[RFA]corelow.c: Add tid to add_to_thread_list

[Hui Zhu <teawater@gmail.com>]

Hi,

I found that from gdb 7.1 to gdb-cvs-head cannot analyze the core file
that get from kdump.
What I got:
[New <main task>]
[New Thread 2719]
../../src/gdb/thread.c:884: internal-error: switch_to_thread:
Assertion `inf != NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
That is because:
 objdump -h ./vmcore

./vmcore:     file format elf64-x86-64

Sections:
Idx Name          Size      VMA               LMA               File off  Algn
  0 note0         00000a48  0000000000000000  0000000000000000  00000238  2**0
                  CONTENTS, READONLY
  1 .reg/0        000000d8  0000000000000000  0000000000000000  000002bc  2**2
                  CONTENTS
  2 .reg          000000d8  0000000000000000  0000000000000000  000002bc  2**2
                  CONTENTS
  3 .reg/2719     000000d8  0000000000000000  0000000000000000  00000420  2**2
                  CONTENTS
  4 .reg/0        000000d8  0000000000000000  0000000000000000  00000584  2**2
                  CONTENTS
  5 .reg/0        000000d8  0000000000000000  0000000000000000  000006e8  2**2
                  CONTENTS
Each of reg/n is a cpu core note.  It will be a GDB thread.  n is the
prstatus.pr_pid that will be the thread lwpid.  Because the 3 threads
pid is same, so GDB get error.

I make a patch for kernel (http://lkml.org/lkml/2010/8/3/75) but they
think it should be fixed in user space.
So I add the tid to add_to_thread_list.

Please help me review it.

Thanks,
Hui

2010-08-03  Hui Zhu  <teawater@gmail.com>

	* corelow.c(add_to_thread_list): Add tid.


---
 corelow.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/corelow.c
+++ b/corelow.c
@@ -244,7 +244,7 @@ add_to_thread_list (bfd *abfd, asection
 {
   ptid_t ptid;
   int core_tid;
-  int pid, lwpid;
+  int pid, lwpid, tid;
   asection *reg_sect = (asection *) reg_sect_arg;

   if (strncmp (bfd_section_name (abfd, asect), ".reg/", 5) != 0)
@@ -278,7 +278,14 @@ add_to_thread_list (bfd *abfd, asection
   if (current_inferior ()->pid == 0)
     inferior_appeared (current_inferior (), pid);

-  ptid = ptid_build (pid, lwpid, 0);
+  tid = 0;
+get_ptid:
+  ptid = ptid_build (pid, lwpid, tid);
+  if (find_thread_ptid (ptid))
+    {
+      tid ++;
+      goto get_ptid;
+    }

   add_thread (ptid);