[clang][ExtractAPI] Reland ExtractAPI for libclang improvements

This relands the changes that were originally introduced by:
- https://reviews.llvm.org/D146656
- https://reviews.llvm.org/D147138

This also fixes the leak that led to these changes being reverted

Differential Revision: https://reviews.llvm.org/D147234

Author: daniel-grumberg

clang/include/clang/ExtractAPI/ExtractAPIVisitor.h

@@ -7,7 +7,6 @@ add_clang_library(clangExtractAPI
   APIIgnoresList.cpp
   AvailabilityInfo.cpp
   ExtractAPIConsumer.cpp
-  ExtractAPIVisitor.cpp
   DeclarationFragments.cpp
   Serialization/SerializerBase.cpp
   Serialization/SymbolGraphSerializer.cpp

clang/lib/ExtractAPI/TypedefUnderlyingTypeResolver.h renamed to clang/include/clang/ExtractAPI/TypedefUnderlyingTypeResolver.h

@@ -12,7 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/ExtractAPI/DeclarationFragments.h"
-#include "TypedefUnderlyingTypeResolver.h"
+#include "clang/ExtractAPI/TypedefUnderlyingTypeResolver.h"
 #include "clang/Index/USRGeneration.h"
 #include "llvm/ADT/StringSwitch.h"
 

clang/lib/ExtractAPI/CMakeLists.txt

@@ -12,8 +12,10 @@
 ///
 //===----------------------------------------------------------------------===//
 
+#include "clang/AST/ASTConcept.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclObjC.h"
 #include "clang/Basic/DiagnosticFrontend.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
@@ -33,6 +35,7 @@
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Casting.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -218,19 +221,42 @@ struct LocationFileChecker {
   llvm::DenseSet<const FileEntry *> ExternalFileEntries;
 };
 
+struct BatchExtractAPIVisitor : ExtractAPIVisitor<BatchExtractAPIVisitor> {
+  bool shouldDeclBeIncluded(const Decl *D) const {
+    bool ShouldBeIncluded = true;
+    // Check that we have the definition for redeclarable types.
+    if (auto *TD = llvm::dyn_cast<TagDecl>(D))
+      ShouldBeIncluded = TD->isThisDeclarationADefinition();
+    else if (auto *Interface = llvm::dyn_cast<ObjCInterfaceDecl>(D))
+      ShouldBeIncluded = Interface->isThisDeclarationADefinition();
+    else if (auto *Protocol = llvm::dyn_cast<ObjCProtocolDecl>(D))
+      ShouldBeIncluded = Protocol->isThisDeclarationADefinition();
+
+    ShouldBeIncluded = ShouldBeIncluded && LCF(D->getLocation());
+    return ShouldBeIncluded;
+  }
+
+  BatchExtractAPIVisitor(LocationFileChecker &LCF, ASTContext &Context,
+                         APISet &API)
+      : ExtractAPIVisitor<BatchExtractAPIVisitor>(Context, API), LCF(LCF) {}
+
+private:
+  LocationFileChecker &LCF;
+};
+
 class ExtractAPIConsumer : public ASTConsumer {
 public:
   ExtractAPIConsumer(ASTContext &Context,
                      std::unique_ptr<LocationFileChecker> LCF, APISet &API)
-      : Visitor(Context, *LCF, API), LCF(std::move(LCF)) {}
+      : Visitor(*LCF, Context, API), LCF(std::move(LCF)) {}
 
   void HandleTranslationUnit(ASTContext &Context) override {
     // Use ExtractAPIVisitor to traverse symbol declarations in the context.
     Visitor.TraverseDecl(Context.getTranslationUnitDecl());
   }
 
 private:
-  ExtractAPIVisitor Visitor;
+  BatchExtractAPIVisitor Visitor;
   std::unique_ptr<LocationFileChecker> LCF;
 };