2003-10-21 Arnaud Charlet <charlet@act-europe.fr>

	* 3psoccon.ads, 3veacodu.adb, 3vexpect.adb, 3vsoccon.ads,
	3vsocthi.adb, 3vsocthi.ads, 3vtrasym.adb, 3zsoccon.ads,
	3zsocthi.adb, 3zsocthi.ads, 50system.ads, 51system.ads,
	55system.ads, 56osinte.adb, 56osinte.ads, 56taprop.adb,
	56taspri.ads, 56tpopsp.adb, 57system.ads, 58system.ads,
	59system.ads, 5aml-tgt.adb, 5bml-tgt.adb, 5csystem.ads,
	5dsystem.ads, 5fosinte.adb, 5gml-tgt.adb, 5hml-tgt.adb,
	5isystem.ads, 5lparame.adb, 5msystem.ads, 5psystem.ads,
	5sml-tgt.adb, 5sosprim.adb, 5stpopsp.adb, 5tsystem.ads,
	5usystem.ads, 5vml-tgt.adb, 5vsymbol.adb, 5vtraent.adb,
	5vtraent.ads, 5wml-tgt.adb, 5xparame.ads, 5xsystem.ads,
	5xvxwork.ads, 5yparame.ads, 5ytiitho.adb, 5zinit.adb,
	5zml-tgt.adb, 5zparame.ads, 5ztaspri.ads, 5ztfsetr.adb,
	5zthrini.adb, 5ztiitho.adb, 5ztpopsp.adb, 7stfsetr.adb,
	7straces.adb, 7strafor.adb, 7strafor.ads, 7stratas.adb,
	a-excach.adb, a-exexda.adb, a-exexpr.adb, a-exextr.adb,
	a-exstat.adb, a-strsup.adb, a-strsup.ads, a-stwisu.adb,
	a-stwisu.ads, bld.adb, bld.ads, bld-io.adb,
	bld-io.ads, clean.adb, clean.ads, ctrl_c.c,
	erroutc.adb, erroutc.ads, errutil.adb, errutil.ads,
	err_vars.ads, final.c, g-arrspl.adb, g-arrspl.ads,
	g-boubuf.adb, g-boubuf.ads, g-boumai.ads, g-bubsor.adb,
	g-bubsor.ads, g-comver.adb, g-comver.ads, g-ctrl_c.ads,
	g-dynhta.adb, g-dynhta.ads, g-eacodu.adb, g-excact.adb,
	g-excact.ads, g-heasor.adb, g-heasor.ads, g-memdum.adb,
	g-memdum.ads, gnatclean.adb, gnatsym.adb, g-pehage.adb,
	g-pehage.ads, g-perhas.ads, gpr2make.adb, gpr2make.ads,
	gprcmd.adb, gprep.adb, gprep.ads, g-semaph.adb,
	g-semaph.ads, g-string.adb, g-string.ads, g-strspl.ads,
	g-wistsp.ads, i-vthrea.adb, i-vthrea.ads, i-vxwoio.adb,
	i-vxwoio.ads, Makefile.generic, Makefile.prolog, Makefile.rtl,
	prep.adb, prep.ads, prepcomp.adb, prepcomp.ads,
	prj-err.adb, prj-err.ads, s-boarop.ads, s-carsi8.adb,
	s-carsi8.ads, s-carun8.adb, s-carun8.ads, s-casi16.adb,
	s-casi16.ads, s-casi32.adb, s-casi32.ads, s-casi64.adb,
	s-casi64.ads, s-casuti.adb, s-casuti.ads, s-caun16.adb,
	s-caun16.ads, s-caun32.adb, s-caun32.ads, s-caun64.adb,
	s-caun64.ads, scng.adb, scng.ads, s-exnint.adb,
	s-exnllf.adb, s-exnlli.adb, s-expint.adb, s-explli.adb,
	s-geveop.adb, s-geveop.ads, s-hibaen.ads, s-htable.adb,
	s-htable.ads, sinput-c.adb, sinput-c.ads, s-memcop.ads,
	socket.c, s-purexc.ads, s-scaval.adb, s-stopoo.adb,
	s-strcom.adb, s-strcom.ads, s-strxdr.adb, s-rident.ads,
	s-thread.adb, s-thread.ads, s-tpae65.adb, s-tpae65.ads,
	s-tporft.adb, s-traent.adb, s-traent.ads, styleg.adb,
	styleg.ads, styleg-c.adb, styleg-c.ads, s-veboop.adb,
	s-veboop.ads, s-vector.ads, symbols.adb, symbols.ads,
	tb-alvms.c, tb-alvxw.c, tempdir.adb, tempdir.ads,
	vms_conv.ads, vms_conv.adb, vms_data.ads,
	vxaddr2line.adb: Files added. Merge with ACT tree.

	* 4dintnam.ads, 4mintnam.ads, 4uintnam.ads, 52system.ads,
	5dosinte.ads, 5etpopse.adb, 5mosinte.ads, 5qosinte.adb,
	5qosinte.ads, 5qstache.adb, 5qtaprop.adb, 5qtaspri.ads,
	5stpopse.adb, 5uintman.adb, 5uosinte.ads, adafinal.c,
	g-enblsp.adb, io-aux.c, scn-nlit.adb, scn-slit.adb,
	s-exnflt.ads, s-exngen.adb, s-exngen.ads, s-exnlfl.ads,
	s-exnlin.ads, s-exnsfl.ads, s-exnsin.ads, s-exnssi.ads,
	s-expflt.ads, s-expgen.adb, s-expgen.ads, s-explfl.ads,
	s-explin.ads, s-expllf.ads, s-expsfl.ads, s-expsin.ads,
	s-expssi.ads, style.adb: Files removed. Merge with ACT tree.

