From 121e9f4cc86104da0209afd3f681dc82da9e3928 Mon Sep 17 00:00:00 2001 From: The 8472 Date: Fri, 2 Sep 2022 20:15:26 +0200 Subject: [PATCH 1/7] Add rust.randomize-layout config to build artifacts with -Zrandomize-layout Additionally teach compiletest to ignore tests that rely on deterministic layout. Tests themselves aren't built with randomization but they can still observe slight changes in std or rustc --- config.example.toml | 3 +++ src/bootstrap/src/core/build_steps/test.rs | 3 +++ src/bootstrap/src/core/builder.rs | 4 ++++ src/bootstrap/src/core/config/config.rs | 7 +++++++ src/tools/compiletest/src/command-list.rs | 1 + src/tools/compiletest/src/common.rs | 3 +++ src/tools/compiletest/src/header/needs.rs | 5 +++++ src/tools/compiletest/src/lib.rs | 6 ++++++ 8 files changed, 32 insertions(+) diff --git a/config.example.toml b/config.example.toml index f1dc32234ccf2..897857f286c11 100644 --- a/config.example.toml +++ b/config.example.toml @@ -512,6 +512,9 @@ # are disabled statically" because `max_level_info` is enabled, set this value to `true`. #debug-logging = rust.debug-assertions (boolean) +# Whether or not to build rustc, tools and the libraries with randomized type layout +#randomize-layout = false + # Whether or not overflow checks are enabled for the compiler and standard # library. # diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs index 84a6b26a491ed..a8e1254047363 100644 --- a/src/bootstrap/src/core/build_steps/test.rs +++ b/src/bootstrap/src/core/build_steps/test.rs @@ -1810,6 +1810,9 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the if builder.config.rust_optimize_tests { cmd.arg("--optimize-tests"); } + if builder.config.rust_randomize_layout { + cmd.arg("--rust-randomized-layout"); + } if builder.config.cmd.only_modified() { cmd.arg("--only-modified"); } diff --git a/src/bootstrap/src/core/builder.rs b/src/bootstrap/src/core/builder.rs index ff0d1f3a725d2..5df962e939ed6 100644 --- a/src/bootstrap/src/core/builder.rs +++ b/src/bootstrap/src/core/builder.rs @@ -1614,6 +1614,10 @@ impl<'a> Builder<'a> { rustflags.arg("-Csymbol-mangling-version=legacy"); } + if self.config.rust_randomize_layout { + rustflags.arg("-Zrandomize-layout"); + } + // Enable compile-time checking of `cfg` names, values and Cargo `features`. // // Note: `std`, `alloc` and `core` imports some dependencies by #[path] (like diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs index bdfee55d8d183..547e338e049fc 100644 --- a/src/bootstrap/src/core/config/config.rs +++ b/src/bootstrap/src/core/config/config.rs @@ -280,6 +280,7 @@ pub struct Config { pub rust_codegen_backends: Vec, pub rust_verify_llvm_ir: bool, pub rust_thin_lto_import_instr_limit: Option, + pub rust_randomize_layout: bool, pub rust_remap_debuginfo: bool, pub rust_new_symbol_mangling: Option, pub rust_profile_use: Option, @@ -1088,6 +1089,7 @@ define_config! { codegen_units: Option = "codegen-units", codegen_units_std: Option = "codegen-units-std", debug_assertions: Option = "debug-assertions", + randomize_layout: Option = "randomize-layout", debug_assertions_std: Option = "debug-assertions-std", overflow_checks: Option = "overflow-checks", overflow_checks_std: Option = "overflow-checks-std", @@ -1179,6 +1181,7 @@ impl Config { backtrace: true, rust_optimize: RustOptimize::Bool(true), rust_optimize_tests: true, + rust_randomize_layout: false, submodules: None, docs: true, docs_minification: true, @@ -1629,6 +1632,7 @@ impl Config { backtrace, incremental, parallel_compiler, + randomize_layout, default_linker, channel, description, @@ -1718,6 +1722,7 @@ impl Config { set(&mut