Revert "[NFC] [Serialization] Packing more bits and refactor AbbrevToUse"

This reverts commit 9cdb825.

Author: augusto2112

clang/include/clang/Serialization/ASTReader.h

@@ -2422,8 +2422,6 @@ class BitsUnpacker {
     CurrentBitsIndex = 0;
   }
 
-  void advance(uint32_t BitsWidth) { CurrentBitsIndex += BitsWidth; }
-
   bool getNextBit() {
     assert(isValid());
     return Value & (1 << CurrentBitsIndex++);

clang/include/clang/Serialization/ASTWriter.h

@@ -564,25 +564,11 @@ class ASTWriter : public ASTDeserializationListener,
   unsigned DeclEnumAbbrev = 0;
   unsigned DeclObjCIvarAbbrev = 0;
   unsigned DeclCXXMethodAbbrev = 0;
-  unsigned DeclDependentNonTemplateCXXMethodAbbrev = 0;
-  unsigned DeclTemplateCXXMethodAbbrev = 0;
-  unsigned DeclMemberSpecializedCXXMethodAbbrev = 0;
-  unsigned DeclTemplateSpecializedCXXMethodAbbrev = 0;
-  unsigned DeclDependentSpecializationCXXMethodAbbrev = 0;
-  unsigned DeclTemplateTypeParmAbbrev = 0;
-  unsigned DeclUsingShadowAbbrev = 0;
 
   unsigned DeclRefExprAbbrev = 0;
   unsigned CharacterLiteralAbbrev = 0;
   unsigned IntegerLiteralAbbrev = 0;
   unsigned ExprImplicitCastAbbrev = 0;
-  unsigned BinaryOperatorAbbrev = 0;
-  unsigned CompoundAssignOperatorAbbrev = 0;
-  unsigned CallExprAbbrev = 0;
-  unsigned CXXOperatorCallExprAbbrev = 0;
-  unsigned CXXMemberCallExprAbbrev = 0;
-
-  unsigned CompoundStmtAbbrev = 0;
 
   void WriteDeclAbbrevs();
   void WriteDecl(ASTContext &Context, Decl *D);
@@ -749,42 +735,12 @@ class ASTWriter : public ASTDeserializationListener,
   unsigned getDeclFieldAbbrev() const { return DeclFieldAbbrev; }
   unsigned getDeclEnumAbbrev() const { return DeclEnumAbbrev; }
   unsigned getDeclObjCIvarAbbrev() const { return DeclObjCIvarAbbrev; }
-  unsigned getDeclCXXMethodAbbrev(FunctionDecl::TemplatedKind Kind) const {
-    switch (Kind) {
-    case FunctionDecl::TK_NonTemplate:
-      return DeclCXXMethodAbbrev;
-    case FunctionDecl::TK_FunctionTemplate:
-      return DeclTemplateCXXMethodAbbrev;
-    case FunctionDecl::TK_MemberSpecialization:
-      return DeclMemberSpecializedCXXMethodAbbrev;
-    case FunctionDecl::TK_FunctionTemplateSpecialization:
-      return DeclTemplateSpecializedCXXMethodAbbrev;
-    case FunctionDecl::TK_DependentNonTemplate:
-      return DeclDependentNonTemplateCXXMethodAbbrev;
-    case FunctionDecl::TK_DependentFunctionTemplateSpecialization:
-      return DeclDependentSpecializationCXXMethodAbbrev;
-    default:
-      llvm_unreachable("Unknwon Template Kind!");
-    }
-  }
-  unsigned getDeclTemplateTypeParmAbbrev() const {
-    return DeclTemplateTypeParmAbbrev;
-  }
-  unsigned getDeclUsingShadowAbbrev() const { return DeclUsingShadowAbbrev; }
+  unsigned getDeclCXXMethodAbbrev() const { return DeclCXXMethodAbbrev; }
 
