bin/scan-build

#!/usr/bin/env perl
#
#                     The LLVM Compiler Infrastructure
#
# This file is distributed under the University of Illinois Open Source
# License. See LICENSE.TXT for details.
#
##===----------------------------------------------------------------------===##
#
# A script designed to wrap a build so that all calls to gcc are intercepted
# and piped to the static analyzer.
#
##===----------------------------------------------------------------------===##

use strict;
use warnings;
use FindBin qw($RealBin);
use Digest::MD5;
use File::Basename;
use File::Find;
use File::Copy qw(copy);
use File::Path qw( rmtree mkpath );
use Term::ANSIColor;
use Term::ANSIColor qw(:constants);
use Cwd qw/ getcwd abs_path /;
use Sys::Hostname;

my $Verbose = 0;       # Verbose output from this script.
my $Prog = "scan-build";
my $BuildName;
my $BuildDate;

my $TERM = $ENV{'TERM'};
my $UseColor = (defined $TERM and $TERM =~ 'xterm-.*color' and -t STDOUT
                and defined $ENV{'SCAN_BUILD_COLOR'});

# Portability: getpwuid is not implemented for Win32 (see Perl language
# reference, perlport), use getlogin instead.
my $UserName = HtmlEscape(getlogin() || getpwuid($<) || 'unknown');
my $HostName = HtmlEscape(hostname() || 'unknown');
my $CurrentDir = HtmlEscape(getcwd());
my $CurrentDirSuffix = basename($CurrentDir);

my @PluginsToLoad;
my $CmdArgs;

my $HtmlTitle;

my $Date = localtime();

##----------------------------------------------------------------------------##
# Diagnostics
##----------------------------------------------------------------------------##

sub Diag {
  if ($UseColor) {
    print BOLD, MAGENTA "$Prog: @_";
    print RESET;
  }
  else {
    print "$Prog: @_";
  }
}

sub ErrorDiag {
  if ($UseColor) {
    print STDERR BOLD, RED "$Prog: ";
    print STDERR RESET, RED @_;
    print STDERR RESET;
  } else {
    print STDERR "$Prog: @_";
  }
}

sub DiagCrashes {
  my $Dir = shift;
  Diag ("The analyzer encountered problems on some source files.\n");
  Diag ("Preprocessed versions of these sources were deposited in '$Dir/failures'.\n");
  Diag ("Please consider submitting a bug report using these files:\n");
  Diag ("  http://clang-analyzer.llvm.org/filing_bugs.html\n")
}

sub DieDiag {
  if ($UseColor) {
    print STDERR BOLD, RED "$Prog: ";
    print STDERR RESET, RED @_;
    print STDERR RESET;
  }
  else {
    print STDERR "$Prog: ", @_;
  }
  exit 1;
}

##----------------------------------------------------------------------------##
# Print default checker names
##----------------------------------------------------------------------------##

if (grep /^--help-checkers$/, @ARGV) {
    my @options = qx($0 -h);
    foreach (@options) {
	next unless /^ \+/;
	s/^\s*//;
	my ($sign, $name, @text) = split ' ', $_;
	print $name, $/ if $sign eq '+';
    }
    exit 0;
}

##----------------------------------------------------------------------------##
# Declaration of Clang options.  Populated later.
##----------------------------------------------------------------------------##

my $Clang;
my $ClangSB;
my $ClangCXX;
my $ClangVersion;

##----------------------------------------------------------------------------##
# GetHTMLRunDir - Construct an HTML directory name for the current sub-run.
##----------------------------------------------------------------------------##

sub GetHTMLRunDir {
  die "Not enough arguments." if (@_ == 0);
  my $Dir = shift @_;
  my $TmpMode = 0;
  if (!defined $Dir) {
    $Dir = $ENV{'TMPDIR'} || $ENV{'TEMP'} || $ENV{'TMP'} || "/tmp";
    $TmpMode = 1;
  }

  # Chop off any trailing '/' characters.
  while ($Dir =~ /\/$/) { chop $Dir; }

  # Get current date and time.
  my @CurrentTime = localtime();
  my $year  = $CurrentTime[5] + 1900;
  my $day   = $CurrentTime[3];
  my $month = $CurrentTime[4] + 1;
  my $hour =  $CurrentTime[2];
  my $min =   $CurrentTime[1];
  my $sec =   $CurrentTime[0];

  my $TimeString = sprintf("%02d%02d%02d", $hour, $min, $sec);
  my $DateString = sprintf("%d-%02d-%02d-%s-$$",
                           $year, $month, $day, $TimeString);

  # Determine the run number.
  my $RunNumber;

  if (-d $Dir) {
    if (! -r $Dir) {
      DieDiag("directory '$Dir' exists but is not readable.\n");
    }
    # Iterate over all files in the specified directory.
    my $max = 0;
    opendir(DIR, $Dir);
    my @FILES = grep { -d "$Dir/$_" } readdir(DIR);
    closedir(DIR);

    foreach my $f (@FILES) {
      # Strip the prefix '$Prog-' if we are dumping files to /tmp.
      if ($TmpMode) {
        next if (!($f =~ /^$Prog-(.+)/));
        $f = $1;
      }

      my @x = split/-/, $f;
      next if (scalar(@x) != 4);
      next if ($x[0] != $year);
      next if ($x[1] != $month);
      next if ($x[2] != $day);
      next if ($x[3] != $TimeString);
      next if ($x[4] != $$);

      if ($x[5] > $max) {
        $max = $x[5];
      }
    }

    $RunNumber = $max + 1;
  }
  else {

    if (-x $Dir) {
      DieDiag("'$Dir' exists but is not a directory.\n");
    }

    if ($TmpMode) {
      DieDiag("The directory '/tmp' does not exist or cannot be accessed.\n");
    }

    # $Dir does not exist.  It will be automatically created by the
    # clang driver.  Set the run number to 1.

    $RunNumber = 1;
  }

  die "RunNumber must be defined!" if (!defined $RunNumber);

  # Append the run number.
  my $NewDir;
  if ($TmpMode) {
    $NewDir = "$Dir/$Prog-$DateString-$RunNumber";
  }
  else {
    $NewDir = "$Dir/$DateString-$RunNumber";
  }

  # Make sure that the directory does not exist in order to avoid hijack.
  if (-e $NewDir) {
      DieDiag("The directory '$NewDir' already exists.\n");
  }

  mkpath($NewDir);
  return $NewDir;
}

sub SetHtmlEnv {

  die "Wrong number of arguments." if (scalar(@_) != 2);

  my $Args = shift;
  my $Dir = shift;

  die "No build command." if (scalar(@$Args) == 0);

  my $Cmd = $$Args[0];

  if ($Cmd =~ /configure/ || $Cmd =~ /autogen/) {
    return;
  }

  if ($Verbose) {
    Diag("Emitting reports for this run to '$Dir'.\n");
  }

  $ENV{'CCC_ANALYZER_HTML'} = $Dir;
}

##----------------------------------------------------------------------------##
# ComputeDigest - Compute a digest of the specified file.
##----------------------------------------------------------------------------##

sub ComputeDigest {
  my $FName = shift;
  DieDiag("Cannot read $FName to compute Digest.\n") if (! -r $FName);

