testsuite: Regression for foll-vfork.exp

fe33faff35a8ee19db823149e764e3373e603bb9 is the first bad commit
commit fe33faff35a8ee19db823149e764e3373e603bb9
Author: Simon Marchi <simon.marchi@ericsson.com>
Date:   Tue Dec 22 10:52:31 2015 -0500
    Remove HP-UX reference in foll-vfork.exp

FAIL: gdb.base/foll-vfork.exp: exec: vfork parent follow, finish after tcatch vfork: continue to vfork
FAIL: gdb.base/foll-vfork.exp: exec: vfork child follow, finish after tcatch vfork: continue to vfork
FAIL: gdb.base/foll-vfork.exp: exit: vfork parent follow, finish after tcatch vfork: continue to vfork
FAIL: gdb.base/foll-vfork.exp: exit: vfork child follow, finish after tcatch vfork: continue to vfork

It happens for plain gdb.base/foll-vfork.exp runtest on Fedora 23 x86_64.

-Temporary catchpoint 2 (vforked process 24562), vfork () at ../sysdeps/unix/sysv/linux/x86_64/vfork.S:52^M
+Temporary catchpoint 2 (vforked process 25345), vfork () at ../sysdeps/unix/sysv/linux/x86_64/vfork.S:52^M
 52             pushq   %rdi^M
 Current language:  auto^M
 The current source language is "auto; currently asm".^M
-(gdb) PASS: gdb.base/foll-vfork.exp: exec: vfork parent follow, finish after tcatch vfork: continue to vfork
+(gdb) FAIL: gdb.base/foll-vfork.exp: exec: vfork parent follow, finish after tcatch vfork: continue to vfork

-Temporary catchpoint 2 (vforked process 24629), vfork () at ../sysdeps/unix/sysv/linux/x86_64/vfork.S:52^M
+Temporary catchpoint 2 (vforked process 25411), vfork () at ../sysdeps/unix/sysv/linux/x86_64/vfork.S:52^M
 52             pushq   %rdi^M
 Current language:  auto^M
 The current source language is "auto; currently asm".^M
-(gdb) PASS: gdb.base/foll-vfork.exp: exec: vfork child follow, finish after tcatch vfork: continue to vfork
+(gdb) FAIL: gdb.base/foll-vfork.exp: exec: vfork child follow, finish after tcatch vfork: continue to vfork

So I have reverted it and just simplified the comment.

The third case is not necessary during testing but I have changed back all the
3 cases.

Pedro Alves:
I know it was that way before, but would you mind moving this to a helper
proc.

gdb/testsuite/ChangeLog
2016-01-11  Jan Kratochvil  <jan.kratochvil@redhat.com>
	    Pedro Alves  <palves@redhat.com>

	* gdb.base/foll-vfork.exp (tcatch_vfork_then_parent_follow)
	(tcatch_vfork_then_child_follow_exec)
	(tcatch_vfork_then_child_follow_exit): Revert back DWARF vfork
	identification.

2 files changed, 29 insertions, 6 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index a0eba33..8b0425b 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,4 +1,12 @@
 2016-01-11  Jan Kratochvil  <jan.kratochvil@redhat.com>
+	    Pedro Alves  <palves@redhat.com>
+
+	* gdb.base/foll-vfork.exp (tcatch_vfork_then_parent_follow)
+	(tcatch_vfork_then_child_follow_exec)
+	(tcatch_vfork_then_child_follow_exit): Revert back DWARF vfork
+	identification.
+
+2016-01-11  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	* gdb.guile/scm-value.exp (test_value_in_inferior): Set print elements
 	and repeats to unlimited.
diff --git a/gdb/testsuite/gdb.base/foll-vfork.exp b/gdb/testsuite/gdb.base/foll-vfork.exp
index ed25487..173a7c3 100644
--- a/gdb/testsuite/gdb.base/foll-vfork.exp
+++ b/gdb/testsuite/gdb.base/foll-vfork.exp
@@ -212,6 +212,21 @@ proc vfork_and_exec_child_follow_through_step {} {
    exec sleep 1
 }}
 
+proc continue_to_vfork {} {
+   global gdb_prompt
+
+   # A vfork catchpoint may stop in either "vfork" or "_vfork".
+   set test "continue to vfork"
+   gdb_test_multiple "continue" $test {
+      -re "vfork \\(\\) at .*$gdb_prompt $" {
+	  pass $test
+      }
+      -re "0x\[0-9a-fA-F\]*.*(vfork|__kernel_v?syscall).*$gdb_prompt " {
+	  pass $test
+      }
+   }
+}
+
 proc tcatch_vfork_then_parent_follow {} {
   with_test_prefix "vfork parent follow, finish after tcatch vfork" {
    global gdb_prompt
@@ -222,8 +237,8 @@ proc tcatch_vfork_then_parent_follow {} {
    gdb_test_no_output "set follow-fork parent"
 
    gdb_test "tcatch vfork" "Catchpoint .*(vfork).*"
-   gdb_test "continue" "0x\[0-9a-fA-F\]*.*(vfork|__kernel_v?syscall).*" \
-	"continue to vfork"
+
+   continue_to_vfork
 
    set linenum [gdb_get_line_number "pid = vfork ();"]
    set test "finish"
@@ -254,8 +269,8 @@ proc tcatch_vfork_then_child_follow_exec {} {
    gdb_test_no_output "set follow-fork child"
 
    gdb_test "tcatch vfork" "Catchpoint .*(vfork).*"
-   gdb_test "continue" "0x\[0-9a-fA-F\]*.*(vfork|__kernel_v?syscall).*" \
-	"continue to vfork"
+
+   continue_to_vfork
 
    set linenum1 [gdb_get_line_number "pid = vfork ();"]
    set linenum2 [gdb_get_line_number "printf(\"Hello from vforked-prog" ${srcfile2}]
@@ -290,8 +305,8 @@ proc tcatch_vfork_then_child_follow_exit {} {
    gdb_test_no_output "set follow-fork child"
 
    gdb_test "tcatch vfork" "Catchpoint .*(vfork).*"
-   gdb_test "continue" "0x\[0-9a-fA-F\]*.*(vfork|__kernel_v?syscall).*" \
-	"continue to vfork"
+
+   continue_to_vfork
 
    set test "finish"
    gdb_test_multiple "finish" $test {