mirror of
https://github.com/rust-lang/rust.git
synced 2024-12-12 08:36:03 +00:00
593 lines
16 KiB
Rust
593 lines
16 KiB
Rust
// unit-test: ReferencePropagation
|
|
// needs-unwind
|
|
|
|
#![feature(raw_ref_op)]
|
|
#![feature(core_intrinsics, custom_mir)]
|
|
|
|
#[inline(never)]
|
|
fn opaque(_: impl Sized) {}
|
|
|
|
fn reference_propagation<'a, T: Copy>(single: &'a T, mut multiple: &'a T) {
|
|
// Propagation through a reference.
|
|
{
|
|
let a = 5_usize;
|
|
let b = &a; // This borrow is only used once.
|
|
let c = *b; // This should be optimized.
|
|
opaque(()); // We use opaque to separate cases into basic blocks in the MIR.
|
|
}
|
|
|
|
// Propagation through a two references.
|
|
{
|
|
let a = 5_usize;
|
|
let a2 = 7_usize;
|
|
let mut b = &a;
|
|
b = &a2;
|
|
// `b` is assigned twice, so we cannot propagate it.
|
|
let c = *b;
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation through a borrowed reference.
|
|
{
|
|
let a = 5_usize;
|
|
let b = &a;
|
|
let d = &b;
|
|
let c = *b; // `b` is immutably borrowed, we know its value, but do not propagate it
|
|
opaque(d); // prevent `d` from being removed.
|
|
}
|
|
|
|
// Propagation through a borrowed reference.
|
|
{
|
|
let a = 5_usize;
|
|
let mut b = &a;
|
|
let d = &raw mut b;
|
|
let c = *b; // `b` is mutably borrowed, we cannot know its value.
|
|
opaque(d); // prevent `d` from being removed.
|
|
}
|
|
|
|
// Propagation through an escaping borrow.
|
|
{
|
|
let a = 7_usize;
|
|
let b = &a;
|
|
let c = *b;
|
|
opaque(b); // `b` escapes here, but we can still replace immutable borrow
|
|
}
|
|
|
|
// Propagation through a transitively escaping borrow.
|
|
{
|
|
let a = 7_usize;
|
|
let b1 = &a;
|
|
let c = *b1;
|
|
let b2 = b1;
|
|
let c2 = *b2;
|
|
let b3 = b2;
|
|
// `b3` escapes here, so we can only replace immutable borrow,
|
|
// for either `b`, `b2` or `b3`.
|
|
opaque(b3);
|
|
}
|
|
|
|
// Propagation a reborrow of an argument.
|
|
{
|
|
let a = &*single;
|
|
let b = *a; // This should be optimized as `*single`.
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation a reborrow of a mutated argument.
|
|
{
|
|
let a = &*multiple;
|
|
multiple = &*single;
|
|
let b = *a; // This should not be optimized.
|
|
opaque(());
|
|
}
|
|
|
|
// Fixed-point propagation through a borrowed reference.
|
|
{
|
|
let a = 5_usize;
|
|
let b = &a;
|
|
let d = &b; // first round promotes debuginfo for `d`
|
|
let c = *b; // second round propagates this dereference
|
|
opaque(());
|
|
}
|
|
|
|
// Fixed-point propagation through a borrowed reference.
|
|
{
|
|
let a = 5_usize;
|
|
let mut b = &a;
|
|
let d = &mut b; // first round promotes debuginfo for `d`
|
|
let c = *b; // second round propagates this dereference
|
|
opaque(());
|
|
}
|
|
}
|
|
|
|
fn reference_propagation_mut<'a, T: Copy>(single: &'a mut T, mut multiple: &'a mut T) {
|
|
// Propagation through a reference.
|
|
{
|
|
let mut a = 5_usize;
|
|
let b = &mut a; // This borrow is only used once.
|
|
let c = *b; // This should be optimized.
