Test on solib load and unload

This patch is to add a test case to on the performance of GDB handling
load and unload of shared library.

In V4:

 - Handle malloc and dlopen failure,
 - Document test parameters.

In V3, there are some changes,

 - Adapt to perf test framework changes.
 - Measure load and unload separately.

In V2, there are some changes,

 - A new proc gdb_produce_source to produce source files.  I tried to
   move all source file generation code out of solib.exp, but
   compilation step still needs to know the generated file names.  I
   have to hard-code the file names in compilation step, which is not
   good to me, so I give up on this moving.
 - SOLIB_NUMBER -> SOLIB_COUNT
 - New variable SOLIB_DLCLOSE_REVERSED_ORDER to control the order of
   iterating a list of shared libs to dlclose them.
 - New variable GDB_PERFORMANCE to enable these perf test cases.
 - Remove dlsym call in solib.c.
 - Update solib.py for the updated framework.

gdb/testsuite/

	* lib/gdb.exp (gdb_produce_source): New procedure.
	* gdb.perf/solib.c: New.
	* gdb.perf/solib.exp: New.
	* gdb.perf/solib.py: New.

gdb/testsuite/ChangeLog

@@ -1,3 +1,10 @@
+2013-11-06  Yao Qi  <yao@codesourcery.com>
+
+	* lib/gdb.exp (gdb_produce_source): New procedure.
+	* gdb.perf/solib.c: New.
+	* gdb.perf/solib.exp: New.
+	* gdb.perf/solib.py: New.
+
 2013-11-06  Yao Qi  <yao@codesourcery.com>
 
 	* README: Mention performance tests.

gdb/testsuite/gdb.perf/solib.c

@@ -0,0 +1,83 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifdef __WIN32__
+#include <windows.h>
+#define dlopen(name, mode) LoadLibrary (TEXT (name))
+# define dlsym(handle, func) GetProcAddress (handle, func)
+#define dlclose(handle) FreeLibrary (handle)
+#else
+#include <dlfcn.h>
+#endif
+
+static void **handles;
+
+void
+do_test_load (int number)
+{
+  char libname[40];
+  int i;
+
+  handles = malloc (sizeof (void *) * number);
+  if (handles == NULL)
+    {
+      printf ("ERROR on malloc\n");
+      exit (-1);
+    }
+
+  for (i = 0; i < number; i++)
+    {
+      sprintf (libname, "solib-lib%d", i);
+      handles[i] = dlopen (libname, RTLD_LAZY);
+      if (handles[i] == NULL)
+	{
+	  printf ("ERROR on dlopen %s\n", libname);
+	  exit (-1);
+	}
+    }
+}
+
+void
+do_test_unload (int number)
+{
+  int i;
+
+  /* Unload shared libraries in different orders.  */
+#ifndef SOLIB_DLCLOSE_REVERSED_ORDER
+  for (i = 0; i < number; i++)
+#else
+  for (i = number - 1; i >= 0; i--)
+#endif
+    dlclose (handles[i]);
+
+  free (handles);
+}
+
+static void
+end (void)
+{}
+
+int
+main (void)
+{
+  end ();
+
+  return 0;
+}

