[clang][ExtractAPI] Visit method templates with better scheme

Visit and serialize method templates and template specializations. Introduces a new scheme of visiting child Decls via VisitCXXMethodDecl which will be followed in future patches for Fields and non-template methods.

Depends on D157579

Reviewed By: dang

Differential Revision: https://reviews.llvm.org/D158027

clang/include/clang/ExtractAPI/API.h

@@ -180,6 +180,8 @@ struct APIRecord {
     RK_CXXInstanceMethod,
     RK_CXXConstructorMethod,
     RK_CXXDestructorMethod,
+    RK_CXXMethodTemplate,
+    RK_CXXMethodTemplateSpecialization,
     RK_ObjCInstanceProperty,
     RK_ObjCClassProperty,
     RK_ObjCIvar,
@@ -623,6 +625,42 @@ private:
   virtual void anchor();
 };
 
+struct CXXMethodTemplateRecord : CXXMethodRecord {
+  Template Templ;
+
+  CXXMethodTemplateRecord(StringRef USR, StringRef Name, PresumedLoc Loc,
+                          AvailabilitySet Availabilities,
+                          const DocComment &Comment,
+                          DeclarationFragments Declaration,
+                          DeclarationFragments SubHeading,
+                          FunctionSignature Signature, AccessControl Access,
+                          Template Template, bool IsFromSystemHeader)
+      : CXXMethodRecord(RK_CXXMethodTemplate, USR, Name, Loc,
+                        std::move(Availabilities), Comment, Declaration,
+                        SubHeading, Signature, Access, IsFromSystemHeader),
+        Templ(Template) {}
+
+  static bool classof(const APIRecord *Record) {
+    return Record->getKind() == RK_CXXMethodTemplate;
+  }
+};
+
+struct CXXMethodTemplateSpecializationRecord : CXXMethodRecord {
+  CXXMethodTemplateSpecializationRecord(
+      StringRef USR, StringRef Name, PresumedLoc Loc,
+      AvailabilitySet Availabilities, const DocComment &Comment,
+      DeclarationFragments Declaration, DeclarationFragments SubHeading,
+      FunctionSignature Signature, AccessControl Access,
+      bool IsFromSystemHeader)
+      : CXXMethodRecord(RK_CXXMethodTemplateSpecialization, USR, Name, Loc,
+                        std::move(Availabilities), Comment, Declaration,
+                        SubHeading, Signature, Access, IsFromSystemHeader) {}
+
+  static bool classof(const APIRecord *Record) {
+    return Record->getKind() == RK_CXXMethodTemplateSpecialization;
+  }
+};
+
 /// This holds information associated with Objective-C properties.
 struct ObjCPropertyRecord : APIRecord {
   /// The attributes associated with an Objective-C property.
@@ -794,6 +832,8 @@ struct SymbolReference {
       : Name(Name), USR(USR), Source(Source) {}
   SymbolReference(const APIRecord &Record)
       : Name(Record.Name), USR(Record.USR) {}
+  SymbolReference(const APIRecord *Record)
+      : Name(Record->Name), USR(Record->USR) {}
 
   /// Determine if this SymbolReference is empty.
   ///
@@ -1058,10 +1098,21 @@ template <>
 struct has_function_signature<ObjCClassMethodRecord> : public std::true_type {};
 template <>
 struct has_function_signature<CXXMethodRecord> : public std::true_type {};
+template <>
+struct has_function_signature<CXXMethodTemplateRecord> : public std::true_type {
+};
+template <>
+struct has_function_signature<CXXMethodTemplateSpecializationRecord>
+    : public std::true_type {};
 
 template <typename RecordTy> struct has_access : public std::false_type {};
 template <> struct has_access<CXXMethodRecord> : public std::true_type {};
 template <> struct has_access<CXXFieldRecord> : public std::true_type {};
+template <>
+struct has_access<CXXMethodTemplateRecord> : public std::true_type {};
+template <>
+struct has_access<CXXMethodTemplateSpecializationRecord>
+    : public std::true_type {};
 
