contrib: unused_functions.py: Handle archives

one can now use verbatim the arguments used by the driver invocation to
link e.g. cc1.

2018-10-04  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>

	* unused_functions.py: Handle archive files.

From-SVN: r264856

2 files changed, 101 insertions, 30 deletions

diff --git a/contrib/ChangeLog b/contrib/ChangeLog
index c1a68e6..498abb5 100644
--- a/contrib/ChangeLog
+++ b/contrib/ChangeLog
@@ -1,5 +1,9 @@
 2018-10-04  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>
 
+	* unused_functions.py: Handle archive files.
+
+2018-10-04  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>
+
 	* unused_functions.py: New file.
 
 2018-09-25  Martin Liska  <mliska@suse.cz>
diff --git a/contrib/unused_functions.py b/contrib/unused_functions.py
index 85b65c7..bf7cf36 100755
--- a/contrib/unused_functions.py
+++ b/contrib/unused_functions.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+# -*- coding: utf-8 -*-
 #
 # Copyright (c) 2018 Free Software Foundation
 # Contributed by Bernhard Reutner-Fischer <aldot@gcc.gnu.org>
@@ -17,71 +18,125 @@
 # unused_functions.py gcc/cp gcc/c-family/ gcc/*-c.o | grep -v "'gt_"
 
 import sys, os
+from tempfile import mkdtemp
+from subprocess import Popen, PIPE
 
 def usage():
-    sys.stderr.write("usage: %s [dirs | files] [-- <readelf options>]\n"
+    sys.stderr.write("usage: %s [-v] [dirs | files] [-- <readelf options>]\n"
                         % sys.argv[0])
+    sys.stderr.write("\t-v\tVerbose output\n");
     sys.exit(1)
 
-(odir, sym_args) = (set(), "")
+(odir, sym_args, tmpd, verbose) = (set(), "", None, False)
 
 for i in range(1, len(sys.argv)):
     f = sys.argv[i]
-    if f == "--": # sym_args
-        sym_args = " ".join(sys.argv[i + 1:])
+    if f == '--': # sym_args
+        sym_args = ' '.join(sys.argv[i + 1:])
         break
+    if f == '-v':
+        verbose = True
+        continue
     if not os.path.exists(f):
         sys.stderr.write("Error: No such file or directory '%s'\n" % f)
         usage()
     else:
+        if f.endswith('.a') and tmpd is None:
+            tmpd = mkdtemp(prefix='unused_fun')
         odir.add(f)
 
+def dbg(args):
+    if not verbose: return
+    print(args)
+
 def get_symbols(file):
     syms = {}
-    for l in os.popen("readelf -W -s %s %s | c++filt" % (sym_args, file)).readlines():
+    rargs = "readelf -W -s %s %s" % (sym_args, file)
+    p0 = Popen((a for a in rargs.split(' ') if a.strip() != ''), stdout=PIPE)
+    p1 = Popen(["c++filt"], stdin=p0.stdout, stdout=PIPE,
+            universal_newlines=True)
+    lines = p1.communicate()[0]
+    for l in lines.split('\n'):
         l = l.strip()
-        if not (len(l) and l[0].isdigit() and len(l.split()) == 8):
-            continue
-        num, value, size, typ, bind, vis, ndx, name = l.split()
+        if not len(l) or not l[0].isdigit(): continue
+        larr = l.split()
+        if len(larr) != 8: continue
+        num, value, size, typ, bind, vis, ndx, name = larr
         if typ == 'SECTION' or typ == 'FILE': continue
         # I don't think we have many aliases in gcc, re-instate the addr
         # lut otherwise.
-        if vis != "DEFAULT": continue
+        if vis != 'DEFAULT': continue
         #value = int(value, 16)
         #size = int(size, 16) if size.startswith('0x') else int(size)
-        defined = ndx != "UND"
-        globl = bind == "GLOBAL"
+        defined = ndx != 'UND'
+        globl = bind == 'GLOBAL'
         # c++ RID_FUNCTION_NAME dance. FORNOW: Handled as local use
         # Is that correct?
-        if name.endswith("::__FUNCTION__") and typ == "OBJECT":
-            name = name[0:(len(name) - len("::__FUNCTION__"))]
+        if name.endswith('::__FUNCTION__') and typ == 'OBJECT':
+            name = name[0:(len(name) - len('::__FUNCTION__'))]
             if defined: defined = False
         if defined and not globl: continue
         syms.setdefault(name, {})
-        syms[name][["use","def"][defined]] = True
-        syms[name][["local","global"][globl]] = True
+        syms[name][['use','def'][defined]] = True
+        syms[name][['local','global'][globl]] = True
     # Note: we could filter out e.g. debug_* symbols by looking for
     # value in the debug_macro sections.
+    if p1.returncode != 0:
+        print("Warning: Reading file '%s' exited with %r|%r"
+            % (file, p0.returncode, p1.returncode))
+    p0.kill()
     return syms
 
