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Re: Please help get me started...

To: Robert Lewko <rob at wirelessnetworksinc dot com>
Subject: Re: Please help get me started...
From: Kai Ruottu <kai dot ruottu at luukku dot com>
Date: Sat, 07 Apr 2001 02:01:11 +0300
CC: crossgcc at sourceware dot cygnus dot com
Organization: Freenet Finland
References: <3ACD0206.6FA60F8D@wirelessnetworksinc.com>
Reply-To: karuottu at freenet dot hut dot fi

Robert Lewko wrote:
> 
> First, let me see if I am on the right track.  What I eventually want is
> a c/c++ compiler that is hosted on i386-linux and generates code for
> arm-linux-elf and links against the uC-libc library.  This library
> should include the linux-threads package.  Do I build a cross compiler
> first with newlib then use that to compile uC-libc or can I start
> building the compiler wiith uC-libc.

 I cannot imagine any reason using newlib in the build... Just go into the:

     http://www.uClinux.org/pub/uClinux/ports

and download the uC-libc sources for ARM, then copy the headers from it into
the proper place and start building GCC...  About the linux-threads I'm not
sure, there was a preliminary glibc-port in www.uClinux.org, don't remember
the linux-threads mentioned with uC-libc, but perhaps it can be glued into
it somehow....

> What I am trying to do is build a gcc cross compiler hosted on a
> i386-intel machine running linux and cross compiling to
> target=arm-linux-elf.

 ?????  The target name is 'arm-uclinux', not the 'arm-linux' or 'arm-elf'.
Basically the configuration is the same as for 'arm-linux-gnu', but the
library names etc. are different. Someone wrote some misleading info on this
list a week or so ago but everyone is free to believe or not and I'm too old
and tired to argue...

> I have read the CrossGcc FAQ.  I have run the
> one-tree-1.6.sh with binutils-2.10.tar.gz,  gcc-2.95.tar.gz and
> newlib-1.9.0.tar.gz in the tars directory.

 As said, don't use newlib. And gcc-2.95.2 needs the uClinux patches (they were
broken when I last looked at the www.uClinux.org... I used the RedHat-EDK sources
instead, there the 'arm-uclinux' and 'thumb-uclinux' targets were already known
and the needed config files included...

> 3) make ~/crossgcc/build
> 
> 4) enter this directory and issue the command:
> 
> ../src/configure --target=arm-linux --with-newlib
> 
> 5) make all
> 
> This stops with an error as follows:
> 
> cp ../../src/gcc/config/arm/lib1funcs.asm libgcc1.S
> for name in _udivsi3 _divsi3 _umodsi3 _modsi3 _dvmd_lnx; \
> do \
>   echo ${name}; \
>   /home/rob/crosscompiler/build/gcc/xgcc
> -B/home/rob/crosscompiler/build/gcc/ -B/usr/local/arm-linux/bin/
> -I/usr/local/arm-linux/include -O2  -DCROSS_COMPILE -DIN_GCC     -g -O2
> -I./include  -fomit-frame-pointer -fPIC -g0 -DHAVE_GTHR_DEFAULT
> -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -Dinhibit_libc  -I.
> -I../../src/gcc -I../../src/gcc/config -I../../src/gcc/../include -c
> -DL${name} libgcc1.S; \
>   if [ $? -eq 0 ] ; then true; else exit 1; fi; \
>   mv libgcc1.o ${name}.o; \
>   /home/rob/crosscompiler/build/binutils/ar rc tmplibgcc1.a ${name}.o; \
> 
>   rm -f ${name}.o; \
> done
> _udivsi3
> _divsi3
> _umodsi3
> _modsi3
> _dvmd_lnx
> libgcc1.S:438: asm/unistd.h: No such file or directory
> make[1]: *** [libgcc1-asm.a] Error 1

 When you selected a Linux-target, Linux-stuff you must have...

> I have noticed that there are much newer compilers, ie.
> gcc-2.95.3.tar.gz.  Should I use this one?  If not what have I done
> wrong?

 The gcc-2.95.x-branch would be ok, if only the patches would be there...
Basically only some small files are needed and the entry into 'gcc/configure'
plus fixes into 'config.sub' so that the target will be recognized...

--------------------- clip ------------------------------------------
		case x${enable_threads} in
		x | xyes | xpthreads | xposix)
			thread_file='posix'
			;;
		esac
		;;
+	arm*-*-uclinux*)		# ARM ucLinux
+		tm_file=arm/uclinux-elf.h
+		tmake_file=arm/t-arm-uclinux
+		;;
	arm*-*-aout)
		tm_file=arm/aout.h
		tmake_file=arm/t-bare
		;;
        arm*-*-ecos-elf)
		tm_file=arm/ecos-elf.h
		tmake_file=arm/t-elf
		;; 
--------------------- clip ------------------------------------------

 Just a piece of cake if one has any clue about what to do. My config
files and the 'mno-got' patch are attached here but I haven't yet tried
these with gcc-2.95.3... The gcc-3.0 prerelease has the 'arm-uclinux'
somehow supported but no clue about the availability of the 'mno-got'
option... I suggest looking at the www.uClinux.org documents, browsing
the messages on the uClinux-maillist and so on...

