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Heap2Local: Fix signed struct/array reads #6484

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Merged
kripken merged 1 commit into from
Apr 10, 2024
Merged

Heap2Local: Fix signed struct/array reads #6484

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15 changes: 10 additions & 5 deletions src/passes/Heap2Local.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -652,7 +652,7 @@ struct Struct2Local : PostWalker<Struct2Local> {
// Add a mask for packed fields. We add masks on sets rather than on gets
// because gets tend to be more numerous both in code appearances and in
// runtime execution. As a result of masking on sets, the value in the local
// is always the masked value (which is also nice for debugging,
// is always the masked unsigned value (which is also nice for debugging,
// incidentally).
Expression* addMask(Expression* value, const Field& field) {
if (!field.isPacked()) {
Expand Down Expand Up @@ -795,7 +795,8 @@ struct Struct2Local : PostWalker<Struct2Local> {
return;
}

auto type = fields[curr->index].type;
auto& field = fields[curr->index];
auto type = field.type;
if (type != curr->type) {
// Normally we are just replacing a struct.get with a local.get of a
// local that was created to have the same type as the struct's field,
Expand All @@ -811,9 +812,13 @@ struct Struct2Local : PostWalker<Struct2Local> {
// which may be more refined.
refinalize = true;
}
replaceCurrent(builder.makeSequence(
builder.makeDrop(curr->ref),
builder.makeLocalGet(localIndexes[curr->index], type)));
Expression* value = builder.makeLocalGet(localIndexes[curr->index], type);
if (field.isPacked() && curr->signed_) {
// The value in the local is the masked unsigned value, which we must
// sign-extend.
value = Bits::makeSignExt(value, field.getByteSize(), wasm);
}
replaceCurrent(builder.makeSequence(builder.makeDrop(curr->ref), value));
}
};

Expand Down
69 changes: 58 additions & 11 deletions test/lit/passes/heap2local.wast
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Original file line number Diff line number Diff line change
Expand Up @@ -221,6 +221,20 @@
;; CHECK-NEXT: (local.get $1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (ref.null none)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.shr_s
;; CHECK-NEXT: (i32.shl
;; CHECK-NEXT: (local.get $1)
;; CHECK-NEXT: (i32.const 24)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 24)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (block
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (ref.null none)
Expand Down Expand Up @@ -268,6 +282,12 @@
(local.get $temp)
)
)
;; Signed gets require us to sign-extend them.
(drop
(struct.get_s $struct.packed 0
(local.get $temp)
)
)
;; Unpacked fields in the same struct do not need anything.
(struct.set $struct.packed 1
(local.get $temp)
Expand Down Expand Up @@ -3409,15 +3429,17 @@

;; Packed arrays.
(module
;; CHECK: (type $0 (func (result i32)))
;; CHECK: (type $0 (func))

;; CHECK: (type $array8 (array (mut i8)))
(type $array8 (array (mut i8)))

;; CHECK: (type $2 (func (result i32)))

;; CHECK: (type $array16 (array (mut i16)))
(type $array16 (array (mut i16)))

;; CHECK: (func $array8 (type $0) (result i32)
;; CHECK: (func $array8 (type $0)
;; CHECK-NEXT: (local $temp (ref $array8))
;; CHECK-NEXT: (local $1 i32)
;; CHECK-NEXT: (local $2 i32)
Expand Down Expand Up @@ -3447,14 +3469,30 @@
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (ref.null none)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (ref.null none)
;; CHECK-NEXT: )
;; CHECK-NEXT: (local.get $2)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (ref.null none)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.shr_s
;; CHECK-NEXT: (i32.shl
;; CHECK-NEXT: (local.get $2)
;; CHECK-NEXT: (i32.const 24)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 24)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (local.get $2)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $array8 (result i32)
(func $array8
(local $temp (ref $array8))
(local.set $temp
(array.new_default $array8
Expand All @@ -3466,13 +3504,22 @@
(i32.const 1)
(i32.const 1337)
)
(array.get $array8
(local.get $temp)
(i32.const 1)
(drop
(array.get $array8
(local.get $temp)
(i32.const 1)
)
)
;; As with structs, a signed get causes us to emit a sign extend.
(drop
(array.get_s $array8
(local.get $temp)
(i32.const 1)
)
)
)

;; CHECK: (func $array16 (type $0) (result i32)
;; CHECK: (func $array16 (type $2) (result i32)
;; CHECK-NEXT: (local $temp (ref $array16))
;; CHECK-NEXT: (local $1 i32)
;; CHECK-NEXT: (local $2 i32)
Expand Down