From e7a0719161ebc3600d3f584901ab8e2276acdb59 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Mon, 17 Oct 2011 20:49:40 +0000 Subject: 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 --- lib/Support/StringRef.cpp | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'lib/Support/StringRef.cpp') diff --git a/lib/Support/StringRef.cpp b/lib/Support/StringRef.cpp index a862ed2fa9..576b95f6a4 100644 --- a/lib/Support/StringRef.cpp +++ b/lib/Support/StringRef.cpp @@ -153,19 +153,22 @@ size_t StringRef::find(StringRef Str, size_t From) const { 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; } -- cgit v1.2.3-18-g5258