 template <typename RecordTy> struct has_template : public std::false_type {};
 template <> struct has_template<ClassTemplateRecord> : public std::true_type {};
@@ -1074,6 +1125,8 @@ struct has_template<GlobalVariableTemplateRecord> : public std::true_type {};
 template <>
 struct has_template<GlobalVariableTemplatePartialSpecializationRecord>
     : public std::true_type {};
+template <>
+struct has_template<CXXMethodTemplateRecord> : public std::true_type {};
 
 template <>
 struct has_template<GlobalFunctionTemplateRecord> : public std::true_type {};
@@ -1253,6 +1306,20 @@ public:
       FunctionSignature Signature, bool IsConstructor, AccessControl Access,
       bool IsFromSystemHeader);
 
+  CXXMethodTemplateRecord *addCXXMethodTemplate(
+      APIRecord *Parent, StringRef Name, StringRef USR, PresumedLoc Loc,
+      AvailabilitySet Availability, const DocComment &Comment,
+      DeclarationFragments Declaration, DeclarationFragments SubHeading,
+      FunctionSignature Signature, AccessControl Access, Template Template,
+      bool IsFromSystemHeader);
+
+  CXXMethodTemplateSpecializationRecord *addCXXMethodTemplateSpec(
+      APIRecord *Parent, StringRef Name, StringRef USR, PresumedLoc Loc,
+      AvailabilitySet Availability, const DocComment &Comment,
+      DeclarationFragments Declaration, DeclarationFragments SubHeading,
+      FunctionSignature Signature, AccessControl Access,
+      bool IsFromSystemHeader);
+
   ConceptRecord *addConcept(StringRef Name, StringRef USR, PresumedLoc Loc,
                             AvailabilitySet Availability,
                             const DocComment &Comment,
@@ -1408,6 +1475,13 @@ public:
   const RecordMap<EnumRecord> &getEnums() const { return Enums; }
   const RecordMap<StructRecord> &getStructs() const { return Structs; }
   const RecordMap<CXXClassRecord> &getCXXClasses() const { return CXXClasses; }
+  const RecordMap<CXXMethodTemplateRecord> &getCXXMethodTemplates() const {
+    return CXXMethodTemplates;
+  }
+  const RecordMap<CXXMethodTemplateSpecializationRecord> &
+  getCXXMethodTemplateSpecializations() const {
+    return CXXMethodTemplateSpecializations;
+  }
   const RecordMap<ConceptRecord> &getConcepts() const { return Concepts; }
   const RecordMap<ClassTemplateRecord> &getClassTemplates() const {
     return ClassTemplates;
@@ -1487,6 +1561,9 @@ private:
   RecordMap<EnumRecord> Enums;
   RecordMap<StructRecord> Structs;
   RecordMap<CXXClassRecord> CXXClasses;
+  RecordMap<CXXMethodTemplateRecord> CXXMethodTemplates;
+  RecordMap<CXXMethodTemplateSpecializationRecord>
+      CXXMethodTemplateSpecializations;
   RecordMap<ClassTemplateRecord> ClassTemplates;
   RecordMap<ClassTemplateSpecializationRecord> ClassTemplateSpecializations;
   RecordMap<ClassTemplatePartialSpecializationRecord>

clang/include/clang/ExtractAPI/ExtractAPIVisitor.h

@@ -27,6 +27,7 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/ExtractAPI/API.h"
 #include "clang/ExtractAPI/TypedefUnderlyingTypeResolver.h"
+#include "clang/Index/USRGeneration.h"
 #include "llvm/ADT/StringRef.h"
 #include <type_traits>
 
@@ -53,6 +54,8 @@ public:
 
   bool WalkUpFromCXXRecordDecl(const CXXRecordDecl *Decl);
 
+  bool WalkUpFromCXXMethodDecl(const CXXMethodDecl *Decl);
+
   bool WalkUpFromClassTemplateSpecializationDecl(
       const ClassTemplateSpecializationDecl *Decl);
 
@@ -73,6 +76,8 @@ public:
 
   bool VisitCXXRecordDecl(const CXXRecordDecl *Decl);
 
