diff mbox

Split up toplevel library-disabling cases

Message ID Pine.LNX.4.64.1103312337050.14316@digraph.polyomino.org.uk
State New
Headers show

Commit Message

Joseph Myers March 31, 2011, 11:40 p.m. UTC 
This patch, relative to a tree with
<http://gcc.gnu.org/ml/gcc-patches/2011-03/msg02027.html> (pending
review) applied, continues toplevel configure cleanup by splitting the
disabling of some libraries into separate case statements for those
libraries.  Separating the logic like this brings things closer to the
desired state of this configuration being in fragments in
subdirectories rather than hardcoded directly in the toplevel
configure script, as well as making it easier to clean up this logic
where the directory disabling is not in fact appropriate.

Specifically, this separates out code for target-libssp,
target-libiberty, target-libstdc++-v3 and Fortran, so covering all GCC
target-library or language disabling except that related to Java
(which is most in need of cleanup, but also the most complicated and
so best dealt with separately).

The logic for what is disabled where is kept unchanged - including the
peculiar logic for target-libiberty (sometimes skipdirs is set or
appended to, sometimes noconfigdirs) - where I think the right fix
will end up being removing target-libiberty support completely, but
don't plan to work on that.  The only changes to what would be
disabled where are: two cases, for ip2k-*-* and picochip-*-*, that
disable target-libiberty are moved completely to the separate case
statement (rather than leaving empty cases behind), so in the general
case statement those targets will now fall through to *-*-* and
disable libgcj, which is OK since ip2k-*-* has no GCC support at all
and picochip has no libffi port so can't actually build Java; in the
libstdc++-v3 case statement, the target pattern for disabling
libstdc++-v3 on WinCE was adjusted to match exactly GCC's supported
targets for CE.

OK to commit (both the previous patch this is based on, and this one)?

Target maintainers: I'd like to understand why it is necessary to
disable libssp for AVR, AIX and Microblaze, and libstdc++-v3 for AVR
(and what use C++ is on AVR without libstdc++-v3 - do you use another
C++ library?).  Note that changing libstdc++-v3/acinclude.m4 to build
only freestanding libraries for a target may be an alternative to
disabling libstdc++-v3 completely for that system.  If the libraries
don't need disabling, they shouldn't be disabled, to keep down the
amount of ad hoc tests for particular targets at toplevel.  If they do
need disabling, there should be comments to explain why.

2011-03-31  Joseph Myers  <joseph@codesourcery.com>

	* configure.ac: Separate cases disabling target-libssp,
	target-libiberty, target-libstdc++-v3 and Fortran from general
	case over targets.

Comments

Weddington, Eric April 1, 2011, 12:10 a.m. UTC | #1 
> -----Original Message-----
> From: Joseph Myers [mailto:joseph@codesourcery.com]
> Sent: Thursday, March 31, 2011 5:41 PM
> To: gcc-patches@gcc.gnu.org
> Cc: bonzini@gnu.org; dj@redhat.com; neroden@gcc.gnu.org;
> aoliva@redhat.com; Ralf.Wildenhues@gmx.de; chertykov@gmail.com;
> aesok@post.ru; Weddington, Eric; dje.gcc@gmail.com; eager@eagercon.com
> Subject: Split up toplevel library-disabling cases
> 
> Target maintainers: I'd like to understand why it is necessary to
> disable libssp for AVR, AIX and Microblaze, and libstdc++-v3 for AVR
> (and what use C++ is on AVR without libstdc++-v3 - do you use another
> C++ library?).  Note that changing libstdc++-v3/acinclude.m4 to build
> only freestanding libraries for a target may be an alternative to
> disabling libstdc++-v3 completely for that system.  If the libraries
> don't need disabling, they shouldn't be disabled, to keep down the
> amount of ad hoc tests for particular targets at toplevel.  If they do
> need disabling, there should be comments to explain why.

Hi Joseph,

Regarding the AVR port, AFAIK, it's just historical. At one point libssp didn't build for the avr, and we ended up just disabling it so users could build out of the box. I don't recall anyone seriously looked into it.

