From 3519ad59ae70e657b7f0175254705e282f8b2df4 Mon Sep 17 00:00:00 2001 From: Jakub Chlanda Date: Fri, 10 Jul 2026 12:01:47 +0000 Subject: [PATCH 1/5] [PAC] Include discriminator in `FnAbi`, add `llvm.ptrauth.resign` This patch introduces the following: * Extends `FnAbi` (`callconv`) with a `ptrauth_type_discriminator` field. This field is only used when emitting pointer authentication call bundles. It is stored in `FnAbi` because the call site is not guaranteed to have access to an `Instance`, so the discriminator cannot always be computed on demand. * Adds support for `llvm.ptrauth.resign`. This intrinsic will be used when support for semantic transmute is added. * Performs a minor API redesign as groundwork for allowing call sites to modify schemas in place. --- compiler/rustc_codegen_gcc/src/builder.rs | 11 +++++++ compiler/rustc_codegen_gcc/src/common.rs | 2 +- compiler/rustc_codegen_gcc/src/context.rs | 2 +- compiler/rustc_codegen_gcc/src/int.rs | 1 + compiler/rustc_codegen_llvm/src/builder.rs | 32 +++++++++++++++++-- compiler/rustc_codegen_llvm/src/common.rs | 23 +++++++------ compiler/rustc_codegen_llvm/src/context.rs | 4 +-- .../rustc_codegen_ssa/src/traits/builder.rs | 9 ++++++ .../rustc_codegen_ssa/src/traits/consts.rs | 2 +- compiler/rustc_codegen_ssa/src/traits/misc.rs | 2 +- compiler/rustc_session/src/session.rs | 25 ++++++++++++--- compiler/rustc_target/src/callconv/mod.rs | 8 +++-- compiler/rustc_ty_utils/src/abi.rs | 6 ++++ tests/ui/abi/c-zst.aarch64-darwin.stderr | 1 + tests/ui/abi/c-zst.powerpc-linux.stderr | 1 + tests/ui/abi/c-zst.s390x-linux.stderr | 1 + tests/ui/abi/c-zst.sparc64-linux.stderr | 1 + tests/ui/abi/c-zst.x86_64-linux.stderr | 1 + .../ui/abi/c-zst.x86_64-pc-windows-gnu.stderr | 1 + tests/ui/abi/debug.generic.stderr | 12 +++++++ tests/ui/abi/debug.loongarch64.stderr | 12 +++++++ tests/ui/abi/debug.riscv64.stderr | 12 +++++++ .../x86-64-sysv64-arg-ext.apple.stderr | 6 ++++ .../x86-64-sysv64-arg-ext.other.stderr | 6 ++++ tests/ui/abi/pass-indirectly-attr.stderr | 2 ++ tests/ui/abi/sysv64-zst.stderr | 1 + .../pass-by-value-abi.aarch64.stderr | 1 + .../c-variadic/pass-by-value-abi.win.stderr | 1 + .../pass-by-value-abi.x86_64.stderr | 3 ++ 29 files changed, 165 insertions(+), 24 deletions(-) diff --git a/compiler/rustc_codegen_gcc/src/builder.rs b/compiler/rustc_codegen_gcc/src/builder.rs index 88049d67964b1..d42438ba92f59 100644 --- a/compiler/rustc_codegen_gcc/src/builder.rs +++ b/compiler/rustc_codegen_gcc/src/builder.rs @@ -1850,6 +1850,17 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> { fn fptosi_sat(&mut self, val: RValue<'gcc>, dest_ty: Type<'gcc>) -> RValue<'gcc> { self.fptoint_sat(true, val, dest_ty) } + + fn ptrauth_resign( + &mut self, + _value: Self::Value, + _old_key: u32, + _old_discriminator: u64, + _new_key: u32, + _new_discriminator: u64, + ) -> Self::Value { + bug!("Resigning of pointers not implemented"); + } } impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> { diff --git a/compiler/rustc_codegen_gcc/src/common.rs b/compiler/rustc_codegen_gcc/src/common.rs index 6bd186f1121fc..712a1c14ef8e6 100644 --- a/compiler/rustc_codegen_gcc/src/common.rs +++ b/compiler/rustc_codegen_gcc/src/common.rs @@ -323,7 +323,7 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> { cv: Scalar, layout: abi::Scalar, ty: Type<'gcc>, - _schema: Option<&PointerAuthSchema>, + _ptrauth_schema: Option, ) -> RValue<'gcc> { let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() }; match cv { diff --git a/compiler/rustc_codegen_gcc/src/context.rs b/compiler/rustc_codegen_gcc/src/context.rs index 19fbe37c27b9e..8c1fc18ee7a78 100644 --- a/compiler/rustc_codegen_gcc/src/context.rs +++ b/compiler/rustc_codegen_gcc/src/context.rs @@ -405,7 +405,7 @@ impl<'gcc, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> { fn get_fn_addr( &self, instance: Instance<'tcx>, - _pointer_auth_schema: Option<&PointerAuthSchema>, + _ptrauth_schema: Option, ) -> RValue<'gcc> { let func_name = self.tcx.symbol_name(instance).name; diff --git a/compiler/rustc_codegen_gcc/src/int.rs b/compiler/rustc_codegen_gcc/src/int.rs index dfae4eceebe44..10cbe1ccb8059 100644 --- a/compiler/rustc_codegen_gcc/src/int.rs +++ b/compiler/rustc_codegen_gcc/src/int.rs @@ -375,6 +375,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> { fixed_count: 3, conv: CanonAbi::C, can_unwind: false, + ptrauth_discriminator: 0, }; fn_abi.adjust_for_foreign_abi(self.cx, ExternAbi::C { unwind: false }); diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs index 87c941cdeb23a..63e6faf3ced93 100644 --- a/compiler/rustc_codegen_llvm/src/builder.rs +++ b/compiler/rustc_codegen_llvm/src/builder.rs @@ -1553,6 +1553,30 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> { let cold_inline = llvm::AttributeKind::Cold.create_attr(self.llcx); attributes::apply_to_callsite(llret, llvm::AttributePlace::Function, &[cold_inline]); } + + fn ptrauth_resign( + &mut self, + value: &'ll Value, + old_key: u32, + old_discriminator: u64, + new_key: u32, + new_discriminator: u64, + ) -> &'ll Value { + let ptr_as_int = self.ptrtoint(value, self.type_i64()); + let resigned_int = self.call_intrinsic( + "llvm.ptrauth.resign", + &[], + &[ + ptr_as_int, + self.const_i32(old_key as i32), + self.const_i64(old_discriminator as i64), + self.const_i32(new_key as i32), + self.const_i64(new_discriminator as i64), + ], + ); + + self.inttoptr(resigned_int, self.val_ty(value)) + } } impl<'ll> StaticBuilderMethods for Builder<'_, 'll, '_> { @@ -2171,8 +2195,12 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> { // bundles. // Once this is resolved, we should analyze each call and skip direct calls. See the // discussion in the rust-lang issue: - let key: u32 = 0; - let discriminator: u64 = 0; + + let key: u32 = self.sess().pointer_authentication_fn_ptr_key().unwrap() as u32; + // If sess().pointer_authentication_fn_ptr_type_discrimination() is true, this contains + // the function pointer type discriminator; otherwise, it is 0. + let discriminator = fn_abi?.ptrauth_discriminator; + Some(llvm::OperandBundleBox::new( "ptrauth", &[self.const_u32(key), self.const_u64(discriminator)], diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs index 3fe4550b6759e..8f63e409028ce 100644 --- a/compiler/rustc_codegen_llvm/src/common.rs +++ b/compiler/rustc_codegen_llvm/src/common.rs @@ -30,11 +30,9 @@ pub(crate) fn maybe_sign_fn_ptr<'ll, 'tcx>( cx: &CodegenCx<'ll, '_>, instance: Instance<'tcx>, llfn: &'ll llvm::Value, - schema: &PointerAuthSchema, + ptrauth_schema: PointerAuthSchema, ) -> &'ll llvm::Value { - if cx.tcx.sess.pointer_authentication_functions().is_none() { - return llfn; - } + assert!(cx.tcx.sess.pointer_authentication_functions().is_some()); // Only free functions or methods let def_id = instance.def_id(); @@ -54,7 +52,7 @@ pub(crate) fn maybe_sign_fn_ptr<'ll, 'tcx>( return llfn; } - let addr_diversity = match schema.is_address_discriminated { + let addr_diversity = match ptrauth_schema.is_address_discriminated { PointerAuthAddressDiscriminator::HardwareAddress(true) => Some(llfn), PointerAuthAddressDiscriminator::HardwareAddress(false) => None, PointerAuthAddressDiscriminator::Synthetic(val) => { @@ -63,7 +61,12 @@ pub(crate) fn maybe_sign_fn_ptr<'ll, 'tcx>( Some(unsafe { llvm::LLVMConstIntToPtr(llval, llty) }) } }; - const_ptr_auth(llfn, schema.key as u32, schema.constant_discriminator as u64, addr_diversity) + const_ptr_auth( + llfn, + ptrauth_schema.key as u32, + ptrauth_schema.constant_discriminator as u64, + addr_diversity, + ) } /* @@ -179,11 +182,11 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> { &self, global_alloc: GlobalAlloc<'tcx>, need_symbol_name: bool, - schema: Option<&PointerAuthSchema>, + ptrauth_schema: Option, ) -> Result<&'ll Value, u64> { let alloc = match global_alloc { GlobalAlloc::Function { instance, .. } => { - return Ok(self.get_fn_addr(instance, schema)); + return Ok(self.get_fn_addr(instance, ptrauth_schema)); } GlobalAlloc::Static(def_id) => { assert!(self.tcx.is_static(def_id)); @@ -405,7 +408,7 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> { cv: Scalar, layout: abi::Scalar, llty: &'ll Type, - schema: Option<&PointerAuthSchema>, + ptrauth_schema: Option, ) -> &'ll Value { let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() }; match cv { @@ -422,7 +425,7 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> { let (prov, offset) = ptr.prov_and_relative_offset(); let global_alloc = self.tcx.global_alloc(prov.alloc_id()); let base_addr_space = global_alloc.address_space(self); - let base_addr = match self.alloc_to_backend(global_alloc, false, schema) { + let base_addr = match self.alloc_to_backend(global_alloc, false, ptrauth_schema) { Ok(base_addr) => base_addr, Err(base_addr) => { let val = base_addr.wrapping_add(offset.bytes()); diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs index 853c4bfc9ca3f..c136fb6bbde8a 100644 --- a/compiler/rustc_codegen_llvm/src/context.rs +++ b/compiler/rustc_codegen_llvm/src/context.rs @@ -938,7 +938,7 @@ impl<'ll, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> { fn get_fn_addr( &self, instance: Instance<'tcx>, - pointer_auth_schema: Option<&PointerAuthSchema>, + ptrauth_schema: Option, ) -> &'ll Value { // When pointer authentication metadata is provided, `get_fn_addr` will // attempt to sign the pointer using LLVM's `ConstPtrAuth` constant @@ -953,7 +953,7 @@ impl<'ll, 'tcx> MiscCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> { // , and comment in // builder's `ptrauth_operand_bundle`. let llfn = get_fn(self, instance); - match pointer_auth_schema { + match ptrauth_schema { Some(schema) => common::maybe_sign_fn_ptr(self, instance, llfn, schema), None => llfn, } diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs index cb0209a0ae369..0e37705ec82b5 100644 --- a/compiler/rustc_codegen_ssa/src/traits/builder.rs +++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs @@ -667,4 +667,13 @@ pub trait BuilderMethods<'a, 'tcx>: fn zext(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value; fn