+  bool VisitCXXMethodDecl(const CXXMethodDecl *Decl);
+
   bool VisitConceptDecl(const ConceptDecl *Decl);
 
   bool VisitClassTemplateSpecializationDecl(
@@ -287,11 +292,11 @@ bool ExtractAPIVisitorBase<Derived>::VisitFunctionDecl(
   switch (Decl->getTemplatedKind()) {
   case FunctionDecl::TK_NonTemplate:
   case FunctionDecl::TK_DependentNonTemplate:
-  case FunctionDecl::TK_MemberSpecialization:
   case FunctionDecl::TK_FunctionTemplateSpecialization:
     break;
   case FunctionDecl::TK_FunctionTemplate:
   case FunctionDecl::TK_DependentFunctionTemplateSpecialization:
+  case FunctionDecl::TK_MemberSpecialization:
     return true;
   }
 
@@ -387,6 +392,13 @@ bool ExtractAPIVisitorBase<Derived>::WalkUpFromCXXRecordDecl(
   return true;
 }
 
+template <typename Derived>
+bool ExtractAPIVisitorBase<Derived>::WalkUpFromCXXMethodDecl(
+    const CXXMethodDecl *Decl) {
+  getDerivedExtractAPIVisitor().VisitCXXMethodDecl(Decl);
+  return true;
+}
+
 template <typename Derived>
 bool ExtractAPIVisitorBase<Derived>::WalkUpFromClassTemplateSpecializationDecl(
     const ClassTemplateSpecializationDecl *Decl) {
@@ -521,6 +533,60 @@ bool ExtractAPIVisitorBase<Derived>::VisitCXXRecordDecl(
   return true;
 }
 
+template <typename Derived>
+bool ExtractAPIVisitorBase<Derived>::VisitCXXMethodDecl(
+    const CXXMethodDecl *Decl) {
+  if (!getDerivedExtractAPIVisitor().shouldDeclBeIncluded(Decl) ||
+      Decl->isImplicit())
+    return true;
+  switch (Decl->getTemplatedKind()) {
+  case FunctionDecl::TK_MemberSpecialization:
+  case FunctionDecl::TK_FunctionTemplateSpecialization:
+  case FunctionDecl::TK_FunctionTemplate:
+  case FunctionDecl::TK_DependentFunctionTemplateSpecialization:
+    break;
+  case FunctionDecl::TK_NonTemplate:
+  case FunctionDecl::TK_DependentNonTemplate:
+    return true;
+  }
+
+  StringRef Name = Decl->getName();
+  StringRef USR = API.recordUSR(Decl);
+  PresumedLoc Loc =
+      Context.getSourceManager().getPresumedLoc(Decl->getLocation());
+  DocComment Comment;
+  if (auto *RawComment =
+          getDerivedExtractAPIVisitor().fetchRawCommentForDecl(Decl))
+    Comment = RawComment->getFormattedLines(Context.getSourceManager(),
+                                            Context.getDiagnostics());
+  DeclarationFragments SubHeading =
+      DeclarationFragmentsBuilder::getSubHeading(Decl);
+
+  SmallString<128> ParentUSR;
+  index::generateUSRForDecl(dyn_cast<CXXRecordDecl>(Decl->getDeclContext()),
+                            ParentUSR);
+  if (Decl->isTemplated()) {
+    FunctionTemplateDecl *TemplateDecl = Decl->getDescribedFunctionTemplate();
+    API.addCXXMethodTemplate(
+        API.findRecordForUSR(ParentUSR), Name, USR, Loc, AvailabilitySet(Decl),
+        Comment,
+        DeclarationFragmentsBuilder::getFragmentsForFunctionTemplate(
+            TemplateDecl),
+        SubHeading, DeclarationFragmentsBuilder::getFunctionSignature(Decl),
+        DeclarationFragmentsBuilder::getAccessControl(TemplateDecl),
+        Template(TemplateDecl), isInSystemHeader(Decl));
+  } else if (Decl->getTemplateSpecializationInfo())
+    API.addCXXMethodTemplateSpec(
+        API.findRecordForUSR(ParentUSR), Name, USR, Loc, AvailabilitySet(Decl),
+        Comment,
+        DeclarationFragmentsBuilder::
+            getFragmentsForFunctionTemplateSpecialization(Decl),
+        SubHeading, DeclarationFragmentsBuilder::getFunctionSignature(Decl),
+        DeclarationFragmentsBuilder::getAccessControl(Decl),
+        isInSystemHeader(Decl));
+  return true;
+}
+
 template <typename Derived>
 bool ExtractAPIVisitorBase<Derived>::VisitConceptDecl(const ConceptDecl *Decl) {
   if (!getDerivedExtractAPIVisitor().shouldDeclBeIncluded(Decl))
@@ -712,6 +778,8 @@ bool ExtractAPIVisitorBase<Derived>::VisitVarTemplatePartialSpecializationDecl(
 template <typename Derived>
 bool ExtractAPIVisitorBase<Derived>::VisitFunctionTemplateDecl(
     const FunctionTemplateDecl *Decl) {
+  if (isa<CXXMethodDecl>(Decl->getTemplatedDecl()))
+    return true;
   if (!getDerivedExtractAPIVisitor().shouldDeclBeIncluded(Decl))
     return true;
 
