[PATCH RFC] checkpatch: extend attributes check to handle more patterns

[Dwaipayan Ray <dwaipayanray1@gmail.com>]

It is generally preferred that the macros from
include/linux/compiler_attributes.h are used, unless there
is a reason not to.

Checkpatch currently checks __attribute__ for each of
packed, aligned, printf, scanf, and weak. Other declarations
in compiler_attributes.h are not handled.

Add more definitions to the attribute check.
The following patterns are added:

__alias__(#symbol)
__always_inline__
__assume_aligned__(a, ## __VA_ARGS__)
__cold__
__const__
__copy__(symbol)
__designated_init__
__externally_visible__
__gnu_inline__
__malloc__
__mode__(x)
__no_caller_saved_registers__
__noclone__
__fallthrough__
__noinline__
__nonstring__
__noreturn__
__pure__
__unused__
__used__

Link: https://lore.kernel.org/linux-kernel-mentees/3ec15b41754b01666d94b76ce51b9832c2dd577a.camel@perches.com/
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
---
 scripts/checkpatch.pl | 199 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 163 insertions(+), 36 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 7e505688257a..968adcb15793 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6155,50 +6155,177 @@ sub process {
 			}
 		}
 
-# Check for __attribute__ packed, prefer __packed
+# Check for compiler attributes
 		if ($realfile !~ m@\binclude/uapi/@ &&
-		    $line =~ /\b__attribute__\s*\(\s*\(.*\bpacked\b/) {
-			WARN("PREFER_PACKED",
-			     "__packed is preferred over __attribute__((packed))\n" . $herecurr);
-		}
+		    $line =~ /\b__attribute__\s*\(\s*\((.*)\)\s*\)/) {
+			my $attr = trim($1);
 
-# Check for __attribute__ aligned, prefer __aligned
-		if ($realfile !~ m@\binclude/uapi/@ &&
-		    $line =~ /\b__attribute__\s*\(\s*\(.*aligned/) {
-			WARN("PREFER_ALIGNED",
-			     "__aligned(size) is preferred over __attribute__((aligned(size)))\n" . $herecurr);
-		}
+			# Check for __attribute__ alias, prefer __alias
+			if ($attr =~/^_*alias_*/) {
+				WARN("PREFER_ALIAS",
+				     "__alias(symbol) is preferred over __attribute__((alias(#symbol)))\n" . $herecurr);
+			}
 
-# Check for __attribute__ section, prefer __section
-		if ($realfile !~ m@\binclude/uapi/@ &&
-		    $line =~ /\b__attribute__\s*\(\s*\(.*_*section_*\s*\(\s*("[^"]*")/) {
-			my $old = substr($rawline, $-[1], $+[1] - $-[1]);
-			my $new = substr($old, 1, -1);
-			if (WARN("PREFER_SECTION",
-				 "__section($new) is preferred over __attribute__((section($old)))\n" . $herecurr) &&
-			    $fix) {
-				$fixed[$fixlinenr] =~ s/\b__attribute__\s*\(\s*\(\s*_*section_*\s*\(\s*\Q$old\E\s*\)\s*\)\s*\)/__section($new)/;
+			# Check for __attribute__ aligned(size), prefer __aligned(size)
+			if ($attr =~/^_*aligned_*\(/) {
+				WARN("PREFER_ALIGNED",
+				     "__aligned(size) is preferred over __attribute__((__aligned__(size)))\n" . $herecurr);
 			}
-		}
 
