checkpatch: improve runtime execution speed a little

checkpatch repeatedly uses a runtime minimum version check that validates
the minimum perl version required for a regex match by using a "$^V ge
5.10.0" runtime string match.

Only perform that minimum version test once and store the result to reduce
string matching time.

This reduces runtime execution time for patches or files with high line
counts.

An example runtime improvement:

new: $ time ./scripts/checkpatch.pl -f drivers/net/ethernet/intel/i40e/i40e_main.c > /dev/null

real	0m11.856s
user	0m11.831s
sys	0m0.025s

old: $ time ./scripts/checkpatch.pl -f drivers/net/ethernet/intel/i40e/i40e_main.c > /dev/null

real	0m13.330s
user	0m13.282s
sys	0m0.049s

Link: http://lkml.kernel.org/r/db21aa9703833bad65ab70cc4e8a78da5b399138.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 33 insertions, 33 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index f2e00dc0ae89..0f9788ab988b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -240,11 +240,11 @@ $check_orig = $check;
 
 my $exit = 0;
 
+my $perl_version_ok = 1;
 if ($^V && $^V lt $minimum_perl_version) {
+        $perl_version_ok = 0;
         printf "$P: requires at least perl version %vd\n", $minimum_perl_version;
-        if (!$ignore_perl_version) {
-                exit(1);
-        }
+        exit(1) if (!$ignore_perl_version);
 }
 
 #if no filenames are given, push '-' to read patch from stdin
@@ -1026,11 +1026,11 @@ if (!$quiet) {
         hash_show_words(\%use_type, "Used");
         hash_show_words(\%ignore_type, "Ignored");
 
-        if ($^V lt 5.10.0) {
+        if (!$perl_version_ok) {
                 print << "EOM"
 
 NOTE: perl $^V is not modern enough to detect all possible issues.
-      An upgrade to at least perl v5.10.0 is suggested.
+      An upgrade to at least perl $minimum_perl_version is suggested.
 EOM
         }
         if ($exit) {
@@ -3079,7 +3079,7 @@ sub process {
                 }
 
 # check indentation starts on a tab stop
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     $sline =~ /^\+\t+( +)(?:$c90_Keywords\b|\{\s*$|\}\s*(?:else\b|while\b|\s*$)|$Declare\s*$Ident\s*[;=])/) {
                         my $indent = length($1);
                         if ($indent % 8) {
@@ -3092,7 +3092,7 @@ sub process {
                 }
 
 # check multi-line statement indentation matches previous line
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     $prevline =~ /^\+([ \t]*)((?:$c90_Keywords(?:\s+if)\s*)|(?:$Declare\s*)?(?:$Ident|\(\s*\*\s*$Ident\s*\))\s*|(?:\*\s*)*$Lval\s*=\s*$Ident\s*)\(.*(\&\&|\|\||,)\s*$/) {
                         $prevline =~ /^\+(\t*)(.*)$/;
                         my $oldindent = $1;
@@ -3967,7 +3967,7 @@ sub process {
 
 # function brace can't be on same line, except for #defines of do while,
 # or if closed on same line
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     $sline =~ /$Type\s*$Ident\s*$balanced_parens\s*\{/ &&
                     $sline !~ /\#\s*define\b.*do\s*\{/ &&
                     $sline !~ /}/) {
@@ -4578,7 +4578,7 @@ sub process {
 # check for unnecessary parentheses around comparisons in if uses
 # when !drivers/staging or command-line uses --strict
                 if (($realfile !~ m@^(?:drivers/staging/)@ || $check_orig) &&
-                    $^V && $^V ge 5.10.0 && defined($stat) &&
+                    $perl_version_ok && defined($stat) &&
                     $stat =~ /(^.\s*if\s*($balanced_parens))/) {
                         my $if_stat = $1;
                         my $test = substr($2, 1, -1);
@@ -4615,7 +4615,7 @@ sub process {
 # return is not a function
                 if (defined($stat) && $stat =~ /^.\s*return(\s*)\(/s) {
                         my $spacing = $1;
-                        if ($^V && $^V ge 5.10.0 &&
+                        if ($perl_version_ok &&
                             $stat =~ /^.\s*return\s*($balanced_parens)\s*;\s*$/) {
                                 my $value = $1;
                                 $value = deparenthesize($value);
@@ -4642,7 +4642,7 @@ sub process {
                }
 
 # if statements using unnecessary parentheses - ie: if ((foo == bar))
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     $line =~ /\bif\s*((?:\(\s*){2,})/) {
                         my $openparens = $1;
                         my $count = $openparens =~ tr@\(@\(@;
@@ -4659,7 +4659,7 @@ sub process {
 #       avoid cases like "foo + BAR < baz"
 #       only fix matches surrounded by parentheses to avoid incorrect
 #       conversions like "FOO < baz() + 5" being "misfixed" to "baz() > FOO + 5"
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     $line =~ /^\+(.*)\b($Constant|[A-Z_][A-Z0-9_]*)\s*($Compare)\s*($LvalOrFunc)/) {
                         my $lead = $1;
                         my $const = $2;
@@ -5084,7 +5084,7 @@ sub process {
 # do {} while (0) macro tests:
 # single-statement macros do not need to be enclosed in do while (0) loop,
 # macro should not end with a semicolon
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     $realfile !~ m@/vmlinux.lds.h$@ &&
                     $line =~ /^.\s*\#\s*define\s+$Ident(\()?/) {
                         my $ln = $linenr;
@@ -5460,7 +5460,7 @@ sub process {
                 }
 
 # check for mask then right shift without a parentheses
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     $line =~ /$LvalOrFunc\s*\&\s*($LvalOrFunc)\s*>>/ &&
                     $4 !~ /^\&/) { # $LvalOrFunc may be &foo, ignore if so
                         WARN("MASK_THEN_SHIFT",
@@ -5468,7 +5468,7 @@ sub process {
                 }
 
 # check for pointer comparisons to NULL
-                if ($^V && $^V ge 5.10.0) {
+                if ($perl_version_ok) {
                         while ($line =~ /\b$LvalOrFunc\s*(==|\!=)\s*NULL\b/g) {
                                 my $val = $1;
                                 my $equal = "!";
@@ -5740,7 +5740,7 @@ sub process {
                 }
 
 # Check for __attribute__ weak, or __weak declarations (may have link issues)
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     $line =~ /(?:$Declare|$DeclareMisordered)\s*$Ident\s*$balanced_parens\s*(?:$Attribute)?\s*;/ &&
                     ($line =~ /\b__attribute__\s*\(\s*\(.*\bweak\b/ ||
                      $line =~ /\b__weak\b/)) {
@@ -5822,7 +5822,7 @@ sub process {
                 }
 
 # check for vsprintf extension %p<foo> misuses
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     defined $stat &&
                     $stat =~ /^\+(?![^\{]*\{\s*).*\b(\w+)\s*\(.*$String\s*,/s &&
                     $1 !~ /^_*volatile_*$/) {
@@ -5869,7 +5869,7 @@ sub process {
                 }
 
 # Check for misused memsets
-                if ($^V && $^V ge 5.10.0 &&
+                if ($perl_version_ok &&
                     defined $stat &&
                     $stat =~ /^\+(?:.*?)\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*$FuncArg\s*\)/) {
 
@@ -5887,7 +5887,7 @@ sub process {
                 }
 
 # Check for memcpy(foo, bar, ETH_ALEN) that could be ether_addr_copy(foo, bar)
-#               if ($^V && $^V ge 5.10.0 &&
+#               if ($perl_version_ok &&