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break and continue in a for await body, and nested for await (#502) #505

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Merged
ASDAlexander77 merged 1 commit into from
Oct 5, 2026
Merged

break and continue in a for await body, and nested for await (#502) #505

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65 changes: 6 additions & 59 deletions tslang/lib/TypeScript/MLIRGenStatements.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -788,8 +788,6 @@ namespace mlirgen

auto location = loc(forStatementAST);

auto hasAwait = InternalFlags::ForAwait == (forStatementAST->internalFlags & InternalFlags::ForAwait);

// initializer
// TODO: why do we have ForInitialier
if (isExpression(forStatementAST->initializer))
Expand Down Expand Up @@ -851,63 +849,12 @@ namespace mlirgen

// body
builder.setInsertionPointToStart(&forOp.getBody().front());
if (hasAwait)
{
if (forStatementAST->statement == SyntaxKind::Block)
{
auto firstStatement = forStatementAST->statement.as<ts::Block>()->statements.front();
auto result = mlirGen(firstStatement, loopGenContext);
EXIT_IF_FAILED(result)
}

// TODO: we need to strip metadata to fix issue with debug info
// async body
auto isFailed = false;
auto asyncExecOp = builder.create<mlir::async::ExecuteOp>(
stripMetadata(location), mlir::TypeRange{}, mlir::ValueRange{}, mlir::ValueRange{},
[&](mlir::OpBuilder &builder, mlir::Location location, mlir::ValueRange values) {
GenContext execOpBodyGenContext(loopGenContext);
DITableScopeT debugAsyncCodeScope(debugScope);
MLIRDebugInfoHelper mdi(builder, debugScope);

// TODO: temp hack to break wrong chain on scopes because 'await' create extra function wrap
mdi.clearDebugScope();
mdi.setLexicalBlock(location);

if (forStatementAST->statement == SyntaxKind::Block)
{
if (mlir::failed(mlirGen(forStatementAST->statement.as<ts::Block>(), execOpBodyGenContext, 1)))
{
isFailed = true;
}
}
else
{
if (mlir::failed(mlirGen(forStatementAST->statement, execOpBodyGenContext)))
{
isFailed = true;
}
}

builder.create<mlir::async::YieldOp>(location, mlir::ValueRange{});
});

if (isFailed)
{
return mlir::failure();
}

// One iteration at a time, as `for await` runs its body: the next value is asked for only
// once this body is done. Each body was added to a group awaited after the loop, so the
// bodies ran as concurrent tasks - interleaved, losing each other's writes (#498).
builder.create<mlir::async::AwaitOp>(location, asyncExecOp.getToken());
}
else
{
// default
auto result = mlirGen(forStatementAST->statement, loopGenContext);
EXIT_IF_FAILED(result)
}
// A `for await` body is generated in the loop as any other: an `await` in it makes its own
// async.execute and waits for it, so one iteration runs at a time (#498). Generated inside an
// async.execute of its own, a `break` or `continue` in it had no loop in its region, and a
// nested `for await` crashed the compiler (#502).
auto bodyResult = mlirGen(forStatementAST->statement, loopGenContext);
EXIT_IF_FAILED(bodyResult)

builder.create<mlir_ts::ResultOp>(location);

Expand Down
3 changes: 3 additions & 0 deletions tslang/test/tester/CMakeLists.txt
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Expand Up @@ -354,6 +354,7 @@ tslang_add_test(NAME test-compile-00-record-variable-to-class COMMAND test-runne
tslang_add_test(NAME test-compile-00-array-insert-functions COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00array_insert_functions.ts")
tslang_add_test(NAME test-compile-00-await-void COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00await_void.ts")
tslang_add_test(NAME test-compile-00-for-await-sequential COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00for_await_sequential.ts")
tslang_add_test(NAME test-compile-00-for-await-control COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00for_await_control.ts")
tslang_add_test(NAME test-compile-00-const-record-owned-fields COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00const_record_owned_fields.ts")
tslang_add_test(NAME test-compile-00-array-length-valid COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00array_length_valid.ts")
tslang_add_test(NAME test-compile-00-string-view-copy COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00string_view_copy.ts")
Expand Down Expand Up @@ -865,6 +866,7 @@ tslang_add_test(NAME test-jit-00-record-variable-to-class COMMAND test-runner -j
tslang_add_test(NAME test-jit-00-array-insert-functions COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00array_insert_functions.ts")
tslang_add_test(NAME test-jit-00-await-void COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00await_void.ts")
tslang_add_test(NAME test-jit-00-for-await-sequential COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00for_await_sequential.ts")
tslang_add_test(NAME test-jit-00-for-await-control COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00for_await_control.ts")
tslang_add_test(NAME test-jit-00-const-record-owned-fields COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00const_record_owned_fields.ts")
tslang_add_test(NAME test-jit-00-array-length-valid COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00array_length_valid.ts")
tslang_add_test(NAME test-jit-00-string-view-copy COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00string_view_copy.ts")
Expand Down Expand Up @@ -1705,6 +1707,7 @@ set(TSLANG_CORPUS
00array_insert_functions.ts
00await_void.ts
00for_await_sequential.ts
00for_await_control.ts
00const_record_owned_fields.ts
00array_length_valid.ts
00string_view_copy.ts
Expand Down
50 changes: 50 additions & 0 deletions tslang/test/tester/tests/00for_await_control.ts
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Original file line number Diff line number Diff line change
@@ -0,0 +1,50 @@
// `break` and `continue` in a `for await` body, and a `for await` nested in another (#502): the
// body was generated in an async.execute region of its own, where a `break` had no loop to leave,
// and the compiler crashed.
let log = "";
async function* numbers() {
yield 1;
yield 2;
yield 3;
yield 4;
}
async function* letters() {
yield "a";
yield "b";
}
async function note(s: string) {
log += s;
}
async function main() {
for await (const x of numbers()) {
if (x == 3) break;
log += x;
}
assert(log == "12", "break");

log = "";
for await (const x of numbers()) {
if (x == 2) continue;
log += x;
}
assert(log == "134", "continue");

log = "";
for await (const x of numbers()) {
for await (const y of letters()) {
log += x + y;
}
}
assert(log == "1a1b2a2b3a3b4a4b", "nested");

log = "";
for await (const x of numbers()) {
await note("<" + x);
if (x == 2) continue;
if (x == 4) break;
await note(">");
}
assert(log == "<1><2<3><4", "awaits, continue and break");

print("done.");
}
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