  # Use Digest::MD5.  We don't have to be cryptographically secure.  We're
  # just looking for duplicate files that come from a non-malicious source.
  # We use Digest::MD5 because it is a standard Perl module that should
  # come bundled on most systems.
  open(FILE, $FName) or DieDiag("Cannot open $FName when computing Digest.\n");
  binmode FILE;
  my $Result = Digest::MD5->new->addfile(*FILE)->hexdigest;
  close(FILE);

  # Return the digest.
  return $Result;
}

##----------------------------------------------------------------------------##
#  UpdatePrefix - Compute the common prefix of files.
##----------------------------------------------------------------------------##

my $Prefix;

sub UpdatePrefix {
  my $x = shift;
  my $y = basename($x);
  $x =~ s/\Q$y\E$//;

  if (!defined $Prefix) {
    $Prefix = $x;
    return;
  }

  chop $Prefix while (!($x =~ /^\Q$Prefix/));
}

sub GetPrefix {
  return $Prefix;
}

##----------------------------------------------------------------------------##
#  UpdateInFilePath - Update the path in the report file.
##----------------------------------------------------------------------------##

sub UpdateInFilePath {
  my $fname = shift;
  my $regex = shift;
  my $newtext = shift;

  open (RIN, $fname) or die "cannot open $fname";
  open (ROUT, ">", "$fname.tmp") or die "cannot open $fname.tmp";

  while (<RIN>) {
    s/$regex/$newtext/;
    print ROUT $_;
  }

  close (ROUT);
  close (RIN);
  rename("$fname.tmp", $fname)
}

##----------------------------------------------------------------------------##
# AddStatLine - Decode and insert a statistics line into the database.
##----------------------------------------------------------------------------##

sub AddStatLine {
  my $Line  = shift;
  my $Stats = shift;
  my $File  = shift;

  print $Line . "\n";

  my $Regex = qr/(.*?)\ ->\ Total\ CFGBlocks:\ (\d+)\ \|\ Unreachable
      \ CFGBlocks:\ (\d+)\ \|\ Exhausted\ Block:\ (yes|no)\ \|\ Empty\ WorkList:
      \ (yes|no)/x;

  if ($Line !~ $Regex) {
    return;
  }

  # Create a hash of the interesting fields
  my $Row = {
    Filename    => $File,
    Function    => $1,
    Total       => $2,
    Unreachable => $3,
    Aborted     => $4,
    Empty       => $5
  };

  # Add them to the stats array
  push @$Stats, $Row;
}

##----------------------------------------------------------------------------##
# ScanFile - Scan a report file for various identifying attributes.
##----------------------------------------------------------------------------##

# Sometimes a source file is scanned more than once, and thus produces
# multiple error reports.  We use a cache to solve this problem.

my %AlreadyScanned;

sub ScanFile {

  my $Index = shift;
  my $Dir = shift;
  my $FName = shift;
  my $Stats = shift;

  # Compute a digest for the report file.  Determine if we have already
  # scanned a file that looks just like it.

  my $digest = ComputeDigest("$Dir/$FName");

  if (defined $AlreadyScanned{$digest}) {
    # Redundant file.  Remove it.
    unlink("$Dir/$FName");
    return;
  }

  $AlreadyScanned{$digest} = 1;

  # At this point the report file is not world readable.  Make it happen.
  chmod(0644, "$Dir/$FName");

  # Scan the report file for tags.
  open(IN, "$Dir/$FName") or DieDiag("Cannot open '$Dir/$FName'\n");

  my $BugType        = "";
  my $BugFile        = "";
  my $BugFunction    = "";
  my $BugCategory    = "";
  my $BugDescription = "";
  my $BugPathLength  = 1;
  my $BugLine        = 0;

  while (<IN>) {
    last if (/<!-- BUGMETAEND -->/);

    if (/<!-- BUGTYPE (.*) -->$/) {
      $BugType = $1;
    }
    elsif (/<!-- BUGFILE (.*) -->$/) {
      $BugFile = abs_path($1);
      UpdatePrefix($BugFile);
    }
    elsif (/<!-- BUGPATHLENGTH (.*) -->$/) {
      $BugPathLength = $1;
    }
    elsif (/<!-- BUGLINE (.*) -->$/) {
      $BugLine = $1;
    }
    elsif (/<!-- BUGCATEGORY (.*) -->$/) {
      $BugCategory = $1;
    }
    elsif (/<!-- BUGDESC (.*) -->$/) {
      $BugDescription = $1;
    }
    elsif (/<!-- FUNCTIONNAME (.*) -->$/) {
      $BugFunction = $1;
    }

  }


  close(IN);

  if (!defined $BugCategory) {
    $BugCategory = "Other";
  }

  # Don't add internal statistics to the bug reports
  if ($BugCategory =~ /statistics/i) {
    AddStatLine($BugDescription, $Stats, $BugFile);
    return;
  }

  push @$Index,[ $FName, $BugCategory, $BugType, $BugFile, $BugFunction, $BugLine,
                 $BugPathLength ];
}

##----------------------------------------------------------------------------##
# CopyFiles - Copy resource files to target directory.
##----------------------------------------------------------------------------##

sub CopyFiles {

  my $Dir = shift;

  my $JS = Cwd::realpath("$RealBin/../lib/static-analyzer/sorttable.js");

  DieDiag("Cannot find 'sorttable.js'.\n")
    if (! -r $JS);

  copy($JS, "$Dir");

  DieDiag("Could not copy 'sorttable.js' to '$Dir'.\n")
    if (! -r "$Dir/sorttable.js");
    
  my $CSS = Cwd::realpath("$RealBin/../lib/static-analyzer/scanview.css");

  DieDiag("Cannot find 'scanview.css'.\n")
    if (! -r $CSS);

  copy($CSS, "$Dir");

  DieDiag("Could not copy 'scanview.css' to '$Dir'.\n")
    if (! -r $CSS);
}

##----------------------------------------------------------------------------##
# CalcStats - Calculates visitation statistics and returns the string.
##----------------------------------------------------------------------------##

sub CalcStats {
  my $Stats = shift;

  my $TotalBlocks = 0;
  my $UnreachedBlocks = 0;
  my $TotalFunctions = scalar(@$Stats);
  my $BlockAborted = 0;
  my $WorkListAborted = 0;
  my $Aborted = 0;

  # Calculate the unique files
  my $FilesHash = {};

  foreach my $Row (@$Stats) {
    $FilesHash->{$Row->{Filename}} = 1;
    $TotalBlocks += $Row->{Total};
    $UnreachedBlocks += $Row->{Unreachable};
    $BlockAborted++ if $Row->{Aborted} eq 'yes';
    $WorkListAborted++ if $Row->{Empty} eq 'no';
    $Aborted++ if $Row->{Aborted} eq 'yes' || $Row->{Empty} eq 'no';
  }

  my $TotalFiles = scalar(keys(%$FilesHash));

