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remove move_val_init leftovers

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This commit is contained in:
Ralf Jung 2020-12-30 20:09:26 +01:00
parent 1862135351
commit db03b58f23
10 changed files with 32 additions and 394 deletions
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8
compiler/rustc_mir/src/transform/check_unsafety.rs
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@ -223,13 +223,6 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
// Check for raw pointer `Deref`.
for (base, proj) in place.iter_projections() {
if proj == ProjectionElem::Deref {
let source_info = self.source_info; // Backup source_info so we can restore it later.
if base.projection.is_empty() && decl.internal {
// Internal locals are used in the `move_val_init` desugaring.
// We want to check unsafety against the source info of the
// desugaring, rather than the source info of the RHS.
self.source_info = self.body.local_decls[place.local].source_info;
}
let base_ty = base.ty(self.body, self.tcx).ty;
if base_ty.is_unsafe_ptr() {
self.require_unsafe(
@ -237,7 +230,6 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
UnsafetyViolationDetails::DerefOfRawPointer,
)
}
self.source_info = source_info; // Restore backed-up source_info.
}
}

44
compiler/rustc_mir_build/src/build/expr/into.rs
View File

@ -10,9 +10,7 @@ use rustc_data_structures::stack::ensure_sufficient_stack;
use rustc_hir as hir;
use rustc_middle::middle::region;
use rustc_middle::mir::*;
use rustc_middle::ty::{self, CanonicalUserTypeAnnotation};
use rustc_span::symbol::sym;
use rustc_target::spec::abi::Abi;
use rustc_middle::ty::{CanonicalUserTypeAnnotation};
use std::slice;
@ -185,45 +183,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
},
)
}
ExprKind::Call { ty, fun, args, from_hir_call, fn_span } => {
let intrinsic = match *ty.kind() {
ty::FnDef(def_id, _) => {
let f = ty.fn_sig(this.hir.tcx());
if f.abi() == Abi::RustIntrinsic || f.abi() == Abi::PlatformIntrinsic {
Some(this.hir.tcx().item_name(def_id))
} else {
None
}
}
_ => None,
};
ExprKind::Call { ty: _, fun, args, from_hir_call, fn_span } => {
let fun = unpack!(block = this.as_local_operand(block, fun));
if let Some(sym::move_val_init) = intrinsic {
// `move_val_init` has "magic" semantics - the second argument is
// always evaluated "directly" into the first one.
let mut args = args.into_iter();
let ptr = args.next().expect("0 arguments to `move_val_init`");
let val = args.next().expect("1 argument to `move_val_init`");
assert!(args.next().is_none(), ">2 arguments to `move_val_init`");
let ptr = this.hir.mirror(ptr);
let ptr_ty = ptr.ty;
// Create an *internal* temp for the pointer, so that unsafety
// checking won't complain about the raw pointer assignment.
let ptr_temp = this
.local_decls
.push(LocalDecl::with_source_info(ptr_ty, source_info).internal());
let ptr_temp = Place::from(ptr_temp);
// No need for a scope, ptr_temp doesn't need drop
let block = unpack!(this.into(ptr_temp, None, block, ptr));
// Maybe we should provide a scope here so that
// `move_val_init` wouldn't leak on panic even with an
// arbitrary `val` expression, but `schedule_drop`,
// borrowck and drop elaboration all prevent us from
// dropping `ptr_temp.deref()`.
this.into(this.hir.tcx().mk_place_deref(ptr_temp), None, block, val)
} else {
let args: Vec<_> = args
.into_iter()
.map(|arg| unpack!(block = this.as_local_call_operand(block, arg)))
@ -258,7 +219,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
schedule_drop(this);
success.unit()
}
}
ExprKind::Use { source } => this.into(destination, scope, block, source),
ExprKind::Borrow { arg, borrow_kind } => {
// We don't do this in `as_rvalue` because we use `as_place`

1
compiler/rustc_span/src/symbol.rs
View File

@ -713,7 +713,6 @@ symbols! {
more_struct_aliases,
movbe_target_feature,
move_ref_pattern,
move_val_init,
mul,
mul_assign,
mul_with_overflow,

