[PATCH] D109499: [DebugInfo][NFC] Erase capacity in DWARFUnit::clearDIEs().

[Alexey Lapshin via Phabricator via llvm-commits]

avl updated this revision to Diff 371690.
avl added a comment.

addressed comments.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109499/new/

https://reviews.llvm.org/D109499

Files:
  llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp


Index: llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
===================================================================
--- llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -577,10 +577,14 @@
 }
 
 void DWARFUnit::clearDIEs(bool KeepCUDie) {
-  if (DieArray.size() > (unsigned)KeepCUDie) {
-    DieArray.resize((unsigned)KeepCUDie);
-    DieArray.shrink_to_fit();
-  }
+  // Do not use resize() + shrink_to_fit() to free memory occupied by dies.
+  // shrink_to_fit() is a *non-binding* request to reduce capacity() to size().
+  // It depends on the implementation whether the request is fulfilled.
+  // Create a new vector with a small capacity and assign it to the DieArray to
+  // have previous contents freed.
+  DieArray = (KeepCUDie && !DieArray.empty())
+                 ? std::vector<DWARFDebugInfoEntry>({DieArray[0]})
+                 : std::vector<DWARFDebugInfoEntry>();
 }
 
 Expected<DWARFAddressRangesVector>


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