+2011-10-03 Bruno Haible <bruno@clisp.org>
+
+ relocatable-lib[-lgpl]: Avoid expensive /proc access on Linux, Cygwin.
+ * lib/relocatable.c (ENABLE_COSTLY_RELOCATABLE): New macro.
+ (compute_curr_prefix, shared_library_fullname,
+ find_shared_library_fullname, get_shared_library_fullname, relocate):
+ Use it together with PIC && INSTALLDIR.
+ Reported by <jojelino@gmail.com>
+ via Charles Wilson <cygwin@cwilson.fastmail.fm>.
+
2011-10-01 Jim Meyering <meyering@redhat.com>
maint.mk: adjust a release-related rule not to require use of gzip
# define FILE_SYSTEM_PREFIX_LEN(P) 0
#endif
+/* Whether to enable the more costly support for relocatable libraries.
+ It allows libraries to be have been installed with a different original
+ prefix than the program. But it is quite costly, especially on Cygwin
+ platforms, see below. Therefore we enable it by default only on native
+ Win32 platforms. */
+#ifndef ENABLE_COSTLY_RELOCATABLE
+# if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__
+# define ENABLE_COSTLY_RELOCATABLE 1
+# else
+# define ENABLE_COSTLY_RELOCATABLE 0
+# endif
+#endif
+
/* Original installation prefix. */
static char *orig_prefix;
static size_t orig_prefix_len;
#endif
}
-#if !defined IN_LIBRARY || (defined PIC && defined INSTALLDIR)
+#if !defined IN_LIBRARY || (defined PIC && defined INSTALLDIR && ENABLE_COSTLY_RELOCATABLE)
/* Convenience function:
Computes the current installation prefix, based on the original
#endif /* !IN_LIBRARY || PIC */
-#if defined PIC && defined INSTALLDIR
+#if defined PIC && defined INSTALLDIR && ENABLE_COSTLY_RELOCATABLE
/* Full pathname of shared library, or NULL. */
static char *shared_library_fullname;
#if (defined __linux__ && (__GLIBC__ >= 2 || defined __UCLIBC__)) || defined __CYGWIN__
/* Linux has /proc/self/maps. glibc 2 and uClibc have the getline()
function.
- Cygwin >= 1.5 has /proc/self/maps and the getline() function too. */
+ Cygwin >= 1.5 has /proc/self/maps and the getline() function too.
+ But it is costly: ca. 0.3 ms on Linux, 3 ms on Cygwin 1.5, and 5 ms on
+ Cygwin 1.7. */
FILE *fp;
/* Open the current process' maps file. It describes one VMA per line. */
const char *
relocate (const char *pathname)
{
-#if defined PIC && defined INSTALLDIR
+#if defined PIC && defined INSTALLDIR && ENABLE_COSTLY_RELOCATABLE
static int initialized;
/* Initialization code for a shared library. */