Generate error on declaration containing 'static' and '__attribute__((weak))'
Patch by Ryan Flynn


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@75879 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index f552a2f..9b9f96e 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -488,6 +488,8 @@
   "__weak attribute cannot be specified on a field declaration">;
 def warn_attribute_weak_on_local : Warning<
   "__weak attribute cannot be specified on an automatic variable">;
+def err_attribute_weak_static : Error<
+  "weak declaration of '%0' must be public">;
 def warn_attribute_weak_import_invalid_on_definition : Warning<
   "'weak_import' attribute cannot be specified on a definition">;
 def warn_attribute_wrong_decl_type : Warning<
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index f5babc1..09cb96b 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -796,6 +796,19 @@
     return;
   }
 
+  /* weak only applies to non-static declarations */
+  bool isStatic = false;
+  if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
+    isStatic = VD->getStorageClass() == VarDecl::Static;
+  } else if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+    isStatic = FD->getStorageClass() == FunctionDecl::Static;
+  }
+  if (isStatic) {
+    S.Diag(Attr.getLoc(), diag::err_attribute_weak_static) <<
+      dyn_cast<NamedDecl>(D)->getNameAsString();
+    return;
+  }
+
   // TODO: could also be applied to methods?
   if (!isa<FunctionDecl>(D) && !isa<VarDecl>(D)) {
     S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
diff --git a/test/Sema/attr-weak.c b/test/Sema/attr-weak.c
index b79e1e7..4e28867 100644
--- a/test/Sema/attr-weak.c
+++ b/test/Sema/attr-weak.c
@@ -11,3 +11,5 @@
 struct __attribute__((weak)) s0 {}; // expected-warning {{'weak' attribute only applies to variable and function types}}
 struct __attribute__((weak_import)) s1 {}; // expected-warning {{'weak_import' attribute only applies to variable and function types}}
 
+static int x __attribute__((weak)); // expected-error {{weak declaration of 'x' must be public}}
+