  # Calculations
  my $PercentAborted = sprintf("%.2f", $Aborted / $TotalFunctions * 100);
  my $PercentBlockAborted = sprintf("%.2f", $BlockAborted / $TotalFunctions
      * 100);
  my $PercentWorkListAborted = sprintf("%.2f", $WorkListAborted /
      $TotalFunctions * 100);
  my $PercentBlocksUnreached = sprintf("%.2f", $UnreachedBlocks / $TotalBlocks
      * 100);

  my $StatsString = "Analyzed $TotalBlocks blocks in $TotalFunctions functions"
    . " in $TotalFiles files\n"
    . "$Aborted functions aborted early ($PercentAborted%)\n"
    . "$BlockAborted had aborted blocks ($PercentBlockAborted%)\n"
    . "$WorkListAborted had unfinished worklists ($PercentWorkListAborted%)\n"
    . "$UnreachedBlocks blocks were never reached ($PercentBlocksUnreached%)\n";

  return $StatsString;
}

##----------------------------------------------------------------------------##
# Postprocess - Postprocess the results of an analysis scan.
##----------------------------------------------------------------------------##

my @filesFound;
my $baseDir;
sub FileWanted {
    my $baseDirRegEx = quotemeta $baseDir;
    my $file = $File::Find::name;

    # The name of the file is generated by clang binary (HTMLDiagnostics.cpp)
    if ($file =~ /report-.*\.html$/) {
       my $relative_file = $file;
       $relative_file =~ s/$baseDirRegEx//g;
       push @filesFound, $relative_file;
    }
}

sub Postprocess {

  my $Dir           = shift;
  my $BaseDir       = shift;
  my $AnalyzerStats = shift;
  my $KeepEmpty     = shift;

  die "No directory specified." if (!defined $Dir);

  if (! -d $Dir) {
    Diag("No bugs found.\n");
    return 0;
  }

  $baseDir = $Dir . "/";
  find({ wanted => \&FileWanted, follow => 0}, $Dir);

  if (scalar(@filesFound) == 0 and ! -e "$Dir/failures") {
    if (! $KeepEmpty) {
      Diag("Removing directory '$Dir' because it contains no reports.\n");
      rmtree($Dir) or die "Cannot rmtree '$Dir' : $!";
    }
    Diag("No bugs found.\n");
    return 0;
  }

  # Scan each report file and build an index.
  my @Index;
  my @Stats;
  foreach my $file (@filesFound) { ScanFile(\@Index, $Dir, $file, \@Stats); }

  # Scan the failures directory and use the information in the .info files
  # to update the common prefix directory.
  my @failures;
  my @attributes_ignored;
  if (-d "$Dir/failures") {
    opendir(DIR, "$Dir/failures");
    @failures = grep { /[.]info.txt$/ && !/attribute_ignored/; } readdir(DIR);
    closedir(DIR);
    opendir(DIR, "$Dir/failures");
    @attributes_ignored = grep { /^attribute_ignored/; } readdir(DIR);
    closedir(DIR);
    foreach my $file (@failures) {
      open IN, "$Dir/failures/$file" or DieDiag("cannot open $file\n");
      my $Path = <IN>;
      if (defined $Path) { UpdatePrefix($Path); }
      close IN;
    }
  }

  # Generate an index.html file.
  my $FName = "$Dir/index.html";
  open(OUT, ">", $FName) or DieDiag("Cannot create file '$FName'\n");

  # Print out the header.

print OUT <<ENDTEXT;
<html>
<head>
<title>${HtmlTitle}</title>
<link type="text/css" rel="stylesheet" href="scanview.css"/>
<script src="sorttable.js"></script>
<script language='javascript' type="text/javascript">
function SetDisplay(RowClass, DisplayVal)
{
  var Rows = document.getElementsByTagName("tr");
  for ( var i = 0 ; i < Rows.length; ++i ) {
    if (Rows[i].className == RowClass) {
      Rows[i].style.display = DisplayVal;
    }
  }
}

function CopyCheckedStateToCheckButtons(SummaryCheckButton) {
  var Inputs = document.getElementsByTagName("input");
  for ( var i = 0 ; i < Inputs.length; ++i ) {
    if (Inputs[i].type == "checkbox") {
      if(Inputs[i] != SummaryCheckButton) {
        Inputs[i].checked = SummaryCheckButton.checked;
        Inputs[i].onclick();
	  }
    }
  }
}

function returnObjById( id ) {
    if (document.getElementById)
        var returnVar = document.getElementById(id);
    else if (document.all)
        var returnVar = document.all[id];
    else if (document.layers)
        var returnVar = document.layers[id];
    return returnVar;
}

var NumUnchecked = 0;

function ToggleDisplay(CheckButton, ClassName) {
  if (CheckButton.checked) {
    SetDisplay(ClassName, "");
    if (--NumUnchecked == 0) {
      returnObjById("AllBugsCheck").checked = true;
    }
  }
  else {
    SetDisplay(ClassName, "none");
    NumUnchecked++;
    returnObjById("AllBugsCheck").checked = false;
  }
}
</script>
<!-- SUMMARYENDHEAD -->
</head>
<body>
<h1>${HtmlTitle}</h1>

<table>
<tr><th>User:</th><td>${UserName}\@${HostName}</td></tr>
<tr><th>Working Directory:</th><td>${CurrentDir}</td></tr>
<tr><th>Command Line:</th><td>${CmdArgs}</td></tr>
<tr><th>Clang Version:</th><td>${ClangVersion}</td></tr>
<tr><th>Date:</th><td>${Date}</td></tr>
ENDTEXT

print OUT "<tr><th>Version:</th><td>${BuildName} (${BuildDate})</td></tr>\n"
  if (defined($BuildName) && defined($BuildDate));

print OUT <<ENDTEXT;
</table>
ENDTEXT

  if (scalar(@filesFound)) {
    # Print out the summary table.
    my %Totals;

    for my $row ( @Index ) {
      my $bug_type = ($row->[2]);
      my $bug_category = ($row->[1]);
      my $key = "$bug_category:$bug_type";

      if (!defined $Totals{$key}) { $Totals{$key} = [1,$bug_category,$bug_type]; }
      else { $Totals{$key}->[0]++; }
    }

    print OUT "<h2>Bug Summary</h2>";

    if (defined $BuildName) {
      print OUT "\n<p>Results in this analysis run are based on analyzer build <b>$BuildName</b>.</p>\n"
    }

  my $TotalBugs = scalar(@Index);
print OUT <<ENDTEXT;
<table>
<thead><tr><td>Bug Type</td><td>Quantity</td><td class="sorttable_nosort">Display?</td></tr></thead>
<tr style="font-weight:bold"><td class="SUMM_DESC">All Bugs</td><td class="Q">$TotalBugs</td><td><center><input type="checkbox" id="AllBugsCheck" onClick="CopyCheckedStateToCheckButtons(this);" checked/></center></td></tr>
ENDTEXT

    my $last_category;

    for my $key (
      sort {
        my $x = $Totals{$a};
        my $y = $Totals{$b};
        my $res = $x->[1] cmp $y->[1];
        $res = $x->[2] cmp $y->[2] if ($res == 0);
        $res
      } keys %Totals )
    {
      my $val = $Totals{$key};
      my $category = $val->[1];
      if (!defined $last_category or $last_category ne $category) {
        $last_category = $category;
        print OUT "<tr><th>$category</th><th colspan=2></th></tr>\n";
      }
      my $x = lc $key;
      $x =~ s/[ ,'":\/()]+/_/g;
      print OUT "<tr><td class=\"SUMM_DESC\">";
      print OUT $val->[2];
      print OUT "</td><td class=\"Q\">";
      print OUT $val->[0];
      print OUT "</td><td><center><input type=\"checkbox\" onClick=\"ToggleDisplay(this,'bt_$x');\" checked/></center></td></tr>\n";
    }