	* 1ic.ads, 31soccon.ads, 31soliop.ads, 3asoccon.ads,
	3bsoccon.ads, 3gsoccon.ads, 3hsoccon.ads, 3ssoccon.ads,
	3ssoliop.ads, 3wsoccon.ads, 3wsocthi.adb, 3wsocthi.ads,
	3wsoliop.ads, 41intnam.ads, 42intnam.ads, 4aintnam.ads,
	4cintnam.ads, 4gintnam.ads, 4hexcpol.adb, 4hintnam.ads,
	4lintnam.ads, 4nintnam.ads, 4ointnam.ads, 4onumaux.ads,
	4pintnam.ads, 4sintnam.ads, 4vcaldel.adb, 4vcalend.adb,
	4vintnam.ads, 4wexcpol.adb, 4wintnam.ads, 4zintnam.ads,
	51osinte.adb, 51osinte.ads, 52osinte.adb, 52osinte.ads,
	53osinte.ads, 54osinte.ads, 5aosinte.adb, 5aosinte.ads,
	5asystem.ads, 5ataprop.adb, 5atasinf.ads, 5ataspri.ads,
	5atpopsp.adb, 5avxwork.ads, 5bosinte.adb, 5bosinte.ads,
	5bsystem.ads, 5cosinte.ads, 5esystem.ads, 5fintman.adb,
	5fosinte.ads, 5fsystem.ads, 5ftaprop.adb, 5ftasinf.ads,
	5ginterr.adb, 5gintman.adb, 5gmastop.adb, 5gosinte.ads,
	5gproinf.ads, 5gsystem.ads, 5gtaprop.adb, 5gtasinf.ads,
	5gtpgetc.adb, 5hosinte.adb, 5hosinte.ads, 5hsystem.ads,
	5htaprop.adb, 5htaspri.ads, 5htraceb.adb, 5iosinte.adb,
	5itaprop.adb, 5itaspri.ads, 5ksystem.ads, 5kvxwork.ads,
	5lintman.adb, 5lml-tgt.adb, 5losinte.ads, 5lsystem.ads,
	5mvxwork.ads, 5ninmaop.adb, 5nintman.adb, 5nosinte.ads,
	5ntaprop.adb, 5ntaspri.ads, 5ointerr.adb, 5omastop.adb,
	5oosinte.adb, 5oosinte.ads, 5oosprim.adb, 5oparame.adb,
	5osystem.ads, 5otaprop.adb, 5otaspri.ads, 5posinte.ads,
	5posprim.adb, 5pvxwork.ads, 5sintman.adb, 5sosinte.adb,
	5sosinte.ads, 5ssystem.ads, 5staprop.adb, 5stasinf.ads,
	5staspri.ads, 5svxwork.ads, 5tosinte.ads, 5vasthan.adb,
	5vinmaop.adb, 5vinterr.adb, 5vintman.adb, 5vintman.ads,
	5vmastop.adb, 5vosinte.adb, 5vosinte.ads, 5vosprim.adb,
	5vsystem.ads, 5vtaprop.adb, 5vtaspri.ads, 5vtpopde.adb,
	5vtpopde.ads, 5wgloloc.adb, 5wintman.adb, 5wmemory.adb,
	5wosprim.adb, 5wsystem.ads, 5wtaprop.adb, 5wtaspri.ads,
	5ysystem.ads, 5zinterr.adb, 5zintman.adb, 5zosinte.adb,
	5zosinte.ads, 5zosprim.adb, 5zsystem.ads, 5ztaprop.adb,
	6vcpp.adb, 6vcstrea.adb, 6vinterf.ads, 7sinmaop.adb,
	7sintman.adb, 7sosinte.adb, 7sosprim.adb, 7staprop.adb,
	7staspri.ads, 7stpopsp.adb, 7straceb.adb, 9drpc.adb,
	a-caldel.adb, a-caldel.ads, a-charac.ads, a-colien.ads,
	a-comlin.adb, adaint.c, adaint.h, ada-tree.def,
	a-diocst.adb, a-diocst.ads, a-direio.adb, a-except.adb,
	a-except.ads, a-excpol.adb, a-exctra.adb, a-exctra.ads,
	a-filico.adb, a-interr.adb, a-intsig.adb, a-intsig.ads,
	ali.adb, ali.ads, ali-util.adb, ali-util.ads,
	a-ngcefu.adb, a-ngcoty.adb, a-ngelfu.adb, a-nudira.adb,
	a-nudira.ads, a-nuflra.adb, a-nuflra.ads, a-reatim.adb,
	a-reatim.ads, a-retide.ads, a-sequio.adb, a-siocst.adb,
	a-siocst.ads, a-ssicst.adb, a-ssicst.ads, a-strbou.adb,
	a-strbou.ads, a-strfix.adb, a-strmap.adb, a-strsea.ads,
	a-strunb.adb, a-strunb.ads, a-ststio.adb, a-stunau.adb,
	a-stunau.ads, a-stwibo.adb, a-stwibo.ads, a-stwifi.adb,
	a-stwima.adb, a-stwiun.adb, a-stwiun.ads, a-tags.adb,
	a-tags.ads, a-tasatt.adb, a-taside.adb, a-teioed.adb,
	a-textio.adb, a-textio.ads, a-tienau.adb, a-tifiio.adb,
	a-tiflau.adb, a-tiflio.adb, a-tigeau.adb, a-tigeau.ads,
	a-tiinau.adb, a-timoau.adb, a-tiocst.adb, a-tiocst.ads,
	atree.adb, atree.ads, a-witeio.adb, a-witeio.ads,
	a-wtcstr.adb, a-wtcstr.ads, a-wtdeio.adb, a-wtedit.adb,
	a-wtenau.adb, a-wtflau.adb, a-wtinau.adb, a-wtmoau.adb,
	bcheck.adb, binde.adb, bindgen.adb, bindusg.adb,
	checks.adb, checks.ads, cio.c, comperr.adb,
	comperr.ads, csets.adb, cstand.adb, cstreams.c,
	debug_a.adb, debug_a.ads, debug.adb, decl.c,
	einfo.adb, einfo.ads, errout.adb, errout.ads,
	eval_fat.adb, eval_fat.ads, exp_aggr.adb, expander.adb,
	expander.ads, exp_attr.adb, exp_ch11.adb, exp_ch13.adb,
	exp_ch2.adb, exp_ch3.adb, exp_ch3.ads, exp_ch4.adb,
	exp_ch5.adb, exp_ch6.adb, exp_ch7.adb, exp_ch7.ads,
	exp_ch8.adb, exp_ch9.adb, exp_code.adb, exp_dbug.adb,
	exp_dbug.ads, exp_disp.adb, exp_dist.adb, expect.c,
	exp_fixd.adb, exp_imgv.adb, exp_intr.adb, exp_pakd.adb,
	exp_prag.adb, exp_strm.adb, exp_strm.ads, exp_tss.adb,
	exp_tss.ads, exp_util.adb, exp_util.ads, exp_vfpt.adb,
	fe.h, fmap.adb, fmap.ads, fname.adb,
	fname.ads, fname-uf.adb, fname-uf.ads, freeze.adb,
	freeze.ads, frontend.adb, g-awk.adb, g-awk.ads,
	g-busora.adb, g-busora.ads, g-busorg.adb, g-busorg.ads,
	g-casuti.adb, g-casuti.ads, g-catiio.adb, g-catiio.ads,
	g-cgi.adb, g-cgi.ads, g-cgicoo.adb, g-cgicoo.ads,
	g-cgideb.adb, g-cgideb.ads, g-comlin.adb, g-comlin.ads,
	g-crc32.adb, g-crc32.ads, g-debpoo.adb, g-debpoo.ads,
	g-debuti.adb, g-debuti.ads, g-diopit.adb, g-diopit.ads,
	g-dirope.adb, g-dirope.ads, g-dyntab.adb, g-dyntab.ads,
	g-except.ads, g-exctra.adb, g-exctra.ads, g-expect.adb,
	g-expect.ads, g-hesora.adb, g-hesora.ads, g-hesorg.adb,
	g-hesorg.ads, g-htable.adb, g-htable.ads, gigi.h,
	g-io.adb, g-io.ads, g-io_aux.adb, g-io_aux.ads,
	g-locfil.adb, g-locfil.ads, g-md5.adb, g-md5.ads,
	gmem.c, gnat1drv.adb, gnatbind.adb, gnatchop.adb,
	gnatcmd.adb, gnatfind.adb, gnatkr.adb, gnatlbr.adb,
	gnatlink.adb, gnatls.adb, gnatmake.adb, gnatmem.adb,
	gnatname.adb, gnatprep.adb, gnatprep.ads, gnatpsta.adb,
	gnatxref.adb, g-os_lib.adb, g-os_lib.ads, g-regexp.adb,
	g-regexp.ads, g-regist.adb, g-regist.ads, g-regpat.adb,
	g-regpat.ads, g-soccon.ads, g-socket.adb, g-socket.ads,
	g-socthi.adb, g-socthi.ads, g-soliop.ads, g-souinf.ads,
	g-speche.adb, g-speche.ads, g-spipat.adb, g-spipat.ads,
	g-spitbo.adb, g-spitbo.ads, g-sptabo.ads, g-sptain.ads,
	g-sptavs.ads, g-table.adb, g-table.ads, g-tasloc.adb,
	g-tasloc.ads, g-thread.adb, g-thread.ads, g-traceb.adb,
	g-traceb.ads, g-trasym.adb, g-trasym.ads, hostparm.ads,
	i-c.ads, i-cobol.adb, i-cpp.adb, i-cstrea.ads,
	i-cstrin.adb, i-cstrin.ads, impunit.adb, init.c,
	inline.adb, interfac.ads, i-pacdec.ads, itypes.adb,
	itypes.ads, i-vxwork.ads, lang.opt, lang-specs.h,
	layout.adb, lib.adb, lib.ads, lib-list.adb,
	lib-load.adb, lib-load.ads, lib-sort.adb, lib-util.adb,
	lib-writ.adb, lib-writ.ads, lib-xref.adb, lib-xref.ads,
	link.c, live.adb, make.adb, make.ads,
	Makefile.adalib, Makefile.in, Make-lang.in, makeusg.adb,
	mdll.adb, mdll-fil.adb, mdll-fil.ads, mdll-utl.adb,
	mdll-utl.ads, memroot.adb, memroot.ads, memtrack.adb,
	misc.c, mkdir.c, mlib.adb, mlib.ads,
	mlib-fil.adb, mlib-fil.ads, mlib-prj.adb, mlib-prj.ads,
	mlib-tgt.adb, mlib-tgt.ads, mlib-utl.adb, mlib-utl.ads,
	namet.adb, namet.ads, namet.h, nlists.ads,
	nlists.h, nmake.adt, opt.adb, opt.ads,
	osint.adb, osint.ads, osint-b.adb, osint-c.adb,
	par.adb, par-ch10.adb, par-ch11.adb, par-ch2.adb,
	par-ch3.adb, par-ch4.adb, par-ch5.adb, par-ch6.adb,
	par-ch9.adb, par-endh.adb, par-labl.adb, par-load.adb,
	par-prag.adb, par-sync.adb, par-tchk.adb, par-util.adb,
	prj.adb, prj.ads, prj-attr.adb, prj-attr.ads,
	prj-com.adb, prj-com.ads, prj-dect.adb, prj-dect.ads,
	prj-env.adb, prj-env.ads, prj-ext.adb, prj-ext.ads,
	prj-makr.adb, prj-makr.ads, prj-nmsc.adb, prj-nmsc.ads,
	prj-pars.adb, prj-pars.ads, prj-part.adb, prj-part.ads,
	prj-pp.adb, prj-pp.ads, prj-proc.adb, prj-proc.ads,
	prj-strt.adb, prj-strt.ads, prj-tree.adb, prj-tree.ads,
	prj-util.adb, prj-util.ads, raise.c, raise.h,
	repinfo.adb, repinfo.h, restrict.adb, restrict.ads,
	rident.ads, rtsfind.adb, rtsfind.ads, s-addima.ads,
	s-arit64.adb, s-assert.adb, s-assert.ads, s-atacco.adb,
	s-atacco.ads, s-auxdec.adb, s-auxdec.ads, s-bitops.adb,
	scans.ads, scn.adb, scn.ads, s-crc32.adb,
	s-crc32.ads, s-direio.adb, sem.adb, sem.ads,
	sem_aggr.adb, sem_attr.adb, sem_attr.ads, sem_case.adb,
	sem_case.ads, sem_cat.adb, sem_cat.ads, sem_ch10.adb,
	sem_ch11.adb, sem_ch12.adb, sem_ch12.ads, sem_ch13.adb,
	sem_ch13.ads, sem_ch3.adb, sem_ch3.ads, sem_ch4.adb,
	sem_ch5.adb, sem_ch5.ads, sem_ch6.adb, sem_ch6.ads,
	sem_ch7.adb, sem_ch7.ads, sem_ch8.adb, sem_ch8.ads,
	sem_ch9.adb, sem_disp.adb, sem_disp.ads, sem_dist.adb,
	sem_elab.adb, sem_eval.adb, sem_eval.ads, sem_intr.adb,
	sem_maps.adb, sem_mech.adb, sem_prag.adb, sem_prag.ads,
	sem_res.adb, sem_res.ads, sem_type.adb, sem_type.ads,
	sem_util.adb, sem_util.ads, sem_warn.adb, s-errrep.adb,
	s-errrep.ads, s-exctab.adb, s-exctab.ads, s-exnint.ads,
	s-exnllf.ads, s-exnlli.ads, s-expint.ads, s-explli.ads,
	s-expuns.ads, s-fatflt.ads, s-fatgen.adb, s-fatgen.ads,
	s-fatlfl.ads, s-fatllf.ads, s-fatsfl.ads, s-fileio.adb,
	s-fileio.ads, s-finimp.adb, s-finimp.ads, s-finroo.adb,
	s-finroo.ads, sfn_scan.adb, s-gloloc.adb, s-gloloc.ads,
	s-imgdec.adb, s-imgenu.adb, s-imgrea.adb, s-imgwch.adb,
	sinfo.adb, sinfo.ads, s-inmaop.ads, sinput.adb,
	sinput.ads, sinput-d.adb, sinput-l.adb, sinput-l.ads,
	sinput-p.adb, sinput-p.ads, s-interr.adb, s-interr.ads,
	s-intman.ads, s-maccod.ads, s-mastop.adb, s-mastop.ads,
	s-memory.adb, s-memory.ads, snames.adb, snames.ads,
	snames.h, s-osprim.ads, s-parame.ads, s-parint.ads,
	s-pooloc.adb, s-pooloc.ads, s-poosiz.adb, sprint.adb,
	s-proinf.ads, s-scaval.ads, s-secsta.adb, s-secsta.ads,
	s-sequio.adb, s-shasto.adb, s-shasto.ads, s-soflin.ads,
	s-stache.adb, s-stache.ads, s-stalib.adb, s-stalib.ads,
	s-stoele.ads, s-stopoo.ads, s-stratt.adb, s-stratt.ads,
	s-strops.adb, s-strops.ads, s-taasde.adb, s-taasde.ads,
	s-tadeca.adb, s-tadeca.ads, s-tadert.adb, s-tadert.ads,
	s-taenca.adb, s-taenca.ads, s-taprob.adb, s-taprob.ads,
	s-taprop.ads, s-tarest.adb, s-tarest.ads, s-tasdeb.adb,
	s-tasdeb.ads, s-tasinf.adb, s-tasinf.ads, s-tasini.adb,
	s-tasini.ads, s-taskin.adb, s-taskin.ads, s-tasque.adb,
	s-tasque.ads, s-tasren.adb, s-tasren.ads, s-tasres.ads,
	s-tassta.adb, s-tassta.ads, s-tasuti.adb, s-tasuti.ads,
	s-tataat.adb, s-tataat.ads, s-tpinop.adb, s-tpinop.ads,
	s-tpoben.adb, s-tpoben.ads, s-tpobop.adb, s-tpobop.ads,
	s-tposen.adb, s-tposen.ads, s-traceb.adb, s-traceb.ads,
	stringt.adb, stringt.ads, stringt.h, style.ads,
	stylesw.adb, stylesw.ads, s-unstyp.ads, s-vaflop.ads,
	s-valrea.adb, s-valuti.adb, s-vercon.adb, s-vmexta.adb,
	s-wchcnv.ads, s-wchcon.ads, s-widcha.adb, switch.adb,
	switch.ads, switch-b.adb, switch-c.adb, switch-m.adb,
	s-wwdcha.adb, s-wwdwch.adb, sysdep.c, system.ads,
	table.adb, table.ads, targparm.adb, targparm.ads,
	targtyps.c, tbuild.adb, tbuild.ads, tracebak.c,
	trans.c, tree_io.adb, treepr.adb, treeprs.adt,
	ttypes.ads, types.ads, types.h, uintp.adb,
	uintp.ads, uintp.h, uname.adb, urealp.adb,
	urealp.ads, urealp.h, usage.adb, utils2.c,
	utils.c, validsw.adb, validsw.ads, widechar.adb,
	xeinfo.adb, xnmake.adb, xref_lib.adb, xref_lib.ads,
	xr_tabls.adb, xr_tabls.ads, xtreeprs.adb, xsnames.adb,
	einfo.h, sinfo.h, treeprs.ads, nmake.ads, nmake.adb,
	gnatvsn.ads: Merge with ACT tree.

