Fix PR14568: Avoid the DFA packetizer from making an invalid read
beyond array bounds.
No test case since I cannot reproduce an ICE with this bug. According
to Carlos -- the bug reporter -- a segfault occurs only when LLVM is
compiled with a specific version of GCC.
llvm-svn: 169783
diff --git a/llvm/utils/TableGen/DFAPacketizerEmitter.cpp b/llvm/utils/TableGen/DFAPacketizerEmitter.cpp
index 0ad25a5..2549c47 100644
--- a/llvm/utils/TableGen/DFAPacketizerEmitter.cpp
+++ b/llvm/utils/TableGen/DFAPacketizerEmitter.cpp
@@ -279,6 +279,7 @@
//
//
void DFA::writeTableAndAPI(raw_ostream &OS, const std::string &TargetName) {
+ static const std::string SentinelEntry = "{-1, -1}";
DFA::StateSet::iterator SI = states.begin();
// This table provides a map to the beginning of the transitions for State s
// in DFAStateInputTable.
@@ -305,12 +306,17 @@
// If there are no valid transitions from this stage, we need a sentinel
// transition.
if (ValidTransitions == StateEntry[i]) {
- OS << "{-1, -1},";
+ OS << SentinelEntry << ",";
++ValidTransitions;
}
OS << "\n";
}
+
+ // Print out a sentinel entry at the end of the StateInputTable. This is
+ // needed to iterate over StateInputTable in DFAPacketizer::ReadTable()
+ OS << SentinelEntry << "\n";
+
OS << "};\n\n";
OS << "const unsigned int " << TargetName << "DFAStateEntryTable[] = {\n";
@@ -319,6 +325,9 @@
for (unsigned i = 0; i < states.size(); ++i)
OS << StateEntry[i] << ", ";
+ // Print out the index to the sentinel entry in StateInputTable
+ OS << ValidTransitions << ", ";
+
OS << "\n};\n";
OS << "} // namespace\n";