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Auto merge of #123106 - maurer:cfi-closures, r=compiler-errors

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CFI: Abstract Closures and Coroutines

This will abstract coroutines in a moment, it's just abstracting closures for now to show `@rcvalle`

This uses the same principal as the methods on traits - figure out the `dyn` type representing the fn trait, instantiate it, and attach that alias set. We're essentially just computing how we would be called in a dynamic context, and attaching that.
This commit is contained in:
bors 2024-03-30 17:56:26 +00:00
commit 70714e38f2
5 changed files with 241 additions and 59 deletions
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131
compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
View File

@ -10,6 +10,7 @@
use rustc_data_structures::base_n;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir as hir;
use rustc_hir::lang_items::LangItem;
use rustc_middle::ty::layout::IntegerExt;
use rustc_middle::ty::TypeVisitableExt;
use rustc_middle::ty::{
@ -641,9 +642,7 @@ fn encode_ty<'tcx>(
}
// Function types
ty::FnDef(def_id, args)
| ty::Closure(def_id, args)
| ty::CoroutineClosure(def_id, args) => {
ty::FnDef(def_id, args) | ty::Closure(def_id, args) => {
// u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>,
// as vendor extended type.
let mut s = String::new();
@ -654,6 +653,18 @@ fn encode_ty<'tcx>(
typeid.push_str(&s);
}
ty::CoroutineClosure(def_id, args) => {
// u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>,
// as vendor extended type.
let mut s = String::new();
let name = encode_ty_name(tcx, *def_id);
let _ = write!(s, "u{}{}", name.len(), &name);
let parent_args = tcx.mk_args(args.as_coroutine_closure().parent_args());
s.push_str(&encode_args(tcx, parent_args, dict, options));
compress(dict, DictKey::Ty(ty, TyQ::None), &mut s);
typeid.push_str(&s);
}
ty::Coroutine(def_id, args, ..) => {
// u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>,
// as vendor extended type.
@ -1151,43 +1162,91 @@ pub fn typeid_for_instance<'tcx>(
};
let stripped_ty = strip_receiver_auto(tcx, upcast_ty);
instance.args = tcx.mk_args_trait(stripped_ty, instance.args.into_iter().skip(1));
} else if let ty::InstanceDef::VTableShim(def_id) = instance.def
&& let Some(trait_id) = tcx.trait_of_item(def_id)
{
// VTableShims may have a trait method, but a concrete Self. This is not suitable for a vtable,
// as the caller will not know the concrete Self.
let trait_ref = ty::TraitRef::new(tcx, trait_id, instance.args);
let invoke_ty = trait_object_ty(tcx, ty::Binder::dummy(trait_ref));
instance.args = tcx.mk_args_trait(invoke_ty, trait_ref.args.into_iter().skip(1));
}
if !options.contains(EncodeTyOptions::NO_SELF_TYPE_ERASURE)
&& let Some(impl_id) = tcx.impl_of_method(instance.def_id())
&& let Some(trait_ref) = tcx.impl_trait_ref(impl_id)
{
let impl_method = tcx.associated_item(instance.def_id());
let method_id = impl_method
.trait_item_def_id
.expect("Part of a trait implementation, but not linked to the def_id?");
let trait_method = tcx.associated_item(method_id);
let trait_id = trait_ref.skip_binder().def_id;
if traits::is_vtable_safe_method(tcx, trait_id, trait_method)
&& tcx.object_safety_violations(trait_id).is_empty()
if !options.contains(EncodeTyOptions::NO_SELF_TYPE_ERASURE) {
if let Some(impl_id) = tcx.impl_of_method(instance.def_id())
&& let Some(trait_ref) = tcx.impl_trait_ref(impl_id)
{
// Trait methods will have a Self polymorphic parameter, where the concreteized
// implementatation will not. We need to walk back to the more general trait method
let trait_ref = tcx.instantiate_and_normalize_erasing_regions(
instance.args,
ty::ParamEnv::reveal_all(),
trait_ref,
);
let invoke_ty = trait_object_ty(tcx, ty::Binder::dummy(trait_ref));
let impl_method = tcx.associated_item(instance.def_id());
let method_id = impl_method
.trait_item_def_id
.expect("Part of a trait implementation, but not linked to the def_id?");
let trait_method = tcx.associated_item(method_id);
let trait_id = trait_ref.skip_binder().def_id;
if traits::is_vtable_safe_method(tcx, trait_id, trait_method)
&& tcx.object_safety_violations(trait_id).is_empty()
{
// Trait methods will have a Self polymorphic parameter, where the concreteized
// implementatation will not. We need to walk back to the more general trait method
let trait_ref = tcx.instantiate_and_normalize_erasing_regions(
instance.args,
ty::ParamEnv::reveal_all(),
trait_ref,
);
let invoke_ty = trait_object_ty(tcx, ty::Binder::dummy(trait_ref));
// At the call site, any call to this concrete function through a vtable will be
// `Virtual(method_id, idx)` with appropriate arguments for the method. Since we have the
// original method id, and we've recovered the trait arguments, we can make the callee
// instance we're computing the alias set for match the caller instance.
//
// Right now, our code ignores the vtable index everywhere, so we use 0 as a placeholder.
// If we ever *do* start encoding the vtable index, we will need to generate an alias set
// based on which vtables we are putting this method into, as there will be more than one
// index value when supertraits are involved.
instance.def = ty::InstanceDef::Virtual(method_id, 0);
let abstract_trait_args =
tcx.mk_args_trait(invoke_ty, trait_ref.args.into_iter().skip(1));
instance.args = instance.args.rebase_onto(tcx, impl_id, abstract_trait_args);
// At the call site, any call to this concrete function through a vtable will be
// `Virtual(method_id, idx)` with appropriate arguments for the method. Since we have the
// original method id, and we've recovered the trait arguments, we can make the callee
// instance we're computing the alias set for match the caller instance.
//
// Right now, our code ignores the vtable index everywhere, so we use 0 as a placeholder.
// If we ever *do* start encoding the vtable index, we will need to generate an alias set
// based on which vtables we are putting this method into, as there will be more than one
// index value when supertraits are involved.
instance.def = ty::InstanceDef::Virtual(method_id, 0);
let abstract_trait_args =
tcx.mk_args_trait(invoke_ty, trait_ref.args.into_iter().skip(1));
instance.args = instance.args.rebase_onto(tcx, impl_id, abstract_trait_args);
}
} else if tcx.is_closure_like(instance.def_id()) {
// We're either a closure or a coroutine. Our goal is to find the trait we're defined on,
// instantiate it, and take the type of its only method as our own.
let closure_ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
let (trait_id, inputs) = match closure_ty.kind() {
ty::Closure(..) => {
let closure_args = instance.args.as_closure();
let trait_id = tcx.fn_trait_kind_to_def_id(closure_args.kind()).unwrap();
let tuple_args =
tcx.instantiate_bound_regions_with_erased(closure_args.sig()).inputs()[0];
(trait_id, tuple_args)
}
ty::Coroutine(..) => (
tcx.require_lang_item(LangItem::Coroutine, None),
instance.args.as_coroutine().resume_ty(),
),
ty::CoroutineClosure(..) => (
tcx.require_lang_item(LangItem::FnOnce, None),
tcx.instantiate_bound_regions_with_erased(
instance.args.as_coroutine_closure().coroutine_closure_sig(),
)
.tupled_inputs_ty,
),
x => bug!("Unexpected type kind for closure-like: {x:?}"),
};
let trait_ref = ty::TraitRef::new(tcx, trait_id, [closure_ty, inputs]);
let invoke_ty = trait_object_ty(tcx, ty::Binder::dummy(trait_ref));
let abstract_args = tcx.mk_args_trait(invoke_ty, trait_ref.args.into_iter().skip(1));
// There should be exactly one method on this trait, and it should be the one we're
// defining.
let call = tcx
.associated_items(trait_id)
.in_definition_order()
.find(|it| it.kind == ty::AssocKind::Fn)
.expect("No call-family function on closure-like Fn trait?")
.def_id;
instance.def = ty::InstanceDef::Virtual(call, 0);
instance.args = abstract_args;
}
}

