[llvm-commits] [llvm] r102707 - /llvm/trunk/include/llvm/ADT/SmallBitVector.h
Benjamin Kramer
benny.kra at googlemail.com
Fri Apr 30 04:34:01 PDT 2010
Author: d0k
Date: Fri Apr 30 06:34:01 2010
New Revision: 102707
URL: http://llvm.org/viewvc/llvm-project?rev=102707&view=rev
Log:
Make sure SmallBitVector actually uses the small case and fix latent bugs.
- We can't use PointerIntPair here since we require the discrimination bit to be in the LSB.
Modified:
llvm/trunk/include/llvm/ADT/SmallBitVector.h
Modified: llvm/trunk/include/llvm/ADT/SmallBitVector.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/SmallBitVector.h?rev=102707&r1=102706&r2=102707&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/SmallBitVector.h (original)
+++ llvm/trunk/include/llvm/ADT/SmallBitVector.h Fri Apr 30 06:34:01 2010
@@ -15,7 +15,6 @@
#define LLVM_ADT_SMALLBITVECTOR_H
#include "llvm/ADT/BitVector.h"
-#include "llvm/ADT/PointerIntPair.h"
#include "llvm/Support/MathExtras.h"
#include <cassert>
@@ -32,48 +31,57 @@
// TODO: In "large" mode, a pointer to a BitVector is used, leading to an
// unnecessary level of indirection. It would be more efficient to use a
// pointer to memory containing size, allocation size, and the array of bits.
- PointerIntPair<BitVector *, 1, uintptr_t> X;
+ uintptr_t X;
- // The number of bits in this class.
- static const size_t NumBaseBits = sizeof(uintptr_t) * CHAR_BIT;
-
- // One bit is used to discriminate between small and large mode. The
- // remaining bits are used for the small-mode representation.
- static const size_t SmallNumRawBits = NumBaseBits - 1;
-
- // A few more bits are used to store the size of the bit set in small mode.
- // Theoretically this is a ceil-log2. These bits are encoded in the most
- // significant bits of the raw bits.
- static const size_t SmallNumSizeBits = (NumBaseBits == 32 ? 5 :
- NumBaseBits == 64 ? 6 :
- SmallNumRawBits);
-
- // The remaining bits are used to store the actual set in small mode.
- static const size_t SmallNumDataBits = SmallNumRawBits - SmallNumSizeBits;
+ enum {
+ // The number of bits in this class.
+ NumBaseBits = sizeof(uintptr_t) * CHAR_BIT,
+
+ // One bit is used to discriminate between small and large mode. The
+ // remaining bits are used for the small-mode representation.
+ SmallNumRawBits = NumBaseBits - 1,
+
+ // A few more bits are used to store the size of the bit set in small mode.
+ // Theoretically this is a ceil-log2. These bits are encoded in the most
+ // significant bits of the raw bits.
+ SmallNumSizeBits = (NumBaseBits == 32 ? 5 :
+ NumBaseBits == 64 ? 6 :
+ SmallNumRawBits),
+
+ // The remaining bits are used to store the actual set in small mode.
+ SmallNumDataBits = SmallNumRawBits - SmallNumSizeBits
+ };
bool isSmall() const {
- return X.getInt();
+ return X & uintptr_t(1);
+ }
+
+ BitVector *getPointer() const {
+ assert(!isSmall());
+ return reinterpret_cast<BitVector *>(X);
}
void switchToSmall(uintptr_t NewSmallBits, size_t NewSize) {
- X.setInt(true);
+ X = 1;
setSmallSize(NewSize);
setSmallBits(NewSmallBits);
}
void switchToLarge(BitVector *BV) {
- X.setInt(false);
- X.setPointer(BV);
+ X = reinterpret_cast<uintptr_t>(BV);
+ assert(!isSmall() && "Tried to use an unaligned pointer");
}
// Return all the bits used for the "small" representation; this includes
// bits for the size as well as the element bits.
uintptr_t getSmallRawBits() const {
- return reinterpret_cast<uintptr_t>(X.getPointer()) >> 1;
+ assert(isSmall());
+ return X >> 1;
}
void setSmallRawBits(uintptr_t NewRawBits) {
- return X.setPointer(reinterpret_cast<BitVector *>(NewRawBits << 1));
+ assert(isSmall());
+ X = NewRawBits << 1 | uintptr_t(1);
}
// Return the size.
