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Re: [GLIBC][PATCH v2] Remove strdup inlines
- From: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- To: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
- Cc: nd <nd at arm dot com>
- Date: Thu, 9 Feb 2017 15:35:04 +0000
- Subject: Re: [GLIBC][PATCH v2] Remove strdup inlines
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From: Wilco Dijkstra
Sent: 12 December 2016 13:02
To: Zack Weinberg
Cc: libc-alpha@sourceware.org; nd
Subject: Re: [GLIBC][PATCH v2] Remove strdup inlines
Remove the str(n)dup inlines from string/bits/string2.h. Although inlining
calls with constant strings shows a small (~10%) performance gain, strdup is
typically used in error reporting code, so not performance critical.
Remove the now unused __need_malloc_and_calloc related defines from stdlib.h.
Avoid linknamespace and localplt failures by redirecting str(n)dup to GCC
builtins.
ChangeLog:
2015-12-12 Wilco Dijkstra <wdijkstr@arm.com>
* include/stdlib.h (__need_malloc_and_calloc): Remove uses.
(__Need_M_And_C) Remove define/undef.
* stdlib/stdlib.h (__need_malloc_and_calloc): Remove uses.
(__malloc_and_calloc_defined): Remove define.
* string/string.h (strdup): Use builtin.
(strndup): Likewise.
* string/bits/string2.h (__strdup): Remove define.
(strdup): Likewise.
(__strndup): Likewise.
(strndup): Likewise.
--
diff --git a/include/stdlib.h b/include/stdlib.h
index 352339e8595eb8229018cb27f7d2decf63f511c7..929cead59ae10afe03ae1286b72d8321f0ab2d90 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -1,16 +1,12 @@
#ifndef _STDLIB_H
-#ifdef __need_malloc_and_calloc
-#define __Need_M_And_C
-#endif
-
#ifndef _ISOMAC
# include <stddef.h>
#endif
#include <stdlib/stdlib.h>
/* Now define the internal interfaces. */
-#if !defined __Need_M_And_C && !defined _ISOMAC
+#if !defined _ISOMAC
# include <sys/stat.h>
__BEGIN_DECLS
@@ -269,6 +265,4 @@ __END_DECLS
#endif
-#undef __Need_M_And_C
-
#endif /* include/stdlib.h */
diff --git a/stdlib/stdlib.h b/stdlib/stdlib.h
index 48f9a9500e736a5d85e5eca2e511cff374e43226..b1696c7a8d82145f76760a49909e24c288c51263 100644
--- a/stdlib/stdlib.h
+++ b/stdlib/stdlib.h
@@ -26,15 +26,12 @@
/* Get size_t, wchar_t and NULL from <stddef.h>. */
#define __need_size_t
-#ifndef __need_malloc_and_calloc
-# define __need_wchar_t
-# define __need_NULL
-#endif
+#define __need_wchar_t
+#define __need_NULL
#include <stddef.h>
__BEGIN_DECLS
-#ifndef __need_malloc_and_calloc
#define _STDLIB_H 1
#if (defined __USE_XOPEN || defined __USE_XOPEN2K8) && !defined _SYS_WAIT_H
@@ -434,10 +431,6 @@ extern int lcong48_r (unsigned short int __param[7],
# endif /* Use misc. */
#endif /* Use misc or X/Open. */
-#endif /* don't just need malloc and calloc */
-
-#ifndef __malloc_and_calloc_defined
-# define __malloc_and_calloc_defined
__BEGIN_NAMESPACE_STD
/* Allocate SIZE bytes of memory. */
extern void *malloc (size_t __size) __THROW __attribute_malloc__ __wur;
@@ -445,9 +438,7 @@ extern void *malloc (size_t __size) __THROW __attribute_malloc__ __wur;
extern void *calloc (size_t __nmemb, size_t __size)
__THROW __attribute_malloc__ __wur;
__END_NAMESPACE_STD
-#endif
-#ifndef __need_malloc_and_calloc
__BEGIN_NAMESPACE_STD
/* Re-allocate the previously allocated block
in PTR, making the new block SIZE bytes long. */
@@ -944,9 +935,6 @@ extern int ttyslot (void) __THROW;
# include <bits/stdlib-ldbl.h>
#endif
-#endif /* don't just need malloc and calloc */
-#undef __need_malloc_and_calloc
-
__END_DECLS
#endif /* stdlib.h */
diff --git a/string/bits/string2.h b/string/bits/string2.h
index 03af22cc27a33c81f36d56ddc52fce0a5ea81ece..b0be5f6a49024a0bedfc37e9ec2c0356e0e4fa09 100644
--- a/string/bits/string2.h
+++ b/string/bits/string2.h
@@ -118,58 +118,6 @@
#endif
-/* We need the memory allocation functions for inline strdup().