33
tests/ui/sanitizer/cfi-async-closures.rs Normal file
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@ -0,0 +1,33 @@
// Check various forms of dynamic closure calls
//@ edition: 2021
//@ revisions: cfi kcfi
// FIXME(#122848) Remove only-linux once OSX CFI binaries work
//@ only-linux
//@ [cfi] needs-sanitizer-cfi
//@ [kcfi] needs-sanitizer-kcfi
//@ compile-flags: -C target-feature=-crt-static
//@ [cfi] compile-flags: -C codegen-units=1 -C lto -C prefer-dynamic=off -C opt-level=0
//@ [cfi] compile-flags: -Z sanitizer=cfi
//@ [kcfi] compile-flags: -Z sanitizer=kcfi
//@ [kcfi] compile-flags: -C panic=abort -Z panic-abort-tests -C prefer-dynamic=off
//@ run-pass
#![feature(async_closure)]
#![feature(async_fn_traits)]
use std::ops::AsyncFn;
#[inline(never)]
fn identity<T>(x: T) -> T { x }
// We can't actually create a `dyn AsyncFn()`, because it's not object-safe, but we should check
// that we don't bug out when we encounter one.
fn main() {
let f = identity(async || ());
let _ = f.async_call(());
let _ = f();
let g: Box<dyn FnOnce() -> _> = Box::new(f) as _;
let _ = g();
}

