* [PATCH v2 2/3] Add a fast_hash function in common-utils
2019-10-08 16:09 [PATCH v2 0/3] Speed up hashing in demangled_names_hash Christian Biesinger via gdb-patches
@ 2019-10-08 16:09 ` Christian Biesinger via gdb-patches
2019-10-08 16:09 ` [PATCH v2 1/3] Store the mangled name as a string_view Christian Biesinger via gdb-patches
2019-10-08 16:09 ` [PATCH v2 3/3] Use libxxhash for hashing, if present Christian Biesinger via gdb-patches
2 siblings, 0 replies; 4+ messages in thread
From: Christian Biesinger via gdb-patches @ 2019-10-08 16:09 UTC (permalink / raw)
To: gdb-patches; +Cc: Christian Biesinger
Also updates a caller in symtab.c. For now this just calls htab_hash_string
but the next patch will change it to xxhash, if available.
gdb/ChangeLog:
2019-09-27 Christian Biesinger <cbiesinger@google.com>
* utils.c (fast_hash): New function.
* utils.h (fast_hash): New function.
* symtab.c (hash_demangled_name_entry): Call new function
fast_hash.
---
gdb/symtab.c | 3 ++-
gdb/utils.c | 6 ++++++
gdb/utils.h | 2 ++
3 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 0724110d12..2577f3909a 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -70,6 +70,7 @@
#include <algorithm>
#include "gdbsupport/gdb_string_view.h"
#include "gdbsupport/pathstuff.h"
+#include "gdbsupport/common-utils.h"
/* Forward declarations for local functions. */
@@ -727,7 +728,7 @@ hash_demangled_name_entry (const void *data)
const struct demangled_name_entry *e
= (const struct demangled_name_entry *) data;
- return iterative_hash (e->mangled.data (), e->mangled.length (), 0);
+ return fast_hash (e->mangled.data (), e->mangled.length ());
}
/* Equality function for the demangled name hash. */
diff --git a/gdb/utils.c b/gdb/utils.c
index e685cc2084..8615820c46 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -3436,6 +3436,12 @@ copy_bitwise (gdb_byte *dest, ULONGEST dest_offset,
}
}
+unsigned int
+fast_hash (const char* str, size_t len)
+{
+ return iterative_hash (str, len, 0);
+}
+
void
_initialize_utils (void)
{
diff --git a/gdb/utils.h b/gdb/utils.h
index 76f0da69f7..7101add394 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -569,4 +569,6 @@ extern void copy_bitwise (gdb_byte *dest, ULONGEST dest_offset,
const gdb_byte *source, ULONGEST source_offset,
ULONGEST nbits, int bits_big_endian);
+extern unsigned int fast_hash (const char* str, size_t len);
+
#endif /* UTILS_H */
--
2.23.0.581.g78d2f28ef7-goog
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v2 1/3] Store the mangled name as a string_view
2019-10-08 16:09 [PATCH v2 0/3] Speed up hashing in demangled_names_hash Christian Biesinger via gdb-patches
2019-10-08 16:09 ` [PATCH v2 2/3] Add a fast_hash function in common-utils Christian Biesinger via gdb-patches
@ 2019-10-08 16:09 ` Christian Biesinger via gdb-patches
2019-10-08 16:09 ` [PATCH v2 3/3] Use libxxhash for hashing, if present Christian Biesinger via gdb-patches
2 siblings, 0 replies; 4+ messages in thread
From: Christian Biesinger via gdb-patches @ 2019-10-08 16:09 UTC (permalink / raw)
To: gdb-patches; +Cc: Christian Biesinger
This should be a bit faster (because we can compare the size first),
but it is also a dependency for the next patch.
(3.47% of gdb startup time is spent in eq_demangled_name_entry when
attaching to Chrome's content_shell binary)
gdb/ChangeLog:
2019-09-27 Christian Biesinger <cbiesinger@google.com>
* symtab.c (struct demangled_name_entry): Change type of mangled
to gdb::string_view.
(hash_demangled_name_entry): Update.
(eq_demangled_name_entry): Update.
(symbol_set_names): Update.
