Cfront bootstrap on a year-2014-ish Linux.
Generation of the compiler binaries.
No warranties.
2015-05-16

Copyright (C) 2014, 2015 RL @ Aetey Global Technologies AB

LICENSE: BSD 2-clause.

This description is manually derived from a formal procedure which is
specific to the author's build environment. Adjust for your situation.

Assuming cfront 3.0.3 sources, which seem to exist in a single (partly
broken) incarnation, licensed for computer history research:
http://www.softwarepreservation.org/projects/c_plus_plus/cfront/release_3.0.3/source/cfront_3_0_3.tgz

The author used pcc-1.1.0+ as the target C compiler and g++ 4.2.3 for
bootstrapping which was carried out on ia32.

Assuming reader proficiency in unix scripting and C.
Using below leading space to indicate comments/directions,
 actual commands when shown start at the beginning of the line.

 Unpack.

 Rename to get rid of the space in "C++ 3.0.3" :)

cd C++3.0.3/source

 For clarity/generality we preserve and use the original copy,
 identically patching twice below, instead a single patch application
 would suffice before doing this copy.
cp -a src src.ori

 Collect the knowledge about the C-environment:
 Patch szal for long long (the patch is not included here)
cc -o szal szal.c
./szal >szal.result

cd src
chmod u+w *

 Apply the "long long" patch (the patch is not included here)

 cfront.h: insert "#include <cstdlib>"
 template.h: comment out "enum bool",
             replace "typename" member name with a different word
 template.c: replace "typename" member name with the different word
 dcl.c: put parentheses around "new texpr(G_CAST,nt,init)"
 expr2.c: insert "extern Pname has_templ_instance(Pname, Pexpr, bit);"
 expr3.c: insert "extern Pname has_templ_instance(Pname, Pexpr, bit);"
 hash.c: insert "#include <cstdlib>"
 main.c: comment out "#include <libc.h>", "#include <osfcn.h>",
         lines with SIGEMT
 tree_copy.c: replace member name "ia" with some other word

 generate y.tab.c with heirloom yacc (or ask someone who can do this for you)

 Prepare some extra headers in a separate directory:
 generic.h:
 ----
#ifndef GENERICH
#define GENERICH 1

#define name2(a,b)      _name2_aux(a,b)
#define _name2_aux(a,b)      a##b
#define name3(a,b,c)    _name3_aux(a,b,c)
#define _name3_aux(a,b,c)    a##b##c
#define name4(a,b,c,d)  _name4_aux(a,b,c,d)
#define _name4_aux(a,b,c,d)  a##b##c##d

#define declare(a,t) name2(a,declare)(t)
#define implement(a,t) name2(a,implement)(t)
#define declare2(a,t1,t2) name2(a,declare2)(t1,t2)
#define implement2(a,t1,t2) name2(a,implement2)(t1,t2)

extern int genericerror(int,char*);
typedef int (*GPT)(int,char*);

#define set_handler(generic,type,x) name4(set_,type,generic,_handler)(x)
#define errorhandler(generic,type) name3(type,generic,handler)
#define callerror(generic,type,a,b) (*errorhandler(generic,type))(a,b)

#endif
 ----
 new.h:
 ----
#ifndef __NEW_H
#define __NEW_H

#include <stddef.h>

extern void (*set_new_handler (void(*)()))();

void *operator new(size_t, void*);

#endif
 ----

make \
 CC=g++ \
 CCFLAGS="-O -fno-for-scope -fpermissive -fno-operator-names -DSYSV -I<dir>"

 We have got a minimally "working" cfront, now let it bootstrap itself.

cp cfront ..

cd ..

mv src src.patched-for-g++
cp -a src.ori/. src

cd src
chmod u+w *

 Apply the "long long" patch (the patch is not included here)

 add the same y.tab.c as mentioned above

 cfront.h: insert "#include <stdlib.h>"
 hash.c: insert "#include <stdlib.h>"
 main.c: comment out "#include <libc.h>", "#include <osfcn.h>"

cd ../scratch/src

 ########### some explanation of the choice of the arguments below:
 # cpp:
 # -Dwchar_t=long      libc does not define this type with __cplusplus
 #                     and cfront did not anticipate to builtin it
 # -U__GNUC__          __GNUC__ is predefined in pcc's cpp,
 #                     some weird gcc-related stuff can come out of libc
 #                     headers and confuse cfront, better not
 # -D__cplusplus=1     to tell the c library headers we are C++ not C
 #                     (adjust for you libc if necessary)
 # -I<libcincludes>    where the libc headers actually are
 # -I<dir>             to pick the small necessary additions not
 #                     present in the libc headers nor defined by pcc,
 #                     prepared by us above
 # cfront:
 # +L                  to use "# line ...." not the ancient "# ...."
 # +f"\$A"             to reflect the name of the source file somewhere
 #                     in the output's metainfo
 # +x../../szal.result pre-include the file defining the data sizes on
 #                     our platform
 # +a1                 use ansi-syntax in the output, not k&r

 Note you have to put the relevant paths in the script below
 (look for <.*>)

cat >myCC <<____
#!/bin/sh
# (c) 2014 RL @ Aetey Global Technologies AB
# LICENSE: BSD 2-clause

set -e

# interpret/discard all arguments besides the last one

extradefs=
while [ "\$#" -gt 1 ]; do
  case "\$1" in
  -D*) extradefs="\$extradefs \$1" ;;
  esac
  shift
done

