Add support for mklibs (strips unused syms from shared libs such as uClibc)

based on a patch from akvadrako, and using a version of mklibs.py that was
massively hacked up by andersee and mjn3 for uClibc support.

1 files changed, 597 insertions, 0 deletions

diff --git a/toolchain/mklibs/mklibs.py b/toolchain/mklibs/mklibs.py
new file mode 100644
index 000000000..a84fd42fa
--- /dev/null
+++ b/toolchain/mklibs/mklibs.py
@@ -0,0 +1,597 @@
+#! /usr/bin/python
+
+# mklibs.py: An automated way to create a minimal /lib/ directory.
+#
+# Copyright 2001 by Falk Hueffner <falk@debian.org>
+#                 & Goswin Brederlow <goswin.brederlow@student.uni-tuebingen.de>
+#
+# mklibs.sh by Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de>
+# used as template
+#
+#   This program is free software; you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation; either version 2 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program; if not, write to the Free Software
+#   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+# HOW IT WORKS
+#
+# - Gather all unresolved symbols and libraries needed by the programs
+#   and reduced libraries
+# - Gather all symbols provided by the already reduced libraries
+#   (none on the first pass)
+# - If all symbols are provided we are done
+# - go through all libraries and remember what symbols they provide
+# - go through all unresolved/needed symbols and mark them as used
+# - for each library:
+#   - find pic file (if not present copy and strip the so)
+#   - compile in only used symbols
+#   - strip
+# - back to the top
+
+# TODO
+# * complete argument parsing as given as comment in main
+
+import commands
+import string
+import re
+import sys
+import os
+import glob
+import getopt
+from stat import *
+
+DEBUG_NORMAL  = 1
+DEBUG_VERBOSE = 2
+DEBUG_SPAM    = 3
+
+debuglevel = DEBUG_NORMAL
+
+def debug(level, *msg):
+    if debuglevel >= level:
+        print string.join(msg)
+
+# A simple set class. It should be replaced with the standard sets.Set
+# type as soon as Python 2.3 is out.
+class Set:
+    def __init__(self):
+        self.__dict = {}
+
+    def add(self, obj):
+        self.__dict[obj] = 1
+
+    def contains(self, obj):
+        return self.__dict.has_key(obj)
+
+    def merge(self, s):
+        for e in s.elems():
+            self.add(e)
+
+    def elems(self):
+        return self.__dict.keys()
+
+    def size(self):
+        return len(self.__dict)
+
+    def __eq__(self, other):
+        return self.__dict == other.__dict
+
+    def __str__(self):
+        return `self.__dict.keys()`
+
+    def __repr__(self):
+        return `self.__dict.keys()`
+
+# return a list of lines of output of the command
+def command(command, *args):
+    debug(DEBUG_SPAM, "calling", command, string.join(args))
+    (status, output) = commands.getstatusoutput(command + ' ' + string.join(args))
+    if os.WEXITSTATUS(status) != 0:
+        print "Command failed with status", os.WEXITSTATUS(status),  ":", \
+               command, string.join(args)
+	print "With output:", output
+        sys.exit(1)
+    return string.split(output, '\n')
+
+# Filter a list according to a regexp containing a () group. Return
+# a Set.
+def regexpfilter(list, regexp, groupnr = 1):
+    pattern = re.compile(regexp)
+    result = Set()
+    for x in list:
+        match = pattern.match(x)
+        if match:
+            result.add(match.group(groupnr))
+
+    return result
+
+# Return a Set of rpath strings for the passed object
+def rpath(obj):
+    if not os.access(obj, os.F_OK):
+        raise "Cannot find lib: " + obj
+    output = command(target + "objdump", "--private-headers", obj)
+    return map(lambda x: root + "/" + x, regexpfilter(output, ".*RPATH\s*(\S+)$").elems())
+
+# Return a Set of libraries the passed objects depend on.
