https://github.com/tru updated https://github.com/llvm/llvm-project/pull/149013
>From ad9051049d4360a8409eb4c552ba92524a41c13b Mon Sep 17 00:00:00 2001 From: Yuxuan Chen <y...@fb.com> Date: Tue, 15 Jul 2025 15:02:32 -0700 Subject: [PATCH] [Clang] Fix FE crash during CGCoroutine GRO Alloca Emission (#148962) Fixes: https://github.com/llvm/llvm-project/issues/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 c36156de45a0f5e24e7a4ee2259c3302ea814785) --- clang/lib/CodeGen/CGCoroutine.cpp | 14 +++++++---- clang/test/CodeGenCoroutines/coro-gro.cpp | 29 ++++++++++++++++++++++- 2 files changed, 37 insertions(+), 6 deletions(-) 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]] = !{} _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
