Re: --pid and --core

[Pedro Alves <pedro@codesourcery.com>]

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Joel Brobecker wrote:
> Thanks for the patch. A couple of of comments:
> 

Thanks for taking a look!

> It took me a long while to understand this loop. I realize this was
> already implemented that way before, but I think something like the code
> below is simpler. What do you think?
> 

I completely agree.  It looks much cleaner.  Thanks.

>   if (argc - optind > 0)

I just changed these to use the (optind < argc) idiom, which is
already used in the file.

>   /* Any argument left on the command line is unexpected and will be
>      ignored.  Inform the user.  */
>   for (; optind < argc; optind++)
>     fprintf_unfiltered (...);
> 

I'm keeping the output format (ARG) or (ARG ...) if (optind < argc).

There's a wrinkle.  The 'int count' variable that was originally
used in the loop, was also used to do a last resort stack alignment in
captured_main's entry.

#if defined (ALIGN_STACK_ON_STARTUP)
      i = (int) &count & 0x03;
      if (i != 0)
        alloca (4 - i);
#endif

ALIGN_STACK_ON_STARTUP isn't defined in any target/host
anymore, and if it was, count is in the middle of the stack frame
for long and nobody complained.  We can safely
remove it.  It's mentioned in the gdbint manual, so that'll
go too.

Now with correct email in the ChangeLog entry ...

Retested on i686-pc-linux-gnu.

OK ?

Eli, gdbint patch OK ?

-- 
Pedro Alves




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2008-01-03  Pedro Alves  <pedro@codesourcery.com>

	gdb/

	* main.c (captured_main): Remove 'count' varible and the
	ALIGN_STACK_ON_ENTRY block that used it.  Error out if --core and
	--pid options were issued simultaneously.  If an explicit pid
	option was passed, don't fallback to core file.  Detect extra
	arguments better in the presence of explicit pid or core
	arguments.

2008-01-03  Pedro Alves  <pedro@codesourcery.com>

	gdb/doc/

	* gdbint.texinfo (Host Conditionals): Remove mention of
	ALIGN_STACK_ON_ENTRY.

---
 gdb/doc/gdbint.texinfo |    7 ---
 gdb/main.c             |   88 +++++++++++++++++++++++++++----------------------
 2 files changed, 50 insertions(+), 45 deletions(-)

Index: src/gdb/main.c
===================================================================
--- src.orig/gdb/main.c	2008-01-02 17:58:39.000000000 +0000
+++ src/gdb/main.c	2008-01-04 11:36:05.000000000 +0000
@@ -119,7 +119,6 @@ captured_main (void *data)
   struct captured_main_args *context = data;
   int argc = context->argc;
   char **argv = context->argv;
-  int count;
   static int quiet = 0;
   static int batch = 0;
   static int set_args = 0;
@@ -127,7 +126,9 @@ captured_main (void *data)
   /* Pointers to various arguments from command line.  */
   char *symarg = NULL;
   char *execarg = NULL;
+  char *pidarg = NULL;
   char *corearg = NULL;
+  char *pid_or_core_arg = NULL;
   char *cdarg = NULL;
   char *ttyarg = NULL;
 
@@ -175,12 +176,6 @@ captured_main (void *data)
   lim_at_start = (char *) sbrk (0);
 #endif
 