- Referring to stdlib.h (even minimally) is not allowed
- in any of the tight standards compliant modes. */
-#ifdef __USE_MISC
-
-# define __need_malloc_and_calloc
-# include <stdlib.h>
-
-extern char *__strdup (const char *__string) __THROW __attribute_malloc__;
-# define __strdup(s) \
- (__extension__ (__builtin_constant_p (s) && __string2_1bptr_p (s) \
- ? (((const char *) (s))[0] == '\0' \
- ? (char *) calloc ((size_t) 1, (size_t) 1) \
- : ({ size_t __len = strlen (s) + 1; \
- char *__retval = (char *) malloc (__len); \
- if (__retval != NULL) \
- __retval = (char *) memcpy (__retval, s, __len); \
- __retval; })) \
- : __strdup (s)))
-
-# if defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8
-# define strdup(s) __strdup (s)
-# endif
-
-
-extern char *__strndup (const char *__string, size_t __n)
- __THROW __attribute_malloc__;
-# define __strndup(s, n) \
- (__extension__ (__builtin_constant_p (s) && __string2_1bptr_p (s) \
- ? (((const char *) (s))[0] == '\0' \
- ? (char *) calloc ((size_t) 1, (size_t) 1) \
- : ({ size_t __len = strlen (s) + 1; \
- size_t __n = (n); \
- char *__retval; \
- if (__n < __len) \
- __len = __n + 1; \
- __retval = (char *) malloc (__len); \
- if (__retval != NULL) \
- { \
- __retval[__len - 1] = '\0'; \
- __retval = (char *) memcpy (__retval, s, \
- __len - 1); \
- } \
- __retval; })) \
- : __strndup (s, n)))
-
-# ifdef __USE_XOPEN2K8
-# define strndup(s, n) __strndup (s, n)
-# endif
-
-#endif /* Use misc. or use GNU. */
-
#ifndef _FORCE_INLINES
# undef __STRING_INLINE
#endif
diff --git a/string/string.h b/string/string.h
index b103e64912fe1904098e229ccb845bb2c5c10835..c251cc603a1dbb5bef469d4b71f90037612d36f0 100644
--- a/string/string.h
+++ b/string/string.h
@@ -636,6 +636,15 @@ extern char *basename (const char *__filename) __THROW __nonnull ((1));
# endif
#endif
+#if (defined __USE_XOPEN_EXTENDED || defined __USE_XOPEN2K8 \
+ || __GLIBC_USE (LIB_EXT2))
+# define strdup(s) __builtin_strdup (s)
+#endif
+
+#if defined __USE_XOPEN2K8 || __GLIBC_USE (LIB_EXT2)
+#define strndup(s,n) __builtin_strndup (s, n)
+#endif
+
#if defined __USE_GNU && defined __OPTIMIZE__ \
&& defined __extern_always_inline && __GNUC_PREREQ (3,2)
# if !defined _FORCE_INLINES && !defined _HAVE_STRING_ARCH_mempcpy