+def library_depends(obj):
+    if not os.access(obj, os.F_OK):
+        raise "Cannot find lib: " + obj
+    output = command(target + "objdump", "--private-headers", obj)
+    return regexpfilter(output, ".*NEEDED\s*(\S+)$")
+
+# Return a list of libraries the passed objects depend on. The
+# libraries are in "-lfoo" format suitable for passing to gcc.
+def library_depends_gcc_libnames(obj):
+    if not os.access(obj, os.F_OK):
+        raise "Cannot find lib: " + obj
+    output = command(target + "objdump", "--private-headers", obj)
+    output = regexpfilter(output, ".*NEEDED\s*lib(\S+)\.so.*$")
+    if not output.elems():
+        return ""
+    else:
+        return "-l" + string.join(output.elems(), " -l")
+
+# Scan readelf output. Example:
+# Num:    Value          Size Type    Bind   Vis      Ndx Name
+#   1: 000000012002ab48   168 FUNC    GLOBAL DEFAULT  UND strchr@GLIBC_2.0 (2)
+symline_regexp = \
+    re.compile("\s*\d+: .+\s+\d+\s+\w+\s+(\w+)+\s+\w+\s+(\w+)\s+([^\s@]+)")
+
+# Return undefined symbols in an object as a Set of tuples (name, weakness)
+def undefined_symbols(obj):
+    if not os.access(obj, os.F_OK):
+        raise "Cannot find lib" + obj
+
+    result = Set()
+    output = command(target + "readelf", "-s", "-W", obj)
+    for line in output:
+        match = symline_regexp.match(line)
+        if match:
+            bind, ndx, name = match.groups()
+            if ndx == "UND":
+                result.add((name, bind == "WEAK"))
+    return result
+
+# Return a Set of symbols provided by a library
+def provided_symbols(obj):
+    if not os.access(obj, os.F_OK):
+        raise "Cannot find lib" + obj
+
+    result = Set()
+    debug(DEBUG_SPAM, "provided_symbols result = ", `result`)
+    output = command(target + "readelf", "-s", "-W", obj)
+    for line in output:
+        match = symline_regexp.match(line)
+        if match:
+            bind, ndx, name = match.groups()
+            if bind != "LOCAL" and not ndx in ("UND", "ABS"):
+                debug(DEBUG_SPAM, "provided_symbols adding ", `name`)
+                result.add(name)
+    return result
+
+# Return real target of a symlink
+def resolve_link(file):
+    debug(DEBUG_SPAM, "resolving", file)
+    while S_ISLNK(os.lstat(file)[ST_MODE]):
+        new_file = os.readlink(file)
+        if new_file[0] != "/":
+            file = os.path.join(os.path.dirname(file), new_file)
+        else:
+            file = new_file
+    debug(DEBUG_SPAM, "resolved to", file)
+    return file
+
+# Find complete path of a library, by searching in lib_path
+def find_lib(lib):
+    for path in lib_path:
+        if os.access(path + "/" + lib, os.F_OK):
+            return path + "/" + lib
+
+    return ""
+
+# Find a PIC archive for the library
+def find_pic(lib):
+    base_name = so_pattern.match(lib).group(1)
+    for path in lib_path:
+        for file in glob.glob(path + "/" + base_name + "_pic.a"):
+            if os.access(file, os.F_OK):
+                return resolve_link(file)
+    return ""
+
+# Find a PIC .map file for the library
+def find_pic_map(lib):
+    base_name = so_pattern.match(lib).group(1)
+    for path in lib_path:
+        for file in glob.glob(path + "/" + base_name + "_pic.map"):
+            if os.access(file, os.F_OK):
+                return resolve_link(file)
+    return ""
+
+def extract_soname(so_file):
+    soname_data = regexpfilter(command(target + "readelf", "--all", "-W", so_file),
+                               ".*SONAME.*\[(.*)\].*")
+    if soname_data.elems():
+        return soname_data.elems()[0]
+
+    return ""
+def usage(was_err):
+    if was_err:
+        outfd = sys.stderr
+    else:
+        outfd = sys.stdout
+    print >> outfd, "Usage: mklibs [OPTION]... -d DEST FILE ..."