	* gnatvsn.adb: Rewritten in a simpler and more efficient way.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@72751 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 218 insertions, 1007 deletions

diff --git a/gcc/ada/tracebak.c b/gcc/ada/tracebak.c
index e89a7b42f28..0df46e2fad9 100644
--- a/gcc/ada/tracebak.c
+++ b/gcc/ada/tracebak.c
@@ -6,8 +6,7 @@
  *                                                                          *
  *                          C Implementation File                           *
  *                                                                          *
- *                                                                          *
- *           Copyright (C) 2000-2001 Ada Core Technologies, Inc.            *
+ *           Copyright (C) 2000-2003 Ada Core Technologies, Inc.            *
  *                                                                          *
  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  * terms of the  GNU General Public License as published  by the Free Soft- *
@@ -27,14 +26,13 @@
  * file might be covered by the  GNU Public License.                        *
  *                                                                          *
  * GNAT was originally developed  by the GNAT team at  New York University. *
- * It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). *
+ * Extensive contributions were provided by Ada Core Technologies Inc.      *
  *                                                                          *
  ****************************************************************************/
 
 /* This file contains low level support for stack unwinding using GCC intrinsic
    functions.
    It has been tested on the following configurations:
-   HPPA/HP-UX
    PowerPC/AiX
    PowerPC/VxWorks
    Sparc/Solaris
@@ -44,6 +42,7 @@
    i386/OS2
    i386/LynxOS
    Alpha/VxWorks
+   Alpha/VMS
 */
 
 #ifdef __alpha_vxworks
@@ -59,42 +58,140 @@
 #include "system.h"
 #endif
 
+extern int __gnat_backtrace PARAMS ((void **, int, void *, void *, int));
+
+/* The point is to provide an implementation of the __gnat_bactrace function
+   above, called by the default implementation of the System.Traceback
+   package.
+
+   We first have a series of target specific implementations, each included
+   from a separate C file for readability purposes.
+
+   Then comes a somewhat generic implementation based on a set of macro and
+   structure definitions which may be tailored on a per target basis. The
+   presence of a definition for one of these macros (PC_ADJUST) controls
+   wether or not the generic implementation is included.
+
+   Finally, there is a default dummy implementation, necessary to make the
+   linker happy on platforms where the feature is not supported, but where the
+   function is still referenced by the default System.Traceback.  */
+
 #define Lock_Task system__soft_links__lock_task
 extern void (*Lock_Task) PARAMS ((void));
 
 #define Unlock_Task system__soft_links__unlock_task
 extern void (*Unlock_Task) PARAMS ((void));
 
-#ifndef CURRENT_STACK_FRAME
-# define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
-#endif
-
-extern int __gnat_backtrace	PARAMS ((void **, int, void *, void *));
-
-#if defined (__hppa)
-struct layout
-{
-  void *return_address;
-  void *pad[4];
-  struct layout *next;
-};
+/*-------------------------------------*
+ *-- Target specific implementations --*
+ *-------------------------------------*/
 
-#define FRAME_LEVEL 1
-#define FRAME_OFFSET -20
-#define SKIP_FRAME 1
-#define PC_ADJUST -4
+#if defined (__alpha_vxworks)
 
-/* If CURRENT is unaligned, it means that CURRENT is not a valid frame
-   pointer and we should stop popping frames. */
+#include "tb-alvxw.c"
 
-#define STOP_FRAME(CURRENT, TOP_STACK) \
-  (((int) (CURRENT) & 0x3) != 0 && (CURRENT)->return_address == 0)
+#elif defined (__ALPHA) && defined (__VMS__)
 
-/* Current implementation need to be protected against invalid memory
-   accesses */
-#define PROTECT_SEGV
+#include "tb-alvms.c"
 