-# Check for __attribute__ format(printf, prefer __printf
-		if ($realfile !~ m@\binclude/uapi/@ &&
-		    $line =~ /\b__attribute__\s*\(\s*\(\s*format\s*\(\s*printf/) {
-			if (WARN("PREFER_PRINTF",
-				 "__printf(string-index, first-to-check) is preferred over __attribute__((format(printf, string-index, first-to-check)))\n" . $herecurr) &&
-			    $fix) {
-				$fixed[$fixlinenr] =~ s/\b__attribute__\s*\(\s*\(\s*format\s*\(\s*printf\s*,\s*(.*)\)\s*\)\s*\)/"__printf(" . trim($1) . ")"/ex;
+			# Check for __attribute__ aligned, prefer __aligned_largest
+			if ($attr =~/^_*aligned_*$/) {
+				WARN("PREFER_ALIGNED_LARGEST",
+				     "__aligned_largest is preferred over __attribute__((__aligned__))\n" . $herecurr);
+			}
 
+			# Check for __attribute__ always_inline, prefer __always_inline
+			if ($attr =~/^_*always_inline_*/) {
+				WARN("PREFER_ALWAYS_INLINE",
+				     "__always_inline is preferred over __attribute__((__always_inline__))\n" . $herecurr);
 			}
-		}
 