-#if defined (ALIGN_STACK_ON_STARTUP)
-  i = (int) &count & 0x3;
-  if (i != 0)
-    alloca (4 - i);
-#endif
-
   cmdsize = 1;
   cmdarg = (struct cmdarg *) xmalloc (cmdsize * sizeof (*cmdarg));
   ncmd = 0;
@@ -435,8 +430,7 @@ captured_main (void *data)
 	    corearg = optarg;
 	    break;
 	  case 'p':
-	    /* "corearg" is shared by "--core" and "--pid" */
-	    corearg = optarg;
+	    pidarg = optarg;
 	    break;
 	  case 'x':
 	    cmdarg[ncmd].type = CMDARG_FILE;
@@ -572,26 +566,34 @@ extern int gdbtk_test (char *);
       }
     else
       {
-	/* OK, that's all the options.  The other arguments are filenames.  */
-	count = 0;
-	for (; optind < argc; optind++)
-	  switch (++count)
-	    {
-	    case 1:
-	      symarg = argv[optind];
-	      execarg = argv[optind];
-	      break;
-	    case 2:
-	      /* The documentation says this can be a "ProcID" as well. 
-	         We will try it as both a corefile and a pid.  */
-	      corearg = argv[optind];
-	      break;
-	    case 3:
-	      fprintf_unfiltered (gdb_stderr,
-				  _("Excess command line arguments ignored. (%s%s)\n"),
-				  argv[optind], (optind == argc - 1) ? "" : " ...");
-	      break;
-	    }
+	/* OK, that's all the options.  */
+
+	/* The first argument, if specified, is the name of the
+	   executable.  */
+	if (optind < argc)
+	  {
+	    symarg = argv[optind];
+	    execarg = argv[optind];
+	    optind++;
+	  }
+
+	/* If the user hasn't already specified a PID or the name of a
+	   core file, then a second optional argument is allowed.  If
+	   present, this argument should be interpreted as either a
+	   PID or a core file, whichever works.  */
+	if (pidarg == NULL && corearg == NULL && optind < argc)
+	  {
+	    pid_or_core_arg = argv[optind];
+	    optind++;
+	  }
+
+	/* Any argument left on the command line is unexpected and
+	   will be ignored.  Inform the user.  */
+	if (optind < argc)
+	  fprintf_unfiltered (gdb_stderr, _("\
+Excess command line arguments ignored. (%s%s)\n"),
+			      argv[optind],
+			      (optind == argc - 1) ? "" : " ...");
       }
     if (batch)
       quiet = 1;
@@ -733,21 +735,31 @@ extern int gdbtk_test (char *);
 	catch_command_errors (symbol_file_add_main, symarg, 0, RETURN_MASK_ALL);
     }
 
+  if (corearg && pidarg)
+    error (_("\
+Can't attach to process and specify a core file at the same time."));
+
   if (corearg != NULL)
-    {
-      /* corearg may be either a corefile or a pid.
-	 If its first character is a digit, try attach first
-	 and then corefile.  Otherwise try corefile first. */
+    catch_command_errors (core_file_command, corearg,
+			  !batch, RETURN_MASK_ALL);
+  else if (pidarg != NULL)
+    catch_command_errors (attach_command, pidarg,
+			  !batch, RETURN_MASK_ALL);
+  else if (pid_or_core_arg)
+    {
+      /* The user specified 'gdb program pid' or gdb program core'.
+	 If pid_or_core_arg's first character is a digit, try attach
+	 first and then corefile.  Otherwise try just corefile.  */
 
-      if (isdigit (corearg[0]))
+      if (isdigit (pid_or_core_arg[0]))
 	{
-	  if (catch_command_errors (attach_command, corearg, 
+	  if (catch_command_errors (attach_command, pid_or_core_arg,
 				    !batch, RETURN_MASK_ALL) == 0)
-	    catch_command_errors (core_file_command, corearg, 
+	    catch_command_errors (core_file_command, pid_or_core_arg,
 				  !batch, RETURN_MASK_ALL);
 	}
-      else /* Can't be a pid, better be a corefile. */
-	catch_command_errors (core_file_command, corearg, 
+      else /* Can't be a pid, better be a corefile.  */
+	catch_command_errors (core_file_command, pid_or_core_arg,
 			      !batch, RETURN_MASK_ALL);
     }
 
Index: src/gdb/doc/gdbint.texinfo
===================================================================
--- src.orig/gdb/doc/gdbint.texinfo	2008-01-04 11:35:30.000000000 +0000
+++ src/gdb/doc/gdbint.texinfo	2008-01-04 11:35:51.000000000 +0000
@@ -2490,13 +2490,6 @@ of a function to be called if @code{SIGW
 Define this to expand into code that will define the function named by
 the expansion of @code{SIGWINCH_HANDLER}.
 
-@item ALIGN_STACK_ON_STARTUP
-@cindex stack alignment
-Define this if your system is of a sort that will crash in
-@code{tgetent} if the stack happens not to be longword-aligned when
-@code{main} is called.  This is a rare situation, but is known to occur
-on several different types of systems.
-
 @item CRLF_SOURCE_FILES
 @cindex DOS text files
 Define this if host files use @code{\r\n} rather than @code{\n} as a