* dbxread.c, partial-stab.h (near N_SO): SO stabs with blank

	names mean end of .o file.
	* infrun.c (wait_for_inferior):  Clean up multi-thread logic near
	top of routine.  Handle new thread notification cleanly.
	* lynx-nat.c (child_wait):  General cleanups, handle new LynxOS
	thread notification scheme.
	* (child_resume):  General cleanups, handle resumption of all
	threads properly.

4 files changed, 186 insertions, 149 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4d84f37..2a65fb5 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,14 @@
+Tue Jun 28 15:28:01 1994  Stu Grossman  (grossman@cygnus.com)
+
+	* dbxread.c, partial-stab.h (near N_SO):  SO stabs with blank
+	names mean end of .o file.
+	* infrun.c (wait_for_inferior):  Clean up multi-thread logic near
+	top of routine.  Handle new thread notification cleanly.
+	* lynx-nat.c (child_wait):  General cleanups, handle new LynxOS
+	thread notification scheme.
+	* (child_resume):  General cleanups, handle resumption of all
+	threads properly.
+
 Mon Jun 27 09:57:23 1994  Steve Chamberlain  (sac@cirdan.cygnus.com)
 
 	* ser-go32.c: Rewrite to run under windows.
diff --git a/gdb/dbxread.c b/gdb/dbxread.c
index a77f646..5445c8a 100644
--- a/gdb/dbxread.c
+++ b/gdb/dbxread.c
@@ -1903,11 +1903,16 @@ process_one_symbol (type, desc, valu, name, section_offsets, objfile)
 	  end_symtab (valu, 0, 0, objfile, SECT_OFF_TEXT);
 	  end_stabs ();
 	}
+
+      /* Null name means this just marks the end of text for this .o file.
+	 Don't start a new symtab in this case.  */
+      if (*name == '\000')
+	break;
+
       start_stabs ();
       start_symtab (name, NULL, valu);
       break;
 
-
     case N_SOL:
       /* This type of symbol indicates the start of data for
 	 a sub-source-file, one whose contents were copied or
@@ -2358,12 +2363,13 @@ elfstab_build_psymtabs (objfile, section_offsets, mainline,
 
 void
 stabsect_build_psymtabs (objfile, section_offsets, mainline, stab_name,
-			 stabstr_name)
+			 stabstr_name, text_name)
      struct objfile *objfile;
      struct section_offsets *section_offsets;
      int mainline;
      char *stab_name;
      char *stabstr_name;
+     char *text_name;
 {
   int val;
   bfd *sym_bfd = objfile->obfd;
@@ -2384,9 +2390,9 @@ stabsect_build_psymtabs (objfile, section_offsets, mainline, stab_name,
   objfile->sym_stab_info = (PTR) xmalloc (sizeof (struct dbx_symfile_info));
   memset (DBX_SYMFILE_INFO (objfile), 0, sizeof (struct dbx_symfile_info));
 
-  DBX_TEXT_SECT (objfile) = bfd_get_section_by_name (sym_bfd, ".text");
+  DBX_TEXT_SECT (objfile) = bfd_get_section_by_name (sym_bfd, text_name);
   if (!DBX_TEXT_SECT (objfile))
-    error ("Can't find .text section in symbol file");
+    error ("Can't find %s section in symbol file", text_name);
 
   DBX_SYMBOL_SIZE    (objfile) = sizeof (struct external_nlist);
   DBX_SYMCOUNT       (objfile) = bfd_section_size (sym_bfd, stabsect)
@@ -2422,36 +2428,6 @@ stabsect_build_psymtabs (objfile, section_offsets, mainline, stab_name,
   dbx_symfile_read (objfile, section_offsets, 0);
 }
 
-/* Scan and build partial symbols for a SOM symbol file.
-   This SOM file has already been processed to get its minimal symbols.
-
-   OBJFILE is the object file we are reading symbols from.
-   ADDR is the address relative to which the symbols are (e.g.
-   the base address of the text segment).
-   MAINLINE is true if we are reading the main symbol
-   table (as opposed to a shared lib or dynamically loaded file).
-
-   */
-
-void
-somstab_build_psymtabs (objfile, section_offsets, mainline)
-     struct objfile *objfile;
-     struct section_offsets *section_offsets;
-     int mainline;
-{
-  free_header_files ();
-  init_header_files ();
-
-  /* This is needed to debug objects assembled with gas2.  */
-  processing_acc_compilation = 1;
-
-  /* In a SOM file, we've already installed the minimal symbols that came
-     from the SOM (non-stab) symbol table, so always act like an
-     incremental load here. */
-
-  dbx_symfile_read (objfile, section_offsets, mainline);
-}
-
 /* Parse the user's idea of an offset for dynamic linking, into our idea
    of how to represent it for fast symbol reading.  */
 
