Merge pull request swiftlang#7590 from apple/jdevlieghere/rdar/111525100

[DWARFLinker] Release input DWARF after object has been linked

Author: JDevlieghere

llvm/include/llvm/DWARFLinker/DWARFLinker.h

@@ -13,13 +13,13 @@
 #include "llvm/CodeGen/AccelTable.h"
 #include "llvm/CodeGen/NonRelocatableStringpool.h"
 #include "llvm/DWARFLinker/DWARFLinkerCompileUnit.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include <map>
 
 namespace llvm {
-class DWARFContext;
 class DWARFExpression;
 class DWARFUnit;
 class DataExtractor;
@@ -196,19 +196,26 @@ using UnitListTy = std::vector<std::unique_ptr<CompileUnit>>;
 /// and it`s address map.
 class DWARFFile {
 public:
-  DWARFFile(StringRef Name, DWARFContext *Dwarf, AddressesMap *Addresses,
+  DWARFFile(StringRef Name, std::unique_ptr<DWARFContext> Dwarf,
+            std::unique_ptr<AddressesMap> Addresses,
             const std::vector<std::string> &Warnings)
-      : FileName(Name), Dwarf(Dwarf), Addresses(Addresses), Warnings(Warnings) {
-  }
+      : FileName(Name), Dwarf(std::move(Dwarf)),
+        Addresses(std::move(Addresses)), Warnings(Warnings) {}
 
   /// object file name.
   StringRef FileName;
-  /// source DWARF information.
-  DWARFContext *Dwarf = nullptr;
-  /// helpful address information(list of valid address ranges, relocations).
-  AddressesMap *Addresses = nullptr;
+  /// The source DWARF information.
+  std::unique_ptr<DWARFContext> Dwarf;
+  /// Helpful address information(list of valid address ranges, relocations).
+  std::unique_ptr<AddressesMap> Addresses;
   /// warnings for object file.
   const std::vector<std::string> &Warnings;
+
+  /// Unloads object file and corresponding AddressesMap and Dwarf Context.
+  void unload() {
+    Addresses.reset();
+    Dwarf.reset();
+  }
 };
 
 typedef std::function<void(const Twine &Warning, StringRef Context,
@@ -445,7 +452,8 @@ class DWARFLinker {
     /// the debug object.
     void clear() {
       CompileUnits.clear();
-      File.Addresses->clear();
+      ModuleUnits.clear();
+      File.unload();
     }
   };
 

llvm/tools/dsymutil/DwarfLinkerForBinary.cpp

@@ -272,14 +272,9 @@ DwarfLinkerForBinary::loadObject(const DebugMapObject &Obj,
   auto ErrorOrObj = loadObject(Obj, DebugMap.getTriple());
 
   if (ErrorOrObj) {
-    ContextForLinking.push_back(
-        std::unique_ptr<DWARFContext>(DWARFContext::create(*ErrorOrObj)));
-    AddressMapForLinking.push_back(
-        std::make_unique<AddressManager>(*this, *ErrorOrObj, Obj));
-
     ObjectsForLinking.push_back(std::make_unique<DWARFFile>(
-        Obj.getObjectFilename(), ContextForLinking.back().get(),
-        AddressMapForLinking.back().get(),
+        Obj.getObjectFilename(), DWARFContext::create(*ErrorOrObj),
+        std::make_unique<AddressManager>(*this, *ErrorOrObj, Obj),
         Obj.empty() ? Obj.getWarnings() : EmptyWarnings));
 
     Error E = RL.link(*ErrorOrObj);
@@ -554,8 +549,6 @@ bool DwarfLinkerForBinary::link(const DebugMap &Map) {
     return false;
 
   ObjectsForLinking.clear();
-  ContextForLinking.clear();
-  AddressMapForLinking.clear();
 
   DebugMap DebugMap(Map.getTriple(), Map.getBinaryPath());
 

llvm/tools/dsymutil/DwarfLinkerForBinary.h

@@ -221,8 +221,6 @@ class DwarfLinkerForBinary {
   LinkOptions Options;
   std::unique_ptr<DwarfStreamer> Streamer;
   std::vector<std::unique_ptr<DWARFFile>> ObjectsForLinking;
-  std::vector<std::unique_ptr<DWARFContext>> ContextForLinking;
-  std::vector<std::unique_ptr<AddressManager>> AddressMapForLinking;
   std::vector<std::string> EmptyWarnings;
 
   /// A list of all .swiftinterface files referenced by the debug

llvm/tools/llvm-dwarfutil/DebugInfoLinker.cpp

@@ -305,7 +305,6 @@ Error linkDebugInfo(object::ObjectFile &File, const Options &Options,
   DebugInfoLinker.setUpdate(!Options.DoGarbageCollection);
 
   std::vector<std::unique_ptr<DWARFFile>> ObjectsForLinking(1);
-  std::vector<std::unique_ptr<AddressesMap>> AddresssMapForLinking(1);
   std::vector<std::string> EmptyWarnings;
 
   // Unknown debug sections would be removed. Display warning
@@ -319,11 +318,9 @@ Error linkDebugInfo(object::ObjectFile &File, const Options &Options,
   }
 
   // Add object files to the DWARFLinker.
-  AddresssMapForLinking[0] =
-      std::make_unique<ObjFileAddressMap>(*Context, Options, File);
-
   ObjectsForLinking[0] = std::make_unique<DWARFFile>(
-      File.getFileName(), &*Context, AddresssMapForLinking[0].get(),
+      File.getFileName(), DWARFContext::create(File),
+      std::make_unique<ObjFileAddressMap>(*Context, Options, File),
       EmptyWarnings);
 
   for (size_t I = 0; I < ObjectsForLinking.size(); I++)