A="\$1"

# take a simplistic approach to TEMPDIR
TEMPDIR=/tmp/CCTMP."\$\$"
trap 'rm -fr "\$TEMPDIR"; exit' 0 1 2 3 13 15
mkdir "\$TEMPDIR" || exit
tmpfile="\$TEMPDIR"/cpptmp

cpp \
  \$extradefs \
  -Dwchar_t=long \
  -U__GNUC__ \
  -D__cplusplus=1 \
  -I<libcincludes> \
  -I<dir> \
  "\$A" \
  >"\$tmpfile"

LD_LIBRARY_PATH=<gcclibsdir> ../../cfront \
  +L \
  +f"\$A" \
  +x../../szal.result \
  +a1 \
  <"\$tmpfile" \
  >"\`basename "\$A" .c\`"..c

exit
____
chmod +x myCC

 Tell make not to try to rebuild y.tab.c
touch y.tab.c

make CC=./myCC

 You get a bunch of ..c files.

cd ../lib

 Note the number of ".." below, this is correct.

chmod u+w ../../lib/new/*

 ../../lib/new/_new.c: replace "extern "C" { .... }" with "#include <stdlib.h>"
                       replace "unsigned(size)" with "size"

 ../../lib/new/_arr_map.c: insert
#ifndef BITSPERBYTE
#define BITSPERBYTE 8
#endif
#define BITS(type) (BITSPERBYTE * (int)sizeof(type))

make CC=../src/myCC
cc -O -c *..c
cc -o munch munch..o _new..o _main..o _handler..o _ctor..o

cd ../src
cc -O -c *..c
cc -o precfront \
      *..o ../lib/_vec..o ../lib/pure..o \
      ../lib/_arr_map..o ../lib/_main..o \
      ../lib/_ctor..o
nm precfront | ../lib/munch >_ctdt.c
cc -O -c _ctdt.c
cc -o cfront \
      *..o ../lib/_vec..o ../lib/pure..o \
      ../lib/_arr_map..o ../lib/_main..o \
      _ctdt.o

 This cfront is no longer related to gcc, let it recompile itself.

mv cfront cfrontA

rm *..*

 No longer the need for LD_LIBRARY_PATH.

cat >myCC <<____
#!/bin/sh
# (c) 2014 RL @ Aetey Global Technologies AB
# LICENSE: BSD 2-clause

set -e

# interpret/discard all arguments besides the last one

extradefs=
while [ "\$#" -gt 1 ]; do
  case "\$1" in
  -D*) extradefs="\$extradefs \$1" ;;
  esac
  shift
done

A="\$1"

# take a simplistic approach to TEMPDIR
TEMPDIR=/tmp/CCTMP."\$\$"
trap 'rm -fr "\$TEMPDIR"; exit' 0 1 2 3 13 15
mkdir "\$TEMPDIR" || exit
tmpfile="\$TEMPDIR"/cpptmp

cpp \
  \$extradefs \
  -Dwchar_t=long \
  -U__GNUC__ \
  -D__cplusplus=1 \
  -I<libcincludes> \
  -I<dir> \
  "\$A" \
  >"\$tmpfile"

"`pwd`"/cfrontA \
  +L \
  +f"\$A" \
  +x../../szal.result \
  +a1 \
  <"\$tmpfile" \
  >"\`basename "\$A" .c\`"..c

exit
____
chmod +x myCC

make CC=./myCC

cd ../lib

rm *..*
make CC=../src/myCC
cc -O -c *..c
cc -o munch munch..o _new..o _main..o _handler..o _ctor..o

cd ../src

cc -O -c *..c

cc -o precfront \
      *..o ../lib/_vec..o ../lib/pure..o \
      ../lib/_arr_map..o ../lib/_main..o \
      ../lib/_ctor..o

nm precfront | ../lib/munch >_ctdt.c

cc -O -c _ctdt.c

cc -o cfront \
      *..o ../lib/_vec..o ../lib/pure..o \
      ../lib/_arr_map..o ../lib/_main..o \
      _ctdt.o

 Now one more round!

mv cfront cfrontB
mv ../lib/munch ../lib/munchB

rm *..* _*
 myCC: replace "cfrontA" with "cfrontB"

make CC=./myCC
cd ../lib
make CC=../src/myCC
cc -O -c *..c
cc -o munch munch..o _new..o _main..o _handler..o _ctor..o

cmp munchB munch && echo "munch is GOOD" || FAILED_BUT_WHY

cd ../src
cc -O -c *..c
cc -o precfront \
      *..o ../lib/_vec..o ../lib/pure..o \
      ../lib/_arr_map..o ../lib/_main..o \
      ../lib/_ctor..o

nm precfront | ../lib/munch >_ctdt.c

cc -O -c _ctdt.c

cc -o cfront \
      *..o ../lib/_vec..o ../lib/pure..o \
      ../lib/_arr_map..o ../lib/_main..o \
      _ctdt.o

cmp cfrontB cfront && echo "cfront is GOOD" || FAILED_BUT_WHY

cd tools/demangler

 dem.c: insert
#include <string.h>
#include <stdlib.h>

make

 Got c++filt.

 Compilation of the libraries and adjustments to the CC front end driver
 are not covered here.