---
gdb/symtab.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 8a551f1575..0724110d12 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -68,6 +68,7 @@
#include "filename-seen-cache.h"
#include "arch-utils.h"
#include <algorithm>
+#include "gdbsupport/gdb_string_view.h"
#include "gdbsupport/pathstuff.h"
/* Forward declarations for local functions. */
@@ -713,7 +714,7 @@ symbol_set_language (struct general_symbol_info *gsymbol,
/* Objects of this type are stored in the demangled name hash table. */
struct demangled_name_entry
{
- const char *mangled;
+ gdb::string_view mangled;
ENUM_BITFIELD(language) language : LANGUAGE_BITS;
char demangled[1];
};
@@ -726,7 +727,7 @@ hash_demangled_name_entry (const void *data)
const struct demangled_name_entry *e
= (const struct demangled_name_entry *) data;
- return htab_hash_string (e->mangled);
+ return iterative_hash (e->mangled.data (), e->mangled.length (), 0);
}
/* Equality function for the demangled name hash. */
@@ -739,7 +740,7 @@ eq_demangled_name_entry (const void *a, const void *b)
const struct demangled_name_entry *db
= (const struct demangled_name_entry *) b;
- return strcmp (da->mangled, db->mangled) == 0;
+ return da->mangled == db->mangled;
}
/* Create the hash table used for demangled names. Each hash entry is
@@ -855,7 +856,7 @@ symbol_set_names (struct general_symbol_info *gsymbol,
else
linkage_name_copy = linkage_name;
- entry.mangled = linkage_name_copy;
+ entry.mangled = gdb::string_view (linkage_name_copy, len);
slot = ((struct demangled_name_entry **)
htab_find_slot (per_bfd->demangled_names_hash.get (),
&entry, INSERT));
@@ -888,7 +889,7 @@ symbol_set_names (struct general_symbol_info *gsymbol,
obstack_alloc (&per_bfd->storage_obstack,
offsetof (struct demangled_name_entry, demangled)
+ demangled_len + 1));
- (*slot)->mangled = linkage_name;
+ (*slot)->mangled = gdb::string_view (linkage_name, len);
}
else
{
@@ -904,7 +905,7 @@ symbol_set_names (struct general_symbol_info *gsymbol,
+ len + demangled_len + 2));
mangled_ptr = &((*slot)->demangled[demangled_len + 1]);
strcpy (mangled_ptr, linkage_name_copy);
- (*slot)->mangled = mangled_ptr;
+ (*slot)->mangled = gdb::string_view (mangled_ptr, len);
}
(*slot)->language = gsymbol->language;
@@ -917,7 +918,7 @@ symbol_set_names (struct general_symbol_info *gsymbol,
|| gsymbol->language == language_auto)
gsymbol->language = (*slot)->language;
- gsymbol->name = (*slot)->mangled;
+ gsymbol->name = (*slot)->mangled.data ();
if ((*slot)->demangled[0] != '\0')
symbol_set_demangled_name (gsymbol, (*slot)->demangled,
&per_bfd->storage_obstack);
--
2.23.0.581.g78d2f28ef7-goog
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v2 3/3] Use libxxhash for hashing, if present
2019-10-08 16:09 [PATCH v2 0/3] Speed up hashing in demangled_names_hash Christian Biesinger via gdb-patches
2019-10-08 16:09 ` [PATCH v2 2/3] Add a fast_hash function in common-utils Christian Biesinger via gdb-patches
2019-10-08 16:09 ` [PATCH v2 1/3] Store the mangled name as a string_view Christian Biesinger via gdb-patches
@ 2019-10-08 16:09 ` Christian Biesinger via gdb-patches
2 siblings, 0 replies; 4+ messages in thread
From: Christian Biesinger via gdb-patches @ 2019-10-08 16:09 UTC (permalink / raw)
To: gdb-patches; +Cc: Christian Biesinger
XXHash is faster than htab_hash_string:
------------------------------------------------------------
Benchmark Time CPU Iterations
------------------------------------------------------------
BM_xxh3 11 ns 11 ns 65887249
BM_xxh32 19 ns 19 ns 36511877
BM_hash_string 182 ns 182 ns 3853125
BM_iterative_hash 77 ns 77 ns 9087638
Unfortunately, XXH3 is still experimental (see
https://github.com/Cyan4973/xxHash#user-content-new-experimental-hash-algorithm)
However, regular XXH32 is still a lot faster than
htab_hash_string per my benchmark above. I used the
following string for the benchmark:
static constexpr char str[] = "_ZZZL13make_gdb_typeP7gdbarchP10tdesc_typeEN16gdb_type_creator19make_gdb_type_flagsEPK22tdesc_type_with_fieldsE19__PRETTY_FUNCTION__";
htab_hash_string is currently 4.35% + 7.98% (rehashing) of gdb
startup when attaching to Chrome's content_shell.