 Only you will know what library variations you will need, so the MULTILIB
definitions in 't-arm-uclinux' are just examples...

Cheers, Kai

uclinux-elf.h

CROSS_LIBGCC1 = libgcc1-asm.a
LIB1ASMSRC = arm/lib1funcs.asm
LIB1ASMFUNCS = _udivsi3 _divsi3 _umodsi3 _modsi3 _dvmd_tls _call_via_rX

# We want fine grained libraries, so use the new code to build the
# floating point emulation libraries.
FPBIT = fp-bit.c
DPBIT = dp-bit.c

fp-bit.c: $(srcdir)/config/fp-bit.c
	echo '#define FLOAT' > fp-bit.c
	echo '#ifndef __ARMEB__' >> fp-bit.c
	echo '#define FLOAT_BIT_ORDER_MISMATCH' >> fp-bit.c
	echo '#endif' >> fp-bit.c
	cat $(srcdir)/config/fp-bit.c >> fp-bit.c

dp-bit.c: $(srcdir)/config/fp-bit.c
	echo '#ifndef __ARMEB__' > dp-bit.c
	echo '#define FLOAT_BIT_ORDER_MISMATCH' >> dp-bit.c
	echo '#define FLOAT_WORD_ORDER_MISMATCH' >> dp-bit.c
	echo '#endif' >> dp-bit.c
	cat $(srcdir)/config/fp-bit.c >> dp-bit.c

MULTILIB_OPTIONS     = mlittle-endian/mbig-endian
MULTILIB_DIRNAMES    = le be
MULTILIB_EXCEPTIONS  = 
MULTILIB_MATCHES     = mbig-endian=mbe mlittle-endian=mle

MULTILIB_OPTIONS    += mhard-float/msoft-float
MULTILIB_DIRNAMES   += fpu soft

MULTILIB_OPTIONS    += mcpu=arm7
MULTILIB_DIRNAMES   += nofmult

# We have to match all the arm cpu variants which do not have the
# multiply instruction and treat them as if the user had specified
# -mcpu=arm7.  Note that in the following the ? is interpreted as
# an = for the purposes of matching command line options.
# FIXME: There ought to be a better way to do this.

MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm7d
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm7di
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm70
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm700
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm700i
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm710
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm710c
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm7100
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm7500
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm7500fe
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm6
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm60
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm600
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm610
MULTILIB_MATCHES    += mcpu?arm7=mcpu?arm620
 
EXTRA_MULTILIB_PARTS = crtbegin.o crtend.o
LIBGCC               = stmp-multilib
INSTALL_LIBGCC       = install-multilib

TARGET_LIBGCC2_CFLAGS = -Dinhibit_libc


Patch for arm-uclinux target
the patch allows generation of Position Independent Code not using GOT and
PLT relocations
when gcc is configured for arm-uclinux target.  arm-uclinux-gcc will enter
this mode when given -mno-got option

ChangeLog

2000-01-08  Vadim Lebedev <vlebedev@aplio.fr>

  *  config.sub          Added arm-uclinux target
  *  gcc/Configure   modified arm-uclinux-target to use t-arm-uclinux
fragment
  *  gcc/config/arm/arm.c added usage of ARM_SUBTARGET_OVERRIDE_OPTION in
                                arm_override_options
                                arm_legitimize_pic_address modified to
generate indirection throug
                                GOT ONLY if NEED_GOT_RELOC is true

  *   gcc/config/arm/arm.h  added define ARM_FLAG_LAST_USED_BIT to specify
last used bit
                                in target_flags

