[llvm-commits] [llvm] r169783 - /llvm/trunk/utils/TableGen/DFAPacketizerEmitter.cpp
Anshuman Dasgupta
adasgupt at codeaurora.org
Mon Dec 10 14:45:57 PST 2012
Author: adasgupt
Date: Mon Dec 10 16:45:57 2012
New Revision: 169783
URL: http://llvm.org/viewvc/llvm-project?rev=169783&view=rev
Log:
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.
Modified:
llvm/trunk/utils/TableGen/DFAPacketizerEmitter.cpp
Modified: llvm/trunk/utils/TableGen/DFAPacketizerEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/DFAPacketizerEmitter.cpp?rev=169783&r1=169782&r2=169783&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/DFAPacketizerEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/DFAPacketizerEmitter.cpp Mon Dec 10 16:45:57 2012
@@ -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";
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