[llvm] 821954f - DebugInfo: Add a FIXME/suggestion about using sibling/parent index to DWARFDebugInfoEntry

[David Blaikie via llvm-commits]

Author: David Blaikie
Date: 2021-09-06T10:20:39-07:00
New Revision: 821954f97c6b978cca72cb412e98d35caee4cac3

URL: https://github.com/llvm/llvm-project/commit/821954f97c6b978cca72cb412e98d35caee4cac3
DIFF: https://github.com/llvm/llvm-project/commit/821954f97c6b978cca72cb412e98d35caee4cac3.diff

LOG: DebugInfo: Add a FIXME/suggestion about using sibling/parent index to DWARFDebugInfoEntry

As a reminder if someone comes looking to improve iteration or parent
navigation performance of DWARFDebugInfoEntry.

Added: 
    

Modified: 
    llvm/include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h

Removed: 
    


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diff  --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h
index 2ba320417b51f..c198d37922812 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h
@@ -24,6 +24,11 @@ class DWARFDebugInfoEntry {
   /// Offset within the .debug_info of the start of this entry.
   uint64_t Offset = 0;
 
+  // FIXME: This could be changed to a parent_idx/sibling_idx based solution
+  // like lldb's that could be used to improve the performance of sibling
+  // iteration. Memory usage is probably acceptable - if it's good enough for
+  // lldb it's probably good enough for llvm-symbolizer, etc.
+  // There's some discussion of this direction in D102634.
   /// The integer depth of this DIE within the compile unit DIEs where the
   /// compile/type unit DIE has a depth of zero.
   uint32_t Depth = 0;