[PATCH v2 7/8] lib: move bsearch code

[Jan Beulich <jbeulich@xxxxxxxx>]

Convert this code to an inline function (backed by an instance in an
archive in case the compiler decides against inlining), which results
in not having it in x86 final binaries. This saves a little bit of dead
code.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v2: Make the function an extern inline in its header.
---
 xen/common/Makefile        |  1 -
 xen/common/bsearch.c       | 51 --------------------------------------
 xen/include/xen/compiler.h |  1 +
 xen/include/xen/lib.h      | 42 ++++++++++++++++++++++++++++++-
 xen/lib/Makefile           |  1 +
 xen/lib/bsearch.c          | 13 ++++++++++
 6 files changed, 56 insertions(+), 53 deletions(-)
 delete mode 100644 xen/common/bsearch.c
 create mode 100644 xen/lib/bsearch.c

diff --git a/xen/common/Makefile b/xen/common/Makefile
index 7bb779f780a1..d8519a2cc163 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -1,6 +1,5 @@
 obj-$(CONFIG_ARGO) += argo.o
 obj-y += bitmap.o
-obj-y += bsearch.o
 obj-$(CONFIG_HYPFS_CONFIG) += config_data.o
 obj-$(CONFIG_CORE_PARKING) += core_parking.o
 obj-y += cpu.o
diff --git a/xen/common/bsearch.c b/xen/common/bsearch.c
deleted file mode 100644
index 7090930aab5c..000000000000
--- a/xen/common/bsearch.c
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * A generic implementation of binary search for the Linux kernel
- *
- * Copyright (C) 2008-2009 Ksplice, Inc.
- * Author: Tim Abbott <tabbott@xxxxxxxxxxx>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; version 2.
- */
-
-#include <xen/lib.h>
-
-/*
- * bsearch - binary search an array of elements
- * @key: pointer to item being searched for
- * @base: pointer to first element to search
- * @num: number of elements
- * @size: size of each element
- * @cmp: pointer to comparison function
- *
- * This function does a binary search on the given array.  The
- * contents of the array should already be in ascending sorted order
- * under the provided comparison function.
- *
- * Note that the key need not have the same type as the elements in
- * the array, e.g. key could be a string and the comparison function
- * could compare the string with the struct's name field.  However, if
- * the key and elements in the array are of the same type, you can use
- * the same comparison function for both sort() and bsearch().
- */
-void *bsearch(const void *key, const void *base, size_t num, size_t size,
-             int (*cmp)(const void *key, const void *elt))
-{
-       size_t start = 0, end = num;
-       int result;
-
-       while (start < end) {
-               size_t mid = start + (end - start) / 2;
-
-               result = cmp(key, base + mid * size);
-               if (result < 0)
-                       end = mid;
-               else if (result > 0)
-                       start = mid + 1;
-               else
-                       return (void *)base + mid * size;
-       }
-
-       return NULL;
-}
diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h
index c0e0ee9f27be..2b7acdf3b188 100644
--- a/xen/include/xen/compiler.h
+++ b/xen/include/xen/compiler.h
@@ -12,6 +12,7 @@
 
 #define inline        __inline__
 #define always_inline __inline__ __attribute__ ((__always_inline__))
+#define gnu_inline    __inline__ __attribute__ ((__gnu_inline__))
 #define noinline      __attribute__((__noinline__))
 
 #define noreturn      __attribute__((__noreturn__))
diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h
index 076bcfb67dbb..940d23755661 100644
--- a/xen/include/xen/lib.h
+++ b/xen/include/xen/lib.h
@@ -192,8 +192,48 @@ void dump_execstate(struct cpu_user_regs *);
 
 void init_constructors(void);
 
+/*
+ * bsearch - binary search an array of elements
+ * @key: pointer to item being searched for
+ * @base: pointer to first element to search
+ * @num: number of elements
+ * @size: size of each element
+ * @cmp: pointer to comparison function
+ *
+ * This function does a binary search on the given array.  The
+ * contents of the array should already be in ascending sorted order
+ * under the provided comparison function.
+ *
+ * Note that the key need not have the same type as the elements in
+ * the array, e.g. key could be a string and the comparison function
+ * could compare the string with the struct's name field.  However, if
+ * the key and elements in the array are of the same type, you can use
+ * the same comparison function for both sort() and bsearch().
+ */
+#ifndef BSEARCH_IMPLEMENTATION
+extern gnu_inline
+#endif
 void *bsearch(const void *key, const void *base, size_t num, size_t size,
-              int (*cmp)(const void *key, const void *elt));
+              int (*cmp)(const void *key, const void *elt))
+{
+    size_t start = 0, end = num;
+    int result;
+
+    while ( start < end )
+    {
+        size_t mid = start + (end - start) / 2;
+
+        result = cmp(key, base + mid * size);
+        if ( result < 0 )
+            end = mid;
+        else if ( result > 0 )
+            start = mid + 1;
+        else
+            return (void *)base + mid * size;
+    }
+
+    return NULL;
+}
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/xen/lib/Makefile b/xen/lib/Makefile
index b469d2dff7b8..122eeb3d327b 100644
--- a/xen/lib/Makefile
+++ b/xen/lib/Makefile
@@ -1,6 +1,7 @@
 obj-y += ctors.o
 obj-$(CONFIG_X86) += x86/
 
+lib-y += bsearch.o
 lib-y += ctype.o
 lib-y += list-sort.o
 lib-y += parse-size.o
diff --git a/xen/lib/bsearch.c b/xen/lib/bsearch.c
new file mode 100644
index 000000000000..149f7feafd1f
--- /dev/null
+++ b/xen/lib/bsearch.c
@@ -0,0 +1,13 @@
+/*
+ * A generic implementation of binary search for the Linux kernel
+ *
+ * Copyright (C) 2008-2009 Ksplice, Inc.
+ * Author: Tim Abbott <tabbott@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2.
+ */
+
+#define BSEARCH_IMPLEMENTATION
+#include <xen/lib.h>
-- 
2.22.0