checkpatch: track #ifdef/#else/#endif when tracking blocks

When picking up a complete statement or block for analysis we cannot
simply track open/close/etc parenthesis we must take into account
preprocessor section boundaries.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 67b0c9faa32d..906624c0e9e6 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -405,6 +405,7 @@ sub ctx_statement_block {
 
         my $type = '';
         my $level = 0;
+        my @stack = ([$type, $level]);
         my $p;
         my $c;
         my $len = 0;
@@ -436,6 +437,16 @@ sub ctx_statement_block {
                 $remainder = substr($blk, $off);
 
                 #warn "CSB: c<$c> type<$type> level<$level> remainder<$remainder> coff_set<$coff_set>\n";
+
+                # Handle nested #if/#else.
+                if ($remainder =~ /^#\s*(?:ifndef|ifdef|if)\s/) {
+                        push(@stack, [ $type, $level ]);
+                } elsif ($remainder =~ /^#\s*(?:else|elif)\b/) {
+                        ($type, $level) = @{$stack[$#stack - 1]};
+                } elsif ($remainder =~ /^#\s*endif\b/) {
+                        ($type, $level) = @{pop(@stack)};
+                }
+
                 # Statement ends at the ';' or a close '}' at the
                 # outermost level.
                 if ($level == 0 && $c eq ';') {
@@ -582,11 +593,22 @@ sub ctx_block_get {
         my @res = ();
 
         my $level = 0;
+        my @stack = ($level);
         for ($line = $start; $remain > 0; $line++) {
                 next if ($rawlines[$line] =~ /^-/);
                 $remain--;
 
                 $blk .= $rawlines[$line];
+
+                # Handle nested #if/#else.
+                if ($rawlines[$line] =~ /^.\s*#\s*(?:ifndef|ifdef|if)\s/) {
+                        push(@stack, $level);
+                } elsif ($rawlines[$line] =~ /^.\s*#\s*(?:else|elif)\b/) {
+                        $level = $stack[$#stack - 1];
+                } elsif ($rawlines[$line] =~ /^.\s*#\s*endif\b/) {
+                        $level = pop(@stack);
+                }
+
                 foreach my $c (split(//, $rawlines[$line])) {
                         ##print "C<$c>L<$level><$open$close>O<$off>\n";
                         if ($off > 0) {