+    print >> outfd, "Make a set of minimal libraries for FILE(s) in DEST."
+    print >> outfd, ""
+    print >> outfd, "  -d, --dest-dir DIRECTORY     create libraries in DIRECTORY"
+    print >> outfd, "  -D, --no-default-lib         omit default libpath (", string.join(default_lib_path, " : "), ")"
+    print >> outfd, "  -L DIRECTORY[:DIRECTORY]...  add DIRECTORY(s) to the library search path"
+    print >> outfd, "      --ldlib LDLIB            use LDLIB for the dynamic linker"
+    print >> outfd, "      --libc-extras-dir DIRECTORY  look for libc extra files in DIRECTORY"
+    # Ugh... Adding the trailing '-' breaks common practice.
+    #print >> outfd, "      --target TARGET          prepend TARGET- to the gcc and binutils calls"
+    print >> outfd, "      --target TARGET          prepend TARGET to the gcc and binutils calls"
+    print >> outfd, "      --root ROOT              search in ROOT for library rpaths"
+    print >> outfd, "  -v, --verbose                explain what is being done"
+    print >> outfd, "  -h, --help                   display this help and exit"
+    sys.exit(was_err)
+
+def version(vers):
+    print "mklibs: version ",vers
+    print ""
+
+#################### main ####################
+## Usage: ./mklibs.py [OPTION]... -d DEST FILE ...
+## Make a set of minimal libraries for FILE ... in directory DEST.
+##
+## Options:
+##   -L DIRECTORY               Add DIRECTORY to library search path.
+##   -D, --no-default-lib       Do not use default lib directories of /lib:/usr/lib
+##   -n, --dry-run              Don't actually run any commands; just print them.
+##   -v, --verbose              Print additional progress information.
+##   -V, --version              Print the version number and exit.
+##   -h, --help                 Print this help and exit.
+##   --ldlib                    Name of dynamic linker (overwrites environment variable ldlib)
+##   --libc-extras-dir          Directory for libc extra files
+##   --target                   Use as prefix for gcc or binutils calls
+##
+##   -d, --dest-dir DIRECTORY   Create libraries in DIRECTORY.
+##
+## Required arguments for long options are also mandatory for the short options.
+
+# Clean the environment
+vers="0.12 with uClibc fixes"
+os.environ['LC_ALL'] = "C"
+
+# Argument parsing
+opts = "L:DnvVhd:r:"
+longopts = ["no-default-lib", "dry-run", "verbose", "version", "help",
+            "dest-dir=", "ldlib=", "libc-extras-dir=", "target=", "root="]
+
+# some global variables
+lib_rpath = []
+lib_path = []
+dest_path = "DEST"
+ldlib = "LDLIB"
+include_default_lib_path = "yes"
+default_lib_path = ["/lib/", "/usr/lib/", "/usr/X11R6/lib/"]
+libc_extras_dir = "/usr/lib/libc_pic"
+target = ""
+root = ""
+so_pattern = re.compile("((lib|ld).*)\.so(\..+)*")
+script_pattern = re.compile("^#!\s*/")
+
+try:
+    optlist, proglist = getopt.getopt(sys.argv[1:], opts, longopts)
+except getopt.GetoptError, msg:
+    print >> sys.stderr, msg
+    usage(1)
+
+for opt, arg in optlist:
+    if opt in ("-v", "--verbose"):
+        if debuglevel < DEBUG_SPAM:
+            debuglevel = debuglevel + 1
+    elif opt == "-L":
+        lib_path.extend(string.split(arg, ":"))
+    elif opt in ("-d", "--dest-dir"):
+        dest_path = arg
+    elif opt in ("-D", "--no-default-lib"):
+        include_default_lib_path = "no"
+    elif opt == "--ldlib":
+        ldlib = arg
+    elif opt == "--libc-extras-dir":
+        libc_extras_dir = arg
+    elif opt == "--target":
+        #target = arg + "-"