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 08e3bfd..9a9e35c 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -294,6 +294,24 @@ proceed (addr, siggnal, step)
   else
     write_pc (addr);
 
+#ifdef PREPARE_TO_PROCEED
+  /* In a multi-threaded task we may select another thread and then continue.
+     
+     In this case the thread that stopped at a breakpoint will immediately
+     cause another stop, if it is not stepped over first. On the other hand,
+     if (ADDR != -1) we only want to single step over the breakpoint if we did
+     switch to another thread.
+
+     If we are single stepping, don't do any of the above.
+     (Note that in the current implementation single stepping another
+     thread after a breakpoint and then continuing will cause the original
+     breakpoint to be hit again, but you can always continue, so it's not
+     a big deal.)  */
+
+  if (! step && PREPARE_TO_PROCEED && breakpoint_here_p (read_pc ()))
+    oneproc = 1;
+#endif /* PREPARE_TO_PROCEED */
+
   if (trap_expected_after_continue)
     {
       /* If (step == 0), a trap will be automatically generated after
@@ -437,11 +455,25 @@ wait_for_inferior ()
 
   while (1)
     {
+      /* We have to invalidate the registers BEFORE calling target_wait because
+	 they can be loaded from the target while in target_wait.  This makes
+	 remote debugging a bit more efficient for those targets that provide
+	 critical registers as part of their normal status mechanism. */
+
+      registers_changed ();
+
       pid = target_wait (-1, &w);
 
-      /* Clean up saved state that will become invalid.  */
       flush_cached_frames ();
-      registers_changed ();
+
+      /* If it's a new process, add it to the thread database */
+
+      if (pid != inferior_pid
+	  && !in_thread_list (pid))
+	{
+	  fprintf_unfiltered (gdb_stderr, "[New %s]\n", target_pid_to_str (pid));
+	  add_thread (pid);
+	}
 
       switch (w.kind)
 	{
@@ -507,125 +539,104 @@ wait_for_inferior ()
 
       stop_signal = w.value.sig;
 
-      if (pid != inferior_pid)
-	{
-	  int save_pid = inferior_pid;
+      stop_pc = read_pc_pid (pid);
 
-	  inferior_pid = pid;	/* Setup for target memory/regs */
-	  registers_changed ();
-	  stop_pc = read_pc ();
-	  inferior_pid = save_pid;
-	  registers_changed ();
-	}
-      else
-	stop_pc = read_pc ();
+      /* See if a thread hit a thread-specific breakpoint that was meant for
+	 another thread.  If so, then step that thread past the breakpoint,
+	 and continue it.  */
 
       if (stop_signal == TARGET_SIGNAL_TRAP
+	  && breakpoints_inserted
 	  && breakpoint_here_p (stop_pc - DECR_PC_AFTER_BREAK))
 	{
+	  random_signal = 0;
 	  if (!breakpoint_thread_match (stop_pc - DECR_PC_AFTER_BREAK, pid))
 	    {
 	      /* Saw a breakpoint, but it was hit by the wrong thread.  Just continue. */
-	      if (breakpoints_inserted)
-		{
-		  if (pid != inferior_pid)
-		    {
-		      int save_pid = inferior_pid;
-
-		      inferior_pid = pid;
-		      registers_changed ();
-		      write_pc (stop_pc - DECR_PC_AFTER_BREAK);
-		      inferior_pid = save_pid;
-		      registers_changed ();
-		    }
-		  else
-		    write_pc (stop_pc - DECR_PC_AFTER_BREAK);
-
-		  remove_breakpoints ();
-		  target_resume (pid, 1, TARGET_SIGNAL_0); /* Single step */
-		  /* FIXME: What if a signal arrives instead of the single-step
-		     happening?  */
-		  target_wait (pid, &w);
-		  insert_breakpoints ();
-		}
-	      target_resume (-1, 0, TARGET_SIGNAL_0);
+	      write_pc (stop_pc - DECR_PC_AFTER_BREAK);
+
+	      remove_breakpoints ();
+	      target_resume (pid, 1, TARGET_SIGNAL_0); /* Single step */
+	      /* FIXME: What if a signal arrives instead of the single-step
+		 happening?  */
+	      target_wait (pid, &w);
+	      insert_breakpoints ();
+	      target_resume (pid, 0, TARGET_SIGNAL_0);
 	      continue;
 	    }
-	  else
-	    if (pid != inferior_pid)
-	      goto switch_thread;
 	}
+      else
+	random_signal = 1;
+
+      /* See if something interesting happened to the non-current thread.  If
+         so, then switch to that thread, and eventually give control back to
+	 the user.  */
 
       if (pid != inferior_pid)
 	{
 	  int printed = 0;
 
