+2011-10-10 Aldy Hernandez <aldyh@redhat.com>
+
+ * lib/gcc-simulate-thread.exp: New.
+ * gcc.dg/simulate-thread/guality.h: New.
+ * gcc.dg/simulate-thread/simulate-thread.h: New.
+ * gcc.dg/simulate-thread/simulate-thread.exp: New.
+ * gcc.dg/simulate-thread/simulate-thread.gdb: New.
+ * gcc.dg/simulate-thread/README: New.
+ * g++.dg/simulate-thread/guality.h: New.
+ * g++.dg/simulate-thread/simulate-thread.h: New.
+ * g++.dg/simulate-thread/simulate-thread.exp: New.
+ * g++.dg/simulate-thread/simulate-thread.gdb: New.
+ * c-c++-common/cxxbitfields-2.c: Remove.
+ * c-c++-common/cxxbitfields.c: Remove.
+ * c-c++-common/cxxbitfields-4.c: Remove.
+ * c-c++-common/cxxbitfields-5.c: Remove.
+ * c-c++-common/simulate-thread/bitfields-1.c: New.
+ * c-c++-common/simulate-thread/bitfields-2.c: New.
+ * c-c++-common/simulate-thread/bitfields-3.c: New.
+ * c-c++-common/simulate-thread/bitfields-4.c: New.
+
2011-10-09 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/38980
+++ /dev/null
-/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
-/* { dg-options "-O2 --param allow-store-data-races=0" } */
-
-/* Test that we don't store past VAR.K. */
-
-struct S
-{
- volatile int i;
- volatile int j: 32;
- volatile int k: 15;
- volatile char c[2];
-} var;
-
-void setit()
-{
- var.k = 13;
-}
-
-/* { dg-final { scan-assembler-not "movl.*, var" } } */
+++ /dev/null
-/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
-/* { dg-options "-O2 --param allow-store-data-races=0" } */
-
-struct bits
-{
- char a;
- int b:7;
- int c:9;
- unsigned char d;
-} x;
-
-/* Store into <c> should not clobber <d>. */
-void update_c(struct bits *p, int val)
-{
- p -> c = val;
-}
-
-/* { dg-final { scan-assembler "mov\[bw\]" } } */
+++ /dev/null
-/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
-/* { dg-options "-O2 --param allow-store-data-races=0" } */
-
-#include <stdlib.h>
-
-struct bits
-{
- char a;
- int b:7;
- int c:9;
- unsigned char d;
-} x;
-
-struct bits *p;
-
-static void allocit()
-{
- p = (struct bits *) malloc (sizeof (struct bits));
-}
-
-/* Store into <c> should not clobber <d>. */
-/* We should not use a 32-bit move to store into p->, but a smaller move. */
-void foo()
-{
- allocit();
- p -> c = 55;
-}
-
-/* { dg-final { scan-assembler "mov\[bw\]" } } */
+++ /dev/null
-/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
-/* { dg-options "-O2 --param allow-store-data-races=0" } */
-
-/* Test that we don't store past VAR.A. */
-
-struct S
-{
- volatile unsigned int a : 4;
- unsigned char b;
- unsigned int c : 6;
-} var;
-
-void set_a()
-{
- var.a = 12;
-}
-
-/* { dg-final { scan-assembler-not "movl.*, var" } } */
--- /dev/null
+/* { dg-do link } */
+/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-final { simulate-thread } } */
+
+#include <stdio.h>
+#include "../../gcc.dg/simulate-thread/simulate-thread.h"
+
+/* Test that we don't store past VAR.A. */
+
+struct S
+{
+ volatile unsigned int a : 4;
+ unsigned char b;
+ unsigned int c : 6;
+} var = { 1, 2, 3 };
+
+static int global = 0;
+
+/* Called before each instruction, simulating another thread
+ executing. */
+void simulate_thread_other_threads()
+{
+ global++;
+ var.b = global;
+ /* Don't go past the 6 bits var.c can hold. */
+ var.c = global % 64;
+}
+
+/* Called after each instruction. Returns 1 if any inconsistency is
+ found, 0 otherwise. */
+int simulate_thread_step_verify()
+{
+ int ret = 0;
+ if (var.b != global)
+ {
+ printf("FAIL: invalid intermediate value for <b>.\n");
+ ret = 1;
+ }
+ if (var.c != global % 64)
+ {
+ printf("FAIL: invalid intermediate value for <c>.\n");
+ ret = 1;
+ }
+ return ret;
+}
+
+/* Called at the end of the program (simulate_thread_fini == 1). Verifies
