From 80cb549c2fb973ffa84276b6144e0aa65ef690c9 Mon Sep 17 00:00:00 2001
From: Alex Lorenz <arphaman@gmail.com>
Date: Mon, 22 May 2017 16:50:54 +0000
Subject: [PATCH] [index] Index the default template parameter values

rdar://32323724

llvm-svn: 303568
---
 clang/lib/Index/IndexDecl.cpp          | 46 ++++++++++++++++++++++++++
 clang/test/Index/Core/index-source.cpp | 59 ++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)

diff --git a/clang/lib/Index/IndexDecl.cpp b/clang/lib/Index/IndexDecl.cpp
index 7f940ef..870b4e4 100644
--- a/clang/lib/Index/IndexDecl.cpp
+++ b/clang/lib/Index/IndexDecl.cpp
@@ -63,6 +63,17 @@ public:
     case TemplateArgument::Type:
       IndexCtx.indexTypeSourceInfo(LocInfo.getAsTypeSourceInfo(), Parent, DC);
       break;
+    case TemplateArgument::Template:
+    case TemplateArgument::TemplateExpansion:
+      IndexCtx.indexNestedNameSpecifierLoc(TALoc.getTemplateQualifierLoc(),
+                                           Parent, DC);
+      if (const TemplateDecl *TD = TALoc.getArgument()
+                                       .getAsTemplateOrTemplatePattern()
+                                       .getAsTemplateDecl()) {
+        if (const NamedDecl *TTD = TD->getTemplatedDecl())
+          IndexCtx.handleReference(TTD, TALoc.getTemplateNameLoc(), Parent, DC);
+      }
+      break;
     default:
       break;
     }
@@ -610,8 +621,43 @@ public:
     return true;
   }
 
+  static bool shouldIndexTemplateParameterDefaultValue(const NamedDecl *D) {
+    if (!D)
+      return false;
+    // We want to index the template parameters only once when indexing the
+    // canonical declaration.
+    if (const auto *FD = dyn_cast<FunctionDecl>(D))
+      return FD->getCanonicalDecl() == FD;
+    else if (const auto *TD = dyn_cast<TagDecl>(D))
+      return TD->getCanonicalDecl() == TD;
+    else if (const auto *VD = dyn_cast<VarDecl>(D))
+      return VD->getCanonicalDecl() == VD;
+    return true;
+  }
+
   bool VisitTemplateDecl(const TemplateDecl *D) {
     // FIXME: Template parameters.
+
+    // Index the default values for the template parameters.
+    const NamedDecl *Parent = D->getTemplatedDecl();
+    if (D->getTemplateParameters() &&
+        shouldIndexTemplateParameterDefaultValue(Parent)) {
+      const TemplateParameterList *Params = D->getTemplateParameters();
+      for (const NamedDecl *TP : *Params) {
+        if (const auto *TTP = dyn_cast<TemplateTypeParmDecl>(TP)) {
+          if (TTP->hasDefaultArgument())
+            IndexCtx.indexTypeSourceInfo(TTP->getDefaultArgumentInfo(), Parent);
+        } else if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(TP)) {
+          if (NTTP->hasDefaultArgument())
+            IndexCtx.indexBody(NTTP->getDefaultArgument(), Parent);
+        } else if (const auto *TTPD = dyn_cast<TemplateTemplateParmDecl>(TP)) {
+          if (TTPD->hasDefaultArgument())
+            handleTemplateArgumentLoc(TTPD->getDefaultArgument(), Parent,
+                                      /*DC=*/nullptr);
+        }
+      }
+    }
+
     return Visit(D->getTemplatedDecl());
   }
 