1
compiler/rustc_typeck/src/check/intrinsic.rs
View File

@ -159,7 +159,6 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
}
sym::forget => (1, vec![param(0)], tcx.mk_unit()),
sym::transmute => (2, vec![param(0)], param(1)),
sym::move_val_init => (1, vec![tcx.mk_mut_ptr(param(0)), param(0)], tcx.mk_unit()),
sym::prefetch_read_data
| sym::prefetch_write_data
| sym::prefetch_read_instruction

19
src/test/codegen/intrinsics/move-val-init.rs
View File

@ -1,19 +0,0 @@
// compile-flags: -C no-prepopulate-passes
#![feature(core_intrinsics)]
#![crate_type = "lib"]
// test that `move_val_init` actually avoids big allocas
use std::intrinsics::move_val_init;
pub struct Big {
pub data: [u8; 65536]
}
// CHECK-LABEL: @test_mvi
#[no_mangle]
pub unsafe fn test_mvi(target: *mut Big, make_big: fn() -> Big) {
// CHECK: call void %make_big(%Big*{{[^%]*}} %target)
move_val_init(target, make_big());
}

191
src/test/ui/intrinsics/intrinsic-move-val-cleanups.rs
View File

@ -1,191 +0,0 @@
// run-pass
#![allow(unused_braces)]
#![allow(unused_unsafe)]
#![allow(unreachable_code)]
// ignore-emscripten no threads support
#![allow(stable_features)]
// This test is checking that the move_val_init intrinsic is
// respecting cleanups for both of its argument expressions.
//
// In other words, if either DEST or SOURCE in
//
// `intrinsics::move_val_init(DEST, SOURCE)
//
// introduce temporaries that require cleanup, and SOURCE panics, then
// make sure the cleanups still occur.
#![feature(core_intrinsics, sync_poison)]
use std::cell::RefCell;
use std::intrinsics;
use std::sync::{Arc, LockResult, Mutex, MutexGuard};
use std::thread;
type LogEntry = (&'static str, i32);
type Guarded = RefCell<Vec<LogEntry>>;
#[derive(Clone)]
struct Log(Arc<Mutex<Guarded>>);
struct Acquired<'a>(MutexGuard<'a, Guarded>);
type LogState = (MutexWas, &'static [LogEntry]);
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
enum MutexWas { Poisoned, NotPoisoned }
impl Log {
fn lock(&self) -> LockResult<MutexGuard<RefCell<Vec<LogEntry>>>> { self.0.lock() }
fn acquire(&self) -> Acquired { Acquired(self.0.lock().unwrap()) }
}
impl<'a> Acquired<'a> {
fn log(&self, s: &'static str, i: i32) { self.0.borrow_mut().push((s, i)); }
}
const TEST1_EXPECT: LogState = (MutexWas::NotPoisoned,
&[("double-check non-poisoning path", 1)
]);
fn test1(log: Log) {
{
let acq = log.acquire();
acq.log("double-check non-poisoning path", 1);
}
panic!("every test ends in a panic");
}
const TEST2_EXPECT: LogState = (MutexWas::Poisoned,
&[("double-check poisoning path", 1),
("and multiple log entries", 2),
]);
fn test2(log: Log) {
let acq = log.acquire();
acq.log("double-check poisoning path", 1);
acq.log("and multiple log entries", 2);
panic!("every test ends in a panic");
}
struct LogOnDrop<'a>(&'a Acquired<'a>, &'static str, i32);
impl<'a> Drop for LogOnDrop<'a> {
fn drop(&mut self) {
self.0.log(self.1, self.2);
}
}
const TEST3_EXPECT: LogState = (MutexWas::Poisoned,
&[("double-check destructors can log", 1),
("drop d2", 2),
("drop d1", 3),
]);
fn test3(log: Log) {
let acq = log.acquire();
acq.log("double-check destructors can log", 1);
let _d1 = LogOnDrop(&acq, "drop d1", 3);
