Re: [PATCH] checkpatch: Add a --strict test for macro argument reuse and precedence

[Joe Perches]

On Sat, 2016-09-03 at 15:20 -0700, Joe Perches wrote:
> Add a test for reuse of macro arguments to highlight any possible
> side-effects from this reuse.
> 
> Avoid this check on token name pasting and when the
> argument is used in a typeof or a __builtin.
> 
> Add a test for macro arguents that have leading or trailing operators
> where the argument isn't parenthesized to avoid possible precedence
> issues.
> 
> These tests are noisy so make them --strict.

This should have been RFC.  Please do not apply this.

These tests are not just noisy, some false positives it
reports are just silly.

Re: [PATCH] checkpatch: Add a --strict test for macro argument reuse and precedence

[Joe Perches]

On Sat, 2016-09-03 at 15:20 -0700, Joe Perches wrote:
> Add a test for reuse of macro arguments to highlight any possible
> side-effects from this reuse.
> 
> Avoid this check on token name pasting and when the
> argument is used in a typeof or a __builtin.
> 
> Add a test for macro arguents that have leading or trailing operators
> where the argument isn't parenthesized to avoid possible precedence
> issues.
> 
> These tests are noisy so make them --strict.

This should have been RFC.  Please do not apply this.

These tests are not just noisy, some false positives it
reports are just silly.

[PATCH] checkpatch: Add a --strict test for macro argument reuse and precedence

[Joe Perches]

Add a test for reuse of macro arguments to highlight any possible
side-effects from this reuse.

Avoid this check on token name pasting and when the
argument is used in a typeof or a __builtin.

Add a test for macro arguents that have leading or trailing operators
where the argument isn't parenthesized to avoid possible precedence
issues.

These tests are noisy so make them --strict.

Signed-off-by: Joe Perches 
---

This is a slight expansion of a patch I sent a few years back.

https://lkml.org/lkml/2012/11/6/151

This one at least runs.

Maybe it's useful to find some of the possible macro misuses,
but it is _very_ noisy.

 scripts/checkpatch.pl | 47 +++
 1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 8946904..921155f 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4714,7 +4714,17 @@ sub process {
$has_flow_statement = 1 if ($ctx =~ 
/\b(goto|return)\b/);
$has_arg_concat = 1 if ($ctx =~ /\#\#/ && $ctx !~ 
/\#\#\s*(?:__VA_ARGS__|args)\b/);
 
-   $dstat =~ 
s/^.\s*\#\s*define\s+$Ident(?:\([^\)]*\))?\s*//;
+   $dstat =~ s/^.\s*\#\s*define\s+$Ident(\([^\)]*\))?\s*//;
+   my $define_args = $1;
+   my $define_stmt = $dstat;
+   my @def_args = ();
+
+   if (defined $define_args && $define_args ne "") {
+   $define_args = substr($define_args, 1, 
length($define_args) - 2);
+   $define_args =~ s/\s*//g;
+   @def_args = split(",", $define_args);
+   }
+
$dstat =~ s/$;//g;
$dstat =~ s/\\\n.//g;
$dstat =~ s/^\s*//s;
@@ -4750,6 +4760,15 @@ sub process {
^\[
}x;
#print "REST<$rest> dstat<$dstat> ctx<$ctx>\n";
+
+   $ctx =~ s/\n*$//;
+   my $herectx = $here . "\n";
+   my $stmt_cnt = statement_rawlines($ctx);
+
+   for (my $n = 0; $n < $stmt_cnt; $n++) {
+   $herectx .= raw_line($linenr, $n) . "\n";
+   }
+
if ($dstat ne '' &&
$dstat !~ /^(?:$Ident|-?$Constant),$/ &&
# 10, // foo(),
$dstat !~ /^(?:$Ident|-?$Constant);$/ &&
# foo();
@@ -4765,13 +4784,6 @@ sub process {
$dstat !~ /^\(\{/ &&
# ({...
$ctx !~ 
/^.\s*#\s*define\s+TRACE_(?:SYSTEM|INCLUDE_FILE|INCLUDE_PATH)\b/)
{
-   $ctx =~ s/\n*$//;
-   my $herectx = $here . "\n";
-   my $cnt = statement_rawlines($ctx);
-
-   for (my $n = 0; $n < $cnt; $n++) {
-   $herectx .= raw_line($linenr, $n) . 
"\n";
-   }
 
if ($dstat =~ /;/) {

ERROR("MULTISTATEMENT_MACRO_USE_DO_WHILE",
@@ -4780,6 +4792,25 @@ sub process {
ERROR("COMPLEX_MACRO",
  "Macros with complex values 
should be enclosed in parentheses\n" . "$herectx");
}
+
+   }
+# check if any macro arguments are reused or may have other precedence issues
+   foreach my $arg (@def_args) {
+   next if ($arg =~ /\.\.\./);
+   my $tmp = $define_stmt;
+   $tmp =~ 
s/\b(typeof|__typeof__|__builtin\w+|typecheck\s*\(\s*$Type\s*,|\#+)\s*\(*\s*$arg\s*\)*\b//g;
+   $tmp =~ s/\#\#\s*$arg\b//g;
+   $tmp =~ s/\b$arg\s*\#\#//g;
+   my $use_cnt = $tmp =~ s/\b$arg\b//g;
+   if ($use_cnt > 1) {
+   CHK("MACRO_ARG_REUSE",
+   "Macro argument reuse '$arg' - 
possible side-effects?\n" . "$herectx");
+   }
+   if ($define_stmt =~ m/\b$arg\b\s*$Operators/m ||
+   $define_stmt =~ /$Operators\s*$arg\b/m) {
+   CHK("MACRO_ARG_PRECEDENCE",
+   "Macro argument '$arg' may be 
better as '($arg)' to avoid precedence issues\n" . "$herectx");
+   }

