Make detect_invalid_pointer_pairs option to be tristate.

Summary:
With the change, one can choose not to report comparison (or subtraction)
of a pointer with nullptr pointer.

Reviewers: kcc, jakubjelinek, alekseyshl

Reviewed By: alekseyshl

Subscribers: kubamracek

Differential Revision: https://reviews.llvm.org/D41479

llvm-svn: 323995

1 files changed, 42 insertions, 0 deletions

diff --git a/compiler-rt/test/asan/TestCases/invalid-pointer-pairs-compare-null.cc b/compiler-rt/test/asan/TestCases/invalid-pointer-pairs-compare-null.cc
new file mode 100644
index 00000000000..dfc56616a4d
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/invalid-pointer-pairs-compare-null.cc
@@ -0,0 +1,42 @@
+// RUN: %clangxx_asan -O0 %s -o %t -mllvm -asan-detect-invalid-pointer-pair
+
+// RUN: %env_asan_opts=detect_invalid_pointer_pairs=1 %run %t
+
+#include <assert.h>
+#include <stdlib.h>
+
+int foo(char *p, char *q) {
+  return p <= q;
+}
+
+char global[8192] = {};
+char small_global[7] = {};
+
+int main() {
+  // Heap allocated memory.
+  char *p = (char *)malloc(42);
+  int r = foo(p, nullptr);
+  free(p);
+
+  p = (char *)malloc(1024);
+  foo(nullptr, p);
+  free(p);
+
+  p = (char *)malloc(4096);
+  foo(p, nullptr);
+  free(p);
+
+  // Global variable.
+  foo(&global[0], nullptr);
+  foo(&global[1000], nullptr);
+
+  p = &small_global[0];
+  foo(p, nullptr);
+
+  // Stack variable.
+  char stack[10000];
+  foo(&stack[0], nullptr);
+  foo(nullptr, &stack[9000]);
+
+  return 0;
+}