[SemaCXX] Add diagnostics to require_constant_initialization

Summary:
This hooks up the detailed diagnostics of why constant initialization was
not possible if require_constant_initialization reports an error.
I have updated the test to account for the new notes.

Reviewed By: EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D24371

llvm-svn: 304451

1 files changed, 11 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index a9adbec4f84..ea1f7526a83 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -11116,6 +11116,17 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
           << Init->getSourceRange();
         Diag(attr->getLocation(), diag::note_declared_required_constant_init_here)
           << attr->getRange();
+        if (getLangOpts().CPlusPlus11) {
+          APValue Value;
+          SmallVector<PartialDiagnosticAt, 8> Notes;
+          Init->EvaluateAsInitializer(Value, getASTContext(), var, Notes);
+          for (auto &it : Notes)
+            Diag(it.first, it.second);
+        } else {
+          Diag(CacheCulprit->getExprLoc(),
+               diag::note_invalid_subexpr_in_const_expr)
+              << CacheCulprit->getSourceRange();
+        }
       }
     }
     else if (!var->isConstexpr() && IsGlobal &&