commit 623ef4bf31bc5ec14ed9b5645921a0a2e0d00ee4
author Richard Smith <richard-llvm@metafoo.co.uk> Sun Oct 28 04:47:21 2012 +0000
committer Richard Smith <richard-llvm@metafoo.co.uk> Sun Oct 28 04:47:21 2012 +0000
tree 3b244223410f71719b0a3f784ac8844aba4589c7
parent 644e90a17f1bc3dcc2b7b018eb02abb3a1c2022b

In -Wunneeded-internal-declaration, suppress the warning for variables which
might have been used in constant expressions, rather than suppressing it for
variables which are const. The important thing here is that such variables
can have their values used without actually being marked as 'used'.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@166896 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaDecl.cpp

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index e8d017c..3576190 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1205,10 +1205,17 @@
       return false;
   } else if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
     if (!VD->isFileVarDecl() ||
-        VD->getType().isConstant(Context) ||
         Context.DeclMustBeEmitted(VD))
       return false;
 
+    // If a variable is usable in constant expressions and it's not odr-used,
+    // its value may still have been used. Conservatively suppress the warning
+    // in this case.
+    const VarDecl *VDWithInit = 0;
+    if (VD->isUsableInConstantExpressions(Context) &&
+        VD->getAnyInitializer(VDWithInit) && VDWithInit->checkInitIsICE())
+      return false;
+
     if (VD->isStaticDataMember() &&
         VD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
       return false;

test/SemaCXX/warn-unused-filescoped.cpp

diff --git a/test/SemaCXX/warn-unused-filescoped.cpp b/test/SemaCXX/warn-unused-filescoped.cpp
index dbff4b0..328d8bb 100644
--- a/test/SemaCXX/warn-unused-filescoped.cpp
+++ b/test/SemaCXX/warn-unused-filescoped.cpp
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -std=c++98 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wunused -Wunused-member-function -std=c++11 %s
 
 static void f1(); // expected-warning{{unused}}
 
@@ -87,3 +88,15 @@
     foo();
   }
 }
+
+namespace test5 {
+  static int n = 0;
+  static int &r = n;
+  int f(int &);
+  int k = f(r);
+
+  static const int m = n; // expected-warning {{not needed and will not be emitted}}
+  int x = sizeof(m);
+  static const double d = 0.0; // expected-warning {{not needed and will not be emitted}}
+  int y = sizeof(d);
+}