Re: [patch/RFA] multiarch INSTRUCTION_NULLIFIED

Randolph Chung
2004-12-02T05:24:30Z

> PPS: A gdb.arch/ addition to tickle the basic edge case would be a
> helpful way of capturing this knowledge.

how about this... my first gdb testcase, so hopefully i didn't do
anything too wrong :)

74 PASSes, 3 FAILs with the old code (assuming the instruction_nullified
logic is removed). 77 PASSes with my previous patch.

randolph

2004-12-01 Randolph Chung <tausq@debian.org>

* gdb.arch/pa-nullify.exp: New file.
* gdb.arch/pa-nullify.c: New file.

--- /dev/null 2004-08-25 14:59:25.000000000 -0700
+++ pa-nullify.exp 2004-12-01 21:21:13.451861856 -0800
@@ -0,0 +1,217 @@
+# Copyright 2004 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 2 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, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+#
+# This file is part of the gdb testsuite.
+
+# NOTE: this test is specific to how gcc generates code. In particular, we
+# are testing for the case where the last insn of a function is a "bv,n r0(%rp)"
+# and the insn in the delay slot of that branch belongs to the next function.
+
+if $tracelevel {
+ strace $tracelevel
+}
+
+set prms_id 0
+set bug_id 0
+
+# Test handling of nullified instructions for the pa target.
+
+if ![istarget "hppa*-*-*"] then {
+ verbose "Skipping hppa nullification tests."
+ return
+}
+
+set testfile "pa-nullify"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+set gcorefile ${objdir}/${subdir}/${testfile}.gcore
+
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+ unsupported "Testcase compile failed."
+ return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# In the first test, we do a "step" on a function whose last instruction
+# contains a branch-with-nullify. The instruction in the delay slot belongs
+# to the next function. We verify that when we step off the first function
+# that we end up back at the caller and not at the second instruction.
+
+gdb_breakpoint foo
+gdb_test "run" ".*Breakpoint 1, foo \\(x=1\\).*" "Breakpoint at foo"
+gdb_test "step" ".*main \\(.*\\) at .*pa-nullify.c:30.*" "step back to main"
+
+# In the second test, we do a single step through each instruction of a function
+# and verify that we get a proper backtrace, even when we are in a nullified
+# instruction that belongs to the next function. We also verify that when
+# stepping over a branch-with-nullify insn that we stay on the same insn for
+# two steps.
+
+if { ! [ runto main ] } then { gdb_suppress_tests; }
+
+send_gdb "print foo\n"
+gdb_expect {
+ -re ".* = {int \\(int\\)} ($hex) <foo>.*$gdb_prompt $" {
+ set baddr $expect_out(1,string)
+ verbose "Breakpoint address at $baddr"
+ pass "print foo = $baddr"
+ }
+ default {
+ fail "print foo"
+ gdb_suppress_tests
+ } timeout {
+ fail "cannot get address of foo (timed out)."
+ gdb_suppress_tests
+ }
+}
+
+gdb_breakpoint "*$baddr"
+
+gdb_test "display /i \$pc" "1: x/i +\\\$pc.*" "display /i \$pc"
+gdb_test "continue" ".*Breakpoint \[0-9\], foo \\(x=1\\) at .*pa-nullify.c:23.*" "break at first insn of foo"
+
+set done 0
+set iter 0
+while { $done == 0 && $iter < 20 } {
+ send_gdb "backtrace\n"
+ gdb_expect {
+ -re ".*foo \\(x=.*\\).* main \\(.*\\).*$gdb_prompt $" {
