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add u64 and u128 backends on x64 (no tests)

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nora 2022-04-04 08:44:57 +02:00
parent 0198ef2cdb
commit 6bfa3ef74a
1 changed files with 38 additions and 4 deletions
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42
src/backend.rs
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@ -8,8 +8,6 @@ pub trait Backend<T> {
fn set_ptr(provenance: *mut T, addr: Self) -> Self::Stored;
fn get_int(s: Self::Stored) -> Self;
fn set_int(s: Self::Stored, int: Self) -> Self::Stored;
}
impl<T> Backend<T> for usize {
@ -26,8 +24,44 @@ impl<T> Backend<T> for usize {
fn get_int(s: Self::Stored) -> Self {
Strict::addr(s)
}
}
fn set_int(s: Self::Stored, int: Self) -> Self::Stored {
Strict::with_addr(s, int)
#[cfg(target_pointer_width = "64")]
/// on 64 bit, we can just treat u64/usize interchangeably, because uintptr_t == size_t in Rust
impl<T> Backend<T> for u64 {
type Stored = *mut T;
fn get_ptr(s: Self::Stored) -> (*mut T, Self) {
(s, Strict::addr(s) as u64)
}
fn set_ptr(provenance: *mut T, addr: Self) -> Self::Stored {
Strict::with_addr(provenance, addr as usize)
}
fn get_int(s: Self::Stored) -> Self {
Strict::addr(s) as u64
}
}
#[cfg(target_pointer_width = "64")]
impl<T> Backend<T> for u128 {
// this one keeps the MSB in the pointer address, and the LSB in the integer
type Stored = (*mut T, u64);
fn get_ptr(s: Self::Stored) -> (*mut T, Self) {
(s.0, Self::get_int(s))
}
fn set_ptr(provenance: *mut T, addr: Self) -> Self::Stored {
let ptr_addr = (addr >> 64) as u64;
let int_addr = addr as u64; // truncate it
(Strict::with_addr(provenance, ptr_addr as usize), int_addr)
}
fn get_int(s: Self::Stored) -> Self {
let ptr_addr = Strict::addr(s.0) as u64;
(u128::from(ptr_addr) << 64) | u128::from(s.1)
}
}