+ the state of the program and returns 1 if any inconsistency is
+ found, 0 otherwise. */
+int simulate_thread_final_verify()
+{
+ if (var.a != 12)
+ {
+ printf("FAIL: invalid final result for <a>.\n");
+ return 1;
+ }
+ return 0;
+}
+
+__attribute__((noinline))
+void simulate_thread_main()
+{
+ var.a = 12;
+}
+
+int main()
+{
+ simulate_thread_main();
+ simulate_thread_done();
+ return 0;
+}
--- /dev/null
+/* { dg-do link } */
+/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-final { simulate-thread } } */
+
+#include <stdio.h>
+#include "../../gcc.dg/simulate-thread/simulate-thread.h"
+
+/* Test that we don't store past VAR.K. */
+
+struct S
+{
+ volatile int i;
+ volatile int j: 32;
+ volatile int k: 15;
+ volatile unsigned char c[2];
+} var;
+
+static int global = 0;
+
+void simulate_thread_other_threads()
+{
+ global++;
+ var.c[0] = global % 256;
+ var.c[1] = global % 256;
+}
+
+int simulate_thread_step_verify()
+{
+ if (var.c[0] != global % 256
+ || var.c[1] != global % 256)
+ {
+ printf("FAIL: invalid intermediate result for <var.c[]>.\n");
+ return 1;
+ }
+ return 0;
+}
+
+int simulate_thread_final_verify()
+{
+ if (var.k != 13)
+ {
+ printf("FAIL: invalid final result\n");
+ return 1;
+ }
+ return 0;
+}
+
+__attribute__((noinline))
+void simulate_thread_main()
+{
+ var.k = 13;
+}
+
+int main()
+{
+ simulate_thread_main();
+ simulate_thread_done();
+ return 0;
+}
--- /dev/null
+/* { dg-do link } */
+/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-final { simulate-thread } } */
+
+#include <stdio.h>
+#include "../../gcc.dg/simulate-thread/simulate-thread.h"
+
+/* Store into <c> should not clobber <d>. */
+
+struct bits
+{
+ char a;
+ int b:7;
+ int c:9;
+ unsigned char d;
+} var;
+
+static int global = 0;
+
+void simulate_thread_other_threads()
+{
+ global++;
+ var.d = global;
+}
+
+int simulate_thread_step_verify()
+{
+ if (var.d != global)
+ {
+ printf("FAIL: invalid intermediate result\n");
+ return 1;
+ }
+ return 0;
+}
+
+int simulate_thread_final_verify()
+{
+ if (var.c != 5)
+ {
+ printf("FAIL: invalid final result\n");
+ return 1;
+ }
+ return 0;
+}
+
+__attribute__((noinline))
+void update_c(struct bits *p, int val)
+{
+ p -> c = val;
+}
+
+__attribute__((noinline))
+void simulate_thread_main()
+{
+ update_c(&var, 5);
+}
+
+int main()
+{
+ simulate_thread_main();
+ simulate_thread_done();
+ return 0;
+}
--- /dev/null
+/* { dg-do link } */
+/* { dg-options "--param allow-store-data-races=0" } */
+/* { dg-final { simulate-thread } } */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "../../gcc.dg/simulate-thread/simulate-thread.h"
+
+struct bits
+{
+ char a;
+ int b:7;
+ int c:9;
+ unsigned char d;
+} *p;
+
+static int global = 0;
+
+void simulate_thread_other_threads()
+{
+ global++;
+ p->d = global % 256;
+}
+
+int simulate_thread_step_verify()
+{
+ if (p->d != global % 256)
+ {
+ printf("FAIL: invalid intermediate result\n");
+ return 1;
+ }
+ return 0;
+}
+
+int simulate_thread_final_verify()
+{
+ if (p->c != 55)
+ {
+ printf("FAIL: invalid final result\n");
+ return 1;
+ }
+ return 0;
+}
+
+/* Store into <c> should not clobber <d>. */
+/* We should not use a 32-bit move to store into p->, but a smaller move. */
+__attribute__((noinline))
+void simulate_thread_main()
+{
+ p -> c = 55;
+}
+
+
+int main()
+{
+ p = (struct bits *) calloc (1, sizeof (struct bits));
+ simulate_thread_main();
+ simulate_thread_done();
+ return 0;
+}
--- /dev/null
+# Copyright (C) 2011 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 GCC; see the file COPYING3. If not see
+# <http://www.gnu.org/licenses/>.
+
+
+# Your run of the mill dg test, but verify that we have a working GDB first.