An additional 5.21% is spent in msymbol_hash, which does not use
this hash function. Unfortunately, since it has to lowercase the
string, it can't use this hash function.
BM_msymbol_hash 52 ns 52 ns 13281495
It may be worth investigating if strlen+XXHash is still faster than
htab_hash_string, which would make it easier to use in more places.
Debian ships xxhash as libxxhash{0,-dev}. Fedora ships it as xxhash-devel.
gdb/ChangeLog:
2019-09-27 Christian Biesinger <cbiesinger@google.com>
* Makefile.in: Link with libxxhash.
* config.in: Regenerate.
* configure: Regenerate.
* configure.ac: Search for libxxhash.
* utils.c (fast_hash): Use xxhash if present.
---
gdb/Makefile.in | 8 +-
gdb/config.in | 3 +
gdb/configure | 493 +++++++++++++++++++++++++++++++++++++++++++++++
gdb/configure.ac | 19 ++
gdb/utils.c | 8 +
5 files changed, 529 insertions(+), 2 deletions(-)
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 36650ad555..7b3c46cf8e 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -187,10 +187,14 @@ LIBEXPAT = @LIBEXPAT@
# Where is lzma? This will be empty if lzma was not available.
LIBLZMA = @LIBLZMA@
-# Where is libbabeltrace? This will be empty if lbabeltrace was not
+# Where is libbabeltrace? This will be empty if libbabeltrace was not
# available.
LIBBABELTRACE = @LIBBABELTRACE@
+# Where is libxxhash? This will be empty if libxxhash was not
+# available.
+LIBXXHASH = @LIBXXHASH@
+
# Where is libipt? This will be empty if libipt was not available.
LIBIPT = @LIBIPT@
@@ -597,7 +601,7 @@ CLIBS = $(SIM) $(READLINE) $(OPCODES) $(BFD) $(LIBCTF) $(ZLIB) \
@LIBS@ @GUILE_LIBS@ @PYTHON_LIBS@ \
$(LIBEXPAT) $(LIBLZMA) $(LIBBABELTRACE) $(LIBIPT) \
$(LIBIBERTY) $(WIN32LIBS) $(LIBGNU) $(LIBICONV) $(LIBMPFR) \
- $(SRCHIGH_LIBS)
+ $(SRCHIGH_LIBS) $(LIBXXHASH)
CDEPS = $(NAT_CDEPS) $(SIM) $(BFD) $(READLINE_DEPS) $(LIBCTF) \
$(OPCODES) $(INTL_DEPS) $(LIBIBERTY) $(CONFIG_DEPS) $(LIBGNU)
diff --git a/gdb/config.in b/gdb/config.in
index 26ca02f6a3..da365a7fc8 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -255,6 +255,9 @@
/* Define to 1 if you have the <libunwind-ia64.h> header file. */
#undef HAVE_LIBUNWIND_IA64_H
+/* Define if you have the xxhash library. */
+#undef HAVE_LIBXXHASH
+
/* Define to 1 if you have the <linux/elf.h> header file. */
#undef HAVE_LINUX_ELF_H
diff --git a/gdb/configure b/gdb/configure
index 22a5f6051d..acad7acb5c 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -627,6 +627,9 @@ GCORE_TRANSFORM_NAME
GDB_TRANSFORM_NAME
XSLTPROC
GDB_NM_FILE
+LTLIBXXHASH
+LIBXXHASH
+HAVE_LIBXXHASH
LTLIBBABELTRACE
LIBBABELTRACE
HAVE_LIBBABELTRACE
@@ -897,6 +900,8 @@ enable_sim
enable_gdbserver
with_babeltrace
with_libbabeltrace_prefix
+with_xxhash
+with_libxxhash_prefix
enable_unit_tests
'
ac_precious_vars='build_alias
@@ -1627,6 +1632,9 @@ Optional Packages:
--with-babeltrace include babeltrace support (auto/yes/no)
--with-libbabeltrace-prefix[=DIR] search for libbabeltrace in DIR/include and DIR/lib
--without-libbabeltrace-prefix don't search for libbabeltrace in includedir and libdir
+ --with-xxhash use libxxhash for hashing (faster) (auto/yes/no)
+ --with-libxxhash-prefix[=DIR] search for libxxhash in DIR/include and DIR/lib
+ --without-libxxhash-prefix don't search for libxxhash in includedir and libdir
Some influential environment variables:
CC C compiler command
@@ -17556,6 +17564,491 @@ $as_echo "$as_me: WARNING: babeltrace is missing or unusable; GDB is unable to r
fi
fi
+# Check for xxhash
+
+# Check whether --with-xxhash was given.