-#elif defined (_AIX)
+#else
+/* No target specific implementation.  */
+
+/*----------------------------------------------------------------*
+ *-- Target specific definitions for the generic implementation --*
+ *----------------------------------------------------------------*/
+
+/* The stack layout is specified by the target ABI. The "generic" scheme is
+   based on the following assumption:
+
+     The stack layout from some frame pointer is such that the information
+     required to compute the backtrace is available at static offsets.
+
+   For a given frame, the information we are interested in is the saved return
+   address (somewhere after the call instruction in the caller) and a pointer
+   to the caller's frame. The former is the base of the call chain information
+   we store in the tracebacks array. The latter allows us to loop over the
+   successive frames in the chain.
+
+   To initiate the process, we retrieve an initial frame pointer using the
+   appropriate GCC builtin (__builtin_frame_address).
+
+   This scheme is unfortunately not applicable on every target because the
+   stack layout is not necessarily regular (static) enough. On targets where
+   this scheme applies, the implementation relies on the following items:
+
+   o struct layout, describing the expected stack data layout relevant to the
+     information we are interested in,
+
+   o FRAME_OFFSET, the offset, from a given frame pointer, at which this
+     layout will be found,
+
+   o FRAME_LEVEL, controls how many frames up we get at to start with,
+     from the initial frame pointer we compute by way of the GCC builtin,
+
+     0 is most often the appropriate value. 1 may be necessary on targets
+     where return addresses are saved by a function in it's caller's frame
+     (e.g. PPC).
+
+   o PC_ADJUST, to account for the difference between a call point (address
+     of a call instruction), which is what we want in the output array, and
+     the associated return address, which is what we retrieve from the stack.
+
+   o STOP_FRAME, to decide wether we reached the top of the call chain, and
+     thus if the process shall stop.
+
+	   :
+	   :                   stack
+	   |             +----------------+
+	   |   +-------->|       :        |
+	   |   |         | (FRAME_OFFSET) |
+	   |   |         |       :        |  (PC_ADJUST)
+	   |   |  layout:| return_address ----------------+
+	   |   |         |     ....       |               |
+	   +---------------  next_frame   |               |
+	       |         |     ....       |               |
+	       |         |                |               |
+	       |         +----------------+               |  +-----+
+	       |         |       :        |<- Base fp     |  |  :  |
+	       |         | (FRAME_OFFSET) | (FRAME_LEVEL) |  |  :  |
+	       |         |       :        |               +--->    | [1]
+	       |  layout:| return_address -------------------->    | [0]
+	       |         |       ...      |  (PC_ADJUST)     +-----+
+	       +----------   next_frame   |                 traceback[]
+		         |       ...      |
+		         |                |
+		         +----------------+
+
+   o BASE_SKIP,
+
+   Since we inherently deal with return addresses, there is an implicit shift
+   by at least one for the initial point we are able to observe in the chain.
+
+   On some targets (e.g. sparc-solaris), the first return address we can
+   easily get without special code is even our caller's return address, so
+   there is a initial shift of two.
+
+   BASE_SKIP represents this initial shift, which is the minimal "skip_frames"
+   value we support. We could add special code for the skip_frames < BASE_SKIP
+   cases. This is not done currently because there is virtually no situation
+   in which this would be useful.
+
+   Finally, to account for some ABI specificities, a target may (but does
+   not have to) define:
+
+   o FORCE_CALL, to force a call to a dummy function at the very beginning
+     of the computation. See the PPC AIX target for an example where this
+     is useful.
+
+   o FETCH_UP_FRAME, to force an invocation of __builtin_frame_address with a
+     positive argument right after a possibly forced call even if FRAME_LEVEL
+     is 0. See the Sparc Solaris case for an example where this is useful.
+
+  */
+
+/*------------------------------ PPC AIX -------------------------------*/
+
+#if defined (_AIX)
 struct layout
 {
   struct layout *next;
@@ -102,12 +199,24 @@ struct layout
   void *return_address;
 };
 
-#define FRAME_LEVEL 1
 #define FRAME_OFFSET 0
-#define SKIP_FRAME 2
 #define PC_ADJUST -4
 #define STOP_FRAME(CURRENT, TOP_STACK) ((void *) (CURRENT) < (TOP_STACK))
 
+/* The PPC ABI has an interesting specificity: the return address saved by a
+   function is located in it's caller's frame, and the save operation only
+   takes place if the function performs a call.
+
+   To have __gnat_backtrace retrieve it's own return address, we then
+   define ... */
+
+#define FORCE_CALL
+#define FRAME_LEVEL 1
+
+#define BASE_SKIP 1
+
+/*---------------------------- PPC VxWorks------------------------------*/
+
 #elif defined (_ARCH_PPC) && defined (__vxworks)
 struct layout
 {
@@ -115,27 +224,48 @@ struct layout
   void *return_address;
 };
 
+#define FORCE_CALL
 #define FRAME_LEVEL 1
+/* See the PPC AIX case for an explanation of these values.  */
+
 #define FRAME_OFFSET 0
-#define SKIP_FRAME 2
-#define PC_ADJUST 0
+#define PC_ADJUST -4
 #define STOP_FRAME(CURRENT, TOP_STACK) ((CURRENT)->return_address == 0)
 
+#define BASE_SKIP 1
+
+/*-------------------------- Sparc Solaris -----------------------------*/
+
 #elif defined (sun) && defined (sparc)
+
+/* These definitions are inspired from the Appendix D (Software
+   Considerations) of the SPARC V8 architecture manual.  */
+
 struct layout
 {
   struct layout *next;
   void *return_address;
 };
 
-#define FRAME_LEVEL 1
-#define FRAME_OFFSET (14*4)
-#define SKIP_FRAME 1
+#define FRAME_LEVEL 0
+#define FRAME_OFFSET (14 * (sizeof (void*)))
 #define PC_ADJUST 0
 #define STOP_FRAME(CURRENT, TOP_STACK) \
   ((CURRENT)->return_address == 0|| (CURRENT)->next == 0 \
    || (void *) (CURRENT) < (TOP_STACK))
 
+/* The sparc register windows need to be flushed before we may access them
+   from the stack. This is achieved by way of builtin_frame_address only
+   when the "count" argument is positive, so force at least one such call.  */
+#define FETCH_UP_FRAME_ADDRESS
+
+#define BASE_SKIP 2
+/* From the frame pointer of frame N, we are accessing the flushed register
+   window of frame N-1 (positive offset from fp), in which we retrieve the
+   saved return address. We then end up with our caller's return address.  */
+
+/*------------------------------- x86 ----------------------------------*/
+
 #elif defined (i386)
 struct layout
 {
@@ -154,13 +284,14 @@ extern unsigned int _image_base__;
 
 #define FRAME_LEVEL 0
 #define FRAME_OFFSET 0
-#define SKIP_FRAME 1
 #define PC_ADJUST -2
 #define STOP_FRAME(CURRENT, TOP_STACK) \
   ((unsigned int)(CURRENT)->return_address < LOWEST_ADDR \
    || (CURRENT)->return_address == 0|| (CURRENT)->next == 0  \
    || (void *) (CURRENT) < (TOP_STACK))
 
+#define BASE_SKIP 1
+
 /* On i386 architecture we check that at the call point we really have a call
    insn. Possible call instructions are:
 
@@ -175,91 +306,75 @@ extern unsigned int _image_base__;
 
 #define VALID_STACK_FRAME(ptr) \
    (((*((ptr) - 3) & 0xff) == 0xe8) \
-    || ((*((ptr) - 4) & 0xff) == 0x9a) \
-    || ((*((ptr) - 2) & 0xff) == 0xff) \
-    || (((*((ptr) - 1) & 0xff00) == 0xff00) \
-        && ((*((ptr) - 1) & 0xf0) == 0xd0)))
+    || ((*((ptr) - 5) & 0xff) == 0x9a) \
+    || ((*((ptr) - 1) & 0xff) == 0xff) \
+    || (((*(ptr) & 0xd0ff) == 0xd0ff)))
 
-#elif defined (__alpha_vxworks)
-
-#define SKIP_FRAME 1
-#define PC_ADJUST -4
-
-extern void kerTaskEntry();
-
-#define STOP_FRAME \
-   (current == NULL \
-    || ((CORE_ADDR) &kerTaskEntry >= PROC_LOW_ADDR (current->proc_desc) \
-        && current->pc >= (CORE_ADDR) &kerTaskEntry))
 #endif
 
-#if !defined (PC_ADJUST)
-int
-__gnat_backtrace (array, size, exclude_min, exclude_max)
-     void **array ATTRIBUTE_UNUSED;
-     int size ATTRIBUTE_UNUSED;
-     void *exclude_min ATTRIBUTE_UNUSED;
-     void *exclude_max ATTRIBUTE_UNUSED;
-{
-  return 0;
-}
-
-#elif !defined (__alpha_vxworks)
-
-#ifdef PROTECT_SEGV
-#include <setjmp.h>
-#include <signal.h>
+/*---------------------------------------*
+ *-- The generic implementation per se --*
+ *---------------------------------------*/
 
-static jmp_buf sigsegv_excp;
+#if defined (PC_ADJUST)
 
-static void
-segv_handler (ignored)
-     int ignored;
-{
-  longjmp (sigsegv_excp, 1);
-}
+#ifndef CURRENT_STACK_FRAME
+# define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
 #endif
 
+
 #ifndef VALID_STACK_FRAME
 #define VALID_STACK_FRAME(ptr) 1
 #endif
 
+#define MAX(x,y) ((x) > (y) ? (x) : (y))
+
+/* Define a dummy function to call if FORCE_CALL is defined.  Don't
+   define it otherwise, as this could lead to "defined but not used"
+   warnings.  */
+#if defined (FORCE_CALL)
+static void forced_callee () {}
+#endif
+
 int
-__gnat_backtrace (array, size, exclude_min, exclude_max)
+__gnat_backtrace (array, size, exclude_min, exclude_max, skip_frames)
      void **array;
      int size;
      void *exclude_min;
      void *exclude_max;
+     int skip_frames;
 {
   struct layout *current;
   void *top_frame;
   void *top_stack;
   int cnt = 0;
 
-#ifdef PROTECT_SEGV
-  struct sigaction this_act, old_act;
+  /* Honor FORCE_CALL when defined.  */
+#if defined (FORCE_CALL)
+  forced_callee ();
+#endif
 
-  /* This function is not thread safe if PROTECT_SEGV is defined, so
-     protect it */
-  (*Lock_Task) ();
+  /* Force a call to builtin_frame_address with a positive argument
+     if required. This is necessary e.g. on sparc to have the register
+     windows flushed before we attempt to access them on the stack.  */
+#if defined (FETCH_UP_FRAME_ADDRESS) && (FRAME_LEVEL == 0)
+  __builtin_frame_address (1);
 #endif
 
   top_frame = __builtin_frame_address (FRAME_LEVEL);
   top_stack = CURRENT_STACK_FRAME;
   current = (struct layout *) ((size_t) top_frame + FRAME_OFFSET);
 
-#ifdef PROTECT_SEGV
-  this_act.sa_handler = segv_handler;
-  sigemptyset (&this_act.sa_mask);
-  this_act.sa_flags = 0;
-  sigaction (SIGSEGV, &this_act, &old_act);
+  /* Skip the number of calls we have been requested to skip, accounting for
+     the BASE_SKIP parameter.
 