@@ -87,22 +95,22 @@
// Return the element bits.
uintptr_t getSmallBits() const {
- return getSmallRawBits() & ~(~uintptr_t(0) << SmallNumDataBits);
+ return getSmallRawBits() & ~(~uintptr_t(0) << getSmallSize());
}
void setSmallBits(uintptr_t NewBits) {
- setSmallRawBits((getSmallRawBits() & (~uintptr_t(0) << SmallNumDataBits)) |
- (NewBits & ~(~uintptr_t(0) << getSmallSize())));
+ setSmallRawBits(NewBits & ~(~uintptr_t(0) << getSmallSize()) |
+ (getSmallSize() << SmallNumDataBits));
}
public:
/// SmallBitVector default ctor - Creates an empty bitvector.
- SmallBitVector() : X(0, 1) {}
+ SmallBitVector() : X(1) {}
/// SmallBitVector ctor - Creates a bitvector of specified number of bits. All
/// bits are initialized to the specified value.
- explicit SmallBitVector(unsigned s, bool t = false) : X(0, 1) {
- if (s <= SmallNumRawBits)
+ explicit SmallBitVector(unsigned s, bool t = false) {
+ if (s <= SmallNumDataBits)
switchToSmall(t ? ~uintptr_t(0) : 0, s);
else
switchToLarge(new BitVector(s, t));
@@ -113,22 +121,22 @@
if (RHS.isSmall())
X = RHS.X;
else
- switchToLarge(new BitVector(*RHS.X.getPointer()));
+ switchToLarge(new BitVector(*RHS.getPointer()));
}
~SmallBitVector() {
if (!isSmall())
- delete X.getPointer();
+ delete getPointer();
}
/// empty - Tests whether there are no bits in this bitvector.
bool empty() const {
- return isSmall() ? getSmallSize() == 0 : X.getPointer()->empty();
+ return isSmall() ? getSmallSize() == 0 : getPointer()->empty();
}
/// size - Returns the number of bits in this bitvector.
size_t size() const {
- return isSmall() ? getSmallSize() : X.getPointer()->size();
+ return isSmall() ? getSmallSize() : getPointer()->size();
}
/// count - Returns the number of bits which are set.
@@ -141,21 +149,21 @@
return CountPopulation_64(Bits);
assert(0 && "Unsupported!");
}
- return X.getPointer()->count();
+ return getPointer()->count();
}
/// any - Returns true if any bit is set.
bool any() const {
if (isSmall())
return getSmallBits() != 0;
- return X.getPointer()->any();
+ return getPointer()->any();
}
/// none - Returns true if none of the bits are set.
bool none() const {
if (isSmall())
return getSmallBits() == 0;
- return X.getPointer()->none();
+ return getPointer()->none();
}
/// find_first - Returns the index of the first set bit, -1 if none
@@ -163,13 +171,16 @@
int find_first() const {
if (isSmall()) {
uintptr_t Bits = getSmallBits();
- if (sizeof(uintptr_t) * CHAR_BIT == 32)
- return CountTrailingZeros_32(Bits);
- if (sizeof(uintptr_t) * CHAR_BIT == 64)
- return CountTrailingZeros_64(Bits);
+ if (sizeof(uintptr_t) * CHAR_BIT == 32) {
+ size_t FirstBit = CountTrailingZeros_32(Bits);
+ return FirstBit == 32 ? -1 : FirstBit;
+ } else if (sizeof(uintptr_t) * CHAR_BIT == 64) {
+ size_t FirstBit = CountTrailingZeros_64(Bits);
+ return FirstBit == 64 ? -1 : FirstBit;
+ }
assert(0 && "Unsupported!");
}
- return X.getPointer()->find_first();
+ return getPointer()->find_first();
}
/// find_next - Returns the index of the next set bit following the
@@ -178,30 +189,34 @@
if (isSmall()) {
uintptr_t Bits = getSmallBits();
// Mask off previous bits.
- Bits &= ~uintptr_t(0) << Prev;
- if (sizeof(uintptr_t) * CHAR_BIT == 32)
- return CountTrailingZeros_32(Bits);
- if (sizeof(uintptr_t) * CHAR_BIT == 64)
- return CountTrailingZeros_64(Bits);
+ Bits &= ~uintptr_t(0) << (Prev + 1);
+ if (sizeof(uintptr_t) * CHAR_BIT == 32) {
+ size_t FirstBit = CountTrailingZeros_32(Bits);
+ return FirstBit == 32 ? -1 : FirstBit;
+ } else if (sizeof(uintptr_t) * CHAR_BIT == 64) {
+ size_t FirstBit = CountTrailingZeros_64(Bits);
+ return FirstBit == 64 ? -1 : FirstBit;
+ }
assert(0 && "Unsupported!");
}
- return X.getPointer()->find_next(Prev);
+ return getPointer()->find_next(Prev);
}
/// clear - Clear all bits.
void clear() {
if (!isSmall())
- delete X.getPointer();
+ delete getPointer();
switchToSmall(0, 0);
}
/// resize - Grow or shrink the bitvector.
