[PATCH] D90006: Exposes interface to free up caching data structure in DWARFDebugLine and DWARFUnit for memory management

[Hyoun Kyu Cho via Phabricator via llvm-commits]

netforce created this revision.
netforce added reviewers: labath, dblaikie.
netforce added a project: debug-info.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.
netforce requested review of this revision.

This is minimum changes extracted from https://reviews.llvm.org/D78950. The old patch tried to add LRU eviction of caching data structure. Due to multiple layers of interfaces that users could be using, it was not clear where to put the functionality. While we work out on where to put that functionality, it'll be great to add this minimum interface change so that the user could implement their own memory management. More specifically


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D90006

Files:
  llvm/include/llvm/DebugInfo/DWARF/DWARFContext.h
  llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLine.h
  llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
  llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
  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
@@ -342,6 +342,9 @@
   LocSectionBase = 0;
   AddrOffsetSectionBase = None;
   clearDIEs(false);
+  AddrDieMap.clear();
+  if (DWO)
+    DWO->clear();
   DWO.reset();
 }
 
Index: llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
===================================================================
--- llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -597,6 +597,10 @@
   return LT;
 }
 
+void DWARFDebugLine::clearLineTable(uint64_t Offset) {
+  LineTableMap.erase(Offset);
+}
+
 static StringRef getOpcodeName(uint8_t Opcode, uint8_t OpcodeBase) {
   assert(Opcode != 0);
   if (Opcode < OpcodeBase)
Index: llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
===================================================================
--- llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -960,6 +960,22 @@
                                    RecoverableErrorHandler);
 }
 
+void DWARFContext::clearLineTableForUnit(DWARFUnit *U) {
+  if (!Line)
+    return;
+
+  auto UnitDIE = U->getUnitDIE();
+  if (!UnitDIE)
+    return;
+
+  auto Offset = toSectionOffset(UnitDIE.find(DW_AT_stmt_list));
+  if (!Offset)
+    return;
+
+  uint64_t stmtOffset = *Offset + U->getLineTableOffset();
+  Line->clearLineTable(stmtOffset);
+}
+
 void DWARFContext::parseNormalUnits() {
   if (!NormalUnits.empty())
     return;
Index: llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLine.h
===================================================================
--- llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLine.h
+++ llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLine.h
@@ -311,6 +311,7 @@
   getOrParseLineTable(DWARFDataExtractor &DebugLineData, uint64_t Offset,
                       const DWARFContext &Ctx, const DWARFUnit *U,
                       function_ref<void(Error)> RecoverableErrorHandler);
+  void clearLineTable(uint64_t Offset);
 
   /// Helper to allow for parsing of an entire .debug_line section in sequence.
   class SectionParser {
Index: llvm/include/llvm/DebugInfo/DWARF/DWARFContext.h
===================================================================
--- llvm/include/llvm/DebugInfo/DWARF/DWARFContext.h
+++ llvm/include/llvm/DebugInfo/DWARF/DWARFContext.h
@@ -326,6 +326,10 @@
   getLineTableForUnit(DWARFUnit *U,
                       function_ref<void(Error)> RecoverableErrorHandler);
 
+  // Clear the line table object corresponding to a compile unit for memory
+  // management purpose. When it's referred to again, it'll be re-populated.
+  void clearLineTableForUnit(DWARFUnit *U);
+
   DataExtractor getStringExtractor() const {
     return DataExtractor(DObj->getStrSection(), false, 0);
   }


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