[AST][1/4] Move the bit-fields from TagDecl, EnumDecl and RecordDecl …

…into DeclContext DeclContext has a little less than 8 bytes free due to the alignment requirements on 64 bits archs. This set of patches moves the bit-fields from classes deriving from DeclContext into DeclContext. On 32 bits archs this increases the size of DeclContext by 4 bytes but this is balanced by an equal or larger reduction in the size of the classes deriving from it. On 64 bits archs the size of DeclContext stays the same but most of the classes deriving from it shrink by 8/16 bytes. (-print-stats diff here https://reviews.llvm.org/D49728) When doing an -fsyntax-only on all of Boost this result in a 3.6% reduction in the size of all Decls and a 1% reduction in the run time due to the lower cache miss rate. For now CXXRecordDecl is not touched but there is an easy 6 (if I count correctly) bytes gain available there by moving some bits from DefinitionData into the free space of DeclContext. This will be the subject of another patch. This patch sequence also enable the possibility of refactoring FunctionDecl: To save space some bits from classes deriving from FunctionDecl were moved to FunctionDecl. This resulted in a lot of stuff in FunctionDecl which do not belong logically to it. After this set of patches however it is just a simple matter of adding a SomethingDeclBitfields in DeclContext and moving the bits to it from FunctionDecl. This first patch introduces the anonymous union in DeclContext and all the *DeclBitfields classes holding the bit-fields, and moves the bits from TagDecl, EnumDecl and RecordDecl into DeclContext. This patch is followed by https://reviews.llvm.org/D49732, https://reviews.llvm.org/D49733 and https://reviews.llvm.org/D49734. Differential Revision: https://reviews.llvm.org/D49729 Patch By: bricci llvm-svn: 338630
llvm · Aug 1, 2018 · f92f31c · f92f31c
1 parent 7f33094
commit f92f31c
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Showing 9 changed files with 775 additions and 312 deletions.
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
diff --git a/clang/include/clang/AST/DeclBase.h b/clang/include/clang/AST/DeclBase.h
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
@@ -3767,6 +3767,22 @@ void FieldDecl::setCapturedVLAType(const VariableArrayType *VLAType) {
 // TagDecl Implementation
 //===----------------------------------------------------------------------===//
 
+TagDecl::TagDecl(Kind DK, TagKind TK, const ASTContext &C, DeclContext *DC,
+                 SourceLocation L, IdentifierInfo *Id, TagDecl *PrevDecl,
+                 SourceLocation StartL)
+    : TypeDecl(DK, DC, L, Id, StartL), DeclContext(DK), redeclarable_base(C),
+      TypedefNameDeclOrQualifier((TypedefNameDecl *)nullptr) {
+  assert((DK != Enum || TK == TTK_Enum) &&
+         "EnumDecl not matched with TTK_Enum");
+  setPreviousDecl(PrevDecl);
+  setTagKind(TK);
+  setCompleteDefinition(false);
+  setBeingDefined(false);
+  setEmbeddedInDeclarator(false);
+  setFreeStanding(false);
+  setCompleteDefinitionRequired(false);
+}
+
 SourceLocation TagDecl::getOuterLocStart() const {
   return getTemplateOrInnerLocStart(this);
 }
@@ -3789,7 +3805,7 @@ void TagDecl::setTypedefNameForAnonDecl(TypedefNameDecl *TDD) {
 }
 
 void TagDecl::startDefinition() {
-  IsBeingDefined = true;
+  setBeingDefined(true);
 
   if (auto *D = dyn_cast<CXXRecordDecl>(this)) {
     struct CXXRecordDecl::DefinitionData *Data =
@@ -3804,8 +3820,8 @@ void TagDecl::completeDefinition() {
           cast<CXXRecordDecl>(this)->hasDefinition()) &&
          "definition completed but not started");
 
-  IsCompleteDefinition = true;
-  IsBeingDefined = false;
+  setCompleteDefinition(true);
+  setBeingDefined(false);
 
   if (ASTMutationListener *L = getASTMutationListener())
     L->CompletedTagDefinition(this);
@@ -3816,7 +3832,7 @@ TagDecl *TagDecl::getDefinition() const {
     return const_cast<TagDecl *>(this);
 
   // If it's possible for us to have an out-of-date definition, check now.
-  if (MayHaveOutOfDateDef) {
+  if (mayHaveOutOfDateDef()) {
     if (IdentifierInfo *II = getIdentifier()) {
       if (II->isOutOfDate()) {
         updateOutOfDate(*II);
@@ -3869,6 +3885,21 @@ void TagDecl::setTemplateParameterListsInfo(
 // EnumDecl Implementation
 //===----------------------------------------------------------------------===//
 
+EnumDecl::EnumDecl(ASTContext &C, DeclContext *DC, SourceLocation StartLoc,
+                   SourceLocation IdLoc, IdentifierInfo *Id, EnumDecl *PrevDecl,
+                   bool Scoped, bool ScopedUsingClassTag, bool Fixed)
+    : TagDecl(Enum, TTK_Enum, C, DC, IdLoc, Id, PrevDecl, StartLoc) {
+  assert(Scoped || !ScopedUsingClassTag);
+  IntegerType = nullptr;
+  setNumPositiveBits(0);
+  setNumNegativeBits(0);
+  setScoped(Scoped);
+  setScopedUsingClassTag(ScopedUsingClassTag);
+  setFixed(Fixed);
+  setHasODRHash(false);
+  ODRHash = 0;
+}
+
 void EnumDecl::anchor() {}
 
