samba-mirror/buildtools/wafsamba/samba_deps.py

# Samba automatic dependency handling and project rules

import Build, os, re, Environment, Logs
from samba_utils import *
from samba_autoconf import *
from samba_bundled import BUILTIN_LIBRARY

@conf
def ADD_GLOBAL_DEPENDENCY(ctx, dep):
    '''add a dependency for all binaries and libraries'''
    if not 'GLOBAL_DEPENDENCIES' in ctx.env:
        ctx.env.GLOBAL_DEPENDENCIES = []
    ctx.env.GLOBAL_DEPENDENCIES.append(dep)


def TARGET_ALIAS(bld, target, alias):
    '''define an alias for a target name'''
    cache = LOCAL_CACHE(bld, 'TARGET_ALIAS')
    if alias in cache:
        Logs.error("Target alias %s already set to %s : newalias %s" % (alias, cache[alias], target))
        sys.exit(1)
    cache[alias] = target
Build.BuildContext.TARGET_ALIAS = TARGET_ALIAS


@conf
def SET_SYSLIB_DEPS(conf, target, deps):
    '''setup some implied dependencies for a SYSLIB'''
    cache = LOCAL_CACHE(conf, 'SYSLIB_DEPS')
    cache[target] = deps


def EXPAND_ALIAS(bld, target):
    '''expand a target name via an alias'''
    aliases = LOCAL_CACHE(bld, 'TARGET_ALIAS')
    if target in aliases:
        return aliases[target]
    return target
Build.BuildContext.EXPAND_ALIAS = EXPAND_ALIAS


def expand_subsystem_deps(bld):
    '''expand the reverse dependencies resulting from subsystem
       attributes of modules'''
    subsystems = LOCAL_CACHE(bld, 'INIT_FUNCTIONS')
    aliases    = LOCAL_CACHE(bld, 'TARGET_ALIAS')
    targets    = LOCAL_CACHE(bld, 'TARGET_TYPE')

    for s in subsystems:
        if s in aliases:
            s = aliases[s]
        bld.ASSERT(s in targets, "Subsystem target %s not declared" % s)
        type = targets[s]
        if type == 'DISABLED' or type == 'EMPTY':
            continue

        t = bld.name_to_obj(s, bld.env)
        for d in subsystems[s]:
            type = targets[d['TARGET']]
            if type != 'DISABLED' and type != 'EMPTY':
                bld.ASSERT(t is not None,
                    "Subsystem target %s for %s (%s) not found" % (s, d['TARGET'], type))
                t.samba_deps_extended.append(d['TARGET'])
                t2 = bld.name_to_obj(d['TARGET'], bld.env)
                t2.samba_includes_extended.extend(t.samba_includes_extended)
                t2.samba_deps_extended.extend(t.samba_deps_extended)
        t.samba_deps_extended = unique_list(t.samba_deps_extended)



def build_dependencies(self):
    '''This builds the dependency list for a target. It runs after all the targets are declared

    The reason this is not just done in the SAMBA_*() rules is that we have no way of knowing
    the full dependency list for a target until we have all of the targets declared.
    '''

    if self.samba_type in ['LIBRARY', 'BINARY', 'PYTHON']:
        self.uselib        = list(self.final_syslibs)
        self.uselib_local  = list(self.final_libs)
        self.add_objects   = list(self.final_objects)

        # extra link flags from pkg_config
        libs = self.final_syslibs.copy()

        (ccflags, ldflags) = library_flags(self, list(libs))
        new_ldflags        = getattr(self, 'ldflags', [])
        new_ldflags.extend(ldflags)
        self.ldflags       = new_ldflags

        debug('deps: computed dependencies for target %s: uselib=%s uselib_local=%s add_objects=%s',
              self.sname, self.uselib, self.uselib_local, self.add_objects)

    if self.samba_type in ['SUBSYSTEM']:
        # this is needed for the ccflags of libs that come from pkg_config
        self.uselib = list(self.direct_syslibs)

    if getattr(self, 'uselib', None):
        up_list = []
        for l in self.uselib:
           up_list.append(l.upper())
        self.uselib = up_list

def build_includes(self):
    '''This builds the right set of includes for a target.

