Skip to content

Fix Precompute visitArrayGet missing memory ordering check #8327

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
sumleo wants to merge 1 commit into
base: main
Choose a base branch
from
+122 −6
Open

Fix Precompute visitArrayGet missing memory ordering check #8327

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
29 changes: 23 additions & 6 deletions src/passes/Precompute.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -185,12 +185,29 @@ class PrecomputingExpressionRunner
}
Flow visitArraySet(ArraySet* curr) { return Flow(NONCONSTANT_FLOW); }
Flow visitArrayGet(ArrayGet* curr) {
if (curr->ref->type != Type::unreachable && !curr->ref->type.isNull()) {
// See above with struct.get
auto element = curr->ref->type.getHeapType().getArray().element;
if (element.mutable_ == Immutable) {
return Super::visitArrayGet(curr);
}
if (curr->ref->type == Type::unreachable || curr->ref->type.isNull()) {
return Flow(NONCONSTANT_FLOW);
}
switch (curr->order) {
case MemoryOrder::Unordered:
// This can always be precomputed.
break;
case MemoryOrder::SeqCst:
// This can never be precomputed away because it synchronizes with other
// threads.
return Flow(NONCONSTANT_FLOW);
case MemoryOrder::AcqRel:
// This synchronizes only with writes to the same data, so it can still
// be precomputed if the data is not shared with other threads.
if (curr->ref->type.getHeapType().isShared()) {
return Flow(NONCONSTANT_FLOW);
}
break;
}
// See above with struct.get
auto element = curr->ref->type.getHeapType().getArray().element;
if (element.mutable_ == Immutable) {
return Super::visitArrayGet(curr);
}

// Otherwise, we've failed to precompute.
Expand Down
99 changes: 99 additions & 0 deletions test/lit/passes/precompute-gc-atomics.wast
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,9 +5,13 @@
(module
;; CHECK: (type $shared (shared (struct (field i32))))
(type $shared (shared (struct (field i32))))
;; CHECK: (type $shared-array (shared (array i32)))

;; CHECK: (type $unshared (struct (field i32)))
(type $unshared (struct (field i32)))

;; CHECK: (type $unshared-array (array i32))

;; CHECK: (func $get-unordered-unshared (type $0) (result i32)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
Expand Down Expand Up @@ -69,4 +73,99 @@
(struct.new_default $shared)
)
)

;; Array versions of the same tests. These should behave the same as the
;; struct versions above.

(type $shared-array (shared (array i32)))
(type $unshared-array (array i32))

;; CHECK: (func $array-get-unordered-unshared (type $0) (result i32)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
(func $array-get-unordered-unshared (result i32)
(array.get $unshared-array
(array.new_default $unshared-array
(i32.const 1)
)
(i32.const 0)
)
)

;; CHECK: (func $array-get-unordered-shared (type $0) (result i32)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
(func $array-get-unordered-shared (result i32)
(array.get $shared-array
(array.new_default $shared-array
(i32.const 1)
)
(i32.const 0)
)
)

;; CHECK: (func $array-get-seqcst-unshared (type $0) (result i32)
;; CHECK-NEXT: (array.atomic.get $unshared-array
;; CHECK-NEXT: (array.new_default $unshared-array
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $array-get-seqcst-unshared (result i32)
(array.atomic.get seqcst $unshared-array
(array.new_default $unshared-array
(i32.const 1)
)
(i32.const 0)
)
)

;; CHECK: (func $array-get-seqcst-shared (type $0) (result i32)
;; CHECK-NEXT: (array.atomic.get $shared-array
;; CHECK-NEXT: (array.new_default $shared-array
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $array-get-seqcst-shared (result i32)
(array.atomic.get seqcst $shared-array
(array.new_default $shared-array
(i32.const 1)
)
(i32.const 0)
)
)

;; CHECK: (func $array-get-acqrel-unshared (type $0) (result i32)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
(func $array-get-acqrel-unshared (result i32)
;; We can optimize this because acquire-release on unshared data does not
;; synchronize with anything.
(array.atomic.get acqrel $unshared-array
(array.new_default $unshared-array
(i32.const 1)
)
(i32.const 0)
)
)

;; CHECK: (func $array-get-acqrel-shared (type $0) (result i32)
;; CHECK-NEXT: (array.atomic.get acqrel $shared-array
;; CHECK-NEXT: (array.new_default $shared-array
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $array-get-acqrel-shared (result i32)
(array.atomic.get acqrel $shared-array
(array.new_default $shared-array
(i32.const 1)
)
(i32.const 0)
)
)
)
Loading