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation through a two references.
|
|
{
|
|
let mut a = 5_usize;
|
|
let mut a2 = 7_usize;
|
|
let mut b = &mut a;
|
|
b = &mut a2;
|
|
// `b` is assigned twice, so we cannot propagate it.
|
|
let c = *b;
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation through a borrowed reference.
|
|
{
|
|
let mut a = 5_usize;
|
|
let b = &mut a;
|
|
let d = &b;
|
|
let c = *b; // `b` is immutably borrowed, we know its value, but cannot be removed.
|
|
opaque(d); // prevent `d` from being removed.
|
|
}
|
|
|
|
// Propagation through a borrowed reference.
|
|
{
|
|
let mut a = 5_usize;
|
|
let mut b = &mut a;
|
|
let d = &raw mut b;
|
|
let c = *b; // `b` is mutably borrowed, we cannot know its value.
|
|
opaque(d); // prevent `d` from being removed.
|
|
}
|
|
|
|
// Propagation through an escaping borrow.
|
|
{
|
|
let mut a = 7_usize;
|
|
let b = &mut a;
|
|
let c = *b;
|
|
opaque(b); // `b` escapes here, so we can only replace immutable borrow
|
|
}
|
|
|
|
// Propagation through a transitively escaping borrow.
|
|
{
|
|
let mut a = 7_usize;
|
|
let b1 = &mut a;
|
|
let c = *b1;
|
|
let b2 = b1;
|
|
let c2 = *b2;
|
|
let b3 = b2;
|
|
// `b3` escapes here, so we can only replace immutable borrow,
|
|
// for either `b`, `b2` or `b3`.
|
|
opaque(b3);
|
|
}
|
|
|
|
// Propagation a reborrow of an argument.
|
|
{
|
|
let a = &mut *single;
|
|
let b = *a; // This should be optimized as `*single`.
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation a reborrow of a mutated argument.
|
|
{
|
|
let a = &mut *multiple;
|
|
multiple = &mut *single;
|
|
let b = *a; // This should not be optimized.
|
|
opaque(());
|
|
}
|
|
|
|
// Fixed-point propagation through a borrowed reference.
|
|
{
|
|
let mut a = 5_usize;
|
|
let b = &mut a;
|
|
let d = &b; // first round promotes debuginfo for `d`
|
|
let c = *b; // second round propagates this dereference
|
|
opaque(());
|
|
}
|
|
|
|
// Fixed-point propagation through a borrowed reference.
|
|
{
|
|
let mut a = 5_usize;
|
|
let mut b = &mut a;
|
|
let d = &mut b; // first round promotes debuginfo for `d`
|
|
let c = *b; // second round propagates this dereference
|
|
opaque(());
|
|
}
|
|
}
|
|
|
|
fn reference_propagation_const_ptr<T: Copy>(single: *const T, mut multiple: *const T) {
|
|
// Propagation through a reference.
|
|
unsafe {
|
|
let a = 5_usize;
|
|
let b = &raw const a; // This borrow is only used once.
|
|
let c = *b; // This should be optimized.
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation through a two references.
|
|
unsafe {
|
|
let a = 5_usize;
|
|
let a2 = 7_usize;
|
|
let mut b = &raw const a;
|
|
b = &raw const a2;
|
|
// `b` is assigned twice, so we cannot propagate it.
|
|
let c = *b;
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation through a borrowed reference.
|
|
unsafe {
|
|
let a = 5_usize;
|
|
let b = &raw const a;
|
|
let d = &b;
|
|
let c = *b; // `b` is immutably borrowed, we know its value, but cannot be removed.
|
|
opaque(d); // prevent `d` from being removed.
|
|
}
|
|
|
|
// Propagation through a borrowed reference.
|
|
unsafe {
|
|
let a = 5_usize;
|
|
let mut b = &raw const a;
|
|
let d = &raw mut b;
|
|
let c = *b; // `b` is mutably borrowed, we cannot know its value.
|
|
opaque(d); // prevent `d` from being removed.
|
|
}
|
|
|
|
// Propagation through an escaping borrow.
