geninfo: add exclude marker for branch coverage

Sometimes it can be helpful to generally use branch coverage but to
disable it for some lines of code without excluding the line or function
coverage too.

For example if you make heavily use of assertions in your code (which is
generally a good idea) you will see that for each 'assert(...)' exist
one branch which is taken and one that is not. Similarly you can see the
same phenomenon for 'delete' in C++ code.

If you use the 'LCOV_EXCL_LINE' marker in such a situation both of these
branches will be omitted from the output. But in doing so, you loose the
ability to determine if this peace of code is genuine 'dead code' or not
because the line coverage is omitted too.

The newly introduces 'LCOV_EXCL_BR_LINE', 'LCOV_EXCL_BR_START' and
'LCOV_EXCL_BR_STOP' marker address this problem. The usage is similar to
the 'LCOV_EXCL_LINE' etc. markers.

Signed-off-by: Sebastian Stigler <[email protected]>

Author: sebastianstigler

bin/geninfo

@@ -61,7 +61,7 @@ if( $^O eq "msys" )
 }
 
 # Constants
-our $lcov_version	= 'LCOV version 1.11 pre (CVS $Revision: 1.123 $)';
+our $lcov_version	= 'LCOV version 1.11 pre (CVS $Revision: 1.124 $)';
 our $lcov_url		= "http://ltp.sourceforge.net/coverage/lcov.php";
 our $gcov_tool		= "gcov";
 our $tool_name		= basename($0);
@@ -88,6 +88,11 @@ our $EXCL_START = "LCOV_EXCL_START";
 our $EXCL_STOP = "LCOV_EXCL_STOP";
 our $EXCL_LINE = "LCOV_EXCL_LINE";
 
+# Marker to exclude branch coverage but keep function and line coveage
+our $EXCL_BR_START = "LCOV_EXCL_BR_START";
+our $EXCL_BR_STOP = "LCOV_EXCL_BR_STOP";
+our $EXCL_BR_LINE = "LCOV_EXCL_BR_LINE";
+
 # Compatibility mode values
 our $COMPAT_VALUE_OFF	= 0;
 our $COMPAT_VALUE_ON	= 1;
@@ -1667,6 +1672,8 @@ sub read_gcov_file($)
 	my $number;
 	my $exclude_flag = 0;
 	my $exclude_line = 0;
+	my $exclude_br_flag = 0;
+	my $exclude_branch = 0;
 	my $last_block = $UNNAMED_BLOCK;
 	my $last_line = 0;
 	local *INPUT;
@@ -1693,11 +1700,13 @@ sub read_gcov_file($)
 			if (/^branch\s+(\d+)\s+taken\s+=\s+(\d+)/) {
 				next if (!$br_coverage);
 				next if ($exclude_line);
+				next if ($exclude_branch);
 				$branches = br_gvec_push($branches, $last_line,
 						$last_block, $1, $2);
 			} elsif (/^branch\s+(\d+)\s+never\s+executed/) {
 				next if (!$br_coverage);
 				next if ($exclude_line);
+				next if ($exclude_branch);
 				$branches = br_gvec_push($branches, $last_line,
 						$last_block, $1, '-');
 			}
@@ -1721,6 +1730,19 @@ sub read_gcov_file($)
 						$exclude_line = 0;
 					}
 				}
+				# Check for exclusion markers (branch exclude)
+				if (!$no_markers) {
+					if (/$EXCL_BR_STOP/) {
+						$exclude_br_flag = 0;
+					} elsif (/$EXCL_BR_START/) {
+						$exclude_br_flag = 1;
+					}
+					if (/$EXCL_BR_LINE/ || $exclude_br_flag) {
+						$exclude_branch = 1;
+					} else {
+						$exclude_branch = 0;
+					}
+				}
 				# Source code execution data
 				if (/^\t\t(.*)$/)
 				{
@@ -1766,11 +1788,13 @@ sub read_gcov_file($)
 			} elsif (/^branch\s+(\d+)\s+taken\s+(\d+)/) {
 				next if (!$br_coverage);
 				next if ($exclude_line);
+				next if ($exclude_branch);
 				$branches = br_gvec_push($branches, $last_line,
 						$last_block, $1, $2);
 			} elsif (/^branch\s+(\d+)\s+never\s+executed/) {
 				next if (!$br_coverage);
 				next if ($exclude_line);
+				next if ($exclude_branch);
 				$branches = br_gvec_push($branches, $last_line,
 						$last_block, $1, '-');
 			}
@@ -1805,6 +1829,20 @@ sub read_gcov_file($)
 						$exclude_line = 0;
 					}
 				}
+				# Check for exclusion markers (branch exclude)
+				if (!$no_markers) {
+					if (/$EXCL_BR_STOP/) {
+						$exclude_br_flag = 0;
+					} elsif (/$EXCL_BR_START/) {
+						$exclude_br_flag = 1;
+					}
+					if (/$EXCL_BR_LINE/ || $exclude_br_flag) {
+						$exclude_branch = 1;
+					} else {
+						$exclude_branch = 0;
+					}
+				}
+
 				# <exec count>:<line number>:<source code>
 				if ($line eq "0")
 				{
@@ -1837,7 +1875,7 @@ sub read_gcov_file($)
 	}
 
 	close(INPUT);
-	if ($exclude_flag) {
+	if ($exclude_flag || $exclude_br_flag) {
 		warn("WARNING: unterminated exclusion section in $filename\n");
 	}
 	return(\@result, $branches, \@functions);

man/geninfo.1

@@ -74,8 +74,10 @@ so that there is usually no need to call it directly.
 .B Exclusion markers
 
 To exclude specific lines of code from a tracefile, you can add exclusion
-markers to the source code. Exclusion markers are keywords which can for
-example be added in the form of a comment.
+markers to the source code. Additionally you can exclude specific branches from
+branch coverage without excluding the involved lines from line and function
+coverage. Exclusion markers are keywords which can for example be added in the
+form of a comment.
 
 The following markers are recognized by geninfo:
 
@@ -96,6 +98,23 @@ Marks the end of an excluded section. The current line not part of this
 section.
 .RE
 .br
+LCOV_EXCL_BR_LINE
+.RS
+Lines containing this marker will be excluded from branch coverage.
+.br
+.RE
+LCOV_EXCL_BR_START
+.RS
+Marks the beginning of a section which is excluded from branch coverage. The
+current line is part of this section.
+.br
+.RE
+LCOV_EXCL_BR_STOP
+.RS
+Marks the end of a section which is excluded from branch coverage. The current
+line not part of this section.
+.RE
+.br
 
 .SH OPTIONS