dissect: use struct symbol::visited/inspected instead of ::examined/evaluated

The dissect client uses struct symbol's fields 'examined' & 'evaluated'
to avoid reprocessing the same symbols. But these fields are used
internally by sparse for type examination & evaluation and despite
dissect not doing these operations explicitly, they can be done
implicitly (for example to handle static assertions or when the
value of a constant expression is needed) inside __sparse().

If this happens, dissect.c:examine_sym_node() will be a no-op because
node->examined will already be set and node->kind would be 0.
Same can happen with node->evaluated.

So, add a new field to struct symbol: 'inspected' and use it, as
well as the existing 'visited', instead of 'evaluated' & 'examined'.
This way, dissect will control its recursion via flags reserved for
backends and thus never set by sparse internals.

Note: when used on the kernel, this patch avoids a lot of warnings:
	"warning: r_member bad sym type=7 kind=0"
	"warning: r_member bad mem->kind = 0"
      and creates substantially more normal output.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>

2 files changed, 7 insertions, 6 deletions

diff --git a/dissect.c b/dissect.c
index a633c8bf..0272ebd2 100644
--- a/dissect.c
+++ b/dissect.c
@@ -204,9 +204,9 @@ static void examine_sym_node(struct symbol *node, struct symbol *parent)
 	struct ident *name = node->ident;
 	struct symbol *base, *dctx;
 
-	if (node->examined)
+	if (node->visited)
 		return;
-	node->examined = 1;
+	node->visited = 1;
 	node->kind = 'v';
 
 	while ((base = node->ctype.base_type) != NULL)
@@ -228,9 +228,9 @@ static void examine_sym_node(struct symbol *node, struct symbol *parent)
 			break;
 
 		case SYM_STRUCT: case SYM_UNION: //case SYM_ENUM:
-			if (base->evaluated)
+			if (base->inspected)
 				return;
-			base->evaluated = 1;
+			base->inspected = 1;
 			base->kind = 's';
 
 			if (!base->symbol_list)
diff --git a/symbol.h b/symbol.h
index c2b60ce9..3ec68e2e 100644
--- a/symbol.h
+++ b/symbol.h
@@ -206,9 +206,10 @@ struct symbol {
 	union /* backend */ {
 		struct basic_block *bb_target;	/* label */
 		void *aux;			/* Auxiliary info, e.g. backend information */
-		struct {			/* sparse ctags */
-			char kind;
+		struct {
+			char kind;		/* used by ctags & dissect */
 			unsigned char visited:1;
+			unsigned char inspected:1;
 		};
 	};
 	pseudo_t pseudo;