+if test "${with_xxhash+set}" = set; then :
+ withval=$with_xxhash;
+else
+ with_xxhash=auto
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to use xxhash" >&5
+$as_echo_n "checking whether to use xxhash... " >&6; }
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_xxhash" >&5
+$as_echo "$with_xxhash" >&6; }
+
+if test "x$with_xxhash" != "xno"; then
+
+
+
+
+
+
+
+
+ use_additional=yes
+
+ acl_save_prefix="$prefix"
+ prefix="$acl_final_prefix"
+ acl_save_exec_prefix="$exec_prefix"
+ exec_prefix="$acl_final_exec_prefix"
+
+ eval additional_includedir=\"$includedir\"
+ eval additional_libdir=\"$libdir\"
+
+ exec_prefix="$acl_save_exec_prefix"
+ prefix="$acl_save_prefix"
+
+
+# Check whether --with-libxxhash-prefix was given.
+if test "${with_libxxhash_prefix+set}" = set; then :
+ withval=$with_libxxhash_prefix;
+ if test "X$withval" = "Xno"; then
+ use_additional=no
+ else
+ if test "X$withval" = "X"; then
+
+ acl_save_prefix="$prefix"
+ prefix="$acl_final_prefix"
+ acl_save_exec_prefix="$exec_prefix"
+ exec_prefix="$acl_final_exec_prefix"
+
+ eval additional_includedir=\"$includedir\"
+ eval additional_libdir=\"$libdir\"
+
+ exec_prefix="$acl_save_exec_prefix"
+ prefix="$acl_save_prefix"
+
+ else
+ additional_includedir="$withval/include"
+ additional_libdir="$withval/lib"
+ fi
+ fi
+
+fi
+
+ LIBXXHASH=
+ LTLIBXXHASH=
+ INCXXHASH=
+ rpathdirs=
+ ltrpathdirs=
+ names_already_handled=
+ names_next_round='xxhash '
+ while test -n "$names_next_round"; do
+ names_this_round="$names_next_round"
+ names_next_round=
+ for name in $names_this_round; do
+ already_handled=
+ for n in $names_already_handled; do
+ if test "$n" = "$name"; then
+ already_handled=yes
+ break
+ fi
+ done
+ if test -z "$already_handled"; then
+ names_already_handled="$names_already_handled $name"
+ uppername=`echo "$name" | sed -e 'y|abcdefghijklmnopqrstuvwxyz./-|ABCDEFGHIJKLMNOPQRSTUVWXYZ___|'`
+ eval value=\"\$HAVE_LIB$uppername\"
+ if test -n "$value"; then
+ if test "$value" = yes; then
+ eval value=\"\$LIB$uppername\"
+ test -z "$value" || LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$value"
+ eval value=\"\$LTLIB$uppername\"
+ test -z "$value" || LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }$value"
+ else
+ :
+ fi
+ else
+ found_dir=
+ found_la=
+ found_so=
+ found_a=
+ if test $use_additional = yes; then
+ if test -n "$shlibext" && test -f "$additional_libdir/lib$name.$shlibext"; then
+ found_dir="$additional_libdir"
+ found_so="$additional_libdir/lib$name.$shlibext"
+ if test -f "$additional_libdir/lib$name.la"; then
+ found_la="$additional_libdir/lib$name.la"
+ fi
+ else
+ if test -f "$additional_libdir/lib$name.$libext"; then
+ found_dir="$additional_libdir"
+ found_a="$additional_libdir/lib$name.$libext"
+ if test -f "$additional_libdir/lib$name.la"; then
+ found_la="$additional_libdir/lib$name.la"
+ fi
+ fi
+ fi
+ fi
+ if test "X$found_dir" = "X"; then
+ for x in $LDFLAGS $LTLIBXXHASH; do
+
+ acl_save_prefix="$prefix"
+ prefix="$acl_final_prefix"
+ acl_save_exec_prefix="$exec_prefix"
+ exec_prefix="$acl_final_exec_prefix"
+ eval x=\"$x\"
+ exec_prefix="$acl_save_exec_prefix"
+ prefix="$acl_save_prefix"