-  if (setjmp (sigsegv_excp))
-    goto Done;
-#endif
+     FRAME_LEVEL is meaningless for the count adjustment. It impacts where we
+     start retrieving data from, but how many frames "up" we start at is in
+     BASE_SKIP by definition.  */
 
-  /* We skip the call to this function, it makes no sense to record it.  */
-  while (cnt < SKIP_FRAME)
+  skip_frames = MAX (0, skip_frames - BASE_SKIP);
+
+  while (cnt < skip_frames)
     {
       current = (struct layout *) ((size_t) current->next + FRAME_OFFSET);
       cnt++;
@@ -268,7 +383,7 @@ __gnat_backtrace (array, size, exclude_min, exclude_max)
   cnt = 0;
   while (cnt < size)
     {
-      if (STOP_FRAME (current, top_stack) || 
+      if (STOP_FRAME (current, top_stack) ||
 	  !VALID_STACK_FRAME((char *)(current->return_address + PC_ADJUST)))
         break;
 
@@ -279,931 +394,27 @@ __gnat_backtrace (array, size, exclude_min, exclude_max)
       current = (struct layout *) ((size_t) current->next + FRAME_OFFSET);
     }
 
-#ifdef PROTECT_SEGV
- Done:
-  sigaction (SIGSEGV, &old_act, NULL);
-  (*Unlock_Task) ();
-#endif
   return cnt;
 }
 
 #else
-/* Alpha vxWorks requires a special, complex treatment that is extracted
-   from GDB */
-
-#include <string.h>
-
-/* Register numbers of various important registers.
-   Note that most of these values are "real" register numbers,
-   and correspond to the general registers of the machine,
-   and FP_REGNUM is a "phony" register number which is too large
-   to be an actual register number as far as the user is concerned
-   but serves to get the desired value when passed to read_register.  */
-
-#define T7_REGNUM 8		/* Return address register for OSF/1 __add* */
-#define GCC_FP_REGNUM 15	/* Used by gcc as frame register */
-#define T9_REGNUM 23		/* Return address register for OSF/1 __div* */
-#define SP_REGNUM 30		/* Contains address of top of stack */
-#define RA_REGNUM 26		/* Contains return address value */
-#define FP0_REGNUM 32		/* Floating point register 0 */
-#define PC_REGNUM 64		/* Contains program counter */
-#define NUM_REGS 66
-
-#define VM_MIN_ADDRESS (CORE_ADDR)0x120000000
-
-#define SIZEOF_FRAME_SAVED_REGS (sizeof (CORE_ADDR) * (NUM_REGS))
-#define INIT_EXTRA_FRAME_INFO(fromleaf, fci) init_extra_frame_info(fci)
-
-#define FRAME_CHAIN(thisframe) (CORE_ADDR) alpha_frame_chain (thisframe)
-
-#define FRAME_CHAIN_VALID(CHAIN, THISFRAME)	\
-  ((CHAIN) != 0					\
-   && !inside_entry_file (FRAME_SAVED_PC (THISFRAME)))
-
-#define FRAME_SAVED_PC(FRAME)	(alpha_frame_saved_pc (FRAME))
-
-#define	FRAME_CHAIN_COMBINE(CHAIN, THISFRAME) (CHAIN)
-
-#define	INIT_FRAME_PC(FROMLEAF, PREV)
-
-#define INIT_FRAME_PC_FIRST(FROMLEAF, PREV) \
-  (PREV)->pc = ((FROMLEAF) ? SAVED_PC_AFTER_CALL ((PREV)->next) \
-		: (PREV)->next ? FRAME_SAVED_PC ((prev)->NEXT) : read_pc ());
-
-#define SAVED_PC_AFTER_CALL(FRAME)	alpha_saved_pc_after_call (FRAME)
-
-typedef unsigned long long int bfd_vma;
-
-typedef bfd_vma CORE_ADDR;
-
-typedef struct pdr
-{
-  bfd_vma adr;		/* memory address of start of procedure */
-  long	isym;		/* start of local symbol entries */
-  long	iline;		/* start of line number entries*/
-  long	regmask;	/* save register mask */
-  long	regoffset;	/* save register offset */
-  long	iopt;		/* start of optimization symbol entries*/
-  long	fregmask;	/* save floating point register mask */
-  long	fregoffset;	/* save floating point register offset */
-  long	frameoffset;	/* frame size */
-  short	framereg;	/* frame pointer register */
-  short	pcreg;		/* offset or reg of return pc */
-  long	lnLow;		/* lowest line in the procedure */
-  long	lnHigh;		/* highest line in the procedure */
-  bfd_vma cbLineOffset;	/* byte offset for this procedure from the fd base */
-  /* These fields are new for 64 bit ECOFF.  */
-  unsigned gp_prologue : 8; /* byte size of GP prologue */
-  unsigned gp_used : 1;	/* true if the procedure uses GP */
-  unsigned reg_frame : 1; /* true if register frame procedure */
-  unsigned prof : 1;	/* true if compiled with -pg */
-  unsigned reserved : 13; /* reserved: must be zero */
-  unsigned localoff : 8; /* offset of local variables from vfp */
-} PDR;
-
-typedef struct alpha_extra_func_info
-{
-  long numargs;		/* number of args to procedure (was iopt) */
-  PDR pdr;			/* Procedure descriptor record */
-}
-*alpha_extra_func_info_t;
-
-struct frame_info
-{
-  /* Nominal address of the frame described.  See comments at FRAME_FP
-     about what this means outside the *FRAME* macros; in the *FRAME*
-     macros, it can mean whatever makes most sense for this machine.  */
-  CORE_ADDR frame;
-
-  /* Address at which execution is occurring in this frame.  For the
-     innermost frame, it's the current pc.  For other frames, it is a
-     pc saved in the next frame.  */
-  CORE_ADDR pc;
-
-  /* For each register, address of where it was saved on entry to the
-     frame, or zero if it was not saved on entry to this frame.  This
-     includes special registers such as pc and fp saved in special
-     ways in the stack frame.  The SP_REGNUM is even more special, the
-     address here is the sp for the next frame, not the address where
-     the sp was saved.  Allocated by frame_saved_regs_zalloc () which
-     is called and initialized by FRAME_INIT_SAVED_REGS. */
-  CORE_ADDR *saved_regs;	/*NUM_REGS */
-
-  int localoff;
-  int pc_reg;
-  alpha_extra_func_info_t proc_desc;
-
-  /* Pointers to the next and previous frame_info's in the frame cache.  */
-  struct frame_info *next, *prev;
-};
-
-struct frame_saved_regs
-{
-  /* For each register R (except the SP), regs[R] is the address at
-     which it was saved on entry to the frame, or zero if it was not
-     saved on entry to this frame.  This includes special registers
-     such as pc and fp saved in special ways in the stack frame.
-
-     regs[SP_REGNUM] is different.  It holds the actual SP, not the
-     address at which it was saved.  */
-
-  CORE_ADDR regs[NUM_REGS];
-};
-
-static CORE_ADDR theRegisters[32];
-
-/* Prototypes for local functions. */
-
-static CORE_ADDR read_next_frame_reg PARAMS ((struct frame_info *, int));
-static CORE_ADDR heuristic_proc_start PARAMS ((CORE_ADDR));
-static int alpha_about_to_return PARAMS ((CORE_ADDR pc));
-static void init_extra_frame_info PARAMS ((struct frame_info *));
-static CORE_ADDR alpha_frame_chain PARAMS ((struct frame_info *));
-static CORE_ADDR alpha_frame_saved_pc PARAMS ((struct frame_info *frame))
-static void *trace_alloc PARAMS ((unsigned int));
-static struct frame_info *create_new_frame PARAMS ((CORE_ADDR, CORE_ADDR));
-
-static alpha_extra_func_info_t
-heuristic_proc_desc PARAMS ((CORE_ADDR, CORE_ADDR, struct frame_info *,
-			     struct frame_saved_regs *));
-
-static alpha_extra_func_info_t
-find_proc_desc PARAMS ((CORE_ADDR, struct frame_info *,
-			struct frame_saved_regs *));
-
-/* Heuristic_proc_start may hunt through the text section for a long
-   time across a 2400 baud serial line.  Allows the user to limit this
-   search.  */
-static unsigned int heuristic_fence_post = 1<<16;
-
-/* Layout of a stack frame on the alpha:
-
-                |				|
- pdr members:	|  7th ... nth arg,		|
-                |  `pushed' by caller.		|
-                |				|
-----------------|-------------------------------|<--  old_sp == vfp
-   ^  ^  ^  ^	|				|
-   |  |  |  |	|				|
-   |  |localoff	|  Copies of 1st .. 6th		|
-   |  |  |  |	|  argument if necessary.	|
-   |  |  |  v	|				|
-   |  |  |  ---	|-------------------------------|<-- FRAME_LOCALS_ADDRESS
-   |  |  |      |				|
-   |  |  |      |  Locals and temporaries.	|
-   |  |  |      |				|
-   |  |  |      |-------------------------------|
-   |  |  |      |				|
-   |-fregoffset	|  Saved float registers.	|
-   |  |  |      |  F9				|
-   |  |  |      |   .				|
-   |  |  |      |   .				|
-   |  |  |      |  F2				|
-   |  |  v      |				|
-   |  |  -------|-------------------------------|
-   |  |         |				|
-   |  |         |  Saved registers.		|
-   |  |         |  S6				|
-   |-regoffset	|   .				|
-   |  |         |   .				|
-   |  |         |  S0				|
-   |  |         |  pdr.pcreg			|
-   |  v         |				|
-   |  ----------|-------------------------------|
-   |            |				|
- frameoffset    |  Argument build area, gets	|
-   |            |  7th ... nth arg for any	|
-   |            |  called procedure.		|
-   v            |  				|
-   -------------|-------------------------------|<-- sp
-                |				|            */
-
-#define PROC_LOW_ADDR(PROC) ((PROC)->pdr.adr)		    /* least address */
-#define PROC_HIGH_ADDR(PROC) ((PROC)->pdr.iline)      /* upper address bound */
-#define PROC_DUMMY_FRAME(PROC) ((PROC)->pdr.cbLineOffset) /*CALL_DUMMY frame */
-#define PROC_FRAME_OFFSET(PROC) ((PROC)->pdr.frameoffset)
-#define PROC_FRAME_REG(PROC) ((PROC)->pdr.framereg)
-#define PROC_REG_MASK(PROC) ((PROC)->pdr.regmask)
-#define PROC_FREG_MASK(PROC) ((PROC)->pdr.fregmask)
-#define PROC_REG_OFFSET(PROC) ((PROC)->pdr.regoffset)
-#define PROC_FREG_OFFSET(PROC) ((PROC)->pdr.fregoffset)
-#define PROC_PC_REG(PROC) ((PROC)->pdr.pcreg)
-#define PROC_LOCALOFF(PROC) ((PROC)->pdr.localoff)
-
-/* Local storage allocation/deallocation functions.  trace_alloc does
-   a malloc, but also chains allocated blocks on trace_alloc_chain, so
-   they may all be freed on exit from __gnat_backtrace. */
-
-struct alloc_chain
-{
-  struct alloc_chain *next;
-  double x[0];
-};
-struct alloc_chain *trace_alloc_chain;
-
-static void * 
-trace_alloc (n)
-     unsigned int n;
-{
-  struct alloc_chain * result = malloc (n + sizeof(struct alloc_chain));
-
-  result->next = trace_alloc_chain;
-  trace_alloc_chain = result;
-  return (void*) result->x;
-}
-
-static void
-free_trace_alloc ()
-{
-  while (trace_alloc_chain != 0)
-    {
-      struct alloc_chain *old = trace_alloc_chain;
-
-      trace_alloc_chain = trace_alloc_chain->next;
-      free (old);
-    }
-}
-
-/* Read value at ADDR into *DEST, returning 0 if this is valid, != 0
-   otherwise. */
-
-static int
-read_memory_safe4 (addr, dest)
-     CORE_ADDR addr;
-     unsigned int *dest;
-{
-  *dest = *((unsigned int*) addr);
-  return 0;
-}
+/* No target specific implementation and PC_ADJUST not defined.  */
 