+        target = arg
+    elif opt in ("-r", "--root"):
+        root = arg
+    elif opt in ("--help", "-h"):
+	usage(0)
+        sys.exit(0)
+    elif opt in ("--version", "-V"):
+        version(vers)
+        sys.exit(0)
+    else:
+        print "WARNING: unknown option: " + opt + "\targ: " + arg
+
+if include_default_lib_path == "yes":
+    lib_path.extend(default_lib_path)
+
+if ldlib == "LDLIB":
+    ldlib = os.getenv("ldlib")
+
+objects = {}  # map from inode to filename
+for prog in proglist:
+    inode = os.stat(prog)[ST_INO]
+    if objects.has_key(inode):
+        debug(DEBUG_SPAM, prog, "is a hardlink to", objects[inode])
+    elif so_pattern.match(prog):
+        debug(DEBUG_SPAM, prog, "is a library")
+    elif script_pattern.match(open(prog).read(256)):
+        debug(DEBUG_SPAM, prog, "is a script")
+    else:
+        objects[inode] = prog
+
+if not ldlib:
+    pattern = re.compile(".*Requesting program interpreter:.*/([^\]/]+).*")
+    for obj in objects.values():
+        output = command(target + "readelf", "--program-headers", obj)
+	for x in output:
+	    match = pattern.match(x)
+	    if match:
+	        ldlib = match.group(1)
+	        break
+	if ldlib:
+	    break
+
+if not ldlib:
+    sys.exit("E: Dynamic linker not found, aborting.")
+
+debug(DEBUG_NORMAL, "I: Using", ldlib, "as dynamic linker.")
+
+pattern = re.compile(".*ld-uClibc.*");
+if pattern.match(ldlib):
+    uclibc = 1
+else:
+    uclibc = 0
+
+# Check for rpaths
+for obj in objects.values():
+    rpath_val = rpath(obj)
+    if rpath_val:
+        if root:
+            if debuglevel >= DEBUG_VERBOSE:
+                print "Adding rpath " + string.join(rpath_val, ":") + " for " + obj
+            lib_rpath.extend(rpath_val)
+        else:
+            print "warning: " + obj + " may need rpath, but --root not specified"
+
+lib_path.extend(lib_rpath)
+
+passnr = 1
+previous_pass_unresolved = Set()
+while 1:
+    debug(DEBUG_NORMAL, "I: library reduction pass", `passnr`)
+    if debuglevel >= DEBUG_VERBOSE:
+        print "Objects:",
+        for obj in objects.values():
+            print obj[string.rfind(obj, '/') + 1:],
+        print
+
+    passnr = passnr + 1
+    # Gather all already reduced libraries and treat them as objects as well
+    small_libs = []
+    for lib in regexpfilter(os.listdir(dest_path), "(.*-so-stripped)$").elems():
+        obj = dest_path + "/" + lib
+        small_libs.append(obj)
+        inode = os.stat(obj)[ST_INO]
+        if objects.has_key(inode):
+            debug(DEBUG_SPAM, obj, "is hardlink to", objects[inode])
+        else:
+            objects[inode] = obj
+
+    # DEBUG
+    for obj in objects.values():
+        small_libs.append(obj)
+        debug(DEBUG_VERBOSE, "Object:", obj)
+
+    # calculate what symbols and libraries are needed
+    needed_symbols = Set()              # Set of (name, weakness-flag)
+    libraries = Set()
+    for obj in objects.values():
+        needed_symbols.merge(undefined_symbols(obj))
+        libraries.merge(library_depends(obj))
+
+    # FIXME: on i386 this is undefined but not marked UND
+    # I don't know how to detect those symbols but this seems
+    # to be the only one and including it on alpha as well
+    # doesn't hurt. I guess all archs can live with this.
+    needed_symbols.add(("sys_siglist", 1))
+
+    # calculate what symbols are present in small_libs
+    present_symbols = Set()
+    for lib in small_libs:
+        present_symbols.merge(provided_symbols(lib))
+
+    # are we finished?
