Add a hack to silence warnings about failing to return from functions after

a temporary with a noreturn destructor has been created. Fixes PR6884 for now.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@104000 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 30 insertions, 0 deletions

diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp
index 21dd40b32e..448d16116a 100644
--- a/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/lib/Sema/AnalysisBasedWarnings.cpp
@@ -167,6 +167,19 @@ static ControlFlowKind CheckFallThrough(AnalysisContext &AC) {
         }
       }
     }
+    // FIXME: Remove this hack once temporaries and their destructors are
+    // modeled correctly by the CFG.
+    if (CXXExprWithTemporaries *E = dyn_cast<CXXExprWithTemporaries>(S)) {
+      for (unsigned I = 0, N = E->getNumTemporaries(); I != N; ++I) {
+        const FunctionDecl *FD = E->getTemporary(I)->getDestructor();
+        if (FD->hasAttr<NoReturnAttr>() ||
+            FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) {
+          NoReturnEdge = true;
+          HasFakeEdge = true;
+          break;
+        }
+      }
+    }
     // FIXME: Add noreturn message sends.
     if (NoReturnEdge == false)
       HasPlainEdge = true;
diff --git a/test/SemaCXX/return-noreturn.cpp b/test/SemaCXX/return-noreturn.cpp
new file mode 100644
index 0000000000..9242d1240a
--- /dev/null
+++ b/test/SemaCXX/return-noreturn.cpp
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 %s -fsyntax-only -verify -Wmissing-noreturn -Wno-unreachable-code
+
+// A destructor may be marked noreturn and should still influence the CFG.
+namespace PR6884 {
+  struct abort_struct {
+    abort_struct() {} // Make this non-POD so the destructor is invoked.
+    ~abort_struct() __attribute__((noreturn));
+  };
+
+  int f() {
+    abort_struct();
+  }
+
+  int f2() {
+    abort_struct s;
+  } // expected-warning{{control reaches end of non-void function}}
+}