lcov: Fix branch coverage summary

When combining two data files A (without branch coverage data) and B
(with branch coverage data), lcov will incorrectly report no branch
coverage data for the resulting file in program output, even though the
resulting file contains branch coverage data. This only happens when A
is specified first during the add operation.

This is due to a bug in lcov that loses the correctly combined branch
coverage data internally in function brcount_db_combine() when its first
parameter is undefined. Fix this by ensuring that the first parameter is
an empty hash reference instead.

Signed-off-by: Peter Oberparleiter <[email protected]>

Author: oberpar

bin/lcov

@@ -2153,7 +2153,7 @@ sub brcount_to_db($)
 {
 	my ($brcount) = @_;
 	my $line;
-	my $db;
+	my $db = {};
 
 	# Add branches to database
 	foreach $line (keys(%{$brcount})) {