From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Thu, 11 May 2017 00:17:17 +0000 (+0000)
Subject: PR22877: When constructing an array via a constructor with a default argument
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=1ac0f201387d84ebcf90968a7276c120c0fe7688;p=clang

PR22877: When constructing an array via a constructor with a default argument
in list-initialization, run cleanups for the default argument after each
iteration of the initialization loop.

We previously only ran the destructor for any temporary once, at the end of the
complete loop, rather than once per iteration!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302750 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index 49bbb4808e..a05a088f09 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -512,12 +512,20 @@ void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType,
     currentElement->addIncoming(element, entryBB);
 
     // Emit the actual filler expression.
-    LValue elementLV =
-      CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType);
-    if (filler)
-      EmitInitializationToLValue(filler, elementLV);
-    else
-      EmitNullInitializationToLValue(elementLV);
+    {
+      // C++1z [class.temporary]p5:
+      //   when a default constructor is called to initialize an element of
+      //   an array with no corresponding initializer [...] the destruction of
+      //   every temporary created in a default argument is sequenced before
+      //   the construction of the next array element, if any
+      CodeGenFunction::RunCleanupsScope CleanupsScope(CGF);
+      LValue elementLV =
+        CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType);
+      if (filler)
+        EmitInitializationToLValue(filler, elementLV);
+      else
+        EmitNullInitializationToLValue(elementLV);
+    }
 
     // Move on to the next element.
     llvm::Value *nextElement =
diff --git a/test/CodeGenCXX/array-default-argument.cpp b/test/CodeGenCXX/array-default-argument.cpp
new file mode 100644
index 0000000000..1fba485f37
--- /dev/null
+++ b/test/CodeGenCXX/array-default-argument.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -emit-llvm -o - %s -triple %itanium_abi_triple | FileCheck %s
+// RUN: %clang_cc1 -emit-llvm -o - %s -triple %itanium_abi_triple -fexceptions -fcxx-exceptions | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-EH
+
+struct A {
+  A();
+  ~A();
+};
+
+struct B {
+  B(A = A());
+  ~B();
+};
+
+void f();
+// CHECK-LABEL: define void @_Z1gv()
+void g() {
+  // CHECK: br label %[[LOOP:.*]]
+
+  // [[LOOP]]:
+  // CHECK: {{call|invoke}} void @_ZN1AC1Ev([[TEMPORARY:.*]])
+  // CHECK-EH:  unwind label %[[PARTIAL_ARRAY_LPAD:.*]]
+  // CHECK: {{call|invoke}} void @_ZN1BC1E1A({{.*}}, [[TEMPORARY]])
+  // CHECK-EH:  unwind label %[[A_AND_PARTIAL_ARRAY_LPAD:.*]]
+  // CHECK: {{call|invoke}} void @_ZN1AD1Ev([[TEMPORARY]])
+  // CHECK-EH:  unwind label %[[PARTIAL_ARRAY_LPAD]]
+  // CHECK: getelementptr {{.*}}, i{{[0-9]*}} 1
+  // CHECK: icmp eq
+  // CHECK: br i1 {{.*}} label %[[LOOP]]
+  B b[5];
+
+  // CHECK: {{call|invoke}} void @_Z1fv()
+  f();
+
+  // CHECK-NOT: @_ZN1AD1Ev(
+  // CHECK: {{call|invoke}} void @_ZN1BD1Ev(
+}