Yes, we can an do build the c++ compiler for the avr target, and we do have users using it (with an increasing number of c++ users). Again, AFAIK, libstc++-v3 has never been able to be built for the avr target, and no, we are not using another c++ library. It's been on our todo list for years to try and solve the build issues, but, as usual, it's a time and resource issue.

Bottom line is that we would eventually like to get these two build issues fixed. However, we don't even have bug reports opened up for these issues.

Eric Weddington
Ralf Wildenhues April 1, 2011, 4:04 a.m. UTC | #2 
* Joseph S. Myers wrote on Fri, Apr 01, 2011 at 01:40:47AM CEST:
> OK to commit (both the previous patch this is based on, and this one)?

Build system aspects of the patch are fine with me.

Thanks for pursuing this,
Ralf

> 2011-03-31  Joseph Myers  <joseph@codesourcery.com>
> 
> 	* configure.ac: Separate cases disabling target-libssp,
> 	target-libiberty, target-libstdc++-v3 and Fortran from general
> 	case over targets.
Joerg Wunsch April 1, 2011, 6:14 a.m. UTC | #3 
As Weddington, Eric wrote:

> > Target maintainers: I'd like to understand why it is necessary to
> > disable libssp for AVR, AIX and Microblaze, and libstdc++-v3 for AVR
> > (and what use C++ is on AVR without libstdc++-v3 - do you use another
> > C++ library?). [...]

> Regarding the AVR port, AFAIK, it's just historical. At one point
> libssp didn't build for the avr, and we ended up just disabling it
> so users could build out of the box.

IIRC, the entire SSP feature wants to write to a file, so it obviously
requires full stdio file support, including fopen() and fclose().

As the AVR port does not imply any kind of operating system (the
library is just "bare metal", sitting on top of the CPU with no
assumptions about the controller's peripherals whatsoever), there is
no file system support in avr-libc.

> Yes, we can an do build the c++ compiler for the avr target, and we
> do have users using it (with an increasing number of c++
> users). Again, AFAIK, libstc++-v3 has never been able to be built
> for the avr target, and no, we are not using another c++ library.

Last time I've been looking into it (which has been many years ago),
it somehow broke when compiling exception support, supposedly lacking
some kind of target-specific default exception handling
implementation.  That could probably be done though.  I simply stopped
then when realizing that a "Hello world!" with (faked) exception
support ended up with approximately 30 KiB of code, which was about a
quarter of the flash ROM size of the biggest AVR microcontroller
available by that time ;-), assuming nobody in AVR-land would really
want to use exceptions under those circumstances anyway.

It's possibler there's another couple of minor stumbling blocks here
as well, though I think it's nothing impossible to fix.
Michael Eager April 1, 2011, 6:37 p.m. UTC | #4 
Joseph S. Myers wrote:
> This patch, relative to a tree with
> <http://gcc.gnu.org/ml/gcc-patches/2011-03/msg02027.html> (pending
> review) applied, continues toplevel configure cleanup by splitting the
> disabling of some libraries into separate case statements for those
> libraries.  Separating the logic like this brings things closer to the
> desired state of this configuration being in fragments in
> subdirectories rather than hardcoded directly in the toplevel
> configure script, as well as making it easier to clean up this logic
> where the directory disabling is not in fact appropriate.

This sounds like a good idea.

> Target maintainers: I'd like to understand why it is necessary to
> disable libssp for AVR, AIX and Microblaze

I believe that at some time in the past libssp failed to build for
MicroBlaze, but I don't recall the details.  It currently builds
without error, so disabling it for MicroBlaze is no longer needed.
diff mbox

Patch

--- configure.ac	2011-03-29 20:32:56.000000000 +0000
+++ configure.ac.new	2011-03-31 23:21:51.000000000 +0000
@@ -516,6 +516,87 @@ 
     esac
 fi
 
