[index] The relation between the declarations in template specializations

that 'override' declarations in the base template should be recorded

This can be used for improved "go to definition" feature in Xcode.

rdar://31604739

Differential Revision: https://reviews.llvm.org/D32020

llvm-svn: 301180

1 files changed, 60 insertions, 4 deletions

diff --git a/clang/lib/Index/IndexDecl.cpp b/clang/lib/Index/IndexDecl.cpp
index 8028f8892f0..ba65889a6f9 100644
--- a/clang/lib/Index/IndexDecl.cpp
+++ b/clang/lib/Index/IndexDecl.cpp
@@ -144,6 +144,53 @@ public:
     return true;
   }
 
+  /// Gather the declarations which the given declaration \D overrides in a
+  /// pseudo-override manner.
+  ///
+  /// Pseudo-overrides occur when a class template specialization declares
+  /// a declaration that has the same name as a similar declaration in the
+  /// non-specialized template.
+  void
+  gatherTemplatePseudoOverrides(const NamedDecl *D,
+                                SmallVectorImpl<SymbolRelation> &Relations) {
+    if (!IndexCtx.getLangOpts().CPlusPlus)
+      return;
+    const auto *CTSD =
+        dyn_cast<ClassTemplateSpecializationDecl>(D->getLexicalDeclContext());
+    if (!CTSD)
+      return;
+    llvm::PointerUnion<ClassTemplateDecl *,
+                       ClassTemplatePartialSpecializationDecl *>
+        Template = CTSD->getSpecializedTemplateOrPartial();
+    if (const auto *CTD = Template.dyn_cast<ClassTemplateDecl *>()) {
+      const CXXRecordDecl *Pattern = CTD->getTemplatedDecl();
+      bool TypeOverride = isa<TypeDecl>(D);
+      for (const NamedDecl *ND : Pattern->lookup(D->getDeclName())) {
+        if (const auto *CTD = dyn_cast<ClassTemplateDecl>(ND))
+          ND = CTD->getTemplatedDecl();
+        if (ND->isImplicit())
+          continue;
+        // Types can override other types.
+        if (!TypeOverride) {
+          if (ND->getKind() != D->getKind())
+            continue;
+        } else if (!isa<TypeDecl>(ND))
+          continue;
+        if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
+          const auto *DFD = cast<FunctionDecl>(D);
+          // Function overrides are approximated using the number of parameters.
+          if (FD->getStorageClass() != DFD->getStorageClass() ||
+              FD->getNumParams() != DFD->getNumParams())
+            continue;
+        }
+        Relations.emplace_back(
+            SymbolRoleSet(SymbolRole::RelationOverrideOf) |
+                SymbolRoleSet(SymbolRole::RelationSpecializationOf),
+            ND);
+      }
+    }
+  }
+
   bool VisitFunctionDecl(const FunctionDecl *D) {
     if (D->isDeleted())
       return true;
@@ -158,6 +205,7 @@ public:
         Relations.emplace_back((unsigned)SymbolRole::RelationOverrideOf, *I);
       }
     }
+    gatherTemplatePseudoOverrides(D, Relations);
 
     TRY_DECL(D, IndexCtx.handleDecl(D, Roles, Relations));
     handleDeclarator(D);
@@ -194,14 +242,18 @@ public:
   }
 
   bool VisitVarDecl(const VarDecl *D) {
-    TRY_DECL(D, IndexCtx.handleDecl(D));
+    SmallVector<SymbolRelation, 4> Relations;
+    gatherTemplatePseudoOverrides(D, Relations);
+    TRY_DECL(D, IndexCtx.handleDecl(D, SymbolRoleSet(), Relations));
     handleDeclarator(D);
     IndexCtx.indexBody(D->getInit(), D);
     return true;
   }
 
   bool VisitFieldDecl(const FieldDecl *D) {
-    TRY_DECL(D, IndexCtx.handleDecl(D));
+    SmallVector<SymbolRelation, 4> Relations;
+    gatherTemplatePseudoOverrides(D, Relations);
+    TRY_DECL(D, IndexCtx.handleDecl(D, SymbolRoleSet(), Relations));
     handleDeclarator(D);
     if (D->isBitField())
       IndexCtx.indexBody(D->getBitWidth(), D);
@@ -233,7 +285,9 @@ public:
 
   bool VisitTypedefNameDecl(const TypedefNameDecl *D) {
     if (!D->isTransparentTag()) {
-      TRY_DECL(D, IndexCtx.handleDecl(D));
+      SmallVector<SymbolRelation, 4> Relations;
+      gatherTemplatePseudoOverrides(D, Relations);
+      TRY_DECL(D, IndexCtx.handleDecl(D, SymbolRoleSet(), Relations));
       IndexCtx.indexTypeSourceInfo(D->getTypeSourceInfo(), D);
     }
     return true;
@@ -243,7 +297,9 @@ public:
     // Non-free standing tags are handled in indexTypeSourceInfo.
     if (D->isFreeStanding()) {
       if (D->isThisDeclarationADefinition()) {
-        IndexCtx.indexTagDecl(D);
+        SmallVector<SymbolRelation, 4> Relations;
+        gatherTemplatePseudoOverrides(D, Relations);
+        IndexCtx.indexTagDecl(D, Relations);
       } else {
         auto *Parent = dyn_cast<NamedDecl>(D->getDeclContext());
         return IndexCtx.handleReference(D, D->getLocation(), Parent,