+    using_ctor_dtor = 0
+    num_unresolved = 0
+    present_symbols_elems = present_symbols.elems()
+    unresolved = Set()
+    for (symbol, is_weak) in needed_symbols.elems():
+        if not symbol in present_symbols_elems:
+            debug(DEBUG_SPAM, "Still need:", symbol, `is_weak`)
+            unresolved.add((symbol, is_weak))
+            num_unresolved = num_unresolved + 1
+
+    debug (DEBUG_NORMAL, `needed_symbols.size()`, "symbols,",
+           `num_unresolved`, "unresolved")
+
+    if num_unresolved == 0:
+        break
+
+    if unresolved == previous_pass_unresolved:
+        # No progress in last pass. Verify all remaining symbols are weak.
+        for (symbol, is_weak) in unresolved.elems():
+            if not is_weak:
+                raise "Unresolvable symbol " + symbol
+        break
+
+    previous_pass_unresolved = unresolved
+
+    library_symbols = {}
+    library_symbols_used = {}
+    symbol_provider = {}
+
+    # Calculate all symbols each library provides
+    for library in libraries.elems():
+        path = find_lib(library)
+        if not path:
+            sys.exit("Library not found: " + library + " in path: "
+                     + string.join(lib_path, " : "))
+        symbols = provided_symbols(path)
+        library_symbols[library] = Set()
+        library_symbols_used[library] = Set()
+        for symbol in symbols.elems():
+            if symbol_provider.has_key(symbol):
+                # in doubt, prefer symbols from libc
+                if re.match("^libc[\.-]", library):
+                    library_symbols[library].add(symbol)
+                    symbol_provider[symbol] = library
+                else:
+                    debug(DEBUG_SPAM, "duplicate symbol", symbol, "in",
+                          symbol_provider[symbol], "and", library)
+            else:
+                library_symbols[library].add(symbol)
+                symbol_provider[symbol] = library
+
+	# Fixup support for constructors and destructors
+	if symbol_provider.has_key("_init"):
+	    debug(DEBUG_VERBOSE, library, ": Library has a constructor!");
+	    using_ctor_dtor = 1
+	    library_symbols[library].add("_init")
+	    symbol_provider["_init"] = library
+            library_symbols_used[library].add("_init")
+
+	if symbol_provider.has_key("_fini"):
+	    debug(DEBUG_VERBOSE, library, ": Library has a destructor!");
+	    using_ctor_dtor = 1
+	    library_symbols[library].add("_fini")
+	    symbol_provider["_fini"] = library
+            library_symbols_used[library].add("_fini")
+
+    # which symbols are actually used from each lib
+    for (symbol, is_weak) in needed_symbols.elems():
+        if not symbol_provider.has_key(symbol):
+            if not is_weak:
+                if not uclibc or (symbol != "main"):
+                    raise "No library provides non-weak " + symbol
+        else:
+            lib = symbol_provider[symbol]
+            library_symbols_used[lib].add(symbol)
+
+    # reduce libraries
+    for library in libraries.elems():
+        debug(DEBUG_VERBOSE, "reducing", library)
+        debug(DEBUG_SPAM, "using: " + string.join(library_symbols_used[library].elems()))
+        so_file = find_lib(library)
+        if root and (re.compile("^" + root).search(so_file)):
+            debug(DEBUG_VERBOSE, "no action required for " + so_file)
+            continue
+        so_file_name = os.path.basename(so_file)
+        if not so_file:
+            sys.exit("File not found:" + library)
+        pic_file = find_pic(library)
+        if not pic_file:
+            # No pic file, so we have to use the .so file, no reduction
+            debug(DEBUG_VERBOSE, "No pic file found for", so_file, "; copying")
+            command(target + "objcopy", "--strip-unneeded -R .note -R .comment",
+                    so_file, dest_path + "/" + so_file_name + "-so-stripped")
+        else:
