[PATCH 0/4] sparse/dissect: fix missing usage reports for unnamed members of named types

[PATCH 0/4] sparse/dissect: fix missing usage reports for unnamed members of named types

[Oleg Nesterov]

Hello,

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.

The only functional change is 4/4.

Oleg.
---

 dissect.c | 70 +++++++++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 50 insertions(+), 20 deletions(-)

[PATCH 1/4] sparse/dissect: introduce find_report_member()

[Oleg Nesterov]

No functional changes, preparation for the next patches.

Add the new helper, find_report_member(), which simply does
lookup_member() + report_member(), and update the current users of
the same pattern to use it.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 dissect.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/dissect.c b/dissect.c
index 04ec89ca..6b5cb0ef 100644
--- a/dissect.c
+++ b/dissect.c
@@ -331,6 +331,13 @@ static struct symbol *lookup_member(struct symbol *type, struct ident *name, int
 	return mem;
 }
 
+static struct symbol *find_report_member(usage_t mode, struct position *pos,
+					 struct symbol *type, struct ident *name,
+					 int *p_addr)
+{
+	return report_member(mode, pos, type, lookup_member(type, name, p_addr));
+}
+
 static struct expression *peek_preop(struct expression *expr, int op)
 {
 	do {
@@ -474,8 +481,8 @@ again:
 			p_mode = U_R_VAL;
 		p_type = do_expression(p_mode, expr->deref);
 
-		ret = report_member(mode, &expr->m_pos, p_type,
-			lookup_member(p_type, expr->member, NULL));
+		ret = find_report_member(mode, &expr->m_pos,
+					 p_type, expr->member, NULL);
 	}
 
 	break; case EXPR_OFFSETOF: {
@@ -483,8 +490,8 @@ again:
 
 		do {
 			if (expr->op == '.') {
-				in = report_member(U_VOID, &expr->pos, in,
-					lookup_member(in, expr->ident, NULL));
+				in = find_report_member(U_VOID, &expr->pos,
+							in, expr->ident, NULL);
 			} else {
 				do_expression(U_R_VAL, expr->index);
 				in = in->ctype.base_type;
@@ -609,8 +616,8 @@ static struct symbol *do_initializer(struct symbol *type, struct expression *exp
 
 				m_type = type;
 				while (m_expr->type == EXPR_IDENTIFIER) {
-					m_type = report_member(U_W_VAL, &m_expr->pos, m_type,
-							lookup_member(m_type, m_expr->expr_ident, m_atop));
+					m_type = find_report_member(U_W_VAL, &m_expr->pos,
+								    m_type, m_expr->expr_ident, m_atop);
 					m_expr = m_expr->ident_expression;
 					m_atop = NULL;
 
@@ -621,8 +628,8 @@ static struct symbol *do_initializer(struct symbol *type, struct expression *exp
 				}
 
 				if (m_atop) {
-					m_type = report_member(U_W_VAL, &m_expr->pos, m_type,
-							lookup_member(m_type, NULL, m_atop));
+					m_type = find_report_member(U_W_VAL, &m_expr->pos,
+								    m_type, NULL, m_atop);
 				}
 
 				if (m_expr->type != EXPR_INITIALIZER)
-- 
2.52.0

[PATCH 2/4] sparse/dissect: fold lookup_member() into find_report_member()

[Oleg Nesterov]

After the previous change lookup_member() has a single caller. Fold it
into find_report_member() and rename __lookup_member().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 dissect.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/dissect.c b/dissect.c
index 6b5cb0ef..c790807e 100644
--- a/dissect.c
+++ b/dissect.c
@@ -283,7 +283,7 @@ static struct symbol *base_type(struct symbol *sym)
 		?: &bad_ctype;
 }
 
-static struct symbol *__lookup_member(struct symbol *type, struct ident *name, int *p_addr)
+static struct symbol *lookup_member(struct symbol *type, struct ident *name, int *p_addr)
 {
 	struct symbol *node;
 	int addr = 0;
@@ -294,7 +294,7 @@ static struct symbol *__lookup_member(struct symbol *type, struct ident *name, i
 				return node;
 		}
 		else if (node->ident == NULL) {
-			node = __lookup_member(node->ctype.base_type, name, NULL);
+			node = lookup_member(node->ctype.base_type, name, NULL);
 			if (node)
 				goto found;
 		}
@@ -310,9 +310,11 @@ found:
 	return NULL;
 }
 
-static struct symbol *lookup_member(struct symbol *type, struct ident *name, int *addr)
+static struct symbol *find_report_member(usage_t mode, struct position *pos,
+					 struct symbol *type, struct ident *name,
+					 int *p_addr)
 {
-	struct symbol *mem = __lookup_member(type, name, addr);
+	struct symbol *mem = lookup_member(type, name, p_addr);
 
 	if (!mem) {
 		static struct symbol bad_member = {
@@ -328,14 +330,7 @@ static struct symbol *lookup_member(struct symbol *type, struct ident *name, int
 		mem->ident = name;
 	}
 
-	return mem;
-}
-
-static struct symbol *find_report_member(usage_t mode, struct position *pos,
-					 struct symbol *type, struct ident *name,
-					 int *p_addr)
-{
-	return report_member(mode, pos, type, lookup_member(type, name, p_addr));
+	return report_member(mode, pos, type, mem);
 }
 
 static struct expression *peek_preop(struct expression *expr, int op)
-- 
2.52.0

[PATCH 3/4] sparse/dissect: introduce struct lookup_args for lookup_member()

[Oleg Nesterov]

No functional changes, preparation for the next patch.

The new "struct lookup_args" bundles the current name/p_addr arguments
of lookup_member().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 dissect.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/dissect.c b/dissect.c
index c790807e..3da9e3a2 100644
--- a/dissect.c
+++ b/dissect.c
@@ -283,25 +283,29 @@ static struct symbol *base_type(struct symbol *sym)
 		?: &bad_ctype;
 }
 
-static struct symbol *lookup_member(struct symbol *type, struct ident *name, int *p_addr)
+struct lookup_args {
+	struct ident *name;
+	int *p_addr;
+};
+
+static struct symbol *lookup_member(struct symbol *type, struct lookup_args *la)
 {
 	struct symbol *node;
 	int addr = 0;
 
 	FOR_EACH_PTR(type->symbol_list, node)
-		if (!name) {
-			if (addr == *p_addr)
+		if (!la->name) {
+			if (*la->p_addr == addr)
 				return node;
 		}
 		else if (node->ident == NULL) {
-			node = lookup_member(node->ctype.base_type, name, NULL);
+			node = lookup_member(node->ctype.base_type, la);
 			if (node)
 				goto found;
 		}
-		else if (node->ident == name) {
-found:
-			if (p_addr)
-				*p_addr = addr;
+		else if (node->ident == la->name) {
+found:			if (la->p_addr)
+				*la->p_addr = addr;
 			return node;
 		}
 		addr++;
@@ -314,7 +318,11 @@ static struct symbol *find_report_member(usage_t mode, struct position *pos,
 					 struct symbol *type, struct ident *name,
 					 int *p_addr)
 {
-	struct symbol *mem = lookup_member(type, name, p_addr);
+	struct lookup_args la = {
+		.name	= name,
+		.p_addr	= p_addr,
+	};
+	struct symbol *mem = lookup_member(type, &la);
 
 	if (!mem) {
 		static struct symbol bad_member = {
-- 
2.52.0

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

[Oleg Nesterov]

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