-	  if (!in_thread_list (pid))
+	  /* If it's a random signal for a non-current thread, notify user
+	     if he's expressed an interest.  */
+
+	  if (random_signal
+	      && signal_print[stop_signal])
 	    {
-	      fprintf_unfiltered (gdb_stderr, "[New %s]\n", target_pid_to_str (pid));
-	      add_thread (pid);
+	      printed = 1;
+	      target_terminal_ours_for_output ();
+	      printf_filtered ("\nProgram received signal %s, %s.\n",
+			       target_signal_to_name (stop_signal),
+			       target_signal_to_string (stop_signal));
+	      gdb_flush (gdb_stdout);
+	    }
+
+	  /* If it's not SIGTRAP and not a signal we want to stop for, then
+	     continue the thread. */
+
+	  if (stop_signal != TARGET_SIGNAL_TRAP
+	      && !signal_stop[stop_signal])
+	    {
+	      if (printed)
+		target_terminal_inferior ();
 
-	      target_resume (-1, 0, TARGET_SIGNAL_0);
+	      /* Clear the signal if it should not be passed.  */
+	      if (signal_program[stop_signal] == 0)
+		stop_signal = TARGET_SIGNAL_0;
+
+	      target_resume (pid, 0, stop_signal);
 	      continue;
 	    }
-	  else
+
+	  /* It's a SIGTRAP or a signal we're interested in.  Switch threads,
+	     and fall into the rest of wait_for_inferior().  */
+
+	  inferior_pid = pid;
+	  printf_filtered ("[Switching to %s]\n", target_pid_to_str (pid));
+
+	  flush_cached_frames ();
+	  trap_expected = 0;
+	  if (step_resume_breakpoint)
 	    {
-	      if (signal_print[stop_signal])
-		{
-		  printed = 1;
-		  target_terminal_ours_for_output ();
-		  printf_filtered ("\nProgram received signal %s, %s.\n",
-				   target_signal_to_name (stop_signal),
-				   target_signal_to_string (stop_signal));
-		  gdb_flush (gdb_stdout);
-		}
-
-	      if (stop_signal == TARGET_SIGNAL_TRAP
-		  || signal_stop[stop_signal])
-		{
-switch_thread:
-		  inferior_pid = pid;
-		  printf_filtered ("[Switching to %s]\n", target_pid_to_str (pid));
-
-		  flush_cached_frames ();
-		  registers_changed ();
-		  trap_expected = 0;
-		  if (step_resume_breakpoint)
-		    {
-		      delete_breakpoint (step_resume_breakpoint);
-		      step_resume_breakpoint = NULL;
-		    }
-
-		  /* Not sure whether we need to blow this away too,
-		     but probably it is like the step-resume
-		     breakpoint.  */
-		  if (through_sigtramp_breakpoint)
-		    {
-		      delete_breakpoint (through_sigtramp_breakpoint);
-		      through_sigtramp_breakpoint = NULL;
-		    }
-		  prev_pc = 0;
-		  prev_sp = 0;
-		  prev_func_name = NULL;
-		  step_range_start = 0;
-		  step_range_end = 0;
-		  step_frame_address = 0;
-		  handling_longjmp = 0;
-		  another_trap = 0;
-		}
-	      else
-		{
-		  if (printed)
-		    target_terminal_inferior ();
-
-		  /* Clear the signal if it should not be passed.  */
-		  if (signal_program[stop_signal] == 0)
-		    stop_signal = TARGET_SIGNAL_0;
-
-		  target_resume (pid, 0, stop_signal);
-		  continue;
-		}
+	      delete_breakpoint (step_resume_breakpoint);
+	      step_resume_breakpoint = NULL;
 	    }
+
+	  /* Not sure whether we need to blow this away too,
+	     but probably it is like the step-resume
+	     breakpoint.  */
+	  if (through_sigtramp_breakpoint)
+	    {
+	      delete_breakpoint (through_sigtramp_breakpoint);
+	      through_sigtramp_breakpoint = NULL;
+	    }
+	  prev_pc = 0;
+	  prev_sp = 0;
+	  prev_func_name = NULL;
+	  step_range_start = 0;
+	  step_range_end = 0;
+	  step_frame_address = 0;
+	  handling_longjmp = 0;
+	  another_trap = 0;
 	}
 
 #ifdef NO_SINGLE_STEP
@@ -1061,12 +1072,19 @@ switch_thread:
 	  goto keep_going;
 	}
 