  # Print out the table of errors.

print OUT <<ENDTEXT;
</table>
<h2>Reports</h2>

<table class="sortable" style="table-layout:automatic">
<thead><tr>
  <td>Bug Group</td>
  <td class="sorttable_sorted">Bug Type<span id="sorttable_sortfwdind">&nbsp;&#x25BE;</span></td>
  <td>File</td>
  <td>Function/Method</td>
  <td class="Q">Line</td>
  <td class="Q">Path Length</td>
  <td class="sorttable_nosort"></td>
  <!-- REPORTBUGCOL -->
</tr></thead>
<tbody>
ENDTEXT

    my $prefix = GetPrefix();
    my $regex;
    my $InFileRegex;
    my $InFilePrefix = "File:</td><td>";

    if (defined $prefix) {
      $regex = qr/^\Q$prefix\E/is;
      $InFileRegex = qr/\Q$InFilePrefix$prefix\E/is;
    }

    for my $row ( sort { $a->[2] cmp $b->[2] } @Index ) {
      my $x = "$row->[1]:$row->[2]";
      $x = lc $x;
      $x =~ s/[ ,'":\/()]+/_/g;

      my $ReportFile = $row->[0];

      print OUT "<tr class=\"bt_$x\">";
      print OUT "<td class=\"DESC\">";
      print OUT $row->[1];
      print OUT "</td>";
      print OUT "<td class=\"DESC\">";
      print OUT $row->[2];
      print OUT "</td>";

      # Update the file prefix.
      my $fname = $row->[3];

      if (defined $regex) {
        $fname =~ s/$regex//;
        UpdateInFilePath("$Dir/$ReportFile", $InFileRegex, $InFilePrefix)
      }

      print OUT "<td>";
      my @fname = split /\//,$fname;
      if ($#fname > 0) {
        while ($#fname >= 0) {
          my $x = shift @fname;
          print OUT $x;
          if ($#fname >= 0) {
            print OUT "<span class=\"W\"> </span>/";
          }
        }
      }
      else {
        print OUT $fname;
      }
      print OUT "</td>";

      print OUT "<td class=\"DESC\">";
      print OUT $row->[4];
      print OUT "</td>";

      # Print out the quantities.
      for my $j ( 5 .. 6 ) {
        print OUT "<td class=\"Q\">$row->[$j]</td>";
      }

      # Print the rest of the columns.
      for (my $j = 7; $j <= $#{$row}; ++$j) {
        print OUT "<td>$row->[$j]</td>"
      }

      # Emit the "View" link.
      print OUT "<td><a href=\"$ReportFile#EndPath\">View Report</a></td>";

      # Emit REPORTBUG markers.
      print OUT "\n<!-- REPORTBUG id=\"$ReportFile\" -->\n";

      # End the row.
      print OUT "</tr>\n";
    }

    print OUT "</tbody>\n</table>\n\n";
  }

  if (scalar (@failures) || scalar(@attributes_ignored)) {
    print OUT "<h2>Analyzer Failures</h2>\n";

    if (scalar @attributes_ignored) {
      print OUT "The analyzer's parser ignored the following attributes:<p>\n";
      print OUT "<table>\n";
      print OUT "<thead><tr><td>Attribute</td><td>Source File</td><td>Preprocessed File</td><td>STDERR Output</td></tr></thead>\n";
      foreach my $file (sort @attributes_ignored) {
        die "cannot demangle attribute name\n" if (! ($file =~ /^attribute_ignored_(.+).txt/));
        my $attribute = $1;
        # Open the attribute file to get the first file that failed.
        next if (!open (ATTR, "$Dir/failures/$file"));
        my $ppfile = <ATTR>;
        chomp $ppfile;
        close ATTR;
        next if (! -e "$Dir/failures/$ppfile");
        # Open the info file and get the name of the source file.
        open (INFO, "$Dir/failures/$ppfile.info.txt") or
          die "Cannot open $Dir/failures/$ppfile.info.txt\n";
        my $srcfile = <INFO>;
        chomp $srcfile;
        close (INFO);
        # Print the information in the table.
        my $prefix = GetPrefix();
        if (defined $prefix) { $srcfile =~ s/^\Q$prefix//; }
        print OUT "<tr><td>$attribute</td><td>$srcfile</td><td><a href=\"failures/$ppfile\">$ppfile</a></td><td><a href=\"failures/$ppfile.stderr.txt\">$ppfile.stderr.txt</a></td></tr>\n";
        my $ppfile_clang = $ppfile;
        $ppfile_clang =~ s/[.](.+)$/.clang.$1/;
        print OUT "  <!-- REPORTPROBLEM src=\"$srcfile\" file=\"failures/$ppfile\" clangfile=\"failures/$ppfile_clang\" stderr=\"failures/$ppfile.stderr.txt\" info=\"failures/$ppfile.info.txt\" -->\n";
      }
      print OUT "</table>\n";
    }

    if (scalar @failures) {
      print OUT "<p>The analyzer had problems processing the following files:</p>\n";
      print OUT "<table>\n";
      print OUT "<thead><tr><td>Problem</td><td>Source File</td><td>Preprocessed File</td><td>STDERR Output</td></tr></thead>\n";
      foreach my $file (sort @failures) {
        $file =~ /(.+).info.txt$/;
        # Get the preprocessed file.
        my $ppfile = $1;
        # Open the info file and get the name of the source file.
        open (INFO, "$Dir/failures/$file") or
          die "Cannot open $Dir/failures/$file\n";
        my $srcfile = <INFO>;
        chomp $srcfile;
        my $problem = <INFO>;
        chomp $problem;
        close (INFO);
        # Print the information in the table.
        my $prefix = GetPrefix();
        if (defined $prefix) { $srcfile =~ s/^\Q$prefix//; }
        print OUT "<tr><td>$problem</td><td>$srcfile</td><td><a href=\"failures/$ppfile\">$ppfile</a></td><td><a href=\"failures/$ppfile.stderr.txt\">$ppfile.stderr.txt</a></td></tr>\n";
        my $ppfile_clang = $ppfile;
        $ppfile_clang =~ s/[.](.+)$/.clang.$1/;
        print OUT "  <!-- REPORTPROBLEM src=\"$srcfile\" file=\"failures/$ppfile\" clangfile=\"failures/$ppfile_clang\" stderr=\"failures/$ppfile.stderr.txt\" info=\"failures/$ppfile.info.txt\" -->\n";
      }
      print OUT "</table>\n";
    }
    print OUT "<p>Please consider submitting preprocessed files as <a href=\"http://clang-analyzer.llvm.org/filing_bugs.html\">bug reports</a>. <!-- REPORTCRASHES --> </p>\n";
  }

  print OUT "</body></html>\n";
  close(OUT);
  CopyFiles($Dir);