 EnumDecl *EnumDecl::Create(ASTContext &C, DeclContext *DC,
@@ -3878,7 +3909,7 @@ EnumDecl *EnumDecl::Create(ASTContext &C, DeclContext *DC,
                            bool IsScopedUsingClassTag, bool IsFixed) {
   auto *Enum = new (C, DC) EnumDecl(C, DC, StartLoc, IdLoc, Id, PrevDecl,
                                     IsScoped, IsScopedUsingClassTag, IsFixed);
-  Enum->MayHaveOutOfDateDef = C.getLangOpts().Modules;
+  Enum->setMayHaveOutOfDateDef(C.getLangOpts().Modules);
   C.getTypeDeclType(Enum, PrevDecl);
   return Enum;
 }
@@ -3887,7 +3918,7 @@ EnumDecl *EnumDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
   EnumDecl *Enum =
       new (C, ID) EnumDecl(C, nullptr, SourceLocation(), SourceLocation(),
                            nullptr, nullptr, false, false, false);
-  Enum->MayHaveOutOfDateDef = C.getLangOpts().Modules;
+  Enum->setMayHaveOutOfDateDef(C.getLangOpts().Modules);
   return Enum;
 }
 
@@ -3971,12 +4002,12 @@ void EnumDecl::setInstantiationOfMemberEnum(ASTContext &C, EnumDecl *ED,
 }
 
 unsigned EnumDecl::getODRHash() {
-  if (HasODRHash)
+  if (hasODRHash())
     return ODRHash;
 
   class ODRHash Hash;
   Hash.AddEnumDecl(this);
-  HasODRHash = true;
+  setHasODRHash(true);
   ODRHash = Hash.CalculateHash();
   return ODRHash;
 }
@@ -3989,22 +4020,26 @@ RecordDecl::RecordDecl(Kind DK, TagKind TK, const ASTContext &C,
                        DeclContext *DC, SourceLocation StartLoc,
                        SourceLocation IdLoc, IdentifierInfo *Id,
                        RecordDecl *PrevDecl)
-    : TagDecl(DK, TK, C, DC, IdLoc, Id, PrevDecl, StartLoc),
-      HasFlexibleArrayMember(false), AnonymousStructOrUnion(false),
-      HasObjectMember(false), HasVolatileMember(false),
-      LoadedFieldsFromExternalStorage(false),
-      NonTrivialToPrimitiveDefaultInitialize(false),
-      NonTrivialToPrimitiveCopy(false), NonTrivialToPrimitiveDestroy(false),
-      ParamDestroyedInCallee(false), ArgPassingRestrictions(APK_CanPassInRegs) {
-  assert(classof(static_cast<Decl*>(this)) && "Invalid Kind!");
+    : TagDecl(DK, TK, C, DC, IdLoc, Id, PrevDecl, StartLoc) {
+  assert(classof(static_cast<Decl *>(this)) && "Invalid Kind!");
+  setHasFlexibleArrayMember(false);
+  setAnonymousStructOrUnion(false);
+  setHasObjectMember(false);
+  setHasVolatileMember(false);
+  setHasLoadedFieldsFromExternalStorage(false);
+  setNonTrivialToPrimitiveDefaultInitialize(false);
+  setNonTrivialToPrimitiveCopy(false);
+  setNonTrivialToPrimitiveDestroy(false);
+  setParamDestroyedInCallee(false);
+  setArgPassingRestrictions(APK_CanPassInRegs);
 }
 
 RecordDecl *RecordDecl::Create(const ASTContext &C, TagKind TK, DeclContext *DC,
                                SourceLocation StartLoc, SourceLocation IdLoc,
                                IdentifierInfo *Id, RecordDecl* PrevDecl) {
   RecordDecl *R = new (C, DC) RecordDecl(Record, TK, C, DC,
                                          StartLoc, IdLoc, Id, PrevDecl);
-  R->MayHaveOutOfDateDef = C.getLangOpts().Modules;
+  R->setMayHaveOutOfDateDef(C.getLangOpts().Modules);
 
   C.getTypeDeclType(R, PrevDecl);
   return R;
@@ -4014,7 +4049,7 @@ RecordDecl *RecordDecl::CreateDeserialized(const ASTContext &C, unsigned ID) {
   RecordDecl *R =
       new (C, ID) RecordDecl(Record, TTK_Struct, C, nullptr, SourceLocation(),
                              SourceLocation(), nullptr, nullptr);
-  R->MayHaveOutOfDateDef = C.getLangOpts().Modules;
+  R->setMayHaveOutOfDateDef(C.getLangOpts().Modules);
   return R;
 }
 
@@ -4038,7 +4073,7 @@ void RecordDecl::setCapturedRecord() {
 }
 
 RecordDecl::field_iterator RecordDecl::field_begin() const {
-  if (hasExternalLexicalStorage() && !LoadedFieldsFromExternalStorage)
+  if (hasExternalLexicalStorage() && !hasLoadedFieldsFromExternalStorage())
     LoadFieldsFromExternalStorage();
 
   return field_iterator(decl_iterator(FirstDecl));
@@ -4066,7 +4101,7 @@ void RecordDecl::LoadFieldsFromExternalStorage() const {
   ExternalASTSource::Deserializing TheFields(Source);
 
   SmallVector<Decl*, 64> Decls;
-  LoadedFieldsFromExternalStorage = true;
+  setHasLoadedFieldsFromExternalStorage(true);
   Source->FindExternalLexicalDecls(this, [](Decl::Kind K) {
     return FieldDecl::classofKind(K) || IndirectFieldDecl::classofKind(K);
   }, Decls);