apply_attrs_to_cleanup_callsite(&mut self, llret: Self::Value); + + fn ptrauth_resign( + &mut self, + value: Self::Value, + old_key: u32, + old_discriminator: u64, + new_key: u32, + new_discriminator: u64, + ) -> Self::Value; } diff --git a/compiler/rustc_codegen_ssa/src/traits/consts.rs b/compiler/rustc_codegen_ssa/src/traits/consts.rs index b4eba38d39c19..b45b5667be6c9 100644 --- a/compiler/rustc_codegen_ssa/src/traits/consts.rs +++ b/compiler/rustc_codegen_ssa/src/traits/consts.rs @@ -47,7 +47,7 @@ pub trait ConstCodegenMethods: BackendTypes { cv: Scalar, layout: abi::Scalar, llty: Self::Type, - schema: Option<&PointerAuthSchema>, + ptrauth_schema: Option, ) -> Self::Value; fn const_ptr_byte_offset(&self, val: Self::Value, offset: abi::Size) -> Self::Value; diff --git a/compiler/rustc_codegen_ssa/src/traits/misc.rs b/compiler/rustc_codegen_ssa/src/traits/misc.rs index add7128a2974b..3d1a931a12e83 100644 --- a/compiler/rustc_codegen_ssa/src/traits/misc.rs +++ b/compiler/rustc_codegen_ssa/src/traits/misc.rs @@ -22,7 +22,7 @@ pub trait MiscCodegenMethods<'tcx>: BackendTypes { fn get_fn_addr( &self, instance: Instance<'tcx>, - pointer_auth_schema: Option<&PointerAuthSchema>, + ptrauth_schema: Option, ) -> Self::Value; fn eh_personality(&self) -> Self::Function; fn sess(&self) -> &Session; diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs index f04f40dd17168..e31176a88acee 100644 --- a/compiler/rustc_session/src/session.rs +++ b/compiler/rustc_session/src/session.rs @@ -95,6 +95,7 @@ pub enum PointerAuthARM8_3Key { } /// Forms of extra discrimination. +#[derive(Clone, Debug, PartialEq)] pub enum PointerAuthDiscrimination { /// No additional discrimination. None, @@ -107,6 +108,7 @@ pub enum PointerAuthDiscrimination { } /// Types of address discrimination. +#[derive(Clone, Debug)] pub enum PointerAuthAddressDiscriminator { /// Enable/disable hardware address discrimination. HardwareAddress(bool), @@ -115,6 +117,7 @@ pub enum PointerAuthAddressDiscriminator { Synthetic(u64), } +#[derive(Clone, Debug)] pub struct PointerAuthSchema { pub is_address_discriminated: PointerAuthAddressDiscriminator, pub discrimination_kind: PointerAuthDiscrimination, @@ -1185,12 +1188,26 @@ impl Session { self.pointer_auth_config.is_some() } - pub fn pointer_authentication_functions(&self) -> Option<&PointerAuthSchema> { - self.pointer_auth_config.as_ref().and_then(|cfg| cfg.function_pointers.as_ref()) + pub fn pointer_authentication_functions(&self) -> Option { + self.pointer_auth_config.as_ref().and_then(|cfg| cfg.function_pointers.clone()) } - pub fn pointer_authentication_init_fini(&self) -> Option<&PointerAuthSchema> { - self.pointer_auth_config.as_ref().and_then(|cfg| cfg.init_fini.as_ref()) + pub fn pointer_authentication_init_fini(&self) -> Option { + self.pointer_auth_config.as_ref().and_then(|cfg| cfg.init_fini.clone()) + } + + pub fn pointer_authentication_fn_ptr_type_discrimination(&self) -> bool { + self.pointer_auth_config + .as_ref() + .and_then(|cfg| cfg.function_pointers.as_ref()) + .is_some_and(|schema| schema.discrimination_kind == PointerAuthDiscrimination::Type) + } + + pub fn pointer_authentication_fn_ptr_key(&self) -> Option { + self.pointer_auth_config + .as_ref() + .and_then(|cfg| cfg.function_pointers.as_ref()) + .map(|schema| schema.key) } } diff --git a/compiler/rustc_target/src/callconv/mod.rs b/compiler/rustc_target/src/callconv/mod.rs index 26fedbd8a5481..83f38b5be8a9b 100644 --- a/compiler/rustc_target/src/callconv/mod.rs +++ b/compiler/rustc_target/src/callconv/mod.rs @@ -625,12 +625,15 @@ pub struct FnAbi<'a, Ty> { pub conv: CanonAbi, /// Indicates if an unwind may happen across a call to this function. pub can_unwind: bool, + /// Computed type discriminator for pointer authentication purpose. + pub ptrauth_discriminator: u64, } // Needs to be a custom impl because of the bounds on the `TyAndLayout` debug impl. impl<'a, Ty: fmt::Display> fmt::Debug for FnAbi<'a, Ty> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - let FnAbi { args, ret, c_variadic, fixed_count, conv, can_unwind } = self; + let FnAbi { args, ret, c_variadic, fixed_count, conv, can_unwind, ptrauth_discriminator } = + self; f.debug_struct("FnAbi") .field("args", args) .field("ret", ret) @@ -638,6 +641,7 @@ impl<'a, Ty: fmt::Display> fmt::Debug for FnAbi<'a, Ty> { .field("fixed_count", fixed_count) .field("conv", conv) .field("can_unwind", can_unwind) + .field("ptrauth_discriminator", ptrauth_discriminator) .finish() } } @@ -950,6 +954,6 @@ mod size_asserts { use super::*; // tidy-alphabetical-start static_assert_size!(ArgAbi<'_, usize>, 56); - static_assert_size!(FnAbi<'_, usize>, 80); + static_assert_size!(FnAbi<'_, usize>, 88); // tidy-alphabetical-end } diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs index 65d589cc35aa0..2b59c905b19f5 100644 --- a/compiler/rustc_ty_utils/src/abi.rs +++ b/compiler/rustc_ty_utils/src/abi.rs @@ -6,6 +6,7 @@ use rustc_hir::attrs::lang_items::LangItem; use rustc_hir::{self as hir, find_attr}; use rustc_middle::bug; use rustc_middle::middle::deduced_param_attrs::DeducedParamAttrs; +use rustc_middle::ptrauth::ptrauth_compute_fn_ptr_type_discriminator_for; use rustc_middle::query::Providers; use rustc_middle::ty::layout::{ FnAbiError, HasTyCtxt, HasTypingEnv, LayoutCx, LayoutOf, TyAndLayout, fn_can_unwind, @@ -611,6 +612,11 @@ fn fn_abi_new_uncached<'tcx>( determined_fn_def_id, sig.abi(), ), + ptrauth_discriminator: if tcx.sess.pointer_authentication_fn_ptr_type_discrimination() { + ptrauth_compute_fn_ptr_type_discriminator_for(tcx, sig).unwrap_or(0).into() + } else { + 0 + }, }; fn_abi_adjust_for_abi(cx, &mut fn_abi, sig.abi()); debug!("fn_abi_new_uncached = {:?}", fn_abi); diff --git a/tests/ui/abi/c-zst.aarch64-darwin.stderr b/tests/ui/abi/c-zst.aarch64-darwin.stderr index 6d2ac90c0c975..a99eb7cd1e830 100644 --- a/tests/ui/abi/c-zst.aarch64-darwin.stderr +++ b/tests/ui/abi/c-zst.aarch64-darwin.stderr @@ -59,6 +59,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.powerpc-linux.stderr b/tests/ui/abi/c-zst.powerpc-linux.stderr index edea2d5772280..308d3a8625638 100644 --- a/tests/ui/abi/c-zst.powerpc-linux.stderr +++ b/tests/ui/abi/c-zst.powerpc-linux.stderr @@ -70,6 +70,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.s390x-linux.stderr b/tests/ui/abi/c-zst.s390x-linux.stderr index edea2d5772280..308d3a8625638 100644 --- a/tests/ui/abi/c-zst.s390x-linux.stderr +++ b/tests/ui/abi/c-zst.s390x-linux.stderr @@ -70,6 +70,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.sparc64-linux.stderr b/tests/ui/abi/c-zst.sparc64-linux.stderr index edea2d5772280..308d3a8625638 100644 --- a/tests/ui/abi/c-zst.sparc64-linux.stderr +++ b/tests/ui/abi/c-zst.sparc64-linux.stderr @@ -70,6 +70,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.x86_64-linux.stderr b/tests/ui/abi/c-zst.x86_64-linux.stderr index 6d2ac90c0c975..a99eb7cd1e830 100644 --- a/tests/ui/abi/c-zst.x86_64-linux.stderr +++ b/tests/ui/abi/c-zst.x86_64-linux.stderr @@ -59,6 +59,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.x86_64-pc-windows-gnu.stderr b/tests/ui/abi/c-zst.x86_64-pc-windows-gnu.stderr index edea2d5772280..308d3a8625638 100644 --- a/tests/ui/abi/c-zst.x86_64-pc-windows-gnu.stderr +++ b/tests/ui/abi/c-zst.x86_64-pc-windows-gnu.stderr @@ -70,6 +70,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/debug.generic.stderr b/tests/ui/abi/debug.generic.stderr index 6242d93b09534..ae0edfd7369a2 100644 --- a/tests/ui/abi/debug.generic.stderr +++ b/tests/ui/abi/debug.generic.stderr @@ -106,6 +106,7 @@ error: fn_abi_of(test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:31:1 | @@ -187,6 +188,7 @@ error: fn_abi_of(TestFnPtr) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:37:1 | @@ -258,6 +260,7 @@ error: fn_abi_of(test_generic) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:40:1 | @@ -336,6 +339,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -402,6 +406,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:59:1 | @@ -481,6 +486,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -554,6 +560,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:62:1 | @@ -626,6 +633,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -692,6 +700,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:65:1 | @@ -764,6 +773,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -830,6 +840,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:69:1 | @@ -924,6 +935,7 @@ error: fn_abi_of(assoc_test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:52:5 | diff --git a/tests/ui/abi/debug.loongarch64.stderr b/tests/ui/abi/debug.loongarch64.stderr index 176c68ecd4c7b..ed20ec1ef3283 100644 --- a/tests/ui/abi/debug.loongarch64.stderr +++ b/tests/ui/abi/debug.loongarch64.stderr @@ -106,6 +106,7 @@ error: fn_abi_of(test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:31:1 | @@ -187,6 +188,7 @@ error: fn_abi_of(TestFnPtr) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:37:1 | @@ -258,6 +260,7 @@ error: fn_abi_of(test_generic) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:40:1 | @@ -336,6 +339,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -402,6 +406,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:59:1 | @@ -481,6 +486,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -554,6 +560,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:62:1 | @@ -626,6 +633,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -692,6 +700,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:65:1 | @@ -764,6 +773,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -830,6 +840,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:69:1 | @@ -924,6 +935,7 @@ error: fn_abi_of(assoc_test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:52:5 | diff --git a/tests/ui/abi/debug.riscv64.stderr b/tests/ui/abi/debug.riscv64.stderr index 176c68ecd4c7b..ed20ec1ef3283 100644 --- a/tests/ui/abi/debug.riscv64.stderr +++ b/tests/ui/abi/debug.riscv64.stderr @@ -106,6 +106,7 @@ error: fn_abi_of(test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:31:1 | @@ -187,6 +188,7 @@ error: fn_abi_of(TestFnPtr) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:37:1 | @@ -258,6 +260,7 @@ error: fn_abi_of(test_generic) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:40:1 | @@ -336,6 +339,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -402,6 +406,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:59:1 | @@ -481,6 +486,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -554,6 +560,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:62:1 | @@ -626,6 +633,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -692,6 +700,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:65:1 | @@ -764,6 +773,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } right ABI = FnAbi { args: [ @@ -830,6 +840,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:69:1 | @@ -924,6 +935,7 @@ error: fn_abi_of(assoc_test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, + ptrauth_discriminator: 0, } --> $DIR/debug.rs:52:5 | diff --git a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr index 65818feab4297..927594534d9b8 100644 --- a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr +++ b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr @@ -69,6 +69,7 @@ error: fn_abi_of(i8) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:13:1 | @@ -146,6 +147,7 @@ error: fn_abi_of(u8) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:19:1 | @@ -223,6 +225,7 @@ error: fn_abi_of(i16) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:25:1 | @@ -300,6 +303,7 @@ error: fn_abi_of(u16) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:31:1 | @@ -377,6 +381,7 @@ error: fn_abi_of(i32) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:37:1 | @@ -454,6 +459,7 @@ error: fn_abi_of(u32) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:43:1 | diff --git a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr index cbe389c42d40a..113ad20e16bc4 100644 --- a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr +++ b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr @@ -69,6 +69,7 @@ error: fn_abi_of(i8) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:13:1 | @@ -146,6 +147,7 @@ error: fn_abi_of(u8) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:19:1 | @@ -223,6 +225,7 @@ error: fn_abi_of(i16) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:25:1 | @@ -300,6 +303,7 @@ error: fn_abi_of(u16) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:31:1 | @@ -377,6 +381,7 @@ error: fn_abi_of(i32) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:37:1 | @@ -454,6 +459,7 @@ error: fn_abi_of(u32) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/x86-64-sysv64-arg-ext.rs:43:1 | diff --git a/tests/ui/abi/pass-indirectly-attr.stderr b/tests/ui/abi/pass-indirectly-attr.stderr index efeec0d86982b..e03828c2e78a4 100644 --- a/tests/ui/abi/pass-indirectly-attr.stderr +++ b/tests/ui/abi/pass-indirectly-attr.stderr @@ -83,6 +83,7 @@ error: fn_abi_of(extern_c) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/pass-indirectly-attr.rs:20:1 | @@ -174,6 +175,7 @@ error: fn_abi_of(extern_rust) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/pass-indirectly-attr.rs:27:1 | diff --git a/tests/ui/abi/sysv64-zst.stderr b/tests/ui/abi/sysv64-zst.stderr index 82d3793c35328..ed8fe5b83fe7c 100644 --- a/tests/ui/abi/sysv64-zst.stderr +++ b/tests/ui/abi/sysv64-zst.stderr @@ -61,6 +61,7 @@ error: fn_abi_of(pass_zst) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/sysv64-zst.rs:8:1 | diff --git a/tests/ui/c-variadic/pass-by-value-abi.aarch64.stderr b/tests/ui/c-variadic/pass-by-value-abi.aarch64.stderr index 45edd7bc0e0ee..7f25ffc3c4481 100644 --- a/tests/ui/c-variadic/pass-by-value-abi.aarch64.stderr +++ b/tests/ui/c-variadic/pass-by-value-abi.aarch64.stderr @@ -70,6 +70,7 @@ error: fn_abi_of(take_va_list) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/pass-by-value-abi.rs:27:1 | diff --git a/tests/ui/c-variadic/pass-by-value-abi.win.stderr b/tests/ui/c-variadic/pass-by-value-abi.win.stderr index d5da912a9b89a..150a9262b0f88 100644 --- a/tests/ui/c-variadic/pass-by-value-abi.win.stderr +++ b/tests/ui/c-variadic/pass-by-value-abi.win.stderr @@ -66,6 +66,7 @@ error: fn_abi_of(take_va_list) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/pass-by-value-abi.rs:27:1 | diff --git a/tests/ui/c-variadic/pass-by-value-abi.x86_64.stderr b/tests/ui/c-variadic/pass-by-value-abi.x86_64.stderr index 1e203b93e66b3..1705d3ca7509b 100644 --- a/tests/ui/c-variadic/pass-by-value-abi.x86_64.stderr +++ b/tests/ui/c-variadic/pass-by-value-abi.x86_64.stderr @@ -70,6 +70,7 @@ error: fn_abi_of(take_va_list) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/pass-by-value-abi.rs:27:1 | @@ -150,6 +151,7 @@ error: fn_abi_of(take_va_list_sysv64) = FnAbi { SysV64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/pass-by-value-abi.rs:37:1 | @@ -230,6 +232,7 @@ error: fn_abi_of(take_va_list_win64) = FnAbi { Win64, ), can_unwind: false, + ptrauth_discriminator: 0, } --> $DIR/pass-by-value-abi.rs:44:1 | From 1846500cbc24252a6678ba48452086707c9a0599 Mon Sep 17 00:00:00 2001 From: Jakub Chlanda Date: Thu, 20 Aug 2026 06:47:34 +0000 Subject: [PATCH 2/5] [PAC] Use Option in FnAbi's discriminator field --- compiler/rustc_codegen_gcc/src/int.rs | 2 +- compiler/rustc_codegen_llvm/src/builder.rs | 7 +++--- compiler/rustc_target/src/callconv/mod.rs | 4 ++-- compiler/rustc_ty_utils/src/abi.rs | 4 ++-- tests/ui/abi/c-zst.aarch64-darwin.stderr | 2 +- tests/ui/abi/c-zst.powerpc-linux.stderr | 2 +- tests/ui/abi/c-zst.s390x-linux.stderr | 2 +- tests/ui/abi/c-zst.sparc64-linux.stderr | 2 +- tests/ui/abi/c-zst.x86_64-linux.stderr | 2 +- .../ui/abi/c-zst.x86_64-pc-windows-gnu.stderr | 2 +- tests/ui/abi/debug.generic.stderr | 24 +++++++++---------- tests/ui/abi/debug.loongarch64.stderr | 24 +++++++++---------- tests/ui/abi/debug.riscv64.stderr | 24 +++++++++---------- .../x86-64-sysv64-arg-ext.apple.stderr | 12 +++++----- .../x86-64-sysv64-arg-ext.other.stderr | 12 +++++----- tests/ui/abi/pass-indirectly-attr.stderr | 4 ++-- tests/ui/abi/sysv64-zst.stderr | 2 +- .../pass-by-value-abi.aarch64.stderr | 2 +- .../c-variadic/pass-by-value-abi.win.stderr | 2 +- .../pass-by-value-abi.x86_64.stderr | 6 ++--- 20 files changed, 71 insertions(+), 70 deletions(-) diff --git a/compiler/rustc_codegen_gcc/src/int.rs b/compiler/rustc_codegen_gcc/src/int.rs index 10cbe1ccb8059..fe0654c665c76 100644 --- a/compiler/rustc_codegen_gcc/src/int.rs +++ b/compiler/rustc_codegen_gcc/src/int.rs @@ -375,7 +375,7 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> { fixed_count: 3, conv: CanonAbi::C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, }; fn_abi.adjust_for_foreign_abi(self.cx, ExternAbi::C { unwind: false }); diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs index 63e6faf3ced93..63563bad966d9 100644 --- a/compiler/rustc_codegen_llvm/src/builder.rs +++ b/compiler/rustc_codegen_llvm/src/builder.rs @@ -2197,9 +2197,10 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> { // discussion in the rust-lang issue: let key: u32 = self.sess().pointer_authentication_fn_ptr_key().unwrap() as u32; - // If sess().pointer_authentication_fn_ptr_type_discrimination() is true, this contains - // the function pointer type discriminator; otherwise, it is 0. - let discriminator = fn_abi?.ptrauth_discriminator; + // If sess().pointer_authentication_fn_ptr_type_discrimination() is enabled, this contains + // the function pointer type discriminator; otherwise, it is None. LLVM expects a u64 here, + // so use 0 when no discriminator is present. + let discriminator = fn_abi?.ptrauth_discriminator.unwrap_or(0); Some(llvm::OperandBundleBox::new( "ptrauth", diff --git a/compiler/rustc_target/src/callconv/mod.rs b/compiler/rustc_target/src/callconv/mod.rs index 83f38b5be8a9b..14ad0eb477d5d 100644 --- a/compiler/rustc_target/src/callconv/mod.rs +++ b/compiler/rustc_target/src/callconv/mod.rs @@ -626,7 +626,7 @@ pub struct FnAbi<'a, Ty> { /// Indicates if an unwind may happen across a call to this function. pub can_unwind: bool, /// Computed type discriminator for pointer authentication purpose. - pub ptrauth_discriminator: u64, + pub ptrauth_discriminator: Option, } // Needs to be a custom impl because of the bounds on the `TyAndLayout` debug impl. @@ -954,6 +954,6 @@ mod size_asserts { use super::*; // tidy-alphabetical-start static_assert_size!(ArgAbi<'_, usize>, 56); - static_assert_size!(FnAbi<'_, usize>, 88); + static_assert_size!(FnAbi<'_, usize>, 96); // tidy-alphabetical-end } diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs index 2b59c905b19f5..318b3273219a5 100644 --- a/compiler/rustc_ty_utils/src/abi.rs +++ b/compiler/rustc_ty_utils/src/abi.rs @@ -613,9 +613,9 @@ fn fn_abi_new_uncached<'tcx>( sig.abi(), ), ptrauth_discriminator: if tcx.sess.pointer_authentication_fn_ptr_type_discrimination() { - ptrauth_compute_fn_ptr_type_discriminator_for(tcx, sig).unwrap_or(0).into() + Some(ptrauth_compute_fn_ptr_type_discriminator_for(tcx, sig).unwrap_or(0).into()) } else { - 0 + None }, }; fn_abi_adjust_for_abi(cx, &mut fn_abi, sig.abi()); diff --git a/tests/ui/abi/c-zst.aarch64-darwin.stderr b/tests/ui/abi/c-zst.aarch64-darwin.stderr index a99eb7cd1e830..e7cb6199ab45c 100644 --- a/tests/ui/abi/c-zst.aarch64-darwin.stderr +++ b/tests/ui/abi/c-zst.aarch64-darwin.stderr @@ -59,7 +59,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.powerpc-linux.stderr b/tests/ui/abi/c-zst.powerpc-linux.stderr index 308d3a8625638..437ebd63ceba5 100644 --- a/tests/ui/abi/c-zst.powerpc-linux.stderr +++ b/tests/ui/abi/c-zst.powerpc-linux.stderr @@ -70,7 +70,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.s390x-linux.stderr b/tests/ui/abi/c-zst.s390x-linux.stderr index 308d3a8625638..437ebd63ceba5 100644 --- a/tests/ui/abi/c-zst.s390x-linux.stderr +++ b/tests/ui/abi/c-zst.s390x-linux.stderr @@ -70,7 +70,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.sparc64-linux.stderr b/tests/ui/abi/c-zst.sparc64-linux.stderr index 308d3a8625638..437ebd63ceba5 100644 --- a/tests/ui/abi/c-zst.sparc64-linux.stderr +++ b/tests/ui/abi/c-zst.sparc64-linux.stderr @@ -70,7 +70,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.x86_64-linux.stderr b/tests/ui/abi/c-zst.x86_64-linux.stderr index a99eb7cd1e830..e7cb6199ab45c 100644 --- a/tests/ui/abi/c-zst.x86_64-linux.stderr +++ b/tests/ui/abi/c-zst.x86_64-linux.stderr @@ -59,7 +59,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/c-zst.x86_64-pc-windows-gnu.stderr b/tests/ui/abi/c-zst.x86_64-pc-windows-gnu.stderr index 308d3a8625638..437ebd63ceba5 100644 --- a/tests/ui/abi/c-zst.x86_64-pc-windows-gnu.stderr +++ b/tests/ui/abi/c-zst.x86_64-pc-windows-gnu.stderr @@ -70,7 +70,7 @@ error: fn_abi_of(pass_zst) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/c-zst.rs:65:1 | diff --git a/tests/ui/abi/debug.generic.stderr b/tests/ui/abi/debug.generic.stderr index ae0edfd7369a2..82c469e0f4f80 100644 --- a/tests/ui/abi/debug.generic.stderr +++ b/tests/ui/abi/debug.generic.stderr @@ -106,7 +106,7 @@ error: fn_abi_of(test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:31:1 | @@ -188,7 +188,7 @@ error: fn_abi_of(TestFnPtr) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:37:1 | @@ -260,7 +260,7 @@ error: fn_abi_of(test_generic) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:40:1 | @@ -339,7 +339,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -406,7 +406,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:59:1 | @@ -486,7 +486,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -560,7 +560,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:62:1 | @@ -633,7 +633,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -700,7 +700,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:65:1 | @@ -773,7 +773,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -840,7 +840,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:69:1 | @@ -935,7 +935,7 @@ error: fn_abi_of(assoc_test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:52:5 | diff --git a/tests/ui/abi/debug.loongarch64.stderr b/tests/ui/abi/debug.loongarch64.stderr index ed20ec1ef3283..b5c73d00564c6 100644 --- a/tests/ui/abi/debug.loongarch64.stderr +++ b/tests/ui/abi/debug.loongarch64.stderr @@ -106,7 +106,7 @@ error: fn_abi_of(test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:31:1 | @@ -188,7 +188,7 @@ error: fn_abi_of(TestFnPtr) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:37:1 | @@ -260,7 +260,7 @@ error: fn_abi_of(test_generic) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:40:1 | @@ -339,7 +339,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -406,7 +406,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:59:1 | @@ -486,7 +486,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -560,7 +560,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:62:1 | @@ -633,7 +633,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -700,7 +700,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:65:1 | @@ -773,7 +773,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -840,7 +840,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:69:1 | @@ -935,7 +935,7 @@ error: fn_abi_of(assoc_test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:52:5 | diff --git a/tests/ui/abi/debug.riscv64.stderr b/tests/ui/abi/debug.riscv64.stderr index ed20ec1ef3283..b5c73d00564c6 100644 --- a/tests/ui/abi/debug.riscv64.stderr +++ b/tests/ui/abi/debug.riscv64.stderr @@ -106,7 +106,7 @@ error: fn_abi_of(test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:31:1 | @@ -188,7 +188,7 @@ error: fn_abi_of(TestFnPtr) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:37:1 | @@ -260,7 +260,7 @@ error: fn_abi_of(test_generic) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:40:1 | @@ -339,7 +339,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -406,7 +406,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:59:1 | @@ -486,7 +486,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -560,7 +560,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:62:1 | @@ -633,7 +633,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -700,7 +700,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:65:1 | @@ -773,7 +773,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } right ABI = FnAbi { args: [ @@ -840,7 +840,7 @@ error: ABIs are not compatible fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:69:1 | @@ -935,7 +935,7 @@ error: fn_abi_of(assoc_test) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: $SOME_BOOL, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/debug.rs:52:5 | diff --git a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr index 927594534d9b8..df49fbfe3d272 100644 --- a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr +++ b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.apple.stderr @@ -69,7 +69,7 @@ error: fn_abi_of(i8) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:13:1 | @@ -147,7 +147,7 @@ error: fn_abi_of(u8) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:19:1 | @@ -225,7 +225,7 @@ error: fn_abi_of(i16) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:25:1 | @@ -303,7 +303,7 @@ error: fn_abi_of(u16) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:31:1 | @@ -381,7 +381,7 @@ error: fn_abi_of(i32) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:37:1 | @@ -459,7 +459,7 @@ error: fn_abi_of(u32) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:43:1 | diff --git a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr index 113ad20e16bc4..7ceb6a2092af2 100644 --- a/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr +++ b/tests/ui/abi/numbers-arithmetic/x86-64-sysv64-arg-ext.other.stderr @@ -69,7 +69,7 @@ error: fn_abi_of(i8) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:13:1 | @@ -147,7 +147,7 @@ error: fn_abi_of(u8) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:19:1 | @@ -225,7 +225,7 @@ error: fn_abi_of(i16) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:25:1 | @@ -303,7 +303,7 @@ error: fn_abi_of(u16) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:31:1 | @@ -381,7 +381,7 @@ error: fn_abi_of(i32) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:37:1 | @@ -459,7 +459,7 @@ error: fn_abi_of(u32) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/x86-64-sysv64-arg-ext.rs:43:1 | diff --git a/tests/ui/abi/pass-indirectly-attr.stderr b/tests/ui/abi/pass-indirectly-attr.stderr index e03828c2e78a4..935ab97647321 100644 --- a/tests/ui/abi/pass-indirectly-attr.stderr +++ b/tests/ui/abi/pass-indirectly-attr.stderr @@ -83,7 +83,7 @@ error: fn_abi_of(extern_c) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/pass-indirectly-attr.rs:20:1 | @@ -175,7 +175,7 @@ error: fn_abi_of(extern_rust) = FnAbi { fixed_count: 1, conv: Rust, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/pass-indirectly-attr.rs:27:1 | diff --git a/tests/ui/abi/sysv64-zst.stderr b/tests/ui/abi/sysv64-zst.stderr index ed8fe5b83fe7c..f19480faec4fa 100644 --- a/tests/ui/abi/sysv64-zst.stderr +++ b/tests/ui/abi/sysv64-zst.stderr @@ -61,7 +61,7 @@ error: fn_abi_of(pass_zst) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/sysv64-zst.rs:8:1 | diff --git a/tests/ui/c-variadic/pass-by-value-abi.aarch64.stderr b/tests/ui/c-variadic/pass-by-value-abi.aarch64.stderr index 7f25ffc3c4481..c616e45a9ab8e 100644 --- a/tests/ui/c-variadic/pass-by-value-abi.aarch64.stderr +++ b/tests/ui/c-variadic/pass-by-value-abi.aarch64.stderr @@ -70,7 +70,7 @@ error: fn_abi_of(take_va_list) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/pass-by-value-abi.rs:27:1 | diff --git a/tests/ui/c-variadic/pass-by-value-abi.win.stderr b/tests/ui/c-variadic/pass-by-value-abi.win.stderr index 150a9262b0f88..638a0856b7b7f 100644 --- a/tests/ui/c-variadic/pass-by-value-abi.win.stderr +++ b/tests/ui/c-variadic/pass-by-value-abi.win.stderr @@ -66,7 +66,7 @@ error: fn_abi_of(take_va_list) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/pass-by-value-abi.rs:27:1 | diff --git a/tests/ui/c-variadic/pass-by-value-abi.x86_64.stderr b/tests/ui/c-variadic/pass-by-value-abi.x86_64.stderr index 1705d3ca7509b..776d0a72287f9 100644 --- a/tests/ui/c-variadic/pass-by-value-abi.x86_64.stderr +++ b/tests/ui/c-variadic/pass-by-value-abi.x86_64.stderr @@ -70,7 +70,7 @@ error: fn_abi_of(take_va_list) = FnAbi { fixed_count: 1, conv: C, can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/pass-by-value-abi.rs:27:1 | @@ -151,7 +151,7 @@ error: fn_abi_of(take_va_list_sysv64) = FnAbi { SysV64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/pass-by-value-abi.rs:37:1 | @@ -232,7 +232,7 @@ error: fn_abi_of(take_va_list_win64) = FnAbi { Win64, ), can_unwind: false, - ptrauth_discriminator: 0, + ptrauth_discriminator: None, } --> $DIR/pass-by-value-abi.rs:44:1 | From 133ed3bec01c4a1250760f7dfad5741efe02eb92 Mon Sep 17 00:00:00 2001 From: Jakub Chlanda Date: Fri, 10 Jul 2026 12:16:40 +0000 Subject: [PATCH 3/5] [PAC] Enable support for FPTR_TYPE_DISCR in ABI Version Also remove error messages/tests that used to guarded it. --- compiler/rustc_session/src/diagnostics.rs | 6 ------ compiler/rustc_session/src/session.rs | 21 +++++-------------- ...on_not_supported_pointer_authentication.rs | 12 ----------- ...ot_supported_pointer_authentication.stderr | 4 ---- 4 files changed, 5 insertions(+), 38 deletions(-) delete mode 100644 tests/ui/pointer_authentication/type_discrimination_not_supported_pointer_authentication.rs delete mode 100644 tests/ui/pointer_authentication/type_discrimination_not_supported_pointer_authentication.stderr diff --git a/compiler/rustc_session/src/diagnostics.rs b/compiler/rustc_session/src/diagnostics.rs index e8f29d8a9ee77..deb786245197b 100644 --- a/compiler/rustc_session/src/diagnostics.rs +++ b/compiler/rustc_session/src/diagnostics.rs @@ -381,12 +381,6 @@ pub(crate) struct StackProtectorNotSupportedForTarget<'a> { pub(crate) target_triple: &'a TargetTuple, } -#[derive(Diagnostic)] -#[diag("function pointer type discrimination is not supported")] -pub(crate) struct PointerAuthenticationTypeDiscriminationNotSupportedForTarget<'a> { - pub(crate) target_triple: &'a TargetTuple, -} - #[derive(Diagnostic)] #[diag( "`-Z pointer-authentication` is not supported for target {$target_triple} and will be ignored" diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs index e31176a88acee..8db8cd163e6e0 100644 --- a/compiler/rustc_session/src/session.rs +++ b/compiler/rustc_session/src/session.rs @@ -208,8 +208,7 @@ impl PointerAuthConfig { const GOT: u32 = 8; const GOTOS: u32 = 9; const TYPEINFO_VT_PTR_DISCR: u32 = 10; - // FIXME(jchlanda) We don't yet support function pointer type discrimination. - // const FPTR_TYPE_DISCR: u32 = 11; + const FPTR_TYPE_DISCR: u32 = 11; let pauth_abi_version: u32 = (u32::from(self.intrinsics) << INTRINSICS) | (u32::from(self.function_pointers.is_some()) << CALLS) @@ -227,7 +226,10 @@ impl PointerAuthConfig { })) << INIT_FINI_ADDR_DISC) | (u32::from(self.elf_got) << GOT) | (u32::from(self.indirect_gotos) << GOTOS) - | (u32::from(self.typeinfo_vt_ptr_discrimination) << TYPEINFO_VT_PTR_DISCR); + | (u32::from(self.typeinfo_vt_ptr_discrimination) << TYPEINFO_VT_PTR_DISCR) + | (u32::from(self.function_pointers.as_ref().is_some_and(|schema| { + matches!