[PATCH] checkpatch: Add a --strict test for macro argument reuse and precedence

[Joe Perches]

Add a test for reuse of macro arguments to highlight any possible
side-effects from this reuse.

Avoid this check on token name pasting and when the
argument is used in a typeof or a __builtin.

Add a test for macro arguents that have leading or trailing operators
where the argument isn't parenthesized to avoid possible precedence
issues.

These tests are noisy so make them --strict.

Signed-off-by: Joe Perches 
---

This is a slight expansion of a patch I sent a few years back.

https://lkml.org/lkml/2012/11/6/151

This one at least runs.

Maybe it's useful to find some of the possible macro misuses,
but it is _very_ noisy.

 scripts/checkpatch.pl | 47 +++
 1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 8946904..921155f 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4714,7 +4714,17 @@ sub process {
$has_flow_statement = 1 if ($ctx =~ 
/\b(goto|return)\b/);
$has_arg_concat = 1 if ($ctx =~ /\#\#/ && $ctx !~ 
/\#\#\s*(?:__VA_ARGS__|args)\b/);
 
-   $dstat =~ 
s/^.\s*\#\s*define\s+$Ident(?:\([^\)]*\))?\s*//;
+   $dstat =~ s/^.\s*\#\s*define\s+$Ident(\([^\)]*\))?\s*//;
+   my $define_args = $1;
+   my $define_stmt = $dstat;
+   my @def_args = ();
+
+   if (defined $define_args && $define_args ne "") {
+   $define_args = substr($define_args, 1, 
length($define_args) - 2);
+   $define_args =~ s/\s*//g;
+   @def_args = split(",", $define_args);
+   }
+
$dstat =~ s/$;//g;
$dstat =~ s/\\\n.//g;
$dstat =~ s/^\s*//s;
@@ -4750,6 +4760,15 @@ sub process {
^\[
}x;
#print "REST<$rest> dstat<$dstat> ctx<$ctx>\n";
+
+   $ctx =~ s/\n*$//;
+   my $herectx = $here . "\n";
+   my $stmt_cnt = statement_rawlines($ctx);
+
+   for (my $n = 0; $n < $stmt_cnt; $n++) {
+   $herectx .= raw_line($linenr, $n) . "\n";
+   }
+
if ($dstat ne '' &&
$dstat !~ /^(?:$Ident|-?$Constant),$/ &&
# 10, // foo(),
$dstat !~ /^(?:$Ident|-?$Constant);$/ &&
# foo();
@@ -4765,13 +4784,6 @@ sub process {
$dstat !~ /^\(\{/ &&
# ({...
$ctx !~ 
/^.\s*#\s*define\s+TRACE_(?:SYSTEM|INCLUDE_FILE|INCLUDE_PATH)\b/)
{
-   $ctx =~ s/\n*$//;
-   my $herectx = $here . "\n";
-   my $cnt = statement_rawlines($ctx);
-
-   for (my $n = 0; $n < $cnt; $n++) {
-   $herectx .= raw_line($linenr, $n) . 
"\n";
-   }
 
if ($dstat =~ /;/) {

ERROR("MULTISTATEMENT_MACRO_USE_DO_WHILE",
@@ -4780,6 +4792,25 @@ sub process {
ERROR("COMPLEX_MACRO",
  "Macros with complex values 
should be enclosed in parentheses\n" . "$herectx");
}
+
+   }
+# check if any macro arguments are reused or may have other precedence issues
+   foreach my $arg (@def_args) {
+   next if ($arg =~ /\.\.\./);
+   my $tmp = $define_stmt;
+   $tmp =~ 
s/\b(typeof|__typeof__|__builtin\w+|typecheck\s*\(\s*$Type\s*,|\#+)\s*\(*\s*$arg\s*\)*\b//g;
+   $tmp =~ s/\#\#\s*$arg\b//g;
+   $tmp =~ s/\b$arg\s*\#\#//g;
+   my $use_cnt = $tmp =~ s/\b$arg\b//g;
+   if ($use_cnt > 1) {
+   CHK("MACRO_ARG_REUSE",
+   "Macro argument reuse '$arg' - 
possible side-effects?\n" . "$herectx");
+   }
+   if ($define_stmt =~ m/\b$arg\b\s*$Operators/m ||
+   $define_stmt =~ /$Operators\s*$arg\b/m) {
+   CHK("MACRO_ARG_PRECEDENCE",
+   "Macro argument '$arg' may be 
better as '($arg)' to avoid precedence issues\n" . "$herectx");
+   }
}
 
 # check for