Step #1/N of implementing support for __label__: split labels into

LabelDecl and LabelStmt.  There is a 1-1 correspondence between the
two, but this simplifies a bunch of code by itself.  This is because
labels are the only place where we previously had references to random
other statements, causing grief for AST serialization and other stuff.

This does cause one regression (attr(unused) doesn't silence unused
label warnings) which I'll address next.

This does fix some minor bugs:
1. "The only valid attribute " diagnostic was capitalized.
2. Various diagnostics printed as ''labelname'' instead of 'labelname'
3. This reduces duplication of label checking between functions and blocks.

Review appreciated, particularly for the cindex and template bits.

llvm-svn: 125733

1 files changed, 2 insertions, 2 deletions

diff --git a/clang/test/Sema/warn-unused-label.c b/clang/test/Sema/warn-unused-label.c
index 163446002e6..03be7da2fc9 100644
--- a/clang/test/Sema/warn-unused-label.c
+++ b/clang/test/Sema/warn-unused-label.c
@@ -4,8 +4,8 @@ void f() {
   a:
   goto a;
   b: // expected-warning{{unused}}
-  c: __attribute__((unused));
-  d: __attribute__((noreturn)); // expected-warning {{The only valid attribute for labels is 'unused'}}
+  c: __attribute__((unused));    // expected-warning {{unused label 'c'}}
+  d: __attribute__((noreturn)); // expected-warning {{the only valid attribute for labels is 'unused'}}
   goto d;
   return;
 }