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Rollup merge of #71590 - RalfJung:mir-dump-pointers, r=oli-obk
MIR dump: print pointers consistently with Miri output This makes MIR allocation dump pointer printing consistent with Miri output: both use hexadecimal offsets with a `0x` prefix. To save some space, MIR dump replaces the `alloc` prefix by `a` when necessary. I also made AllocId/Pointer printing more consistent in their Debug/Display handling, and adjusted Display printing for Scalar a bit to avoid using decimal printing when we do not know the sign with which to interpret the value (IMO using decimal then is misleading).
2 parents 01fffff + b12faeb commit 3c75f70

22 files changed

+131
-97
lines changed

‎src/librustc_middle/mir/interpret/mod.rs

Lines changed: 5 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -168,15 +168,17 @@ pub enum LitToConstError {
168168
#[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]
169169
pub struct AllocId(pub u64);
170170

171+
// We want the `Debug` output to be readable as it is used by `derive(Debug)` for
172+
// all the Miri types.
171173
impl fmt::Debug for AllocId {
172-
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
173-
fmt::Display::fmt(self, fmt)
174+
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
175+
if f.alternate() { write!(f, "a{}", self.0) } else { write!(f, "alloc{}", self.0) }
174176
}
175177
}
176178

177179
impl fmt::Display for AllocId {
178180
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
179-
write!(f, "alloc{}", self.0)
181+
fmt::Debug::fmt(self, f)
180182
}
181183
}
182184

‎src/librustc_middle/mir/interpret/pointer.rs

Lines changed: 20 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -119,15 +119,33 @@ pub struct Pointer<Tag = (), Id = AllocId> {
119119

120120
static_assert_size!(Pointer, 16);
121121

122+
// We want the `Debug` output to be readable as it is used by `derive(Debug)` for
123+
// all the Miri types.
124+
// We have to use `Debug` output for the tag, because `()` does not implement
125+
// `Display` so we cannot specialize that.
122126
impl<Tag: fmt::Debug, Id: fmt::Debug> fmt::Debug for Pointer<Tag, Id> {
123127
default fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
124-
write!(f, "{:?}+0x{:x}[{:?}]", self.alloc_id, self.offset.bytes(), self.tag)
128+
if f.alternate() {
129+
write!(f, "{:#?}+0x{:x}[{:?}]", self.alloc_id, self.offset.bytes(), self.tag)
130+
} else {
131+
write!(f, "{:?}+0x{:x}[{:?}]", self.alloc_id, self.offset.bytes(), self.tag)
132+
}
125133
}
126134
}
127135
// Specialization for no tag
128136
impl<Id: fmt::Debug> fmt::Debug for Pointer<(), Id> {
129137
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
130-
write!(f, "{:?}+0x{:x}", self.alloc_id, self.offset.bytes())
138+
if f.alternate() {
139+
write!(f, "{:#?}+0x{:x}", self.alloc_id, self.offset.bytes())
140+
} else {
141+
write!(f, "{:?}+0x{:x}", self.alloc_id, self.offset.bytes())
142+
}
143+
}
144+
}
145+
146+
impl<Tag: fmt::Debug> fmt::Display for Pointer<Tag> {
147+
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
148+
fmt::Debug::fmt(self, f)
131149
}
132150
}
133151

‎src/librustc_middle/mir/interpret/value.rs

Lines changed: 9 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -107,6 +107,8 @@ pub enum Scalar<Tag = (), Id = AllocId> {
107107
#[cfg(target_arch = "x86_64")]
108108
static_assert_size!(Scalar, 24);
109109

110+
// We want the `Debug` output to be readable as it is used by `derive(Debug)` for
111+
// all the Miri types.
110112
impl<Tag: fmt::Debug, Id: fmt::Debug> fmt::Debug for Scalar<Tag, Id> {
111113
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
112114
match self {
@@ -125,11 +127,11 @@ impl<Tag: fmt::Debug, Id: fmt::Debug> fmt::Debug for Scalar<Tag, Id> {
125127
}
126128
}
127129