+ pass "backtrace from foo"
+ }
+ -re "$gdb_prompt $" {
+ fail "backtrace from foo"
+ gdb_suppress_tests
+ }
+ timeout {
+ fail "(timeout) backtrace from foo"
+ gdb_suppress_tests
+ }
+ }
+
+ send_gdb "stepi\n"
+ gdb_expect {
+ -re ".*: x/i +\\\$pc.*:\[ \t\]+(.*)\r.*$gdb_prompt $" {
+ set insn $expect_out(1,string)
+ pass "x/i \$pc = $insn"
+ } timeout {
+ fail "(timeout) x/i \$pc"
+ gdb_suppress_tests
+ break
+ }
+ }
+
+ incr iter
+
+ if { $insn == "bv,n r0(rp)" } {
+ pass "found bv,n insn"
+ set done 1
+ }
+}
+
+send_gdb "stepi\n"
+gdb_expect {
+ -re ".*bv,n r0\\(rp\\)\r.*$gdb_prompt $" {
+ pass "restep on nullified instruction"
+ }
+ -re ".*bar.*\r.*x/i.*bar.*\r.*$gdb_prompt $" {
+ fail "step on nullification instruction ended in next function"
+ }
+ timeout {
+ fail "(timeout) restep on nullified instruction"
+ }
+}
+incr iter
+
+# Lastly, we do a single step through each instruction and generate a core file.
+# Then, load the core file and verify that we can get a proper backtrace.
+
+if ![isnative] then {
+ verbose "skipping core file tests on non-native configuration"
+ return
+}
+
+send_gdb "undisplay 1\n"
+
+proc do_core_test { count } {
+ global gcorefile
+ global gdb_prompt
+ global hex
+
+ if { ! [ runto_main ] } then { gdb_suppress_tests; }
+
+ set baddr "0"
+ send_gdb "print foo\n"
+ gdb_expect {
+ -re ".* = {int \\(int\\)} ($hex) <foo>.*$gdb_prompt $" {
+ set baddr $expect_out(1,string)
+ verbose "Breakpoint address at $baddr"
+ pass "print foo = $baddr #$count"
+ }
+ default {
+ fail "print foo #$count"
+ gdb_suppress_tests
+ }
+ timeout {
+ fail "cannot get address of foo (timed out). #$count"
+ gdb_suppress_tests
+ }
+ }
+ gdb_breakpoint "*$baddr"
+
+ gdb_test "continue" ".*Breakpoint \[0-9\]*, foo \\(x=1\\) at .*pa-nullify.c:23.*" "break at first insn of foo #$count"
+
+ gdb_test "si $count"
+
+ set gcore_works 0
+ set escapedfilename [string_to_regexp $gcorefile]
+ gdb_test_multiple "gcore $gcorefile" "gcore" {
+ -re "Saved corefile ${escapedfilename}\[\r\n\]+$gdb_prompt $" {
+ pass "gcore #$count"
+ set gcore_works 1
+ }
+ -re "Can't create a corefile\[\r\n\]+$gdb_prompt $" {
+ unsupported "gcore"
+ }
+ }
+
+ if { $gcore_works } {
+ gdb_test "core $gcorefile" "Core was generated by.*" \
+ "load core file #$count" "A program is being debugged already.*" "y"
+
+ send_gdb "backtrace\n"
+ gdb_expect {
+ -re ".*foo \\(x=.*\\).* main \\(.*\\).*$gdb_prompt $" {
+ pass "backtrace from foo #$count"
+ }
+ -re "$gdb_prompt $" {
+ fail "backtrace from foo #$count"
+ gdb_suppress_tests
+ }
+ timeout {
+ fail "(timeout) backtrace from foo in gcore #$count"
+ gdb_suppress_tests
+ }
+ }
+ }
+}
+
+for { set i 1 } { $i <= $iter } {incr i} {
+ do_core_test $i
+}
--- /dev/null 2004-08-25 14:59:25.000000000 -0700
+++ pa-nullify.c 2004-12-01 21:19:51.324347136 -0800
@@ -0,0 +1,30 @@
+/* PA nullification test program.
+
+ Copyright 2004 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 2 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, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+int foo(int x)
+{ return x; }
+
+void bar(void) { }
+
+int main(int argc, char **argv)
+{
+ return foo(argc);
+}

--
Randolph Chung
Debian GNU/Linux Developer, hppa/ia64 ports