diff options
| -rw-r--r-- | src/librustc/mir/interpret/allocation.rs | 49 | ||||
| -rw-r--r-- | src/librustc_mir/interpret/memory.rs | 2 | ||||
| -rw-r--r-- | src/test/run-pass-fulldeps/undef_mask.rs | 2 |
3 files changed, 35 insertions, 18 deletions
diff --git a/src/librustc/mir/interpret/allocation.rs b/src/librustc/mir/interpret/allocation.rs index 18880c551ed..004804f7c21 100644 --- a/src/librustc/mir/interpret/allocation.rs +++ b/src/librustc/mir/interpret/allocation.rs @@ -100,8 +100,7 @@ impl AllocationExtra<(), ()> for () { impl<Tag, Extra> Allocation<Tag, Extra> { /// Creates a read-only allocation initialized by the given bytes pub fn from_bytes(slice: &[u8], align: Align, extra: Extra) -> Self { - let mut undef_mask = UndefMask::new(Size::ZERO); - undef_mask.grow(Size::from_bytes(slice.len() as u64), true); + let undef_mask = UndefMask::new(Size::from_bytes(slice.len() as u64), true); Self { bytes: slice.to_owned(), relocations: Relocations::new(), @@ -121,7 +120,7 @@ impl<Tag, Extra> Allocation<Tag, Extra> { Allocation { bytes: vec![0; size.bytes() as usize], relocations: Relocations::new(), - undef_mask: UndefMask::new(size), + undef_mask: UndefMask::new(size, false), align, mutability: Mutability::Mutable, extra, @@ -625,12 +624,12 @@ impl_stable_hash_for!(struct mir::interpret::UndefMask{blocks, len}); impl UndefMask { pub const BLOCK_SIZE: u64 = 64; - pub fn new(size: Size) -> Self { + pub fn new(size: Size, state: bool) -> Self { let mut m = UndefMask { blocks: vec![], len: Size::ZERO, }; - m.grow(size, false); + m.grow(size, state); m } @@ -667,25 +666,40 @@ impl UndefMask { let (blocka, bita) = bit_index(start); let (blockb, bitb) = bit_index(end); if blocka == blockb { - // within a single block - for i in bita .. bitb { - self.set_bit(blocka, i, new_state); + // first set all bits but the first `bita` + // then unset the last `64 - bitb` bits + let range = if bitb == 0 { + u64::max_value() << bita + } else { + (u64::max_value() << bita) & (u64::max_value() >> (64 - bitb)) + }; + if new_state { + self.blocks[blocka] |= range; + } else { + self.blocks[blocka] &= !range; } return; } // across block boundaries - for i in bita .. Self::BLOCK_SIZE as usize { - self.set_bit(blocka, i, new_state); - } - for i in 0 .. bitb { - self.set_bit(blockb, i, new_state); - } - // fill in all the other blocks (much faster than one bit at a time) if new_state { + // set bita..64 to 1 + self.blocks[blocka] |= u64::max_value() << bita; + // set 0..bitb to 1 + if bitb != 0 { + self.blocks[blockb] |= u64::max_value() >> (64 - bitb); + } + // fill in all the other blocks (much faster than one bit at a time) for block in (blocka + 1) .. blockb { self.blocks[block] = u64::max_value(); } } else { + // set bita..64 to 0 + self.blocks[blocka] &= !(u64::max_value() << bita); + // set 0..bitb to 0 + if bitb != 0 { + self.blocks[blockb] &= !(u64::max_value() >> (64 - bitb)); + } + // fill in all the other blocks (much faster than one bit at a time) for block in (blocka + 1) .. blockb { self.blocks[block] = 0; } @@ -695,7 +709,7 @@ impl UndefMask { #[inline] pub fn get(&self, i: Size) -> bool { let (block, bit) = bit_index(i); - (self.blocks[block] & 1 << bit) != 0 + (self.blocks[block] & (1 << bit)) != 0 } #[inline] @@ -714,6 +728,9 @@ impl UndefMask { } pub fn grow(&mut self, amount: Size, new_state: bool) { + if amount.bytes() == 0 { + return; + } let unused_trailing_bits = self.blocks.len() as u64 * Self::BLOCK_SIZE - self.len.bytes(); if amount.bytes() > unused_trailing_bits { let additional_blocks = amount.bytes() / Self::BLOCK_SIZE + 1; diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs index 6cbb611c1a3..fba0a9af213 100644 --- a/src/librustc_mir/interpret/memory.rs +++ b/src/librustc_mir/interpret/memory.rs @@ -815,7 +815,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> { // an optimization where we can just overwrite an entire range of definedness bits if // they are going to be uniformly `1` or `0`. if ranges.is_empty() { - dest_allocation.undef_mask.set_range( + dest_allocation.undef_mask.set_range_inbounds( dest.offset, dest.offset + size * repeat, first, diff --git a/src/test/run-pass-fulldeps/undef_mask.rs b/src/test/run-pass-fulldeps/undef_mask.rs index 37c44e2df6c..cf6e6f72316 100644 --- a/src/test/run-pass-fulldeps/undef_mask.rs +++ b/src/test/run-pass-fulldeps/undef_mask.rs @@ -9,7 +9,7 @@ use rustc::mir::interpret::UndefMask; use rustc::ty::layout::Size; fn main() { - let mut mask = UndefMask::new(Size::from_bytes(500)); + let mut mask = UndefMask::new(Size::from_bytes(500), false); assert!(!mask.get(Size::from_bytes(499))); mask.set(Size::from_bytes(499), true); assert!(mask.get(Size::from_bytes(499))); |