add asan_ignore - which errors to ignore

"clang -fsanitize=undefined" produces lots of false positives.
This file allows certain functions to be excluded from checking.
Use it as:

    clang -fsanitize=undefined -fsanitize-blacklist=`pwd`/asan_ignore

1 files changed, 19 insertions, 0 deletions

diff --git a/asan_ignore b/asan_ignore
new file mode 100644
index 0000000000..5a8bc5c7f9
--- /dev/null
+++ b/asan_ignore
@@ -0,0 +1,19 @@
+# This file intended to be used with clang as
+#
+#  clang -fsanitize=foo -fsanitize-blacklist=`pwd`/asan_ignore
+#
+# It lists those files / functions that clang's Address Sanitizer should
+# ignore.
+#
+# See http://clang.llvm.org/docs/SanitizerSpecialCaseList.html.
+
+
+# The pp functions used under 'use integer' shouldn't warn about
+# integer overflow etc.
+#
+# Unfortunately there doesn't seem to be any way to disable just specific
+# errors (i.e. the integer overflow ones). The manual implies that you can
+# suffix with =foo for a "tool-specific category", but neither =undefined
+# nor =signed-integer-overflow worked.
+
+fun:Perl_pp_i_*