release/21.x: [Clang] Fix FE crash during CGCoroutine GRO Alloca Emission (#148962) #149013
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@bcardosolopes What do you think about merging this PR to the release branch? |
llvmbot
added
clang
|
@llvm/pr-subscribers-clang @llvm/pr-subscribers-coroutines Author: None (llvmbot) ChangesBackport c36156d Requested by: @efriedma-quic Full diff: https://github.com/llvm/llvm-project/pull/149013.diff 2 Files Affected:
diff --git a/clang/lib/CodeGen/CGCoroutine.cpp b/clang/lib/CodeGen/CGCoroutine.cpp
index 0fc488e98aaf0..117ef3d16e21b 100644
--- a/clang/lib/CodeGen/CGCoroutine.cpp
+++ b/clang/lib/CodeGen/CGCoroutine.cpp
@@ -707,11 +707,15 @@ struct GetReturnObjectManager {
Builder.CreateStore(Builder.getFalse(), GroActiveFlag);
GroEmission = CGF.EmitAutoVarAlloca(*GroVarDecl);
- auto *GroAlloca = dyn_cast_or_null<llvm::AllocaInst>(
- GroEmission.getOriginalAllocatedAddress().getPointer());
- assert(GroAlloca && "expected alloca to be emitted");
- GroAlloca->setMetadata(llvm::LLVMContext::MD_coro_outside_frame,
- llvm::MDNode::get(CGF.CGM.getLLVMContext(), {}));
+
+ if (!GroVarDecl->isNRVOVariable()) {
+ // NRVO variables don't have allocas and won't have the same issue.
+ auto *GroAlloca = dyn_cast_or_null<llvm::AllocaInst>(
+ GroEmission.getOriginalAllocatedAddress().getPointer());
+ assert(GroAlloca && "expected alloca to be emitted");
+ GroAlloca->setMetadata(llvm::LLVMContext::MD_coro_outside_frame,
+ llvm::MDNode::get(CGF.CGM.getLLVMContext(), {}));
+ }
// Remember the top of EHStack before emitting the cleanup.
auto old_top = CGF.EHStack.stable_begin();
diff --git a/clang/test/CodeGenCoroutines/coro-gro.cpp b/clang/test/CodeGenCoroutines/coro-gro.cpp
index b62134317cef2..037fd03349e76 100644
--- a/clang/test/CodeGenCoroutines/coro-gro.cpp
+++ b/clang/test/CodeGenCoroutines/coro-gro.cpp
@@ -106,4 +106,31 @@ invoker g() {
// CHECK: call void @_ZN7invoker15invoker_promise17get_return_objectEv({{.*}} %[[AggRes]]
co_return;
}
-// CHECK: ![[OutFrameMetadata]] = !{}
\ No newline at end of file
+
+namespace gh148953 {
+
+struct Task {
+ struct promise_type {
+ Task get_return_object();
+ std::suspend_always initial_suspend() { return {}; }
+ std::suspend_always final_suspend() noexcept { return {}; }
+ void return_void() {}
+ void unhandled_exception() {}
+ };
+ Task() {}
+ // Different from `invoker`, this Task is copy constructible.
+ Task(const Task&) {};
+};
+
+// NRVO on const qualified return type should work.
+// CHECK: define{{.*}} void @_ZN8gh1489537exampleEv({{.*}} sret(%"struct.gh148953::Task") align 1 %[[NrvoRes:.+]])
+const Task example() {
+ // CHECK: %[[ResultPtr:.+]] = alloca ptr
+ // CHECK: store ptr %[[NrvoRes]], ptr %[[ResultPtr]]
+ // CHECK: coro.init:
+ // CHECK: call void @_ZN8gh1489534Task12promise_type17get_return_objectEv({{.*}} %[[NrvoRes:.+]], {{.*}})
+ co_return;
+}
+
+} // namespace gh148953
+// CHECK: ![[OutFrameMetadata]] = !{}
|
|
@bcardosolopes can you review this for inclusion in the release branch? |
github-project-automation
bot
moved this from Needs Review
to Needs Merge
in LLVM Release Status
) Fixes: llvm#148953 Currently when coroutine return object type is const qualified, we don't do direct emission. The regular emission logic assumed that the auto var emission will always result in an `AllocaInst`. However, based on my findings, NRVO var emissions don't result in `AllocaInst`s. Therefore, this [assertion](https://github.com/llvm/llvm-project/blob/1a940bfff9176fb38a71b0045d7ae25df9a4ca7d/clang/lib/CodeGen/CGCoroutine.cpp#L712) will fail. Since the NRVOed returned object don't live on the coroutine frame, we won't have the problem of it outliving the coroutine frame, therefore, we can safely omit this metadata. (cherry picked from commit c36156d)
github-project-automation
bot
moved this from Needs Merge
to Done
in LLVM Release Status
|
@efriedma-quic (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Backport c36156d
Requested by: @efriedma-quic