[SourceKit/CursorInfo] Report the set of decls referenced in the symbol graph's "declarationFragments" field.

include/swift/SymbolGraphGen/FragmentInfo.h

@@ -0,0 +1,35 @@
+//===--- FragmentInfo.h - Swift SymbolGraph Declaration Fragment Info -----===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SYMBOLGRAPHGEN_FRAGMENTINFO_H
+#define SWIFT_SYMBOLGRAPHGEN_FRAGMENTINFO_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "PathComponent.h"
+
+namespace swift {
+class ValueDecl;
+
+namespace symbolgraphgen {
+
+/// Summary information for a symbol referenced in a symbol graph declaration fragment.
+struct FragmentInfo {
+  /// The swift decl of the referenced symbol.
+  const ValueDecl *VD;
+  /// The path components of the refereced symbol.
+  SmallVector<PathComponent, 4> ParentContexts;
+};
+
+} // end namespace symbolgraphgen
+} // end namespace swift
+
+#endif // SWIFT_SYMBOLGRAPHGEN_FRAGMENTINFO_H

include/swift/SymbolGraphGen/SymbolGraphGen.h

@@ -17,6 +17,7 @@
 #include "swift/AST/Type.h"
 #include "SymbolGraphOptions.h"
 #include "PathComponent.h"
+#include "FragmentInfo.h"
 
 namespace swift {
 class ValueDecl;
@@ -36,7 +37,8 @@ int printSymbolGraphForDecl(const ValueDecl *D, Type BaseTy,
                             bool InSynthesizedExtension,
                             const SymbolGraphOptions &Options,
                             llvm::raw_ostream &OS,
-                            SmallVectorImpl<PathComponent> &ParentContexts);
+                            SmallVectorImpl<PathComponent> &ParentContexts,
+                            SmallVectorImpl<FragmentInfo> &FragmentInfo);
 
 } // end namespace symbolgraphgen
 } // end namespace swift

lib/SymbolGraphGen/DeclarationFragmentPrinter.cpp

@@ -155,6 +155,8 @@ void DeclarationFragmentPrinter::printTypeRef(Type T, const TypeDecl *RefTo,
   if (ShouldLink) {
     llvm::raw_svector_ostream OS(USR);
     ide::printDeclUSR(RefTo, OS);
+    if (ReferencedDecls)
+      ReferencedDecls->insert(RefTo);
   }
   closeFragment();
 }

lib/SymbolGraphGen/DeclarationFragmentPrinter.h

@@ -13,6 +13,7 @@
 #ifndef SWIFT_SYMBOLGRAPHGEN_DECLARATIONFRAGMENTPRINTER_H
 #define SWIFT_SYMBOLGRAPHGEN_DECLARATIONFRAGMENTPRINTER_H
 
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Support/JSON.h"
 #include "swift/AST/ASTPrinter.h"
 #include "swift/Basic/LLVM.h"
@@ -73,6 +74,9 @@ class DeclarationFragmentPrinter : public ASTPrinter {
 
   SmallString<256> USR;
 
+  /// Stores the set of decls referenced in the fragment if non-null.
+  SmallPtrSet<const Decl*, 8> *ReferencedDecls;
+
   StringRef getKindSpelling(FragmentKind Kind) const;
 
   /// Open a new kind of fragment without committing its spelling.
@@ -86,10 +90,12 @@ class DeclarationFragmentPrinter : public ASTPrinter {
 public:
   DeclarationFragmentPrinter(const SymbolGraph *SG,
                              llvm::json::OStream &OS,
-                             Optional<StringRef> Key = None)
+                             Optional<StringRef> Key = None,
+                             SmallPtrSet<const Decl*, 8> *ReferencedDecls = nullptr)
     : SG(SG),
       OS(OS),
       Kind(FragmentKind::None),
+      ReferencedDecls(ReferencedDecls),
       NumFragments(0) {
     if (Key) {
       OS.attributeBegin(*Key);

lib/SymbolGraphGen/Symbol.cpp

@@ -21,6 +21,7 @@
 #include "Symbol.h"
 #include "SymbolGraph.h"
 #include "SymbolGraphASTWalker.h"
+#include "DeclarationFragmentPrinter.h"
 
 using namespace swift;
 using namespace symbolgraphgen;
@@ -518,6 +519,33 @@ Symbol::getPathComponents(SmallVectorImpl<PathComponent> &Components) const {
   std::reverse(Components.begin(), Components.end());
 }
 