+# Disable libssp for some systems.
+case "${target}" in
+  avr-*-*)
+    noconfigdirs="$noconfigdirs target-libssp"
+    ;;
+  powerpc-*-aix* | rs6000-*-aix*)
+    noconfigdirs="$noconfigdirs target-libssp"
+    ;;
+  microblaze*)
+    noconfigdirs="$noconfigdirs target-libssp"
+    ;;
+esac
+
+# Disable target libiberty for some systems.
+case "${target}" in
+  *-*-kaos*)
+    # Remove unsupported stuff on all kaOS configurations.
+    skipdirs="target-libiberty"
+    ;;
+  *-*-netbsd*)
+    # Skip some stuff on all NetBSD configurations.
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  *-*-netware*)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  *-*-rtems*)
+    skipdirs="${skipdirs} target-libiberty"
+    ;;
+  *-*-tpf*)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  *-*-vxworks*)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  sh*-*-pe|mips*-*-pe|*arm-wince-pe)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  arm*-*-symbianelf*)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  avr-*-*)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  m68hc11-*-*|m6811-*-*|m68hc12-*-*|m6812-*-*)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  picochip-*-*)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+  mips*-sde-elf*)
+    skipdirs="$skipdirs target-libiberty"
+    ;;
+  ip2k-*-*)
+    noconfigdirs="$noconfigdirs target-libiberty"
+    ;;
+esac
+
+# Disable libstdc++-v3 for some systems.
+case "${target}" in
+  *-*-vxworks*)
+    # VxWorks uses the Dinkumware C++ library.
+    noconfigdirs="$noconfigdirs target-libstdc++-v3"
+    ;;
+  arm*-wince-pe*)
+    # the C++ libraries don't build on top of CE's C libraries
+    noconfigdirs="$noconfigdirs target-libstdc++-v3"
+    ;;
+  avr-*-*)
+    noconfigdirs="$noconfigdirs target-libstdc++-v3"
+    ;;
+esac
+
+# Disable Fortran for some systems.
+case "${target}" in
+  mmix-*-*)
+    # See <http://gcc.gnu.org/ml/gcc-patches/2004-11/msg00572.html>.
+    unsupported_languages="$unsupported_languages fortran"
+    ;;
+esac
+
 # Default libgloss CPU subdirectory.
 libgloss_dir="$target_cpu"
 
@@ -562,12 +643,11 @@ 
     ;;
   *-*-kaos*)
     # Remove unsupported stuff on all kaOS configurations.
-    skipdirs="target-libiberty"
     noconfigdirs="$noconfigdirs target-libgloss"
     ;;
   *-*-netbsd*)
     # Skip some stuff on all NetBSD configurations.
-    noconfigdirs="$noconfigdirs target-newlib target-libiberty target-libgloss"
+    noconfigdirs="$noconfigdirs target-newlib target-libgloss"
 
