From f74bd1942e04a0cedd1e9c8b331141e75add49c0 Mon Sep 17 00:00:00 2001
From: Andy Whitcroft <apw@canonical.com>
Date: Tue, 10 Jan 2012 15:09:54 -0800
Subject: [PATCH] checkpatch: correctly track the end of preprocessor commands
 in context

When looking for a statement we currently run on through preprocessor
commands.  This means that a header file with just definitions is parsed
over and over again combining all of the lines from the current line to
the end of file leading to severe performance issues.

Fix up context accumulation to track preprocessor commands and stop when
reaching the end of them.  At the same time vastly simplify the #define
handling.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 scripts/checkpatch.pl | 90 +++++++++++++++++++------------------------
 1 file changed, 39 insertions(+), 51 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e94626ca77cf..06e22caa5692 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -676,6 +676,10 @@ sub ctx_statement_block {
 			if ($off >= $len) {
 				last;
 			}
+			if ($level == 0 && substr($blk, $off) =~ /^.\s*#\s*define/) {
+				$level++;
+				$type = '#';
+			}
 		}
 		$p = $c;
 		$c = substr($blk, $off, 1);
@@ -738,6 +742,13 @@ sub ctx_statement_block {
 				last;
 			}
 		}
+		# Preprocessor commands end at the newline unless escaped.
+		if ($type eq '#' && $c eq "\n" && $p ne "\\") {
+			$level--;
+			$type = '';
+			$off++;
+			last;
+		}
 		$off++;
 	}
 	# We are truly at the end, so shuffle to the next line.
@@ -1801,6 +1812,8 @@ sub process {
 			$stat =~ s/\n./\n /g;
 			$cond =~ s/\n./\n /g;
 
+#print "stat<$stat>\n";
+
 			# Find the real next line.
 			$realline_next = $line_nr_next;
 			if (defined $realline_next &&
@@ -2781,47 +2794,13 @@ sub process {
 			my $cnt = $realcnt;
 			my ($off, $dstat, $dcond, $rest);
 			my $ctx = '';
-
-			my $args = defined($1);
-
-			# Find the end of the macro and limit our statement
-			# search to that.
-			while ($cnt > 0 && defined $lines[$ln - 1] &&
-				$lines[$ln - 1] =~ /^(?:-|..*\\$)/)
-			{
-				$ctx .= $rawlines[$ln - 1] . "\n";
-				$cnt-- if ($lines[$ln - 1] !~ /^-/);
-				$ln++;
-			}
-			$ctx .= $rawlines[$ln - 1];
-
 			($dstat, $dcond, $ln, $cnt, $off) =
-				ctx_statement_block($linenr, $ln - $linenr + 1, 0);
+				ctx_statement_block($linenr, $realcnt, 0);
+			$ctx = $dstat;
 			#print "dstat<$dstat> dcond<$dcond> cnt<$cnt> off<$off>\n";
 			#print "LINE<$lines[$ln-1]> len<" . length($lines[$ln-1]) . "\n";
 
-			# Extract the remainder of the define (if any) and
-			# rip off surrounding spaces, and trailing \'s.
-			$rest = '';
-			while ($off != 0 || ($cnt > 0 && $rest =~ /\\\s*$/)) {
-				#print "ADDING cnt<$cnt> $off <" . substr($lines[$ln - 1], $off) . "> rest<$rest>\n";
-				if ($off != 0 || $lines[$ln - 1] !~ /^-/) {
-					$rest .= substr($lines[$ln - 1], $off) . "\n";
-					$cnt--;
-				}
-				$ln++;
-				$off = 0;
-			}
-			$rest =~ s/\\\n.//g;
-			$rest =~ s/^\s*//s;
-			$rest =~ s/\s*$//s;
-
-			# Clean up the original statement.
-			if ($args) {
-				substr($dstat, 0, length($dcond), '');
-			} else {
-				$dstat =~ s/^.\s*\#\s*define\s+$Ident\s*//;
-			}
+			$dstat =~ s/^.\s*\#\s*define\s+$Ident(?:\([^\)]*\))?\s*//;
 			$dstat =~ s/$;//g;
 			$dstat =~ s/\\\n.//g;
 			$dstat =~ s/^\s*//s;
@@ -2847,23 +2826,32 @@ sub process {
 				^\"|\"$
 			}x;
 			#print "REST<$rest> dstat<$dstat> ctx<$ctx>\n";
-			if ($rest ne '' && $rest ne ',') {
-				if ($rest !~ /while\s*\(/ &&
-				    $dstat !~ /$exceptions/)
-				{
-					ERROR("MULTISTATEMENT_MACRO_USE_DO_WHILE",
-					      "Macros with multiple statements should be enclosed in a do - while loop\n" . "$here\n$ctx\n");
+			if ($dstat ne '' &&
+			    $dstat !~ /^(?:$Ident|-?$Constant),$/ &&			# 10, // foo(),
+			    $dstat !~ /^(?:$Ident|-?$Constant);$/ &&			# foo();
+			    $dstat !~ /^(?:$Ident|-?$Constant)$/ &&			# 10 // foo()
+			    $dstat !~ /$exceptions/ &&
+			    $dstat !~ /^\.$Ident\s*=/ &&				# .foo =
+			    $dstat !~ /^do\s*$Constant\s*while\s*$Constant;$/ &&	# do {...} while (...);
+			    $dstat !~ /^for\s*$Constant$/ &&				# for (...)
+			    $dstat !~ /^for\s*$Constant\s+(?:$Ident|-?$Constant)$/ &&	# for (...) bar()
+			    $dstat !~ /^do\s*{/ &&					# do {...
+			    $dstat !~ /^\({/)						# ({...
+			{
+				$ctx =~ s/\n*$//;
+				my $herectx = $here . "\n";
+				my $cnt = statement_rawlines($ctx);
+
+				for (my $n = 0; $n < $cnt; $n++) {
+					$herectx .= raw_line($linenr, $n) . "\n";
 				}
 
-			} elsif ($ctx !~ /;/) {
-				if ($dstat ne '' &&
-				    $dstat !~ /^(?:$Ident|-?$Constant)$/ &&
-				    $dstat !~ /$exceptions/ &&
-				    $dstat !~ /^\.$Ident\s*=/ &&
-				    $dstat =~ /$Operators/)
-				{
+				if ($dstat =~ /;/) {
+					ERROR("MULTISTATEMENT_MACRO_USE_DO_WHILE",
+					      "Macros with multiple statements should be enclosed in a do - while loop\n" . "$herectx");
+				} else {
 					ERROR("COMPLEX_MACRO",
-					      "Macros with complex values should be enclosed in parenthesis\n" . "$here\n$ctx\n");
+					      "Macros with complex values should be enclosed in parenthesis\n" . "$herectx");
 				}
 			}
 		}