23
tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs
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@ -1,23 +0,0 @@
// Tests that converting a closure to a function pointer works
// The notable thing being tested here is that when the closure does not capture anything,
// the call method from its Fn trait takes a ZST representing its environment. The compiler then
// uses the assumption that the ZST is non-passed to reify this into a function pointer.
//
// This checks that the reified function pointer will have the expected alias set at its call-site.
//@ revisions: cfi kcfi
// FIXME(#122848) Remove only-linux once OSX CFI binaries work
//@ only-linux
//@ [cfi] needs-sanitizer-cfi
//@ [kcfi] needs-sanitizer-kcfi
//@ compile-flags: -C target-feature=-crt-static
//@ [cfi] compile-flags: -C codegen-units=1 -C lto -C prefer-dynamic=off -C opt-level=0
//@ [cfi] compile-flags: -Z sanitizer=cfi
//@ [kcfi] compile-flags: -Z sanitizer=kcfi
//@ [kcfi] compile-flags: -C panic=abort -C prefer-dynamic=off
//@ run-pass
pub fn main() {
let f: &fn() = &((|| ()) as _);
f();
}

83
tests/ui/sanitizer/cfi-closures.rs Normal file
View File

@ -0,0 +1,83 @@
// Check various forms of dynamic closure calls
//@ revisions: cfi kcfi
// FIXME(#122848) Remove only-linux once OSX CFI binaries work
//@ only-linux
//@ [cfi] needs-sanitizer-cfi
//@ [kcfi] needs-sanitizer-kcfi
//@ compile-flags: -C target-feature=-crt-static
//@ [cfi] compile-flags: -C codegen-units=1 -C lto -C prefer-dynamic=off -C opt-level=0
//@ [cfi] compile-flags: -Z sanitizer=cfi
//@ [kcfi] compile-flags: -Z sanitizer=kcfi
//@ [kcfi] compile-flags: -C panic=abort -Z panic-abort-tests -C prefer-dynamic=off
//@ compile-flags: --test
//@ run-pass
#![feature(fn_traits)]
#![feature(unboxed_closures)]
#![feature(cfg_sanitize)]
fn foo<'a, T>() -> Box<dyn Fn(&'a T) -> &'a T> {
Box::new(|x| x)
}
#[test]
fn dyn_fn_with_params() {
let x = 3;
let f = foo();
f(&x);
// FIXME remove once drops are working.
std::mem::forget(f);
}
#[test]
fn call_fn_trait() {
let f: &(dyn Fn()) = &(|| {}) as _;
f.call(());
}
#[test]
fn fn_ptr_cast() {
let f: &fn() = &((|| ()) as _);
f();
}
fn use_fnmut<F: FnMut()>(mut f: F) {
f()
}
#[test]
fn fn_to_fnmut() {
let f: &(dyn Fn()) = &(|| {}) as _;
use_fnmut(f);
}
fn hrtb_helper(f: &dyn for<'a> Fn(&'a usize)) {
f(&10)
}
#[test]
fn hrtb_fn() {
hrtb_helper((&|x: &usize| println!("{}", *x)) as _)
}
#[test]
fn fnonce() {
let f: Box<dyn FnOnce()> = Box::new(|| {}) as _;
f();
}
fn use_closure<C>(call: extern "rust-call" fn(&C, ()) -> i32, f: &C) -> i32 {
call(f, ())
}
#[test]
// FIXME after KCFI reify support is added, remove this
// It will appear to work if you test locally, set -C opt-level=0 to see it fail.
#[cfg_attr(sanitize = "kcfi", ignore)]
fn closure_addr_taken() {
let x = 3i32;
let f = || x;
let call = Fn::<()>::call;
use_closure(call, &f);
}

30
tests/ui/sanitizer/cfi-coroutine.rs Normal file
View File

@ -0,0 +1,30 @@
// Verifies that we can call dynamic coroutines
//@ revisions: cfi kcfi
// FIXME(#122848) Remove only-linux once OSX CFI binaries work
//@ only-linux
//@ [cfi] needs-sanitizer-cfi
//@ [kcfi] needs-sanitizer-kcfi
//@ compile-flags: -C target-feature=-crt-static
//@ [cfi] compile-flags: -C codegen-units=1 -C lto -C prefer-dynamic=off -C opt-level=0
//@ [cfi] compile-flags: -Z sanitizer=cfi
//@ [kcfi] compile-flags: -Z sanitizer=kcfi
//@ [kcfi] compile-flags: -C panic=abort -Z panic-abort-tests -C prefer-dynamic=off
//@ compile-flags: --test
//@ run-pass
#![feature(coroutines)]
#![feature(coroutine_trait)]
use std::ops::{Coroutine, CoroutineState};
use std::pin::{pin, Pin};
fn main() {
let mut coro = |x: i32| {
yield x;
"done"
};
let mut abstract_coro: Pin<&mut dyn Coroutine<i32,Yield=i32,Return=&'static str>> = pin!(coro);
assert_eq!(abstract_coro.as_mut().resume(2), CoroutineState::Yielded(2));
assert_eq!(abstract_coro.as_mut().resume(0), CoroutineState::Complete("done"));
}