diff --git a/clang/test/Index/Core/index-source.cpp b/clang/test/Index/Core/index-source.cpp
index e5f58d1..8b04931 100644
--- a/clang/test/Index/Core/index-source.cpp
+++ b/clang/test/Index/Core/index-source.cpp
@@ -374,3 +374,62 @@ struct DeletedMethods {
 // CHECK: [[@LINE-3]]:24 | struct/C++ | DeletedMethods | c:@S@DeletedMethods | <no-cgname> | Ref,RelCont | rel: 1
 // CHECK: [[@LINE-4]]:3 | struct/C++ | DeletedMethods | c:@S@DeletedMethods | <no-cgname> | Ref,RelCont | rel: 1
 };
+
+namespace ns2 {
+template<typename T> struct ACollectionDecl { };
+}
+
+template<typename T = Cls,
+// CHECK: [[@LINE-1]]:23 | class/C++ | Cls | c:@S@Cls | <no-cgname> | Ref,RelCont | rel: 1
+// CHECK-NEXT: RelCont | TemplateDefaultValues | c:@ST>3#T#NI#t>1#T@TemplateDefaultValues
+         int x = Record::C,
+// CHECK: [[@LINE-1]]:26 | static-property/C++ | C | c:@S@Record@C | __ZN6Record1CE | Ref,Read,RelCont | rel: 1
+// CHECK-NEXT: RelCont | TemplateDefaultValues | c:@ST>3#T#NI#t>1#T@TemplateDefaultValues
+// CHECK: [[@LINE-3]]:18 | struct/C++ | Record | c:@S@Record | <no-cgname> | Ref,RelCont | rel: 1
+         template <typename> class Collection = ns2::ACollectionDecl>
+// CHECK: [[@LINE-1]]:49 | namespace/C++ | ns2 | c:@N@ns2 | <no-cgname> | Ref,RelCont | rel: 1
+// CHECK-NEXT: RelCont | TemplateDefaultValues | c:@ST>3#T#NI#t>1#T@TemplateDefaultValues
+// CHECK: [[@LINE-3]]:54 | struct(Gen)/C++ | ACollectionDecl | c:@N@ns2@ST>1#T@ACollectionDecl | <no-cgname> | Ref,RelCont | rel: 1
+// CHECK-NEXT: RelCont | TemplateDefaultValues | c:@ST>3#T#NI#t>1#T@TemplateDefaultValues
+struct TemplateDefaultValues { };
+
+template<typename T = Record,
+// CHECK: [[@LINE-1]]:23 | struct/C++ | Record | c:@S@Record | <no-cgname> | Ref,RelCont | rel: 1
+         int x = sizeof(Cls)>
+// CHECK: [[@LINE-1]]:25 | class/C++ | Cls | c:@S@Cls | <no-cgname> | Ref,RelCont | rel: 1
+void functionTemplateDefaultValues() { }
+
+namespace ensureDefaultTemplateParamsAreRecordedOnce {
+
+template<typename T = Cls>
+// CHECK: [[@LINE-1]]:23 | class/C++ | Cls | c:@S@Cls | <no-cgname> | Ref,RelCont | rel: 1
+// CHECK-NOT: [[@LINE-2]]:23
+void functionDecl();
+
+template<typename T>
+void functionDecl() { }
+
+template<typename T = Cls>
+// CHECK: [[@LINE-1]]:23 | class/C++ | Cls | c:@S@Cls | <no-cgname> | Ref,RelCont | rel: 1
+// CHECK-NOT: [[@LINE-2]]:23
+class TagDecl;
+
+template<typename T>
+class TagDecl;
+
+template<typename T>
+class TagDecl { };
+
+template<typename T = Cls>
+// CHECK: [[@LINE-1]]:23 | class/C++ | Cls | c:@S@Cls | <no-cgname> | Ref,RelCont | rel: 1
+using TypeAlias = TagDecl<T>;
+
+template<typename T = Cls>
+// CHECK: [[@LINE-1]]:23 | class/C++ | Cls | c:@S@Cls | <no-cgname> | Ref,RelCont | rel: 1
+// CHECK-NOT: [[@LINE-2]]:23
+extern T varDecl;
+
+template<typename T>
+T varDecl = T();
+
+} // end namespace ensureDefaultTemplateParamsAreRecordedOnce
-- 
2.7.4