When certain diagnostics involving run-time behavior would be emitted
in a potentially potentially evaluated context, queue those
diagnostics and only emit them if the context ends up being
potentially evaluated. This completes the fix for PR5761.

llvm-svn: 91213
diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index baf9c23..ada8aa1 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -339,6 +339,10 @@
   typedef std::vector<std::pair<SourceLocation, Decl *> > 
     PotentiallyReferencedDecls;
 
+  /// \brief A set of diagnostics that may be emitted.
+  typedef std::vector<std::pair<SourceLocation, PartialDiagnostic> >
+    PotentiallyEmittedDiagnostics;
+
   /// \brief Data structure used to record current or nested
   /// expression evaluation contexts.
   struct ExpressionEvaluationContextRecord {
@@ -358,10 +362,14 @@
     /// evaluated.
     PotentiallyReferencedDecls *PotentiallyReferenced;
 
+    /// \brief The set of diagnostics to emit should this potentially
+    /// potentially-evaluated context become evaluated.
+    PotentiallyEmittedDiagnostics *PotentiallyDiagnosed;
+
     ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
                                       unsigned NumTemporaries) 
       : Context(Context), NumTemporaries(NumTemporaries), 
-        PotentiallyReferenced(0) { }
+        PotentiallyReferenced(0), PotentiallyDiagnosed(0) { }
 
     void addReferencedDecl(SourceLocation Loc, Decl *Decl) {
       if (!PotentiallyReferenced)
@@ -369,9 +377,17 @@
       PotentiallyReferenced->push_back(std::make_pair(Loc, Decl));
     }
 
+    void addDiagnostic(SourceLocation Loc, const PartialDiagnostic &PD) {
+      if (!PotentiallyDiagnosed)
+        PotentiallyDiagnosed = new PotentiallyEmittedDiagnostics;
+      PotentiallyDiagnosed->push_back(std::make_pair(Loc, PD));
+    }
+
     void Destroy() {
       delete PotentiallyReferenced;
+      delete PotentiallyDiagnosed;
       PotentiallyReferenced = 0;
+      PotentiallyDiagnosed = 0;
     }
   };
 
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 1ca47a4..7cdc275 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -271,7 +271,9 @@
       return true;
 
     case PotentiallyPotentiallyEvaluated:
-      // FIXME: queue it!
+      ExprEvalContexts.back().addDiagnostic(Expr->getLocStart(),
+                           PDiag(diag::err_cannot_pass_objc_interface_to_vararg) 
+                             << Expr->getType() << CT);
       break;
     }
   }
@@ -288,7 +290,9 @@
       break;
 
     case PotentiallyPotentiallyEvaluated:
-      // FIXME: queue it!
+      ExprEvalContexts.back().addDiagnostic(Expr->getLocStart(),
+                           PDiag(diag::warn_cannot_pass_non_pod_arg_to_vararg) 
+                             << Expr->getType() << CT);
       break;
     }
   }
@@ -6488,7 +6492,10 @@
             break;
             
           case PotentiallyPotentiallyEvaluated:
-            // FIXME: Queue it!
+            ExprEvalContexts.back().addDiagnostic(BuiltinLoc,
+                              PDiag(diag::warn_offsetof_non_pod_type)
+                                << SourceRange(CompPtr[0].LocStart, OC.LocEnd)
+                                << Res->getType());
             DidWarnAboutNonPOD = true;
             break;
           }
@@ -6957,16 +6964,26 @@
   ExpressionEvaluationContextRecord Rec = ExprEvalContexts.back();
   ExprEvalContexts.pop_back();
 
-  if (Rec.Context == PotentiallyPotentiallyEvaluated && 
-      Rec.PotentiallyReferenced) {
-    // Mark any remaining declarations in the current position of the stack
-    // as "referenced". If they were not meant to be referenced, semantic
-    // analysis would have eliminated them (e.g., in ActOnCXXTypeId).
-    for (PotentiallyReferencedDecls::iterator 
-              I = Rec.PotentiallyReferenced->begin(),
-           IEnd = Rec.PotentiallyReferenced->end();
-         I != IEnd; ++I)
-      MarkDeclarationReferenced(I->first, I->second);
+  if (Rec.Context == PotentiallyPotentiallyEvaluated) {
+    if (Rec.PotentiallyReferenced) {
+      // Mark any remaining declarations in the current position of the stack
+      // as "referenced". If they were not meant to be referenced, semantic
+      // analysis would have eliminated them (e.g., in ActOnCXXTypeId).
+      for (PotentiallyReferencedDecls::iterator 
+             I = Rec.PotentiallyReferenced->begin(),
+             IEnd = Rec.PotentiallyReferenced->end();
+           I != IEnd; ++I)
+        MarkDeclarationReferenced(I->first, I->second);
+    }
+
+    if (Rec.PotentiallyDiagnosed) {
+      // Emit any pending diagnostics.
+      for (PotentiallyEmittedDiagnostics::iterator
+                I = Rec.PotentiallyDiagnosed->begin(),
+             IEnd = Rec.PotentiallyDiagnosed->end();
+           I != IEnd; ++I)
+        Diag(I->first, I->second);
+    }
   } 
 
   // When are coming out of an unevaluated context, clear out any