Add option to filter blank lines 'aggressively': ignore them regardless

of whether their 'hit' count is zero or not.
This may be useful in LLVM-generated coverage data which tends to
contain large number of these - distorting statistics.

Signed-off-by:  Henry Cox <[email protected]>

Author: henry2cox

lcovrc

@@ -82,6 +82,10 @@ max_message_count = 100
 # if nonzero, bitwise operators '|', '&', '~' indicate conditional expressions
 #filter_bitwise_conditional = 1
 
+# if nonzero, '--filter blank' is applied to blank lines, regardless
+# of their hit count
+#filter_blank_aggressive = 1
+
 # Width of line coverage field in source code view
 genhtml_line_field_width = 12
 

lib/lcovutil.pm

@@ -66,6 +66,7 @@ our @EXPORT_OK = qw($tool_name $tool_dir $lcov_version $lcov_url
      $exclude_exception_branch
      $derive_function_end_line $derive_function_end_line_all_files
      $trivial_function_threshold
+     $filter_blank_aggressive
 
      $lcov_filter_parallel $lcov_filter_chunk_size
 
@@ -312,6 +313,8 @@ our $source_filter_lookahead = 10;
 # by default, don't treat expressions containing bitwise operators '|', '&', '~'
 #   as conditional in bogus branch filtering
 our $source_filter_bitwise_are_conditional = 0;
+# filter out blank lines whether they are hit or not
+our $filter_blank_aggressive = 0;
 
 our %dark_palette = ('COLOR_00' => "e4e4e4",
                      'COLOR_01' => "58a6ff",
@@ -1064,11 +1067,12 @@ my %rc_common = (
              "filter_lookahead"       => \$lcovutil::source_filter_lookahead,
              "filter_bitwise_conditional" =>
         \$lcovutil::source_filter_bitwise_are_conditional,
-             "profile"           => \$lcovutil::profile,
-             "parallel"          => \$lcovutil::maxParallelism,
-             "memory"            => \$lcovutil::maxMemory,
-             "memory_percentage" => \$lcovutil::memoryPercentage,
-             'source_directory'  => \@rc_source_directories,
+             'filter_blank_aggressive' => \$filter_blank_aggressive,
+             "profile"                 => \$lcovutil::profile,
+             "parallel"                => \$lcovutil::maxParallelism,
+             "memory"                  => \$lcovutil::maxMemory,
+             "memory_percentage"       => \$lcovutil::memoryPercentage,
+             'source_directory'        => \@rc_source_directories,
 
              "no_exception_branch"   => \$lcovutil::exclude_exception_branch,
              'filter'                => \@rc_filter,
@@ -5774,7 +5778,9 @@ sub _filterFile
                 unless $outOfRange ||
                 $excluded;
             my $isBlank =
-                ($blank_histogram && $l_hit == 0 && $srcReader->isBlank($line))
+                ($blank_histogram &&
+                 ($lcovutil::filter_blank_aggressive || $l_hit == 0) &&
+                 $srcReader->isBlank($line))
                 unless $outOfRange ||
                 $excluded;
             next

man/genhtml.1

@@ -1934,6 +1934,10 @@ These lines seem to appear and disappear in gcov output - and cause differential
 
 .IP blank: 3
 ignore lines which contain only whitespace (or whitespace + comments) whose 'hit' count is zero.  These appear to be a 'gcov' artifact related to compiler-generated code - such as exception handlers and destructor calls at the end of scope - and can confuse differential coverage criteria.
+.br
+If lcovrc option
+.I filter_blank_aggressive = 1
+is enabled, then blank lines will be ignored whether their 'hit' count is zero or not.  Aggressive filtering may be useful in LLVM-generated coverage data, which tends to include large numbers of such lines.
 .PP
 
 .IP directive: 3

man/lcovrc.5

@@ -216,6 +216,14 @@ max_message_count = 100
 .br
 #filter_bitwise_conditional = 1
 .br
+.br
+# if nonzero, '--filter blank' is applied to blank lines, regardless
+.br
+# of their hit count
+.br
+#filter_blank_aggressive = 1
+.br
+.br
 
 # Width of line coverage field in source code view
 .br
@@ -868,6 +876,23 @@ This option is used by genhtml and lcov.
 
 .PP
 
+.BR filter_blank_aggressive " ="
+.IR 0|1
+.IP
+If set to non-zero value, then blank source lines will be ignored whether
+or not their 'hit' count is zero.
+See the
+.I \-\-filter blank
+section in man
+.B genhtml(1).
+.br
+
+If not specified, the default set is 0 (filter blank lines only if they are not hit).
+.br
+There is no command line option equivalent.
+
+.PP
+
 .BR ignore_errors " ="
 .IR message_type(,message_type)*
 .IP