[cfe-commits] r146265 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaDeclCXX.cpp test/SemaCXX/warn-weak-vtables.cpp

David Blaikie dblaikie at gmail.com
Fri Dec 9 12:32:51 CST 2011


Author: dblaikie
Date: Fri Dec  9 12:32:50 2011
New Revision: 146265

URL: http://llvm.org/viewvc/llvm-project?rev=146265&view=rev
Log:
Provide a separate warning for weak vtables in explicit template instantiations. There's no (current) way to fix such templates to emit strong symbols/vtables, but perhaps users want to know about the cost being incurred anyway.

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaDeclCXX.cpp
    cfe/trunk/test/SemaCXX/warn-weak-vtables.cpp

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=146265&r1=146264&r2=146265&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Dec  9 12:32:50 2011
@@ -701,6 +701,10 @@
   "%0 has no out-of-line virtual method definitions; its vtable will be "
   "emitted in every translation unit">,
   InGroup<DiagGroup<"weak-vtables">>, DefaultIgnore;
+def warn_weak_template_vtable : Warning<
+  "explicit template instantiation %0 will emit a vtable in every "
+  "translation unit">,
+  InGroup<DiagGroup<"weak-template-vtables">>, DefaultIgnore;
 
 def ext_using_undefined_std : ExtWarn<
   "using directive refers to implicitly-defined namespace 'std'">;

Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=146265&r1=146264&r2=146265&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Fri Dec  9 12:32:50 2011
@@ -10617,7 +10617,10 @@
       if (!KeyFunction || 
           (KeyFunction->hasBody(KeyFunctionDef) && 
            KeyFunctionDef->isInlined()))
-        Diag(Class->getLocation(), diag::warn_weak_vtable) << Class;
+        Diag(Class->getLocation(), Class->getTemplateSpecializationKind() ==
+             TSK_ExplicitInstantiationDefinition 
+             ? diag::warn_weak_template_vtable : diag::warn_weak_vtable) 
+          << Class;
     }
   }
   VTableUses.clear();

Modified: cfe/trunk/test/SemaCXX/warn-weak-vtables.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-weak-vtables.cpp?rev=146265&r1=146264&r2=146265&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/warn-weak-vtables.cpp (original)
+++ cfe/trunk/test/SemaCXX/warn-weak-vtables.cpp Fri Dec  9 12:32:50 2011
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -fsyntax-only -verify -Wweak-vtables
+// RUN: %clang_cc1 %s -fsyntax-only -verify -Wweak-vtables -Wweak-template-vtables
 
 struct A { // expected-warning {{'A' has no out-of-line virtual method definitions; its vtable will be emitted in every translation unit}}
   virtual void f() { } 
@@ -56,3 +56,23 @@
   d.getFoo();
   vd.getFoo();
 }
+
+template<typename T> struct TemplVirt {
+  virtual void f();
+};
+
+template class TemplVirt<float>; // expected-warning{{explicit template instantiation 'TemplVirt<float>' will emit a vtable in every translation unit}}
+
+template<> struct TemplVirt<bool> {
+  virtual void f();
+};
+
+template<> struct TemplVirt<long> { // expected-warning{{'TemplVirt<long>' has no out-of-line virtual method definitions; its vtable will be emitted in every translation unit}}
+  virtual void f() {}
+};
+
+void uses(TemplVirt<float>& f, TemplVirt<bool>& b, TemplVirt<long>& l) {
+  f.f();
+  b.f();
+  l.f();
+}




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