     # Skip some stuff that's unsupported on some NetBSD configurations.
     case "${target}" in
@@ -579,21 +659,20 @@ 
     esac
     ;;
   *-*-netware*)
-    noconfigdirs="$noconfigdirs target-newlib target-libiberty target-libgloss ${libgcj}"
+    noconfigdirs="$noconfigdirs target-newlib target-libgloss ${libgcj}"
     ;;
   *-*-rtems*)
-    skipdirs="${skipdirs} target-libiberty"
     noconfigdirs="$noconfigdirs target-libgloss ${libgcj}"
     ;;
     # The tpf target doesn't support gdb yet.
   *-*-tpf*)
-    noconfigdirs="$noconfigdirs target-newlib target-libgloss target-libiberty ${libgcj} gdb tcl tk libgui itcl"
+    noconfigdirs="$noconfigdirs target-newlib target-libgloss ${libgcj} gdb tcl tk libgui itcl"
     ;;
   *-*-uclinux*)
     noconfigdirs="$noconfigdirs target-newlib target-libgloss target-rda ${libgcj}"
     ;;
   *-*-vxworks*)
-    noconfigdirs="$noconfigdirs target-newlib target-libgloss target-libiberty target-libstdc++-v3 ${libgcj}"
+    noconfigdirs="$noconfigdirs target-newlib target-libgloss ${libgcj}"
     ;;
   alpha*-dec-osf*)
     # ld works, but does not support shared libraries.
@@ -620,10 +699,7 @@ 
     ;;    
   sh*-*-pe|mips*-*-pe|*arm-wince-pe)
     noconfigdirs="$noconfigdirs ${libgcj}"
-    noconfigdirs="$noconfigdirs target-libiberty"
     noconfigdirs="$noconfigdirs tcl tk itcl libgui sim"
-    # the C++ libraries don't build on top of CE's C libraries
-    noconfigdirs="$noconfigdirs target-libstdc++-v3"
     noconfigdirs="$noconfigdirs target-newlib"
     libgloss_dir=wince
     ;;
@@ -644,7 +720,7 @@ 
     libgloss_dir=arm
     ;;
   arm*-*-symbianelf*)
-    noconfigdirs="$noconfigdirs ${libgcj} target-libiberty"
+    noconfigdirs="$noconfigdirs ${libgcj}"
     libgloss_dir=arm
     ;;
   arm-*-pe*)
@@ -654,7 +730,7 @@ 
     noconfigdirs="$noconfigdirs ld target-libgloss"
     ;;
   avr-*-*)
-    noconfigdirs="$noconfigdirs target-libiberty target-libstdc++-v3 ${libgcj} target-libssp"
+    noconfigdirs="$noconfigdirs ${libgcj}"
     ;;
   bfin-*-*)
     unsupported_languages="$unsupported_languages java"
@@ -808,7 +884,6 @@ 
     noconfigdirs="$noconfigdirs ${libgcj}"
     ;;
   m68hc11-*-*|m6811-*-*|m68hc12-*-*|m6812-*-*)
-    noconfigdirs="$noconfigdirs target-libiberty"
     libgloss_dir=m68hc11
     ;;
   m68k-*-elf*)
@@ -819,17 +894,14 @@ 
     ;;
   mmix-*-*)
     noconfigdirs="$noconfigdirs target-libffi target-boehm-gc gdb"
-    unsupported_languages="$unsupported_languages fortran java"
+    unsupported_languages="$unsupported_languages java"
     ;;
   mt-*-*)
     noconfigdirs="$noconfigdirs sim"
     ;;
-  picochip-*-*)
-    noconfigdirs="$noconfigdirs target-libiberty"
-    ;;
   powerpc-*-aix*)
     # copied from rs6000-*-* entry
-    noconfigdirs="$noconfigdirs gprof target-libgloss target-libssp target-newlib ${libgcj}"
+    noconfigdirs="$noconfigdirs gprof target-libgloss target-newlib ${libgcj}"
     ;;
   powerpc*-*-winnt* | powerpc*-*-pe*)
     target_configdirs="$target_configdirs target-winsup"
@@ -856,7 +928,7 @@ 
     noconfigdirs="$noconfigdirs target-newlib gprof ${libgcj}"
     ;;
   rs6000-*-aix*)
-    noconfigdirs="$noconfigdirs gprof target-libgloss target-libssp target-newlib ${libgcj}"
+    noconfigdirs="$noconfigdirs gprof target-libgloss target-newlib ${libgcj}"
     ;;
   rs6000-*-*)
     noconfigdirs="$noconfigdirs gprof ${libgcj}"
@@ -865,10 +937,9 @@ 
     noconfigdirs="$noconfigdirs ld binutils gprof target-libgloss"
     ;;
   microblaze*)
-    noconfigdirs="$noconfigdirs gprof target-libssp ${libgcj}"
+    noconfigdirs="$noconfigdirs gprof ${libgcj}"
     ;;
   mips*-sde-elf*)
-    skipdirs="$skipdirs target-libiberty"
     noconfigdirs="$noconfigdirs ${libgcj}"
     if test x$with_newlib = xyes; then
       noconfigdirs="$noconfigdirs gprof"
@@ -934,9 +1005,6 @@ 
   vax-*-*)
     noconfigdirs="$noconfigdirs target-newlib target-libgloss ${libgcj}"
     ;;
-  ip2k-*-*)
-    noconfigdirs="$noconfigdirs target-libiberty"
-    ;;
   *-*-linux* | *-*-gnu* | *-*-k*bsd*-gnu | *-*-kopensolaris*-gnu)
     noconfigdirs="$noconfigdirs target-newlib target-libgloss"
     ;;