config.lld_mode, lld_mode); set(&mut config.llvm_bitcode_linker_enabled, llvm_bitcode_linker); + config.rust_randomize_layout = randomize_layout.unwrap_or_default(); config.llvm_tools_enabled = llvm_tools.unwrap_or(true); config.rustc_parallel = parallel_compiler.unwrap_or(config.channel == "dev" || config.channel == "nightly"); @@ -2889,6 +2894,7 @@ fn check_incompatible_options_for_ci_rustc( let Rust { // Following options are the CI rustc incompatible ones. optimize, + randomize_layout, debug_logging, debuginfo_level_rustc, llvm_tools, @@ -2953,6 +2959,7 @@ fn check_incompatible_options_for_ci_rustc( // otherwise, we just print a warning with `warn` macro. err!(current_rust_config.optimize, optimize); + err!(current_rust_config.randomize_layout, randomize_layout); err!(current_rust_config.debug_logging, debug_logging); err!(current_rust_config.debuginfo_level_rustc, debuginfo_level_rustc); err!(current_rust_config.rpath, rpath); diff --git a/src/tools/compiletest/src/command-list.rs b/src/tools/compiletest/src/command-list.rs index a559d6f81a240..865aa76ddb0c7 100644 --- a/src/tools/compiletest/src/command-list.rs +++ b/src/tools/compiletest/src/command-list.rs @@ -136,6 +136,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[ "min-llvm-version", "min-system-llvm-version", "needs-asm-support", + "needs-deterministic-layouts", "needs-dlltool", "needs-dynamic-linking", "needs-force-clang-based-tests", diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs index 5831f7c3cf283..773d795f75a72 100644 --- a/src/tools/compiletest/src/common.rs +++ b/src/tools/compiletest/src/common.rs @@ -274,6 +274,9 @@ pub struct Config { /// Flags to pass to the compiler when building for the target pub target_rustcflags: Vec, + /// Whether the compiler and stdlib has been built with randomized struct layouts + pub rust_randomized_layout: bool, + /// Whether tests should be optimized by default. Individual test-suites and test files may /// override this setting. pub optimize_tests: bool, diff --git a/src/tools/compiletest/src/header/needs.rs b/src/tools/compiletest/src/header/needs.rs index 72b1b9c6d480a..e903f60ceb37f 100644 --- a/src/tools/compiletest/src/header/needs.rs +++ b/src/tools/compiletest/src/header/needs.rs @@ -134,6 +134,11 @@ pub(super) fn handle_needs( condition: config.target_cfg().relocation_model == "pic", ignore_reason: "ignored on targets without PIC relocation model", }, + Need { + name: "needs-deterministic-layouts", + condition: !config.rust_randomized_layout, + ignore_reason: "ignored when randomizing layouts", + }, Need { name: "needs-wasmtime", condition: config.runner.as_ref().is_some_and(|r| r.contains("wasmtime")), diff --git a/src/tools/compiletest/src/lib.rs b/src/tools/compiletest/src/lib.rs index 7018362af5410..5402e69bc664e 100644 --- a/src/tools/compiletest/src/lib.rs +++ b/src/tools/compiletest/src/lib.rs @@ -99,6 +99,11 @@ pub fn parse_config(args: Vec) -> Config { ) .optmulti("", "host-rustcflags", "flags to pass to rustc for host", "FLAGS") .optmulti("", "target-rustcflags", "flags to pass to rustc for target", "FLAGS") + .optflag( + "", + "rust-randomized-layout", + "set this when rustc/stdlib were compiled with randomized layouts", + ) .optflag("", "optimize-tests", "run tests with optimizations enabled") .optflag("", "verbose", "run tests verbosely, showing all output") .optflag( @@ -286,6 +291,7 @@ pub fn parse_config(args: Vec) -> Config { host_rustcflags: matches.opt_strs("host-rustcflags"), target_rustcflags: matches.opt_strs("target-rustcflags"), optimize_tests: matches.opt_present("optimize-tests"), + rust_randomized_layout: matches.opt_present("rust-randomized-layout"), target, host: opt_str2(matches.opt_str("host")), cdb, From f3bc08adbd120a12571373b982b39049cbbed93f Mon Sep 17 00:00:00 2001 From: The 8472 Date: Fri, 2 Sep 2022 20:15:53 +0200 Subject: [PATCH 2/7] ignore/fix layout-sensitive tests --- tests/codegen/issues/issue-86106.rs | 1 + tests/codegen/mem-replace-big-type.rs | 1 + tests/codegen/slice-iter-nonnull.rs | 1 + tests/codegen/vecdeque-drain.rs | 1 + .../mir-opt/pre-codegen/issue_117368_print_invalid_constant.rs | 1 + tests/ui/stats/hir-stats.rs | 3 +++ tests/ui/structs-enums/type-sizes.rs | 1 + 7 files changed, 9 insertions(+) diff --git a/tests/codegen/issues/issue-86106.rs b/tests/codegen/issues/issue-86106.rs index e8164c5c38021..8d1ce116d26cc 100644 --- a/tests/codegen/issues/issue-86106.rs +++ b/tests/codegen/issues/issue-86106.rs @@ -1,5 +1,6 @@ //@ only-64bit llvm appears to use stores instead of memset on 32bit //@ compile-flags: -C opt-level=3 -Z merge-functions=disabled +//@ needs-deterministic-layouts // The below two functions ensure that both `String::new()` and `"".to_string()` // produce the identical code. diff --git a/tests/codegen/mem-replace-big-type.rs b/tests/codegen/mem-replace-big-type.rs index d5eadda4469f6..e62f1a953dfd0 100644 --- a/tests/codegen/mem-replace-big-type.rs +++ b/tests/codegen/mem-replace-big-type.rs @@ -5,6 +5,7 @@ //@ compile-flags: -C no-prepopulate-passes -Zinline-mir=no //@ ignore-debug: precondition checks in ptr::read make them a bad candidate for MIR inlining +//@ needs-deterministic-layouts #![crate_type = "lib"] diff --git a/tests/codegen/slice-iter-nonnull.rs b/tests/codegen/slice-iter-nonnull.rs index c960688b00c18..eda807d36822d 100644 --- a/tests/codegen/slice-iter-nonnull.rs +++ b/tests/codegen/slice-iter-nonnull.rs @@ -1,4 +1,5 @@ //@ compile-flags: -O +//@ needs-deterministic-layouts #![crate_type = "lib"] #![feature(exact_size_is_empty)] diff --git a/tests/codegen/vecdeque-drain.rs b/tests/codegen/vecdeque-drain.rs index 31fcf035f1154..fca1ed367e6fc 100644 --- a/tests/codegen/vecdeque-drain.rs +++ b/tests/codegen/vecdeque-drain.rs @@ -1,6 +1,7 @@ // Check that draining at the front or back doesn't copy memory. //@ compile-flags: -O +//@ needs-deterministic-layouts //@ ignore-debug: FIXME: checks for call detect scoped noalias metadata #![crate_type = "lib"] diff --git a/tests/mir-opt/pre-codegen/issue_117368_print_invalid_constant.rs b/tests/mir-opt/pre-codegen/issue_117368_print_invalid_constant.rs index c92424f298314..08347f71b4239 100644 --- a/tests/mir-opt/pre-codegen/issue_117368_print_invalid_constant.rs +++ b/tests/mir-opt/pre-codegen/issue_117368_print_invalid_constant.rs @@ -1,3 +1,4 @@ +//@needs-deterministic-layouts // Verify that we do not ICE when printing an invalid constant. // EMIT_MIR_FOR_EACH_BIT_WIDTH // EMIT_MIR_FOR_EACH_PANIC_STRATEGY diff --git a/tests/ui/stats/hir-stats.rs b/tests/ui/stats/hir-stats.rs index 249413d80e82a..7c5da8cf554b6 100644 --- a/tests/ui/stats/hir-stats.rs +++ b/tests/ui/stats/hir-stats.rs @@ -1,12 +1,15 @@ //@ check-pass //@ compile-flags: -Zhir-stats //@ only-x86_64 +// layout randomization affects the hir stat output +//@ needs-deterministic-layouts // Type layouts sometimes change. When that happens, until the next bootstrap // bump occurs, stage1 and stage2 will give different outputs for this test. // Add an `ignore-stage1` comment marker to work around that problem during // that time. + // The aim here is to include at least one of every different type of top-level // AST/HIR node reported by `-Zhir-stats`. diff --git a/tests/ui/structs-enums/type-sizes.rs