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Smaller epsilon towards determinism #125

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c12fd46
Sort output vectors by content-derived keys for deterministic JSON ou…
cds-amal Feb 22, 2026
6f68636
Make style-check match CI by adding -Dwarnings to clippy
cds-amal Feb 23, 2026
1d282d5
Fix clippy unnecessary_sort_by lint in alloc sorting
cds-amal Feb 23, 2026
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2 changes: 1 addition & 1 deletion Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,7 @@ format:
bash -O globstar -c 'nixfmt **/*.nix'

style-check: format
cargo clippy
cargo clippy -- -Dwarnings

.PHONY: remake-ui-tests test-ui

Expand Down
39 changes: 33 additions & 6 deletions src/printer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1137,6 +1137,10 @@ pub enum TypeMetadata {
PrimitiveType(RigidTy),
EnumType {
name: String,
// adt_def serializes as a non-deterministic interned index (DefId), but
// downstream consumers need it to cross-reference AggregateKind::Adt in
// MIR bodies with the type metadata here. We can't stabilize it without
// also controlling AggregateKind serialization (which comes from stable_mir).
adt_def: AdtDef,
discriminants: Vec<u128>,
fields: Vec<Vec<stable_mir::ty::Ty>>,
Expand Down Expand Up @@ -1372,6 +1376,15 @@ impl AllocInfo {
}
}

fn alloc_sort_key(info: &AllocInfo) -> String {
match info.global_alloc() {
GlobalAlloc::Memory(alloc) => format!("0_Memory_{:020}", alloc.bytes.len()),
GlobalAlloc::Static(def) => format!("1_Static_{}", def.name()),
GlobalAlloc::VTable(ty, _) => format!("2_VTable_{}", ty),
GlobalAlloc::Function(inst) => format!("3_Function_{}", inst.name()),
}
}

// Serialization Entrypoint
// ========================

Expand Down Expand Up @@ -1435,19 +1448,33 @@ pub fn collect_smir(tcx: TyCtxt<'_>) -> SmirJson {

let mut spans = span_map.into_iter().collect::<Vec<_>>();

// sort output vectors to stabilise output (a bit)
allocs.sort_by(|a, b| a.alloc_id.to_index().cmp(&b.alloc_id.to_index()));
functions.sort_by(|a, b| a.0 .0.to_index().cmp(&b.0 .0.to_index()));
// sort output vectors by content-derived keys for deterministic output.
// Ty's Display impl (ty_pretty) should be injective for monomorphized types,
// but we use the interned index as a tiebreaker just in case two distinct
// types produce the same display string.
allocs.sort_by_key(alloc_sort_key);
functions.sort_by(|a, b| {
format!("{}", a.0 .0)
.cmp(&format!("{}", b.0 .0))
.then_with(|| a.0 .0.to_index().cmp(&b.0 .0.to_index()))
});
items.sort();
types.sort_by(|a, b| a.0.to_index().cmp(&b.0.to_index()));
spans.sort();
types.sort_by(|a, b| {
format!("{}", a.0)
.cmp(&format!("{}", b.0))
.then_with(|| a.0.to_index().cmp(&b.0.to_index()))
});
spans.sort_by(|a, b| a.1.cmp(&b.1));

let mut uneval_consts: Vec<_> = unevaluated_consts.into_iter().collect();
uneval_consts.sort_by(|a, b| a.1.cmp(&b.1));

SmirJson {
name: local_crate.name,
crate_id,
allocs,
functions,
uneval_consts: unevaluated_consts.into_iter().collect(),
uneval_consts,
items,
types,
spans,
Expand Down
104 changes: 52 additions & 52 deletions tests/integration/programs/assert_eq.smir.json.expected
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Original file line number Diff line number Diff line change
Expand Up @@ -4760,34 +4760,6 @@
}
}
],
[
{
"TupleType": {
"layout": {
"abi": {
"Aggregate": {
"sized": true
}
},
"abi_align": 1,
"fields": {
"Arbitrary": {
"offsets": []
}
},
"size": {
"num_bits": 0
},
"variants": {
"Single": {
"index": 0
}
}
},
"types": "elided"
}
}
],
[
{
"TupleType": {
Expand All @@ -4797,48 +4769,70 @@
{
"Initialized": {
"valid_range": {
"end": 4294967295,
"start": 0
"end": 18446744073709551615,
"start": 1
},
"value": {
"Int": {
"length": "I32",
"signed": true
}
"Pointer": 0
}
}
},
{
"Initialized": {
"valid_range": {
"end": 1,
"start": 0
"end": 18446744073709551615,
"start": 1
},
"value": {
"Int": {
"length": "I8",
"signed": false
}
"Pointer": 0
}
}
}
]
},
"abi_align": 4,
"abi_align": 8,
"fields": {
"Arbitrary": {
"offsets": [
{
"num_bits": 0
},
{
"num_bits": 32
"num_bits": 64
}
]
}
},
"size": {
"num_bits": 64
"num_bits": 128
},
"variants": {
"Single": {
"index": 0
}
}
},
"types": "elided"
}
}
],
[
{
"TupleType": {
"layout": {
"abi": {
"Aggregate": {
"sized": true
}
},
"abi_align": 1,
"fields": {
"Arbitrary": {
"offsets": []
}
},
"size": {
"num_bits": 0
},
"variants": {
"Single": {
Expand All @@ -4859,42 +4853,48 @@
{
"Initialized": {
"valid_range": {
"end": 18446744073709551615,
"start": 1
"end": 4294967295,
"start": 0
},
"value": {
"Pointer": 0
"Int": {
"length": "I32",
"signed": true
}
}
}
},
{
"Initialized": {
"valid_range": {
"end": 18446744073709551615,
"start": 1
"end": 1,
"start": 0
},
"value": {
"Pointer": 0
"Int": {
"length": "I8",
"signed": false
}
}
}
}
]
},
"abi_align": 8,
"abi_align": 4,
"fields": {
"Arbitrary": {
"offsets": [
{
"num_bits": 0
},
{
"num_bits": 64
"num_bits": 32
}
]
}
},
"size": {
"num_bits": 128
"num_bits": 64
},
"variants": {
"Single": {
Expand Down
12 changes: 6 additions & 6 deletions tests/integration/programs/closure-args.smir.json.expected
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Original file line number Diff line number Diff line change
Expand Up @@ -2131,13 +2131,13 @@
{
"Initialized": {
"valid_range": {
"end": 4294967295,
"end": 1,
"start": 0
},
"value": {
"Int": {
"length": "I32",
"signed": true
"length": "I8",
"signed": false
}
}
}
Expand Down Expand Up @@ -2193,13 +2193,13 @@
{
"Initialized": {
"valid_range": {
"end": 1,
"end": 4294967295,
"start": 0
},
"value": {
"Int": {
"length": "I8",
"signed": false
"length": "I32",
"signed": true
}
}
}
Expand Down
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