+
+load_lib g++-dg.exp
+load_lib gcc-simulate-thread.exp
+load_lib torture-options.exp
+
+dg-init
+torture-init
+set-torture-options [list \
+ { -O0 -g } \
+ { -O1 -g } \
+ { -O2 -g } \
+ { -O3 -g } \
+ { -Os -g } ]
+
+if [gdb-exists] {
+ gcc-dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.C]] ""
+ gcc-dg-runtest [lsort [glob $srcdir/c-c++-common/simulate-thread/*.c]] ""
+}
+
+torture-finish
+dg-finish
--- /dev/null
+source ../../gcc.dg/simulate-thread/simulate-thread.gdb
--- /dev/null
+#include "../../gcc.dg/simulate-thread/simulate-thread.h"
--- /dev/null
+OVERVIEW
+--------
+
+This is a harness to test the atomicity of certain operations, and to
+make sure the compiler does not introduce data races in a
+multi-threaded environment.
+
+The basic premise is that we set up testcases such that the thing we
+want test, say an atomic instruction which stores a double word is in
+a function of its own. We then run this testcase within GDB,
+controlled by a gdb script (simulate-thread.gdb). The gdb script will
+break on the function to be tested, and then single step through every
+machine instruction in the function. We set this up so GDB can make a
+couple of inferior function calls before and after each of these
+single step instructions for a couple of purposes:
+
+ 1. One of the calls simulates another thread running in the
+ process which changes or access memory.
+
+ 2. The other calls are used to verify that we always get the
+ expected behavior.
+
+For example, in the case of an atomic store, anyone looking at the
+memory associated with an atomic variable should never see any in
+between states. If you have an atomic long long int, and it starts
+with the value 0, and you write the value MAX_LONG_LONG, any other
+thread looking at that variable should never see anything other than 0
+or MAX_LONG_LONG. If you implement the atomic write as a sequence of
+2 stores, it is possible for another thread to read the location after
+the first store, but before the second one is complete. That thread
+would then see an in-between state (one word would still be 0).
+
+We simulate this in the testcase by having GDB step through the
+program, instruction by instruction, and after each step, making an
+inferior function call which looks at the value of the atomic variable
+and verifies that it sees either 0 or MAX_LONG_LONG. If it sees any
+other value, it fails the testcase.
+
+This way, we are *sure* there is no in between state because we
+effectively acted like an OS and switched to another thread after
+every single instruction of the routine is executed and looked at the
+results each time.
+
+We use the same idea to test for data races to see if an illegal load
+has been hoisted, or that two parallel bitfield writes don't overlap
+in a data race.
+
+Below is a skeleton of how a test should look like. For more details,
+look at the tests themselves.
+
+ANATOMY OF A TEST
+-----------------
+
+/* { dg-do link } */
+/* { dg-options "-some-flags" } */
+/* { dg-final { simulate-thread } } */
+
+/* NOTE: Any failure must be indicated by displaying "FAIL:". */
+
+#include "simulate-thread.h"
+
+/* Called before each instruction, simulating another thread executing. */
+void simulate_thread_other_threads()
+{
+}
+
+/* Called after each instruction. Returns 1 if any inconsistency is
+ found, 0 otherwise. */
+int simulate_thread_step_verify()
+{
+ if (some_problem)
+ {
+ printf("FAIL: reason\n");
+ return 1;
+ }
+ return 0;
+}
+
+/* Called at the end of the program (simulate_thread_fini == 1). Verifies
+ the state of the program and returns 1 if any inconsistency is
+ found, 0 otherwise. */
+int simulate_thread_final_verify()
+{
+ if (some_problem)
+ {
+ printf("FAIL: reason\n");
+ return 1;
+ }
+ return 0;
+}
+
+/* The gdb script will break on simulate_thread_main(), so make sure
+ GCC does not inline it, thus making the break point fail. */
+__attribute__((noinline))
+void simulate_thread_main()
+{
+ /* Do stuff. */
+}
+
+int main()
+{
+
+ /* Perform any setup code that will run outside of the testing
+ harness. Put code here that you do NOT want to be interrupted on
+ an instruction basis. E.g., setup code, and system library
+ calls. */
+
+ /* Do un-instrumented stuff. */
+ /* ... */
+
+ /* Start the instrumented show. */
+ simulate_thread_main();
+
+ /* Must be called at the end of the test. */
+ simulate_thread_done();
+
+ return 0;
+}
--- /dev/null
+# Copyright (C) 2011 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 GCC; see the file COPYING3. If not see
+# <http://www.gnu.org/licenses/>.
