Revert "Cherry-pick "[Modules] Record whether VarDecl initializers contain side effects (llvm#143739)"" (llvm#10945)

Author: hnrklssn

clang/include/clang/AST/Decl.h

@@ -1339,11 +1339,6 @@ class VarDecl : public DeclaratorDecl, public Redeclarable<VarDecl> {
     return const_cast<VarDecl *>(this)->getInitializingDeclaration();
   }
 
-  /// Checks whether this declaration has an initializer with side effects,
-  /// without triggering deserialization if the initializer is not yet
-  /// deserialized.
-  bool hasInitWithSideEffects() const;
-
   /// Determine whether this variable's value might be usable in a
   /// constant expression, according to the relevant language standard.
   /// This only checks properties of the declaration, and does not check

clang/include/clang/AST/ExternalASTSource.h

@@ -51,7 +51,6 @@ class RecordDecl;
 class Selector;
 class Stmt;
 class TagDecl;
-class VarDecl;
 
 /// Abstract interface for external sources of AST nodes.
 ///
@@ -174,10 +173,6 @@ class ExternalASTSource : public RefCountedBase<ExternalASTSource> {
 
   virtual ExtKind hasExternalDefinitions(const Decl *D);
 
-  virtual bool hasInitializerWithSideEffects(const VarDecl *VD) const {
-    return false;
-  }
-
   /// Finds all declarations lexically contained within the given
   /// DeclContext, after applying an optional filter predicate.
   ///
@@ -412,17 +407,6 @@ struct LazyOffsetPtr {
     return GetPtr();
   }
 
-  /// Retrieve the pointer to the AST node that this lazy pointer points to,
-  /// if it can be done without triggering deserialization.
-  ///
-  /// \returns a pointer to the AST node, or null if not yet deserialized.
-  T *getWithoutDeserializing() const {
-    if (isOffset()) {
-      return nullptr;
-    }
-    return GetPtr();
-  }
-
   /// Retrieve the address of the AST node pointer. Deserializes the pointee if
   /// necessary.
   T **getAddressOfPointer(ExternalASTSource *Source) const {

clang/include/clang/Sema/MultiplexExternalSemaSource.h

@@ -92,8 +92,6 @@ class MultiplexExternalSemaSource : public ExternalSemaSource {
 
   ExtKind hasExternalDefinitions(const Decl *D) override;
 
-  bool hasInitializerWithSideEffects(const VarDecl *VD) const override;
-
   /// Find all declarations with the given name in the
   /// given context.
   bool FindExternalVisibleDeclsByName(const DeclContext *DC,

clang/include/clang/Serialization/ASTReader.h

@@ -1348,12 +1348,6 @@ class ASTReader
     const StringRef &operator*() && = delete;
   };
 
-  /// VarDecls with initializers containing side effects must be emitted,
-  /// but DeclMustBeEmitted is not allowed to deserialize the intializer.
-  /// FIXME: Lower memory usage by removing VarDecls once the initializer
-  /// is deserialized.
-  llvm::SmallPtrSet<Decl *, 16> InitSideEffectVars;
-
 public:
   /// Get the buffer for resolving paths.
   SmallString<0> &getPathBuf() { return PathBuf; }
@@ -2269,8 +2263,6 @@ class ASTReader
 
   ExtKind hasExternalDefinitions(const Decl *D) override;
 
-  bool hasInitializerWithSideEffects(const VarDecl *VD) const override;
-
   /// Retrieve a selector from the given module with its local ID
   /// number.
   Selector getLocalSelector(ModuleFile &M, unsigned LocalID);

clang/lib/AST/ASTContext.cpp

@@ -13262,7 +13262,9 @@ bool ASTContext::DeclMustBeEmitted(const Decl *D) {
     return true;
 