    One tricky part of this is that the includes= attribute for a
    target needs to use paths which are relative to that targets
    declaration directory (which we can get at via t.path).

    The way this works is the includes list gets added as
    samba_includes in the main build task declaration. Then this
    function runs after all of the tasks are declared, and it
    processes the samba_includes attribute to produce a includes=
    attribute
    '''

    if getattr(self, 'samba_includes', None) is None:
        return

    bld = self.bld

    inc_deps = includes_objects(bld, self, set(), {})

    includes = []

    # maybe add local includes
    if getattr(self, 'local_include', True) == True and getattr(self, 'local_include_first', True):
        includes.append('.')

    includes.extend(self.samba_includes_extended)

    if 'EXTRA_INCLUDES' in bld.env:
        includes.extend(bld.env['EXTRA_INCLUDES'])

    includes.append('#')

    inc_set = set()
    inc_abs = []

    for d in inc_deps:
        t = bld.name_to_obj(d, bld.env)
        bld.ASSERT(t is not None, "Unable to find dependency %s for %s" % (d, self.sname))
        inclist = getattr(t, 'samba_includes_extended', [])
        if getattr(t, 'local_include', True) == True:
            inclist.append('.')
        if inclist == []:
            continue
        tpath = t.samba_abspath
        for inc in inclist:
            npath = tpath + '/' + inc
            if not npath in inc_set:
                inc_abs.append(npath)
                inc_set.add(npath)

    mypath = self.path.abspath(bld.env)
    for inc in inc_abs:
        relpath = os_path_relpath(inc, mypath)
        includes.append(relpath)

    if getattr(self, 'local_include', True) == True and not getattr(self, 'local_include_first', True):
        includes.append('.')

    # now transform the includes list to be relative to the top directory
    # which is represented by '#' in waf. This allows waf to cache the
    # includes lists more efficiently
    includes_top = []
    for i in includes:
        if i[0] == '#':
            # some are already top based
            includes_top.append(i)
            continue
        absinc = os.path.join(self.path.abspath(), i)
        relinc = os_path_relpath(absinc, self.bld.srcnode.abspath())
        includes_top.append('#' + relinc)

    self.includes = unique_list(includes_top)
    debug('deps: includes for target %s: includes=%s',
          self.sname, self.includes)




def add_init_functions(self):
    '''This builds the right set of init functions'''

    bld = self.bld

    subsystems = LOCAL_CACHE(bld, 'INIT_FUNCTIONS')

    # cope with the separated object lists from BINARY and LIBRARY targets
    sname = self.sname
    if sname.endswith('.objlist'):
        sname = sname[0:-8]

    modules = []
    if sname in subsystems:
        modules.append(sname)

    m = getattr(self, 'samba_modules', None)
    if m is not None:
        modules.extend(TO_LIST(m))

    m = getattr(self, 'samba_subsystem', None)
    if m is not None:
        modules.append(m)

    if modules == []:
        return

    sentinal = getattr(self, 'init_function_sentinal', 'NULL')

    targets    = LOCAL_CACHE(bld, 'TARGET_TYPE')

    cflags = getattr(self, 'samba_cflags', [])[:]
    for m in modules:
        bld.ASSERT(m in subsystems,
                   "No init_function defined for module '%s' in target '%s'" % (m, self.sname))
        init_fn_list = []
        for d in subsystems[m]:
            if targets[d['TARGET']] != 'DISABLED':
                init_fn_list.append(d['INIT_FUNCTION'])
        if init_fn_list == []:
            cflags.append('-DSTATIC_%s_MODULES=%s' % (m, sentinal))
        else:
            cflags.append('-DSTATIC_%s_MODULES=%s' % (m, ','.join(init_fn_list) + ',' + sentinal))
    self.ccflags = cflags



def check_duplicate_sources(bld, tgt_list):
    '''see if we are compiling the same source file into multiple
    subsystem targets for the same library or binary'''

    debug('deps: checking for duplicate sources')

    targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
    ret = True

    seen = set()

    for t in tgt_list:
        obj_sources = getattr(t, 'source', '')
        tpath = os.path.normpath(os_path_relpath(t.path.abspath(bld.env), t.env.BUILD_DIRECTORY + '/default'))
        obj_sources = bld.SUBDIR(tpath, obj_sources)
        t.samba_source_set = set(TO_LIST(obj_sources))