-# Check for __attribute__ format(scanf, prefer __scanf
-		if ($realfile !~ m@\binclude/uapi/@ &&
-		    $line =~ /\b__attribute__\s*\(\s*\(\s*format\s*\(\s*scanf\b/) {
-			if (WARN("PREFER_SCANF",
-				 "__scanf(string-index, first-to-check) is preferred over __attribute__((format(scanf, string-index, first-to-check)))\n" . $herecurr) &&
-			    $fix) {
-				$fixed[$fixlinenr] =~ s/\b__attribute__\s*\(\s*\(\s*format\s*\(\s*scanf\s*,\s*(.*)\)\s*\)\s*\)/"__scanf(" . trim($1) . ")"/ex;
+			# Check for __attribute__ assume_aligned, prefer __assume_aligned
+			if ($attr =~/^_*assume_aligned_*/) {
+				WARN("PREFER_ASSUME_ALIGNED",
+				     "__asume_aligned(a, ...) is preferred over __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ cold, prefer __cold
+			if ($attr =~ /^_*cold_*/) {
+				WARN("PREFER_COLD",
+				     "__cold is preferred over __attribute__((__cold__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ const, prefer __attribute_const
+			if ($attr =~ /^_*const_*/) {
+				WARN("PREFER_CONST",
+				     "__attribute_const is preferred over __attribute__((__const__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ copy, prefer __copy
+			if ($attr =~ /^_*copy_*/) {
+				WARN("PREFER_COPY",
+				     "__copy(symbol) is preferred over __attribute__((__copy__(symbol)))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ desginated_init, prefer __designated_init
+			if ($attr =~ /^_*designated_init_*/) {
+				WARN("PREFER_DESIGNATED_INIT",
+				     "__designated_init is preferred over __attribute__((__designated_init__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ externally_visible, prefer __visible
+			if ($attr =~ /^_*externally_visible_*/) {
+				WARN("PREFER_VISIBLE",
+				     "__visible is preferred over __attribute__((__externally_visible__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ format(printf, prefer __printf
+			if ($attr =~ /^_*format_*\s*\(\s*printf/) {
+				if (WARN("PREFER_PRINTF",
+				         "__printf(string-index, first-to-check) is preferred over __attribute__((format(printf, string-index, first-to-check)))\n" . $herecurr) &&
+					$fix) {
+					$fixed[$fixlinenr] =~ s/\b__attribute__\s*\(\s*\(\s*format\s*\(\s*printf\s*,\s*(.*)\)\s*\)\s*\)/"__printf(" . trim($1) . ")"/ex;
+
+				}
+			}
+
+			# Check for __attribute__ format(scanf, prefer __scanf
+			if ($attr =~ /^_*format_*\s*\(\s*scanf\b/) {
+				if (WARN("PREFER_SCANF",
+				         "__scanf(string-index, first-to-check) is preferred over __attribute__((format(scanf, string-index, first-to-check)))\n" . $herecurr) &&
+					$fix) {
+					$fixed[$fixlinenr] =~ s/\b__attribute__\s*\(\s*\(\s*format\s*\(\s*scanf\s*,\s*(.*)\)\s*\)\s*\)/"__scanf(" . trim($1) . ")"/ex;
+				}
+			}
+
+			# Check for __attribute__ gnu_inline, prefer __gnu_inline
+			if ($attr =~ /^_*gnu_inline_*/) {
+				WARN("PREFER_GNU_INLINE",
+				     "__gnu_inline is preferred over __attribute__((__gnu_inline__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ malloc, prefer __malloc
+			if ($attr =~ /^_*malloc_*/) {
+				WARN("PREFER_MALLOC",
+				     "__malloc is preferred over __attribute__((__malloc__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ mode, prefer __mode
+			if ($attr =~ /^_*mode_*/) {
+				WARN("PREFER_MODE",
+				     "__mode(x) is preferred over __attribute__((__mode__(x)))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ no_caller_saved_registers, prefer __no_caller_saved_registers
+			if ($attr =~ /^_*no_caller_saved_registers_*/) {
+				WARN("PREFER_NO_CALLER_SAVED_REGISTERS",
+				     "__no_caller_saved_registers is preferred over __attribute__((__no_caller_saved_registers__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ noclone, prefer __noclone
+			if ($attr =~ /^_*noclone_*/) {
+				WARN("PREFER_NOCLONE",
+				     "__noclone is preferred over __attribute__((__noclone__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ fallthrough, prefer fallthrough
+			if ($attr =~ /^_*fallthrough_*/) {
+				WARN("PREFER_FALLTHROUGH",
+				     "fallthrough is preferred over __attribute__((__fallthrough__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ noinline, prefer noinline
+			if ($attr =~ /^_*noinline_*/) {
+				WARN("PREFER_NOINLINE",
+				     "noinline is preferred over __attribute__((__noinline__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ nonstring, prefer __nonstring
+			if ($attr =~ /^_*nonstring_*/) {
+				WARN("PREFER_NONSTRING",
+				     "__nonstring is preferred over __attribute__((__nonstring__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ noreturn, prefer __noreturn
+			if ($attr =~ /^_*noreturn_*/) {
+				WARN("PREFER_NORETURN",
+				     "__noreturn is preferred over __attribute__((__noreturn__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ packed, prefer __packed
+			if ($attr =~ /^_*packed_*/) {
+				WARN("PREFER_PACKED",
+				     "__packed is preferred over __attribute__((__packed__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ pure, prefer __pure
+			if ($attr =~ /^_*pure_*/) {
+				WARN("PREFER_PURE",
+				     "__pure is preferred over __attribute__((__pure__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ section, prefer __section
+			if ($attr =~ /^_*section_*\s*\(\s*("[^"]*")/) {
+				my $old = substr($rawline, $-[1], $+[1] - $-[1]);
+				my $new = substr($old, 1, -1);
+				if (WARN("PREFER_SECTION",
+				         "__section($new) is preferred over __attribute__((section($old)))\n" . $herecurr) &&
+					$fix) {
+					$fixed[$fixlinenr] =~ s/\b__attribute__\s*\(\s*\(\s*_*section_*\s*\(\s*\Q$old\E\s*\)\s*\)\s*\)/__section($new)/;
+				}
+			}
+
+			# Check for __attribute__ unused, prefer __always_unused or __maybe_unused
+			if ($attr =~ /^_*unused_*/) {
+				WARN("PREFER_UNUSED",
+				     "__always_unused or __maybe_unused is preferred over __attribute__((__unused__))\n" . $herecurr);
+			}
+
+			# Check for __attribute__ used, prefer __used
+			if ($attr =~ /^_*used_*/) {
+				WARN("PREFER_USED",
+				     "__used is preferred over __attribute__((__used__))\n" . $herecurr);
 			}
 		}
 
-- 
2.27.0