GDB hangs when attaching to process on mips-irix

[Joel Brobecker <brobecker at adacore dot com>]

Trying to attach GDB to a running process does not work. It shows
that it attached to the process, then read its shared library symbols,
but then hung:

    (gdb) att 5866121
    Attaching to program `/p...]/foo', process 5866121
    [New process 5866121]
    Retry #1:
    Retry #2:
    Retry #3:
    Retry #4:
    Reading symbols from /[...]/libgnat-6.4.so...done. 
    Loaded symbols for /[...]/libgnat-6.4.so
    Reading symbols from /usr/lib32/libexc.so...done.
    Loaded symbols for /usr/lib32/libexc.so
    Reading symbols from /[...]/libgcc_s.so.1...done.
    Loaded symbols for /[...]/libgcc_s.so.1
    Reading symbols from /usr/lib32/libm.so...done.
    ***HANGS***

The problem is fairly simple: The solib-irix create_inferior_hook
tries to wait until the process reaches the solib breapoint signalling
when the shared libraries have been mapped in memory.  However, this
is only needed when spawing a process - in the context of attaching
to a process, the SOs have already been mapped in memory, and thus
GDB hangs, waiting for a breakpoint that will never happen.
          
The fix is fairly classic: Do nothing in this create_inferior_hook
when attaching...

gdb/ChangeLog:

        GDB hangs when attaching to process on mips-irix.
        * solib-irix.c (irix_solib_create_inferior_hook): Do nothing if
        attaching to a process.

-- 
Joel

gdb/ChangeLog:

        GDB hangs when attaching to process on mips-irix.
        * solib-irix.c (irix_solib_create_inferior_hook): Do nothing if
        attaching to a process.
---
 gdb/solib-irix.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/gdb/solib-irix.c b/gdb/solib-irix.c
index 596f9a0..4c97263 100644
--- a/gdb/solib-irix.c
+++ b/gdb/solib-irix.c
@@ -442,6 +442,13 @@ irix_solib_create_inferior_hook (void)
   struct inferior *inf;
   struct thread_info *tp;
 
+  inf = current_inferior ();
+
+  /* If we are attaching to the inferior, the shared libraries
+     have already been mapped, so nothing more to do.  */
+  if (inf->attach_flag)
+    return;
+
   if (!enable_break ())
     {
       warning (_("shared library handler failed to enable breakpoint"));
@@ -453,7 +460,6 @@ irix_solib_create_inferior_hook (void)
      can go groveling around in the dynamic linker structures to find
      out what we need to know about them. */
 
-  inf = current_inferior ();
   tp = inferior_thread ();
 
   clear_proceed_status ();
-- 
1.5.4.3