DWARF: Generate the address lookup table from the DIE tree if .debug_aranges is not available.

Ported from LLDB.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139732 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/DebugInfo/DWARFDebugAranges.h b/lib/DebugInfo/DWARFDebugAranges.h
index 8fe70e4..12afb60 100644
--- a/lib/DebugInfo/DWARFDebugAranges.h
+++ b/lib/DebugInfo/DWARFDebugAranges.h
@@ -64,6 +64,7 @@
   bool allRangesAreContiguous(uint64_t& LoPC, uint64_t& HiPC) const;
   bool getMaxRange(uint64_t& LoPC, uint64_t& HiPC) const;
   bool extract(DataExtractor debug_aranges_data);
+  bool generate(DWARFContext *ctx);
 
   // Use append range multiple times and then call sort
   void appendRange(uint32_t cu_offset, uint64_t low_pc, uint64_t high_pc);