let _d2 = LogOnDrop(&acq, "drop d2", 2);
panic!("every test ends in a panic");
}
// The *real* tests of panic-handling for move_val_init intrinsic
// start here.
const TEST4_EXPECT: LogState = (MutexWas::Poisoned,
&[("neither arg panics", 1),
("drop temp LOD", 2),
("drop temp LOD", 3),
("drop dest_b", 4),
("drop dest_a", 5),
]);
fn test4(log: Log) {
let acq = log.acquire();
acq.log("neither arg panics", 1);
let mut dest_a = LogOnDrop(&acq, "a will be overwritten, not dropped", 0);
let mut dest_b = LogOnDrop(&acq, "b will be overwritten, not dropped", 0);
unsafe {
intrinsics::move_val_init({ LogOnDrop(&acq, "drop temp LOD", 2); &mut dest_a },
LogOnDrop(&acq, "drop dest_a", 5));
intrinsics::move_val_init(&mut dest_b, { LogOnDrop(&acq, "drop temp LOD", 3);
LogOnDrop(&acq, "drop dest_b", 4) });
}
panic!("every test ends in a panic");
}
// Check that move_val_init(PANIC, SOURCE_EXPR) never evaluates SOURCE_EXPR
const TEST5_EXPECT: LogState = (MutexWas::Poisoned,
&[("first arg panics", 1),
("drop orig dest_a", 2),
]);
fn test5(log: Log) {
let acq = log.acquire();
acq.log("first arg panics", 1);
let mut _dest_a = LogOnDrop(&acq, "drop orig dest_a", 2);
unsafe {
intrinsics::move_val_init({ panic!("every test ends in a panic") },
LogOnDrop(&acq, "we never get here", 0));
}
}
// Check that move_val_init(DEST_EXPR, PANIC) cleans up temps from DEST_EXPR.
const TEST6_EXPECT: LogState = (MutexWas::Poisoned,
&[("second arg panics", 1),
("drop temp LOD", 2),
("drop orig dest_a", 3),
]);
fn test6(log: Log) {
let acq = log.acquire();
acq.log("second arg panics", 1);
let mut dest_a = LogOnDrop(&acq, "drop orig dest_a", 3);
unsafe {
intrinsics::move_val_init({ LogOnDrop(&acq, "drop temp LOD", 2); &mut dest_a },
{ panic!("every test ends in a panic"); });
}
}
// Check that move_val_init(DEST_EXPR, COMPLEX_PANIC) cleans up temps from COMPLEX_PANIC.
const TEST7_EXPECT: LogState = (MutexWas::Poisoned,
&[("second arg panics", 1),
("drop temp LOD", 2),
("drop temp LOD", 3),
("drop orig dest_a", 4),
]);
fn test7(log: Log) {
let acq = log.acquire();
acq.log("second arg panics", 1);
let mut dest_a = LogOnDrop(&acq, "drop orig dest_a", 4);
unsafe {
intrinsics::move_val_init({ LogOnDrop(&acq, "drop temp LOD", 2); &mut dest_a },
{ LogOnDrop(&acq, "drop temp LOD", 3);
panic!("every test ends in a panic"); });
}
}
const TEST_SUITE: &'static [(&'static str, fn (Log), LogState)] =
&[("test1", test1, TEST1_EXPECT),
("test2", test2, TEST2_EXPECT),
("test3", test3, TEST3_EXPECT),
("test4", test4, TEST4_EXPECT),
("test5", test5, TEST5_EXPECT),
("test6", test6, TEST6_EXPECT),
("test7", test7, TEST7_EXPECT),
];
fn main() {
for &(name, test, expect) in TEST_SUITE {
let log = Log(Arc::new(Mutex::new(RefCell::new(Vec::new()))));
let ret = { let log = log.clone(); thread::spawn(move || test(log)).join() };
assert!(ret.is_err(), "{} must end with panic", name);
{
let l = log.lock();
match l {
Ok(acq) => {
assert_eq!((MutexWas::NotPoisoned, &acq.borrow()[..]), expect);
println!("{} (unpoisoned) log: {:?}", name, *acq);
}
Err(e) => {
let acq = e.into_inner();
assert_eq!((MutexWas::Poisoned, &acq.borrow()[..]), expect);
println!("{} (poisoned) log: {:?}", name, *acq);
}
}
}
}
}

