Re: [patch/RFA] multiarch INSTRUCTION_NULLIFIED

[Randolph Chung <randolph at tausq dot org>]

> 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
http://www.tausq.org/