Single-executable patch

Single-executable patch

[Mikhail Teterin]

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It seems, all three of the gdb, gdbtui, and insight executables are the same 
except for their (tiny) main() functions.

The attached sample patch allows to install just the gdb and link it to gdbtui 
and insight -- the program will behave differently depending on the name, 
under which it is invoked.

This saves not only the disk space (3.2Mb per executable here on FreeBSD/amd64 
despite using shared -ltcl, -ltk, -litcl, and -litk), but the more precious 
RAM at runtime too -- when different users run different interfaces on a 
shared system, the OS will be able to efficiently share the read-only pages 
between them.

Yours,

	-mi

[-- Attachment #2: patch-unified --]
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--- gdb/gdb.c	Thu Feb 13 13:07:24 2003
+++ gdb/gdb.c	Wed May 17 00:24:39 2006
@@ -23,4 +23,5 @@
 #include "gdb_string.h"
 #include "interps.h"
+#include <libgen.h>
 
 int
@@ -31,6 +32,14 @@
   args.argc = argc;
   args.argv = argv;
-  args.use_windows = 0;
-  args.interpreter_p = INTERP_CONSOLE;
+  if (strncmp(basename(argv[0]), "insight", 7) == 0) {
+    args.use_windows = 1;
+    args.interpreter_p = "insight";
+  } else if (strncmp(basename(argv[0]), "gdbtui", 6) == 0) {
+    args.use_windows = 0;
+    args.interpreter_p = INTERP_TUI;
+  } else {
+    args.use_windows = 0;
+    args.interpreter_p = INTERP_CONSOLE;
+  }
   return gdb_main (&args);
 }

Re: Single-executable patch

[Daniel Jacobowitz]

On Wed, May 17, 2006 at 03:02:18PM -0400, Mikhail Teterin wrote:
> It seems, all three of the gdb, gdbtui, and insight executables are the same 
> except for their (tiny) main() functions.
> 
> The attached sample patch allows to install just the gdb and link it to gdbtui 
> and insight -- the program will behave differently depending on the name, 
> under which it is invoked.
> 
> This saves not only the disk space (3.2Mb per executable here on FreeBSD/amd64 
> despite using shared -ltcl, -ltk, -litcl, and -litk), but the more precious 
> RAM at runtime too -- when different users run different interfaces on a 
> shared system, the OS will be able to efficiently share the read-only pages 
> between them.

This has been a world of trouble for other programs in the past, and I
do not recommend it; we switched to the separate main programs
deliberately IIRC.

If this is all you want, here's a simple implementation:

/usr/bin/gdbtui:
#!/usr/bin/gdb -i=tui

-- 
Daniel Jacobowitz
CodeSourcery

Re: Single-executable patch

[Mikhail Teterin]

ц⌠ц┘ц▓ц┘ц└ц│ 17 ц■ц▓ц│ц≈ц┘ц▌ц≤ 2006 15:07, Daniel Jacobowitz ц▌ц│ц░ц┴ц⌠ц│ц≈:
> This has been a world of trouble for other programs in the past,

I wonder, what kind of trouble?

> and I do not recommend it; we switched to the separate main programs
> deliberately IIRC.

The current main() functions are almost "too simple" now -- may it be, that 
something like my patch is *no longer* troublesome?

> If this is all you want, here's a simple implementation:
>
> /usr/bin/gdbtui:
> #!/usr/bin/gdb -i=tui

Cool! I wonder, why even bother linking other executables... It would make 
sense to do it, if, for example, the gdb was not linking with Tcl and 
friends, but it does anyway...

Thanks!

	-mi

Re: Single-executable patch

[Daniel Jacobowitz]

On Wed, May 17, 2006 at 03:27:35PM -0400, Mikhail Teterin wrote:
> ?????? 17 ??????? 2006 15:07, Daniel Jacobowitz ???????:
> > This has been a world of trouble for other programs in the past,
> 
> I wonder, what kind of trouble?

Portability.  There are many other platforms out there and many of them
are very strange...

> > If this is all you want, here's a simple implementation:
> >
> > /usr/bin/gdbtui:
> > #!/usr/bin/gdb -i=tui
> 
> Cool! I wonder, why even bother linking other executables... It would make 
> sense to do it, if, for example, the gdb was not linking with Tcl and 
> friends, but it does anyway...

It's easier if you only want one of them, and if you aren't installing
in fixed paths.  Portably locating the invoked shell script is also a
bit tricky.

-- 
Daniel Jacobowitz
CodeSourcery

Re: Single-executable patch

[Eli Zaretskii]

> From: Mikhail Teterin <mi+mx@aldan.algebra.com>
> Date: Wed, 17 May 2006 15:02:18 -0400
> 
> It seems, all three of the gdb, gdbtui, and insight executables are the same 
> except for their (tiny) main() functions.
> 
> The attached sample patch allows to install just the gdb and link it to gdbtui 
> and insight -- the program will behave differently depending on the name, 
> under which it is invoked.

This is against the GNU coding standards.  From standards.info:

    Please don't make the behavior of a utility depend on the name used to
    invoke it.  It is useful sometimes to make a link to a utility with a
    different name, and that should not change what it does.

       Instead, use a run time option or a compilation switch or both to
    select among the alternate behaviors.