   unsigned getDeclRefExprAbbrev() const { return DeclRefExprAbbrev; }
   unsigned getCharacterLiteralAbbrev() const { return CharacterLiteralAbbrev; }
   unsigned getIntegerLiteralAbbrev() const { return IntegerLiteralAbbrev; }
   unsigned getExprImplicitCastAbbrev() const { return ExprImplicitCastAbbrev; }
-  unsigned getBinaryOperatorAbbrev() const { return BinaryOperatorAbbrev; }
-  unsigned getCompoundAssignOperatorAbbrev() const {
-    return CompoundAssignOperatorAbbrev;
-  }
-  unsigned getCallExprAbbrev() const { return CallExprAbbrev; }
-  unsigned getCXXOperatorCallExprAbbrev() { return CXXOperatorCallExprAbbrev; }
-  unsigned getCXXMemberCallExprAbbrev() { return CXXMemberCallExprAbbrev; }
-
-  unsigned getCompoundStmtAbbrev() const { return CompoundStmtAbbrev; }
 
   bool hasChain() const { return Chain; }
   ASTReader *getChain() const { return Chain; }
@@ -885,33 +841,46 @@ class BitsPacker {
   BitsPacker(BitsPacker &&) = delete;
   BitsPacker operator=(const BitsPacker &) = delete;
   BitsPacker operator=(BitsPacker &&) = delete;
-  ~BitsPacker() = default;
-
-  bool canWriteNextNBits(uint32_t BitsWidth) const {
-    return CurrentBitIndex + BitsWidth < BitIndexUpbound;
-  }
-
-  void reset(uint32_t Value) {
-    UnderlyingValue = Value;
-    CurrentBitIndex = 0;
+  ~BitsPacker() {
+    assert(!hasUnconsumedValues() && "There are unprocessed bits!");
   }
 
   void addBit(bool Value) { addBits(Value, 1); }
   void addBits(uint32_t Value, uint32_t BitsWidth) {
     assert(BitsWidth < BitIndexUpbound);
     assert((Value < (1u << BitsWidth)) && "Passing narrower bit width!");
-    assert(canWriteNextNBits(BitsWidth) &&
-           "Inserting too much bits into a value!");
 
-    UnderlyingValue |= Value << CurrentBitIndex;
+    if (CurrentBitIndex + BitsWidth >= BitIndexUpbound) {
+      Values.push_back(0);
+      CurrentBitIndex = 0;
+    }
+
+    assert(CurrentBitIndex < BitIndexUpbound);
+    Values.back() |= Value << CurrentBitIndex;
     CurrentBitIndex += BitsWidth;
   }
 
-  operator uint32_t() { return UnderlyingValue; }
+  bool hasUnconsumedValues() const {
+    return ConsumingValueIndex < Values.size();
+  }
+  uint32_t getNextValue() {
+    assert(hasUnconsumedValues());
+    return Values[ConsumingValueIndex++];
+  }
+
+  // We can convert the packer to an uint32_t if there is only one values.
+  operator uint32_t() {
+    assert(Values.size() == 1);
+    return getNextValue();
+  }
 
 private:
-  uint32_t UnderlyingValue = 0;
-  uint32_t CurrentBitIndex = 0;
+  SmallVector<uint64_t, 4> Values;
+  uint16_t ConsumingValueIndex = 0;
+  // Initialize CurrentBitIndex with an invalid value
+  // to make it easier to update Values. See the implementation
+  // of `addBits` to see the details.
+  uint16_t CurrentBitIndex = BitIndexUpbound;
 };
 
 } // namespace clang

clang/lib/Serialization/ASTReaderDecl.cpp

@@ -2660,7 +2660,7 @@ void ASTDeclReader::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
 
   D->setDeclaredWithTypename(Record.readInt());
 
-  if (D->hasTypeConstraint()) {
+  if (Record.readBool()) {
     ConceptReference *CR = nullptr;
     if (Record.readBool())
       CR = Record.readConceptReference();