    for t in tgt_list:
        if not targets[t.sname] in [ 'LIBRARY', 'BINARY', 'PYTHON' ]:
            continue

        sources = []
        for obj in t.add_objects:
            t2 = t.bld.name_to_obj(obj, bld.env)
            source_set = getattr(t2, 'samba_source_set', set())
            sources.append( { 'dep':obj, 'src':source_set} )
        for s in sources:
            for s2 in sources:
                if s['dep'] == s2['dep']: continue
                common = s['src'].intersection(s2['src'])
                if common.difference(seen):
                    Logs.error("Target %s has duplicate source files in %s and %s : %s" % (t.sname,
                                                                                      s['dep'], s2['dep'],
                                                                                      common))
                    seen = seen.union(common)
                    ret = False
    return ret


def check_orpaned_targets(bld, tgt_list):
    '''check if any build targets are orphaned'''

    target_dict = LOCAL_CACHE(bld, 'TARGET_TYPE')

    debug('deps: checking for orphaned targets')

    for t in tgt_list:
        if getattr(t, 'samba_used', False) == True:
            continue
        type = target_dict[t.sname]
        if not type in ['BINARY', 'LIBRARY', 'MODULE', 'ET', 'PYTHON']:
            if re.search('^PIDL_', t.sname) is None:
                Logs.warn("Target %s of type %s is unused by any other target" % (t.sname, type))


def check_group_ordering(bld, tgt_list):
    '''see if we have any dependencies that violate the group ordering

    It is an error for a target to depend on a target from a later
    build group
    '''

    def group_name(g):
        tm = bld.task_manager
        return [x for x in tm.groups_names if id(tm.groups_names[x]) == id(g)][0]

    for g in bld.task_manager.groups:
        gname = group_name(g)
        for t in g.tasks_gen:
            t.samba_group = gname

    grp_map = {}
    idx = 0
    for g in bld.task_manager.groups:
        name = group_name(g)
        grp_map[name] = idx
        idx += 1

    targets = LOCAL_CACHE(bld, 'TARGET_TYPE')

    ret = True
    for t in tgt_list:
        tdeps = getattr(t, 'add_objects', []) + getattr(t, 'uselib_local', [])
        for d in tdeps:
            t2 = bld.name_to_obj(d, bld.env)
            if t2 is None:
                continue
            map1 = grp_map[t.samba_group]
            map2 = grp_map[t2.samba_group]

            if map2 > map1:
                Logs.error("Target %r in build group %r depends on target %r from later build group %r" % (
                           t.sname, t.samba_group, t2.sname, t2.samba_group))
                ret = False

    return ret


def show_final_deps(bld, tgt_list):
    '''show the final dependencies for all targets'''

    targets = LOCAL_CACHE(bld, 'TARGET_TYPE')

    for t in tgt_list:
        if not targets[t.sname] in ['LIBRARY', 'BINARY', 'PYTHON']:
            continue
        debug('deps: final dependencies for target %s: uselib=%s uselib_local=%s add_objects=%s',
              t.sname, t.uselib, t.uselib_local, t.add_objects)


def add_samba_attributes(bld, tgt_list):
    '''ensure a target has a the required samba attributes'''

    targets = LOCAL_CACHE(bld, 'TARGET_TYPE')

    for t in tgt_list:
        if t.name != '':
            t.sname = t.name
        else:
            t.sname = t.target
        t.samba_type = targets[t.sname]
        t.samba_abspath = t.path.abspath(bld.env)
        t.samba_deps_extended = t.samba_deps[:]
        t.samba_includes_extended = TO_LIST(t.samba_includes)[:]
        t.ccflags = getattr(t, 'samba_cflags', '')


def build_direct_deps(bld, tgt_list):
    '''build the direct_objects and direct_libs sets for each target'''

    targets  = LOCAL_CACHE(bld, 'TARGET_TYPE')
    syslib_deps  = LOCAL_CACHE(bld, 'SYSLIB_DEPS')
    global_deps = bld.env.GLOBAL_DEPENDENCIES

