Add support for artificial tail call frames

This patch teaches lldb to detect when there are missing frames in a
backtrace due to a sequence of tail calls, and to fill in the backtrace
with artificial tail call frames when this happens. This is only done
when the execution history can be determined from the call graph and
from the return PC addresses of calls on the stack. Ambiguous sequences
of tail calls (e.g anything involving tail calls and recursion) are
detected and ignored.

Depends on D49887.

Differential Revision: https://reviews.llvm.org/D50478

llvm-svn: 343900

1 files changed, 9 insertions, 0 deletions

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
index 39c70d14652..4c91686627b 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
@@ -1060,6 +1060,15 @@ size_t SymbolFileDWARFDebugMap::GetTypes(SymbolContextScope *sc_scope,
   return type_list.GetSize() - initial_size;
 }
 
+std::vector<lldb_private::CallEdge>
+SymbolFileDWARFDebugMap::ParseCallEdgesInFunction(UserID func_id) {
+  uint32_t oso_idx = GetOSOIndexFromUserID(func_id.GetID());
+  SymbolFileDWARF *oso_dwarf = GetSymbolFileByOSOIndex(oso_idx);
+  if (oso_dwarf)
+    return oso_dwarf->ParseCallEdgesInFunction(func_id);
+  return {};
+}
+
 TypeSP SymbolFileDWARFDebugMap::FindDefinitionTypeForDWARFDeclContext(
     const DWARFDeclContext &die_decl_ctx) {
   TypeSP type_sp;