void resize(unsigned N, bool t = false) {
if (!isSmall()) {
- X.getPointer()->resize(N, t);
- } else if (getSmallSize() >= N) {
+ getPointer()->resize(N, t);
+ } else if (SmallNumDataBits >= N) {
+ uintptr_t NewBits = t ? ~uintptr_t(0) << getSmallSize() : 0;
setSmallSize(N);
- setSmallBits(getSmallBits());
+ setSmallBits(NewBits | getSmallBits());
} else {
BitVector *BV = new BitVector(N, t);
uintptr_t OldBits = getSmallBits();
@@ -224,7 +239,7 @@
switchToLarge(BV);
}
} else {
- X.getPointer()->reserve(N);
+ getPointer()->reserve(N);
}
}
@@ -233,7 +248,7 @@
if (isSmall())
setSmallBits(~uintptr_t(0));
else
- X.getPointer()->set();
+ getPointer()->set();
return *this;
}
@@ -241,7 +256,7 @@
if (isSmall())
setSmallBits(getSmallBits() | (uintptr_t(1) << Idx));
else
- X.getPointer()->set(Idx);
+ getPointer()->set(Idx);
return *this;
}
@@ -249,7 +264,7 @@
if (isSmall())
setSmallBits(0);
else
- X.getPointer()->reset();
+ getPointer()->reset();
return *this;
}
@@ -257,7 +272,7 @@
if (isSmall())
setSmallBits(getSmallBits() & ~(uintptr_t(1) << Idx));
else
- X.getPointer()->reset(Idx);
+ getPointer()->reset(Idx);
return *this;
}
@@ -265,7 +280,7 @@
if (isSmall())
setSmallBits(~getSmallBits());
else
- X.getPointer()->flip();
+ getPointer()->flip();
return *this;
}
@@ -273,7 +288,7 @@
if (isSmall())
setSmallBits(getSmallBits() ^ (uintptr_t(1) << Idx));
else
- X.getPointer()->flip(Idx);
+ getPointer()->flip(Idx);
return *this;
}
@@ -288,7 +303,7 @@
assert(Idx < size() && "Out-of-bounds Bit access.");
if (isSmall())
return ((getSmallBits() >> Idx) & 1) != 0;
- return X.getPointer()->operator[](Idx);
+ return getPointer()->operator[](Idx);
}
bool test(unsigned Idx) const {
@@ -302,7 +317,7 @@
if (isSmall())
return getSmallBits() == RHS.getSmallBits();
else
- return *X.getPointer() == *RHS.X.getPointer();
+ return *getPointer() == *RHS.getPointer();
}
bool operator!=(const SmallBitVector &RHS) const {
@@ -315,11 +330,11 @@
if (isSmall())
setSmallBits(getSmallBits() & RHS.getSmallBits());
else if (!RHS.isSmall())
- X.getPointer()->operator&=(*RHS.X.getPointer());
+ getPointer()->operator&=(*RHS.getPointer());
else {
SmallBitVector Copy = RHS;
Copy.resize(size());
- X.getPointer()->operator&=(*Copy.X.getPointer());
+ getPointer()->operator&=(*Copy.getPointer());
}
return *this;
}
@@ -329,11 +344,11 @@
if (isSmall())
setSmallBits(getSmallBits() | RHS.getSmallBits());
else if (!RHS.isSmall())
- X.getPointer()->operator|=(*RHS.X.getPointer());
+ getPointer()->operator|=(*RHS.getPointer());
else {
SmallBitVector Copy = RHS;
Copy.resize(size());
- X.getPointer()->operator|=(*Copy.X.getPointer());
+ getPointer()->operator|=(*Copy.getPointer());
}
return *this;
}
@@ -343,11 +358,11 @@
if (isSmall())
setSmallBits(getSmallBits() ^ RHS.getSmallBits());
else if (!RHS.isSmall())
- X.getPointer()->operator^=(*RHS.X.getPointer());
+ getPointer()->operator^=(*RHS.getPointer());
else {
SmallBitVector Copy = RHS;
Copy.resize(size());
- X.getPointer()->operator^=(*Copy.X.getPointer());
+ getPointer()->operator^=(*Copy.getPointer());
}
return *this;
}
@@ -358,12 +373,12 @@
if (RHS.isSmall())
X = RHS.X;
else
- switchToLarge(new BitVector(*RHS.X.getPointer()));
+ switchToLarge(new BitVector(*RHS.getPointer()));
} else {
if (!RHS.isSmall())
- *X.getPointer() = *RHS.X.getPointer();
+ *getPointer() = *RHS.getPointer();
else {
- delete X.getPointer();
+ delete getPointer();
X = RHS.X;
}
}
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