+
+# Your run of the mill dg test, but verify that we have a working GDB first.
+
+load_lib gcc-dg.exp
+load_lib gcc-simulate-thread.exp
+load_lib torture-options.exp
+
+dg-init
+torture-init
+set-torture-options [list \
+ { -O0 -g } \
+ { -O1 -g } \
+ { -O2 -g } \
+ { -O3 -g } \
+ { -Os -g } ]
+
+if [gdb-exists] {
+ gcc-dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/*.c]] ""
+ gcc-dg-runtest [lsort [glob $srcdir/c-c++-common/simulate-thread/*.c]] ""
+}
+
+torture-finish
+dg-finish
--- /dev/null
+set height 0
+break simulate_thread_main
+disp/i $pc
+run
+
+set $ret = 0
+while (simulate_thread_fini != 1) && (! $ret)
+ call simulate_thread_other_threads()
+ stepi
+ set $ret |= simulate_thread_step_verify()
+end
+
+if (! $ret)
+ set $ret |= simulate_thread_final_verify()
+end
+continue
+quit $ret
--- /dev/null
+int simulate_thread_fini = 0;
+
+void __attribute__((noinline))
+simulate_thread_done ()
+{
+ simulate_thread_fini = 1;
+}
process-message saved-dg-warning "" $args
}
+# Check the existence of a gdb in the path, and return true if there
+# is one.
+#
+# Set env(GDB_FOR_GCC_TESTING) accordingly.
+
+proc gdb-exists { args } {
+ if ![info exists ::env(GDB_FOR_GCC_TESTING)] {
+ global GDB
+ if ![info exists ::env(GDB_FOR_GCC_TESTING)] {
+ if [info exists GDB] {
+ setenv GDB_FOR_GCC_TESTING "$GDB"
+ } else {
+ setenv GDB_FOR_GCC_TESTING "[transform gdb]"
+ }
+ }
+ }
+ if { [which $::env(GDB_FOR_GCC_TESTING)] != 0 } {
+ return 1;
+ }
+ return 0;
+}
+
set additional_prunes ""
--- /dev/null
+# Copyright (C) 2011 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 GCC; see the file COPYING3. If not see
+# <http://www.gnu.org/licenses/>.
+
+# Utility for running a given test through the simulate-thread harness
+# using gdb. This is invoked via dg-final.
+#
+# Adapted from the guality harness.
+#
+# Call 'fail' if a given test printed "FAIL:", otherwise call 'pass'.
+
+proc simulate-thread { args } {
+ if { ![isnative] || [is_remote target] } { return }
+
+ if { [llength $args] == 1 } {
+ switch [dg-process-target [lindex $args 0]] {
+ "F" { setup_xfail "*-*-*" }
+ }
+ }
+
+ # This assumes that we are three frames down from dg-test, and that
+ # it still stores the filename of the testcase in a local variable "name".
+ # A cleaner solution would require a new DejaGnu release.
+ upvar 2 name testcase
+ upvar 2 prog prog
+ upvar 2 srcdir testsuite_dir
+
+ set gdb_name $::env(GDB_FOR_GCC_TESTING)
+ set exec_file "[file rootname [file tail $prog]].exe"
+ set cmd_file "$testsuite_dir/gcc.dg/simulate-thread/simulate-thread.gdb"
+
+ if ![file exists $exec_file] {
+ return
+ }
+
+ send_log "Spawning: $gdb_name -nx -nw -quiet -x $cmd_file ./$exec_file\n"
+ set res [remote_spawn target "$gdb_name -nx -nw -x $cmd_file ./$exec_file"]
+ if { $res < 0 || $res == "" } {
+ unsupported "$testcase"
+ return
+ }
+
+ set gdb_worked 0
+ remote_expect target [timeout_value] {
+ # Too old GDB
+ -re "Unhandled dwarf expression|Error in sourced command file" {
+ unsupported "$testcase"
+ remote_close target
+ return
+ }
+ -re "FAIL:" {
+ fail "$testcase"
+ remote_close target
+ return
+ }
+ # If the gdb output contained simulate_thread_main, assume
+ # that at the very least, we had a working gdb that was able
+ # to break in simulate_thread_main.
+ -re "simulate_thread_main" {
+ set gdb_worked 1
+ exp_continue
+ }
+ timeout {
+ unsupported "$testcase"
+ remote_close target
+ return
+ }
+ }
+
+ remote_close target
+ if {$gdb_worked} {
+ pass "$testcase"
+ } else {
+ # Fail in the absence of a sane GDB.
+ fail "$testcase"
+ }
+ return
+}
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