|
|
unsafe {
|
|
let a = 7_usize;
|
|
let b = &raw const a;
|
|
let c = *b;
|
|
opaque(b); // `b` escapes here, so we can only replace immutable borrow
|
|
}
|
|
|
|
// Propagation through a transitively escaping borrow.
|
|
unsafe {
|
|
let a = 7_usize;
|
|
let b1 = &raw const a;
|
|
let c = *b1;
|
|
let b2 = b1;
|
|
let c2 = *b2;
|
|
let b3 = b2;
|
|
// `b3` escapes here, so we can only replace immutable borrow,
|
|
// for either `b`, `b2` or `b3`.
|
|
opaque(b3);
|
|
}
|
|
|
|
// Propagation a reborrow of an argument.
|
|
unsafe {
|
|
let a = &raw const *single;
|
|
let b = *a; // This should be optimized as `*single`.
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation a reborrow of a mutated argument.
|
|
unsafe {
|
|
let a = &raw const *multiple;
|
|
multiple = &raw const *single;
|
|
let b = *a; // This should not be optimized.
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation through a reborrow.
|
|
unsafe {
|
|
let a = 13_usize;
|
|
let b = &raw const a;
|
|
let c = &raw const *b;
|
|
let e = *c;
|
|
opaque(());
|
|
}
|
|
|
|
// Fixed-point propagation through a borrowed reference.
|
|
unsafe {
|
|
let a = 5_usize;
|
|
let b = &raw const a;
|
|
let d = &b; // first round promotes debuginfo for `d`
|
|
let c = *b; // second round propagates this dereference
|
|
opaque(());
|
|
}
|
|
|
|
// Fixed-point propagation through a borrowed reference.
|
|
unsafe {
|
|
let a = 5_usize;
|
|
let mut b = &raw const a;
|
|
let d = &mut b; // first round promotes debuginfo for `d`
|
|
let c = *b; // second round propagates this dereference
|
|
opaque(());
|
|
}
|
|
}
|
|
|
|
fn reference_propagation_mut_ptr<T: Copy>(single: *mut T, mut multiple: *mut T) {
|
|
// Propagation through a reference.
|
|
unsafe {
|
|
let mut a = 5_usize;
|
|
let b = &raw mut a; // This borrow is only used once.
|
|
let c = *b; // This should be optimized.
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation through a two references.
|
|
unsafe {
|
|
let mut a = 5_usize;
|
|
let mut a2 = 7_usize;
|
|
let mut b = &raw mut a;
|
|
b = &raw mut a2;
|
|
// `b` is assigned twice, so we cannot propagate it.
|
|
let c = *b;
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation through a borrowed reference.
|
|
unsafe {
|
|
let mut a = 5_usize;
|
|
let b = &raw mut a;
|
|
let d = &b;
|
|
let c = *b; // `b` is immutably borrowed, we know its value, but cannot be removed.
|
|
opaque(d); // prevent `d` from being removed.
|
|
}
|
|
|
|
// Propagation through a borrowed reference.
|
|
unsafe {
|
|
let mut a = 5_usize;
|
|
let mut b = &raw mut a;
|
|
let d = &raw mut b;
|
|
let c = *b; // `b` is mutably borrowed, we cannot know its value.
|
|
opaque(d); // prevent `d` from being removed.
|
|
}
|
|
|
|
// Propagation through an escaping borrow.
|
|
unsafe {
|
|
let mut a = 7_usize;
|
|
let b = &raw mut a;
|
|
let c = *b;
|
|
opaque(b); // `b` escapes here, so we can only replace immutable borrow
|
|
}
|
|
|
|
// Propagation through a transitively escaping borrow.
|
|
unsafe {
|
|
let mut a = 7_usize;
|
|
let b1 = &raw mut a;
|
|
let c = *b1;
|
|
let b2 = b1;
|
|
let c2 = *b2;
|
|
let b3 = b2;
|
|
// `b3` escapes here, so we can only replace immutable borrow,
|
|
// for either `b`, `b2` or `b3`.