   // Variables that have initialization with side-effects are required.
-  if (VD->hasInitWithSideEffects())
+  if (VD->getInit() && VD->getInit()->HasSideEffects(*this) &&
+      // We can get a value-dependent initializer during error recovery.
+      (VD->getInit()->isValueDependent() || !VD->evaluateValue()))
     return true;
 
   // Likewise, variables with tuple-like bindings are required if their

clang/lib/AST/Decl.cpp

@@ -2440,30 +2440,6 @@ VarDecl *VarDecl::getInitializingDeclaration() {
   return Def;
 }
 
-bool VarDecl::hasInitWithSideEffects() const {
-  if (!hasInit())
-    return false;
-
-  // Check if we can get the initializer without deserializing
-  const Expr *E = nullptr;
-  if (auto *S = dyn_cast<Stmt *>(Init)) {
-    E = cast<Expr>(S);
-  } else {
-    E = cast_or_null<Expr>(getEvaluatedStmt()->Value.getWithoutDeserializing());
-  }
-
-  if (E)
-    return E->HasSideEffects(getASTContext()) &&
-           // We can get a value-dependent initializer during error recovery.
-           (E->isValueDependent() || !evaluateValue());
-
-  assert(getEvaluatedStmt()->Value.isOffset());
-  // ASTReader tracks this without having to deserialize the initializer
-  if (auto Source = getASTContext().getExternalSource())
-    return Source->hasInitializerWithSideEffects(this);
-  return false;
-}
-
 bool VarDecl::isOutOfLine() const {
   if (Decl::isOutOfLine())
     return true;

clang/lib/AST/ExprConstant.cpp

@@ -16268,12 +16268,6 @@ static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
                             const Expr *E, bool AllowNonLiteralTypes) {
   assert(!E->isValueDependent());
 
-  // Normally expressions passed to EvaluateInPlace have a type, but not when
-  // a VarDecl initializer is evaluated before the untyped ParenListExpr is
-  // replaced with a CXXConstructExpr. This can happen in LLDB.
-  if (E->getType().isNull())
-    return false;
-
   if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
     return false;
 

clang/lib/Sema/MultiplexExternalSemaSource.cpp

@@ -107,14 +107,6 @@ MultiplexExternalSemaSource::hasExternalDefinitions(const Decl *D) {
   return EK_ReplyHazy;
 }
 
-bool MultiplexExternalSemaSource::hasInitializerWithSideEffects(
-    const VarDecl *VD) const {
-  for (const auto &S : Sources)
-    if (S->hasInitializerWithSideEffects(VD))
-      return true;
-  return false;
-}
-
 bool MultiplexExternalSemaSource::
 FindExternalVisibleDeclsByName(const DeclContext *DC, DeclarationName Name) {
   bool AnyDeclsFound = false;

clang/lib/Serialization/ASTReader.cpp

@@ -9268,10 +9268,6 @@ ExternalASTSource::ExtKind ASTReader::hasExternalDefinitions(const Decl *FD) {
   return I->second ? EK_Never : EK_Always;
 }
 
-bool ASTReader::hasInitializerWithSideEffects(const VarDecl *VD) const {
-  return InitSideEffectVars.count(VD);
-}
-
 Selector ASTReader::getLocalSelector(ModuleFile &M, unsigned LocalID) {
   return DecodeSelector(getGlobalSelectorID(M, LocalID));
 }

clang/lib/Serialization/ASTReaderDecl.cpp

@@ -1622,9 +1622,6 @@ ASTDeclReader::RedeclarableResult ASTDeclReader::VisitVarDeclImpl(VarDecl *VD) {
     VD->NonParmVarDeclBits.PreviousDeclInSameBlockScope =
         VarDeclBits.getNextBit();
 
-    if (VarDeclBits.getNextBit())
-      Reader.InitSideEffectVars.insert(VD);
-
     VD->NonParmVarDeclBits.EscapingByref = VarDeclBits.getNextBit();
     HasDeducedType = VarDeclBits.getNextBit();
     VD->NonParmVarDeclBits.ImplicitParamKind =