[LEDE-DEV] [PATCH 1/2] libubox: Add pure attribute to several functions.

[Rosen Penev]

Manually adding pure allows the compiler to optimize several functions for better performance. All were found with gcc's -Wsuggest-attribute=pure. The switch is conservative meaning there are more such functions.

Signed-off by: Rosen Penev <rosenp at gmail.com>
---
 avl-cmp.h | 6 ++++--
 avl.c     | 2 ++
 blob.h    | 4 ++--
 blobmsg.h | 6 +++---
 jshn.c    | 1 +
 kvlist.h  | 4 ++--
 utils.h   | 4 ++++
 7 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/avl-cmp.h b/avl-cmp.h
index f97ae8d..ea415b3 100644
--- a/avl-cmp.h
+++ b/avl-cmp.h
@@ -16,7 +16,9 @@
 #ifndef __AVL_CMP_H
 #define __AVL_CMP_H
 
-int avl_strcmp(const void *k1, const void *k2, void *ptr);
-int avl_blobcmp(const void *k1, const void *k2, void *ptr);
+#include "utils.h"
+
+int avl_strcmp(const void *k1, const void *k2, void *ptr) __pure;
+int avl_blobcmp(const void *k1, const void *k2, void *ptr) __pure;
 
 #endif
diff --git a/avl.c b/avl.c
index 8d0bf65..424ce45 100644
--- a/avl.c
+++ b/avl.c
@@ -46,6 +46,7 @@
 
 #include "avl.h"
 #include "list.h"
+#include "utils.h"
 
 /**
  * internal type save inline function to calculate the maximum of
@@ -569,6 +570,7 @@ avl_post_delete(struct avl_tree *tree, struct avl_node *node)
   avl_post_delete(tree, parent->parent);
 }
 
+__pure
 static struct avl_node *
 avl_local_min(struct avl_node *node)
 {
diff --git a/blob.h b/blob.h
index ab077ea..d63b954 100644
--- a/blob.h
+++ b/blob.h
@@ -188,7 +188,7 @@ blob_next(const struct blob_attr *attr)
 
 extern void blob_fill_pad(struct blob_attr *attr);
 extern void blob_set_raw_len(struct blob_attr *attr, unsigned int len);
-extern bool blob_attr_equal(const struct blob_attr *a1, const struct blob_attr *a2);
+extern bool blob_attr_equal(const struct blob_attr *a1, const struct blob_attr *a2) __pure;
 extern int blob_buf_init(struct blob_buf *buf, int id);
 extern void blob_buf_free(struct blob_buf *buf);
 extern bool blob_buf_grow(struct blob_buf *buf, int required);
@@ -196,7 +196,7 @@ extern struct blob_attr *blob_new(struct blob_buf *buf, int id, int payload);
 extern void *blob_nest_start(struct blob_buf *buf, int id);
 extern void blob_nest_end(struct blob_buf *buf, void *cookie);
 extern struct blob_attr *blob_put(struct blob_buf *buf, int id, const void *ptr, unsigned int len);
-extern bool blob_check_type(const void *ptr, unsigned int len, int type);
+extern bool blob_check_type(const void *ptr, unsigned int len, int type) __pure;
 extern int blob_parse(struct blob_attr *attr, struct blob_attr **data, const struct blob_attr_info *info, int max);
 extern struct blob_attr *blob_memdup(struct blob_attr *attr);
 extern struct blob_attr *blob_put_raw(struct blob_buf *buf, const void *ptr, unsigned int len);
diff --git a/blobmsg.h b/blobmsg.h
index 84997a6..3114425 100644
--- a/blobmsg.h
+++ b/blobmsg.h
@@ -94,8 +94,8 @@ static inline int blobmsg_len(const struct blob_attr *attr)
 	return blobmsg_data_len(attr);
 }
 
-bool blobmsg_check_attr(const struct blob_attr *attr, bool name);
-bool blobmsg_check_attr_list(const struct blob_attr *attr, int type);
+bool blobmsg_check_attr(const struct blob_attr *attr, bool name) __pure;
+bool blobmsg_check_attr_list(const struct blob_attr *attr, int type) __pure;
 
 /*
  * blobmsg_check_array: validate array/table and return size
@@ -103,7 +103,7 @@ bool blobmsg_check_attr_list(const struct blob_attr *attr, int type);
  * Checks if all elements of an array or table are valid and have
  * the specified type. Returns the number of elements in the array
  */
-int blobmsg_check_array(const struct blob_attr *attr, int type);
+int blobmsg_check_array(const struct blob_attr *attr, int type) __pure;
 
 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
                   struct blob_attr **tb, void *data, unsigned int len);
diff --git a/jshn.c b/jshn.c
index 4989099..9e3c3f4 100644
--- a/jshn.c
+++ b/jshn.c
@@ -304,6 +304,7 @@ static int usage(const char *progname)
 	return 2;
 }
 
+__pure
 static int avl_strcmp_var(const void *k1, const void *k2, void *ptr)
 {
 	const char *s1 = k1;
diff --git a/kvlist.h b/kvlist.h
index eaa691c..86abfb4 100644
--- a/kvlist.h
+++ b/kvlist.h
@@ -58,7 +58,7 @@ void *kvlist_get(struct kvlist *kv, const char *name);
 bool kvlist_set(struct kvlist *kv, const char *name, const void *data);
 bool kvlist_delete(struct kvlist *kv, const char *name);
 
-int kvlist_strlen(struct kvlist *kv, const void *data);
-int kvlist_blob_len(struct kvlist *kv, const void *data);
+int kvlist_strlen(struct kvlist *kv, const void *data) __pure;
+int kvlist_blob_len(struct kvlist *kv, const void *data) __pure;
 
 #endif
diff --git a/utils.h b/utils.h
index d00e76b..dc4a88a 100644
--- a/utils.h
+++ b/utils.h
@@ -156,6 +156,10 @@ static inline uint16_t __u_bswap16(uint16_t val)
 #define __packed __attribute__((packed))
 #endif
 
+#ifndef __pure
+#define __pure __attribute__((pure))
+#endif
+
 #ifndef __constructor
 #define __constructor __attribute__((constructor))
 #endif
-- 
2.7.4