Warn on memset(ptr, 0, sizeof(ptr)). Diagnostic wording by Jordy Rose.

llvm-svn: 132996

1 files changed, 97 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/warn-memset-bad-sizeof.cpp b/clang/test/SemaCXX/warn-memset-bad-sizeof.cpp
new file mode 100644
index 00000000000..c000b447738
--- /dev/null
+++ b/clang/test/SemaCXX/warn-memset-bad-sizeof.cpp
@@ -0,0 +1,97 @@
+// RUN: %clang_cc1 -fsyntax-only -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);
+
+struct S {int a, b, c, d;};
+typedef S* PS;
+
+struct Foo {};
+typedef const Foo& CFooRef;
+typedef const Foo CFoo;
+typedef volatile Foo VFoo;
+typedef const volatile Foo CVFoo;
+
+typedef double Mat[4][4];
+
+template <class Dest, class Source>
+inline Dest bit_cast(const Source& source) {
+  Dest dest;
+  memcpy(&dest, &source, sizeof(dest));
+  return dest;
+}
+
+// http://www.lysator.liu.se/c/c-faq/c-2.html#2-6
+void f(char fake_array[8], Mat m, const Foo& const_foo) {
+  S s;
+  S* ps = &s;
+  PS ps2 = &s;
+  char arr[5];
+  char* parr[5];
+  Foo foo;
+
+  /* Should warn */
+  memset(&s, 0, sizeof(&s));  // \
+      // expected-warning {{the argument to sizeof is pointer type 'S *', expected 'S' to match first argument to 'memset'}}
+  memset(ps, 0, sizeof(ps));  // \
+      // expected-warning {{the argument to sizeof is pointer type 'S *', expected 'S' to match first argument to 'memset'}}
+  memset(ps2, 0, sizeof(ps2));  // \
+      // expected-warning {{the argument to sizeof is pointer type 'PS' (aka 'S *'), expected 'S' to match first argument to 'memset'}}
+  memset(ps2, 0, sizeof(typeof(ps2)));  // \
+      // expected-warning {{the argument to sizeof is pointer type 'typeof (ps2)' (aka 'S *'), expected 'S' to match first argument to 'memset'}}
+  memset(ps2, 0, sizeof(PS));  // \
+      // expected-warning {{the argument to sizeof is pointer type 'PS' (aka 'S *'), expected 'S' to match first argument to 'memset'}}
+  memset(fake_array, 0, sizeof(fake_array));  // \
+      // expected-warning {{the argument to sizeof is pointer type 'char *', expected 'char' to match first argument to 'memset'}}
+
+  memcpy(&s, 0, sizeof(&s));  // \
+      // expected-warning {{the argument to sizeof is pointer type 'S *', expected 'S' to match first argument to 'memcpy'}}
+  memcpy(0, &s, sizeof(&s));  // \
+      // expected-warning {{the argument to sizeof is pointer type 'S *', expected 'S' to match second argument to 'memcpy'}}
+
+  /* Shouldn't warn */
+  memset((void*)&s, 0, sizeof(&s));
+  memset(&s, 0, sizeof(s));
+  memset(&s, 0, sizeof(S));
+  memset(&s, 0, sizeof(const S));
+  memset(&s, 0, sizeof(volatile S));
+  memset(&s, 0, sizeof(volatile const S));
+  memset(&foo, 0, sizeof(CFoo));
+  memset(&foo, 0, sizeof(VFoo));
+  memset(&foo, 0, sizeof(CVFoo));
+  memset(ps, 0, sizeof(*ps));
+  memset(ps2, 0, sizeof(*ps2));
+  memset(ps2, 0, sizeof(typeof(*ps2)));
+  memset(arr, 0, sizeof(arr));
+  memset(parr, 0, sizeof(parr));
+
+  memcpy(&foo, &const_foo, sizeof(Foo));
+  memcpy((void*)&s, 0, sizeof(&s));
+  memcpy(0, (void*)&s, sizeof(&s));
+
+  CFooRef cfoo = foo;
+  memcpy(&foo, &cfoo, sizeof(Foo));
+
+  memcpy(0, &arr, sizeof(arr));
+  typedef char Buff[8];
+  memcpy(0, &arr, sizeof(Buff));
+
+  unsigned char* puc;
+  bit_cast<char*>(puc);
+
+  float* pf;
+  bit_cast<int*>(pf);
+
+  int iarr[14];
+  memset(&iarr[0], 0, sizeof iarr);
+
+  int* iparr[14];
+  memset(&iparr[0], 0, sizeof iparr);
+
+  memset(m, 0, sizeof(Mat));
+
+  // Copy to raw buffer shouldn't warn either
+  memcpy(&foo, &arr, sizeof(Foo));
+  memcpy(&arr, &foo, sizeof(Foo));
+}