@@ -1099,6 +1167,9 @@ void ExtractAPIVisitorBase<Derived>::recordCXXMethods(
       continue;
     }
 
+    if (Method->isFunctionTemplateSpecialization())
+      return;
+
     StringRef Name;
     DeclarationFragments Declaration;
     if (Method->isOverloadedOperator()) {

clang/include/clang/ExtractAPI/Serialization/SerializerBase.h

@@ -39,6 +39,10 @@ public:
 
     getDerived()->traverseClassTemplatePartialSpecializationRecords();
 
+    getDerived()->traverseCXXMethodTemplates();
+
+    getDerived()->traverseCXXMethodTemplateSpecializations();
+
     getDerived()->traverseConcepts();
 
     getDerived()->traverseGlobalVariableTemplateRecords();
@@ -94,6 +98,18 @@ public:
       getDerived()->visitCXXClassRecord(*Class.second);
   }
 
+  void traverseCXXMethodTemplates() {
+    for (const auto &MethodTemplate : API.getCXXMethodTemplates())
+      getDerived()->visitMethodTemplateRecord(*MethodTemplate.second);
+  }
+
+  void traverseCXXMethodTemplateSpecializations() {
+    for (const auto &MethodTemplateSpecialization :
+         API.getCXXMethodTemplateSpecializations())
+      getDerived()->visitMethodTemplateSpecializationRecord(
+          *MethodTemplateSpecialization.second);
+  }
+
   void traverseClassTemplateRecords() {
     for (const auto &ClassTemplate : API.getClassTemplates())
       getDerived()->visitClassTemplateRecord(*ClassTemplate.second);
@@ -200,6 +216,11 @@ public:
   void visitClassTemplatePartialSpecializationRecord(
       const ClassTemplatePartialSpecializationRecord &Record){};
 
+  void visitMethodTemplateRecord(const CXXMethodTemplateRecord &Record){};
+
+  void visitMethodTemplateSpecializationRecord(
+      const CXXMethodTemplateSpecializationRecord &Record){};
+
   void visitGlobalVariableTemplateRecord(
       const GlobalVariableTemplateRecord &Record) {}
 

clang/include/clang/ExtractAPI/Serialization/SymbolGraphSerializer.h

@@ -183,6 +183,11 @@ public:
   void visitClassTemplatePartialSpecializationRecord(
       const ClassTemplatePartialSpecializationRecord &Record);
 
+  void visitMethodTemplateRecord(const CXXMethodTemplateRecord &Record);
+
+  void visitMethodTemplateSpecializationRecord(
+      const CXXMethodTemplateSpecializationRecord &Record);
+
   void visitConceptRecord(const ConceptRecord &Record);
 
   void

clang/lib/ExtractAPI/API.cpp

@@ -311,6 +311,39 @@ CXXMethodRecord *APISet::addCXXSpecialMethod(
   return CXXClassRecord->Methods.emplace_back(std::move(Record)).get();
 }
 