    for t in tgt_list:
        t.direct_objects = set()
        t.direct_libs = set()
        t.direct_syslibs = set()
        deps = t.samba_deps_extended
        if getattr(t, 'samba_use_global_deps', False):
            deps.extend(global_deps)
        for d in deps:
            d = EXPAND_ALIAS(bld, d)
            if d == t.sname: continue
            if not d in targets:
                Logs.error("Unknown dependency %s in %s" % (d, t.sname))
                sys.exit(1)
            if targets[d] in [ 'EMPTY', 'DISABLED' ]:
                continue
            if targets[d] == 'SYSLIB':
                t.direct_syslibs.add(d)
                if d in syslib_deps:
                    for implied in TO_LIST(syslib_deps[d]):
                        if BUILTIN_LIBRARY(bld, implied):
                            t.direct_objects.add(implied)
                        elif targets[implied] == 'SYSLIB':
                            t.direct_syslibs.add(implied)
                        elif targets[implied] in ['LIBRARY', 'MODULE']:
                            t.direct_libs.add(implied)
                        else:
                            Logs.error('Implied dependency %s in %s is of type %s' % (
                                implied, t.sname, targets[implied]))
                            sys.exit(1)
                continue
            t2 = bld.name_to_obj(d, bld.env)
            if t2 is None:
                Logs.error("no task %s of type %s in %s" % (d, targets[d], t.sname))
                sys.exit(1)
            if t2.samba_type in [ 'LIBRARY', 'MODULE' ]:
                t.direct_libs.add(d)
            elif t2.samba_type in [ 'SUBSYSTEM', 'ASN1', 'PYTHON' ]:
                t.direct_objects.add(d)
    debug('deps: built direct dependencies')


def dependency_loop(loops, t, target):
    '''add a dependency loop to the loops dictionary'''
    if t.sname == target:
        return
    if not target in loops:
        loops[target] = set()
    if not t.sname in loops[target]:
        loops[target].add(t.sname)


def indirect_libs(bld, t, chain, loops):
    '''recursively calculate the indirect library dependencies for a target

    An indirect library is a library that results from a dependency on
    a subsystem
    '''

    ret = getattr(t, 'indirect_libs', None)
    if ret is not None:
        return ret

    ret = set()
    for obj in t.direct_objects:
        if obj in chain:
            dependency_loop(loops, t, obj)
            continue
        chain.add(obj)
        t2 = bld.name_to_obj(obj, bld.env)
        r2 = indirect_libs(bld, t2, chain, loops)
        chain.remove(obj)
        ret = ret.union(t2.direct_libs)
        ret = ret.union(r2)

    for obj in indirect_objects(bld, t, set(), loops):
        if obj in chain:
            dependency_loop(loops, t, obj)
            continue
        chain.add(obj)
        t2 = bld.name_to_obj(obj, bld.env)
        r2 = indirect_libs(bld, t2, chain, loops)
        chain.remove(obj)
        ret = ret.union(t2.direct_libs)
        ret = ret.union(r2)

    t.indirect_libs = ret

    return ret


def indirect_objects(bld, t, chain, loops):
    '''recursively calculate the indirect object dependencies for a target

    indirect objects are the set of objects from expanding the
    subsystem dependencies
    '''

    ret = getattr(t, 'indirect_objects', None)
    if ret is not None: return ret

    ret = set()
    for lib in t.direct_objects:
        if lib in chain:
            dependency_loop(loops, t, lib)
            continue
        chain.add(lib)
        t2 = bld.name_to_obj(lib, bld.env)
        r2 = indirect_objects(bld, t2, chain, loops)
        chain.remove(lib)
        ret = ret.union(t2.direct_objects)
        ret = ret.union(r2)

    t.indirect_objects = ret
    return ret


def extended_objects(bld, t, chain):
    '''recursively calculate the extended object dependencies for a target

    extended objects are the union of:
       - direct objects
       - indirect objects
       - direct and indirect objects of all direct and indirect libraries
    '''

    ret = getattr(t, 'extended_objects', None)
    if ret is not None: return ret

    ret = set()
    ret = ret.union(t.final_objects)