128-
impl<Tag> fmt::Display for Scalar<Tag> {
130+
impl<Tag: fmt::Debug> fmt::Display for Scalar<Tag> {
129131
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
130132
match self {
131-
Scalar::Ptr(_) => write!(f, "a pointer"),
132-
Scalar::Raw { data, .. } => write!(f, "{}", data),
133+
Scalar::Ptr(ptr) => write!(f, "pointer to {}", ptr),
134+
Scalar::Raw { .. } => fmt::Debug::fmt(self, f),
133135
}
134136
}
135137
}
@@ -559,16 +561,18 @@ impl<Tag> From<Pointer<Tag>> for ScalarMaybeUndef<Tag> {
559561
}
560562
}
561563

564+
// We want the `Debug` output to be readable as it is used by `derive(Debug)` for
565+
// all the Miri types.
562566
impl<Tag: fmt::Debug, Id: fmt::Debug> fmt::Debug for ScalarMaybeUndef<Tag, Id> {
563567
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
564568
match self {
565-
ScalarMaybeUndef::Undef => write!(f, "Undef"),
569+
ScalarMaybeUndef::Undef => write!(f, "<uninitialized>"),
566570
ScalarMaybeUndef::Scalar(s) => write!(f, "{:?}", s),
567571
}
568572
}
569573
}
570574

571-
impl<Tag> fmt::Display for ScalarMaybeUndef<Tag> {
575+
impl<Tag: fmt::Debug> fmt::Display for ScalarMaybeUndef<Tag> {
572576
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
573577
match self {
574578
ScalarMaybeUndef::Undef => write!(f, "uninitialized bytes"),

‎src/librustc_mir/interpret/machine.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -84,6 +84,8 @@ pub trait Machine<'mir, 'tcx>: Sized {
8484
/// Tag tracked alongside every pointer. This is used to implement "Stacked Borrows"
8585
/// <https://www.ralfj.de/blog/2018/08/07/stacked-borrows.html>.
8686
/// The `default()` is used for pointers to consts, statics, vtables and functions.
87+
/// The `Debug` formatting is used for displaying pointers; we cannot use `Display`
88+
/// as `()` does not implement that, but it should be "nice" output.
8789
type PointerTag: ::std::fmt::Debug + Copy + Eq + Hash + 'static;
8890

8991
/// Machines can define extra (non-instance) things that represent values of function pointers.

‎src/librustc_mir/interpret/memory.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -674,7 +674,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
674674
/// control for this.
675675
pub fn dump_allocs(&self, mut allocs: Vec<AllocId>) {
676676
// Cannot be a closure because it is generic in `Tag`, `Extra`.
677-
fn write_allocation_track_relocs<'tcx, Tag, Extra>(
677+
fn write_allocation_track_relocs<'tcx, Tag: Copy + fmt::Debug, Extra>(
678678
tcx: TyCtxtAt<'tcx>,
679679
allocs_to_print: &mut VecDeque<AllocId>,
680680
alloc: &Allocation<Tag, Extra>,

‎src/librustc_mir/interpret/operand.rs

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -122,11 +122,11 @@ impl<Tag: Copy> std::fmt::Display for ImmTy<'tcx, Tag> {
122122
p(cx, s, ty)?;
123123
return Ok(());
124124
}
125-
write!(f, "{:?}: {}", s.erase_tag(), self.layout.ty)
125+
write!(f, "{}: {}", s.erase_tag(), self.layout.ty)
126126
}
127127
Immediate::ScalarPair(a, b) => {
128128
// FIXME(oli-obk): at least print tuples and slices nicely
129-
write!(f, "({:?}, {:?}): {}", a.erase_tag(), b.erase_tag(), self.layout.ty,)
129+
write!(f, "({}, {}): {}", a.erase_tag(), b.erase_tag(), self.layout.ty,)
130130
}
131131
}
132132
})