-/* Read value at ADDR into *DEST, returning 0 if this is valid, != 0
-   otherwise. */
+/*------------------------------*
+ *-- The dummy implementation --*
+ *------------------------------*/
 
-static int
-read_memory_safe8 (addr, dest)
-     CORE_ADDR addr;
-     CORE_ADDR *dest;
+int
+__gnat_backtrace (array, size, exclude_min, exclude_max, skip_frames)
+     void **array ATTRIBUTE_UNUSED;
+     int size ATTRIBUTE_UNUSED;
+     void *exclude_min ATTRIBUTE_UNUSED;
+     void *exclude_max ATTRIBUTE_UNUSED;
+     int skip_frames ATTRIBUTE_UNUSED;
 {
-  *dest = *((CORE_ADDR*) addr);
   return 0;
 }
 
-static CORE_ADDR
-read_register (regno)
-     int regno;
-{
-  if (regno >= 0 && regno < 31)
-    return theRegisters[regno];
-
-  return (CORE_ADDR) 0;
-}
-
-static void
-frame_saved_regs_zalloc (fi)
-     struct frame_info *fi;
-{
-  fi->saved_regs = (CORE_ADDR *) trace_alloc (SIZEOF_FRAME_SAVED_REGS);
-  memset (fi->saved_regs, 0, SIZEOF_FRAME_SAVED_REGS);
-}
-
-static void *
-frame_obstack_alloc (size)
-     unsigned long size;
-{
-  return (void *) trace_alloc (size);
-}
-
-static int
-inside_entry_file (addr)
-     CORE_ADDR addr;
-{
-  if (addr == 0)
-    return 1;
-  else
-    return 0;
-}
-
-static CORE_ADDR
-alpha_saved_pc_after_call (frame)
-     struct frame_info *frame;
-{
-  CORE_ADDR pc = frame->pc;
-  alpha_extra_func_info_t proc_desc;
-  int pcreg;
-
-  proc_desc = find_proc_desc (pc, frame->next, NULL);
-  pcreg = proc_desc ? PROC_PC_REG (proc_desc) : RA_REGNUM;
-
-  return read_register (pcreg);
-}
-
-/* Guaranteed to set frame->saved_regs to some values (it never leaves it
-   NULL).  */
-
-static void
-alpha_find_saved_regs (frame)
-     struct frame_info *frame;
-{
-  int ireg;
-  CORE_ADDR reg_position;
-  unsigned long mask;
-  alpha_extra_func_info_t proc_desc;
-  int returnreg;
-
-  frame_saved_regs_zalloc (frame);
-
-  /* If it is the frame for __sigtramp, the saved registers are located in a
-     sigcontext structure somewhere on the stack. __sigtramp passes a pointer
-     to the sigcontext structure on the stack.  If the stack layout for
-     __sigtramp changes, or if sigcontext offsets change, we might have to
-     update this code.  */
-
-#ifndef SIGFRAME_PC_OFF
-#define SIGFRAME_PC_OFF		(2 * 8)
-#define SIGFRAME_REGSAVE_OFF	(4 * 8)
-#define SIGFRAME_FPREGSAVE_OFF	(SIGFRAME_REGSAVE_OFF + 32 * 8 + 8)
-#endif
-
-  proc_desc = frame->proc_desc;
-  if (proc_desc == NULL)
-    /* I'm not sure how/whether this can happen.  Normally when we can't
-       find a proc_desc, we "synthesize" one using heuristic_proc_desc
-       and set the saved_regs right away.  */
-    return;
-
-  /* Fill in the offsets for the registers which gen_mask says
-     were saved.  */
-
-  reg_position = frame->frame + PROC_REG_OFFSET (proc_desc);
-  mask = PROC_REG_MASK (proc_desc);
-
-  returnreg = PROC_PC_REG (proc_desc);
-
-  /* Note that RA is always saved first, regardless of its actual
-     register number.  */
-  if (mask & (1 << returnreg))
-    {
-      frame->saved_regs[returnreg] = reg_position;
-      reg_position += 8;
-      mask &= ~(1 << returnreg);	/* Clear bit for RA so we
-					   don't save again later. */
-    }
-
-  for (ireg = 0; ireg <= 31; ireg++)
-    if (mask & (1 << ireg))
-      {
-	frame->saved_regs[ireg] = reg_position;
-	reg_position += 8;
-      }
-
-  /* Fill in the offsets for the registers which float_mask says
-     were saved.  */
-
-  reg_position = frame->frame + PROC_FREG_OFFSET (proc_desc);
-  mask = PROC_FREG_MASK (proc_desc);
-
-  for (ireg = 0; ireg <= 31; ireg++)
-    if (mask & (1 << ireg))
-      {
-	frame->saved_regs[FP0_REGNUM + ireg] = reg_position;
-	reg_position += 8;
-      }
-
-  frame->saved_regs[PC_REGNUM] = frame->saved_regs[returnreg];
-}
-
-static CORE_ADDR
-read_next_frame_reg (fi, regno)
-     struct frame_info *fi;
-     int regno;
-{
-  CORE_ADDR result;
-  for (; fi; fi = fi->next)
-    {
-      /* We have to get the saved sp from the sigcontext
-         if it is a signal handler frame.  */
-      if (regno == SP_REGNUM)
-	return fi->frame;
-      else
-	{
-	  if (fi->saved_regs == 0)
-	    alpha_find_saved_regs (fi);
-
-	  if (fi->saved_regs[regno])
-	    {
-	      if (read_memory_safe8 (fi->saved_regs[regno], &result) == 0)
-		return result;
-	      else
-		return 0;
-	    }
-	}
-    }
-
-  return read_register (regno);
-}
-
-static CORE_ADDR
-alpha_frame_saved_pc (frame)
-     struct frame_info *frame;
-{
-  return read_next_frame_reg (frame, frame->pc_reg);
-}
-
-static struct alpha_extra_func_info temp_proc_desc;
-
-/* Nonzero if instruction at PC is a return instruction.  "ret
-   $zero,($ra),1" on alpha. */
-
-static int
-alpha_about_to_return (pc)
-     CORE_ADDR pc;
-{
-  int inst;
-
-  read_memory_safe4 (pc, &inst);
-  return inst == 0x6bfa8001;
-}
-
-/* A heuristically computed start address for the subprogram
-   containing address PC.   Returns 0 if none detected. */
-
-static CORE_ADDR
-heuristic_proc_start (pc)
-     CORE_ADDR pc;
-{
-  CORE_ADDR start_pc = pc;
-  CORE_ADDR fence = start_pc - heuristic_fence_post;
-
-  if (start_pc == 0)
-    return 0;
-
-  if (heuristic_fence_post == UINT_MAX
-      || fence < VM_MIN_ADDRESS)
-    fence = VM_MIN_ADDRESS;
-
-  /* search back for previous return */
-  for (start_pc -= 4; ; start_pc -= 4)
-    {
-      if (start_pc < fence)
-	return 0;
-      else if (alpha_about_to_return (start_pc))
-	break;
-    }
-
-  start_pc += 4;		/* skip return */
-  return start_pc;
-}
-
-static alpha_extra_func_info_t
-heuristic_proc_desc (start_pc, limit_pc, next_frame, saved_regs_p)
-     CORE_ADDR start_pc;
-     CORE_ADDR limit_pc;
-     struct frame_info *next_frame;
-     struct frame_saved_regs *saved_regs_p;
-{
-  CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM);
-  CORE_ADDR cur_pc;
-  int frame_size;
-  int has_frame_reg = 0;
-  unsigned long reg_mask = 0;
-  int pcreg = -1;
-
-  if (start_pc == 0)
-    return 0;
-
-  memset (&temp_proc_desc, '\0', sizeof (temp_proc_desc));
-  if (saved_regs_p != 0)
-    memset (saved_regs_p, '\0', sizeof (struct frame_saved_regs));
-
-  PROC_LOW_ADDR (&temp_proc_desc) = start_pc;
-
-  if (start_pc + 200 < limit_pc)
-    limit_pc = start_pc + 200;
-
-  frame_size = 0;
-  for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += 4)
-    {
-      unsigned int word;
-      int status;
-
-      status = read_memory_safe4 (cur_pc, &word);
-      if (status)
-	return 0;
-
-      if ((word & 0xffff0000) == 0x23de0000)	/* lda $sp,n($sp) */
-	{
-	  if (word & 0x8000)
-	    frame_size += (-word) & 0xffff;
-	  else
-	    /* Exit loop if a positive stack adjustment is found, which
-	       usually means that the stack cleanup code in the function
-	       epilogue is reached.  */
-	    break;
-	}
-      else if ((word & 0xfc1f0000) == 0xb41e0000	/* stq reg,n($sp) */
-	       && (word & 0xffff0000) != 0xb7fe0000)	/* reg != $zero */
-	{
-	  int reg = (word & 0x03e00000) >> 21;
-
-	  reg_mask |= 1 << reg;
-	  if (saved_regs_p != 0)
-	    saved_regs_p->regs[reg] = sp + (short) word;
-
-	  /* Starting with OSF/1-3.2C, the system libraries are shipped
-	     without local symbols, but they still contain procedure
-	     descriptors without a symbol reference. GDB is currently
-	     unable to find these procedure descriptors and uses
-	     heuristic_proc_desc instead.
-	     As some low level compiler support routines (__div*, __add*)
-	     use a non-standard return address register, we have to
-	     add some heuristics to determine the return address register,
-	     or stepping over these routines will fail.
-	     Usually the return address register is the first register
-	     saved on the stack, but assembler optimization might
-	     rearrange the register saves.
-	     So we recognize only a few registers (t7, t9, ra) within
-	     the procedure prologue as valid return address registers.
-	     If we encounter a return instruction, we extract the
-	     the return address register from it.
-
-	     FIXME: Rewriting GDB to access the procedure descriptors,
-	     e.g. via the minimal symbol table, might obviate this hack.  */
-	  if (pcreg == -1
-	      && cur_pc < (start_pc + 80)
-	      && (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM))
-	    pcreg = reg;
-	}
-      else if ((word & 0xffe0ffff) == 0x6be08001)	/* ret zero,reg,1 */
-	pcreg = (word >> 16) & 0x1f;
-      else if (word == 0x47de040f)	/* bis sp,sp fp */
-	has_frame_reg = 1;
-    }
-
-  if (pcreg == -1)
-    {
-      /* If we haven't found a valid return address register yet,
-         keep searching in the procedure prologue.  */