  # Make sure $Dir and $BaseDir are world readable/executable.
  chmod(0755, $Dir);
  if (defined $BaseDir) { chmod(0755, $BaseDir); }

  # Print statistics
  print CalcStats(\@Stats) if $AnalyzerStats;

  my $Num = scalar(@Index);
  if ($Num == 1) {
    Diag("$Num bug found.\n");
  } else {
    Diag("$Num bugs found.\n");
  }
  if ($Num > 0 && -r "$Dir/index.html") {
    Diag("Run 'scan-view $Dir' to examine bug reports.\n");
  }

  DiagCrashes($Dir) if (scalar @failures || scalar @attributes_ignored);

  return $Num;
}

##----------------------------------------------------------------------------##
# RunBuildCommand - Run the build command.
##----------------------------------------------------------------------------##

sub AddIfNotPresent {
  my $Args = shift;
  my $Arg = shift;
  my $found = 0;

  foreach my $k (@$Args) {
    if ($k eq $Arg) {
      $found = 1;
      last;
    }
  }

  if ($found == 0) {
    push @$Args, $Arg;
  }
}

sub SetEnv {
  my $Options = shift @_;
  foreach my $opt ('CC', 'CXX', 'CLANG', 'CLANG_CXX',
                    'CCC_ANALYZER_ANALYSIS', 'CCC_ANALYZER_PLUGINS',
                    'CCC_ANALYZER_CONFIG') {
    die "$opt is undefined\n" if (!defined $opt);
    $ENV{$opt} = $Options->{$opt};
  }
  foreach my $opt ('CCC_ANALYZER_STORE_MODEL',
                    'CCC_ANALYZER_PLUGINS',
                    'CCC_ANALYZER_INTERNAL_STATS',
                    'CCC_ANALYZER_OUTPUT_FORMAT') {
    my $x = $Options->{$opt};
    if (defined $x) { $ENV{$opt} = $x }
  }
  my $Verbose = $Options->{'VERBOSE'};
  if ($Verbose >= 2) {
    $ENV{'CCC_ANALYZER_VERBOSE'} = 1;
  }
  if ($Verbose >= 3) {
    $ENV{'CCC_ANALYZER_LOG'} = 1;
  }
}

# The flag corresponding to the --override-compiler command line option.
my $OverrideCompiler = 0;

sub RunXcodebuild {
  my $Args = shift;
  my $IgnoreErrors = shift;
  my $CCAnalyzer = shift;
  my $CXXAnalyzer = shift;
  my $Options = shift;

  if ($IgnoreErrors) {
    AddIfNotPresent($Args,"-PBXBuildsContinueAfterErrors=YES");
  }

  # Detect the version of Xcode.  If Xcode 4.6 or higher, use new
  # in situ support for analyzer interposition without needed to override
  # the compiler.
  open(DETECT_XCODE, "-|", $Args->[0], "-version") or
    die "error: cannot detect version of xcodebuild\n";

  my $oldBehavior = 1;

  while(<DETECT_XCODE>) {
    if (/^Xcode (.+)$/) {
      my $ver = $1;
      if ($ver =~ /^([0-9]+[.][0-9]+)[^0-9]?/) {
        if ($1 >= 4.6) {
          $oldBehavior = 0;
          last;
        }
      }
    }
  }
  close(DETECT_XCODE);

  # If --override-compiler is explicitely requested, resort to the old
  # behavior regardless of Xcode version.
  if ($OverrideCompiler) {
    $oldBehavior = 1;
  }

  if ($oldBehavior == 0) {
    my $OutputDir = $Options->{"OUTPUT_DIR"};
    my $CLANG = $Options->{"CLANG"};
    my $OtherFlags = $Options->{"CCC_ANALYZER_ANALYSIS"};
    push @$Args,
        "RUN_CLANG_STATIC_ANALYZER=YES",
        "CLANG_ANALYZER_OUTPUT=plist-html",
        "CLANG_ANALYZER_EXEC=$CLANG",
        "CLANG_ANALYZER_OUTPUT_DIR=$OutputDir",
        "CLANG_ANALYZER_OTHER_FLAGS=$OtherFlags";

    return (system(@$Args) >> 8);
  }

  # Default to old behavior where we insert a bogus compiler.
  SetEnv($Options);

  # Check if using iPhone SDK 3.0 (simulator).  If so the compiler being
  # used should be gcc-4.2.
  if (!defined $ENV{"CCC_CC"}) {
    for (my $i = 0 ; $i < scalar(@$Args); ++$i) {
      if ($Args->[$i] eq "-sdk" && $i + 1 < scalar(@$Args)) {
        if (@$Args[$i+1] =~ /^iphonesimulator3/) {
          $ENV{"CCC_CC"} = "gcc-4.2";
          $ENV{"CCC_CXX"} = "g++-4.2";
        }
      }
    }
  }

  # Disable PCH files until clang supports them.
  AddIfNotPresent($Args,"GCC_PRECOMPILE_PREFIX_HEADER=NO");

  # When 'CC' is set, xcodebuild uses it to do all linking, even if we are
  # linking C++ object files.  Set 'LDPLUSPLUS' so that xcodebuild uses 'g++'
  # (via c++-analyzer) when linking such files.
  $ENV{"LDPLUSPLUS"} = $CXXAnalyzer;

  return (system(@$Args) >> 8);
}

sub RunBuildCommand {
  my $Args = shift;
  my $IgnoreErrors = shift;
  my $Cmd = $Args->[0];
  my $CCAnalyzer = shift;
  my $CXXAnalyzer = shift;
  my $Options = shift;

  if ($Cmd =~ /\bxcodebuild$/) {
    return RunXcodebuild($Args, $IgnoreErrors, $CCAnalyzer, $CXXAnalyzer, $Options);
  }

  # Setup the environment.
  SetEnv($Options);

  if ($Cmd =~ /(.*\/?gcc[^\/]*$)/ or
      $Cmd =~ /(.*\/?cc[^\/]*$)/ or
      $Cmd =~ /(.*\/?llvm-gcc[^\/]*$)/ or
      $Cmd =~ /(.*\/?clang$)/ or
      $Cmd =~ /(.*\/?ccc-analyzer[^\/]*$)/) {

    if (!($Cmd =~ /ccc-analyzer/) and !defined $ENV{"CCC_CC"}) {
      $ENV{"CCC_CC"} = $1;
    }

    shift @$Args;
    unshift @$Args, $CCAnalyzer;
  }
  elsif ($Cmd =~ /(.*\/?g\+\+[^\/]*$)/ or
        $Cmd =~ /(.*\/?c\+\+[^\/]*$)/ or
        $Cmd =~ /(.*\/?llvm-g\+\+[^\/]*$)/ or
        $Cmd =~ /(.*\/?clang\+\+$)/ or
        $Cmd =~ /(.*\/?c\+\+-analyzer[^\/]*$)/) {
    if (!($Cmd =~ /c\+\+-analyzer/) and !defined $ENV{"CCC_CXX"}) {
      $ENV{"CCC_CXX"} = $1;
    }
    shift @$Args;
    unshift @$Args, $CXXAnalyzer;
  }
  elsif ($Cmd eq "make" or $Cmd eq "gmake") {
    AddIfNotPresent($Args, "CC=$CCAnalyzer");
    AddIfNotPresent($Args, "CXX=$CXXAnalyzer");
    if ($IgnoreErrors) {
      AddIfNotPresent($Args,"-k");
      AddIfNotPresent($Args,"-i");
    }
  }

  return (system(@$Args) >> 8);
}

##----------------------------------------------------------------------------##
# DisplayHelp - Utility function to display all help options.
##----------------------------------------------------------------------------##

sub DisplayHelp {

print <<ENDTEXT;
USAGE: $Prog [options] <build command> [build options]

