зеркало из https://github.com/mozilla/gecko-dev.git
Bug 1276908 - Make BitArray use 32 bit words to make it easier to access from JIT code r=terrence
This commit is contained in:
Родитель
f35a9b375c
Коммит
3bda7cae20
|
@ -19,13 +19,16 @@ template <size_t nbits>
|
||||||
class BitArray
|
class BitArray
|
||||||
{
|
{
|
||||||
private:
|
private:
|
||||||
static const size_t bitsPerElement = sizeof(uintptr_t) * CHAR_BIT;
|
// Use a 32 bit word to make it easier to access a BitArray from JIT code.
|
||||||
|
using WordT = uint32_t;
|
||||||
|
|
||||||
|
static const size_t bitsPerElement = sizeof(WordT) * CHAR_BIT;
|
||||||
static const size_t numSlots = nbits / bitsPerElement + (nbits % bitsPerElement == 0 ? 0 : 1);
|
static const size_t numSlots = nbits / bitsPerElement + (nbits % bitsPerElement == 0 ? 0 : 1);
|
||||||
static const size_t paddingBits = (numSlots * bitsPerElement) - nbits;
|
static const size_t paddingBits = (numSlots * bitsPerElement) - nbits;
|
||||||
static_assert(paddingBits < bitsPerElement, "More padding bits than expected.");
|
static_assert(paddingBits < bitsPerElement, "More padding bits than expected.");
|
||||||
static const uintptr_t paddingMask = uintptr_t(-1) >> paddingBits;
|
static const WordT paddingMask = WordT(-1) >> paddingBits;
|
||||||
|
|
||||||
uintptr_t map[numSlots];
|
WordT map[numSlots];
|
||||||
|
|
||||||
public:
|
public:
|
||||||
void clear(bool value) {
|
void clear(bool value) {
|
||||||
|
@ -35,20 +38,23 @@ class BitArray
|
||||||
}
|
}
|
||||||
|
|
||||||
inline bool get(size_t offset) const {
|
inline bool get(size_t offset) const {
|
||||||
uintptr_t index, mask;
|
size_t index;
|
||||||
getMarkWordAndMask(offset, &index, &mask);
|
WordT mask;
|
||||||
|
getIndexAndMask(offset, &index, &mask);
|
||||||
return map[index] & mask;
|
return map[index] & mask;
|
||||||
}
|
}
|
||||||
|
|
||||||
void set(size_t offset) {
|
void set(size_t offset) {
|
||||||
uintptr_t index, mask;
|
size_t index;
|
||||||
getMarkWordAndMask(offset, &index, &mask);
|
WordT mask;
|
||||||
|
getIndexAndMask(offset, &index, &mask);
|
||||||
map[index] |= mask;
|
map[index] |= mask;
|
||||||
}
|
}
|
||||||
|
|
||||||
void unset(size_t offset) {
|
void unset(size_t offset) {
|
||||||
uintptr_t index, mask;
|
size_t index;
|
||||||
getMarkWordAndMask(offset, &index, &mask);
|
WordT mask;
|
||||||
|
getIndexAndMask(offset, &index, &mask);
|
||||||
map[index] &= ~mask;
|
map[index] &= ~mask;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -60,13 +66,14 @@ class BitArray
|
||||||
return true;
|
return true;
|
||||||
}
|
}
|
||||||
|
|
||||||
private:
|
static void getIndexAndMask(size_t offset, size_t* indexp, WordT* maskp) {
|
||||||
inline void getMarkWordAndMask(size_t offset,
|
static_assert(bitsPerElement == 32, "unexpected bitsPerElement value");
|
||||||
uintptr_t* indexp, uintptr_t* maskp) const {
|
|
||||||
static_assert(bitsPerElement == 32 || bitsPerElement == 64,
|
|
||||||
"unexpected bitsPerElement value");
|
|
||||||
*indexp = offset / bitsPerElement;
|
*indexp = offset / bitsPerElement;
|
||||||
*maskp = uintptr_t(1) << (offset % bitsPerElement);
|
*maskp = WordT(1) << (offset % bitsPerElement);
|
||||||
|
}
|
||||||
|
|
||||||
|
static size_t offsetOfMap() {
|
||||||
|
return offsetof(BitArray<nbits>, map);
|
||||||
}
|
}
|
||||||
};
|
};
|
||||||
|
|
||||||
|
|
Загрузка…
Ссылка в новой задаче