(schema.discrimination_kind, PointerAuthDiscrimination::Type) + })) << FPTR_TYPE_DISCR); pauth_abi_version } @@ -1469,19 +1471,6 @@ fn validate_commandline_args_with_session_available(sess: &Session) { sess.dcx().emit_err(diagnostics::LinkerPluginToWindowsNotSupported); } - if sess - .pointer_auth_config - .as_ref() - .and_then(|cfg| cfg.function_pointers.as_ref()) - .is_some_and(|schema| matches!(schema.discrimination_kind, PointerAuthDiscrimination::Type)) - { - sess.dcx().emit_err( - diagnostics::PointerAuthenticationTypeDiscriminationNotSupportedForTarget { - target_triple: &sess.opts.target_triple, - }, - ); - } - if sess.target.cfg_abi != CfgAbi::Pauthtest && !sess.opts.unstable_opts.pointer_authentication.is_empty() { diff --git a/tests/ui/pointer_authentication/type_discrimination_not_supported_pointer_authentication.rs b/tests/ui/pointer_authentication/type_discrimination_not_supported_pointer_authentication.rs deleted file mode 100644 index 6838e749fd333..0000000000000 --- a/tests/ui/pointer_authentication/type_discrimination_not_supported_pointer_authentication.rs +++ /dev/null @@ -1,12 +0,0 @@ -//@ ignore-backends: gcc -//@ check-fail -//@ needs-llvm-components: aarch64 - -//@ compile-flags: -Zpointer-authentication=+function-pointer-type-discrimination --crate-type=lib --target aarch64-unknown-linux-pauthtest - -#![feature(no_core)] -#![no_std] -#![no_main] -#![no_core] - -//~? ERROR function pointer type discrimination is not supported diff --git a/tests/ui/pointer_authentication/type_discrimination_not_supported_pointer_authentication.stderr b/tests/ui/pointer_authentication/type_discrimination_not_supported_pointer_authentication.stderr deleted file mode 100644 index c040b0cb61f66..0000000000000 --- a/tests/ui/pointer_authentication/type_discrimination_not_supported_pointer_authentication.stderr +++ /dev/null @@ -1,4 +0,0 @@ -error: function pointer type discrimination is not supported - -error: aborting due to 1 previous error - From e17da63c1320399f3e044d5f3f2a1515dbe226c4 Mon Sep 17 00:00:00 2001 From: Jakub Chlanda Date: Fri, 10 Jul 2026 12:59:12 +0000 Subject: [PATCH 4/5] [PAC] Support type discriminators in static allocations The codegen now walks the layout of static initializer types to find extern "C" function pointer fields, computes their type discriminators, and applies those discriminators when emitting authenticated function pointer relocations. Also make sure that type discrimination is never applied to init/fini entries. --- compiler/rustc_codegen_gcc/src/common.rs | 4 +- compiler/rustc_codegen_llvm/src/asm.rs | 8 +- compiler/rustc_codegen_llvm/src/common.rs | 20 ++- compiler/rustc_codegen_llvm/src/consts.rs | 169 +++++++++++++++++- .../rustc_codegen_ssa/src/traits/consts.rs | 5 +- 5 files changed, 194 insertions(+), 12 deletions(-) diff --git a/compiler/rustc_codegen_gcc/src/common.rs b/compiler/rustc_codegen_gcc/src/common.rs index 712a1c14ef8e6..80396e7eb70de 100644 --- a/compiler/rustc_codegen_gcc/src/common.rs +++ b/compiler/rustc_codegen_gcc/src/common.rs @@ -1,9 +1,10 @@ use gccjit::{GlobalKind, LValue, RValue, ToRValue, Type}; use rustc_abi::Primitive::Pointer; -use rustc_abi::{self as abi, HasDataLayout}; +use rustc_abi::{self as abi, HasDataLayout, Size}; use rustc_codegen_ssa::traits::{ BaseTypeCodegenMethods, ConstCodegenMethods, MiscCodegenMethods, StaticCodegenMethods, }; +use rustc_data_structures::fx::FxHashMap; use rustc_middle::mir::Mutability; use rustc_middle::mir::interpret::{GlobalAlloc, PointerArithmetic, Scalar}; use rustc_middle::ty::layout::LayoutOf; @@ -324,6 +325,7 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> { layout: abi::Scalar, ty: Type<'gcc>, _ptrauth_schema: Option, + _ptrauth_discriminators: Option<&FxHashMap>, ) -> RValue<'gcc> { let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() }; match cv { diff --git a/compiler/rustc_codegen_llvm/src/asm.rs b/compiler/rustc_codegen_llvm/src/asm.rs index 0f74f5e81d684..8e71e587235c6 100644 --- a/compiler/rustc_codegen_llvm/src/asm.rs +++ b/compiler/rustc_codegen_llvm/src/asm.rs @@ -165,7 +165,8 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> { ConstScalar::Ptr(ptr, _) => { let (prov, _) = ptr.prov_and_relative_offset(); let global_alloc = self.tcx.global_alloc(prov.alloc_id()); - let value = self.cx.alloc_to_backend(global_alloc, false, None).unwrap(); + let value = + self.cx.alloc_to_backend(global_alloc, false, None, None).unwrap(); inputs.push(value); op_idx.insert(idx, constraints.len()); constraints.push("s".to_string()); @@ -455,8 +456,9 @@ impl<'tcx> AsmCodegenMethods<'tcx> for CodegenCx<'_, 'tcx> { ConstScalar::Ptr(ptr, _) => { let (prov, offset) = ptr.prov_and_relative_offset(); let global_alloc = self.tcx.global_alloc(prov.alloc_id()); - let llval = - self.alloc_to_backend(global_alloc, true, None).unwrap(); + let llval = self + .alloc_to_backend(global_alloc, true, None, None) + .unwrap(); self.add_compiler_used_global(llval); let symbol = llvm::build_string(|s| unsafe { diff --git a/compiler/rustc_codegen_llvm/src/common.rs b/compiler/rustc_codegen_llvm/src/common.rs index 8f63e409028ce..3892ad7ab3dea 100644 --- a/compiler/rustc_codegen_llvm/src/common.rs +++ b/compiler/rustc_codegen_llvm/src/common.rs @@ -4,11 +4,12 @@ use std::borrow::Borrow; use libc::{c_char, c_uint}; use rustc_abi::Primitive::Pointer; -use rustc_abi::{self as abi, ExternAbi, HasDataLayout as _}; +use rustc_abi::{self as abi, ExternAbi, HasDataLayout as _, Size}; use rustc_ast::Mutability; use rustc_codegen_ssa::common::TypeKind; use rustc_codegen_ssa::traits::*; use rustc_crate_store::DllImport; +use rustc_data_structures::fx::FxHashMap; use rustc_data_structures::stable_hash::{StableHash, StableHasher}; use rustc_hashes::Hash128; use rustc_hir::def::DefKind; @@ -183,6 +184,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> { global_alloc: GlobalAlloc<'tcx>, need_symbol_name: bool, ptrauth_schema: Option, + ptrauth_discriminators: Option<&FxHashMap>, ) -> Result<&'ll Value, u64> { let alloc = match global_alloc { GlobalAlloc::Function { instance, .. } => { @@ -229,7 +231,13 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> { } }; - let init = const_alloc_to_llvm(self, alloc.inner(), IsStatic::No, IsInitOrFini::No); + let init = const_alloc_to_llvm( + self, + alloc.inner(), + IsStatic::No, + IsInitOrFini::No, + ptrauth_discriminators, + ); let alloc = alloc.inner(); if need_symbol_name { @@ -409,6 +417,7 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> { layout: abi::Scalar, llty: &'ll Type, ptrauth_schema: Option, + ptrauth_discriminators: Option<&FxHashMap>, ) -> &'ll Value { let bitsize = if layout.is_bool() { 1 } else { layout.size(self).bits() }; match cv { @@ -425,7 +434,12 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> { let (prov, offset) = ptr.prov_and_relative_offset(); let global_alloc = self.tcx.global_alloc(prov.alloc_id()); let base_addr_space = global_alloc.address_space(self); - let base_addr = match self.alloc_to_backend(global_alloc, false, ptrauth_schema) { + let base_addr = match self.alloc_to_backend( + global_alloc, + false, + ptrauth_schema, + ptrauth_discriminators, + ) { Ok(base_addr) => base_addr, Err(base_addr) => { let val = base_addr.wrapping_add(offset.bytes()); diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs index 8ecbcf72b1ea4..64849b4eef1d8 100644 --- a/compiler/rustc_codegen_llvm/src/consts.rs +++ b/compiler/rustc_codegen_llvm/src/consts.rs @@ -3,6 +3,7 @@ use std::ops::Range; use rustc_abi::{Align, ExternAbi, HasDataLayout, Primitive, Scalar, Size, WrappingRange}; use rustc_codegen_ssa::common; use rustc_codegen_ssa::traits::*; +use rustc_data_structures::fx::FxHashMap; use rustc_hir::attrs::Linkage; use rustc_hir::attrs::lang_items::LangItem; use rustc_hir::def::DefKind; @@ -13,8 +14,9 @@ use rustc_middle::mir::interpret::{ read_target_uint, }; use rustc_middle::mono::MonoItem; +use rustc_middle::ptrauth::ptrauth_compute_fn_ptr_type_discriminator_for; use rustc_middle::ty::layout::{HasTypingEnv, LayoutOf}; -use rustc_middle::ty::{self, Instance}; +use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; use rustc_middle::{bug, span_bug}; use rustc_span::Symbol; use rustc_target::spec::Arch; @@ -37,11 +39,135 @@ pub(crate) enum IsInitOrFini { Yes, No, } + +/// Recursively walks a type layout and records the offsets of all extern "C" +/// function pointer fields together with their computed type discriminators. +/// +/// Traversal currently supports: +/// - references +/// - direct function pointers +/// - structs +/// - tuples +/// - arrays +/// +/// Offsets are accumulated relative to the containing object. +fn collect_fn_ptr_discriminators<'tcx>( + tcx: TyCtxt<'tcx>, + typing_env: ty::TypingEnv<'tcx>, + ty: Ty<'tcx>, +) -> FxHashMap { + let mut map = FxHashMap::default(); + + collect_fn_ptr_discriminators_inner(tcx, typing_env, ty, Size::ZERO, &mut map); + + map +} + +fn