Allow-list unsigned integer overflows.
This CL adds the 'no_sanitize("unsigned-integer-overflow")' Clang/LLVM
attribute to several locations that intentionally rely on that behavior.
From https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html: "this
is not undefined behavior, but it is often unintentional." By using an
explicit allow-list, we should still be able to detect the latter case.
Change-Id: I7d7da40c73fd22b6b29196dc4788eb00fca61439
Bug: 190
diff --git a/pw_tokenizer/simple_tokenize_test.cc b/pw_tokenizer/simple_tokenize_test.cc
index ce84db8..7af8702 100644
--- a/pw_tokenizer/simple_tokenize_test.cc
+++ b/pw_tokenizer/simple_tokenize_test.cc
@@ -23,7 +23,8 @@
namespace {
template <size_t kSize>
-uint32_t TestHash(const char (&str)[kSize]) {
+uint32_t TestHash(const char (&str)[kSize])
+ PW_NO_SANITIZE("unsigned-integer-overflow") {
static_assert(kSize > 0u, "Must have at least a null terminator");
static constexpr uint32_t k65599HashConstant = 65599u;
@@ -36,6 +37,8 @@
std::min(static_cast<size_t>(PW_TOKENIZER_CFG_HASH_LENGTH), kSize - 1);
// Hash all of the characters in the string as unsigned ints.
+ // The coefficient calculation is done modulo 0x100000000, so the unsigned
+ // integer overflows are intentional.
for (size_t i = 0; i < length; ++i) {
hash += coefficient * str[i];
coefficient *= k65599HashConstant;