|
|
opaque(b3);
|
|
}
|
|
|
|
// Propagation a reborrow of an argument.
|
|
unsafe {
|
|
let a = &raw mut *single;
|
|
let b = *a; // This should be optimized as `*single`.
|
|
opaque(());
|
|
}
|
|
|
|
// Propagation a reborrow of a mutated argument.
|
|
unsafe {
|
|
let a = &raw mut *multiple;
|
|
multiple = &raw mut *single;
|
|
let b = *a; // This should not be optimized.
|
|
opaque(());
|
|
}
|
|
|
|
// Fixed-point propagation through a borrowed reference.
|
|
unsafe {
|
|
let mut a = 5_usize;
|
|
let b = &raw mut a;
|
|
let d = &b; // first round promotes debuginfo for `d`
|
|
let c = *b; // second round propagates this dereference
|
|
opaque(());
|
|
}
|
|
|
|
// Fixed-point propagation through a borrowed reference.
|
|
unsafe {
|
|
let mut a = 5_usize;
|
|
let mut b = &raw mut a;
|
|
let d = &mut b; // first round promotes debuginfo for `d`
|
|
let c = *b; // second round propagates this dereference
|
|
opaque(());
|
|
}
|
|
}
|
|
|
|
#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
|
|
fn read_through_raw(x: &mut usize) -> usize {
|
|
use std::intrinsics::mir::*;
|
|
|
|
mir!(
|
|
let r1: &mut usize;
|
|
let r2: &mut usize;
|
|
let p1: *mut usize;
|
|
let p2: *mut usize;
|
|
|
|
{
|
|
r1 = &mut *x;
|
|
r2 = &mut *r1;
|
|
p1 = &raw mut *r1;
|
|
p2 = &raw mut *r2;
|
|
|
|
RET = *p1;
|
|
RET = *p2;
|
|
Return()
|
|
}
|
|
)
|
|
}
|
|
|
|
#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
|
|
fn multiple_storage() {
|
|
use std::intrinsics::mir::*;
|
|
|
|
mir!(
|
|
let x: i32;
|
|
{
|
|
StorageLive(x);
|
|
x = 5;
|
|
let z = &x;
|
|
StorageDead(x);
|
|
StorageLive(x);
|
|
// As there are multiple `StorageLive` statements for `x`, we cannot know if this `z`'s
|
|
// pointer address is the address of `x`, so do nothing.
|
|
let y = *z;
|
|
Call(RET = opaque(y), retblock)
|
|
}
|
|
|
|
retblock = {
|
|
Return()
|
|
}
|
|
)
|
|
}
|
|
|
|
#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
|
|
fn dominate_storage() {
|
|
use std::intrinsics::mir::*;
|
|
|
|
mir!(
|
|
let x: i32;
|
|
let r: &i32;
|
|
let c: i32;
|
|
let d: bool;
|
|
{ Goto(bb0) }
|
|
bb0 = {
|
|
x = 5;
|
|
r = &x;
|
|
Goto(bb1)
|
|
}
|
|
bb1 = {
|
|
let c = *r;
|
|
Call(RET = opaque(c), bb2)
|
|
}
|
|
bb2 = {
|
|
StorageDead(x);
|
|
StorageLive(x);
|
|
let d = true;
|
|
match d { false => bb2, _ => bb0 }
|
|
}
|
|
)
|
|
}
|
|
|
|
#[custom_mir(dialect = "runtime", phase = "post-cleanup")]
|
|
fn maybe_dead(m: bool) {
|
|
use std::intrinsics::mir::*;
|
|
|
|
mir!(
|
|
let x: i32;
|
|
let y: i32;
|
|
{
|
|
StorageLive(x);
|
|
StorageLive(y);
|
|
x = 5;
|
|
y = 5;
|
|
let a = &x;
|
|
let b = &mut y;
|
|
// As we don't replace `b` in `bb2`, we cannot replace it here either.
