Fix a couple of bugs, add some new cool stuff.

1. Fix a todo in Parser::ParseTag, to recover better.  On code like
   that in test/Sema/decl-invalid.c it causes us to return a single
   error instead of multiple.
2. Fix an error in Sema::ParseDeclarator, where it would crash if the
   declarator didn't have an identifier.  Instead, diagnose the problem.
3. Start adding infrastructure to track the range of locations covered
   by a declspec or declarator.  This is mostly implemented for declspec,
   but could be improved, it is missing for declarator.

Thanks to Neil for pointing out this crash.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40482 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/INPUTS/macro_pounder_fn.c b/INPUTS/macro_pounder_fn.c
new file mode 100644
index 0000000..73f40a1
--- /dev/null
+++ b/INPUTS/macro_pounder_fn.c
@@ -0,0 +1,17 @@
+
+// This pounds on macro expansion for performance reasons.  This is currently
+// heavily constrained by darwin's malloc.
+
+// Function-like macros.
+#define A0(A, B) A B
+#define A1(A, B) A0(A,B) A0(A,B) A0(A,B) A0(A,B) A0(A,B) A0(A,B)
+#define A2(A, B) A1(A,B) A1(A,B) A1(A,B) A1(A,B) A1(A,B) A1(A,B)
+#define A3(A, B) A2(A,B) A2(A,B) A2(A,B) A2(A,B) A2(A,B) A2(A,B)
+#define A4(A, B) A3(A,B) A3(A,B) A3(A,B) A3(A,B) A3(A,B) A3(A,B)
+#define A5(A, B) A4(A,B) A4(A,B) A4(A,B) A4(A,B) A4(A,B) A4(A,B)
+#define A6(A, B) A5(A,B) A5(A,B) A5(A,B) A5(A,B) A5(A,B) A5(A,B)
+#define A7(A, B) A6(A,B) A6(A,B) A6(A,B) A6(A,B) A6(A,B) A6(A,B)
+#define A8(A, B) A7(A,B) A7(A,B) A7(A,B) A7(A,B) A7(A,B) A7(A,B)
+
+A8(a, b)
+