+void Symbol::
+getFragmentInfo(SmallVectorImpl<FragmentInfo> &FragmentInfos) const {
+  SmallPtrSet<const Decl*, 8> Referenced;
+
+  auto Options = Graph->getDeclarationFragmentsPrintOptions();
+  if (getBaseType()) {
+    Options.setBaseType(getBaseType());
+    Options.PrintAsMember = true;
+  }
+
+  llvm::json::OStream OS(llvm::nulls());
+  OS.object([&]{
+    DeclarationFragmentPrinter Printer(Graph, OS, {"ignored"}, &Referenced);
+    getSymbolDecl()->print(Printer, Options);
+  });
+
+  for (auto *D: Referenced) {
+    if (!Symbol::supportsKind(D->getKind()))
+      continue;
+    if (auto *VD = dyn_cast<ValueDecl>(D)) {
+      FragmentInfos.push_back(FragmentInfo{VD, {}});
+      Symbol RefSym(Graph, VD, nullptr);
+      RefSym.getPathComponents(FragmentInfos.back().ParentContexts);
+    }
+  }
+}
+
 void Symbol::printPath(llvm::raw_ostream &OS) const {
   SmallVector<PathComponent, 8> Components;
   getPathComponents(Components);

lib/SymbolGraphGen/Symbol.h

@@ -19,6 +19,7 @@
 #include "swift/Basic/LLVM.h"
 #include "swift/Markup/Markup.h"
 #include "swift/SymbolGraphGen/PathComponent.h"
+#include "swift/SymbolGraphGen/FragmentInfo.h"
 
 namespace swift {
 namespace symbolgraphgen {
@@ -98,8 +99,14 @@ class Symbol {
     return SynthesizedBaseTypeDecl;
   }
 
+  /// Reteive the path components associated with this symbol, from outermost
+  /// to innermost (this symbol).
   void getPathComponents(SmallVectorImpl<PathComponent> &Components) const;
 
+  /// Retrieve information about all symbols referenced in the declaration
+  /// fragment printed for this symbol.
+  void getFragmentInfo(SmallVectorImpl<FragmentInfo> &FragmentInfo) const;
+
   /// Print the symbol path to an output stream.
   void printPath(llvm::raw_ostream &OS) const;
 

lib/SymbolGraphGen/SymbolGraphGen.cpp

@@ -100,7 +100,8 @@ printSymbolGraphForDecl(const ValueDecl *D, Type BaseTy,
                         bool InSynthesizedExtension,
                         const SymbolGraphOptions &Options,
                         llvm::raw_ostream &OS,
-                        SmallVectorImpl<PathComponent> &ParentContexts) {
+                        SmallVectorImpl<PathComponent> &ParentContexts,
+                        SmallVectorImpl<FragmentInfo> &FragmentInfo) {
   if (!Symbol::supportsKind(D->getKind()))
     return EXIT_FAILURE;
 
@@ -116,6 +117,7 @@ printSymbolGraphForDecl(const ValueDecl *D, Type BaseTy,
 
   Symbol MySym(&Graph, D, NTD, BaseTy);
   MySym.getPathComponents(ParentContexts);
+  MySym.getFragmentInfo(FragmentInfo);
   Graph.recordNode(MySym);
   Graph.serialize(JOS);
   return EXIT_SUCCESS;

test/SourceKit/CursorInfo/cursor_symbol_graph_objc.swift

@@ -6,6 +6,7 @@ func callObjC() {
 
 // REQUIRES: objc_interop
 // RUN: %sourcekitd-test -req=cursor -pos=4:3 -req-opts=retrieve_symbol_graph=1 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp -target %target-triple %s | %FileCheck %s
+//
 // CHECK: SYMBOL GRAPH BEGIN
 // CHECK: {
 // CHECK:   "metadata": {