From: Erich Keane <erich.keane@intel.com>
Date: Thu, 27 Jul 2017 16:28:20 +0000 (+0000)
Subject: Fix double destruction of objects when OpenMP construct is canceled
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9b26b17bc491d3aab37b592097c8831fecc21fe6;p=clang

Fix double destruction of objects when OpenMP construct is canceled

When an omp for loop is canceled the constructed objects are being destructed
twice.

It looks like the desired code is:

{

  Obj o;
  If (cancelled) branch-through-cleanups to cancel.exit.

}
[cleanups]
cancel.exit:

__kmpc_for_static_fini
br cancel.cont (*)

cancel.cont:

__kmpc_barrier
return

The problem seems to be the branch to cancel.cont is currently also going
through the cleanups calling them again. This change just does a direct branch
instead.

Patch By: michael.p.rice@intel.com

Differential Revision: https://reviews.llvm.org/D35854


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@309288 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 2e31be8c68..fed92a41a9 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -1116,7 +1116,7 @@ private:
         auto IP = CGF.Builder.saveAndClearIP();
         CGF.EmitBlock(Stack.back().ExitBlock.getBlock());
         CodeGen(CGF);
-        CGF.EmitBranchThroughCleanup(Stack.back().ContBlock);
+        CGF.EmitBranch(Stack.back().ContBlock.getBlock());
         CGF.Builder.restoreIP(IP);
         Stack.back().HasBeenEmitted = true;
       }
diff --git a/test/OpenMP/cancel_codegen_cleanup.cpp b/test/OpenMP/cancel_codegen_cleanup.cpp
new file mode 100644
index 0000000000..5a297bd377
--- /dev/null
+++ b/test/OpenMP/cancel_codegen_cleanup.cpp
@@ -0,0 +1,46 @@
+// RUN: %clang_cc1 -std=c++11 -fopenmp -fopenmp-version=45 -triple x86_64-apple-darwin13.4.0 -emit-llvm -o - %s | FileCheck %s
+
+//CHECK: call i32 @__kmpc_cancel
+//CHECK: br {{.*}}label %[[EXIT:[^,].+]], label %[[CONTINUE:.+]]
+//CHECK: [[EXIT]]:
+//CHECK: store i32 [[EXIT_SLOT:[0-9]+]]
+//CHECK: br label %[[CLEANUP:.+]]
+//CHECK: [[CONTINUE]]:
+//CHECK: store i32 [[CONT_SLOT:[0-9]+]],
+//CHECK: br label %[[CLEANUP]]
+//CHECK: [[CLEANUP]]:
+//CHECK-NEXT: call void @_ZN3ObjD1Ev
+//CHECK: switch i32{{.*}}, label %[[UNREACHABLE:.+]] [
+//CHECK:   i32 [[CONT_SLOT]], label %[[CLEANUPCONT:.+]]
+//CHECK:   i32 [[EXIT_SLOT]], label %[[CANCELEXIT:.+]]
+//CHECK-NEXT: ]
+//CHECK: [[CLEANUPCONT]]:
+//CHECK: br label %[[CANCELCONT:.+]]
+//CHECK: [[CANCELCONT]]:
+//CHECK-NEXT: call void @__kmpc_barrier(
+//CHECK-NEXT: ret void
+//CHECK: [[UNREACHABLE]]:
+//CHECK-NEXT: unreachable
+//CHECK-NEXT: }
+
+struct Obj {
+  int a; Obj(); Obj(const Obj& r) = delete; Obj &operator=(const Obj& r);
+  ~Obj();
+};
+ 
+void foo() {
+  int i,count = 0;
+  Obj obj;
+
+  #pragma omp parallel private(i) num_threads(1)
+  {
+      #pragma omp for reduction(+:count) lastprivate(obj)
+      for (i=0; i<1000; i++) {
+            if(i==100) {
+                obj.a = 100;
+                #pragma omp cancel for
+            }
+            count++;
+        }
+    }
+}