forked from Imagelibrary/binutils-gdb
Use mmap and cache the view buffer for get_view
This patch uses mmap if it is available and works. It also caches the view buffer for get_view. * configure.ac: Add AC_FUNC_MMAP. * config.in: Regenerated. * configure: Likewise. * plugin.c: Include <sys/mman.h>. (MAP_FAILED): New. Defined if not defined. (PROT_READ): Likewise. (MAP_PRIVATE): Likewise. (view_buffer_t): New. (plugin_input_file_t): Add view_buffer. (get_view): Try mmap and cache the view buffer. (plugin_maybe_claim): Initialize view_buffer.
This commit is contained in:
H.J. Lu
182
ld/configure
vendored
182
ld/configure
vendored
@@ -16549,6 +16549,188 @@ fi
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fi
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for ac_header in stdlib.h unistd.h
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do :
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as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
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ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
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eval as_val=\$$as_ac_Header
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if test "x$as_val" = x""yes; then :
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cat >>confdefs.h <<_ACEOF
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#define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
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_ACEOF
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fi
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done
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for ac_func in getpagesize
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do :
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ac_fn_c_check_func "$LINENO" "getpagesize" "ac_cv_func_getpagesize"
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if test "x$ac_cv_func_getpagesize" = x""yes; then :
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cat >>confdefs.h <<_ACEOF
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#define HAVE_GETPAGESIZE 1
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_ACEOF
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fi
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done
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for working mmap" >&5
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$as_echo_n "checking for working mmap... " >&6; }
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if test "${ac_cv_func_mmap_fixed_mapped+set}" = set; then :
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$as_echo_n "(cached) " >&6
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else
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if test "$cross_compiling" = yes; then :
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ac_cv_func_mmap_fixed_mapped=no
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else
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cat confdefs.h - <<_ACEOF >conftest.$ac_ext
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/* end confdefs.h. */
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$ac_includes_default
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/* malloc might have been renamed as rpl_malloc. */
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#undef malloc
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/* Thanks to Mike Haertel and Jim Avera for this test.
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Here is a matrix of mmap possibilities:
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mmap private not fixed
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mmap private fixed at somewhere currently unmapped
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mmap private fixed at somewhere already mapped
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mmap shared not fixed
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mmap shared fixed at somewhere currently unmapped
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mmap shared fixed at somewhere already mapped
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For private mappings, we should verify that changes cannot be read()
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back from the file, nor mmap's back from the file at a different
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address. (There have been systems where private was not correctly
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implemented like the infamous i386 svr4.0, and systems where the
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VM page cache was not coherent with the file system buffer cache
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like early versions of FreeBSD and possibly contemporary NetBSD.)
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For shared mappings, we should conversely verify that changes get
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propagated back to all the places they're supposed to be.
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Grep wants private fixed already mapped.
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The main things grep needs to know about mmap are:
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* does it exist and is it safe to write into the mmap'd area
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* how to use it (BSD variants) */
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#include <fcntl.h>
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#include <sys/mman.h>
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#if !defined STDC_HEADERS && !defined HAVE_STDLIB_H
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char *malloc ();
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#endif
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/* This mess was copied from the GNU getpagesize.h. */
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#ifndef HAVE_GETPAGESIZE
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/* Assume that all systems that can run configure have sys/param.h. */
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# ifndef HAVE_SYS_PARAM_H
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# define HAVE_SYS_PARAM_H 1
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# endif
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# ifdef _SC_PAGESIZE
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# define getpagesize() sysconf(_SC_PAGESIZE)
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# else /* no _SC_PAGESIZE */
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# ifdef HAVE_SYS_PARAM_H
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# include <sys/param.h>
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# ifdef EXEC_PAGESIZE
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# define getpagesize() EXEC_PAGESIZE
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# else /* no EXEC_PAGESIZE */
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# ifdef NBPG
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# define getpagesize() NBPG * CLSIZE
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# ifndef CLSIZE
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# define CLSIZE 1
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# endif /* no CLSIZE */
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# else /* no NBPG */
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# ifdef NBPC
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# define getpagesize() NBPC
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# else /* no NBPC */
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# ifdef PAGESIZE
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# define getpagesize() PAGESIZE
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# endif /* PAGESIZE */
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# endif /* no NBPC */
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# endif /* no NBPG */
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# endif /* no EXEC_PAGESIZE */
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# else /* no HAVE_SYS_PARAM_H */
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# define getpagesize() 8192 /* punt totally */
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# endif /* no HAVE_SYS_PARAM_H */
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# endif /* no _SC_PAGESIZE */
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#endif /* no HAVE_GETPAGESIZE */
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int
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main ()
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{
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char *data, *data2, *data3;
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int i, pagesize;
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int fd;
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pagesize = getpagesize ();
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/* First, make a file with some known garbage in it. */
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data = (char *) malloc (pagesize);
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if (!data)
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return 1;
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for (i = 0; i < pagesize; ++i)
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*(data + i) = rand ();
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umask (0);
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fd = creat ("conftest.mmap", 0600);
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if (fd < 0)
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return 1;
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if (write (fd, data, pagesize) != pagesize)
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return 1;
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close (fd);
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/* Next, try to mmap the file at a fixed address which already has
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something else allocated at it. If we can, also make sure that
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we see the same garbage. */
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fd = open ("conftest.mmap", O_RDWR);
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if (fd < 0)
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return 1;
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data2 = (char *) malloc (2 * pagesize);
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if (!data2)
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return 1;
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data2 += (pagesize - ((long int) data2 & (pagesize - 1))) & (pagesize - 1);
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if (data2 != mmap (data2, pagesize, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_FIXED, fd, 0L))
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return 1;
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for (i = 0; i < pagesize; ++i)
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if (*(data + i) != *(data2 + i))
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return 1;
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/* Finally, make sure that changes to the mapped area do not
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percolate back to the file as seen by read(). (This is a bug on
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some variants of i386 svr4.0.) */
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for (i = 0; i < pagesize; ++i)
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*(data2 + i) = *(data2 + i) + 1;
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data3 = (char *) malloc (pagesize);
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if (!data3)
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return 1;
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if (read (fd, data3, pagesize) != pagesize)
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return 1;
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for (i = 0; i < pagesize; ++i)
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if (*(data + i) != *(data3 + i))
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return 1;
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close (fd);
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return 0;
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}
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_ACEOF
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if ac_fn_c_try_run "$LINENO"; then :
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ac_cv_func_mmap_fixed_mapped=yes
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else
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ac_cv_func_mmap_fixed_mapped=no
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fi
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rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
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conftest.$ac_objext conftest.beam conftest.$ac_ext
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fi
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fi
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{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_func_mmap_fixed_mapped" >&5
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$as_echo "$ac_cv_func_mmap_fixed_mapped" >&6; }
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if test $ac_cv_func_mmap_fixed_mapped = yes; then
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$as_echo "#define HAVE_MMAP 1" >>confdefs.h
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fi
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rm -f conftest.mmap
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{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing dlopen" >&5
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$as_echo_n "checking for library containing dlopen... " >&6; }
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if test "${ac_cv_search_dlopen+set}" = set; then :
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