DebugNamesDWARFIndex: Add support for partial indexes

Summary:
It possible that a single module has indexed and non-indexed compile
units. In this case, we can use the fast indexed lookup for the first
ones and fall back to the manual index for the others.

This patch implements this functionality by adding a units_to_avoid
argument to the ManualDWARFIndex constructor. Any units present in that
list will be ignored for the purposes of manual index. Individual
DebugNamesDWARFIndex then always consult both the manual fallback index
as well as the index in the .debug_names section.

Reviewers: JDevlieghere, clayborg

Subscribers: aprantl, lldb-commits

Differential Revision: https://reviews.llvm.org/D47832

llvm-svn: 334185

1 files changed, 7 insertions, 2 deletions

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.h b/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.h
index 9ce446a5af6..79ab1d95b38 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.h
@@ -12,12 +12,15 @@
 
 #include "Plugins/SymbolFile/DWARF/DWARFIndex.h"
 #include "Plugins/SymbolFile/DWARF/NameToDIE.h"
+#include "llvm/ADT/DenseSet.h"
 
 namespace lldb_private {
 class ManualDWARFIndex : public DWARFIndex {
 public:
-  ManualDWARFIndex(Module &module, DWARFDebugInfo *debug_info)
-      : DWARFIndex(module), m_debug_info(debug_info) {}
+  ManualDWARFIndex(Module &module, DWARFDebugInfo *debug_info,
+                   llvm::DenseSet<dw_offset_t> units_to_avoid = {})
+      : DWARFIndex(module), m_debug_info(debug_info),
+        m_units_to_avoid(std::move(units_to_avoid)) {}
 
   void Preload() override { Index(); }
 
@@ -62,6 +65,8 @@ private:
 
   /// Non-null value means we haven't built the index yet.
   DWARFDebugInfo *m_debug_info;
+  /// Which dwarf units should we skip while building the index.
+  llvm::DenseSet<dw_offset_t> m_units_to_avoid;
 
   IndexSet m_set;
 };