Use IntrusiveRefCntPtr to manage the lifetime of BitCodeAbbrevs.

This doesn't change the interface or gives additional safety but removes
a ton of retain/release boilerplate.

No functionality change.

llvm-svn: 217778

include/llvm/Bitcode/BitCodes.h

@@ -18,6 +18,7 @@
 #ifndef LLVM_BITCODE_BITCODES_H
 #define LLVM_BITCODE_BITCODES_H
 
+#include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -161,16 +162,12 @@ template <> struct isPodLike<BitCodeAbbrevOp> { static const bool value=true; };
 /// BitCodeAbbrev - This class represents an abbreviation record.  An
 /// abbreviation allows a complex record that has redundancy to be stored in a
 /// specialized format instead of the fully-general, fully-vbr, format.
-class BitCodeAbbrev {
+class BitCodeAbbrev : public RefCountedBase<BitCodeAbbrev> {
   SmallVector<BitCodeAbbrevOp, 32> OperandList;
-  unsigned char RefCount; // Number of things using this.
   ~BitCodeAbbrev() {}
+  friend class RefCountedBase; // Only RefCountedBase is allowed to delete.
+
 public:
-  BitCodeAbbrev() : RefCount(1) {}
-
-  void addRef() { ++RefCount; }
-  void dropRef() { if (--RefCount == 0) delete this; }
-
   unsigned getNumOperandInfos() const {
     return static_cast<unsigned>(OperandList.size());
   }

include/llvm/Bitcode/BitstreamReader.h

@@ -37,7 +37,7 @@ public:
   /// These describe abbreviations that all blocks of the specified ID inherit.
   struct BlockInfo {
     unsigned BlockID;
-    std::vector<BitCodeAbbrev*> Abbrevs;
+    std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> Abbrevs;
     std::string Name;
 
     std::vector<std::pair<unsigned, std::string> > RecordNames;
@@ -86,18 +86,6 @@ public:
 
   StreamableMemoryObject &getBitcodeBytes() { return *BitcodeBytes; }
 
-  ~BitstreamReader() {
-    // Free the BlockInfoRecords.
-    while (!BlockInfoRecords.empty()) {
-      BlockInfo &Info = BlockInfoRecords.back();
-      // Free blockinfo abbrev info.
-      for (unsigned i = 0, e = static_cast<unsigned>(Info.Abbrevs.size());
-           i != e; ++i)
-        Info.Abbrevs[i]->dropRef();
-      BlockInfoRecords.pop_back();
-    }
-  }
-
   /// CollectBlockInfoNames - This is called by clients that want block/record
   /// name information.
   void CollectBlockInfoNames() { IgnoreBlockInfoNames = false; }
@@ -208,11 +196,11 @@ class BitstreamCursor {
   unsigned CurCodeSize;
 
   /// CurAbbrevs - Abbrevs installed at in this block.
-  std::vector<BitCodeAbbrev*> CurAbbrevs;
+  std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> CurAbbrevs;
 
   struct Block {
     unsigned PrevCodeSize;
-    std::vector<BitCodeAbbrev*> PrevAbbrevs;
+    std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> PrevAbbrevs;
     explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
   };
 
@@ -222,10 +210,6 @@ class BitstreamCursor {
 
 public:
   BitstreamCursor() : BitStream(nullptr), NextChar(0) {}
-  BitstreamCursor(const BitstreamCursor &RHS)
-      : BitStream(nullptr), NextChar(0) {
-    operator=(RHS);
-  }
 
   explicit BitstreamCursor(BitstreamReader &R) : BitStream(&R) {
     NextChar = 0;
@@ -244,12 +228,6 @@ public:
     CurCodeSize = 2;
   }
 
-  ~BitstreamCursor() {
-    freeState();
-  }
-
-  void operator=(const BitstreamCursor &RHS);
-
   void freeState();
 
   bool isEndPos(size_t pos) {
@@ -529,12 +507,7 @@ private:
   void popBlockScope() {
     CurCodeSize = BlockScope.back().PrevCodeSize;
 
-    // Delete abbrevs from popped scope.
-    for (unsigned i = 0, e = static_cast<unsigned>(CurAbbrevs.size());
-         i != e; ++i)
-      CurAbbrevs[i]->dropRef();
-
-    BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
+    CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
     BlockScope.pop_back();
   }
 
@@ -555,7 +528,7 @@ public:
   const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
     unsigned AbbrevNo = AbbrevID-bitc::FIRST_APPLICATION_ABBREV;
     assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!");
-    return CurAbbrevs[AbbrevNo];
+    return CurAbbrevs[AbbrevNo].get();
   }
 
   /// skipRecord - Read the current record and discard it.

include/llvm/Bitcode/BitstreamWriter.h

@@ -40,12 +40,12 @@ class BitstreamWriter {
   unsigned BlockInfoCurBID;
 
   /// CurAbbrevs - Abbrevs installed at in this block.
-  std::vector<BitCodeAbbrev*> CurAbbrevs;
+  std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> CurAbbrevs;
 
   struct Block {
     unsigned PrevCodeSize;
     unsigned StartSizeWord;
-    std::vector<BitCodeAbbrev*> PrevAbbrevs;
+    std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> PrevAbbrevs;
     Block(unsigned PCS, unsigned SSW) : PrevCodeSize(PCS), StartSizeWord(SSW) {}
   };
 
@@ -56,7 +56,7 @@ class BitstreamWriter {
   /// These describe abbreviations that all blocks of the specified ID inherit.
   struct BlockInfo {
     unsigned BlockID;
-    std::vector<BitCodeAbbrev*> Abbrevs;
+    std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> Abbrevs;
   };
   std::vector<BlockInfo> BlockInfoRecords;
 