 (oprog, nprog) = ({}, {})
 
 def walker(paths):
+    def ar_x(archive):
+        dbg("Archive %s" % path)
+        f = os.path.abspath(archive)
+        f = os.path.splitdrive(f)[1]
+        d = tmpd + os.path.sep + f
+        d = os.path.normpath(d)
+        owd = os.getcwd()
+        try:
+            os.makedirs(d)
+            os.chdir(d)
+            p0 = Popen(["ar", "x", "%s" % os.path.join(owd, archive)],
+                    stderr=PIPE, universal_newlines=True)
+            p0.communicate()
+            if p0.returncode > 0: d = None # assume thin archive
+        except:
+            dbg("ar x: Error: %s: %s" % (archive, sys.exc_info()[0]))
+            os.chdir(owd)
+            raise
+        os.chdir(owd)
+        if d: dbg("Extracted to %s" % (d))
+        return (archive, d)
+
+    def ar_t(archive):
+        dbg("Thin archive, using existing files:")
+        try:
+            p0 = Popen(["ar", "t", "%s" % archive], stdout=PIPE,
+                    universal_newlines=True)
+            ret = p0.communicate()[0]
+            return ret.split('\n')
+        except:
+            dbg("ar t: Error: %s: %s" % (archive, sys.exc_info()[0]))
+            raise
+
     prog = {}
     for path in paths:
         if os.path.isdir(path):
             for r, dirs, files in os.walk(path):
-                for f in files:
-                    # TODO: maybe extract .a to a tmpdir and walk that, too
-                    # maybe /there/foolib.a(file.o) as name?
-                    if not f.endswith(".o"): continue
-                    p = os.path.join(r, f)
-                    prog[os.path.normpath(p)] = get_symbols(p)
-                for d in dirs:
-                    tem = prog.copy()
-                    tem.update(walker([os.path.join(r, d)]))
-                    prog = tem
+                if files: dbg("Files %s" % ", ".join(files))
+                if dirs: dbg("Dirs  %s" % ", ".join(dirs))
+                prog.update(walker([os.path.join(r, f) for f in files]))
+                prog.update(walker([os.path.join(r, d) for d in dirs]))
         else:
+            if path.endswith('.a'):
+                if ar_x(path)[1] is not None: continue # extract worked
+                prog.update(walker(ar_t(path)))
+            if not path.endswith('.o'): continue
+            dbg("Reading symbols from %s" % (path))
             prog[os.path.normpath(path)] = get_symbols(path)
     return prog
 
@@ -92,8 +147,8 @@ def resolve(prog):
     for (f, g) in ((f,g) for f in x for g in x if f != g):
         refs = set()
         # for each defined symbol
-        for s in (s for s in prog[f] if prog[f][s].get("def") and s in prog[g]):
-            if prog[g][s].get("use"):
+        for s in (s for s in prog[f] if prog[f][s].get('def') and s in prog[g]):
+            if prog[g][s].get('use'):
                 refs.add(s)
         for s in refs:
             # Prune externally referenced symbols as speed optimization only
@@ -101,10 +156,22 @@ def resolve(prog):
         use |= refs
     return use
 
-oprog = walker(odir)
-oused = resolve(oprog)
+try:
+    oprog = walker(odir)
+    if tmpd is not None:
+        oprog.update(walker([tmpd]))
+    oused = resolve(oprog)
+finally:
+    try:
+        p0 = Popen(["rm", "-r", "-f", "%s" % (tmpd)], stderr=PIPE, stdout=PIPE)
+        p0.communicate()
+        if p0.returncode != 0: raise "rm '%s' didn't work out" % (tmpd)
+    except:
+        from shutil import rmtree
+        rmtree(tmpd, ignore_errors=True)
+
 for (i,s) in ((i,s) for i in oprog.keys() for s in oprog[i] if oprog[i][s]):
-    if oprog[i][s].get("def") and not oprog[i][s].get("use"):
+    if oprog[i][s].get('def') and not oprog[i][s].get('use'):
         print("%s: Symbol '%s' declared extern but never referenced externally"
             % (i,s))