‎src/librustc_mir/util/pretty.rs

Lines changed: 18 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -1,22 +1,23 @@
1+
use std::collections::BTreeSet;
2+
use std::fmt::Write as _;
3+
use std::fmt::{Debug, Display};
4+
use std::fs;
5+
use std::io::{self, Write};
6+
use std::path::{Path, PathBuf};
7+
18
use super::graphviz::write_mir_fn_graphviz;
29
use crate::transform::MirSource;
310
use either::Either;
411
use rustc_data_structures::fx::FxHashMap;
512
use rustc_hir::def_id::{DefId, LOCAL_CRATE};
613
use rustc_index::vec::Idx;
714
use rustc_middle::mir::interpret::{
8-
read_target_uint, AllocId, Allocation, ConstValue, GlobalAlloc,
15+
read_target_uint, AllocId, Allocation, ConstValue, GlobalAlloc, Pointer,
916
};
1017
use rustc_middle::mir::visit::Visitor;
1118
use rustc_middle::mir::*;
1219
use rustc_middle::ty::{self, TyCtxt, TypeFoldable, TypeVisitor};
1320
use rustc_target::abi::Size;
14-
use std::collections::BTreeSet;
15-
use std::fmt::Display;
16-
use std::fmt::Write as _;
17-
use std::fs;
18-
use std::io::{self, Write};
19-
use std::path::{Path, PathBuf};
2021

2122
const INDENT: &str = " ";
2223
/// Alignment for lining up comments following MIR statements
@@ -635,7 +636,7 @@ pub fn write_allocations<'tcx>(
635636
/// After the hex dump, an ascii dump follows, replacing all unprintable characters (control
636637
/// characters or characters whose value is larger than 127) with a `.`
637638
/// This also prints relocations adequately.
638-
pub fn write_allocation<Tag, Extra>(
639+
pub fn write_allocation<Tag: Copy + Debug, Extra>(
639640
tcx: TyCtxt<'tcx>,
640641
alloc: &Allocation<Tag, Extra>,
641642
w: &mut dyn Write,
@@ -679,7 +680,7 @@ fn write_allocation_newline(
679680
/// The `prefix` argument allows callers to add an arbitrary prefix before each line (even if there
680681
/// is only one line). Note that your prefix should contain a trailing space as the lines are
681682
/// printed directly after it.
682-
fn write_allocation_bytes<Tag, Extra>(
683+
fn write_allocation_bytes<Tag: Copy + Debug, Extra>(
683684
tcx: TyCtxt<'tcx>,
684685
alloc: &Allocation<Tag, Extra>,
685686
w: &mut dyn Write,
@@ -715,14 +716,20 @@ fn write_allocation_bytes<Tag, Extra>(
715716
if i != line_start {
716717
write!(w, " ")?;
717718
}
718-
if let Some(&(_, target_id)) = alloc.relocations().get(&i) {
719+
if let Some(&(tag, target_id)) = alloc.relocations().get(&i) {
719720
// Memory with a relocation must be defined
720721
let j = i.bytes_usize();
721722
let offset =
722723
alloc.inspect_with_undef_and_ptr_outside_interpreter(j..j + ptr_size.bytes_usize());
723724
let offset = read_target_uint(tcx.data_layout.endian, offset).unwrap();
725+
let offset = Size::from_bytes(offset);
724726
let relocation_width = |bytes| bytes * 3;
725-
let mut target = format!("{}+{}", target_id, offset);
727+
let ptr = Pointer::new_with_tag(target_id, offset, tag);
728+
let mut target = format!("{:?}", ptr);
729+
if target.len() > relocation_width(ptr_size.bytes_usize() - 1) {
730+
// This is too long, try to save some space.
731+
target = format!("{:#?}", ptr);
732+
}
726733
if ((i - line_start) + ptr_size).bytes_usize() > BYTES_PER_LINE {
727734
// This branch handles the situation where a relocation starts in the current line
728735
// but ends in the next one.