+CXXMethodTemplateRecord *APISet::addCXXMethodTemplate(
+    APIRecord *Parent, StringRef Name, StringRef USR, PresumedLoc Loc,
+    AvailabilitySet Availability, const DocComment &Comment,
+    DeclarationFragments Declaration, DeclarationFragments SubHeading,
+    FunctionSignature Signature, AccessControl Access, Template Template,
+    bool IsFromSystemHeader) {
+  auto *Record = addTopLevelRecord(USRBasedLookupTable, CXXMethodTemplates, USR,
+                                   Name, Loc, std::move(Availability), Comment,
+                                   Declaration, SubHeading, Signature, Access,
+                                   Template, IsFromSystemHeader);
+  Record->ParentInformation = APIRecord::HierarchyInformation(
+      Parent->USR, Parent->Name, Parent->getKind(), Parent);
+
+  return Record;
+}
+
+CXXMethodTemplateSpecializationRecord *APISet::addCXXMethodTemplateSpec(
+    APIRecord *Parent, StringRef Name, StringRef USR, PresumedLoc Loc,
+    AvailabilitySet Availability, const DocComment &Comment,
+    DeclarationFragments Declaration, DeclarationFragments SubHeading,
+    FunctionSignature Signature, AccessControl Access,
+    bool IsFromSystemHeader) {
+
+  auto *Record = addTopLevelRecord(
+      USRBasedLookupTable, CXXMethodTemplateSpecializations, USR, Name, Loc,
+      std::move(Availability), Comment, Declaration, SubHeading, Signature,
+      Access, IsFromSystemHeader);
+  Record->ParentInformation = APIRecord::HierarchyInformation(
+      Parent->USR, Parent->Name, Parent->getKind(), Parent);
+
+  return Record;
+}
+
 ObjCCategoryRecord *APISet::addObjCCategory(
     StringRef Name, StringRef USR, PresumedLoc Loc,
     AvailabilitySet Availabilities, const DocComment &Comment,

clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp

@@ -420,6 +420,14 @@ Object serializeSymbolKind(APIRecord::RecordKind RK, Language Lang) {
     Kind["identifier"] = AddLangPrefix("class");
     Kind["displayName"] = "Class";
     break;
+  case APIRecord::RK_CXXMethodTemplate:
+    Kind["identifier"] = AddLangPrefix("method");
+    Kind["displayName"] = "Method Template";
+    break;
+  case APIRecord::RK_CXXMethodTemplateSpecialization:
+    Kind["identifier"] = AddLangPrefix("method");
+    Kind["displayName"] = "Method Template Specialization";
+    break;
   case APIRecord::RK_Concept:
     Kind["identifier"] = AddLangPrefix("concept");
     Kind["displayName"] = "Concept";
@@ -922,6 +930,32 @@ void SymbolGraphSerializer::visitClassTemplatePartialSpecializationRecord(
     serializeRelationship(RelationshipKind::InheritsFrom, Record, Base);
 }
 
+void SymbolGraphSerializer::visitMethodTemplateRecord(
+    const CXXMethodTemplateRecord &Record) {
+  if (!ShouldRecurse)
+    // Ignore child symbols
+    return;
+  auto MethodTemplate = serializeAPIRecord(Record);
+  if (!MethodTemplate)
+    return;
+  Symbols.emplace_back(std::move(*MethodTemplate));
+  serializeRelationship(RelationshipKind::MemberOf, Record,
+                        Record.ParentInformation.ParentRecord);
+}
+
+void SymbolGraphSerializer::visitMethodTemplateSpecializationRecord(
+    const CXXMethodTemplateSpecializationRecord &Record) {
+  if (!ShouldRecurse)
+    // Ignore child symbols
+    return;
+  auto MethodTemplateSpecialization = serializeAPIRecord(Record);
+  if (!MethodTemplateSpecialization)
+    return;
+  Symbols.emplace_back(std::move(*MethodTemplateSpecialization));
+  serializeRelationship(RelationshipKind::MemberOf, Record,
+                        Record.ParentInformation.ParentRecord);
+}
+
 void SymbolGraphSerializer::visitConceptRecord(const ConceptRecord &Record) {
   auto Concept = serializeAPIRecord(Record);
   if (!Concept)

