[lldb][ExpressionParser][NFC] Implement CompleteRedeclChain APIs

(cherry picked from commit 5a2f2f397796affd598011772ec1880ff8841093)

Author: Michael137

lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp

@@ -22,6 +22,7 @@
 #include "lldb/Utility/Log.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/RecordLayout.h"
+#include "clang/AST/Type.h"
 #include "clang/Basic/SourceManager.h"
 
 #include "Plugins/ExpressionParser/Clang/ClangUtil.h"
@@ -327,6 +328,45 @@ void ClangASTSource::CompleteType(clang::ObjCInterfaceDecl *interface_decl) {
   LLDB_LOG(log, "      [COID] {0}", ClangUtil::DumpDecl(interface_decl));
 }
 
+void ClangASTSource::CompleteRedeclChain(const Decl *d) {
+  if (!TypeSystemClang::UseRedeclCompletion())
+    return;
+
+  if (const clang::TagDecl *td = llvm::dyn_cast<TagDecl>(d)) {
+    if (td->isBeingDefined())
+      return;
+
+    if (td->getDefinition())
+      return;
+
+    m_ast_importer_sp->CompleteTagDecl(const_cast<clang::TagDecl *>(td));
+    if (!td->getDefinition() && m_ast_importer_sp->GetDeclOrigin(td).Valid()) {
+      if (TagDecl *alternate = FindCompleteType(td))
+        m_ast_importer_sp->CompleteTagDeclWithOrigin(
+            const_cast<clang::TagDecl *>(td), alternate);
+    }
+  }
+  if (const auto *od = llvm::dyn_cast<ObjCInterfaceDecl>(d)) {
+    ClangASTImporter::DeclOrigin original =
+        m_ast_importer_sp->GetDeclOrigin(od);
+    if (ObjCInterfaceDecl *orig =
+            dyn_cast_or_null<ObjCInterfaceDecl>(original.decl)) {
+      if (ObjCInterfaceDecl *i = GetCompleteObjCInterface(orig)) {
+        if (i != orig) {
+          m_ast_importer_sp->SetDeclOrigin(d, i);
+          m_ast_importer_sp->CompleteObjCInterfaceDecl(
+              const_cast<clang::ObjCInterfaceDecl *>(od));
+          return;
+        }
+      }
+    }
+    if (od->getDefinition())
+      return;
+    m_ast_importer_sp->CompleteObjCInterfaceDecl(
+        const_cast<clang::ObjCInterfaceDecl *>(od));
+  }
+}
+
 clang::ObjCInterfaceDecl *ClangASTSource::GetCompleteObjCInterface(
     const clang::ObjCInterfaceDecl *interface_decl) {
   lldb::ProcessSP process(m_target->GetProcessSP());

lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h

@@ -154,6 +154,8 @@ class ClangASTSource : public ImporterBackedASTSource,
   ///     The Decl to be completed in place.
   void CompleteType(clang::ObjCInterfaceDecl *Class) override;
 
+  void CompleteRedeclChain(clang::Decl const *D) override;
+
   /// Called on entering a translation unit.  Tells Clang by calling
   /// setHasExternalVisibleStorage() and setHasExternalLexicalStorage() that
   /// this object has something to say about undefined names.
@@ -232,6 +234,10 @@ class ClangASTSource : public ImporterBackedASTSource,
       return m_original.CompleteType(Class);
     }
 
+    void CompleteRedeclChain(clang::Decl const *D) override {
+      return m_original.CompleteRedeclChain(D);
+    }
+
     bool layoutRecordType(
         const clang::RecordDecl *Record, uint64_t &Size, uint64_t &Alignment,
         llvm::DenseMap<const clang::FieldDecl *, uint64_t> &FieldOffsets,

lldb/source/Plugins/ExpressionParser/Clang/ClangExternalASTSourceCallbacks.cpp

@@ -26,6 +26,25 @@ void ClangExternalASTSourceCallbacks::CompleteType(
   m_ast.CompleteObjCInterfaceDecl(objc_decl);
 }
 
+void ClangExternalASTSourceCallbacks::CompleteRedeclChain(
+    const clang::Decl *d) {
+  if (!TypeSystemClang::UseRedeclCompletion())
+    return;
+
+  if (const clang::TagDecl *td = llvm::dyn_cast<clang::TagDecl>(d)) {
+    if (td->isBeingDefined())
+      return;
+    if (td->getDefinition())
+      return;
+    m_ast.CompleteTagDecl(const_cast<clang::TagDecl *>(td));
+  }
+  if (const auto *od = llvm::dyn_cast<clang::ObjCInterfaceDecl>(d)) {
+    if (od->getDefinition())
+      return;
+    m_ast.CompleteObjCInterfaceDecl(const_cast<clang::ObjCInterfaceDecl *>(od));
+  }
+}
+
 bool ClangExternalASTSourceCallbacks::layoutRecordType(
     const clang::RecordDecl *Record, uint64_t &Size, uint64_t &Alignment,
     llvm::DenseMap<const clang::FieldDecl *, uint64_t> &FieldOffsets,

lldb/source/Plugins/ExpressionParser/Clang/ClangExternalASTSourceCallbacks.h

@@ -41,6 +41,8 @@ class ClangExternalASTSourceCallbacks : public ImporterBackedASTSource {
 
   void CompleteType(clang::ObjCInterfaceDecl *objc_decl) override;
 
+  void CompleteRedeclChain(clang::Decl const *D) override;
+
   bool layoutRecordType(
       const clang::RecordDecl *Record, uint64_t &Size, uint64_t &Alignment,
       llvm::DenseMap<const clang::FieldDecl *, uint64_t> &FieldOffsets,

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp

@@ -109,6 +109,15 @@ class lldb_private::AppleObjCExternalASTSource
     }
   }
 
+  void CompleteRedeclChain(const clang::Decl *d) override {
+    using namespace clang;
+    auto *const_interface = llvm::dyn_cast<ObjCInterfaceDecl>(d);
+    if (!const_interface)
+      return;
+    auto *interface = const_cast<ObjCInterfaceDecl *>(const_interface);
+    m_decl_vendor.FinishDecl(interface);
+  }
+
   bool layoutRecordType(
       const clang::RecordDecl *Record, uint64_t &Size, uint64_t &Alignment,
       llvm::DenseMap<const clang::FieldDecl *, uint64_t> &FieldOffsets,