Author: labath Date: Wed Jun 5 00:29:55 2019 New Revision: 362586 URL: http://llvm.org/viewvc/llvm-project?rev=362586&view=rev Log: Ignore DIEs in the skeleton unit in a DWO scenario
Summary: r362103 exposed a bug, where we could read incorrect data if a skeleton unit contained more than the single unit DIE. Clang emits these kinds of units with -fsplit-dwarf-inlining (which is also the default). Changing lldb to handle these DIEs is nontrivial, as we'd have to change the UID encoding logic to be able to reference these DIEs, and fix up various places which are assuming that all DIEs come from the separate compile unit. However, it turns out this is not necessary, as the DWO unit contains all the information that the skeleton unit does. So, this patch just skips parsing the extra DIEs if we have successfully found the DWO file. This enforces the invariant that the rest of the code is already operating under. This patch fixes a couple of existing tests, but I've also included a simpler test which does not depend on execution of binaries, and would have helped us in catching this sooner. Reviewers: clayborg, JDevlieghere, aprantl Subscribers: probinson, dblaikie, lldb-commits Differential Revision: https://reviews.llvm.org/D62852 Added: lldb/trunk/lit/SymbolFile/DWARF/split-dwarf-inlining.cpp Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp Added: lldb/trunk/lit/SymbolFile/DWARF/split-dwarf-inlining.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/SymbolFile/DWARF/split-dwarf-inlining.cpp?rev=362586&view=auto ============================================================================== --- lldb/trunk/lit/SymbolFile/DWARF/split-dwarf-inlining.cpp (added) +++ lldb/trunk/lit/SymbolFile/DWARF/split-dwarf-inlining.cpp Wed Jun 5 00:29:55 2019 @@ -0,0 +1,8 @@ +// RUN: %clangxx -target x86_64-pc-linux -gsplit-dwarf -fsplit-dwarf-inlining \ +// RUN: -c %s -o %t +// RUN: %lldb %t -o "breakpoint set -n foo" -b | FileCheck %s + +// CHECK: Breakpoint 1: 2 locations + +__attribute__((always_inline)) int foo(int x) { return x; } +int bar(int x) { return foo(x); } Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp?rev=362586&r1=362585&r2=362586&view=diff ============================================================================== --- lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp (original) +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp Wed Jun 5 00:29:55 2019 @@ -183,6 +183,17 @@ void DWARFUnit::ExtractDIEsRWLocked() { if (!m_first_die) AddUnitDIE(m_die_array.front()); + + // With -fsplit-dwarf-inlining, clang will emit non-empty skeleton compile + // units. We are not able to access these DIE *and* the dwo file + // simultaneously. We also don't need to do that as the dwo file will + // contain a superset of information. So, we don't even attempt to parse + // any remaining DIEs. + if (m_dwo_symbol_file) { + m_die_array.front().SetHasChildren(false); + break; + } + } else { if (null_die) { if (prev_die_had_children) { _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