clang/test/ExtractAPI/method_template.cpp

@@ -0,0 +1,244 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: sed -e "s@INPUT_DIR@%{/t:regex_replacement}@g" \
+// RUN: %t/reference.output.json.in >> %t/reference.output.json
+// RUN: %clang_cc1 -extract-api -triple arm64-apple-macosx \
+// RUN:   -x c++-header %t/input.h -o %t/output.json -verify
+
+// Generator version is not consistent across test runs, normalize it.
+// RUN: sed -e "s@\"generator\": \".*\"@\"generator\": \"?\"@g" \
+// RUN: %t/output.json >> %t/output-normalized.json
+// RUN: diff %t/reference.output.json %t/output-normalized.json
+
+//--- input.h
+class Foo {
+  template<typename T> void Bar(T Fizz);
+};
+
+/// expected-no-diagnostics
+
+//--- reference.output.json.in
+{
+  "metadata": {
+    "formatVersion": {
+      "major": 0,
+      "minor": 5,
+      "patch": 3
+    },
+    "generator": "?"
+  },
+  "module": {
+    "name": "",
+    "platform": {
+      "architecture": "arm64",
+      "operatingSystem": {
+        "minimumVersion": {
+          "major": 11,
+          "minor": 0,
+          "patch": 0
+        },
+        "name": "macosx"
+      },
+      "vendor": "apple"
+    }
+  },
+  "relationships": [
+    {
+      "kind": "memberOf",
+      "source": "c:@S@Foo@FT@>1#TBar#t0.0#v#",
+      "target": "c:@S@Foo",
+      "targetFallback": "Foo"
+    }
+  ],
+  "symbols": [
+    {
+      "accessLevel": "public",
+      "declarationFragments": [
+        {
+          "kind": "keyword",
+          "spelling": "class"
+        },
+        {
+          "kind": "text",
+          "spelling": " "
+        },
+        {
+          "kind": "identifier",
+          "spelling": "Foo"
+        },
+        {
+          "kind": "text",
+          "spelling": ";"
+        }
+      ],
+      "identifier": {
+        "interfaceLanguage": "c++",
+        "precise": "c:@S@Foo"
+      },
+      "kind": {
+        "displayName": "Class",
+        "identifier": "c++.class"
+      },
+      "location": {
+        "position": {
+          "character": 7,
+          "line": 1
+        },
+        "uri": "file://INPUT_DIR/input.h"
+      },
+      "names": {
+        "navigator": [
+          {
+            "kind": "identifier",
+            "spelling": "Foo"
+          }
+        ],
+        "subHeading": [
+          {
+            "kind": "identifier",
+            "spelling": "Foo"
+          }
+        ],
+        "title": "Foo"
+      },
+      "pathComponents": [
+        "Foo"
+      ]
+    },
+    {
+      "accessLevel": "private",
+      "declarationFragments": [
+        {
+          "kind": "keyword",
+          "spelling": "template"
+        },
+        {
+          "kind": "text",
+          "spelling": "<"
+        },
+        {
+          "kind": "keyword",
+          "spelling": "typename"
+        },
+        {
+          "kind": "text",
+          "spelling": " "
+        },
+        {
+          "kind": "genericParameter",
+          "spelling": "T"
+        },
+        {
+          "kind": "text",
+          "spelling": "> "
+        },
+        {
+          "kind": "typeIdentifier",
+          "preciseIdentifier": "c:v",
+          "spelling": "void"
+        },
+        {
+          "kind": "text",
+          "spelling": " "
+        },
+        {
+          "kind": "identifier",
+          "spelling": "Bar"
+        },
+        {
+          "kind": "text",
+          "spelling": "("
+        },
+        {
+          "kind": "typeIdentifier",
+          "preciseIdentifier": "c:t0.0",
+          "spelling": "T"
+        },
+        {
+          "kind": "text",
+          "spelling": " "
+        },
+        {
+          "kind": "internalParam",
+          "spelling": "Fizz"
+        },
+        {
+          "kind": "text",
+          "spelling": ");"
+        }
+      ],
+      "functionSignature": {
+        "parameters": [
+          {
+            "declarationFragments": [
+              {
+                "kind": "typeIdentifier",
+                "preciseIdentifier": "c:t0.0",
+                "spelling": "T"
+              },
+              {
+                "kind": "text",
+                "spelling": " "
+              },
+              {
+                "kind": "internalParam",
+                "spelling": "Fizz"
+              }
+            ],
+            "name": "Fizz"
+          }
+        ],
+        "returns": [
+          {
+            "kind": "typeIdentifier",
+            "preciseIdentifier": "c:v",
+            "spelling": "void"
+          }
+        ]
+      },
+      "identifier": {
+        "interfaceLanguage": "c++",
+        "precise": "c:@S@Foo@FT@>1#TBar#t0.0#v#"
+      },
+      "kind": {
+        "displayName": "Method Template",
+        "identifier": "c++.method"
+      },
+      "location": {
+        "position": {
+          "character": 29,
+          "line": 2
+        },
+        "uri": "file://INPUT_DIR/input.h"
+      },
+      "names": {
+        "navigator": [
+          {
+            "kind": "identifier",
+            "spelling": "Bar"
+          }
+        ],
+        "subHeading": [
+          {
+            "kind": "identifier",
+            "spelling": "Bar"
+          }
+        ],
+        "title": "Bar"
+      },
+      "pathComponents": [
+        "Foo",
+        "Bar"
+      ],
+      "swiftGenerics": {
+        "parameters": [
+          {
+            "depth": 0,
+            "index": 0,
+            "name": "T"
+          }
+        ]
+      }
+    }
+  ]
+}

