[RFA] [PATCH] gdb.base/break.exp

[Michael Elizabeth Chastain <chastain at cygnus dot com>]

On Red Hat Linux 6.2 native, I see these test failures:

  FAIL: gdb.base/break.exp: break main #1
  FAIL: gdb.base/break.exp: break main #2
  FAIL: gdb.base/break.exp: clear main

I have an analysis and a patch.

First, the analysis.  This test case sets multiple breakpoints on a single
location and then clears all of them at once.  The location for the test
is the well-known function 'main'.

Unfortunately, at that point of the test execution, the program counter
is in a library function __libc_start_main which has a parameter named
'main'.  This parameter name shadows the global function name 'main',
so that gdb-under-test resolves the name 'main' to this parameter, not
to the global function 'main'.  This is normal C scoping.  And of course,
it is illegal to set a breakpoint on a parameter.

Here is an excerpt from gdb.log.  Note where the 'finish' command
leaves the target program; and note the names of the parameters to
__libc_start_main.

  finish
  Run till exit from #0  main (argc=1, argv=0xbffff5d4, envp=0xbffff5dc) at ../../../../src/gdb/testsuite/gdb.base/break.c:75
  720
  0x4004d9cb in __libc_start_main (main=0x80484a8 <main>, argc=1, argv=0xbffff5d4, init=0x8048318 <_init>, fini=0x80485ac <_fini>, rtld_fini=0x4000ae60 <_dl_fini>, stack_end=0xbffff5cc) at ../sysdeps/generic/libc-start.c:92
  92	../sysdeps/generic/libc-start.c: No such file or directory.
  Value returned is $2 = 0
  (gdb) PASS: gdb.base/break.exp: finish from outermost frame disallowed
  break main
  "main" is not a function
  (gdb) FAIL: gdb.base/break.exp: break main #1
  break main
  "main" is not a function
  (gdb) FAIL: gdb.base/break.exp: break main #2
  clear main
  "main" is not a function
  (gdb) FAIL: gdb.base/break.exp: clear main
  ---

My fix is trivial: use a different function name for the
set-multiple-breakpoints-and-clear-them-all test.

Michael Chastain
chastain@redhat.com
"love without fear"

---

2000-11-23  Michael Chastain  <chastain@redhat.com>

	* break.exp (test_clear_command): use a different function
	than 'main' for the test function.  On glibc based systems,
	__libc_start_main is the current function at this point in
	execution, and __libc_start_main has a parameter named 'main'.

Index: gdb/testsuite/gdb.base/break.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.base/break.exp,v
retrieving revision 1.6
diff -c -3 -p -r1.6 break.exp
*** gdb/testsuite/gdb.base/break.exp	2000/11/17 16:24:48	1.6
--- gdb/testsuite/gdb.base/break.exp	2000/11/23 18:45:14
*************** if [istarget "hppa*-*-hpux*"] then {
*** 707,718 ****
  
  
  proc test_clear_command {} {
!     gdb_test "break main" "Breakpoint.*at.*" "break main #1"
!     gdb_test "break main" "Breakpoint.*at.*" "break main #2"
  
      # We don't test that it deletes the correct breakpoints.  We do at
      # least test that it deletes more than one breakpoint.
!     gdb_test "clear main" {Deleted breakpoints [0-9]+ [0-9]+.*}
  }
  
  #
--- 707,718 ----
  
  
  proc test_clear_command {} {
!     gdb_test "break factorial" "Breakpoint.*at.*" "break factorial #1"
!     gdb_test "break factorial" "Breakpoint.*at.*" "break factorial #2"
  
      # We don't test that it deletes the correct breakpoints.  We do at
      # least test that it deletes more than one breakpoint.
!     gdb_test "clear factorial" {Deleted breakpoints [0-9]+ [0-9]+.*}
  }
  
  #