-      while (cur_pc < (limit_pc + 80) && cur_pc < (start_pc + 80))
-	{
-	  unsigned int word;
-
-	  if (read_memory_safe4 (cur_pc, &word))
-	    break;
-	  cur_pc += 4;
-
-	  if ((word & 0xfc1f0000) == 0xb41e0000		/* stq reg,n($sp) */
-	      && (word & 0xffff0000) != 0xb7fe0000)	/* reg != $zero */
-	    {
-	      int reg = (word & 0x03e00000) >> 21;
-
-	      if (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM)
-		{
-		  pcreg = reg;
-		  break;
-		}
-	    }
-	  else if ((word & 0xffe0ffff) == 0x6be08001)	/* ret zero,reg,1 */
-	    {
-	      pcreg = (word >> 16) & 0x1f;
-	      break;
-	    }
-	}
-    }
-
-  if (has_frame_reg)
-    PROC_FRAME_REG (&temp_proc_desc) = GCC_FP_REGNUM;
-  else
-    PROC_FRAME_REG (&temp_proc_desc) = SP_REGNUM;
-
-  PROC_FRAME_OFFSET (&temp_proc_desc) = frame_size;
-  PROC_REG_MASK (&temp_proc_desc) = reg_mask;
-  PROC_PC_REG (&temp_proc_desc) = (pcreg == -1) ? RA_REGNUM : pcreg;
-  PROC_LOCALOFF (&temp_proc_desc) = 0;	/* XXX - bogus */
-
-  return &temp_proc_desc;
-}
-
-static alpha_extra_func_info_t
-find_proc_desc (pc, next_frame, saved_regs)
-     CORE_ADDR pc;
-     struct frame_info *next_frame;
-     struct frame_saved_regs *saved_regs;
-{
-  CORE_ADDR startaddr;
-
-  /* If heuristic_fence_post is non-zero, determine the procedure
-     start address by examining the instructions.
-     This allows us to find the start address of static functions which
-     have no symbolic information, as startaddr would have been set to
-     the preceding global function start address by the
-     find_pc_partial_function call above.  */
-  startaddr = heuristic_proc_start (pc);
-
-  return heuristic_proc_desc (startaddr, pc, next_frame, saved_regs);
-}
-
-static CORE_ADDR
-alpha_frame_chain (frame)
-     struct frame_info *frame;
-{
-  alpha_extra_func_info_t proc_desc;
-  CORE_ADDR saved_pc = FRAME_SAVED_PC (frame);
-
-  if (saved_pc == 0 || inside_entry_file (saved_pc))
-    return 0;
-
-  proc_desc = find_proc_desc (saved_pc, frame, NULL);
-  if (!proc_desc)
-    return 0;
-
-  /* If no frame pointer and frame size is zero, we must be at end
-     of stack (or otherwise hosed).  If we don't check frame size,
-     we loop forever if we see a zero size frame.  */
-  if (PROC_FRAME_REG (proc_desc) == SP_REGNUM
-      && PROC_FRAME_OFFSET (proc_desc) == 0)
-    return 0;
-  else
-    return read_next_frame_reg (frame, PROC_FRAME_REG (proc_desc))
-      + PROC_FRAME_OFFSET (proc_desc);
-}
-
-static void
-init_extra_frame_info (frame)
-     struct frame_info *frame;
-{
-  struct frame_saved_regs temp_saved_regs;
-  alpha_extra_func_info_t proc_desc = 
-    find_proc_desc (frame->pc, frame->next, &temp_saved_regs);
-
-  frame->saved_regs = NULL;
-  frame->localoff = 0;
-  frame->pc_reg = RA_REGNUM;
-  frame->proc_desc = proc_desc;
-
-  if (proc_desc)
-    {
-      /* Get the locals offset and the saved pc register from the
-         procedure descriptor, they are valid even if we are in the
-         middle of the prologue.  */
-      frame->localoff = PROC_LOCALOFF (proc_desc);
-      frame->pc_reg = PROC_PC_REG (proc_desc);
-
-      /* Fixup frame-pointer - only needed for top frame */
-
-      /* This may not be quite right, if proc has a real frame register.
-         Get the value of the frame relative sp, procedure might have been
-         interrupted by a signal at it's very start.  */
-      if (frame->pc == PROC_LOW_ADDR (proc_desc))
-	frame->frame = read_next_frame_reg (frame->next, SP_REGNUM);
-      else
-	frame->frame
-	  = (read_next_frame_reg (frame->next, PROC_FRAME_REG (proc_desc))
-	     + PROC_FRAME_OFFSET (proc_desc));
-
-      frame->saved_regs
-	= (CORE_ADDR *) frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
-      memcpy
-        (frame->saved_regs, temp_saved_regs.regs, SIZEOF_FRAME_SAVED_REGS);
-      frame->saved_regs[PC_REGNUM] = frame->saved_regs[RA_REGNUM];
-    }
-}
-
-/* Create an arbitrary (i.e. address specified by user) or innermost frame.
-   Always returns a non-NULL value.  */
-
-static struct frame_info *
-create_new_frame (addr, pc)
-     CORE_ADDR addr;
-     CORE_ADDR pc;
-{
-  struct frame_info *fi;
-
-  fi = (struct frame_info *)
-    trace_alloc (sizeof (struct frame_info));
-
-  /* Arbitrary frame */
-  fi->next = NULL;
-  fi->prev = NULL;
-  fi->frame = addr;
-  fi->pc = pc;
-
-#ifdef INIT_EXTRA_FRAME_INFO
-  INIT_EXTRA_FRAME_INFO (0, fi);
-#endif
-
-  return fi;
-}
-
-static CORE_ADDR current_pc;
-
-static void
-set_current_pc ()
-{
-  current_pc = (CORE_ADDR) __builtin_return_address (0);
-}
-
-static CORE_ADDR
-read_pc ()
-{
-  return current_pc;
-}
-
-static struct frame_info *
-get_current_frame ()
-{
-  return create_new_frame (0, read_pc ());
-}
-
-/* Return the frame that called FI.
-   If FI is the original frame (it has no caller), return 0.  */
-
-static struct frame_info *
-get_prev_frame (next_frame)
-     struct frame_info *next_frame;
-{
-  CORE_ADDR address = 0;
-  struct frame_info *prev;
-  int fromleaf = 0;
-
-  /* If we have the prev one, return it */
-  if (next_frame->prev)
-    return next_frame->prev;
-
-  /* On some machines it is possible to call a function without
-     setting up a stack frame for it.  On these machines, we
-     define this macro to take two args; a frameinfo pointer
-     identifying a frame and a variable to set or clear if it is
-     or isn't leafless.  */
-
-  /* Two macros defined in tm.h specify the machine-dependent
-     actions to be performed here.
-
-     First, get the frame's chain-pointer.  If that is zero, the frame
-     is the outermost frame or a leaf called by the outermost frame.
-     This means that if start calls main without a frame, we'll return
-     0 (which is fine anyway).
-
-     Nope; there's a problem.  This also returns when the current
-     routine is a leaf of main.  This is unacceptable.  We move
-     this to after the ffi test; I'd rather have backtraces from
-     start go curfluy than have an abort called from main not show
-     main.  */
-
-  address = FRAME_CHAIN (next_frame);
-  if (!FRAME_CHAIN_VALID (address, next_frame))
-    return 0;
-  address = FRAME_CHAIN_COMBINE (address, next_frame);
-
-  if (address == 0)
-    return 0;
-
-  prev = (struct frame_info *) trace_alloc (sizeof (struct frame_info));
-
-  prev->saved_regs = NULL;
-  if (next_frame)
-    next_frame->prev = prev;
-
-  prev->next = next_frame;
-  prev->prev = (struct frame_info *) 0;
-  prev->frame = address;
-
-  /* This change should not be needed, FIXME!  We should
-     determine whether any targets *need* INIT_FRAME_PC to happen
-     after INIT_EXTRA_FRAME_INFO and come up with a simple way to
-     express what goes on here.
-
-     INIT_EXTRA_FRAME_INFO is called from two places: create_new_frame
-     (where the PC is already set up) and here (where it isn't).
-     INIT_FRAME_PC is only called from here, always after
-     INIT_EXTRA_FRAME_INFO.
-
-     The catch is the MIPS, where INIT_EXTRA_FRAME_INFO requires the PC
-     value (which hasn't been set yet).  Some other machines appear to
-     require INIT_EXTRA_FRAME_INFO before they can do INIT_FRAME_PC.  Phoo.
-
-     We shouldn't need INIT_FRAME_PC_FIRST to add more complication to
-     an already overcomplicated part of GDB.   gnu@cygnus.com, 15Sep92.
-
-     Assuming that some machines need INIT_FRAME_PC after
-     INIT_EXTRA_FRAME_INFO, one possible scheme:
-
-     SETUP_INNERMOST_FRAME()
-     Default version is just create_new_frame (read_fp ()),
-     read_pc ()).  Machines with extra frame info would do that (or the
-     local equivalent) and then set the extra fields.
-     INIT_PREV_FRAME(fromleaf, prev)
-     Replace INIT_EXTRA_FRAME_INFO and INIT_FRAME_PC.  This should
-     also return a flag saying whether to keep the new frame, or
-     whether to discard it, because on some machines (e.g.  mips) it
-     is really awkward to have FRAME_CHAIN_VALID called *before*
-     INIT_EXTRA_FRAME_INFO (there is no good way to get information
-     deduced in FRAME_CHAIN_VALID into the extra fields of the new frame).
-     std_frame_pc(fromleaf, prev)
-     This is the default setting for INIT_PREV_FRAME.  It just does what
-     the default INIT_FRAME_PC does.  Some machines will call it from
-     INIT_PREV_FRAME (either at the beginning, the end, or in the middle).
-     Some machines won't use it.
-     kingdon@cygnus.com, 13Apr93, 31Jan94, 14Dec94.  */
-
-#ifdef INIT_FRAME_PC_FIRST
-  INIT_FRAME_PC_FIRST (fromleaf, prev);
-#endif
-
-#ifdef INIT_EXTRA_FRAME_INFO
-  INIT_EXTRA_FRAME_INFO (fromleaf, prev);
 #endif
 
