Skip to content

[CtorEval] Skip uninitialized non-nullable locals in partial evaluation #9280

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

Merged
tlively merged 2 commits into from
Oct 20, 2026
Merged

[CtorEval] Skip uninitialized non-nullable locals in partial evaluation #9280

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
3fd8d36
[CtorEval] Skip uninitialized non-nullable locals in partial evaluation
tlively Oct 19, 2026
13c1543
no quadratic
tlively Oct 20, 2026
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
22 changes: 13 additions & 9 deletions src/tools/wasm-ctor-eval.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1329,17 +1329,21 @@ EvalCtorOutcome evalCtor(EvallingModuleRunner& instance,
auto* copyBody =
builder.blockify(ExpressionManipulator::copy(func->body, wasm));

// Remove the items we've evalled.
for (Index i = 0; i < successes; i++) {
copyBody->list[i] = builder.makeNop();
}

// Put the local sets at the front of the function body.
auto* setsBlock = builder.makeBlock();
// Replace the items we've evalled with the local sets at the front of the
// function body. Skip uninitialized non-nullable locals, whose default
// null value in the interpreter is not a valid subtype of the local's
// type.
std::vector<Expression*> newList;
newList.reserve(localExprs.size() + copyBody->list.size() - successes);
for (Index i = 0; i < localExprs.size(); ++i) {
setsBlock->list.push_back(builder.makeLocalSet(i, localExprs[i]));
if (Type::isSubType(localExprs[i]->type, func->getLocalType(i))) {
newList.push_back(builder.makeLocalSet(i, localExprs[i]));
}
}
copyBody = builder.makeSequence(setsBlock, copyBody, copyBody->type);
newList.insert(newList.end(),
copyBody->list.begin() + successes,
copyBody->list.end());
copyBody->list.set(newList);

// We may have return-called into a function with different parameter
// types, but we ultimately need to export a function with the original
Expand Down
80 changes: 76 additions & 4 deletions test/lit/ctor-eval/materialize-null-local.wast
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,12 +1,22 @@
;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.

;; RUN: wasm-ctor-eval %s -all --ctors=test --kept-exports=test --ignore-external-input -S -o - \
;; RUN: wasm-ctor-eval %s -all --ctors=test,non_nullable --kept-exports=test,non_nullable --ignore-external-input -S -o - \
;; RUN: | filecheck %s

;; Check that materializing a non-data null local, which at time of writing uses
;; Builder::makeConstantExpression, does not trigger an assertion failure.

(module
;; CHECK: (type $struct (struct))
(type $struct (struct))

;; CHECK: (type $1 (func (param externref)))

;; CHECK: (type $2 (func (result (ref $struct))))

;; CHECK: (import "env" "g" (global $g i32))
(import "env" "g" (global $g i32))

(func $test (export "test") (param $0 externref)
(local $3 anyref)
(local.set $3
Expand All @@ -15,12 +25,74 @@
)
)
)

(func $non_nullable (export "non_nullable") (result (ref $struct))
;; Partially evaluate the first statement, then stop on the imported global.
;; Do not emit an invalid (local.set $unset (ref.null none)) for the
;; uninitialized non-nullable local, and ensure the initialized non-nullable
;; local $init structurally dominates its use in the remaining body.
(local $init (ref $struct))
(local $unset (ref $struct))
(local.set $init
(struct.new $struct)
)
(if
(global.get $g)
(then
(return
(local.get $init)
)
)
)
(local.set $unset
(struct.new $struct)
)
(if
(global.get $g)
(then
(local.set $unset
(local.get $init)
)
)
)
(local.get $unset)
)
)
;; CHECK: (type $0 (func (param externref)))
;; CHECK: (global $ctor-eval$global (ref (exact $struct)) (struct.new_default $struct))

;; CHECK: (export "test" (func $test_1))
;; CHECK: (export "test" (func $test_2))

;; CHECK: (func $test_1 (type $0) (param $0 externref)
;; CHECK: (export "non_nullable" (func $non_nullable_3))

;; CHECK: (func $test_2 (type $1) (param $0 externref)
;; CHECK-NEXT: (local $3 anyref)
;; CHECK-NEXT: (nop)
;; CHECK-NEXT: )

;; CHECK: (func $non_nullable_3 (type $2) (result (ref $struct))
;; CHECK-NEXT: (local $0 (ref (exact $struct)))
;; CHECK-NEXT: (local $1 (ref (exact $struct)))
;; CHECK-NEXT: (local.set $0
;; CHECK-NEXT: (global.get $ctor-eval$global)
;; CHECK-NEXT: )
;; CHECK-NEXT: (if
;; CHECK-NEXT: (global.get $g)
;; CHECK-NEXT: (then
;; CHECK-NEXT: (return
;; CHECK-NEXT: (local.get $0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (local.set $1
;; CHECK-NEXT: (struct.new_default $struct)
;; CHECK-NEXT: )
;; CHECK-NEXT: (if
;; CHECK-NEXT: (global.get $g)
;; CHECK-NEXT: (then
;; CHECK-NEXT: (local.set $1
;; CHECK-NEXT: (local.get $0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (local.get $1)
;; CHECK-NEXT: )
Loading