+#if 1
       if (stop_func_start)
 	{
+	  struct symtab *s;
+
 	  /* Do this after the IN_SIGTRAMP check; it might give
 	     an error.  */
 	  prologue_pc = stop_func_start;
-	  SKIP_PROLOGUE (prologue_pc);
+
+	  /* Don't skip the prologue if this is assembly source */
+	  s = find_pc_symtab (stop_pc);
+	  if (s && s->language != language_asm)
+	    SKIP_PROLOGUE (prologue_pc);
 	}
 
       if ((/* Might be a non-recursive call.  If the symbols are missing
@@ -1105,6 +1123,14 @@ switch_thread:
 		 which can no longer happen here as long as the
 		 handling_longjmp stuff is working.  */
 	      ))
+#else
+/* This is experimental code which greatly simplifies the subroutine call
+   test.  I've actually tested on the Alpha, and it works great. -Stu */
+
+	if (in_prologue (stop_pc, NULL)
+	    || (prev_func_start != 0
+		&& stop_func_start == 0))
+#endif
 	{
 	  /* It's a subroutine call.  */
 
@@ -1166,7 +1192,13 @@ step_over_function:
 step_into_function:
 	  /* Subroutine call with source code we should not step over.
 	     Do step to the first line of code in it.  */
-	  SKIP_PROLOGUE (stop_func_start);
+	  {
+	    struct symtab *s;
+
+	    s = find_pc_symtab (stop_pc);
+	    if (s && s->language != language_asm)
+	      SKIP_PROLOGUE (stop_func_start);
+	  }
 	  sal = find_pc_line (stop_func_start, 0);
 	  /* Use the step_resume_break to step until
 	     the end of the prologue, even if that involves jumps
diff --git a/gdb/lynx-nat.c b/gdb/lynx-nat.c
index 49f361d..3d7c92d 100644
--- a/gdb/lynx-nat.c
+++ b/gdb/lynx-nat.c
@@ -597,7 +597,7 @@ child_wait (pid, ourstatus)
 {
   int save_errno;
   int thread;
-  int status;
+  union wait status;
 
   while (1)
     {
@@ -632,8 +632,7 @@ child_wait (pid, ourstatus)
       if (pid != PIDGET (inferior_pid))	/* Some other process?!? */
 	continue;
 
-/*      thread = WIFTID (status);*/
-      thread = status >> 16;
+      thread = status.w_tid;	/* Get thread id from status */
 
       /* Initial thread value can only be acquired via wait, so we have to
 	 resort to this hack.  */
@@ -646,7 +645,26 @@ child_wait (pid, ourstatus)
 
       pid = BUILDPID (pid, thread);
 
-      store_waitstatus (ourstatus, status);
+      if (WIFSTOPPED(status)
+	  && WSTOPSIG(status) == SIGTRAP
+	  && !in_thread_list (pid))
+	{
+	  int realsig;
+
+	  realsig = ptrace (PTRACE_GETTRACESIG, pid, 0);
+
+	  if (realsig == SIGNEWTHREAD)
+	    {
+	      /* Simply ignore new thread notification, as we can't do anything
+		 useful with such threads.  All ptrace calls at this point just
+		 fail for no apparent reason.  The thread will eventually get a
+		 real signal when it becomes real.  */
+	      child_resume (pid, 0, TARGET_SIGNAL_0);
+	      continue;
+	    }
+	}
+
+      store_waitstatus (ourstatus, status.w_status);
 
       return pid;
     }
@@ -662,13 +680,18 @@ child_resume (pid, step, signal)
      int step;
      enum target_signal signal;
 {
+  int func;
+
   errno = 0;
 
   if (pid == -1)
-    /* Resume all threads.  */
-    /* I think this only gets used in the non-threaded case, where "resume
-       all threads" and "resume inferior_pid" are the same.  */
-    pid = inferior_pid;
+    {
+      /* Resume all threads.  */
+
+      pid = inferior_pid;
+    }
+
+  func = step ? PTRACE_SINGLESTEP_ONE : PTRACE_CONT;
 
   /* An address of (PTRACE_ARG3_TYPE)1 tells ptrace to continue from where
      it was.  (If GDB wanted it to start some other way, we have already
@@ -679,12 +702,7 @@ child_resume (pid, step, signal)
      continue request (by setting breakpoints on all possible successor
      instructions), so we don't have to worry about that here.  */
 
-  if (step)
-    ptrace (PTRACE_SINGLESTEP_ONE,     pid, (PTRACE_ARG3_TYPE) 1,
-	    target_signal_to_host (signal));
-  else
-    ptrace (PTRACE_CONT_ONE, pid, (PTRACE_ARG3_TYPE) 1,
-	    target_signal_to_host (signal));
+  ptrace (func, pid, (PTRACE_ARG3_TYPE) 1, target_signal_to_host (signal));
 
   if (errno)
     perror_with_name ("ptrace");