-  /* This entry is in the frame queue now, which is good since
-     FRAME_SAVED_PC may use that queue to figure out its value
-     (see tm-sparc.h).  We want the pc saved in the inferior frame. */
-  INIT_FRAME_PC (fromleaf, prev);
-
-  /* If ->frame and ->pc are unchanged, we are in the process of getting
-     ourselves into an infinite backtrace.  Some architectures check this
-     in FRAME_CHAIN or thereabouts, but it seems like there is no reason
-     this can't be an architecture-independent check.  */
-  if (next_frame != NULL)
-    {
-      if (prev->frame == next_frame->frame
-	  && prev->pc == next_frame->pc)
-	{
-	  next_frame->prev = NULL;
-	  free (prev);
-	  return NULL;
-	}
-    }
-
-  return prev;
-}
-
-#define SAVE(regno,disp) \
-    "stq $" #regno ", " #disp "(%0)\n" 
-
-int
-__gnat_backtrace (array, size, exclude_min, exclude_max)
-     void **array;
-     int size;
-     void *exclude_min;
-     void *exclude_max;
-{
-  struct frame_info* top;
-  struct frame_info* current;
-  int cnt;
-
-  /* This function is not thread safe, protect it */
-  (*Lock_Task) ();
-  asm volatile (
-      SAVE (9,72)
-      SAVE (10,80)
-      SAVE (11,88)
-      SAVE (12,96)
-      SAVE (13,104)
-      SAVE (14,112)
-      SAVE (15,120)
-      SAVE (16,128)
-      SAVE (17,136)
-      SAVE (18,144)
-      SAVE (19,152)
-      SAVE (20,160)
-      SAVE (21,168)
-      SAVE (22,176)
-      SAVE (23,184)
-      SAVE (24,192)
-      SAVE (25,200)
-      SAVE (26,208)
-      SAVE (27,216)
-      SAVE (28,224)
-      SAVE (29,232)
-      SAVE (30,240)
-      : : "r" (&theRegisters));
-
-  trace_alloc_chain = NULL;
-  set_current_pc ();
-
-  top = current = get_current_frame ();
-  cnt = 0;
-
-  /* We skip the call to this function, it makes no sense to record it.  */
-  for (cnt = 0; cnt < SKIP_FRAME; cnt += 1) {
-    current = get_prev_frame (current);
-  }
-
-  cnt = 0;
-  while (cnt < size)
-    {
-      if (STOP_FRAME)
-        break;
-
-      if (current->pc < (CORE_ADDR) exclude_min
-	  || current->pc > (CORE_ADDR) exclude_max)
-        array[cnt++] = (void*) (current->pc + PC_ADJUST);
-
-      current = get_prev_frame (current);
-    }
-
-  free_trace_alloc ();
-  (*Unlock_Task) ();
-
-  return cnt;
-}
 #endif