Add a new warning, -Wover-aligned, which detects attempts to use the default

allocator to construct an object which declares more alignment than the default
allocator actually provides. Fixes PR9527!

llvm-svn: 148857

1 files changed, 20 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/warn-new-overaligned-3.cpp b/clang/test/SemaCXX/warn-new-overaligned-3.cpp
new file mode 100644
index 00000000000..f3b0cb7dd18
--- /dev/null
+++ b/clang/test/SemaCXX/warn-new-overaligned-3.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -Wover-aligned %s -isystem %S/Inputs -verify
+
+// This test ensures that we still get the warning even if we #include <new>
+// where the header here simulates <new>.
+#include <warn-new-overaligned-3.h>
+
+struct Test {
+  template <typename T>
+  struct SeparateCacheLines {
+    T data;
+  } __attribute__((aligned(256)));
+
+  SeparateCacheLines<int> high_contention_data[10];
+};
+
+void helper() {
+  Test t;
+  new Test;  // expected-warning {{type 'Test' requires 256 bytes of alignment and the default allocator only guarantees}}
+  new Test[10];  // expected-warning {{type 'Test' requires 256 bytes of alignment and the default allocator only guarantees}}
+}