    for lib in t.final_libs:
        if lib in chain:
            continue
        t2 = bld.name_to_obj(lib, bld.env)
        chain.add(lib)
        r2 = extended_objects(bld, t2, chain)
        chain.remove(lib)
        ret = ret.union(t2.final_objects)
        ret = ret.union(r2)

    t.extended_objects = ret
    return ret


def includes_objects(bld, t, chain, inc_loops):
    '''recursively calculate the includes object dependencies for a target

    includes dependencies come from either library or object dependencies
    '''
    ret = getattr(t, 'includes_objects', None)
    if ret is not None:
        return ret

    ret = t.direct_objects.copy()
    ret = ret.union(t.direct_libs)

    for obj in t.direct_objects:
        if obj in chain:
            dependency_loop(inc_loops, t, obj)
            continue
        chain.add(obj)
        t2 = bld.name_to_obj(obj, bld.env)
        r2 = includes_objects(bld, t2, chain, inc_loops)
        chain.remove(obj)
        ret = ret.union(t2.direct_objects)
        ret = ret.union(r2)

    for lib in t.direct_libs:
        if lib in chain:
            dependency_loop(inc_loops, t, lib)
            continue
        chain.add(lib)
        t2 = bld.name_to_obj(lib, bld.env)
        if t2 is None:
            targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
            Logs.error('Target %s of type %s not found in direct_libs for %s' % (
                lib, targets[lib], t.sname))
            sys.exit(1)
        r2 = includes_objects(bld, t2, chain, inc_loops)
        chain.remove(lib)
        ret = ret.union(t2.direct_objects)
        ret = ret.union(r2)

    t.includes_objects = ret
    return ret


def break_dependency_loops(bld, tgt_list):
    '''find and break dependency loops'''
    loops = {}
    inc_loops = {}

    # build up the list of loops
    for t in tgt_list:
        indirect_objects(bld, t, set(), loops)
        indirect_libs(bld, t, set(), loops)
        includes_objects(bld, t, set(), inc_loops)

    # break the loops
    for t in tgt_list:
        if t.sname in loops:
            for attr in ['direct_objects', 'indirect_objects', 'direct_libs', 'indirect_libs']:
                objs = getattr(t, attr, set())
                setattr(t, attr, objs.difference(loops[t.sname]))

    for loop in loops:
        debug('deps: Found dependency loops for target %s : %s', loop, loops[loop])

    for loop in inc_loops:
        debug('deps: Found include loops for target %s : %s', loop, inc_loops[loop])

    # expand the loops mapping by one level
    for loop in loops.copy():
        for tgt in loops[loop]:
            if tgt in loops:
                loops[loop] = loops[loop].union(loops[tgt])

    for loop in inc_loops.copy():
        for tgt in inc_loops[loop]:
            if tgt in inc_loops:
                inc_loops[loop] = inc_loops[loop].union(inc_loops[tgt])


    # expand indirect subsystem and library loops
    for loop in loops.copy():
        t = bld.name_to_obj(loop, bld.env)
        if t.samba_type in ['SUBSYSTEM']:
            loops[loop] = loops[loop].union(t.indirect_objects)
            loops[loop] = loops[loop].union(t.direct_objects)
        if t.samba_type in ['LIBRARY','PYTHON']:
            loops[loop] = loops[loop].union(t.indirect_libs)
            loops[loop] = loops[loop].union(t.direct_libs)
        if loop in loops[loop]:
            loops[loop].remove(loop)

    # expand indirect includes loops
    for loop in inc_loops.copy():
        t = bld.name_to_obj(loop, bld.env)
        inc_loops[loop] = inc_loops[loop].union(t.includes_objects)
        if loop in inc_loops[loop]:
            inc_loops[loop].remove(loop)