+            # we have a pic file, recompile
+            debug(DEBUG_SPAM, "extracting from:", pic_file, "so_file:", so_file)
+            soname = extract_soname(so_file)
+            if soname == "":
+                debug(DEBUG_VERBOSE, so_file, " has no soname, copying")
+                continue
+            debug(DEBUG_SPAM, "soname:", soname)
+            base_name = so_pattern.match(library).group(1)
+            # libc needs its soinit.o and sofini.o as well as the pic
+            if (base_name == "libc") and not uclibc:
+                # force dso_handle.os to be included, otherwise reduced libc
+                # may segfault in ptmalloc_init due to undefined weak reference
+                extra_flags = find_lib(ldlib) + " -u __dso_handle"
+                extra_pre_obj = libc_extras_dir + "/soinit.o"
+                extra_post_obj = libc_extras_dir + "/sofini.o"
+            else:
+                extra_flags = ""
+                extra_pre_obj = ""
+                extra_post_obj = ""
+            map_file = find_pic_map(library)
+            if map_file:
+                extra_flags = extra_flags + " -Wl,--version-script=" + map_file
+            if library_symbols_used[library].elems():
+                joined_symbols = "-u" + string.join(library_symbols_used[library].elems(), " -u")
+            else:
+                joined_symbols = ""
+	    if using_ctor_dtor == 1:
+                extra_flags = extra_flags + " -shared"
+            # compile in only used symbols
+            command(target + "gcc",
+                "-nostdlib -nostartfiles -shared -Wl,-soname=" + soname,\
+                joined_symbols, \
+                "-o", dest_path + "/" + so_file_name + "-so", \
+                extra_pre_obj, \
+                pic_file, \
+                extra_post_obj, \
+                extra_flags, \
+                "-lgcc -L", dest_path, \
+                "-L" + string.join(lib_path, " -L"), \
+                library_depends_gcc_libnames(so_file))
+            # strip result
+            command(target + "objcopy", "--strip-unneeded -R .note -R .comment",
+                      dest_path + "/" + so_file_name + "-so",
+                      dest_path + "/" + so_file_name + "-so-stripped")
+            ## DEBUG
+            debug(DEBUG_VERBOSE, so_file, "\t", `os.stat(so_file)[ST_SIZE]`)
+            debug(DEBUG_VERBOSE, dest_path + "/" + so_file_name + "-so", "\t",
+                  `os.stat(dest_path + "/" + so_file_name + "-so")[ST_SIZE]`)
+            debug(DEBUG_VERBOSE, dest_path + "/" + so_file_name + "-so-stripped",
+                  "\t", `os.stat(dest_path + "/" + so_file_name + "-so-stripped")[ST_SIZE]`)
+
+# Finalising libs and cleaning up
+for lib in regexpfilter(os.listdir(dest_path), "(.*)-so-stripped$").elems():
+    os.rename(dest_path + "/" + lib + "-so-stripped", dest_path + "/" + lib)
+for lib in regexpfilter(os.listdir(dest_path), "(.*-so)$").elems():
+    os.remove(dest_path + "/" + lib)
+
+# Canonicalize library names.
+for lib in regexpfilter(os.listdir(dest_path), "(.*so[.\d]*)$").elems():
+    this_lib_path = dest_path + "/" + lib
+    if os.path.islink(this_lib_path):
+        debug(DEBUG_VERBOSE, "Unlinking %s." % lib)
+        os.remove(this_lib_path)
+        continue
+    soname = extract_soname(this_lib_path)
+    if soname:
+        debug(DEBUG_VERBOSE, "Moving %s to %s." % (lib, soname))
+        os.rename(dest_path + "/" + lib, dest_path + "/" + soname)
+
+# Make sure the dynamic linker is present and is executable
+ld_file = find_lib(ldlib)
+ld_file_name = os.path.basename(ld_file)
+
+if not os.access(dest_path + "/" + ld_file_name, os.F_OK):
+    debug(DEBUG_NORMAL, "I: stripping and copying dynamic linker.")
+    command(target + "objcopy", "--strip-unneeded -R .note -R .comment",
+            ld_file, dest_path + "/" + ld_file_name)
+
+os.chmod(dest_path + "/" + ld_file_name, 0755)