Implement the part of C89 6.5.7 p3 requiring a constant initializer list

when initializing aggregate/union types, no matter if static or not.

llvm-svn: 186817

3 files changed, 19 insertions, 3 deletions

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 1ca349920e8..8e88f3d0dd1 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3626,6 +3626,8 @@ def warn_typecheck_zero_static_array_size : Warning<
 def err_array_size_non_int : Error<"size of array has non-integer type %0">;
 def err_init_element_not_constant : Error<
   "initializer element is not a compile-time constant">;
+def ext_aggregate_init_not_constant : Extension<
+  "initializer for aggregate is not a compile-time constant">, InGroup<C99>;
 def err_local_cant_init : Error<
   "'__local' variable cannot have an initializer">;
 def err_block_extern_cant_init : Error<
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index aeae35aba97..840a735e1b5 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -7777,9 +7777,19 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init,
     // C99 6.7.8p4: All the expressions in an initializer for an object that has
     // static storage duration shall be constant expressions or string literals.
     // C++ does not have this restriction.
-    if (!getLangOpts().CPlusPlus && !VDecl->isInvalidDecl() &&
-        VDecl->getStorageClass() == SC_Static)
-      CheckForConstantInitializer(Init, DclT);
+    if (!getLangOpts().CPlusPlus && !VDecl->isInvalidDecl()) {
+      if (VDecl->getStorageClass() == SC_Static)
+        CheckForConstantInitializer(Init, DclT);
+      // C89 is stricter than C99 for non-static aggregate types.
+      // C89 6.5.7p3: All the expressions [...] in an initializer list
+      // for an object that has aggregate or union type shall be
+      // constant expressions.
+      else if (!getLangOpts().C99 && VDecl->getType()->isAggregateType() &&
+               !Init->isConstantInitializer(Context, false))
+        Diag(Init->getExprLoc(),
+             diag::ext_aggregate_init_not_constant)
+          << Init->getSourceRange();
+    }
   } else if (VDecl->isStaticDataMember() &&
              VDecl->getLexicalDeclContext()->isRecord()) {
     // This is an in-class initialization for a static data member, e.g.,
diff --git a/clang/test/Sema/c89.c b/clang/test/Sema/c89.c
index a410a626eda..557acf6d62d 100644
--- a/clang/test/Sema/c89.c
+++ b/clang/test/Sema/c89.c
@@ -116,3 +116,7 @@ long long ll1 = /* expected-warning {{'long long' is an extension when C99 mode
 unsigned long long ull1 = /* expected-warning {{'long long' is an extension when C99 mode is not enabled}} */
                    42ULL; /* expected-warning {{'long long' is an extension when C99 mode is not enabled}} */
 
+void test17(int v, int w) {
+  int a[2] = { v, w }; /* expected-warning {{initializer for aggregate is not a compile-time constant}} */
+}
+