    # add in the replacement dependencies
    for t in tgt_list:
        for loop in loops:
            for attr in ['direct_objects', 'indirect_objects', 'direct_libs', 'indirect_libs']:
                objs = getattr(t, attr, set())
                if loop in objs:
                    diff = loops[loop].difference(objs)
                    if t.sname in diff:
                        diff.remove(t.sname)
                    if diff:
                        debug('deps: Expanded target %s of type %s from loop %s by %s', t.sname, t.samba_type, loop, diff)
                        objs = objs.union(diff)
                setattr(t, attr, objs)

        for loop in inc_loops:
            objs = getattr(t, 'includes_objects', set())
            if loop in objs:
                diff = inc_loops[loop].difference(objs)
                if t.sname in diff:
                    diff.remove(t.sname)
                if diff:
                    debug('deps: Expanded target %s includes of type %s from loop %s by %s', t.sname, t.samba_type, loop, diff)
                    objs = objs.union(diff)
            setattr(t, 'includes_objects', objs)


def reduce_objects(bld, tgt_list):
    '''reduce objects by looking for indirect object dependencies'''
    rely_on = {}

    for t in tgt_list:
        t.extended_objects = None

    changed = False

    for type in ['BINARY', 'PYTHON', 'LIBRARY']:
        for t in tgt_list:
            if t.samba_type != type: continue
            # if we will indirectly link to a target then we don't need it
            new = t.final_objects.copy()
            for l in t.final_libs:
                t2 = bld.name_to_obj(l, bld.env)
                t2_obj = extended_objects(bld, t2, set())
                dup = new.intersection(t2_obj)
                if t.sname in rely_on:
                    dup = dup.difference(rely_on[t.sname])
                if dup:
                    debug('deps: removing dups from %s of type %s: %s also in %s %s',
                          t.sname, t.samba_type, dup, t2.samba_type, l)
                    new = new.difference(dup)
                    changed = True
                    if not l in rely_on:
                        rely_on[l] = set()
                    rely_on[l] = rely_on[l].union(dup)
            t.final_objects = new

    if not changed:
        return False

    # add back in any objects that were relied upon by the reduction rules
    for r in rely_on:
        t = bld.name_to_obj(r, bld.env)
        t.final_objects = t.final_objects.union(rely_on[r])

    return True


def calculate_final_deps(bld, tgt_list, loops):
    '''calculate the final library and object dependencies'''
    for t in tgt_list:
        # start with the maximum possible list
        t.final_libs    = t.direct_libs.union(indirect_libs(bld, t, set(), loops))
        t.final_objects = t.direct_objects.union(indirect_objects(bld, t, set(), loops))

    for t in tgt_list:
        # don't depend on ourselves
        if t.sname in t.final_libs:
            t.final_libs.remove(t.sname)
        if t.sname in t.final_objects:
            t.final_objects.remove(t.sname)

    # handle any non-shared binaries
    for t in tgt_list:
        if t.samba_type == 'BINARY' and bld.NONSHARED_BINARY(t.sname):
            # replace lib deps with objlist deps
            for l in t.final_libs:
                objname = l + '.objlist'
                t2 = bld.name_to_obj(objname, bld.env)
                if t2 is None:
                    Logs.error('ERROR: subsystem %s not found' % objname)
                    sys.exit(1)
                t.final_objects.add(objname)
                t.final_objects = t.final_objects.union(extended_objects(bld, t2, set()))
            t.final_libs = set()

    # find any library loops
    for t in tgt_list:
        if t.samba_type in ['LIBRARY', 'PYTHON']:
            for l in t.final_libs.copy():
                t2 = bld.name_to_obj(l, bld.env)
                if t.sname in t2.final_libs:
                    # we could break this in either direction. If one of the libraries
                    # has a version number, and will this be distributed publicly, then
                    # we should make it the lower level library in the DAG
                    debug('deps: removing library loop %s from %s', t.sname, t2.sname)
                    dependency_loop(loops, t, t2.sname)
                    t2.final_libs.remove(t.sname)


    for loop in loops:
        debug('deps: Found dependency loops for target %s : %s', loop, loops[loop])

    # we now need to make corrections for any library loops we broke up
    # any target that depended on the target of the loop and doesn't
    # depend on the source of the loop needs to get the loop source added
    for type in ['BINARY','PYTHON','LIBRARY','BINARY']:
        for t in tgt_list:
            if t.samba_type != type: continue
            for loop in loops:
                if loop in t.final_libs:
                    diff = loops[loop].difference(t.final_libs)
                    if t.sname in diff:
                        diff.remove(t.sname)
                    if t.sname in diff:
                        diff.remove(t.sname)
                    # make sure we don't recreate the loop again!
                    for d in diff.copy():
                        t2 = bld.name_to_obj(d, bld.env)
                        if t2.samba_type == 'LIBRARY':
                            if t.sname in t2.final_libs:
                                debug('deps: removing expansion %s from %s', d, t.sname)
                                diff.remove(d)
                    if diff:
                        debug('deps: Expanded target %s by loop %s libraries (loop %s) %s', t.sname, loop,
                              loops[loop], diff)
                        t.final_libs = t.final_libs.union(diff)

