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allow async on the top level #527

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allow async on the top level #527

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e9bafb9
allow async on the top level
mschwarzl Sep 9, 2025
87a7ec8
Add brackets
mschwarzl Sep 9, 2025
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7 changes: 2 additions & 5 deletions Sources/Fuzzilli/Compiler/Compiler.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -1160,13 +1160,10 @@ public class JavaScriptCompiler {
fatalError("V8IntrinsicIdentifiers must be handled as part of their surrounding CallExpression")

case .awaitExpression(let awaitExpression):
// TODO await is also allowed at the top level of a module
if !contextAnalyzer.context.contains(.asyncFunction) {
throw CompilerError.invalidNodeError("`await` is currently only supported in async functions")
}
// Await is also allowed at the top level of a module
// workerd requires that support
let argument = try compileExpression(awaitExpression.argument)
return emit(Await(), withInputs: [argument]).output

}
}

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2 changes: 1 addition & 1 deletion Sources/Fuzzilli/Compiler/Parser/parser.js
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Expand Up @@ -34,7 +34,7 @@ function tryReadFile(path) {

// Parse the given JavaScript script and return an AST compatible with Fuzzilli's protobuf-based AST format.
function parse(script, proto) {
let ast = Parser.parse(script, { plugins: ["v8intrinsic"] });
let ast = Parser.parse(script, { allowAwaitOutsideFunction: true, plugins: ["topLevelAwait","v8intrinsic"] });

function assertNoError(err) {
if (err) throw err;
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9 changes: 6 additions & 3 deletions Sources/Fuzzilli/FuzzIL/Code.swift
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Expand Up @@ -239,9 +239,12 @@ public struct Code: Collection {
throw FuzzilliError.codeVerificationError("variable \(input) is not visible anymore")
}
}

guard instr.op.requiredContext.isSubset(of: contextAnalyzer.context) else {
throw FuzzilliError.codeVerificationError("operation \(instr.op.name) inside an invalid context")

// allow top-level await
if !(instr.op is Await) {
guard instr.op.requiredContext.isSubset(of: contextAnalyzer.context) else {
throw FuzzilliError.codeVerificationError("operation \(instr.op.name) inside an invalid context")
}
}

// Ensure that the instruction exists in the right context
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