+
+ case "$x" in
+ -L*)
+ dir=`echo "X$x" | sed -e 's/^X-L//'`
+ if test -n "$shlibext" && test -f "$dir/lib$name.$shlibext"; then
+ found_dir="$dir"
+ found_so="$dir/lib$name.$shlibext"
+ if test -f "$dir/lib$name.la"; then
+ found_la="$dir/lib$name.la"
+ fi
+ else
+ if test -f "$dir/lib$name.$libext"; then
+ found_dir="$dir"
+ found_a="$dir/lib$name.$libext"
+ if test -f "$dir/lib$name.la"; then
+ found_la="$dir/lib$name.la"
+ fi
+ fi
+ fi
+ ;;
+ esac
+ if test "X$found_dir" != "X"; then
+ break
+ fi
+ done
+ fi
+ if test "X$found_dir" != "X"; then
+ LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }-L$found_dir -l$name"
+ if test "X$found_so" != "X"; then
+ if test "$enable_rpath" = no || test "X$found_dir" = "X/usr/lib"; then
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_so"
+ else
+ haveit=
+ for x in $ltrpathdirs; do
+ if test "X$x" = "X$found_dir"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ ltrpathdirs="$ltrpathdirs $found_dir"
+ fi
+ if test "$hardcode_direct" = yes; then
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_so"
+ else
+ if test -n "$hardcode_libdir_flag_spec" && test "$hardcode_minus_L" = no; then
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_so"
+ haveit=
+ for x in $rpathdirs; do
+ if test "X$x" = "X$found_dir"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ rpathdirs="$rpathdirs $found_dir"
+ fi
+ else
+ haveit=
+ for x in $LDFLAGS $LIBXXHASH; do
+
+ acl_save_prefix="$prefix"
+ prefix="$acl_final_prefix"
+ acl_save_exec_prefix="$exec_prefix"
+ exec_prefix="$acl_final_exec_prefix"
+ eval x=\"$x\"
+ exec_prefix="$acl_save_exec_prefix"
+ prefix="$acl_save_prefix"
+
+ if test "X$x" = "X-L$found_dir"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-L$found_dir"
+ fi
+ if test "$hardcode_minus_L" != no; then
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_so"
+ else
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-l$name"
+ fi
+ fi
+ fi
+ fi
+ else
+ if test "X$found_a" != "X"; then
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_a"
+ else
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-L$found_dir -l$name"
+ fi
+ fi
+ additional_includedir=
+ case "$found_dir" in
+ */lib | */lib/)
+ basedir=`echo "X$found_dir" | sed -e 's,^X,,' -e 's,/lib/*$,,'`
+ additional_includedir="$basedir/include"
+ ;;
+ esac
+ if test "X$additional_includedir" != "X"; then
+ if test "X$additional_includedir" != "X/usr/include"; then
+ haveit=
+ if test "X$additional_includedir" = "X/usr/local/include"; then
+ if test -n "$GCC"; then
+ case $host_os in
+ linux*) haveit=yes;;
+ esac
+ fi
+ fi
+ if test -z "$haveit"; then
+ for x in $CPPFLAGS $INCXXHASH; do
+
+ acl_save_prefix="$prefix"
+ prefix="$acl_final_prefix"
+ acl_save_exec_prefix="$exec_prefix"
+ exec_prefix="$acl_final_exec_prefix"
+ eval x=\"$x\"
+ exec_prefix="$acl_save_exec_prefix"
+ prefix="$acl_save_prefix"
+
+ if test "X$x" = "X-I$additional_includedir"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ if test -d "$additional_includedir"; then
+ INCXXHASH="${INCXXHASH}${INCXXHASH:+ }-I$additional_includedir"
+ fi
+ fi
+ fi
+ fi
+ fi
+ if test -n "$found_la"; then
+ save_libdir="$libdir"
