diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc/Cargo.toml | 1 | ||||
| -rw-r--r-- | compiler/rustc_abi/src/layout.rs | 11 | ||||
| -rw-r--r-- | compiler/rustc_abi/src/lib.rs | 15 | ||||
| -rw-r--r-- | compiler/rustc_driver_impl/Cargo.toml | 5 | ||||
| -rw-r--r-- | compiler/rustc_index/Cargo.toml | 1 | ||||
| -rw-r--r-- | compiler/rustc_index/src/lib.rs | 11 | ||||
| -rw-r--r-- | compiler/rustc_middle/Cargo.toml | 1 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/query/plumbing.rs | 1 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/ty/mod.rs | 10 |
9 files changed, 47 insertions, 9 deletions
diff --git a/compiler/rustc/Cargo.toml b/compiler/rustc/Cargo.toml index 5008069542f..a2fc9d5c408 100644 --- a/compiler/rustc/Cargo.toml +++ b/compiler/rustc/Cargo.toml @@ -30,5 +30,6 @@ features = ['unprefixed_malloc_on_supported_platforms'] jemalloc = ['dep:jemalloc-sys'] llvm = ['rustc_driver_impl/llvm'] max_level_info = ['rustc_driver_impl/max_level_info'] +rustc_randomized_layouts = ['rustc_driver_impl/rustc_randomized_layouts'] rustc_use_parallel_compiler = ['rustc_driver_impl/rustc_use_parallel_compiler'] # tidy-alphabetical-end diff --git a/compiler/rustc_abi/src/layout.rs b/compiler/rustc_abi/src/layout.rs index 5160b4ed0a2..7432768be4a 100644 --- a/compiler/rustc_abi/src/layout.rs +++ b/compiler/rustc_abi/src/layout.rs @@ -968,8 +968,8 @@ fn univariant< let mut align = if pack.is_some() { dl.i8_align } else { dl.aggregate_align }; let mut max_repr_align = repr.align; let mut inverse_memory_index: IndexVec<u32, FieldIdx> = fields.indices().collect(); - let optimize = !repr.inhibit_struct_field_reordering(); - if optimize && fields.len() > 1 { + let optimize_field_order = !repr.inhibit_struct_field_reordering(); + if optimize_field_order && fields.len() > 1 { let end = if let StructKind::MaybeUnsized = kind { fields.len() - 1 } else { fields.len() }; let optimizing = &mut inverse_memory_index.raw[..end]; let fields_excluding_tail = &fields.raw[..end]; @@ -1176,7 +1176,7 @@ fn univariant< // If field 5 has offset 0, offsets[0] is 5, and memory_index[5] should be 0. // Field 5 would be the first element, so memory_index is i: // Note: if we didn't optimize, it's already right. - let memory_index = if optimize { + let memory_index = if optimize_field_order { inverse_memory_index.invert_bijective_mapping() } else { debug_assert!(inverse_memory_index.iter().copied().eq(fields.indices())); @@ -1189,6 +1189,9 @@ fn univariant< } let mut layout_of_single_non_zst_field = None; let mut abi = Abi::Aggregate { sized }; + + let optimize_abi = !repr.inhibit_newtype_abi_optimization(); + // Try to make this a Scalar/ScalarPair. if sized && size.bytes() > 0 { // We skip *all* ZST here and later check if we are good in terms of alignment. @@ -1205,7 +1208,7 @@ fn univariant< match field.abi { // For plain scalars, or vectors of them, we can't unpack // newtypes for `#[repr(C)]`, as that affects C ABIs. - Abi::Scalar(_) | Abi::Vector { .. } if optimize => { + Abi::Scalar(_) | Abi::Vector { .. } if optimize_abi => { abi = field.abi; } // But scalar pairs are Rust-specific and get diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs index df29b3d54f0..be42bc84932 100644 --- a/compiler/rustc_abi/src/lib.rs +++ b/compiler/rustc_abi/src/lib.rs @@ -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` diff --git a/compiler/rustc_driver_impl/Cargo.toml b/compiler/rustc_driver_impl/Cargo.toml index 91cbffcd707..6d6d3f35a4b 100644 --- a/compiler/rustc_driver_impl/Cargo.toml +++ b/compiler/rustc_driver_impl/Cargo.toml @@ -23,6 +23,7 @@ rustc_hir_analysis = { path = "../rustc_hir_analysis" } rustc_hir_pretty = { path = "../rustc_hir_pretty" } rustc_hir_typeck = { path = "../rustc_hir_typeck" } rustc_incremental = { path = "../rustc_incremental" } +rustc_index = { path = "../rustc_index" } rustc_infer = { path = "../rustc_infer" } rustc_interface = { path = "../rustc_interface" } rustc_lint = { path = "../rustc_lint" } @@ -72,6 +73,10 @@ ctrlc = "3.4.4" # tidy-alphabetical-start llvm = ['rustc_interface/llvm'] max_level_info = ['rustc_log/max_level_info'] +rustc_randomized_layouts = [ + 'rustc_index/rustc_randomized_layouts', + 'rustc_middle/rustc_randomized_layouts' +] rustc_use_parallel_compiler = [ 'rustc_data_structures/rustc_use_parallel_compiler', 'rustc_interface/rustc_use_parallel_compiler', diff --git a/compiler/rustc_index/Cargo.toml b/compiler/rustc_index/Cargo.toml index 92ea3f278dc..f7d18f84e34 100644 --- a/compiler/rustc_index/Cargo.toml +++ b/compiler/rustc_index/Cargo.toml @@ -20,4 +20,5 @@ nightly = [ "dep:rustc_macros", "rustc_index_macros/nightly", ] +rustc_randomized_layouts = [] # tidy-alphabetical-end diff --git a/compiler/rustc_index/src/lib.rs b/compiler/rustc_index/src/lib.rs index f773b5b46ad..52f354b8eca 100644 --- a/compiler/rustc_index/src/lib.rs +++ b/compiler/rustc_index/src/lib.rs @@ -33,8 +33,19 @@ pub use vec::IndexVec; /// /// </div> #[macro_export] +#[cfg(not(feature = "rustc_randomized_layouts"))] macro_rules! static_assert_size { ($ty:ty, $size:expr) => { const _: [(); $size] = [(); ::std::mem::size_of::<$ty>()]; }; } + +#[macro_export] +#[cfg(feature = "rustc_randomized_layouts")] +macro_rules! static_assert_size { + ($ty:ty, $size:expr) => { + // no effect other than using the statements. + // struct sizes are not deterministic under randomized layouts + const _: (usize, usize) = ($size, ::std::mem::size_of::<$ty>()); + }; +} diff --git a/compiler/rustc_middle/Cargo.toml b/compiler/rustc_middle/Cargo.toml index 69e3b703cce..b23589afb58 100644 --- a/compiler/rustc_middle/Cargo.toml +++ b/compiler/rustc_middle/Cargo.toml @@ -40,5 +40,6 @@ tracing = "0.1" [features] # tidy-alphabetical-start +rustc_randomized_layouts = [] rustc_use_parallel_compiler = ["dep:rustc-rayon-core"] # tidy-alphabetical-end diff --git a/compiler/rustc_middle/src/query/plumbing.rs b/compiler/rustc_middle/src/query/plumbing.rs index c9bd702cce3..0320a91d142 100644 --- a/compiler/rustc_middle/src/query/plumbing.rs +++ b/compiler/rustc_middle/src/query/plumbing.rs @@ -337,6 +337,7 @@ macro_rules! define_callbacks { // Ensure that values grow no larger than 64 bytes by accident. // Increase this limit if necessary, but do try to keep the size low if possible #[cfg(target_pointer_width = "64")] + #[cfg(not(feature = "rustc_randomized_layouts"))] const _: () = { if mem::size_of::<Value<'static>>() > 64 { panic!("{}", concat!( diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs index cd94c0afad0..ee70a6346d9 100644 --- a/compiler/rustc_middle/src/ty/mod.rs +++ b/compiler/rustc_middle/src/ty/mod.rs @@ -35,6 +35,7 @@ use rustc_data_structures::tagged_ptr::CopyTaggedPtr; use rustc_errors::{Diag, ErrorGuaranteed, StashKey}; use rustc_hir::def::{CtorKind, CtorOf, DefKind, DocLinkResMap, LifetimeRes, Res}; use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LocalDefIdMap}; +use rustc_hir::LangItem; use rustc_index::IndexVec; use rustc_macros::{ extension, Decodable, Encodable, HashStable, TyDecodable, TyEncodable, TypeFoldable, @@ -1570,8 +1571,15 @@ impl<'tcx> TyCtxt<'tcx> { flags.insert(ReprFlags::RANDOMIZE_LAYOUT); } + // box is special, on the one hand the compiler assumes an ordered layout, with the pointer + // always at offset zero. On the other hand we want scalar abi optimizations. + let is_box = self.is_lang_item(did.to_def_id(), LangItem::OwnedBox); + // This is here instead of layout because the choice must make it into metadata. - if !self.consider_optimizing(|| format!("Reorder fields of {:?}", self.def_path_str(did))) { + if is_box + || !self + .consider_optimizing(|| format!("Reorder fields of {:?}", self.def_path_str(did))) + { flags.insert(ReprFlags::IS_LINEAR); } |