r299510 - [coroutines] Add coro.end handling

Gor Nishanov via cfe-commits cfe-commits at lists.llvm.org
Tue Apr 4 21:55:03 PDT 2017


Author: gornishanov
Date: Tue Apr  4 23:55:03 2017
New Revision: 299510

URL: http://llvm.org/viewvc/llvm-project?rev=299510&view=rev
Log:
[coroutines] Add coro.end handling

Summary:
For WinEH, We add a funclet bundle to a coro.end call, so that CoroSplit in LLVM can replace it with cleanup ret and cut the rest out.
For landing pad, we add a branch to resume block if coro.end returns true.

LLVM Part: https://reviews.llvm.org/D25445

Reviewers: majnemer

Reviewed By: majnemer

Subscribers: EricWF, cfe-commits, rsmith, mehdi_amini

Differential Revision: https://reviews.llvm.org/D25444

Added:
    cfe/trunk/test/CodeGenCoroutines/coro-eh-cleanup.cpp
Modified:
    cfe/trunk/lib/CodeGen/CGCoroutine.cpp

Modified: cfe/trunk/lib/CodeGen/CGCoroutine.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCoroutine.cpp?rev=299510&r1=299509&r2=299510&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGCoroutine.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGCoroutine.cpp Tue Apr  4 23:55:03 2017
@@ -215,6 +215,43 @@ void CodeGenFunction::EmitCoreturnStmt(C
   EmitBranchThroughCleanup(CurCoro.Data->FinalJD);
 }
 
+// For WinEH exception representation backend need to know what funclet coro.end
+// belongs to. That information is passed in a funclet bundle.
+static SmallVector<llvm::OperandBundleDef, 1>
+getBundlesForCoroEnd(CodeGenFunction &CGF) {
+  SmallVector<llvm::OperandBundleDef, 1> BundleList;
+
+  if (llvm::Instruction *EHPad = CGF.CurrentFuncletPad)
+    BundleList.emplace_back("funclet", EHPad);
+
+  return BundleList;
+}
+
+namespace {
+// We will insert coro.end to cut any of the destructors for objects that
+// do not need to be destroyed once the coroutine is resumed.
+// See llvm/docs/Coroutines.rst for more details about coro.end.
+struct CallCoroEnd final : public EHScopeStack::Cleanup {
+  void Emit(CodeGenFunction &CGF, Flags flags) override {
+    auto &CGM = CGF.CGM;
+    auto *NullPtr = llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
+    llvm::Function *CoroEndFn = CGM.getIntrinsic(llvm::Intrinsic::coro_end);
+    // See if we have a funclet bundle to associate coro.end with. (WinEH)
+    auto Bundles = getBundlesForCoroEnd(CGF);
+    auto *CoroEnd = CGF.Builder.CreateCall(
+        CoroEndFn, {NullPtr, CGF.Builder.getTrue()}, Bundles);
+    if (Bundles.empty()) {
+      // Otherwise, (landingpad model), create a conditional branch that leads
+      // either to a cleanup block or a block with EH resume instruction.
+      auto *ResumeBB = CGF.getEHResumeBlock(/*cleanup=*/true);
+      auto *CleanupContBB = CGF.createBasicBlock("cleanup.cont");
+      CGF.Builder.CreateCondBr(CoroEnd, ResumeBB, CleanupContBB);
+      CGF.EmitBlock(CleanupContBB);
+    }
+  }
+};
+}
+
 namespace {
 // Make sure to call coro.delete on scope exit.
 struct CallCoroDelete final : public EHScopeStack::Cleanup {
@@ -273,6 +310,8 @@ void CodeGenFunction::EmitCoroutineBody(
 
     EmitStmt(S.getPromiseDeclStmt());
 
+    EHStack.pushCleanup<CallCoroEnd>(EHCleanup);
+
     CurCoro.Data->FinalJD = getJumpDestInCurrentScope(FinalBB);
 
     // FIXME: Emit initial suspend and more before the body.
@@ -290,6 +329,8 @@ void CodeGenFunction::EmitCoroutineBody(
   }
 
   EmitBlock(RetBB);
+  llvm::Function *CoroEnd = CGM.getIntrinsic(llvm::Intrinsic::coro_end);
+  Builder.CreateCall(CoroEnd, {NullPtr, Builder.getFalse()});
 