+ case "$found_la" in
+ */* | *\\*) . "$found_la" ;;
+ *) . "./$found_la" ;;
+ esac
+ libdir="$save_libdir"
+ for dep in $dependency_libs; do
+ case "$dep" in
+ -L*)
+ additional_libdir=`echo "X$dep" | sed -e 's/^X-L//'`
+ if test "X$additional_libdir" != "X/usr/lib"; then
+ haveit=
+ if test "X$additional_libdir" = "X/usr/local/lib"; then
+ if test -n "$GCC"; then
+ case $host_os in
+ linux*) haveit=yes;;
+ esac
+ fi
+ fi
+ if test -z "$haveit"; then
+ haveit=
+ for x in $LDFLAGS $LIBXXHASH; do
+
+ acl_save_prefix="$prefix"
+ prefix="$acl_final_prefix"
+ acl_save_exec_prefix="$exec_prefix"
+ exec_prefix="$acl_final_exec_prefix"
+ eval x=\"$x\"
+ exec_prefix="$acl_save_exec_prefix"
+ prefix="$acl_save_prefix"
+
+ if test "X$x" = "X-L$additional_libdir"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ if test -d "$additional_libdir"; then
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-L$additional_libdir"
+ fi
+ fi
+ haveit=
+ for x in $LDFLAGS $LTLIBXXHASH; do
+
+ acl_save_prefix="$prefix"
+ prefix="$acl_final_prefix"
+ acl_save_exec_prefix="$exec_prefix"
+ exec_prefix="$acl_final_exec_prefix"
+ eval x=\"$x\"
+ exec_prefix="$acl_save_exec_prefix"
+ prefix="$acl_save_prefix"
+
+ if test "X$x" = "X-L$additional_libdir"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ if test -d "$additional_libdir"; then
+ LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }-L$additional_libdir"
+ fi
+ fi
+ fi
+ fi
+ ;;
+ -R*)
+ dir=`echo "X$dep" | sed -e 's/^X-R//'`
+ if test "$enable_rpath" != no; then
+ haveit=
+ for x in $rpathdirs; do
+ if test "X$x" = "X$dir"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ rpathdirs="$rpathdirs $dir"
+ fi
+ haveit=
+ for x in $ltrpathdirs; do
+ if test "X$x" = "X$dir"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ ltrpathdirs="$ltrpathdirs $dir"
+ fi
+ fi
+ ;;
+ -l*)
+ names_next_round="$names_next_round "`echo "X$dep" | sed -e 's/^X-l//'`
+ ;;
+ *.la)
+ names_next_round="$names_next_round "`echo "X$dep" | sed -e 's,^X.*/,,' -e 's,^lib,,' -e 's,\.la$,,'`
+ ;;
+ *)
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$dep"
+ LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }$dep"
+ ;;
+ esac
+ done
+ fi
+ else
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-l$name"
+ LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }-l$name"
+ fi
+ fi
+ fi
+ done
+ done
+ if test "X$rpathdirs" != "X"; then
+ if test -n "$hardcode_libdir_separator"; then
+ alldirs=
+ for found_dir in $rpathdirs; do
+ alldirs="${alldirs}${alldirs:+$hardcode_libdir_separator}$found_dir"
+ done
+ acl_save_libdir="$libdir"
+ libdir="$alldirs"
+ eval flag=\"$hardcode_libdir_flag_spec\"
+ libdir="$acl_save_libdir"
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$flag"
+ else
+ for found_dir in $rpathdirs; do
+ acl_save_libdir="$libdir"
+ libdir="$found_dir"
+ eval flag=\"$hardcode_libdir_flag_spec\"
+ libdir="$acl_save_libdir"
+ LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$flag"
+ done
+ fi
+ fi
+ if test "X$ltrpathdirs" != "X"; then
+ for found_dir in $ltrpathdirs; do
+ LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }-R$found_dir"
+ done
+ fi
+
+
