dgcov: import, rewrite to work with cmake and git

.gitignore

@@ -3,6 +3,7 @@
 *.reject
 *.spec
 *.bak
+*.dgcov
 *.rpm
 .*.swp
 *.ninja

mysql-test/dgcov.pl

+#! /usr/bin/perl
+
+# Copyright (C) 2003,2008 MySQL AB
+# Copyright (C) 2010,2017 Sergei Golubchik and MariaDB Corporation
+#
+# 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; version 2 of the License.
+#
+# 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
+
+# Run gcov and report test coverage on only those code lines touched by
+# a given list of commits.
+
+use strict;
+use warnings;
+
+use Getopt::Long;
+use File::Find;
+use Cwd qw/realpath/;
+
+my $opt_verbose=0;
+my $opt_generate;
+my $opt_help;
+my $opt_purge;
+my $opt_only_gcov;
+my $opt_skip_gcov;
+
+my %cov;
+my $file_no=0;
+
+GetOptions
+  ("v|verbose+"    => \$opt_verbose,
+   "h|help"        => \$opt_help,
+   "p|purge"       => \$opt_purge,
+   "g|generate"    => \$opt_generate,
+   "o|only-gcov"   => \$opt_only_gcov,
+   "s|skip-gcov"   => \$opt_skip_gcov,
+  ) or usage();
+
+usage() if $opt_help;
+
+sub logv(@)     { print STDERR @_,"\n" if $opt_verbose; }
+sub gcov_prefix($) { defined($_[0]) ? $_[0] || '#####' : '-' }
+
+my $root= `git rev-parse --show-toplevel`;
+chomp $root;
+
+die "Failed to find tree root" unless $root;
+$root=realpath($root).'/';
+logv "Chdir $root";
+chdir $root or die "chdir($root): $!";
+
+my $res;
+my $cmd;
+if ($opt_purge)
+{
+  $cmd= "find . -name '*.da' -o -name '*.gcda' -o -name '*.gcov' -o ".
+               "-name '*.dgcov' | grep -v 'README\.gcov' | xargs rm -f ''";
+  logv "Running: $cmd";
+  system($cmd)==0 or die "system($cmd): $? $!";
+  exit 0;
+}
+
+find(\&gcov_one_file, $root);
+find(\&write_coverage, $root) if $opt_generate;
+exit 0 if $opt_only_gcov;
+
+if (@ARGV) {
+  print_gcov_for_diff(@ARGV);
+} else {
+  print_gcov_for_diff('HEAD') or print_gcov_for_diff('HEAD^');
+}
+exit 0;
+
+sub print_gcov_for_diff {
+  $cmd="git diff --no-prefix --ignore-space-change @_";
+  logv "Running: $cmd";
+  open PIPE, '-|', $cmd or die "Failed to popen '$cmd': $!: $?";
+  my ($lnum, $cnt, $fcov, $acc, $printme, $fname);
+  while (<PIPE>) {
+    if (/^diff --git (.*) \1\n/) {
+      print $acc if $printme;
+      $fname=$1;
+      $acc="dgcov $fname";
+      $acc=('*' x length($acc)) . "\n$acc\n" . ('*' x length($acc));
+      $lnum=undef;
+      $fcov=$cov{realpath($fname)};
+      $printme=0;
+      logv "File: $fname";
+      next;
+    }
+    if (/^@@ -\d+,\d+ \+(\d+),(\d+) @@/ and $fcov) {
+      $lnum=$1;
+      $cnt=$2;
+      $acc.="\n@@ +$lnum,$cnt @\@$'";
+      logv "  lines: $lnum,",$lnum+$cnt;
+      next;
+    }
+    next unless $lnum and $cnt;
+    $acc.=sprintf '%9s:%5s:%s', '', $lnum, $' if /^ /;
+    ++$printme, $acc.=sprintf '%9s:%5s:%s', gcov_prefix($fcov->{$lnum}), $lnum, $' if /^\+/;
+    die "$_^^^ dying", unless /^[- +]/;
+    ++$lnum;
+    --$cnt;
+  }
+  print $acc if $printme;
+  close PIPE or die "command '$cmd' failed: $!: $?";
+  return defined($fname);
+}
+
+sub usage {
+  print <<END;
+Usage: $0 --help
+       $0 [options] [git diff arguments]
+
+The dgcov program runs gcov for code coverage analysis, and reports missing
+coverage only for those lines that are changed by the specified commit(s).
+Commits are specified in the format of git diff arguments. For example:
+ * All unpushed commits:        $0 \@{u} HEAD
+ * All uncommitted changes:     $0 HEAD
+ * Specific commit:             $0 <commit>^ <commit>
+
+If no arguments are specified, it prints the coverage for all uncommitted
+changes, if any, otherwise for the last commit.
+
+Options:
+
+  -h    --help        This help.
+  -v    --verbose     Show commands run.
+  -p    --purge       Delete all test coverage information, to prepare for a
+                      new coverage test.
+  -o    --only-gcov   Stop after running gcov, don't run git
+  -s    --skip-gcov   Do not run gcov, assume .gcov files are already in place
+  -g    --generate    Create .dgcov files for all source files
+
+Prior to running this tool, MariaDB should be built with
+
+  cmake -DENABLE_GCOV=ON
+
+and the testsuite should be run. dgcov will report the coverage
+for all lines modified in the specified commits.
+END
+
+  exit 1;
+}
+
+sub gcov_one_file {
+  return unless /\.gcda$/;
+  unless ($opt_skip_gcov) {
+    $cmd= "gcov -i '$_' 2>/dev/null >/dev/null";
+    print STDERR ++$file_no,"\r" if not $opt_verbose and -t STDERR;
+    logv "Running: $cmd";
+    system($cmd)==0 or die "system($cmd): $? $!";
+  }
+
+  # now, read the generated file
+  open FH, '<', "$_.gcov" or die "open(<$_.gcov): $!";
+  my $fname;
+  while (<FH>) {
+    chomp;
+    if (/^function:/) {
+      next;
+    }
+    if (/^file:/) {
+      $fname=realpath($');
+      next;
+    }
+    next if /^lcount:\d+,-\d+/; # whatever that means
+    unless (/^lcount:(\d+),(\d+)/ and $fname) {
+      warn "unknown line '$_' after running '$cmd'";
+      next;
+    }
+    $cov{$fname}->{$1}+=$2;
+  }
+  close(FH);
+}
+
+sub write_coverage {
+  my $fn=$File::Find::name;
+  my $h=$cov{$fn};
+  return unless $h and $root eq substr $fn, 0, length($root);
+  open I, '<', $fn or die "open(<$fn): $!";
+  open O, '>', "$fn.dgcov" or die "open(>$fn.dgcov): $!";
+  logv "Annotating: ", substr $fn, length($root);
+  while (<I>) {
+    printf O '%9s:%5s:%s', gcov_prefix($h->{$.}), $., $_;
+  }
+  close I;
+  close O;
+}