    # remove objects that are also available in linked libs
    count = 0
    while reduce_objects(bld, tgt_list):
        count += 1
        if count > 100:
            Logs.warn("WARNING: Unable to remove all inter-target object duplicates")
            break
    debug('deps: Object reduction took %u iterations', count)

    # add in any syslib dependencies
    for t in tgt_list:
        if not t.samba_type in ['BINARY','PYTHON','LIBRARY']:
            continue
        syslibs = set()
        for d in t.final_objects:
            t2 = bld.name_to_obj(d, bld.env)
            syslibs = syslibs.union(t2.direct_syslibs)
        # this adds the indirect syslibs as well, which may not be needed
        # depending on the linker flags
        for d in t.final_libs:
            t2 = bld.name_to_obj(d, bld.env)
            syslibs = syslibs.union(t2.direct_syslibs)
        t.final_syslibs = syslibs


    # find any unresolved library loops
    lib_loop_error = False
    for t in tgt_list:
        if t.samba_type in ['LIBRARY', 'PYTHON']:
            for l in t.final_libs.copy():
                t2 = bld.name_to_obj(l, bld.env)
                if t.sname in t2.final_libs:
                    Logs.error('ERROR: Unresolved library loop %s from %s' % (t.sname, t2.sname))
                    lib_loop_error = True
    if lib_loop_error:
        sys.exit(1)

    debug('deps: removed duplicate dependencies')


######################################################################
# this provides a way to save our dependency calculations between runs
savedeps_version = 3
savedeps_inputs  = ['samba_deps', 'samba_includes', 'local_include', 'local_include_first', 'samba_cflags', 'source']
savedeps_outputs = ['uselib', 'uselib_local', 'add_objects', 'includes', 'ccflags']
savedeps_outenv  = ['INC_PATHS']
savedeps_envvars = ['NONSHARED_BINARIES', 'GLOBAL_DEPENDENCIES']
savedeps_caches  = ['GLOBAL_DEPENDENCIES', 'TARGET_ALIAS', 'TARGET_TYPE', 'INIT_FUNCTIONS', 'SYSLIB_DEPS']
savedeps_files   = ['buildtools/wafsamba/samba_deps.py']

def save_samba_deps(bld, tgt_list):
    '''save the dependency calculations between builds, to make
       further builds faster'''
    denv = Environment.Environment()

    denv.version = savedeps_version
    denv.savedeps_inputs = savedeps_inputs
    denv.savedeps_outputs = savedeps_outputs
    denv.input = {}
    denv.output = {}
    denv.outenv = {}
    denv.caches = {}
    denv.envvar = {}
    denv.files  = {}

    for f in savedeps_files:
        denv.files[f] = os.stat(os.path.join(bld.srcnode.abspath(), f)).st_mtime

    for c in savedeps_caches:
        denv.caches[c] = LOCAL_CACHE(bld, c)

    for e in savedeps_envvars:
        denv.envvar[e] = bld.env[e]

    for t in tgt_list:
        # save all the input attributes for each target
        tdeps = {}
        for attr in savedeps_inputs:
            v = getattr(t, attr, None)
            if v is not None:
                tdeps[attr] = v
        if tdeps != {}:
            denv.input[t.sname] = tdeps

