Warn about unused static file scope function template declarations.

Reviewed by Richard Smith (D29877)!

llvm-svn: 299930

2 files changed, 18 insertions, 5 deletions

diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index 294b56059b3..f943ab56507 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -470,6 +470,13 @@ static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
     return true;
 
   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+    // If this is a function template and none of its specializations is used,
+    // we should warn.
+    if (FunctionTemplateDecl *Template = FD->getDescribedFunctionTemplate())
+      for (const auto *Spec : Template->specializations())
+        if (ShouldRemoveFromUnused(SemaRef, Spec))
+          return true;
+
     // UnusedFileScopedDecls stores the first declaration.
     // The declaration may have become definition so check again.
     const FunctionDecl *DeclToCheck;
@@ -493,6 +500,13 @@ static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) {
         VD->isUsableInConstantExpressions(SemaRef->Context))
       return true;
 
+    if (VarTemplateDecl *Template = VD->getDescribedVarTemplate())
+      // If this is a variable template and none of its specializations is used,
+      // we should warn.
+      for (const auto *Spec : Template->specializations())
+        if (ShouldRemoveFromUnused(SemaRef, Spec))
+          return true;
+
     // UnusedFileScopedDecls stores the first declaration.
     // The declaration may have become definition so check again.
     const VarDecl *DeclToCheck = VD->getDefinition();
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 02cbca8b2bb..20d1e0c6da6 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -8887,6 +8887,7 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
     if (FunctionTemplate) {
       if (NewFD->isInvalidDecl())
         FunctionTemplate->setInvalidDecl();
+      MarkUnusedFileScopedDecl(NewFD);
       return FunctionTemplate;
     }
   }
@@ -10987,8 +10988,7 @@ static bool hasDependentAlignment(VarDecl *VD) {
 
 /// FinalizeDeclaration - called by ParseDeclarationAfterDeclarator to perform
 /// any semantic actions necessary after any initializer has been attached.
-void
-Sema::FinalizeDeclaration(Decl *ThisDecl) {
+void Sema::FinalizeDeclaration(Decl *ThisDecl) {
   // Note that we are no longer parsing the initializer for this declaration.
   ParsingInitForAutoVars.erase(ThisDecl);
 
@@ -11153,9 +11153,8 @@ Sema::FinalizeDeclaration(Decl *ThisDecl) {
   if (DC->getRedeclContext()->isFileContext() && VD->isExternallyVisible())
     AddPushedVisibilityAttribute(VD);
 
-  // FIXME: Warn on unused templates.
-  if (VD->isFileVarDecl() && !VD->getDescribedVarTemplate() &&
-      !isa<VarTemplatePartialSpecializationDecl>(VD))
+  // FIXME: Warn on unused var template partial specializations.
+  if (VD->isFileVarDecl() && !isa<VarTemplatePartialSpecializationDecl>(VD))
     MarkUnusedFileScopedDecl(VD);
 
   // Now we have parsed the initializer and can update the table of magic