checkpatch: add some --strict coding style checks

Argument alignment across multiple lines should match the open
parenthesis.

Logical continuations should be at the end of the previous line, not the
start of a new line.

These are not required by CodingStyle so make the tests active only when
using --strict.

Improved by some examples from Bruce Allen.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: "Bruce W. Allen" <bruce.w.allan@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 84 insertions, 10 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 89d24b3ea438..308e4015bd8e 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -330,10 +330,15 @@ sub build_types {
 }
 build_types();
 
-our $match_balanced_parentheses = qr/(\((?:[^\(\)]+|(-1))*\))/;
 
 our $Typecast   = qr{\s*(\(\s*$NonptrType\s*\)){0,1}\s*};
-our $LvalOrFunc = qr{($Lval)\s*($match_balanced_parentheses{0,1})\s*};
+
+# Using $balanced_parens, $LvalOrFunc, or $FuncArg
+# requires at least perl version v5.10.0
+# Any use must be runtime checked with $^V
+
+our $balanced_parens = qr/(\((?:[^\(\)]++|(?-1))*\))/;
+our $LvalOrFunc = qr{($Lval)\s*($balanced_parens{0,1})\s*};
 our $FuncArg = qr{$Typecast{0,1}($LvalOrFunc|$Constant)};
 
 sub deparenthesize {
@@ -1330,6 +1335,36 @@ sub check_absolute_file {
         }
 }
 
+sub pos_last_openparen {
+        my ($line) = @_;
+
+        my $pos = 0;
+
+        my $opens = $line =~ tr/\(/\(/;
+        my $closes = $line =~ tr/\)/\)/;
+
+        my $last_openparen = 0;
+
+        if (($opens == 0) || ($closes >= $opens)) {
+                return -1;
+        }
+
+        my $len = length($line);
+
+        for ($pos = 0; $pos < $len; $pos++) {
+                my $string = substr($line, $pos);
+                if ($string =~ /^($FuncArg|$balanced_parens)/) {
+                        $pos += length($1) - 1;
+                } elsif (substr($line, $pos, 1) eq '(') {
+                        $last_openparen = $pos;
+                } elsif (index($string, '(') == -1) {
+                        last;
+                }
+        }
+
+        return $last_openparen + 1;
+}
+
 sub process {
         my $filename = shift;
 
@@ -1783,6 +1818,37 @@ sub process {
                              "please, no space before tabs\n" . $herevet);
                 }
 
+# check for && or || at the start of a line
+                if ($rawline =~ /^\+\s*(&&|\|\|)/) {
+                        CHK("LOGICAL_CONTINUATIONS",
+                            "Logical continuations should be on the previous line\n" . $hereprev);
+                }
+
+# check multi-line statement indentation matches previous line
+                if ($^V && $^V ge 5.10.0 &&
+                    $prevline =~ /^\+(\t*)(if \(|$Ident\().*(\&\&|\|\||,)\s*$/) {
+                        $prevline =~ /^\+(\t*)(.*)$/;
+                        my $oldindent = $1;
+                        my $rest = $2;
+
+                        my $pos = pos_last_openparen($rest);
+                        if ($pos >= 0) {
+                                $line =~ /^\+([ \t]*)/;
+                                my $newindent = $1;
+
+                                my $goodtabindent = $oldindent .
+                                        "\t" x ($pos / 8) .
+                                        " "  x ($pos % 8);
+                                my $goodspaceindent = $oldindent . " "  x $pos;
+
+                                if ($newindent ne $goodtabindent &&
+                                    $newindent ne $goodspaceindent) {
+                                        CHK("PARENTHESIS_ALIGNMENT",
+                                            "Alignment should match open parenthesis\n" . $hereprev);
+                                }
+                        }
+                }
+
 # check for spaces at the beginning of a line.
 # Exceptions:
 #  1) within comments
@@ -3142,12 +3208,13 @@ sub process {
                 }
 
 # Check for misused memsets
-                if (defined $stat &&
+                if ($^V && $^V ge 5.10.0 &&
+                    defined $stat &&
                     $stat =~ /^\+(?:.*?)\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*$FuncArg\s*\)/s) {
 
                         my $ms_addr = $2;
-                        my $ms_val = $8;
-                        my $ms_size = $14;
+                        my $ms_val = $7;
+                        my $ms_size = $12;
 
                         if ($ms_size =~ /^(0x|)0$/i) {
                                 ERROR("MEMSET",
@@ -3159,17 +3226,18 @@ sub process {
                 }
 
 # typecasts on min/max could be min_t/max_t
-                if (defined $stat &&
+                if ($^V && $^V ge 5.10.0 &&
+                    defined $stat &&
                     $stat =~ /^\+(?:.*?)\b(min|max)\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\)/) {
-                        if (defined $2 || defined $8) {
+                        if (defined $2 || defined $7) {
                                 my $call = $1;
                                 my $cast1 = deparenthesize($2);
                                 my $arg1 = $3;
-                                my $cast2 = deparenthesize($8);
-                                my $arg2 = $9;
+                                my $cast2 = deparenthesize($7);
+                                my $arg2 = $8;
                                 my $cast;
 
-                                if ($cast1 ne "" && $cast2 ne "") {
+                                if ($cast1 ne "" && $cast2 ne "" && $cast1 ne $cast2) {
                                         $cast = "$cast1 or $cast2";
                                 } elsif ($cast1 ne "") {
                                         $cast = $cast1;
@@ -3391,6 +3459,12 @@ sub process {
         }
 
         if ($quiet == 0) {
+
+                if ($^V lt 5.10.0) {
+                        print("NOTE: perl $^V is not modern enough to detect all possible issues.\n");
+                        print("An upgrade to at least perl v5.10.0 is suggested.\n\n");
+                }
+
                 # If there were whitespace errors which cleanpatch can fix
                 # then suggest that.
                 if ($rpt_cleaners) {