@@ -99,16 +99,6 @@ public:
   ~BitstreamWriter() {
     assert(CurBit == 0 && "Unflushed data remaining");
     assert(BlockScope.empty() && CurAbbrevs.empty() && "Block imbalance");
-
-    // Free the BlockInfoRecords.
-    while (!BlockInfoRecords.empty()) {
-      BlockInfo &Info = BlockInfoRecords.back();
-      // Free blockinfo abbrev info.
-      for (unsigned i = 0, e = static_cast<unsigned>(Info.Abbrevs.size());
-           i != e; ++i)
-        Info.Abbrevs[i]->dropRef();
-      BlockInfoRecords.pop_back();
-    }
   }
 
   /// \brief Retrieve the current position in the stream, in bits.
@@ -231,22 +221,13 @@ public:
     // If there is a blockinfo for this BlockID, add all the predefined abbrevs
     // to the abbrev list.
     if (BlockInfo *Info = getBlockInfo(BlockID)) {
-      for (unsigned i = 0, e = static_cast<unsigned>(Info->Abbrevs.size());
-           i != e; ++i) {
-        CurAbbrevs.push_back(Info->Abbrevs[i]);
-        Info->Abbrevs[i]->addRef();
-      }
+      CurAbbrevs.insert(CurAbbrevs.end(), Info->Abbrevs.begin(),
+                        Info->Abbrevs.end());
     }
   }
 
   void ExitBlock() {
     assert(!BlockScope.empty() && "Block scope imbalance!");
-
-    // Delete all abbrevs.
-    for (unsigned i = 0, e = static_cast<unsigned>(CurAbbrevs.size());
-         i != e; ++i)
-      CurAbbrevs[i]->dropRef();
-
     const Block &B = BlockScope.back();
 
     // Block tail:
@@ -263,7 +244,7 @@ public:
 
     // Restore the inner block's code size and abbrev table.
     CurCodeSize = B.PrevCodeSize;
-    BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
+    CurAbbrevs = std::move(B.PrevAbbrevs);
     BlockScope.pop_back();
   }
 
@@ -317,7 +298,7 @@ private:
     unsigned BlobLen = (unsigned) Blob.size();
     unsigned AbbrevNo = Abbrev-bitc::FIRST_APPLICATION_ABBREV;
     assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!");
-    BitCodeAbbrev *Abbv = CurAbbrevs[AbbrevNo];
+    const BitCodeAbbrev *Abbv = CurAbbrevs[AbbrevNo].get();
 
     EmitCode(Abbrev);
 

lib/Bitcode/Reader/BitstreamReader.cpp

@@ -15,41 +15,11 @@ using namespace llvm;
 //  BitstreamCursor implementation
 //===----------------------------------------------------------------------===//
 
-void BitstreamCursor::operator=(const BitstreamCursor &RHS) {
-  freeState();
-
-  BitStream = RHS.BitStream;
-  NextChar = RHS.NextChar;
-  CurWord = RHS.CurWord;
-  BitsInCurWord = RHS.BitsInCurWord;
-  CurCodeSize = RHS.CurCodeSize;
-
-  // Copy abbreviations, and bump ref counts.
-  CurAbbrevs = RHS.CurAbbrevs;
-  for (size_t i = 0, e = CurAbbrevs.size(); i != e; ++i)
-    CurAbbrevs[i]->addRef();
-
-  // Copy block scope and bump ref counts.
-  BlockScope = RHS.BlockScope;
-  for (size_t S = 0, e = BlockScope.size(); S != e; ++S) {
-    std::vector<BitCodeAbbrev*> &Abbrevs = BlockScope[S].PrevAbbrevs;
-    for (size_t i = 0, e = Abbrevs.size(); i != e; ++i)
-      Abbrevs[i]->addRef();
-  }
-}
-
 void BitstreamCursor::freeState() {
   // Free all the Abbrevs.
-  for (size_t i = 0, e = CurAbbrevs.size(); i != e; ++i)
-    CurAbbrevs[i]->dropRef();
   CurAbbrevs.clear();
 
   // Free all the Abbrevs in the block scope.
-  for (size_t S = 0, e = BlockScope.size(); S != e; ++S) {
-    std::vector<BitCodeAbbrev*> &Abbrevs = BlockScope[S].PrevAbbrevs;
-    for (size_t i = 0, e = Abbrevs.size(); i != e; ++i)
-      Abbrevs[i]->dropRef();
-  }
   BlockScope.clear();
 }
 
@@ -63,10 +33,8 @@ bool BitstreamCursor::EnterSubBlock(unsigned BlockID, unsigned *NumWordsP) {
   // Add the abbrevs specific to this block to the CurAbbrevs list.
   if (const BitstreamReader::BlockInfo *Info =
       BitStream->getBlockInfo(BlockID)) {
-    for (size_t i = 0, e = Info->Abbrevs.size(); i != e; ++i) {
-      CurAbbrevs.push_back(Info->Abbrevs[i]);
-      CurAbbrevs.back()->addRef();
-    }
+    CurAbbrevs.insert(CurAbbrevs.end(), Info->Abbrevs.begin(),
+                      Info->Abbrevs.end());
   }
 
   // Get the codesize of this block.
@@ -339,9 +307,8 @@ bool BitstreamCursor::ReadBlockInfoBlock() {
 
       // ReadAbbrevRecord installs the abbrev in CurAbbrevs.  Move it to the
       // appropriate BlockInfo.
-      BitCodeAbbrev *Abbv = CurAbbrevs.back();
+      CurBlockInfo->Abbrevs.push_back(std::move(CurAbbrevs.back()));
       CurAbbrevs.pop_back();
-      CurBlockInfo->Abbrevs.push_back(Abbv);
       continue;
     }