[libFuzzer] Fix endianness issue in ForEachNonZeroByte()
The usage pattern of Bundle variable assumes the machine is little
endian, which is not the case on SystemZ. Fix by converting Bundle to
little-endian when necessary.
GitOrigin-RevId: a4e537d9c47aa378a24636e2d90d208389ad93ab
diff --git a/FuzzerTracePC.h b/FuzzerTracePC.h
index 501f3b5..4601300 100644
--- a/FuzzerTracePC.h
+++ b/FuzzerTracePC.h
@@ -194,10 +194,12 @@
// Iterate by Step bytes at a time.
for (; P < End; P += Step)
- if (LargeType Bundle = *reinterpret_cast<const LargeType *>(P))
+ if (LargeType Bundle = *reinterpret_cast<const LargeType *>(P)) {
+ Bundle = HostToLE(Bundle);
for (size_t I = 0; I < Step; I++, Bundle >>= 8)
if (uint8_t V = Bundle & 0xff)
Handle8bitCounter(FirstFeature, P - Begin + I, V);
+ }
// Iterate by 1 byte until the end.
for (; P < End; P++)
diff --git a/FuzzerUtil.h b/FuzzerUtil.h
index 4ae3583..e90be08 100644
--- a/FuzzerUtil.h
+++ b/FuzzerUtil.h
@@ -106,6 +106,12 @@
return reinterpret_cast<uint8_t *>(X);
}
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+template <typename T> T HostToLE(T X) { return X; }
+#else
+template <typename T> T HostToLE(T X) { return Bswap(X); }
+#endif
+
} // namespace fuzzer
#endif // LLVM_FUZZER_UTIL_H
