bjoernager/rust
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inhibit layout randomization for Box

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The 8472 2024-08-31 14:43:23 +02:00
parent 1e377c5b9f
commit df20808f4d
3 changed files with 27 additions and 9 deletions
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15
compiler/rustc_abi/src/lib.rs
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@ -43,14 +43,17 @@ bitflags! {
const IS_SIMD = 1 << 1;
const IS_TRANSPARENT = 1 << 2;
// Internal only for now. If true, don't reorder fields.
// On its own it does not prevent ABI optimizations.
const IS_LINEAR = 1 << 3;
// If true, the type's layout can be randomized using
// the seed stored in `ReprOptions.field_shuffle_seed`
// If true, the type's crate has opted into layout randomization.
// Other flags can still inhibit reordering and thus randomization.
// The seed stored in `ReprOptions.field_shuffle_seed`.
const RANDOMIZE_LAYOUT = 1 << 4;
// Any of these flags being set prevent field reordering optimisation.
const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits()
const FIELD_ORDER_UNOPTIMIZABLE = ReprFlags::IS_C.bits()
| ReprFlags::IS_SIMD.bits()
| ReprFlags::IS_LINEAR.bits();
const ABI_UNOPTIMIZABLE = ReprFlags::IS_C.bits() | ReprFlags::IS_SIMD.bits();
}
}
@ -139,10 +142,14 @@ impl ReprOptions {
self.c() || self.int.is_some()
}
pub fn inhibit_newtype_abi_optimization(&self) -> bool {
self.flags.intersects(ReprFlags::ABI_UNOPTIMIZABLE)
}
/// Returns `true` if this `#[repr()]` guarantees a fixed field order,
/// e.g. `repr(C)` or `repr(<int>)`.
pub fn inhibit_struct_field_reordering(&self) -> bool {
self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.int.is_some()
self.flags.intersects(ReprFlags::FIELD_ORDER_UNOPTIMIZABLE) || self.int.is_some()
}
/// Returns `true` if this type is valid for reordering and `-Z randomize-layout`