        # save all the output attributes for each target
        tdeps = {}
        for attr in savedeps_outputs:
            v = getattr(t, attr, None)
            if v is not None:
                tdeps[attr] = v
        if tdeps != {}:
            denv.output[t.sname] = tdeps

        tdeps = {}
        for attr in savedeps_outenv:
            if attr in t.env:
                tdeps[attr] = t.env[attr]
        if tdeps != {}:
            denv.outenv[t.sname] = tdeps

    depsfile = os.path.join(bld.bdir, "sambadeps")
    denv.store(depsfile)



def load_samba_deps(bld, tgt_list):
    '''load a previous set of build dependencies if possible'''
    depsfile = os.path.join(bld.bdir, "sambadeps")
    denv = Environment.Environment()
    try:
        debug('deps: checking saved dependencies')
        denv.load(depsfile)
        if (denv.version != savedeps_version or
            denv.savedeps_inputs != savedeps_inputs or
            denv.savedeps_outputs != savedeps_outputs):
            return False
    except:
        return False

    # check if critical files have changed
    for f in savedeps_files:
        if f not in denv.files:
            return False
        if denv.files[f] != os.stat(os.path.join(bld.srcnode.abspath(), f)).st_mtime:
            return False

    # check if caches are the same
    for c in savedeps_caches:
        if c not in denv.caches or denv.caches[c] != LOCAL_CACHE(bld, c):
            return False

    # check if caches are the same
    for e in savedeps_envvars:
        if e not in denv.envvar or denv.envvar[e] != bld.env[e]:
            return False

    # check inputs are the same
    for t in tgt_list:
        tdeps = {}
        for attr in savedeps_inputs:
            v = getattr(t, attr, None)
            if v is not None:
                tdeps[attr] = v
        if t.sname in denv.input:
            olddeps = denv.input[t.sname]
        else:
            olddeps = {}
        if tdeps != olddeps:
            #print '%s: \ntdeps=%s \nodeps=%s' % (t.sname, tdeps, olddeps)
            return False

    # put outputs in place
    for t in tgt_list:
        if not t.sname in denv.output: continue
        tdeps = denv.output[t.sname]
        for a in tdeps:
            setattr(t, a, tdeps[a])

    # put output env vars in place
    for t in tgt_list:
        if not t.sname in denv.outenv: continue
        tdeps = denv.outenv[t.sname]
        for a in tdeps:
            t.env[a] = tdeps[a]

    debug('deps: loaded saved dependencies')
    return True



def check_project_rules(bld):
    '''check the project rules - ensuring the targets are sane'''

    targets = LOCAL_CACHE(bld, 'TARGET_TYPE')
    loops = {}
    inc_loops = {}

    # build a list of task generators we are interested in
    tgt_list = []
    for tgt in targets:
        type = targets[tgt]
        if not type in ['SUBSYSTEM', 'MODULE', 'BINARY', 'LIBRARY', 'ASN1', 'PYTHON']:
            continue
        t = bld.name_to_obj(tgt, bld.env)
        if t is None:
            Logs.error("Target %s of type %s has no task generator" % (tgt, type))
            sys.exit(1)
        tgt_list.append(t)

    add_samba_attributes(bld, tgt_list)

    if load_samba_deps(bld, tgt_list):
        return

    Logs.info("Checking project rules ...")

    debug('deps: project rules checking started')

    expand_subsystem_deps(bld)
    build_direct_deps(bld, tgt_list)
    break_dependency_loops(bld, tgt_list)
    calculate_final_deps(bld, tgt_list, loops)

    # run the various attribute generators
    for f in [ build_dependencies, build_includes, add_init_functions ]:
        debug('deps: project rules checking %s', f)
        for t in tgt_list: f(t)

    debug('deps: project rules stage1 completed')

    #check_orpaned_targets(bld, tgt_list)

    if not check_duplicate_sources(bld, tgt_list):
        Logs.error("Duplicate sources present - aborting")
        sys.exit(1)

    if not check_group_ordering(bld, tgt_list):
        Logs.error("Bad group ordering - aborting")
        sys.exit(1)

    show_final_deps(bld, tgt_list)

    debug('deps: project rules checking completed - %u targets checked',
          len(tgt_list))

    save_samba_deps(bld, tgt_list)

    Logs.info("Project rules pass")


def CHECK_PROJECT_RULES(bld):
    '''enable checking of project targets for sanity'''
    if bld.env.added_project_rules:
        return
    bld.env.added_project_rules = True
    bld.add_pre_fun(check_project_rules)
Build.BuildContext.CHECK_PROJECT_RULES = CHECK_PROJECT_RULES