ENDTEXT

  if (defined $BuildName) {
    print "ANALYZER BUILD: $BuildName ($BuildDate)\n\n";
  }

print <<ENDTEXT;
OPTIONS:

 -analyze-headers

   Also analyze functions in #included files.  By default, such functions
   are skipped unless they are called by functions within the main source file.

 -o <output location>

   Specifies the output directory for analyzer reports. Subdirectories will be
   created as needed to represent separate "runs" of the analyzer. If this
   option is not specified, a directory is created in /tmp (TMPDIR on Mac OS X)
   to store the reports.

 -h
 --help

   Display this message.

 -k
 --keep-going

   Add a "keep on going" option to the specified build command. This option
   currently supports make and xcodebuild. This is a convenience option; one
   can specify this behavior directly using build options.

 --html-title [title]
 --html-title=[title]

   Specify the title used on generated HTML pages. If not specified, a default
   title will be used.

 -plist

   By default the output of scan-build is a set of HTML files. This option
   outputs the results as a set of .plist files.

 -plist-html

   By default the output of scan-build is a set of HTML files. This option
   outputs the results as a set of HTML and .plist files.

 --status-bugs

   By default, the exit status of scan-build is the same as the executed build
   command. Specifying this option causes the exit status of scan-build to be 1
   if it found potential bugs and 0 otherwise.

 --use-cc [compiler path]
 --use-cc=[compiler path]

   scan-build analyzes a project by interposing a "fake compiler", which
   executes a real compiler for compilation and the static analyzer for analysis.
   Because of the current implementation of interposition, scan-build does not
   know what compiler your project normally uses.  Instead, it simply overrides
   the CC environment variable, and guesses your default compiler.

   In the future, this interposition mechanism to be improved, but if you need
   scan-build to use a specific compiler for *compilation* then you can use
   this option to specify a path to that compiler.

 --use-c++ [compiler path]
 --use-c++=[compiler path]

   This is the same as "-use-cc" but for C++ code.

 -v

   Enable verbose output from scan-build. A second and third '-v' increases
   verbosity.

 -V
 --view

   View analysis results in a web browser when the build completes.

ADVANCED OPTIONS:

 -no-failure-reports

   Do not create a 'failures' subdirectory that includes analyzer crash reports
   and preprocessed source files.

 -stats

   Generates visitation statistics for the project being analyzed.

 -maxloop <loop count>

   Specifiy the number of times a block can be visited before giving up.
   Default is 4. Increase for more comprehensive coverage at a cost of speed.

 -internal-stats

   Generate internal analyzer statistics.

 --use-analyzer [Xcode|path to clang]
 --use-analyzer=[Xcode|path to clang]

   scan-build uses the 'clang' executable relative to itself for static
   analysis. One can override this behavior with this option by using the
   'clang' packaged with Xcode (on OS X) or from the PATH.

 --keep-empty

   Don't remove the build results directory even if no issues were reported.

 --override-compiler
   Always resort to the ccc-analyzer even when better interposition methods
   are available.

 -analyzer-config <options>

   Provide options to pass through to the analyzer's -analyzer-config flag.
   Several options are separated with comma: 'key1=val1,key2=val2'

   Available options:
     * stable-report-filename=true or false (default)
       Switch the page naming to:
       report-<filename>-<function/method name>-<id>.html
       instead of report-XXXXXX.html

CONTROLLING CHECKERS:

 A default group of checkers are always run unless explicitly disabled.
 Checkers may be enabled/disabled using the following options:

 -enable-checker [checker name]
 -disable-checker [checker name]

LOADING CHECKERS:

 Loading external checkers using the clang plugin interface:

 -load-plugin [plugin library]
ENDTEXT

# Query clang for list of checkers that are enabled.

# create a list to load the plugins via the 'Xclang' command line
# argument
my @PluginLoadCommandline_xclang;
foreach my $param ( @PluginsToLoad ) {
  push ( @PluginLoadCommandline_xclang, "-Xclang" );
  push ( @PluginLoadCommandline_xclang, $param );
}
my %EnabledCheckers;
foreach my $lang ("c", "objective-c", "objective-c++", "c++") {
  pipe(FROM_CHILD, TO_PARENT);
  my $pid = fork();
  if ($pid == 0) {
    close FROM_CHILD;
    open(STDOUT,">&", \*TO_PARENT);
    open(STDERR,">&", \*TO_PARENT);
    exec $Clang, ( @PluginLoadCommandline_xclang, '--analyze', '-x', $lang, '-', '-###');
  }
  close(TO_PARENT);
  while(<FROM_CHILD>) {
    foreach my $val (split /\s+/) {
      $val =~ s/\"//g;
      if ($val =~ /-analyzer-checker\=([^\s]+)/) {
        $EnabledCheckers{$1} = 1;
      }
    }
  }
  waitpid($pid,0);
  close(FROM_CHILD);
}

# Query clang for complete list of checkers.
if (defined $Clang && -x $Clang) {
  pipe(FROM_CHILD, TO_PARENT);
  my $pid = fork();
  if ($pid == 0) {
    close FROM_CHILD;
    open(STDOUT,">&", \*TO_PARENT);
    open(STDERR,">&", \*TO_PARENT);
    exec $Clang, ('-cc1', @PluginsToLoad , '-analyzer-checker-help');
  }
  close(TO_PARENT);
  my $foundCheckers = 0;
  while(<FROM_CHILD>) {
    if (/CHECKERS:/) {
      $foundCheckers = 1;
      last;
    }
  }
  if (!$foundCheckers) {
    print "  *** Could not query Clang for the list of available checkers.";
  }
  else {
    print("\nAVAILABLE CHECKERS:\n\n");
    my $skip = 0;
    while(<FROM_CHILD>) {
      if (/experimental/) {
        $skip = 1;
        next;
      }
      if ($skip) {
        next if (!/^\s\s[^\s]/);
        $skip = 0;
      }
      s/^\s\s//;
      if (/^([^\s]+)/) {
        # Is the checker enabled?
        my $checker = $1;
        my $enabled = 0;
        my $aggregate = "";
        foreach my $domain (split /\./, $checker) {
          $aggregate .= $domain;
          if ($EnabledCheckers{$aggregate}) {
            $enabled =1;
            last;
          }
          # append a dot, if an additional domain is added in the next iteration
          $aggregate .= ".";
        }

        if ($enabled) {
          print " + ";
        }
        else {
          print "   ";
        }
      }
      else {
        print "   ";
      }
      print $_;
    }
    print "\nNOTE: \"+\" indicates that an analysis is enabled by default.\n"
  }
  waitpid($pid,0);
  close(FROM_CHILD);
}

print <<ENDTEXT

BUILD OPTIONS

 You can specify any build option acceptable to the build command.

