Clean up the "non-POD memaccess" stuff some. This adds a properly named

diagnostic group to cover the cases where we have definitively bad
behavior: dynamic classes.

It also rips out the existing support for POD-based checking. This
didn't work well, and triggered too many false positives. I'm looking
into a possibly more principled way to warn on the fundamental buggy
construct here. POD-ness isn't the critical aspect anyways, so a clean
slate is better. This also removes some silliness from the code until
the new checks arrive.

llvm-svn: 132534

1 files changed, 70 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/warn-bad-memaccess.cpp b/clang/test/SemaCXX/warn-bad-memaccess.cpp
new file mode 100644
index 00000000000..e7d095f0edc
--- /dev/null
+++ b/clang/test/SemaCXX/warn-bad-memaccess.cpp
@@ -0,0 +1,70 @@
+// RUN: %clang_cc1 -fsyntax-only -Wdynamic-class-memaccess -verify %s
+
+extern "C" void *memset(void *, int, unsigned);
+extern "C" void *memmove(void *s1, const void *s2, unsigned n);
+extern "C" void *memcpy(void *s1, const void *s2, unsigned n);
+
+// Several types that should not warn.
+struct S1 {} s1;
+struct S2 { int x; } s2;
+struct S3 { float x, y; S1 s[4]; void (*f)(S1**); } s3;
+
+class C1 {
+  int x, y, z;
+public:
+  void foo() {}
+} c1;
+
+struct X1 { virtual void f(); } x1;
+struct X2 : virtual S1 {} x2;
+
+void test_warn() {
+  memset(&x1, 0, sizeof x1); // \
+      // expected-warning {{destination for this 'memset' call is a pointer to dynamic class}} \
+      // expected-note {{explicitly cast the pointer to silence this warning}}
+  memset(&x2, 0, sizeof x2); // \
+      // expected-warning {{destination for this 'memset' call is a pointer to dynamic class}} \
+      // expected-note {{explicitly cast the pointer to silence this warning}}
+
+  memmove(&x1, 0, sizeof x1); // \
+      // expected-warning{{destination for this 'memmove' call is a pointer to dynamic class}} \
+      // expected-note {{explicitly cast the pointer to silence this warning}}
+  memmove(0, &x1, sizeof x1); // \
+      // expected-warning{{source of this 'memmove' call is a pointer to dynamic class}} \
+      // expected-note {{explicitly cast the pointer to silence this warning}}
+  memcpy(&x1, 0, sizeof x1); // \
+      // expected-warning{{destination for this 'memcpy' call is a pointer to dynamic class}} \
+      // expected-note {{explicitly cast the pointer to silence this warning}}
+  memcpy(0, &x1, sizeof x1); // \
+      // expected-warning{{source of this 'memcpy' call is a pointer to dynamic class}} \
+      // expected-note {{explicitly cast the pointer to silence this warning}}
+}
+
+void test_nowarn(void *void_ptr) {
+  int i, *iptr;
+  float y;
+  char c;
+
+  memset(&i, 0, sizeof i);
+  memset(&iptr, 0, sizeof iptr);
+  memset(&y, 0, sizeof y);
+  memset(&c, 0, sizeof c);
+  memset(void_ptr, 0, 42);
+  memset(&s1, 0, sizeof s1);
+  memset(&s2, 0, sizeof s2);
+  memset(&s3, 0, sizeof s3);
+  memset(&c1, 0, sizeof c1);
+
+  // Unevaluated code shouldn't warn.
+  (void)sizeof memset(&x1, 0, sizeof x1);
+
+  // Dead code shouldn't warn.
+  if (false) memset(&x1, 0, sizeof x1);
+}
+
+namespace N {
+  void *memset(void *, int, unsigned);
+  void test_nowarn() {
+    N::memset(&x1, 0, sizeof x1);
+  }
+}