This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG320e4efe99d3: [C++20] [Coroutines] Mark coroutine done if
unhandled_exception throws (authored by ChuanqiXu).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D115219/new/
https://reviews.llvm.org/D115219
Files:
llvm/docs/Coroutines.rst
llvm/lib/Transforms/Coroutines/CoroSplit.cpp
llvm/test/Transforms/Coroutines/coro-split-eh-00.ll
llvm/test/Transforms/Coroutines/coro-split-eh-01.ll
Index: llvm/test/Transforms/Coroutines/coro-split-eh-01.ll
===================================================================
--- llvm/test/Transforms/Coroutines/coro-split-eh-01.ll
+++ llvm/test/Transforms/Coroutines/coro-split-eh-01.ll
@@ -61,6 +61,9 @@
; CHECK: lpad:
; CHECK-NEXT: %tok = cleanuppad within none []
; CHECK-NEXT: call void @print(i32 2)
+; Checks that the coroutine would be marked as done if it exits in unwinding path.
+; CHECK-NEXT: %[[RESUME_ADDR:.+]] = getelementptr inbounds %[[FRAME_TY:.+]], %[[FRAME_TY]]* %FramePtr, i32 0, i32 0
+; CHECK-NEXT: store void (%[[FRAME_TY]]*)* null, void (%[[FRAME_TY]]*)** %[[RESUME_ADDR]], align 8
; CHECK-NEXT: cleanupret from %tok unwind to caller
declare i8* @llvm.coro.free(token, i8*)
Index: llvm/test/Transforms/Coroutines/coro-split-eh-00.ll
===================================================================
--- llvm/test/Transforms/Coroutines/coro-split-eh-00.ll
+++ llvm/test/Transforms/Coroutines/coro-split-eh-00.ll
@@ -67,6 +67,9 @@
; CHECK-NEXT: %lpval = landingpad { i8*, i32 }
; CHECK-NEXT: cleanup
; CHECK-NEXT: call void @print(i32 2)
+; Checks that the coroutine would be marked as done if it exits in unwinding path.
+; CHECK-NEXT: %[[RESUME_ADDR:.+]] = getelementptr inbounds %[[FRAME_TY:.+]], %[[FRAME_TY]]* %FramePtr, i32 0, i32 0
+; CHECK-NEXT: store void (%[[FRAME_TY]]*)* null, void (%[[FRAME_TY]]*)** %[[RESUME_ADDR]], align 8
; CHECK-NEXT: resume { i8*, i32 } %lpval
declare i8* @llvm.coro.free(token, i8*)
Index: llvm/lib/Transforms/Coroutines/CoroSplit.cpp
===================================================================
--- llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -280,6 +280,27 @@
BB->getTerminator()->eraseFromParent();
}
+// Mark a coroutine as done, which implies that the coroutine is finished and
+// never get resumed.
+//
+// In resume-switched ABI, the done state is represented by storing zero in
+// ResumeFnAddr.
+//
+// NOTE: We couldn't omit the argument `FramePtr`. It is necessary because the
+// pointer to the frame in splitted function is not stored in `Shape`.
+static void markCoroutineAsDone(IRBuilder<> &Builder, const coro::Shape &Shape,
+ Value *FramePtr) {
+ assert(
+ Shape.ABI == coro::ABI::Switch &&
+ "markCoroutineAsDone is only supported for Switch-Resumed ABI for now.");
+ auto *GepIndex = Builder.CreateStructGEP(
+ Shape.FrameTy, FramePtr, coro::Shape::SwitchFieldIndex::Resume,
+ "ResumeFn.addr");
+ auto *NullPtr = ConstantPointerNull::get(cast<PointerType>(
+ Shape.FrameTy->getTypeAtIndex(coro::Shape::SwitchFieldIndex::Resume)));
+ Builder.CreateStore(NullPtr, GepIndex);
+}
+
/// Replace an unwind call to llvm.coro.end.
static void replaceUnwindCoroEnd(AnyCoroEndInst *End, const coro::Shape &Shape,
Value *FramePtr, bool InResume,
@@ -288,10 +309,18 @@
switch (Shape.ABI) {
// In switch-lowering, this does nothing in the main function.
- case coro::ABI::Switch:
+ case coro::ABI::Switch: {
+ // In C++'s specification, the coroutine should be marked as done
+ // if promise.unhandled_exception() throws. The frontend will
+ // call coro.end(true) along this path.
+ //
+ // FIXME: We should refactor this once there is other language
+ // which uses Switch-Resumed style other than C++.
+ markCoroutineAsDone(Builder, Shape, FramePtr);
if (!InResume)
return;
break;
+ }
// In async lowering this does nothing.
case coro::ABI::Async:
break;
@@ -364,13 +393,9 @@
auto *Save = S->getCoroSave();
Builder.SetInsertPoint(Save);
if (S->isFinal()) {
- // Final suspend point is represented by storing zero in ResumeFnAddr.
- auto *GepIndex = Builder.CreateStructGEP(FrameTy, FramePtr,
- coro::Shape::SwitchFieldIndex::Resume,
- "ResumeFn.addr");
- auto *NullPtr = ConstantPointerNull::get(cast<PointerType>(
- FrameTy->getTypeAtIndex(coro::Shape::SwitchFieldIndex::Resume)));
- Builder.CreateStore(NullPtr, GepIndex);
+ // The coroutine should be marked done if it reaches the final suspend
+ // point.
+ markCoroutineAsDone(Builder, Shape, FramePtr);
} else {
auto *GepIndex = Builder.CreateStructGEP(
FrameTy, FramePtr, Shape.getSwitchIndexField(), "index.addr");
Index: llvm/docs/Coroutines.rst
===================================================================
--- llvm/docs/Coroutines.rst
+++ llvm/docs/Coroutines.rst
@@ -1377,17 +1377,23 @@
``cleanupret from %tok unwind to caller`` before
the `coro.end`_ intrinsic and will remove the rest of the block.
+In the unwind path (when the argument is `true`), `coro.end` will mark the coroutine
+as done, making it undefined behavior to resume the coroutine again and causing
+`llvm.coro.done` to return `true`. This is not necessary in the normal path because
+the coroutine will already be marked as done by the final suspend.
+
The following table summarizes the handling of `coro.end`_ intrinsic.
-+--------------------------+-------------------+-------------------------------+
-| | In Start Function | In Resume/Destroy Functions |
-+--------------------------+-------------------+-------------------------------+
-|unwind=false | nothing |``ret void`` |
-+------------+-------------+-------------------+-------------------------------+
-| | WinEH | nothing |``cleanupret unwind to caller``|
-|unwind=true +-------------+-------------------+-------------------------------+
-| | Landingpad | nothing | nothing |
-+------------+-------------+-------------------+-------------------------------+
++--------------------------+------------------------+-------------------------------+
+| | In Start Function | In Resume/Destroy Functions |
++--------------------------+------------------------+-------------------------------+
+|unwind=false | nothing |``ret void`` |
++------------+-------------+------------------------+-------------------------------+
+| | WinEH | mark coroutine as done |``cleanupret unwind to caller``|
+| | | |mark coroutine done |
+|unwind=true +-------------+------------------------+-------------------------------+
+| | Landingpad | mark coroutine as done | mark coroutine done |
++------------+-------------+------------------------+-------------------------------+
'llvm.coro.end.async' Intrinsic
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