EXAMPLE

 scan-build -o /tmp/myhtmldir make -j4

The above example causes analysis reports to be deposited into a subdirectory
of "/tmp/myhtmldir" and to run "make" with the "-j4" option. A different
subdirectory is created each time scan-build analyzes a project. The analyzer
should support most parallel builds, but not distributed builds.

ENDTEXT
}

##----------------------------------------------------------------------------##
# HtmlEscape - HTML entity encode characters that are special in HTML
##----------------------------------------------------------------------------##

sub HtmlEscape {
  # copy argument to new variable so we don't clobber the original
  my $arg = shift || '';
  my $tmp = $arg;
  $tmp =~ s/&/&amp;/g;
  $tmp =~ s/</&lt;/g;
  $tmp =~ s/>/&gt;/g;
  return $tmp;
}

##----------------------------------------------------------------------------##
# ShellEscape - backslash escape characters that are special to the shell
##----------------------------------------------------------------------------##

sub ShellEscape {
  # copy argument to new variable so we don't clobber the original
  my $arg = shift || '';
  if ($arg =~ /["\s]/) { return "'" . $arg . "'"; }
  return $arg;
}

##----------------------------------------------------------------------------##
# Process command-line arguments.
##----------------------------------------------------------------------------##

my $AnalyzeHeaders = 0;
my $HtmlDir;           # Parent directory to store HTML files.
my $IgnoreErrors = 0;  # Ignore build errors.
my $ViewResults  = 0;  # View results when the build terminates.
my $ExitStatusFoundBugs = 0; # Exit status reflects whether bugs were found
my $KeepEmpty    = 0;  # Don't remove output directory even with 0 results.
my @AnalysesToRun;
my $StoreModel;
my $ConstraintsModel;
my $InternalStats;
my @ConfigOptions;
my $OutputFormat = "html";
my $AnalyzerStats = 0;
my $MaxLoop = 0;
my $RequestDisplayHelp = 0;
my $ForceDisplayHelp = 0;
my $AnalyzerDiscoveryMethod;

if (!@ARGV) {
  $ForceDisplayHelp = 1
}

while (@ARGV) {

  # Scan for options we recognize.

  my $arg = $ARGV[0];

  if ($arg eq "-h" or $arg eq "--help") {
    $RequestDisplayHelp = 1;
    shift @ARGV;
    next;
  }

  if ($arg eq '-analyze-headers') {
    shift @ARGV;
    $AnalyzeHeaders = 1;
    next;
  }

  if ($arg eq "-o") {
    shift @ARGV;

    if (!@ARGV) {
      DieDiag("'-o' option requires a target directory name.\n");
    }

    # Construct an absolute path.  Uses the current working directory
    # as a base if the original path was not absolute.
    $HtmlDir = abs_path(shift @ARGV);

    next;
  }

  if ($arg =~ /^--html-title(=(.+))?$/) {
    shift @ARGV;

    if (!defined $2 || $2 eq '') {
      if (!@ARGV) {
        DieDiag("'--html-title' option requires a string.\n");
      }

      $HtmlTitle = shift @ARGV;
    } else {
      $HtmlTitle = $2;
    }

    next;
  }

  if ($arg eq "-k" or $arg eq "--keep-going") {
    shift @ARGV;
    $IgnoreErrors = 1;
    next;
  }

  if ($arg =~ /^--use-cc(=(.+))?$/) {
    shift @ARGV;
    my $cc;

    if (!defined $2 || $2 eq "") {
      if (!@ARGV) {
        DieDiag("'--use-cc' option requires a compiler executable name.\n");
      }
      $cc = shift @ARGV;
    }
    else {
      $cc = $2;
    }

    $ENV{"CCC_CC"} = $cc;
    next;
  }

  if ($arg =~ /^--use-c\+\+(=(.+))?$/) {
    shift @ARGV;
    my $cxx;

    if (!defined $2 || $2 eq "") {
      if (!@ARGV) {
        DieDiag("'--use-c++' option requires a compiler executable name.\n");
      }
      $cxx = shift @ARGV;
    }
    else {
      $cxx = $2;
    }

    $ENV{"CCC_CXX"} = $cxx;
    next;
  }

  if ($arg eq "-v") {
    shift @ARGV;
    $Verbose++;
    next;
  }

  if ($arg eq "-V" or $arg eq "--view") {
    shift @ARGV;
    $ViewResults = 1;
    next;
  }

  if ($arg eq "--status-bugs") {
    shift @ARGV;
    $ExitStatusFoundBugs = 1;
    next;
  }

  if ($arg eq "-store") {
    shift @ARGV;
    $StoreModel = shift @ARGV;
    next;
  }

  if ($arg eq "-constraints") {
    shift @ARGV;
    $ConstraintsModel = shift @ARGV;
    next;
  }

  if ($arg eq "-internal-stats") {
    shift @ARGV;
    $InternalStats = 1;
    next;
  }

  if ($arg eq "-plist") {
    shift @ARGV;
    $OutputFormat = "plist";
    next;
  }
  if ($arg eq "-plist-html") {
    shift @ARGV;
    $OutputFormat = "plist-html";
    next;
  }

  if ($arg eq "-analyzer-config") {
    shift @ARGV;
    push @ConfigOptions, "-analyzer-config", shift @ARGV;
    next;
  }

  if ($arg eq "-no-failure-reports") {
    $ENV{"CCC_REPORT_FAILURES"} = 0;
    next;
  }
  if ($arg eq "-stats") {
    shift @ARGV;
    $AnalyzerStats = 1;
    next;
  }
  if ($arg eq "-maxloop") {
    shift @ARGV;
    $MaxLoop = shift @ARGV;
    next;
  }
  if ($arg eq "-enable-checker") {
    shift @ARGV;
    push @AnalysesToRun, "-analyzer-checker", shift @ARGV;
    next;
  }
  if ($arg eq "-disable-checker") {
    shift @ARGV;
    push @AnalysesToRun, "-analyzer-disable-checker", shift @ARGV;
    next;
  }
  if ($arg eq "-load-plugin") {
    shift @ARGV;
    push @PluginsToLoad, "-load", shift @ARGV;
    next;
  }
  if ($arg eq "--use-analyzer") {
 	shift @ARGV;
  	$AnalyzerDiscoveryMethod = shift @ARGV;
	next;
  }
  if ($arg =~ /^--use-analyzer=(.+)$/) {
    shift @ARGV;
	$AnalyzerDiscoveryMethod = $1;
	next;
  }
  if ($arg eq "--keep-empty") {
    shift @ARGV;
    $KeepEmpty = 1;
    next;
  }

  if ($arg eq "--override-compiler") {
    shift @ARGV;
    $OverrideCompiler = 1;
    next;
  }

