Expand array bounds checking to work in the presence of unary & and *,

and to work with pointer arithmetic in addition to array indexing.

The new pointer arithmetic porition of the array bounds checking can be
turned on by -Warray-bounds-pointer-arithmetic (and is off by default).

llvm-svn: 136046

1 files changed, 33 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/array-bounds-ptr-arith.cpp b/clang/test/SemaCXX/array-bounds-ptr-arith.cpp
new file mode 100644
index 00000000000..ce1ace6f2fb
--- /dev/null
+++ b/clang/test/SemaCXX/array-bounds-ptr-arith.cpp
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 -verify -Warray-bounds-pointer-arithmetic %s
+
+void swallow (const char *x) { (void)x; }
+void test_pointer_arithmetic(int n) {
+  const char hello[] = "Hello world!"; // expected-note 2 {{declared here}}
+  const char *helloptr = hello;
+
+  swallow("Hello world!" + 6); // no-warning
+  swallow("Hello world!" - 6); // expected-warning {{refers before the beginning of the array}}
+  swallow("Hello world!" + 14); // expected-warning {{refers past the end of the array}}
+  swallow("Hello world!" + 13); // no-warning
+
+  swallow(hello + 6); // no-warning
+  swallow(hello - 6); // expected-warning {{refers before the beginning of the array}}
+  swallow(hello + 14); // expected-warning {{refers past the end of the array}}
+  swallow(hello + 13); // no-warning
+
+  swallow(helloptr + 6); // no-warning
+  swallow(helloptr - 6); // no-warning
+  swallow(helloptr + 14); // no-warning
+  swallow(helloptr + 13); // no-warning
+
+  double numbers[2]; // expected-note {{declared here}}
+  swallow((char*)numbers + sizeof(double)); // no-warning
+  swallow((char*)numbers + 60); // expected-warning {{refers past the end of the array}}
+
+  char buffer[5]; // expected-note 2 {{declared here}}
+  // TODO: Add FixIt notes for adding parens around non-ptr part of arith expr
+  swallow(buffer + sizeof("Hello")-1); // expected-warning {{refers past the end of the array}}
+  swallow(buffer + (sizeof("Hello")-1)); // no-warning
+  if (n > 0 && n <= 6) swallow(buffer + 6 - n); // expected-warning {{refers past the end of the array}}
+  if (n > 0 && n <= 6) swallow(buffer + (6 - n)); // no-warning
+}