b/tests/ui/structs-enums/type-sizes.rs index 9c933a9ef1c4f..5ca9c8678b790 100644 --- a/tests/ui/structs-enums/type-sizes.rs +++ b/tests/ui/structs-enums/type-sizes.rs @@ -1,4 +1,5 @@ //@ run-pass +//@ needs-deterministic-layouts #![allow(non_camel_case_types)] #![allow(dead_code)] From 5bf8eeb9f34a738ebf49328c08d40951374cce18 Mon Sep 17 00:00:00 2001 From: The 8472 Date: Fri, 2 Sep 2022 20:17:20 +0200 Subject: [PATCH 3/7] disable size asserts in the compiler when randomizing layouts --- Cargo.lock | 1 + compiler/rustc/Cargo.toml | 1 + compiler/rustc_driver_impl/Cargo.toml | 5 +++++ compiler/rustc_index/Cargo.toml | 1 + compiler/rustc_index/src/lib.rs | 11 +++++++++++ compiler/rustc_middle/Cargo.toml | 1 + compiler/rustc_middle/src/query/plumbing.rs | 1 + src/bootstrap/src/lib.rs | 3 +++ 8 files changed, 24 insertions(+) diff --git a/Cargo.lock b/Cargo.lock index 6ea4cd8f5aca4..ec3b95d0d98fa 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -3569,6 +3569,7 @@ dependencies = [ "rustc_hir_pretty", "rustc_hir_typeck", "rustc_incremental", + "rustc_index", "rustc_infer", "rustc_interface", "rustc_lint", diff --git a/compiler/rustc/Cargo.toml b/compiler/rustc/Cargo.toml index 5008069542f1f..a2fc9d5c408e3 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_driver_impl/Cargo.toml b/compiler/rustc_driver_impl/Cargo.toml index 91cbffcd7072b..6d6d3f35a4b1b 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 92ea3f278dc43..f7d18f84e3452 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 f773b5b46adae..52f354b8ecaff 100644 --- a/compiler/rustc_index/src/lib.rs +++ b/compiler/rustc_index/src/lib.rs @@ -33,8 +33,19 @@ pub use vec::IndexVec; /// /// #[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 69e3b703ccee1..b23589afb5874 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 c9bd702cce340..0320a91d142b7 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::>() > 64 { panic!("{}", concat!( diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs index 268392c5fb118..dc852e894a013 100644 --- a/src/bootstrap/src/lib.rs +++ b/src/bootstrap/src/lib.rs @@ -678,6 +678,9 @@ impl Build { if self.config.rustc_parallel { features.push("rustc_use_parallel_compiler"); } + if self.config.rust_randomize_layout { + features.push("rustc_randomized_layouts"); + } // If debug logging is on, then we want the default for tracing: // https://github.com/tokio-rs/tracing/blob/3dd5c03d907afdf2c39444a29931833335171554/tracing/src/level_filters.rs#L26 From e3169f76e6597bc3b582070436ce513b5db2dab8 Mon Sep 17 00:00:00 2001 From: The 8472 Date: Fri, 2 Sep 2022 20:18:19 +0200 Subject: [PATCH 4/7] when -Zrandomize-layout is enabled disable alloc test testing internal struct sizes --- library/alloc/Cargo.toml | 1 + library/alloc/src/collections/btree/node/tests.rs | 2 +- src/bootstrap/src/core/builder.rs | 3 +++ 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/library/alloc/Cargo.toml b/library/alloc/Cargo.toml index 4365bcc4ad022..1bd4434d4f7e9 100644 --- a/library/alloc/Cargo.toml +++ b/library/alloc/Cargo.toml @@ -52,4 +52,5 @@ check-cfg = [ 'cfg(no_global_oom_handling)', 'cfg(no_rc)', 'cfg(no_sync)', + 'cfg(randomized_layouts)', ] diff --git a/library/alloc/src/collections/btree/node/tests.rs b/library/alloc/src/collections/btree/node/tests.rs index d230749d71231..4d2fa0f094171 100644 --- a/library/alloc/src/collections/btree/node/tests.rs +++ b/library/alloc/src/collections/btree/node/tests.rs @@ -90,7 +90,7 @@ fn test_partial_eq() { #[test] #[cfg(target_arch = "x86_64")] -#[cfg_attr(miri, ignore)] // We'd like to run Miri with layout randomization +#[cfg_attr(any(miri, randomized_layouts), ignore)] // We'd like to run Miri with layout randomization fn test_sizes() { assert_eq!