collect_fn_ptr_discriminators_inner<'tcx>( + tcx: TyCtxt<'tcx>, + typing_env: ty::TypingEnv<'tcx>, + ty: Ty<'tcx>, + base_offset: Size, + map: &mut FxHashMap, +) { + // Direct function pointer. + if let Some(disc) = ptrauth_compute_fn_ptr_type_discriminator_for(tcx, ty) { + map.insert(base_offset, disc.into()); + + return; + } + + match ty.kind() { + ty::Ref(_, pointee, _) => { + collect_fn_ptr_discriminators_inner(tcx, typing_env, *pointee, base_offset, map); + } + ty::Adt(def, args) if def.is_struct() => { + let Ok(layout) = tcx.layout_of(typing_env.as_query_input(ty)) else { + return; + }; + + let variant = def.non_enum_variant(); + + for (idx, field_def) in variant.fields.iter_enumerated() { + let field_ty = tcx.normalize_erasing_regions(typing_env, field_def.ty(tcx, args)); + + let field_offset = layout.fields.offset(idx.into()); + + collect_fn_ptr_discriminators_inner( + tcx, + typing_env, + field_ty, + base_offset + field_offset, + map, + ); + } + } + ty::Tuple(fields) => { + let Ok(layout) = tcx.layout_of(typing_env.as_query_input(ty)) else { + return; + }; + + for (idx, field_ty) in fields.iter().enumerate() { + let field_offset = layout.fields.offset(idx); + + collect_fn_ptr_discriminators_inner( + tcx, + typing_env, + field_ty, + base_offset + field_offset, + map, + ); + } + } + ty::Array(elem_ty, len) => { + let count = match len.try_to_target_usize(tcx) { + Some(v) => v, + None => return, + }; + + let Ok(elem_layout) = tcx.layout_of(typing_env.as_query_input(*elem_ty)) else { + return; + }; + + let stride = elem_layout.size; + + // Collect discriminator of one element, so we don't have to recompute it for all the + // elements in the array. + let mut elem_map = FxHashMap::default(); + + collect_fn_ptr_discriminators_inner( + tcx, + typing_env, + *elem_ty, + Size::ZERO, + &mut elem_map, + ); + + // SAFETY: We immediately collect into a Vec and sort by offset. + // The HashMap iteration order is irrelevant and must not affect determinism. + #[allow(rustc::potential_query_instability)] + let mut entries: Vec<(Size, u64)> = elem_map.into_iter().collect(); + entries.sort_unstable_by_key(|(offset, _)| *offset); + + // Replicate for every array slot. + for i in 0..count { + let elem_base = base_offset + stride * i; + + for (inner_offset, discr) in entries.iter().copied() { + map.insert(elem_base + inner_offset, discr); + } + } + } + _ => {} + } +} + pub(crate) fn const_alloc_to_llvm<'ll>( cx: &CodegenCx<'ll, '_>, alloc: &Allocation, is_static: IsStatic, is_init_fini: IsInitOrFini, + ptrauth_discriminators: Option<&FxHashMap>, ) -> &'ll Value { // We expect that callers of const_alloc_to_llvm will instead directly codegen a pointer or // integer for any &ZST where the ZST is a constant (i.e. not a static). We should never be @@ -121,7 +247,7 @@ pub(crate) fn const_alloc_to_llvm<'ll>( as u64; let address_space = cx.tcx.global_alloc(prov.alloc_id()).address_space(cx); - let schema = if cx.sess().pointer_authentication() { + let mut schema = if cx.sess().pointer_authentication() { match is_init_fini { IsInitOrFini::Yes => cx.sess().pointer_authentication_init_fini(), IsInitOrFini::No => cx.sess().pointer_authentication_functions(), @@ -129,6 +255,16 @@ pub(crate) fn const_alloc_to_llvm<'ll>( } else { None }; + let discr = + ptrauth_discriminators.as_ref().and_then(|m| m.get(&Size::from_bytes(offset as u64))); + + // Init/fini entries must not participate in function pointer type discrimination, they use + // a dedicated constant value (ptrauth_string_discriminator("init_fini") which is: 0xd9d4). + if let (Some(schema), Some(discr)) = (schema.as_mut(), discr) + && is_init_fini == IsInitOrFini::No + { + schema.constant_discriminator = *discr as u16; + } llvals.push(cx.scalar_to_backend_with_pac( InterpScalar::from_pointer(Pointer::new(prov, Size::from_bytes(ptr_offset)), &cx.tcx), Scalar::Initialized { @@ -137,6 +273,7 @@ pub(crate) fn const_alloc_to_llvm<'ll>( }, cx.type_ptr_ext(address_space), schema, + ptrauth_discriminators, )); next_offset = offset + pointer_size_bytes; } @@ -160,6 +297,15 @@ fn codegen_static_initializer<'ll, 'tcx>( cx: &CodegenCx<'ll, 'tcx>, def_id: DefId, ) -> Result<(&'ll Value, ConstAllocation<'tcx>), ErrorHandled> { + let ptrauth_discriminators = if cx.sess().pointer_authentication_fn_ptr_type_discrimination() { + let instance = Instance::mono(cx.tcx, def_id); + let ty = instance.ty(cx.tcx, cx.typing_env()); + + Some(collect_fn_ptr_discriminators(cx.tcx, cx.typing_env(), ty)) + } else { + None + }; + let alloc = cx.tcx.eval_static_initializer(def_id)?; let attrs = cx.tcx.codegen_fn_attrs(def_id); // FIXME(jchlanda) Decide if this could be better served by `ctor` crate. See the discussion @@ -175,7 +321,16 @@ fn codegen_static_initializer<'ll, 'tcx>( } }) .unwrap_or(IsInitOrFini::No); - Ok((const_alloc_to_llvm(cx, alloc.inner(), IsStatic::Yes, is_in_init_fini), alloc)) + Ok(( + const_alloc_to_llvm( + cx, + alloc.inner(), + IsStatic::Yes, + is_in_init_fini, + ptrauth_discriminators.as_ref(), + ), + alloc, + )) } fn set_global_alignment<'ll>(cx: &CodegenCx<'ll, '_>, gv: &'ll Value, mut align: Align) { @@ -837,7 +992,13 @@ impl<'ll> StaticCodegenMethods for CodegenCx<'ll, '_> { fn static_addr_of(&self, alloc: ConstAllocation<'_>, kind: Option<&str>) -> &'ll Value { // FIXME: should we cache `const_alloc_to_llvm` to avoid repeating this for the // same `ConstAllocation`? - let cv = const_alloc_to_llvm(self, alloc.inner(), IsStatic::No, IsInitOrFini::No); + // FIXME(jchlanda): Add support for pointer authentication type discrimination. + // `static_addr_of` only receives a `ConstAllocation`, so it does not have the type + // information needed to compute function pointer type discriminators. We'll likely need + // to either compute the discriminator map at callers that still know the Rust type, or + // extend this API to accept the required type information. See + // `codegen_static_initializer` for an example of how the discriminator map is computed. + let cv = const_alloc_to_llvm(self, alloc.inner(), IsStatic::No, IsInitOrFini::No, None); let gv = self.static_addr_of_impl(cv, alloc.inner().align, kind); // static_addr_of_impl returns the bare global variable, which might not be in the default diff --git a/compiler/rustc_codegen_ssa/src/traits/consts.rs b/compiler/rustc_codegen_ssa/src/traits/consts.rs index b45b5667be6c9..7f82ebda2e5fb 100644 --- a/compiler/rustc_codegen_ssa/src/traits/consts.rs +++ b/compiler/rustc_codegen_ssa/src/traits/consts.rs @@ -1,4 +1,6 @@ use rustc_abi as abi; +use rustc_abi::Size; +use rustc_data_structures::fx::FxHashMap; use rustc_middle::mir::interpret::Scalar; use rustc_session::PointerAuthSchema; @@ -40,7 +42,7 @@ pub trait ConstCodegenMethods: BackendTypes { fn const_to_opt_u128(&self, v: Self::Value, sign_ext: bool) -> Option; fn scalar_to_backend(&self, cv: Scalar, layout: abi::Scalar, llty: Self::Type) -> Self::Value { - self.scalar_to_backend_with_pac(cv, layout, llty, None) + self.scalar_to_backend_with_pac(cv, layout, llty, None, None) } fn scalar_to_backend_with_pac( &self, @@ -48,6 +50,7 @@ pub trait ConstCodegenMethods: BackendTypes { layout: abi::Scalar, llty: Self::Type, ptrauth_schema: Option, + ptrauth_discriminators: Option<&FxHashMap>, ) -> Self::Value; fn const_ptr_byte_offset(&self, val: Self::Value, offset: abi::Size) -> Self::Value; From 19c8accc32904840b57093d368ec5dd0eb233b0e Mon Sep 17 00:00:00 2001 From: Jakub Chlanda Date: Wed, 29 Jul 2026 14:18:57 +0000 Subject: [PATCH 5/5] [PAC] Extend support to compile-time constants This covers standalone function pointer constants, promoted temporaries, immutable and mutable statics, arrays of function pointers, and mixed structs containing function pointers. Consult pauth-fn-ptr-type-discrimination-static-allocs.rs test for example uses. Revolves around threading PAC information through: * static_addr_of (StaticCodegenMethods) * from_const and from_const_alloc (both on rustc_codegen_ssa::mir::operand / OperandRef) --- compiler/rustc_codegen_gcc/src/common.rs | 2 +- compiler/rustc_codegen_gcc/src/consts.rs | 8 +- compiler/rustc_codegen_llvm/src/consts.rs | 149 ++-------------- compiler/rustc_codegen_ssa/src/meth.rs | 5 +- compiler/rustc_codegen_ssa/src/mir/operand.rs | 43 ++++- compiler/rustc_codegen_ssa/src/mir/retag.rs | 4 +- .../rustc_codegen_ssa/src/traits/statics.rs | 10 +- .../rustc_middle/src/ptrauth/discriminator.rs | 160 ++++++++++++++++-- compiler/rustc_middle/src/ptrauth/mod.rs | 2 +- compiler/rustc_middle/src/ty/vtable.rs | 23 +++ 10 files changed, 255 insertions(+), 151 deletions(-) diff --git a/compiler/rustc_codegen_gcc/src/common.rs b/compiler/rustc_codegen_gcc/src/common.rs index 80396e7eb70de..0b8b046f49c7d 100644 --- a/compiler/rustc_codegen_gcc/src/common.rs +++ b/compiler/rustc_codegen_gcc/src/common.rs @@ -116,7 +116,7 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> { Mutability::Mut => { self.static_addr_of_mut(const_alloc_to_gcc(self, alloc), alloc.inner().align, None) } - _ => self.static_addr_of(alloc, None), + _ => self.static_addr_of(alloc, None, None), }; if !self.sess().fewer_names() { // FIXME(antoyo): set value name. diff --git a/compiler/rustc_codegen_gcc/src/consts.rs b/compiler/rustc_codegen_gcc/src/consts.rs index 42ff930968501..a25073f964eaf 100644 --- a/compiler/rustc_codegen_gcc/src/consts.rs +++ b/compiler/rustc_codegen_gcc/src/consts.rs @@ -5,6 +5,7 @@ use rustc_abi::{self as abi, Align, HasDataLayout, Primitive, Size, WrappingRang use rustc_codegen_ssa::traits::{ BaseTypeCodegenMethods, ConstCodegenMethods, StaticCodegenMethods, }; +use rustc_data_structures::fx::FxHashMap; use rustc_hir::attrs::Linkage; use rustc_hir::def::DefKind; use rustc_hir::def_id::LOCAL_CRATE; @@ -56,7 +57,12 @@ fn set_global_alignment<'gcc, 'tcx>( } impl<'gcc, 'tcx> StaticCodegenMethods for CodegenCx<'gcc, 'tcx> { - fn static_addr_of(&self, alloc: ConstAllocation<'_>, kind: Option<&str>) -> RValue<'gcc> { + fn static_addr_of( + &self, + alloc: ConstAllocation<'_>, + kind: Option<&str>, + _ptrauth_discriminators: Option<&FxHashMap>, + ) -> RValue<'gcc> { let cv = const_alloc_to_gcc(self, alloc); let align = alloc.inner().align; diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs index 64849b4eef1d8..fd91942f018dc 100644 --- a/compiler/rustc_codegen_llvm/src/consts.rs +++ b/compiler/rustc_codegen_llvm/src/consts.rs @@ -14,9 +14,9 @@ use rustc_middle::mir::interpret::{ read_target_uint, }; use rustc_middle::mono::MonoItem; -use rustc_middle::ptrauth::ptrauth_compute_fn_ptr_type_discriminator_for; +use rustc_middle::ptrauth::ptrauth_collect_fn_ptr_discriminators; use rustc_middle::ty::layout::{HasTypingEnv, LayoutOf}; -use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; +use rustc_middle::ty::{self, Instance}; use rustc_middle::{bug, span_bug}; use rustc_span::Symbol; use rustc_target::spec::Arch; @@ -40,128 +40,6 @@ pub(crate) enum IsInitOrFini { No, } -/// Recursively walks a type layout and records the offsets of all extern "C" -/// function pointer fields together with their computed type discriminators. -/// -/// Traversal currently supports: -/// - references -/// - direct function pointers -/// - structs -/// - tuples -/// - arrays -/// -/// Offsets are accumulated relative to the containing object. -fn collect_fn_ptr_discriminators<'tcx>( - tcx: TyCtxt<'tcx>, - typing_env: ty::TypingEnv<'tcx>, - ty: Ty<'tcx>, -) -> FxHashMap { - let mut map = FxHashMap::default(); - - collect_fn_ptr_discriminators_inner(tcx, typing_env, ty, Size::ZERO, &mut map); - - map -} - -fn collect_fn_ptr_discriminators_inner<'tcx>( - tcx: TyCtxt<'tcx>, - typing_env: ty::TypingEnv<'tcx>, - ty: Ty<'tcx>, - base_offset: Size, - map: &mut FxHashMap, -) { - // Direct function pointer. - if let Some(disc) = ptrauth_compute_fn_ptr_type_discriminator_for(tcx, ty) { - map.insert(base_offset, disc.into()); - - return; - } - - match ty.kind() { - ty::Ref(_, pointee, _) => { - collect_fn_ptr_discriminators_inner(tcx, typing_env, *pointee, base_offset, map); - } - ty::Adt(def, args) if def.is_struct() => { - let Ok(layout) = tcx.layout_of(typing_env.as_query_input(ty)) else { - return; - }; - - let variant = def.non_enum_variant(); - - for (idx, field_def) in variant.fields.iter_enumerated() { - let field_ty = tcx.normalize_erasing_regions(typing_env, field_def.ty(tcx, args)); - - let field_offset = layout.fields.offset(idx.into()); - - collect_fn_ptr_discriminators_inner( - tcx, - typing_env, - field_ty, - base_offset + field_offset, - map, - ); - } - } - ty::Tuple(fields) => { - let Ok(layout) = tcx.layout_of(typing_env.as_query_input(ty)) else { - return; - }; - - for (idx, field_ty) in fields.iter().enumerate() { - let field_offset = layout.fields.offset(idx); - - collect_fn_ptr_discriminators_inner( - tcx, - typing_env, - field_ty, - base_offset + field_offset, - map, - ); - } - } - ty::Array(elem_ty, len) => { - let count = match len.try_to_target_usize(tcx) { - Some(v) => v, - None => return, - }; - - let Ok(elem_layout) = tcx.layout_of(typing_env.as_query_input(*elem_ty)) else { - return; - }; - - let stride = elem_layout.size; - - // Collect discriminator of one element, so we don't have to recompute it for all the - // elements in the array. - let mut elem_map = FxHashMap::default(); - - collect_fn_ptr_discriminators_inner( - tcx, - typing_env, - *elem_ty, - Size::ZERO, - &mut elem_map, - ); - - // SAFETY: We immediately collect into a Vec and sort by offset. - // The HashMap iteration order is irrelevant and must not affect determinism. - #[allow(rustc::potential_query_instability)] - let mut entries: Vec<(Size, u64)> = elem_map.into_iter().collect(); - entries.sort_unstable_by_key(|(offset, _)| *offset); - - // Replicate for every array slot. - for i in 0..count { - let elem_base = base_offset + stride * i; - - for (inner_offset, discr) in entries.iter().copied() { - map.insert(elem_base + inner_offset, discr); - } - } - } - _ => {} - } -} - pub(crate) fn const_alloc_to_llvm<'ll>( cx: &CodegenCx<'ll, '_>, alloc: &Allocation, @@ -301,7 +179,7 @@ fn codegen_static_initializer<'ll, 'tcx>( let instance = Instance::mono(cx.tcx, def_id); let ty = instance.ty(cx.tcx, cx.typing_env()); - Some(collect_fn_ptr_discriminators(cx.tcx, cx.typing_env(), ty)) + Some(ptrauth_collect_fn_ptr_discriminators(cx.tcx, cx.typing_env(), ty)) } else { None }; @@ -989,16 +867,21 @@ impl<'ll> StaticCodegenMethods for CodegenCx<'ll, '_> { /// /// The pointer will always be in the default address space. If global variables default to a /// different address space, an addrspacecast is inserted. - fn static_addr_of(&self, alloc: ConstAllocation<'_>, kind: Option<&str>) -> &'ll Value { + fn static_addr_of( + &self, + alloc: ConstAllocation<'_>, + kind: Option<&str>, + ptrauth_discriminators: Option<&FxHashMap>, + ) -> &'ll Value { // FIXME: should we cache `const_alloc_to_llvm` to avoid repeating this for the // same `ConstAllocation`? - // FIXME(jchlanda): Add support for pointer authentication type discrimination. - // `static_addr_of` only receives a `ConstAllocation`, so it does not have the type - // information needed to compute function pointer type discriminators. We'll likely need - // to either compute the discriminator map at callers that still know the Rust type, or - // extend this API to accept the required type information. See - // `codegen_static_initializer` for an example of how the discriminator map is computed. - let cv = const_alloc_to_llvm(self, alloc.inner(), IsStatic::No, IsInitOrFini::No, None); + let cv = const_alloc_to_llvm( + self, + alloc.inner(), + IsStatic::No, + IsInitOrFini::No, + ptrauth_discriminators, + ); let gv = self.static_addr_of_impl(cv, alloc.inner().align, kind); // static_addr_of_impl returns the bare global variable, which might not be in the default diff --git a/compiler/rustc_codegen_ssa/src/meth.rs b/compiler/rustc_codegen_ssa/src/meth.rs index b87034f9b33b7..959812b67e894 100644 --- a/compiler/rustc_codegen_ssa/src/meth.rs +++ b/compiler/rustc_codegen_ssa/src/meth.rs @@ -114,7 +114,10 @@ pub(crate) fn get_vtable<'tcx, Cx: CodegenMethods<'tcx>>( let vtable_alloc_id = tcx.vtable_allocation((ty, trait_ref)); let vtable_allocation = tcx.global_alloc(vtable_alloc_id).unwrap_memory(); - let vtable = cx.static_addr_of(vtable_allocation, Some("vtable")); + // Vtables cannot contain extern "C"/"System" function pointers (asserted in + // vtable_allocation_provider), so they do not require function pointer type + // discriminators. + let vtable = cx.static_addr_of(vtable_allocation, Some("vtable"), None); cx.apply_vcall_visibility_metadata(ty, trait_ref, vtable); cx.create_vtable_debuginfo(ty, trait_ref, vtable); diff --git a/compiler/rustc_codegen_ssa/src/mir/operand.rs b/compiler/rustc_codegen_ssa/src/mir/operand.rs index c1a1b2db6fa9d..8e39a4de8c53b 100644 --- a/compiler/rustc_codegen_ssa/src/mir/operand.rs +++ b/compiler/rustc_codegen_ssa/src/mir/operand.rs @@ -8,6 +8,7 @@ use rustc_abi::{ use rustc_hir::attrs::lang_items::LangItem; use rustc_middle::mir::interpret::{Pointer, Scalar, alloc_range}; use rustc_middle::mir::{self, ConstValue}; +use rustc_middle::ptrauth::ptrauth_collect_fn_ptr_discriminators; use rustc_middle::ty::layout::{LayoutOf, TyAndLayout}; use rustc_middle::ty::{self, Ty}; use rustc_middle::{bug, span_bug}; @@ -182,7 +183,34 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> { let BackendRepr::Scalar(scalar) = layout.backend_repr else { bug!("from_const: invalid ByVal layout: {:#?}", layout); }; - let llval = bx.scalar_to_backend(x, scalar, bx.immediate_backend_type(layout)); + let llval = match x { + Scalar::Ptr(..) => { + let pointee_ty = match ty.kind() { + ty::Ref(_, pointee, _) => *pointee, + _ => ty, + }; + let ptrauth_discriminators = + if bx.tcx().sess.pointer_authentication_fn_ptr_type_discrimination() { + Some(ptrauth_collect_fn_ptr_discriminators( + bx.tcx(), + bx.typing_env(), + pointee_ty, + )) + } else { + None + }; + let ptrauth_schema = bx.sess().pointer_authentication_functions(); + bx.scalar_to_backend_with_pac( + x, + scalar, + bx.immediate_backend_type(layout), + ptrauth_schema, + ptrauth_discriminators.as_ref(), + ) + } + _ => bx.scalar_to_backend(x, scalar, bx.immediate_backend_type(layout)), + }; + OperandValue::Immediate(llval) } ConstValue::ZeroSized => return OperandRef::zero_sized(layout), @@ -267,8 +295,19 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> { } _ if layout.is_zst() => OperandRef::zero_sized(layout), _ => { + let ptrauth_discriminators = + if bx.tcx().sess.pointer_authentication_fn_ptr_type_discrimination() { + Some(ptrauth_collect_fn_ptr_discriminators( + bx.tcx(), + bx.typing_env(), + layout.ty, + )) + } else { + None + }; + // Neither a scalar nor scalar pair. Load from a place - let base_addr = bx.static_addr_of(alloc, None); + let base_addr = bx.static_addr_of(alloc, None, ptrauth_discriminators.as_ref()); let llval = bx.const_ptr_byte_offset(base_addr, offset); bx.load_operand(PlaceRef::new_sized(llval, layout)) diff --git a/compiler/rustc_codegen_ssa/src/mir/retag.rs b/compiler/rustc_codegen_ssa/src/mir/retag.rs index 397fb423e8da3..725f1302170ed 100644 --- a/compiler/rustc_codegen_ssa/src/mir/retag.rs +++ b/compiler/rustc_codegen_ssa/src/mir/retag.rs @@ -271,7 +271,9 @@ impl<'a, 'tcx, V> RetagPlan { let global_alloc = tcx.global_alloc(alloc_id); let global_mem = global_alloc.unwrap_memory(); - bx.cx().static_addr_of(global_mem, None) + // The range table contains only integer data, not pointer relocations, so no ptrauth + // discriminators are needed. + bx.cx().static_addr_of(global_mem, None, None) } } diff --git a/compiler/rustc_codegen_ssa/src/traits/statics.rs b/compiler/rustc_codegen_ssa/src/traits/statics.rs index c726213025350..20394c98812c1 100644 --- a/compiler/rustc_codegen_ssa/src/traits/statics.rs +++ b/compiler/rustc_codegen_ssa/src/traits/statics.rs @@ -1,10 +1,18 @@ +use rustc_abi::Size; +use rustc_data_structures::fx::FxHashMap; use rustc_hir::def_id::DefId; use rustc_middle::mir::interpret::ConstAllocation; use super::BackendTypes; pub trait StaticCodegenMethods: BackendTypes { - fn static_addr_of(&self, alloc: ConstAllocation<'_>, kind: Option<&str>) -> Self::Value; + fn static_addr_of( + &self, + alloc: ConstAllocation<'_>, + kind: Option<&str>, + ptrauth_discriminators: Option<&FxHashMap>, + ) -> Self::Value; + fn codegen_static(&mut self, def_id: DefId); } diff --git a/compiler/rustc_middle/src/ptrauth/discriminator.rs b/compiler/rustc_middle/src/ptrauth/discriminator.rs index 7501f1b072188..da7518823d47d 100644 --- a/compiler/rustc_middle/src/ptrauth/discriminator.rs +++ b/compiler/rustc_middle/src/ptrauth/discriminator.rs @@ -1,11 +1,13 @@ //! Function pointer type discrimination for pointer authentication. //! This module implements Rust's equivalent of Clang's function pointer type -//! discriminator computation used in pointer authentication. +//! discriminator computation used in pointer authentication, as well as the +//! machinery required to locate function pointer fields in Rust layouts that +//! require such discriminators. //! //! Compatibility with Clang is a primary goal. The discriminator produced for a -//! given external "C" function type must match the value computed by Clang so that -//! function pointers can be exchanged safely between Rust and C code while +//! given external "C" function type must match the value computed by Clang so +//! that function pointers can be exchanged safely between Rust and C code while //! preserving pointer authentication semantics. //! //! The implementation mirrors Clang's behavior in @@ -15,14 +17,16 @@ //! //! ## Overview //! -//! The computation is structured into three conceptual stages: +//! The implementation is structured into three conceptual stages: //! //! ### 1. Type normalization and lowering +//! //! Rust types are converted into a language-independent representation //! (`ClangDiscTy`) that mirrors the type categories used by Clang when computing //! function pointer discriminators. This includes canonicalization such as //! treating all pointer-like types uniformly and mapping Rust constructs onto //! their closest C equivalents. +//! //! One notable exception is C `_Complex`. Rust has no corresponding native type, //! so there is no canonical Rust representation to map onto Clang's `_Complex` //! type category. Rather than infer one (for example, by treating `(f32, f32)` @@ -31,29 +35,40 @@ //! encoding. //! //! ### 2. Type encoding +//! //! The lowered representation is serialized into a byte stream using rules //! intended to match Clang's implementation in: //! `encodeTypeForFunctionPointerAuth`. The resulting encoding describes the //! function signature in a target-independent form suitable for hashing. //! //! ### 3. Discriminator hashing +//! //! The encoded byte stream is hashed using LLVM's stable SipHash-2-4 based //! discriminator algorithm. The implementation here is a direct translation //! of LLVM/Clang's logic and must remain bit-for-bit compatible. See: //! . //! Defined in `llvm_siphash.rs`. //! +//! In addition to computing discriminators for individual function pointer +//! types, this module can recursively walk Rust type layouts and produce a map +//! from byte offsets to discriminators for function pointer fields contained +//! within aggregates. +//! //! ## Module structure //! //! - High-level API //! - `FnPtrDiscriminatorSource` //! - `ptrauth_compute_fn_ptr_type_discriminator_for` //! - `ptrauth_clone_discriminated_schema_for` +//! - `ptrauth_collect_fn_ptr_discriminators` //! //! - Low-level API //! - `FnPtrTypeDiscriminatorInput` //! - `compute_fn_ptr_type_discriminator` //! +//! - Layout traversal +//! - `ptrauth_collect_fn_ptr_discriminators` +//! //! - Signature extraction //! - `extract_fn_ptr_type` //! @@ -68,14 +83,16 @@ //! //! ## Compatibility requirements //! -//! Any changes to the encoding or hashing logic should be validated against Clang's -//! discriminator computation. Divergence from Clang will result in incompatible -//! pointer authentication values across language boundaries. +//! Any changes to the encoding or hashing logic should be validated against +//! Clang's discriminator computation. Divergence from Clang will result in +//! incompatible pointer authentication values across language boundaries. //! -//! This implementation intentionally approximates Clang's behavior for extern "C" -//! function types only. It does NOT attempt to model full type system rules. +//! This implementation intentionally approximates Clang's behavior for +//! `extern "C"` and `extern "System"` function types only. It does NOT attempt +//! to model full Rust type system rules. -use rustc_abi::ExternAbi; +use rustc_abi::{ExternAbi, Size}; +use rustc_data_structures::fx::FxHashMap; use rustc_middle::ty::{self, Instance, Ty, TyCtxt, Unnormalized}; use rustc_session::PointerAuthSchema; use rustc_span::sym; @@ -255,6 +272,129 @@ fn extract_fn_ptr_type<'tcx>(tcx: TyCtxt<'tcx>, mut ty: Ty<'tcx>) -> Option( + tcx: TyCtxt<'tcx>, + typing_env: ty::TypingEnv<'tcx>, + ty: Ty<'tcx>, +) -> FxHashMap { + let mut map = FxHashMap::default(); + + collect_fn_ptr_discriminators_inner(tcx, typing_env, ty, Size::ZERO, &mut map); + + map +} + +fn collect_fn_ptr_discriminators_inner<'tcx>( + tcx: TyCtxt<'tcx>, + typing_env: ty::TypingEnv<'tcx>, + ty: Ty<'tcx>, + base_offset: Size, + map: &mut FxHashMap, +) { + // Direct function pointer. + if let Some(disc) = ptrauth_compute_fn_ptr_type_discriminator_for(tcx, ty) { + map.insert(base_offset, disc.into()); + + return; + } + + match ty.kind() { + ty::Ref(_, pointee, _) => { + collect_fn_ptr_discriminators_inner(tcx, typing_env, *pointee, base_offset, map); + } + ty::Adt(def, args) if def.is_struct() => { + let Ok(layout) = tcx.layout_of(typing_env.as_query_input(ty)) else { + return; + }; + + let variant = def.non_enum_variant(); + + for (idx, field_def) in variant.fields.iter_enumerated() { + let field_ty = tcx.normalize_erasing_regions(typing_env, field_def.ty(tcx, args)); + + let field_offset = layout.fields.offset(idx.into()); + + collect_fn_ptr_discriminators_inner( + tcx, + typing_env, + field_ty, + base_offset + field_offset, + map, + ); + } + } + ty::Tuple(fields) => { + let Ok(layout) = tcx.layout_of(typing_env.as_query_input(ty)) else { + return; + }; + + for (idx, field_ty) in fields.iter().enumerate() { + let field_offset = layout.fields.offset(idx); + + collect_fn_ptr_discriminators_inner( + tcx, + typing_env, + field_ty, + base_offset + field_offset, + map, + ); + } + } + ty::Array(elem_ty, len) => { + let count = match len.try_to_target_usize(tcx) { + Some(v) => v, + None => return, + }; + + let Ok(elem_layout) = tcx.layout_of(typing_env.as_query_input(*elem_ty)) else { + return; + }; + + let stride = elem_layout.size; + + // Collect discriminator of one element, so we don't have to recompute it for all the + // elements in the array. + let mut elem_map = FxHashMap::default(); + + collect_fn_ptr_discriminators_inner( + tcx, + typing_env, + *elem_ty, + Size::ZERO, + &mut elem_map, + ); + + // SAFETY: We immediately collect into a Vec and sort by offset. + // The HashMap iteration order is irrelevant and must not affect determinism. + #[allow(rustc::potential_query_instability)] + let mut entries: Vec<(Size, u64)> = elem_map.into_iter().collect(); + entries.sort_unstable_by_key(|(offset, _)| *offset); + + // Replicate for every array slot. + for i in 0..count { + let elem_base = base_offset + stride * i; + + for (inner_offset, discr) in entries.iter().copied() { + map.insert(elem_base + inner_offset, discr); + } + } + } + _ => {} + } +} + /// Computes the Clang-compatible function pointer type discriminator. /// /// This is the low-level discriminator computation routine operating on an diff --git a/compiler/rustc_middle/src/ptrauth/mod.rs b/compiler/rustc_middle/src/ptrauth/mod.rs index 0eeef5e07f61c..46b3068524be7 100644 --- a/compiler/rustc_middle/src/ptrauth/mod.rs +++ b/compiler/rustc_middle/src/ptrauth/mod.rs @@ -3,5 +3,5 @@ pub mod llvm_siphash; pub use discriminator::{ FnPtrDiscriminatorSource, FnPtrTypeDiscriminatorInput, ptrauth_clone_discriminated_schema_for, - ptrauth_compute_fn_ptr_type_discriminator_for, + ptrauth_collect_fn_ptr_discriminators, ptrauth_compute_fn_ptr_type_discriminator_for, }; diff --git a/compiler/rustc_middle/src/ty/vtable.rs b/compiler/rustc_middle/src/ty/vtable.rs index fb56bda7d4562..95176361eac3e 100644 --- a/compiler/rustc_middle/src/ty/vtable.rs +++ b/compiler/rustc_middle/src/ty/vtable.rs @@ -85,6 +85,27 @@ pub(super) fn vtable_allocation_provider<'tcx>( tcx: TyCtxt<'tcx>, key: (Ty<'tcx>, Option>), ) -> AllocId { + let ptrauth_assert_not_c_abi_fn_ptr = |instance: ty::Instance<'tcx>| { + if tcx.sess.pointer_authentication_fn_ptr_type_discrimination() { + let sig = tcx + .instantiate_and_normalize_erasing_regions( + instance.args, + ty::TypingEnv::fully_monomorphized(), + tcx.fn_sig(instance.def_id()), + ) + .skip_binder(); + + assert!( + !matches!( + sig.abi(), + rustc_abi::ExternAbi::C { .. } | rustc_abi::ExternAbi::System { .. } + ), + "vtable entry unexpectedly has a C ABI function pointer type: {:?}", + instance + ); + } + }; + let (ty, poly_trait_ref) = key; let vtable_entries = if let Some(poly_trait_ref) = poly_trait_ref { @@ -123,6 +144,7 @@ pub(super) fn vtable_allocation_provider<'tcx>( VtblEntry::MetadataDropInPlace => { if ty.needs_drop(tcx, ty::TypingEnv::fully_monomorphized()) { let instance = ty::Instance::resolve_drop_glue(tcx, ty); + ptrauth_assert_not_c_abi_fn_ptr(instance); let fn_alloc_id = tcx.reserve_and_set_fn_alloc(instance, CTFE_ALLOC_SALT); let fn_ptr = Pointer::from(fn_alloc_id); Scalar::from_pointer(fn_ptr, &tcx) @@ -134,6 +156,7 @@ pub(super) fn vtable_allocation_provider<'tcx>( VtblEntry::MetadataAlign => Scalar::from_uint(align, ptr_size), VtblEntry::Vacant => continue, VtblEntry::Method(instance) => { + ptrauth_assert_not_c_abi_fn_ptr(instance); // Prepare the fn ptr we write into the vtable. let fn_alloc_id = tcx.reserve_and_set_fn_alloc(instance, CTFE_ALLOC_SALT); let fn_ptr = Pointer::from(fn_alloc_id);