[Sema] Issue a warning for integer overflow in nested struct initializer

r257357 fixed clang to warn on integer overflow in struct initializers.
However, it didn't warn when a struct had a nested initializer. This
commit makes changes in Sema::CheckForIntOverflow to handle nested
initializers.

For example:

struct s {
  struct t {
    unsigned x;
  } t;
} s = {
  {
    .x = 4 * 1024 * 1024 * 1024
  }
};

rdar://problem/23526454

llvm-svn: 260360

1 files changed, 20 insertions, 0 deletions

diff --git a/clang/test/Sema/integer-overflow.c b/clang/test/Sema/integer-overflow.c
index db5c1f4c711..02d99b3fc5c 100644
--- a/clang/test/Sema/integer-overflow.c
+++ b/clang/test/Sema/integer-overflow.c
@@ -153,3 +153,23 @@ struct s {
   .y = 5,
   .x = 4 * 1024 * 1024 * 1024  // expected-warning {{overflow in expression; result is 0 with type 'int'}}
 };
+
+struct s2 {
+  unsigned a0;
+
+  struct s3 {
+    unsigned a2;
+
+    struct s4 {
+      unsigned a4;
+    } a3;
+  } a1;
+} s2 = {
+  .a0 = 4 * 1024 * 1024 * 1024, // expected-warning {{overflow in expression; result is 0 with type 'int'}}
+  {
+    .a2 = 4 * 1024 * 1024 * 1024, // expected-warning {{overflow in expression; result is 0 with type 'int'}}
+    {
+      .a4 = 4 * 1024 * 1024 * 1024 // expected-warning {{overflow in expression; result is 0 with type 'int'}}
+    }
+  }
+};