clang/test/ExtractAPI/method_template_spec.cpp

@@ -0,0 +1,371 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: sed -e "s@INPUT_DIR@%{/t:regex_replacement}@g" \
+// RUN: %t/reference.output.json.in >> %t/reference.output.json
+// RUN: %clang_cc1 -extract-api -triple arm64-apple-macosx \
+// RUN:   -x c++-header %t/input.h -o %t/output.json -verify
+
+// Generator version is not consistent across test runs, normalize it.
+// RUN: sed -e "s@\"generator\": \".*\"@\"generator\": \"?\"@g" \
+// RUN: %t/output.json >> %t/output-normalized.json
+// RUN: diff %t/reference.output.json %t/output-normalized.json
+
+//--- input.h
+class Foo {
+  template<typename T> void Bar(T Fizz);
+
+  template<> void Bar<int>(int Fizz);
+};
+
+/// expected-no-diagnostics
+
+//--- reference.output.json.in
+{
+  "metadata": {
+    "formatVersion": {
+      "major": 0,
+      "minor": 5,
+      "patch": 3
+    },
+    "generator": "?"
+  },
+  "module": {
+    "name": "",
+    "platform": {
+      "architecture": "arm64",
+      "operatingSystem": {
+        "minimumVersion": {
+          "major": 11,
+          "minor": 0,
+          "patch": 0
+        },
+        "name": "macosx"
+      },
+      "vendor": "apple"
+    }
+  },
+  "relationships": [
+    {
+      "kind": "memberOf",
+      "source": "c:@S@Foo@FT@>1#TBar#t0.0#v#",
+      "target": "c:@S@Foo",
+      "targetFallback": "Foo"
+    },
+    {
+      "kind": "memberOf",
+      "source": "c:@S@Foo@F@Bar<#I>#I#",
+      "target": "c:@S@Foo",
+      "targetFallback": "Foo"
+    }
+  ],
+  "symbols": [
+    {
+      "accessLevel": "public",
+      "declarationFragments": [
+        {
+          "kind": "keyword",
+          "spelling": "class"
+        },
+        {
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