   // FIXME: Emit return for the coroutine return object.
 }

Added: cfe/trunk/test/CodeGenCoroutines/coro-eh-cleanup.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCoroutines/coro-eh-cleanup.cpp?rev=299510&view=auto
==============================================================================
--- cfe/trunk/test/CodeGenCoroutines/coro-eh-cleanup.cpp (added)
+++ cfe/trunk/test/CodeGenCoroutines/coro-eh-cleanup.cpp Tue Apr  4 23:55:03 2017
@@ -0,0 +1,74 @@
+// RUN: %clang_cc1 -std=c++1z -fcoroutines-ts -triple=x86_64-pc-windows-msvc18.0.0 -emit-llvm %s -o - -fexceptions -fcxx-exceptions -disable-llvm-passes | FileCheck %s
+// RUN: %clang_cc1 -std=c++1z -fcoroutines-ts -triple=x86_64-unknown-linux-gnu -emit-llvm -o - %s -fexceptions -fcxx-exceptions -disable-llvm-passes | FileCheck --check-prefix=CHECK-LPAD %s
+
+namespace std::experimental {
+template <typename R, typename... T> struct coroutine_traits {
+  using promise_type = typename R::promise_type;
+};
+
+template <class Promise = void> struct coroutine_handle;
+
+template <> struct coroutine_handle<void> {
+  static coroutine_handle from_address(void *) noexcept;
+  coroutine_handle() = default;
+  template <class PromiseType>
+  coroutine_handle(coroutine_handle<PromiseType>) noexcept;
+};
+template <class Promise> struct coroutine_handle: coroutine_handle<void> {
+  coroutine_handle() = default;
+  static coroutine_handle from_address(void *) noexcept;
+};
+}
+
+struct suspend_always {
+  bool await_ready() noexcept;
+  void await_suspend(std::experimental::coroutine_handle<>) noexcept;
+  void await_resume() noexcept;
+};
+
+struct coro_t {
+  struct promise_type {
+    coro_t get_return_object() noexcept;
+    suspend_always initial_suspend() noexcept;
+    suspend_always final_suspend() noexcept;
+    void return_void() noexcept;
+    void unhandled_exception() noexcept;
+  };
+};
+
+struct Cleanup { ~Cleanup(); };
+void may_throw();
+
+coro_t f() {
+  Cleanup x;
+  may_throw();
+  co_return;
+}
+
+// CHECK: @"\01?f@@YA?AUcoro_t@@XZ"(
+// CHECK:   invoke void @"\01?may_throw@@YAXXZ"()
+// CHECK:       to label %[[CONT:.+]] unwind label %[[EHCLEANUP:.+]]
+// CHECK: [[EHCLEANUP]]:
+// CHECK:   %[[INNERPAD:.+]] = cleanuppad within none []
+// CHECK:   call void @"\01??_DCleanup@@QEAAXXZ"(
+// CHECK:   cleanupret from %[[INNERPAD]] unwind label %[[COROENDBB:.+]]
+// CHECK: [[COROENDBB]]:
+// CHECK-NEXT: %[[CLPAD:.+]] = cleanuppad within none
+// CHECK-NEXT: call i1 @llvm.coro.end(i8* null, i1 true) [ "funclet"(token %[[CLPAD]]) ]
+// CHECK-NEXT: cleanupret from %[[CLPAD]] unwind label
+
+// CHECK-LPAD: @_Z1fv(
+// CHECK-LPAD:   invoke void @_Z9may_throwv()
+// CHECK-LPAD:       to label %[[CONT:.+]] unwind label %[[EHCLEANUP:.+]]
+// CHECK-LPAD: [[EHCLEANUP]]:
+// CHECK-LPAD:    landingpad { i8*, i32 }
+// CHECK-LPAD:          cleanup
+// CHECK-LPAD:   call void @_ZN7CleanupD1Ev(
+// CHECK-LPAD:   %[[I1RESUME:.+]] = call i1 @llvm.coro.end(i8* null, i1 true)
+// CHECK-LPAD:   br i1  %[[I1RESUME]], label %[[EHRESUME:.+]], label
+// CHECK-LPAD: [[EHRESUME]]:
+// CHECK-LPAD-NEXT:  %[[exn:.+]] = load i8*, i8** %exn.slot, align 8
+// CHECK-LPAD-NEXT:  %[[sel:.+]] = load i32, i32* %ehselector.slot, align 4
+// CHECK-LPAD-NEXT:  %[[val1:.+]] = insertvalue { i8*, i32 } undef, i8* %[[exn]], 0
+// CHECK-LPAD-NEXT:  %[[val2:.+]] = insertvalue { i8*, i32 } %[[val1]], i32 %[[sel]], 1
+// CHECK-LPAD-NEXT:  resume { i8*, i32 } %[[val2]]




More information about the cfe-commits mailing list