gdb/testsuite/gdb.perf/solib.exp

@@ -0,0 +1,87 @@
+# Copyright (C) 2013 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This test case is to test the performance of GDB when it is handling
+# the shared libraries of inferior are loaded and unloaded.
+# There are two parameters in this test:
+#  - SOLIB_COUNT is the number of shared libraries program will load
+#    and unload
+#  - SOLIB_DLCLOSE_REVERSED_ORDER controls the order of dlclose shared
+#    libraries.  If it is set, program dlclose shared libraries in a
+#    reversed order of loading.
+
+load_lib perftest.exp
+
+if [skip_perf_tests] {
+    return 0
+}
+
+standard_testfile .c
+set executable $testfile
+set expfile $testfile.exp
+
+# make check-perf RUNTESTFLAGS='solib.exp SOLIB_COUNT=1024'
+if ![info exists SOLIB_COUNT] {
+    set SOLIB_COUNT 128
+}
+
+PerfTest::assemble {
+    global SOLIB_COUNT
+    global srcdir subdir srcfile binfile
+
+    for {set i 0} {$i < $SOLIB_COUNT} {incr i} {
+
+	# Produce source files.
+	set libname "solib-lib$i"
+	set src [standard_output_file $libname.c]
+	set exe [standard_output_file $libname]
+
+	gdb_produce_source $src "int shr$i (void) {return 0;}"
+
+	# Compile.
+	if { [gdb_compile_shlib $src $exe {debug}] != "" } {
+	    return -1
+	}
+
+	# Delete object files to save some space.
+	file delete [standard_output_file  "solib-lib$i.c.o"]
+    }
+
+    set compile_flags {debug shlib_load}
+    global SOLIB_DLCLOSE_REVERSED_ORDER
+
+    if [info exists SOLIB_DLCLOSE_REVERSED_ORDER] {
+	lappend compile_flags "additional_flags=-DSOLIB_DLCLOSE_REVERSED_ORDER"
+    }
+
+    if { [gdb_compile "$srcdir/$subdir/$srcfile" ${binfile} executable  $compile_flags] != "" } {
+	return -1
+    }
+
+    return 0
+} {
+    global binfile
+
+    clean_restart $binfile
+
+    if ![runto_main] {
+	fail "Can't run to main"
+	return -1
+    }
+} {
+    global SOLIB_COUNT
+
+    gdb_test_no_output "python SolibLoadUnload\($SOLIB_COUNT\).run()"
+}

gdb/testsuite/gdb.perf/solib.py

@@ -0,0 +1,73 @@
+# Copyright (C) 2013 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This test case is to test the speed of GDB when it is handling the
+# shared libraries of inferior are loaded and unloaded.
+
+from perftest import perftest
+from perftest import measure
+
+class SolibLoadUnload1(perftest.TestCaseWithBasicMeasurements):
+    def __init__(self, solib_count, measure_load):
+        if measure_load:
+            name = "solib_load"
+        else:
+            name = "solib_unload"
+        # We want to measure time in this test.
+        super (SolibLoadUnload1, self).__init__ (name)
+        self.solib_count = solib_count
+        self.measure_load = measure_load
+
+    def warm_up(self):
+        do_test_load = "call do_test_load (%d)" % self.solib_count
+        do_test_unload = "call do_test_unload (%d)" % self.solib_count
+        gdb.execute(do_test_load)
+        gdb.execute(do_test_unload)
+
+    def execute_test(self):
+        num = self.solib_count
+        iteration = 5;
+
+        while num > 0 and iteration > 0:
+            # Do inferior calls to do_test_load and do_test_unload in pairs,
+            # but measure differently.
+            if self.measure_load:
+                do_test_load = "call do_test_load (%d)" % num
+                func = lambda: gdb.execute (do_test_load)
+
+                self.measure.measure(func, num)
+
+                do_test_unload = "call do_test_unload (%d)" % num
+                gdb.execute (do_test_unload)
+
+            else:
+                do_test_load = "call do_test_load (%d)" % num
+                gdb.execute (do_test_load)
+
+                do_test_unload = "call do_test_unload (%d)" % num
+                func = lambda: gdb.execute (do_test_unload)
+
+                self.measure.measure(func, num)
+
+            num = num / 2
+            iteration -= 1
+
+class SolibLoadUnload(object):
+    def __init__(self, solib_count):
+        self.solib_count = solib_count;
+
+    def run(self):
+        SolibLoadUnload1(self.solib_count, True).run()
+        SolibLoadUnload1(self.solib_count, False).run()

gdb/testsuite/lib/gdb.exp

@@ -1835,6 +1835,16 @@ gdb_caching_proc is_elf_target {
     return 1
 }
 
+# Produce source file NAME and write SOURCES into it.
+
+proc gdb_produce_source { name sources } {
+    set index 0
+    set f [open $name "w"]
+
+    puts $f $sources
+    close $f
+}
+
 # Return 1 if target is ILP32.
 # This cannot be decided simply from looking at the target string,
 # as it might depend on externally passed compiler options like -m64.