  DieDiag("unrecognized option '$arg'\n") if ($arg =~ /^-/);

  last;
}

if (!@ARGV and !$RequestDisplayHelp) {
  ErrorDiag("No build command specified.\n\n");
  $ForceDisplayHelp = 1;
}

# Find 'clang'
if (!defined $AnalyzerDiscoveryMethod) {
  $Clang = Cwd::realpath("$RealBin/bin/clang");
  if (!defined $Clang || ! -x $Clang) {
    $Clang = Cwd::realpath("$RealBin/clang");
  }
  if (!defined $Clang || ! -x $Clang) {
    $Clang = Cwd::realpath("$RealBin/hexagon-clang");
  }
  if (!defined $Clang || ! -x $Clang) {
    if (!$RequestDisplayHelp && !$ForceDisplayHelp) {
      DieDiag("error: Cannot find an executable 'clang' relative to scan-build." .
   	          "  Consider using --use-analyzer to pick a version of 'clang' to use for static analysis.\n");
    }
  }
}
else {
  if ($AnalyzerDiscoveryMethod =~ /^[Xx]code$/) {
	my $xcrun = `which xcrun`;
    chomp $xcrun;
	if ($xcrun eq "") {
  	  DieDiag("Cannot find 'xcrun' to find 'clang' for analysis.\n");
	}
    $Clang = `$xcrun -toolchain XcodeDefault -find clang`;
    chomp $Clang;
    if ($Clang eq "") {
      DieDiag("No 'clang' executable found by 'xcrun'\n");
    }
  }
  else {
    $Clang = $AnalyzerDiscoveryMethod;
	if (!defined $Clang or not -x $Clang) {
   	  DieDiag("Cannot find an executable clang at '$AnalyzerDiscoveryMethod'\n");
	}
  }
}

if ($ForceDisplayHelp || $RequestDisplayHelp) {
  DisplayHelp();
  exit $ForceDisplayHelp;
}

$ClangCXX = $Clang;
# Determine operating system under which this copy of Perl was built.
my $IsWinBuild = ($^O =~/msys|cygwin|MSWin32/);
if($IsWinBuild) {
  $ClangCXX =~ s/.exe$/++.exe/;
  # Unix system commands and some of the perl standard library
  # functions used in this script don't work on Windows.
  DieDiag("Not supported for windows. Exiting...\n");
}
else {
  $ClangCXX =~ s/\-\d+\.\d+$//;
  $ClangCXX .= "++";
}

# Make sure to use "" to handle paths with spaces.
$ClangVersion = HtmlEscape(`"$Clang" --version`);

# Determine where results go.
$CmdArgs = HtmlEscape(join(' ', map(ShellEscape($_), @ARGV)));
$HtmlTitle = "${CurrentDirSuffix} - scan-build results"
  unless (defined($HtmlTitle));

# Determine the output directory for the HTML reports.
my $BaseDir = $HtmlDir;
$HtmlDir = GetHTMLRunDir($HtmlDir);

# Determine the location of ccc-analyzer.
my $AbsRealBin = Cwd::realpath($RealBin);
my $Cmd = "$AbsRealBin/libexec/ccc-analyzer";
my $CmdCXX = "$AbsRealBin/libexec/c++-analyzer";

# Portability: use less strict but portable check -e (file exists) instead of
# non-portable -x (file is executable). On some windows ports -x just checks
# file extension to determine if a file is executable (see Perl language
# reference, perlport)
if (!defined $Cmd || ! -e $Cmd) {
  $Cmd = "$AbsRealBin/ccc-analyzer";
  DieDiag("'ccc-analyzer' does not exist at '$Cmd'\n") if(! -e $Cmd);
}
if (!defined $CmdCXX || ! -e $CmdCXX) {
  $CmdCXX = "$AbsRealBin/c++-analyzer";
  DieDiag("'c++-analyzer' does not exist at '$CmdCXX'\n") if(! -e $CmdCXX);
}

Diag("Using '$Clang' for static analysis\n");

SetHtmlEnv(\@ARGV, $HtmlDir);
if ($AnalyzeHeaders) { push @AnalysesToRun,"-analyzer-opt-analyze-headers"; }
if ($AnalyzerStats) { push @AnalysesToRun, '-analyzer-checker=debug.Stats'; }
if ($MaxLoop > 0) { push @AnalysesToRun, "-analyzer-max-loop $MaxLoop"; }

# Delay setting up other environment variables in case we can do true
# interposition.
my $CCC_ANALYZER_ANALYSIS = join ' ',@AnalysesToRun;
my $CCC_ANALYZER_PLUGINS = join ' ',@PluginsToLoad;
my $CCC_ANALYZER_CONFIG = join ' ',@ConfigOptions;
my %Options = (
  'CC' => $Cmd,
  'CXX' => $CmdCXX,
  'CLANG' => $Clang,
  'CLANG_CXX' => $ClangCXX,
  'VERBOSE' => $Verbose,
  'CCC_ANALYZER_ANALYSIS' => $CCC_ANALYZER_ANALYSIS,
  'CCC_ANALYZER_PLUGINS' => $CCC_ANALYZER_PLUGINS,
  'CCC_ANALYZER_CONFIG' => $CCC_ANALYZER_CONFIG,
  'OUTPUT_DIR' => $HtmlDir
);

if (defined $StoreModel) {
  $Options{'CCC_ANALYZER_STORE_MODEL'} = $StoreModel;
}
if (defined $ConstraintsModel) {
  $Options{'CCC_ANALYZER_CONSTRAINTS_MODEL'} = $ConstraintsModel;
}
if (defined $InternalStats) {
  $Options{'CCC_ANALYZER_INTERNAL_STATS'} = 1;
}
if (defined $OutputFormat) {
  $Options{'CCC_ANALYZER_OUTPUT_FORMAT'} = $OutputFormat;
}

# Run the build.
my $ExitStatus = RunBuildCommand(\@ARGV, $IgnoreErrors, $Cmd, $CmdCXX,
                                \%Options);

if (defined $OutputFormat) {
  if ($OutputFormat =~ /plist/) {
    Diag "Analysis run complete.\n";
    Diag "Analysis results (plist files) deposited in '$HtmlDir'\n";
  }
  if ($OutputFormat =~ /html/) {
    # Postprocess the HTML directory.
    my $NumBugs = Postprocess($HtmlDir, $BaseDir, $AnalyzerStats, $KeepEmpty);

    if ($ViewResults and -r "$HtmlDir/index.html") {
      Diag "Analysis run complete.\n";
      Diag "Viewing analysis results in '$HtmlDir' using scan-view.\n";
      my $ScanView = Cwd::realpath("$RealBin/scan-view");
      if (! -x $ScanView) { $ScanView = "scan-view"; }
      exec $ScanView, "$HtmlDir";
    }

    if ($ExitStatusFoundBugs) {
      exit 1 if ($NumBugs > 0);
      exit 0;
    }
  }
}

exit $ExitStatus;