+ ac_save_CPPFLAGS="$CPPFLAGS"
+
+ for element in $INCXXHASH; do
+ haveit=
+ for x in $CPPFLAGS; do
+
+ acl_save_prefix="$prefix"
+ prefix="$acl_final_prefix"
+ acl_save_exec_prefix="$exec_prefix"
+ exec_prefix="$acl_final_exec_prefix"
+ eval x=\"$x\"
+ exec_prefix="$acl_save_exec_prefix"
+ prefix="$acl_save_prefix"
+
+ if test "X$x" = "X$element"; then
+ haveit=yes
+ break
+ fi
+ done
+ if test -z "$haveit"; then
+ CPPFLAGS="${CPPFLAGS}${CPPFLAGS:+ }$element"
+ fi
+ done
+
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for libxxhash" >&5
+$as_echo_n "checking for libxxhash... " >&6; }
+if ${ac_cv_libxxhash+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+
+ ac_save_LIBS="$LIBS"
+ LIBS="$LIBS $LIBXXHASH"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+#include <xxhash.h>
+int
+main ()
+{
+XXH32("foo", 3, 0);
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ ac_cv_libxxhash=yes
+else
+ ac_cv_libxxhash=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+ LIBS="$ac_save_LIBS"
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_libxxhash" >&5
+$as_echo "$ac_cv_libxxhash" >&6; }
+ if test "$ac_cv_libxxhash" = yes; then
+ HAVE_LIBXXHASH=yes
+
+$as_echo "#define HAVE_LIBXXHASH 1" >>confdefs.h
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking how to link with libxxhash" >&5
+$as_echo_n "checking how to link with libxxhash... " >&6; }
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $LIBXXHASH" >&5
+$as_echo "$LIBXXHASH" >&6; }
+ else
+ HAVE_LIBXXHASH=no
+ CPPFLAGS="$ac_save_CPPFLAGS"
+ LIBXXHASH=
+ LTLIBXXHASH=
+ fi
+
+
+
+
+
+
+ if test "$HAVE_XXHASH" != yes; then
+ if test "$with_xxhash" = yes; then
+ as_fn_error $? "xxhash is missing or unusable" "$LINENO" 5
+ fi
+ fi
+fi
+
# If nativefile (NAT_FILE) is not set in configure.nat, we link to an
# empty version.
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 9da8818fb5..7a2a5ca9d4 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -2217,6 +2217,25 @@ else
fi
fi
+# Check for xxhash
+AC_ARG_WITH(xxhash,
+ AC_HELP_STRING([--with-xxhash], [use libxxhash for hashing (faster) (auto/yes/no)]),
+ [], [with_xxhash=auto])
+AC_MSG_CHECKING([whether to use xxhash])
+AC_MSG_RESULT([$with_xxhash])
+
+if test "x$with_xxhash" != "xno"; then
+ AC_LIB_HAVE_LINKFLAGS([xxhash], [],
+ [#include <xxhash.h>],
+ [XXH32("foo", 3, 0);
+ ])
+ if test "$HAVE_XXHASH" != yes; then
+ if test "$with_xxhash" = yes; then
+ AC_MSG_ERROR([xxhash is missing or unusable])
+ fi
+ fi
+fi
+
# If nativefile (NAT_FILE) is not set in configure.nat, we link to an
# empty version.
diff --git a/gdb/utils.c b/gdb/utils.c
index 8615820c46..a0b546342b 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -36,6 +36,10 @@
#include <pc.h>
#endif
+#ifdef HAVE_LIBXXHASH
+#include <xxhash.h>
+#endif
+
#include <signal.h>
#include "gdbcmd.h"
#include "serial.h"
@@ -3439,7 +3443,11 @@ copy_bitwise (gdb_byte *dest, ULONGEST dest_offset,
unsigned int
fast_hash (const char* str, size_t len)
{
+#ifdef HAVE_LIBXXHASH
+ return XXH32(str, len, 0);
+#else
return iterative_hash (str, len, 0);
+#endif
}
void
--
2.23.0.581.g78d2f28ef7-goog
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