(core::mem::size_of::>(), 16); assert_eq!(core::mem::size_of::>(), 16 + CAPACITY * 2 * 8); diff --git a/src/bootstrap/src/core/builder.rs b/src/bootstrap/src/core/builder.rs index 5df962e939ed6..3043fd09ed19c 100644 --- a/src/bootstrap/src/core/builder.rs +++ b/src/bootstrap/src/core/builder.rs @@ -2193,6 +2193,9 @@ impl<'a> Builder<'a> { rustflags.arg("-Zvalidate-mir"); rustflags.arg(&format!("-Zmir-opt-level={mir_opt_level}")); } + if self.config.rust_randomize_layout { + rustflags.arg("--cfg=randomized_layouts"); + } // Always enable inlining MIR when building the standard library. // Without this flag, MIR inlining is disabled when incremental compilation is enabled. // That causes some mir-opt tests which inline functions from the standard library to From 1e377c5b9fd820d97d7fa3f0447c1c45b5fb64c7 Mon Sep 17 00:00:00 2001 From: The 8472 Date: Fri, 2 Sep 2022 22:44:39 +0200 Subject: [PATCH 5/7] enable layout randomization in x86_64-gnu-llvm-17 CI job --- src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile | 1 + 1 file changed, 1 insertion(+) diff --git a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile index 275acb47c33a7..3acc2ceb135ef 100644 --- a/src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile +++ b/src/ci/docker/host-x86_64/x86_64-gnu-llvm-17/Dockerfile @@ -50,6 +50,7 @@ ENV RUST_CONFIGURE_ARGS \ --build=x86_64-unknown-linux-gnu \ --llvm-root=/usr/lib/llvm-17 \ --enable-llvm-link-shared \ + --set rust.randomize-layout=true \ --set rust.thin-lto-import-instr-limit=10 COPY host-x86_64/dist-x86_64-linux/shared.sh /scripts/ From df20808f4dc7828c0f78cd17c3bd9edbd499d6f3 Mon Sep 17 00:00:00 2001 From: The 8472 Date: Sat, 31 Aug 2024 14:43:23 +0200 Subject: [PATCH 6/7] inhibit layout randomization for Box --- compiler/rustc_abi/src/layout.rs | 11 +++++++---- compiler/rustc_abi/src/lib.rs | 15 +++++++++++---- compiler/rustc_middle/src/ty/mod.rs | 10 +++++++++- 3 files changed, 27 insertions(+), 9 deletions(-) diff --git a/compiler/rustc_abi/src/layout.rs b/compiler/rustc_abi/src/layout.rs index 5160b4ed0a2ac..7432768be4a58 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 = 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 df29b3d54f0fb..be42bc8493243 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()`. 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_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs index e41ea7507efff..874e75f717905 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); } From c218c754568351e44a8c8f07702c090c6c2ae945 Mon Sep 17 00:00:00 2001 From: The 8472 Date: Sat, 31 Aug 2024 18:02:01 +0200 Subject: [PATCH 7/7] exclude tools with deps that have size asserts --- src/bootstrap/src/core/builder.rs | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/bootstrap/src/core/builder.rs b/src/bootstrap/src/core/builder.rs index 3043fd09ed19c..a4474046fb8ab 100644 --- a/src/bootstrap/src/core/builder.rs +++ b/src/bootstrap/src/core/builder.rs @@ -1614,7 +1614,12 @@ impl<'a> Builder<'a> { rustflags.arg("-Csymbol-mangling-version=legacy"); } - if self.config.rust_randomize_layout { + // FIXME: the following components don't build with `-Zrandomize-layout` yet: + // - wasm-component-ld, due to the `wast`crate + // - rust-analyzer, due to the rowan crate + // so we exclude entire categories of steps here due to lack of fine-grained control over + // rustflags. + if self.config.rust_randomize_layout && mode != Mode::ToolStd && mode != Mode::ToolRustc { rustflags.arg("-Zrandomize-layout"); }