[PATCH 4/4] sparse/dissect: fix missing usage reports for unnamed members of named types

With the recent change, dissect.c correctly reports the definitions of the
promoted members, but it still doesn't report the usages of the underlying
members.

This means, for example, that

	$ semind search -m r ns_tree.ns_id

finds nothing without this change.

Minimal (same) test-case:

	union U { int i; };

	struct S { union U; } v = { .i = 0 };

Before the patch:

	$ test-dissect TEST.c
	3:8                    def   s S
	1:7                    def   s U
	1:15                   def   m U.i                              int
	3:19                   def   m S.i                              int
	3:23                   def   v v                                struct S
	3:23                   -w-   v v                                struct S
	3:30  v                -w-   m S.i                              int

The usage of U.i is not reported.

After the patch:

	$ test-dissect TEST.c
	3:8                    def   s S
	1:7                    def   s U
	1:15                   def   m U.i                              int
	3:19                   def   m S.i                              int
	3:23                   def   v v                                struct S
	3:23                   -w-   v v                                struct S
	3:30  v                -w-   m U.i                              int
	3:30  v                -w-   m S.i                              int

Signed-off-by: Oleg Nesterov <[email protected]>
---
 dissect.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/dissect.c b/dissect.c
index 3da9e3a2..2358297b 100644
--- a/dissect.c
+++ b/dissect.c
@@ -286,8 +286,19 @@ static struct symbol *base_type(struct symbol *sym)
 struct lookup_args {
 	struct ident *name;
 	int *p_addr;
+	struct position pos;
+	struct symbol *stack[8];
+	unsigned int depth;
 };
 
+static inline void lookup_push(struct lookup_args *la, struct symbol *type)
+{
+	if (la->depth == ARRAY_SIZE(la->stack))
+		warning(la->pos, "lookup stack overflow");
+	else
+		la->stack[la->depth++] = type;
+}
+
 static struct symbol *lookup_member(struct symbol *type, struct lookup_args *la)
 {
 	struct symbol *node;
@@ -299,9 +310,13 @@ static struct symbol *lookup_member(struct symbol *type, struct lookup_args *la)
 				return node;
 		}
 		else if (node->ident == NULL) {
-			node = lookup_member(node->ctype.base_type, la);
-			if (node)
+			struct symbol *base = node->ctype.base_type;
+			node = lookup_member(base, la);
+			if (node) {
+				if (type->ident != base->ident)
+					lookup_push(la, base);
 				goto found;
+			}
 		}
 		else if (node->ident == la->name) {
 found:			if (la->p_addr)
@@ -321,6 +336,8 @@ static struct symbol *find_report_member(usage_t mode, struct position *pos,
 	struct lookup_args la = {
 		.name	= name,
 		.p_addr	= p_addr,
+		.pos	= *pos,
+		.depth	= 0,
 	};
 	struct symbol *mem = lookup_member(type, &la);
 
@@ -338,6 +355,9 @@ static struct symbol *find_report_member(usage_t mode, struct position *pos,
 		mem->ident = name;
 	}
 
+	while (la.depth)
+		report_member(mode, pos, la.stack[--la.depth], mem);
+
 	return report_member(mode, pos, type, mem);
 }
 
-- 
2.52.0