Re: Some functions are not inlined by gcc 3.2, resulting code is ugly

From: J.A. Magallón (jamagallon@able.es)
Date: Tue Nov 12 2002 - 20:28:54 EST

On 2002.11.04 Denis Vlasenko wrote:
[...]
> __constant_c_and_count_memset *has to* be inlined.
> There is large switch statement which meant to be optimized out.
> It does optimize out *only if* count is compile-time constant.

I also got tons of __copy_to_user and __copy_from_user in 2.4.
Do not show in 2.5 ?

This i what I applied to my 2.4 tree:

diff -urN linux-2.5.45.orig/include/linux/compiler.h linux-2.5.45fix/include/linux/compiler.h
--- linux-2.5.45.orig/include/linux/compiler.h Wed Oct 30 22:43:05 2002
+++ linux-2.5.45fix/include/linux/compiler.h Sun Nov 3 15:19:20 2002
@@ -13,4 +13,12 @@
 #define likely(x) __builtin_expect((x),1)
 #define unlikely(x) __builtin_expect((x),0)
 
+/* GCC 3 (and probably earlier, I'm not sure) can be told to always inline
+ a function. */
+#if __GNUC__ < 3
+#define force_inline inline
+#else
+#define force_inline inline __attribute__ ((always_inline))
+#endif
+
 #endif /* __LINUX_COMPILER_H */
diff -urN linux-2.5.45.orig/include/asm-i386/string.h linux-2.5.45fix/include/asm-i386/string.h
--- linux-2.5.45.orig/include/asm-i386/string.h Wed Oct 30 22:43:46 2002
+++ linux-2.5.45fix/include/asm-i386/string.h Sun Nov 3 15:58:08 2002
@@ -3,6 +3,7 @@

 #ifdef __KERNEL__
 #include <linux/config.h>
+#include <linux/compiler.h>
 /*
  * On a 486 or Pentium, we are better off not using the
  * byte string operations. But on a 386 or a PPro the
@@ -218,7 +219,7 @@
  * This looks horribly ugly, but the compiler can optimize it totally,
  * as the count is constant.
  */
-static inline void * __constant_memcpy(void * to, const void * from, size_t n)
+static force_inline void * __constant_memcpy(void * to, const void * from, size_t n)
 {
         switch (n) {
                 case 0:
@@ -453,7 +454,7 @@
  * This looks horribly ugly, but the compiler can optimize it totally,
  * as we by now know that both pattern and count is constant..
  */
-static inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count)
+static force_inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count)
 {
         switch (count) {
                 case 0:
--- linux/include/asm-i386/uaccess.h.orig 2002-11-13 01:27:42.000000000 +0100
+++ linux/include/asm-i386/uaccess.h 2002-11-13 01:30:04.000000000 +0100
@@ -543,7 +543,7 @@
 unsigned long __generic_copy_to_user(void *, const void *, unsigned long);
 unsigned long __generic_copy_from_user(void *, const void *, unsigned long);
 
-static inline unsigned long
+static force_inline unsigned long
 __constant_copy_to_user(void *to, const void *from, unsigned long n)
 {
         prefetch(from);
@@ -552,7 +552,7 @@
         return n;
 }
 
-static inline unsigned long
+static force_inline unsigned long
 __constant_copy_from_user(void *to, const void *from, unsigned long n)
 {
         if (access_ok(VERIFY_READ, from, n))
@@ -562,14 +562,14 @@
         return n;
 }
 
-static inline unsigned long
+static force_inline unsigned long
 __constant_copy_to_user_nocheck(void *to, const void *from, unsigned long n)
 {
         __constant_copy_user(to,from,n);
         return n;
 }
 
-static inline unsigned long
+static force_inline unsigned long
 __constant_copy_from_user_nocheck(void *to, const void *from, unsigned long n)
 {
         __constant_copy_user_zeroing(to,from,n); 

-- 
J.A. Magallon <jamagallon@able.es>      \                 Software is like sex:
werewolf.able.es                         \           It's better when it's free
Mandrake Linux release 9.1 (Cooker) for i586
Linux 2.4.20-rc1-jam2 (gcc 3.2 (Mandrake Linux 9.1 3.2-3mdk))
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This archive was generated by hypermail 2b29 : Fri Nov 15 2002 - 22:00:27 EST