|
|
*b = 7;
|
|
// But this can still be replaced.
|
|
let u = *a;
|
|
match m { true => bb1, _ => bb2 }
|
|
}
|
|
bb1 = {
|
|
StorageDead(x);
|
|
StorageDead(y);
|
|
Call(RET = opaque(u), bb2)
|
|
}
|
|
bb2 = {
|
|
// As `x` may be `StorageDead`, `a` may be dangling, so we do nothing.
|
|
let z = *a;
|
|
Call(RET = opaque(z), bb3)
|
|
}
|
|
bb3 = {
|
|
// As `y` may be `StorageDead`, `b` may be dangling, so we do nothing.
|
|
// This implies that we also do not substitute `b` in `bb0`.
|
|
let t = *b;
|
|
Call(RET = opaque(t), retblock)
|
|
}
|
|
retblock = {
|
|
Return()
|
|
}
|
|
)
|
|
}
|
|
|
|
fn mut_raw_then_mut_shr() -> (i32, i32) {
|
|
let mut x = 2;
|
|
let xref = &mut x;
|
|
let xraw = &mut *xref as *mut _;
|
|
let xshr = &*xref;
|
|
// Verify that we completely replace with `x` in both cases.
|
|
let a = *xshr;
|
|
unsafe { *xraw = 4; }
|
|
(a, x)
|
|
}
|
|
|
|
fn unique_with_copies() {
|
|
let y = {
|
|
let mut a = 0;
|
|
let x = &raw mut a;
|
|
// `*y` is not replacable below, so we must not replace `*x`.
|
|
unsafe { opaque(*x) };
|
|
x
|
|
};
|
|
// But rewriting as `*x` is ok.
|
|
unsafe { opaque(*y) };
|
|
}
|
|
|
|
fn debuginfo() {
|
|
struct T(u8);
|
|
|
|
let ref_mut_u8 = &mut 5_u8;
|
|
let field = &T(0).0;
|
|
|
|
// Verify that we don't emit `&*` in debuginfo.
|
|
let reborrow = &*ref_mut_u8;
|
|
|
|
match Some(0) {
|
|
None => {}
|
|
Some(ref variant_field) => {}
|
|
}
|
|
|
|
// `constant_index_from_end` and `subslice` should not be promoted, as their value depends
|
|
// on the slice length.
|
|
if let [_, ref constant_index, subslice @ .., ref constant_index_from_end] = &[6; 10][..] {
|
|
}
|
|
|
|
let multiple_borrow = &&&mut T(6).0;
|
|
}
|
|
|
|
fn many_debuginfo() {
|
|
let a = 0;
|
|
|
|
// Verify that we do not ICE on deeply nested borrows.
|
|
let many_borrow =
|
|
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
|
|
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
|
|
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
|
|
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
|
|
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&a;
|
|
}
|
|
|
|
fn main() {
|
|
let mut x = 5_usize;
|
|
let mut y = 7_usize;
|
|
reference_propagation(&x, &y);
|
|
reference_propagation_mut(&mut x, &mut y);
|
|
reference_propagation_const_ptr(&raw const x, &raw const y);
|
|
reference_propagation_mut_ptr(&raw mut x, &raw mut y);
|
|
read_through_raw(&mut x);
|
|
multiple_storage();
|
|
dominate_storage();
|
|
maybe_dead(true);
|
|
mut_raw_then_mut_shr();
|
|
unique_with_copies();
|
|
debuginfo();
|
|
many_debuginfo();
|
|
}
|
|
|
|
// EMIT_MIR reference_prop.reference_propagation.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.reference_propagation_mut.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.reference_propagation_const_ptr.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.reference_propagation_mut_ptr.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.read_through_raw.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.multiple_storage.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.dominate_storage.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.maybe_dead.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.mut_raw_then_mut_shr.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.unique_with_copies.ReferencePropagation.diff
|
|
// EMIT_MIR reference_prop.debuginfo.ReferencePropagation.diff
|