‎src/test/mir-opt/const_allocation/32bit/rustc.main.ConstProp.after.mir

Lines changed: 7 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -30,19 +30,19 @@ fn main() -> () {
3030
}
3131

3232
alloc0 (static: FOO, size: 8, align: 4) {
33-
╾alloc17+0╼ 03 00 00 00 │ ╾──╼....
33+
╾─a17+0x0─╼ 03 00 00 00 │ ╾──╼....
3434
}
3535

3636
alloc17 (size: 48, align: 4) {
37-
0x00 │ 00 00 00 00 __ __ __ __ ╾alloc4+0─╼ 00 00 00 00 │ ....░░░░╾──╼....
38-
0x10 │ 00 00 00 00 __ __ __ __ ╾alloc8+0─╼ 02 00 00 00 │ ....░░░░╾──╼....
39-
0x20 │ 01 00 00 00 2a 00 00 00 ╾alloc13+0╼ 03 00 00 00 │ ....*...╾──╼....
37+
0x00 │ 00 00 00 00 __ __ __ __ ╾─a4+0x0──╼ 00 00 00 00 │ ....░░░░╾──╼....
38+
0x10 │ 00 00 00 00 __ __ __ __ ╾─a8+0x0──╼ 02 00 00 00 │ ....░░░░╾──╼....
39+
0x20 │ 01 00 00 00 2a 00 00 00 ╾─a13+0x0─╼ 03 00 00 00 │ ....*...╾──╼....
4040
}
4141

4242
alloc4 (size: 0, align: 4) {}
4343

4444
alloc8 (size: 16, align: 4) {
45-
╾alloc7+0─╼ 03 00 00 00 ╾alloc9+0─╼ 03 00 00 00 │ ╾──╼....╾──╼....
45+
╾─a7+0x0──╼ 03 00 00 00 ╾─a9+0x0──╼ 03 00 00 00 │ ╾──╼....╾──╼....
4646
}
4747

4848
alloc7 (size: 3, align: 1) {
@@ -54,8 +54,8 @@ alloc9 (size: 3, align: 1) {
5454
}
5555

5656
alloc13 (size: 24, align: 4) {
57-
0x00 │ ╾alloc12+0╼ 03 00 00 00 ╾alloc14+0╼ 03 00 00 00 │ ╾──╼....╾──╼....
58-
0x10 │ ╾alloc15+0╼ 04 00 00 00 │ ╾──╼....
57+
0x00 │ ╾─a12+0x0─╼ 03 00 00 00 ╾─a14+0x0─╼ 03 00 00 00 │ ╾──╼....╾──╼....
58+
0x10 │ ╾─a15+0x0─╼ 04 00 00 00 │ ╾──╼....
5959
}
6060

6161
alloc12 (size: 3, align: 1) {

‎src/test/mir-opt/const_allocation/64bit/rustc.main.ConstProp.after.mir

Lines changed: 9 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -30,22 +30,22 @@ fn main() -> () {
3030
}
3131

3232
alloc0 (static: FOO, size: 16, align: 8) {
33-
╾──────alloc17+0──────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
33+
╾─────alloc17+0x0─────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
3434
}
3535

3636
alloc17 (size: 72, align: 8) {
37-
0x00 │ 00 00 00 00 __ __ __ __ ╾──────alloc4+0───────╼ │ ....░░░░╾──────╼
37+
0x00 │ 00 00 00 00 __ __ __ __ ╾─────alloc4+0x0──────╼ │ ....░░░░╾──────╼
3838
0x10 │ 00 00 00 00 00 00 00 00 00 00 00 00 __ __ __ __ │ ............░░░░
39-
0x20 │ ╾──────alloc8+0───────╼ 02 00 00 00 00 00 00 00 │ ╾──────╼........
40-
0x30 │ 01 00 00 00 2a 00 00 00 ╾──────alloc13+0──────╼ │ ....*...╾──────╼
39+
0x20 │ ╾─────alloc8+0x0──────╼ 02 00 00 00 00 00 00 00 │ ╾──────╼........
40+
0x30 │ 01 00 00 00 2a 00 00 00 ╾─────alloc13+0x0─────╼ │ ....*...╾──────╼
4141
0x40 │ 03 00 00 00 00 00 00 00 │ ........
4242
}
4343