  *  gcc/config/arm/uclinux-elf.h  modified to support -mno-got option


Index: config.sub
===================================================================
RCS file: /cvs/gcc/egcs/config.sub,v
retrieving revision 1.37
diff -c -r1.37 config.sub
*** config.sub 1999/12/14 16:10:58 1.37
--- config.sub 2000/01/07 13:02:13
***************
*** 920,926 ****
         | -udi* | -eabi* | -lites* | -ieee* | -go32* | -aux* \
         | -cygwin* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
         | -mingw32* | -linux-gnu* | -uxpv* | -beos* | -mpeix* | -udk* \
!        | -interix* | -uwin* | -rhapsody* | -opened* | -openstep*
| -oskit*)
   # Remember, each alternative MUST END IN *, to match a version number.
    ;;
   -sim | -es1800* | -hms* | -xray | -os68k* | -none* | -v88r* \
--- 920,928 ----
         | -udi* | -eabi* | -lites* | -ieee* | -go32* | -aux* \
         | -cygwin* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
         | -mingw32* | -linux-gnu* | -uxpv* | -beos* | -mpeix* | -udk* \
!        | -interix* | -uwin* | -rhapsody* | -openstep* | -oskit* \
!     | -uclinux* )
!
   # Remember, each alternative MUST END IN *, to match a version number.
    ;;
   -sim | -es1800* | -hms* | -xray | -os68k* | -none* | -v88r* \
Index: gcc/configure
===================================================================
RCS file: /cvs/gcc/egcs/gcc/configure,v
retrieving revision 1.317
diff -c -r1.317 configure
*** configure 2000/01/05 08:23:15 1.317
--- configure 2000/01/07 13:02:15
***************
*** 3620,3626 ****
    ;;
   arm*-*-uclinux*)  # ARM ucLinux
    tm_file=arm/uclinux-elf.h
!   tmake_file=arm/t-arm-elf
    ;;
   arm*-*-aout)
    tm_file=arm/aout.h
--- 3620,3627 ----
    ;;
   arm*-*-uclinux*)  # ARM ucLinux
    tm_file=arm/uclinux-elf.h
!   tmake_file=arm/t-arm-uclinux
!   extra_parts="crtbegin.o crtbeginS.o crtend.o crtendS.o"
    ;;
   arm*-*-aout)
    tm_file=arm/aout.h
Index: gcc/config/arm/arm.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/config/arm/arm.c,v
retrieving revision 1.74
diff -c -r1.74 arm.c
*** arm.c 1999/12/14 19:42:58 1.74
--- arm.c 2000/01/07 13:02:17
***************
*** 288,294 ****
  arm_override_options ()
  {
    unsigned i;
!
    /* Set up the flags based on the cpu/architecture selected by the user.
*/
    for (i = sizeof (arm_select) / sizeof (arm_select[0]); i--;)
      {
--- 288,299 ----
  arm_override_options ()
  {
    unsigned i;
!
! #ifdef ARM_SUBTARGET_OVERRIDE_OPTIONS
!
!   ARM_SUBTARGET_OVERRIDE_OPTIONS ;
!
! #endif
    /* Set up the flags based on the cpu/architecture selected by the user.
*/
    for (i = sizeof (arm_select) / sizeof (arm_select[0]); i--;)
      {
***************
*** 1525,1534 ****

        emit_insn (gen_pic_load_addr (address, orig));

!       pic_ref = gen_rtx_MEM (Pmode,
!         gen_rtx_PLUS (Pmode, pic_offset_table_rtx,
!         address));
!       RTX_UNCHANGING_P (pic_ref) = 1;
        insn = emit_move_insn (reg, pic_ref);
  #endif
        current_function_uses_pic_offset_table = 1;
--- 1530,1544 ----

        emit_insn (gen_pic_load_addr (address, orig));

!    pic_ref = gen_rtx_PLUS (Pmode, pic_offset_table_rtx,
!          address);
!
!    if (NEED_GOT_RELOC)
!    {
!     pic_ref = gen_rtx_MEM (Pmode, pic_ref);
!     RTX_UNCHANGING_P (pic_ref) = 1;
!    }
!
        insn = emit_move_insn (reg, pic_ref);
  #endif
        current_function_uses_pic_offset_table = 1;
***************
*** 6041,6047 ****
   if (regs_ever_live[reg] && ! call_used_regs[reg])
     live_regs_mask |= 1 << reg;

!       if (flag_pic && regs_ever_live[PIC_OFFSET_TABLE_REGNUM])
   live_regs_mask |= 1 << PIC_OFFSET_TABLE_REGNUM;

        if (regs_ever_live[LR_REGNUM])
--- 6051,6058 ----
   if (regs_ever_live[reg] && ! call_used_regs[reg])
     live_regs_mask |= 1 << reg;

!    if (flag_pic && ! TARGET_SINGLE_PIC_BASE
!     && regs_ever_live[PIC_OFFSET_TABLE_REGNUM])
   live_regs_mask |= 1 << PIC_OFFSET_TABLE_REGNUM;

        if (regs_ever_live[LR_REGNUM])
Index: gcc/config/arm/arm.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/config/arm/arm.h,v
retrieving revision 1.56
diff -c -r1.56 arm.h
*** arm.h 1999/12/14 19:42:58 1.56
--- arm.h 2000/01/07 13:02:18
***************
*** 318,323 ****
--- 318,327 ----
  /* Nonzero if all call instructions should be indirect.  */
  #define ARM_FLAG_LONG_CALLS (1 << 15)

