Reword warning about using a *static* variable within its own initialization.

The warning is still under -Wuninitialized (although technically this
is defined behavior), but under a subgroup -Wstatic-self-init.

This addresses PR 10265.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172878 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 16 insertions, 5 deletions

diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index 24c4ef3b40..8a2d596586 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -259,7 +259,9 @@ def UndefinedReinterpretCast : DiagGroup<"undefined-reinterpret-cast">;
 def Unicode  : DiagGroup<"unicode">;
 def UninitializedMaybe : DiagGroup<"conditional-uninitialized">;
 def UninitializedSometimes : DiagGroup<"sometimes-uninitialized">;
-def Uninitialized  : DiagGroup<"uninitialized", [UninitializedSometimes]>;
+def UninitializedStaticSelfInit : DiagGroup<"static-self-init">;
+def Uninitialized  : DiagGroup<"uninitialized", [UninitializedSometimes,
+                                                 UninitializedStaticSelfInit]>;
 def UnknownPragmas : DiagGroup<"unknown-pragmas">;
 def UnknownWarningOption : DiagGroup<"unknown-warning-option">;
 def NSobjectAttribute : DiagGroup<"NSObject-attribute">;
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index c23d9eee48..c3f034a53a 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1292,6 +1292,9 @@ def warn_field_is_uninit : Warning<"field %0 is uninitialized when used here">,
 def warn_reference_field_is_uninit : Warning<
   "reference %0 is not yet bound to a value when used here">,
   InGroup<Uninitialized>;
+def warn_static_self_reference_in_init : Warning<
+  "static variable %0 is suspiciously used within its own initialization">,
+  InGroup<UninitializedStaticSelfInit>;
 def warn_uninit_self_reference_in_init : Warning<
   "variable %0 is uninitialized when used within its own initialization">,
   InGroup<Uninitialized>;
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 9cf5e73665..dbdbc3d6a2 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -6683,11 +6683,17 @@ namespace {
     void VisitObjCMessageExpr(ObjCMessageExpr *E) { return; }
 
     void HandleDeclRefExpr(DeclRefExpr *DRE) {
-      Decl* ReferenceDecl = DRE->getDecl(); 
+      Decl* ReferenceDecl = DRE->getDecl();
       if (OrigDecl != ReferenceDecl) return;
-      unsigned diag = isReferenceType
-          ? diag::warn_uninit_self_reference_in_reference_init
-          : diag::warn_uninit_self_reference_in_init;
+      unsigned diag;
+      if (isReferenceType) {
+        diag = diag::warn_uninit_self_reference_in_reference_init;
+      } else if (cast<VarDecl>(OrigDecl)->isStaticLocal()) {
+        diag = diag::warn_static_self_reference_in_init;
+      } else {
+        diag = diag::warn_uninit_self_reference_in_init;
+      }
+
       S.DiagRuntimeBehavior(DRE->getLocStart(), DRE,
                             S.PDiag(diag)
                               << DRE->getNameInfo().getName()