initial checkin - perl script which finds unused or little used exports from a dll

tools/module-deps/find-unused-exports.pl

@@ -0,0 +1,139 @@
+#!/bin/env perl
+
+my $export_file;
+my @import_files;
+
+# first argument is the file that's exporting
+# all further arguments are the input files
+
+foreach $arg (@ARGV) {
+  if (!$export_file) {
+    $export_file = $arg;
+  } else {
+    push @import_files, $arg;
+  }
+}
+
+open EXPORTS, "dumpbin /exports $export_file|";
+
+my %exports;
+
+my $found_exports;
+while (<EXPORTS>) {
+  # format is
+  # ordinal hint RVA? name
+  if ($found_exports) {
+    # break up the words
+    my @words = split /\s+/;
+    next if ($#words != 4);
+
+    my $ordinal = $words[1];
+    my $name = $words[4];
+
+    $exports{$name} = 0;
+    
+  } elsif (/ordinal\s+hint\s+RVA/) {
+    $found_exports = 1;
+  }
+}
+
+close EXPORTS;
+
+#
+# now read in all imports, and ++ the imports from the exported file
+#
+foreach $filename (@import_files) {
+
+  print STDERR "gathering data for $filename\n";
+  open IMPORTS, "dumpbin /imports $filename|";
+  my $current_import_dll, $awaiting_import_dll, $importing_from;
+  while (<IMPORTS>) {
+    chop;
+    if (/Dump of file ([^\s]+)/) {
+      $awaiting_import_dll = 0;
+      $current_import_dll = $1;
+      #print STDERR "Found imports for $current_import_dll\n";
+
+    } elsif (/Section contains the following imports/) {
+      $awaiting_import_dll = 1;
+
+    } elsif ($awaiting_import_dll && /^\s+([\w\.]+)$/) {
+      $importing_from = $1;
+      $awaiting_import_dll = 0;
+      $awaiting_import_header = 1;
+      # print STDERR "$current_import_dll: Importing from $importing_from\n";
+    } elsif ($awaiting_import_header) {
+      if ($_ eq "") {
+        $awaiting_import_header = 0;
+      }
+      # print STDERR "...Skipped past header, starting imports\n" if (!$awaiting_import_header);
+
+    } else {
+      if ($_ eq "") {
+        $awaiting_import_dll = 1;
+        next;
+      }
+      if ($export_file eq $importing_from) {
+        # must be an import line
+        @imports = split /\s+/;
+        next if ($#imports != 2);
+        my $name = $imports[2];
+        #print STDERR "... importing $name from $export_file\n";
+        $exports{$name}++;
+        $last_consumer_of{$name} = $current_import_dll;
+
+        #      print STDERR "Got import $importing_from\[$imports[2]\]\n";
+      }
+    }
+  }
+  close IMPORTS;
+}
+
+print STDERR "finding infrequently imported symbols..\n";
+foreach $func (sort keys %exports) {
+  if ($exports{$func} < 2) {
+    push @funcs_to_demangle, $func;
+  } else {
+    #print STDERR "Found $exports{$func} consumers of $func\n";
+  }
+}
+
+print STDERR "Demangling..$#funcs_to_demangle unused symbols\n";
+
+my $max_per_run = 20;
+
+while ($func = pop @funcs_to_demangle) {
+  $count++;
+  $funcs_to_demangle .= " $func";
+  
+  if ($count == $max_per_run || ($#funcs_to_demangle == 0)) {
+    # set up the initial slot where the demangled name goes
+    open UNDNAME, "undname -f $funcs_to_demangle|";
+    while (<UNDNAME>) {
+      chop;
+
+      #      print STDERR "Got result $_\n";
+      if (/\s*(\S+)\s*==\s*(.*)$/) {
+        #        print STDERR"succesfully demangled $1 to $2\n";
+        $demangle{$1} = $2;
+      } else {
+        $demangle{$1} = $1;
+      }
+    }
+    close UNDNAME;
+    $funcs_to_demangle = "";
+    $count = 0;
+  }
+}
+
+print STDERR "Done.\n";
+
+foreach $func (sort keys %demangle ) {
+
+  next if ($demangle{$func} =~ /vftable/);
+  if ($exports{$func} == 0) {
+    print "$demangle{$func}: No importers\n";
+  } elsif ($exports{$func} == 1) {
+    print "$demangle{$func}: One consumer: $last_consumer_of{$func}\n";
+  }
+}