+ /* last used bit in target_flags */
+ #define ARM_FLAG_LAST_USED_BIT 15
+
+
  #define TARGET_APCS   (target_flags & ARM_FLAG_APCS_FRAME)
  #define TARGET_POKE_FUNCTION_NAME (target_flags & ARM_FLAG_POKE)
  #define TARGET_FPE   (target_flags & ARM_FLAG_FPE)
***************
*** 335,341 ****
  #define TARGET_ABORT_NORETURN  (target_flags & ARM_FLAG_ABORT_NORETURN)
  #define TARGET_SINGLE_PIC_BASE  (target_flags & ARM_FLAG_SINGLE_PIC_BASE)
  #define TARGET_LONG_CALLS  (target_flags & ARM_FLAG_LONG_CALLS)
!
  /* SUBTARGET_SWITCHES is used to add flags on a per-config basis.
     Bit 31 is reserved.  See riscix.h.  */
  #ifndef SUBTARGET_SWITCHES
--- 339,345 ----
  #define TARGET_ABORT_NORETURN  (target_flags & ARM_FLAG_ABORT_NORETURN)
  #define TARGET_SINGLE_PIC_BASE  (target_flags & ARM_FLAG_SINGLE_PIC_BASE)
  #define TARGET_LONG_CALLS  (target_flags & ARM_FLAG_LONG_CALLS)
!
  /* SUBTARGET_SWITCHES is used to add flags on a per-config basis.
     Bit 31 is reserved.  See riscix.h.  */
  #ifndef SUBTARGET_SWITCHES
Index: gcc/config/arm/uclinux-elf.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/config/arm/uclinux-elf.h,v
retrieving revision 1.3
diff -c -r1.3 uclinux-elf.h
*** uclinux-elf.h 1999/12/18 13:34:21 1.3
--- uclinux-elf.h 2000/01/07 13:02:18
***************
*** 1,7 ****
  /* Definitions for ARM running ucLinux using ELF
     Copyright (C) 1999 Free Software Foundation, Inc.
     Contributed by Philip Blundell <pb@nexus.co.uk>
!
  This file is part of GNU CC.

  GNU CC is free software; you can redistribute it and/or modify
--- 1,8 ----
  /* Definitions for ARM running ucLinux using ELF
     Copyright (C) 1999 Free Software Foundation, Inc.
     Contributed by Philip Blundell <pb@nexus.co.uk>
!    Modified by Vadim Lebedev <vlebedev@aplio.fr>
!
  This file is part of GNU CC.

  GNU CC is free software; you can redistribute it and/or modify
***************
*** 21,32 ****

  #include "arm/linux-elf.h"

  /* We don't want a PLT.  */
  #undef  NEED_PLT_RELOC
  #define NEED_PLT_RELOC 0

  #undef  TARGET_VERSION
  #define TARGET_VERSION fputs (" (ARM/ELF ucLinux)", stderr);

  #undef  TARGET_DEFAULT
! #define TARGET_DEFAULT (ARM_FLAG_APCS_32 | ARM_FLAG_MMU_TRAPS |
ARM_FLAG_SINGLE_PIC_BASE)
--- 22,50 ----

  #include "arm/linux-elf.h"

+ #define ARM_FLAG_NO_GOT  (1 << (ARM_FLAG_LAST_USED_BIT+1))
+ #define TARGET_NO_GOT (target_flags & ARM_FLAG_NO_GOT)
+
+ #undef SUBTARGET_SWITCHES
+ #define SUBTARGET_SWITCHES \
+  {"got",    -ARM_FLAG_NO_GOT, ""}, \
+  {"no-got",    ARM_FLAG_NO_GOT, \
+  "Do not use GOT relocations" }, \
+
+ /* -mno-got will force -fPIC -msingle-pic-base */
+ #define ARM_SUBTARGET_OVERRIDE_OPTIONS  if (TARGET_NO_GOT) { flag_pic = 2;
target_flags |= ARM_FLAG_SINGLE_PIC_BASE; }
+
  /* We don't want a PLT.  */
  #undef  NEED_PLT_RELOC
  #define NEED_PLT_RELOC 0

+ #undef  NEED_GOT_RELOC
+ #define NEED_GOT_RELOC (flag_pic && !TARGET_NO_GOT)
+
+
  #undef  TARGET_VERSION
  #define TARGET_VERSION fputs (" (ARM/ELF ucLinux)", stderr);

  #undef  TARGET_DEFAULT
! #define TARGET_DEFAULT (ARM_FLAG_APCS_32 | ARM_FLAG_MMU_TRAPS )
!

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Follow-Ups:
- Re: Please help get me started...
  - From: Philip Blundell

References:
- Please help get me started...
  - From: Robert Lewko

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