Fix handling of the From parameter in StringRef::find.
Enable bounds checking to catch this kind of bug earlier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142247 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/StringRef.cpp b/lib/Support/StringRef.cpp
index a862ed2..576b95f 100644
--- a/lib/Support/StringRef.cpp
+++ b/lib/Support/StringRef.cpp
@@ -153,19 +153,22 @@
return npos;
}
+ if (From >= Length)
+ return npos;
+
// Build the bad char heuristic table, with uint8_t to reduce cache thrashing.
uint8_t BadCharSkip[256];
std::memset(BadCharSkip, N, 256);
for (unsigned i = 0; i != N-1; ++i)
BadCharSkip[(uint8_t)Str[i]] = N-1-i;
- unsigned Len = Length, Pos = min(From, Length);
+ unsigned Len = Length-From, Pos = From;
while (Len >= N) {
if (substr(Pos, N).equals(Str)) // See if this is the correct substring.
return Pos;
// Otherwise skip the appropriate number of bytes.
- uint8_t Skip = BadCharSkip[(uint8_t)Data[Pos+N-1]];
+ uint8_t Skip = BadCharSkip[(uint8_t)(*this)[Pos+N-1]];
Len -= Skip;
Pos += Skip;
}