81
src/test/ui/intrinsics/intrinsic-move-val.rs
View File

@ -1,81 +0,0 @@
// run-pass
#![feature(box_syntax)]
#![feature(intrinsics)]
mod rusti {
extern "rust-intrinsic" {
pub fn move_val_init<T>(dst: *mut T, src: T);
}
}
pub fn main() {
unsafe {
// sanity check
check_drops_state(0, None);
let mut x: Option<Box<D>> = Some(box D(1));
assert_eq!(x.as_ref().unwrap().0, 1);
// A normal overwrite, to demonstrate `check_drops_state`.
x = Some(box D(2));
// At this point, one destructor has run, because the
// overwrite of `x` drops its initial value.
check_drops_state(1, Some(1));
let mut y: Option<Box<D>> = std::mem::zeroed();
// An initial binding does not overwrite anything.
check_drops_state(1, Some(1));
// Since `y` has been initialized via the `init` intrinsic, it
// would be unsound to directly overwrite its value via normal
// assignment.
//
// The code currently generated by the compiler is overly
// accepting, however, in that it will check if `y` is itself
// null and thus avoid the unsound action of attempting to
// free null. In other words, if we were to do a normal
// assignment like `y = box D(4);` here, it probably would not
// crash today. But the plan is that it may well crash in the
// future, (I believe).
// `x` is moved here; the manner in which this is tracked by the
// compiler is hidden.
rusti::move_val_init(&mut y, x);
// But what we *can* observe is how many times the destructor
// for `D` is invoked, and what the last value we saw was
// during such a destructor call. We do so after the end of
// this scope.
assert_eq!(y.as_ref().unwrap().0, 2);
y.as_mut().unwrap().0 = 3;
assert_eq!(y.as_ref().unwrap().0, 3);
check_drops_state(1, Some(1));
}
check_drops_state(2, Some(3));
}
static mut NUM_DROPS: i32 = 0;
static mut LAST_DROPPED: Option<i32> = None;
fn check_drops_state(num_drops: i32, last_dropped: Option<i32>) {
unsafe {
assert_eq!(NUM_DROPS, num_drops);
assert_eq!(LAST_DROPPED, last_dropped);
}
}
struct D(i32);
impl Drop for D {
fn drop(&mut self) {
unsafe {
NUM_DROPS += 1;
LAST_DROPPED = Some(self.0);
}
}
}

4
src/test/ui/panic-handler/weak-lang-item.stderr
View File

@ -10,10 +10,10 @@ help: you can use `as` to change the binding name of the import
LL | extern crate core as other_core;
|
error: `#[panic_handler]` function required, but not found
error: language item required, but not found: `eh_personality`
error: `#[panic_handler]` function required, but not found
error: aborting due to 3 previous errors
For more information about this error, try `rustc --explain E0259`.

10
src/test/ui/unsafe/unsafe-move-val-init.rs
View File

@ -1,10 +0,0 @@
#![feature(core_intrinsics)]
use std::intrinsics;
// `move_val_init` has an odd desugaring, check that it is still treated
// as unsafe.
fn main() {
intrinsics::move_val_init(1 as *mut u32, 1);
//~^ ERROR dereference of raw pointer is unsafe
}

11
src/test/ui/unsafe/unsafe-move-val-init.stderr
View File

@ -1,11 +0,0 @@
error[E0133]: dereference of raw pointer is unsafe and requires unsafe function or block
--> $DIR/unsafe-move-val-init.rs:8:5
|
LL | intrinsics::move_val_init(1 as *mut u32, 1);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereference of raw pointer
|
= note: raw pointers may be NULL, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
error: aborting due to previous error
For more information about this error, try `rustc --explain E0133`.