Author: ted Date: Thu Aug 31 12:22:33 2017 New Revision: 312270 URL: http://llvm.org/viewvc/llvm-project?rev=312270&view=rev Log: lldb-mi: -var-update can hang when traversing complex types with pointers
Summary: -var-update calls CMICmdCmdVarUpdate::ExamineSBValueForChange to check if a varObj has been updated. It checks that the varObj is updated, then recurses on all of its children. If a child is a pointer pointing back to a parent node, this will result in an infinite loop, and lldb-mi hanging. The problem is exposed by packages/Python/lldbsuite/test/tools/lldb-mi/variable/TestMiVar.py, but this test is skipped everywhere. This patch changes ExamineSBValueForChange to not traverse children of varObjs that are pointers. Reviewers: ki.stfu, zturner, clayborg, abidh Reviewed By: clayborg Subscribers: lldb-commits Differential Revision: https://reviews.llvm.org/D37154 Modified: lldb/trunk/tools/lldb-mi/MICmdCmdVar.cpp Modified: lldb/trunk/tools/lldb-mi/MICmdCmdVar.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/tools/lldb-mi/MICmdCmdVar.cpp?rev=312270&r1=312269&r2=312270&view=diff ============================================================================== --- lldb/trunk/tools/lldb-mi/MICmdCmdVar.cpp (original) +++ lldb/trunk/tools/lldb-mi/MICmdCmdVar.cpp Thu Aug 31 12:22:33 2017 @@ -509,19 +509,19 @@ bool CMICmdCmdVarUpdate::ExamineSBValueF return MIstatus::success; } - lldb::SBType valueType = vrwValue.GetType(); - const MIuint nChildren = vrwValue.GetNumChildren(); for (MIuint i = 0; i < nChildren; ++i) { lldb::SBValue member = vrwValue.GetChildAtIndex(i); if (!member.IsValid()) continue; - if (member.GetValueDidChange()) { - vrwbChanged = true; - return MIstatus::success; - } else if (ExamineSBValueForChange(member, vrwbChanged) && vrwbChanged) - // Handle composite types (i.e. struct or arrays) + // skip pointers and references to avoid infinite loop + if (member.GetType().GetTypeFlags() & + (lldb::eTypeIsPointer | lldb::eTypeIsReference)) + continue; + + // Handle composite types (i.e. struct or arrays) + if (ExamineSBValueForChange(member, vrwbChanged) && vrwbChanged) return MIstatus::success; } vrwbChanged = false; _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits