geninfo: Fix gcov version detection for XCode 8.0

The LLVM gcov version included in XCode 8.0 reports its version in a
format that is not understood by geninfo, resulting in the wrong format
of coverage data files being expected. Fix this by reworking gcov
version detection in geninfo to be more robust.

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

Author: oberpar

bin/geninfo

@@ -160,6 +160,8 @@ sub solve_relative_path($$);
 sub read_gcov_header($);
 sub read_gcov_file($);
 sub info(@);
+sub map_llvm_version($);
+sub version_to_str($);
 sub get_gcov_version();
 sub system_no_output($@);
 sub read_config($);
@@ -1901,6 +1903,36 @@ sub read_gcov_file($)
 }
 
 
+# Map LLVM versions to the version of GCC gcov which they emulate.
+
+sub map_llvm_version($)
+{
+	my ($ver) = @_;
+
+	return 0x040200 if ($ver >= 0x030400);
+
+	warn("WARNING: This version of LLVM's gcov is unknown.  ".
+	     "Assuming it emulates GCC gcov version 4.2.\n");
+
+	return 0x040200;
+}
+
+
+# Return a readable version of encoded gcov version.
+
+sub version_to_str($)
+{
+	my ($ver) = @_;
+	my ($a, $b, $c);
+
+	$a = $ver >> 16 & 0xff;
+	$b = $ver >> 8 & 0xff;
+	$c = $ver & 0xff;
+
+	return "$a.$b.$c";
+}
+
+
 #
 # Get the GCOV tool version. Return an integer number which represents the
 # GCOV version. Version numbers can be compared using standard integer
@@ -1912,58 +1944,48 @@ sub get_gcov_version()
 	local *HANDLE;
 	my $version_string;
 	my $result;
-	my $pipe_next_line;
+	my ($a, $b, $c) = (4, 2, 0);	# Fallback version
+
+	# Examples for gcov version output:
+	#
+	# gcov (GCC) 4.4.7 20120313 (Red Hat 4.4.7-3)
+	#
+	# gcov (crosstool-NG 1.18.0) 4.7.2
+	#
+	# LLVM (http://llvm.org/):
+	#   LLVM version 3.4svn
+	#
+	# Apple LLVM version 8.0.0 (clang-800.0.38)
+	#       Optimized build.
+	#       Default target: x86_64-apple-darwin16.0.0
+	#       Host CPU: haswell
 
 	open(GCOV_PIPE, "-|", "$gcov_tool --version")
 		or die("ERROR: cannot retrieve gcov version!\n");
+	local $/;
 	$version_string = <GCOV_PIPE>;
-	# LLVM gcov keeps version information on the second line.
-	# For example, gcov --version yields:
-	# LLVM (http://llvm.org/):
-	#   LLVM version 3.4svn
-
-	$pipe_next_line = <GCOV_PIPE>;	
-	# In case version information is on first line.
-	# For example, with Xcode 7.0 gcov --version yields:
-	# Apple LLVM 7.0.0 (clang-700.0.65)
-
-	$version_string = $pipe_next_line if ($pipe_next_line && $version_string =~ /LLVM/);
 	close(GCOV_PIPE);
 
-	# Remove version information in parenthesis to cope with the following:
-	# - gcov (GCC) 4.4.7 20120313 (Red Hat 4.4.7-3)
-	# - gcov (crosstool-NG 1.18.0) 4.7.2
+	# Remove all bracketed information
 	$version_string =~ s/\([^\)]*\)//g;
 
-	$result = 0;
-	if ($version_string =~ /(\d+)\.(\d+)(\.(\d+))?/)
-	{
-		if (defined($4))
-		{
-			info("Found gcov version: $1.$2.$4\n");
-			$result = $1 << 16 | $2 << 8 | $4;
-		}
-		else
-		{
-			info("Found gcov version: $1.$2\n");
-			$result = $1 << 16 | $2 << 8;
-		}
+	if ($version_string =~ /(\d+)\.(\d+)(\.(\d+))?/) {
+		($a, $b, $c) = ($1, $2, $4);
+		$c = 0 if (!defined($c));
+	} else {
+		warn("WARNING: cannot determine gcov version - ".
+		     "assuming $a.$b.$c\n");
 	}
-	if ($version_string =~ /LLVM/)
-	{
-		# Map LLVM versions to the version of GCC gcov which
-		# they emulate
-		if ($result >= 0x030400)
-		{
-			info("Found LLVM gcov version 3.4, which emulates gcov version 4.2\n");
-			$result = 0x040200;
-		}
-		else
-		{
-			warn("This version of LLVM's gcov is unknown.  Assuming it emulates GCC gcov version 4.2.\n");
-			$result = 0x040200;
-		}
+	$result = $a << 16 | $b << 8 | $c;
+
+	if ($version_string =~ /LLVM/) {
+		$result = map_llvm_version($result);
+		info("Found LLVM gcov version $a.$b.$c, which emulates gcov ".
+		     "version ".version_to_str($result)."\n");
+	} else {
+		info("Found gcov version: ".version_to_str($result)."\n");
 	}
+
 	return ($result, $version_string);
 }