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Auto merge of #50916 - oli-obk:miri, r=eddyb

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Allow `Size` to be any valid `u64`

cc https://github.com/solson/miri/pull/378#issuecomment-390470725

The alternative is to make mir::interpret's pointer offsets not be `Size`

fixes #50917

r? @eddyb
This commit is contained in:
bors 2018-05-23 20:13:22 +00:00
commit 29ffe51e34
1 changed files with 23 additions and 20 deletions
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43
src/librustc_target/abi/mod.rs
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@ -232,10 +232,7 @@ impl Size {
Size::from_bytes(bits / 8 + ((bits % 8) + 7) / 8)
}
pub fn from_bytes(bytes: u64) -> Size {
if bytes >= (1 << 61) {
panic!("Size::from_bytes: {} bytes in bits doesn't fit in u64", bytes)
}
pub const fn from_bytes(bytes: u64) -> Size {
Size {
raw: bytes
}
@ -246,7 +243,9 @@ impl Size {
}
pub fn bits(self) -> u64 {
self.bytes() * 8
self.bytes().checked_mul(8).unwrap_or_else(|| {
panic!("Size::bits: {} bytes in bits doesn't fit in u64", self.bytes())
})
}
pub fn abi_align(self, align: Align) -> Size {
@ -262,9 +261,7 @@ impl Size {
pub fn checked_add<C: HasDataLayout>(self, offset: Size, cx: C) -> Option<Size> {
let dl = cx.data_layout();
// Each Size is less than dl.obj_size_bound(), so the sum is
// also less than 1 << 62 (and therefore can't overflow).
let bytes = self.bytes() + offset.bytes();
let bytes = self.bytes().checked_add(offset.bytes())?;
if bytes < dl.obj_size_bound() {
Some(Size::from_bytes(bytes))
@ -276,11 +273,11 @@ impl Size {
pub fn checked_mul<C: HasDataLayout>(self, count: u64, cx: C) -> Option<Size> {
let dl = cx.data_layout();
match self.bytes().checked_mul(count) {
Some(bytes) if bytes < dl.obj_size_bound() => {
Some(Size::from_bytes(bytes))
}
_ => None
let bytes = self.bytes().checked_mul(count)?;
if bytes < dl.obj_size_bound() {
Some(Size::from_bytes(bytes))
} else {
None
}
}
}
@ -291,19 +288,25 @@ impl Size {
impl Add for Size {
type Output = Size;
fn add(self, other: Size) -> Size {
// Each Size is less than 1 << 61, so the sum is
// less than 1 << 62 (and therefore can't overflow).
Size::from_bytes(self.bytes() + other.bytes())
Size::from_bytes(self.bytes().checked_add(other.bytes()).unwrap_or_else(|| {
panic!("Size::add: {} + {} doesn't fit in u64", self.bytes(), other.bytes())
}))
}
}
impl Sub for Size {
type Output = Size;
fn sub(self, other: Size) -> Size {
// Each Size is less than 1 << 61, so an underflow
// would result in a value larger than 1 << 61,
// which Size::from_bytes will catch for us.
Size::from_bytes(self.bytes() - other.bytes())
Size::from_bytes(self.bytes().checked_sub(other.bytes()).unwrap_or_else(|| {
panic!("Size::sub: {} - {} would result in negative size", self.bytes(), other.bytes())
}))
}
}
impl Mul<Size> for u64 {
type Output = Size;
fn mul(self, size: Size) -> Size {
size * self
}
}