() && "Bits never allocated");
Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE);
return *this;
}
@@ -334,7 +327,7 @@ public:
}
BitVector &reset() {
- init_words(Bits, Capacity, false);
+ init_words(Bits, false);
return *this;
}
@@ -601,21 +594,21 @@ public:
Size = RHS.size();
unsigned RHSWords = NumBitWords(Size);
- if (Size <= Capacity * BITWORD_SIZE) {
+ if (Size <= getBitCapacity()) {
if (Size)
- std::memcpy(Bits, RHS.Bits, RHSWords * sizeof(BitWord));
+ std::memcpy(Bits.data(), RHS.Bits.data(), RHSWords * sizeof(BitWord));
clear_unused_bits();
return *this;
}
// Grow the bitvector to have enough elements.
- Capacity = RHSWords;
- assert(Capacity > 0 && "negative capacity?");
- BitWord *NewBits = (BitWord *)std::malloc(Capacity * sizeof(BitWord));
- std::memcpy(NewBits, RHS.Bits, Capacity * sizeof(BitWord));
+ unsigned NewCapacity = RHSWords;
+ assert(NewCapacity > 0 && "negative capacity?");
+ auto NewBits = allocate(NewCapacity);
+ std::memcpy(NewBits.data(), RHS.Bits.data(), NewCapacity * sizeof(BitWord));
// Destroy the old bits.
- std::free(Bits);
+ std::free(Bits.data());
Bits = NewBits;
return *this;
@@ -624,13 +617,12 @@ public:
const BitVector &operator=(BitVector &&RHS) {
if (this == &RHS) return *this;
- std::free(Bits);
+ std::free(Bits.data());
Bits = RHS.Bits;
Size = RHS.Size;
- Capacity = RHS.Capacity;
- RHS.Bits = nullptr;
- RHS.Size = RHS.Capacity = 0;
+ RHS.Bits = MutableArrayRef<BitWord>();
+ RHS.Size = 0;
return *this;
}
@@ -638,7 +630,6 @@ public:
void swap(BitVector &RHS) {
std::swap(Bits, RHS.Bits);
std::swap(Size, RHS.Size);
- std::swap(Capacity, RHS.Capacity);
}
//===--------------------------------------------------------------------===//
@@ -698,14 +689,14 @@ private:
uint32_t NumWords = NumBitWords(Size);
- auto Src = ArrayRef<BitWord>(Bits, NumWords).drop_back(Count);
- auto Dest = MutableArrayRef<BitWord>(Bits, NumWords).drop_front(Count);
+ auto Src = Bits.take_front(NumWords).drop_back(Count);
+ auto Dest = Bits.take_front(NumWords).drop_front(Count);
// Since we always move Word-sized chunks of data with src and dest both
// aligned to a word-boundary, we don't need to worry about endianness
// here.
std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord));
- std::memset(Bits, 0, Count * sizeof(BitWord));
+ std::memset(Bits.data(), 0, Count * sizeof(BitWord));
clear_unused_bits();
}
@@ -718,14 +709,19 @@ private:
uint32_t NumWords = NumBitWords(Size);
- auto Src = ArrayRef<BitWord>(Bits, NumWords).drop_front(Count);
- auto Dest = MutableArrayRef<BitWord>(Bits, NumWords).drop_back(Count);
+ auto Src = Bits.take_front(NumWords).drop_front(Count);
+ auto Dest = Bits.take_front(NumWords).drop_back(Count);
assert(Dest.size() == Src.size());
std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord));
std::memset(Dest.end(), 0, Count * sizeof(BitWord));
}
+ MutableArrayRef<BitWord> allocate(size_t NumWords) {
+ BitWord *RawBits = (BitWord *)std::malloc(NumWords * sizeof(BitWord));
+ return MutableArrayRef<BitWord>(RawBits, NumWords);
+ }
+
int next_unset_in_word(int WordIndex, BitWord Word) const {
unsigned Result = WordIndex * BITWORD_SIZE + countTrailingOnes(Word);
return Result < size() ? Result : -1;
@@ -739,8 +735,8 @@ private:
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);
+ if (Bits.size() > UsedWords)
+ init_words(Bits.drop_front(UsedWords), t);
// Then set any stray high bits of the last used word.
unsigned ExtraBits = Size % BITWORD_SIZE;
@@ -759,16 +755,17 @@ private:
}
void grow(unsigned NewSize) {
- Capacity = std::max(NumBitWords(NewSize), Capacity * 2);
- assert(Capacity > 0 && "realloc-ing zero space");
- Bits = (BitWord *)std::realloc(Bits, Capacity * sizeof(BitWord));
-
+ unsigned NewCapacity = std::max(NumBitWords(NewSize), Bits.size() * 2);
+ assert(NewCapacity > 0 && "realloc-ing zero space");
+ BitWord *NewBits =
+ (BitWord *)std::realloc(Bits.data(), NewCapacity * sizeof(BitWord));
+ Bits = MutableArrayRef<BitWord>(NewBits, NewCapacity);
clear_unused_bits();
}
- void init_words(BitWord *B, unsigned NumWords, bool t) {
- if (NumWords > 0)
- memset(B, 0 - (int)t, NumWords*sizeof(BitWord));
+ void init_words(MutableArrayRef<BitWord> B, bool t) {
+ if (B.size() > 0)
+ memset(B.data(), 0 - (int)t, B.size() * sizeof(BitWord));
}
template<bool AddBits, bool InvertMask>
@@ -800,7 +797,8 @@ private:
public:
/// Return the size (in bytes) of the bit vector.
- size_t getMemorySize() const { return Capacity * sizeof(BitWord); }
+ size_t getMemorySize() const { return Bits.size() * sizeof(BitWord); }
+ size_t getBitCapacity() const { return Bits.size() * BITWORD_SIZE; }
};
static inline size_t capacity_in_bytes(const BitVector &X) {
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