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

[Oleg Nesterov <oleg@redhat.com>]

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 <oleg@redhat.com>
---
 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