4444
alloc4 (size: 0, align: 8) {}
4545

4646
alloc8 (size: 32, align: 8) {
47-
0x00 │ ╾──────alloc7+0───────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
48-
0x10 │ ╾──────alloc9+0───────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
47+
0x00 │ ╾─────alloc7+0x0──────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
48+
0x10 │ ╾─────alloc9+0x0──────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
4949
}
5050

5151
alloc7 (size: 3, align: 1) {
@@ -57,9 +57,9 @@ alloc9 (size: 3, align: 1) {
5757
}
5858

5959
alloc13 (size: 48, align: 8) {
60-
0x00 │ ╾──────alloc12+0──────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
61-
0x10 │ ╾──────alloc14+0──────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
62-
0x20 │ ╾──────alloc15+0──────╼ 04 00 00 00 00 00 00 00 │ ╾──────╼........
60+
0x00 │ ╾─────alloc12+0x0─────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
61+
0x10 │ ╾─────alloc14+0x0─────╼ 03 00 00 00 00 00 00 00 │ ╾──────╼........
62+
0x20 │ ╾─────alloc15+0x0─────╼ 04 00 00 00 00 00 00 00 │ ╾──────╼........
6363
}
6464

6565
alloc12 (size: 3, align: 1) {

‎src/test/mir-opt/const_allocation2/32bit/rustc.main.ConstProp.after.mir

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -30,19 +30,19 @@ fn main() -> () {
3030
}
3131

3232
alloc0 (static: FOO, size: 8, align: 4) {
33-
╾alloc21+0╼ 03 00 00 00 │ ╾──╼....
33+
╾─a21+0x0─╼ 03 00 00 00 │ ╾──╼....
3434
}
3535

3636
alloc21 (size: 48, align: 4) {
37-
0x00 │ 00 00 00 00 __ __ __ __ ╾alloc4+0─╼ 00 00 00 00 │ ....░░░░╾──╼....
38-
0x10 │ 00 00 00 00 __ __ __ __ ╾alloc9+0─╼ 02 00 00 00 │ ....░░░░╾──╼....
39-
0x20 │ 01 00 00 00 2a 00 00 00 ╾alloc19+0╼ 03 00 00 00 │ ....*...╾──╼....
37+
0x00 │ 00 00 00 00 __ __ __ __ ╾─a4+0x0──╼ 00 00 00 00 │ ....░░░░╾──╼....
38+
0x10 │ 00 00 00 00 __ __ __ __ ╾─a9+0x0──╼ 02 00 00 00 │ ....░░░░╾──╼....
39+
0x20 │ 01 00 00 00 2a 00 00 00 ╾─a19+0x0─╼ 03 00 00 00 │ ....*...╾──╼....
4040
}
4141

4242
alloc4 (size: 0, align: 4) {}
4343

4444
alloc9 (size: 8, align: 4) {
45-
╾alloc7+0─╼ ╾alloc8+0─╼ │ ╾──╼╾──╼
45+
╾─a7+0x0──╼ ╾─a8+0x0──╼ │ ╾──╼╾──╼
4646
}
4747

4848
alloc7 (size: 1, align: 1) {
@@ -54,7 +54,7 @@ alloc8 (size: 1, align: 1) {
5454
}
5555

5656
alloc19 (size: 12, align: 4) {
57-
╾alloc15+3╼ ╾alloc16+0╼ ╾alloc18+2╼ │ ╾──╼╾──╼╾──╼
57+
╾─a15+0x3─╼ ╾─a16+0x0─╼ ╾─a18+0x2─╼ │ ╾──╼╾──╼╾──╼
5858
}
5959

6060
alloc15 (size: 4, align: 1) {

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