[RFC] MAINTAINERS tag for cleanup robot

[trix]

A difficult part of automating commits is composing the subsystem
preamble in the commit log.  For the ongoing effort of a fixer producing
one or two fixes a release the use of 'treewide:' does not seem appropriate.

It would be better if the normal prefix was used.  Unfortunately normal is
not consistent across the tree.

So I am looking for comments for adding a new tag to the MAINTAINERS file

	D: Commit subsystem prefix

ex/ for FPGA DFL DRIVERS

	D: fpga: dfl:

Continuing with cleaning up clang's -Wextra-semi-stmt

A significant number of warnings are caused by function like macros with
a trailing semicolon.  For example.

#define FOO(a) a++; <-- extra, unneeded semicolon
void bar() {
	int v = 0;
	FOO(a);
} 

Clang will warn at the FOO(a); expansion location. Instead of removing
the semicolon there,  the fixer removes semicolon from the macro
definition.  After the fixer, the code will be:

#define FOO(a) a++
void bar() {
	int v = 0;
	FOO(a);
} 

The fixer review is
https://reviews.llvm.org/D91789

A run over allyesconfig for x86_64 finds 62 issues, 5 are false positives.
The false positives are caused by macros passed to other macros and by
some macro expansions that did not have an extra semicolon.

This cleans up about 1,000 of the current 10,000 -Wextra-semi-stmt
warnings in linux-next.

An update to [RFC] clang tooling cleanup
This change adds the clang-tidy-fix as a top level target and
uses it to do the cleaning.  The next iteration will do a loop of
cleaners.  This will mean breaking clang-tidy-fix out into its own
processing function 'run_fixers'.

Makefile: Add toplevel target clang-tidy-fix to makefile

Calls clang-tidy with -fix option for a set of checkers that
programatically fixes the kernel source in place, treewide.

Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
---
 Makefile                               |  7 ++++---
 scripts/clang-tools/run-clang-tools.py | 20 +++++++++++++++++---
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index 47a8add4dd28..57756dbb767b 100644
--- a/Makefile
+++ b/Makefile
@@ -1567,20 +1567,21 @@ help:
 	 echo  ''
 	@echo  'Static analysers:'
 	@echo  '  checkstack      - Generate a list of stack hogs'
 	@echo  '  versioncheck    - Sanity check on version.h usage'
 	@echo  '  includecheck    - Check for duplicate included header files'
 	@echo  '  export_report   - List the usages of all exported symbols'
 	@echo  '  headerdep       - Detect inclusion cycles in headers'
 	@echo  '  coccicheck      - Check with Coccinelle'
 	@echo  '  clang-analyzer  - Check with clang static analyzer'
 	@echo  '  clang-tidy      - Check with clang-tidy'
+	@echo  '  clang-tidy-fix  - Check and fix with clang-tidy'
 	@echo  ''
 	@echo  'Tools:'
 	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'
 	@echo  ''
 	@echo  'Kernel selftest:'
 	@echo  '  kselftest         - Build and run kernel selftest'
 	@echo  '                      Build, install, and boot kernel before'
 	@echo  '                      running kselftest on it'
 	@echo  '                      Run as root for full coverage'
 	@echo  '  kselftest-all     - Build kernel selftest'
@@ -1842,30 +1843,30 @@ nsdeps: modules
 quiet_cmd_gen_compile_commands = GEN     $@
       cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))
 
 $(extmod-prefix)compile_commands.json: scripts/clang-tools/gen_compile_commands.py \
 	$(if $(KBUILD_EXTMOD),,$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)) \
 	$(if $(CONFIG_MODULES), $(MODORDER)) FORCE
 	$(call if_changed,gen_compile_commands)
 
 targets += $(extmod-prefix)compile_commands.json
 
-PHONY += clang-tidy clang-analyzer
+PHONY += clang-tidy-fix clang-tidy clang-analyzer
 
 ifdef CONFIG_CC_IS_CLANG
 quiet_cmd_clang_tools = CHECK   $<
       cmd_clang_tools = $(PYTHON3) $(srctree)/scripts/clang-tools/run-clang-tools.py $@ $<
 
-clang-tidy clang-analyzer: $(extmod-prefix)compile_commands.json
+clang-tidy-fix clang-tidy clang-analyzer: $(extmod-prefix)compile_commands.json
 	$(call cmd,clang_tools)
 else
-clang-tidy clang-analyzer:
+clang-tidy-fix clang-tidy clang-analyzer:
 	@echo "$@ requires CC=clang" >&2
 	@false
 endif
 
 # Scripts to check various things for consistency
 # ---------------------------------------------------------------------------
 
 PHONY += includecheck versioncheck coccicheck export_report
 
 includecheck:
diff --git a/scripts/clang-tools/run-clang-tools.py b/scripts/clang-tools/run-clang-tools.py
index fa7655c7cec0..c177ca822c56 100755
--- a/scripts/clang-tools/run-clang-tools.py
+++ b/scripts/clang-tools/run-clang-tools.py
@@ -22,43 +22,57 @@ def parse_arguments():
     Returns:
         args: Dict of parsed args
         Has keys: [path, type]
     """
     usage = """Run clang-tidy or the clang static-analyzer on a
         compilation database."""
     parser = argparse.ArgumentParser(description=usage)
 
     type_help = "Type of analysis to be performed"
     parser.add_argument("type",
-                        choices=["clang-tidy", "clang-analyzer"],
+                        choices=["clang-tidy-fix", "clang-tidy", "clang-analyzer"],
                         help=type_help)
     path_help = "Path to the compilation database to parse"
     parser.add_argument("path", type=str, help=path_help)
 
     return parser.parse_args()
 
 
 def init(l, a):
     global lock
     global args
     lock = l
     args = a
 
 
 def run_analysis(entry):
     # Disable all checks, then re-enable the ones we want
     checks = "-checks=-*,"
-    if args.type == "clang-tidy":
+    fix = ""
+    header_filter = ""
+    if args.type == "clang-tidy-fix":
+        checks += "linuxkernel-macro-trailing-semi"
+        #
+        # Fix this
+        # #define M(a) a++; <-- clang-tidy fixes the problem here
+        # int f() {
+        #   int v = 0;
+        #   M(v);  <-- clang reports problem here
+        #   return v;
+        # }
+        fix += "-fix"
+        header_filter += "-header-filter=.*"
+    elif args.type == "clang-tidy":
         checks += "linuxkernel-*"
     else:
         checks += "clang-analyzer-*"
-    p = subprocess.run(["clang-tidy", "-p", args.path, checks, entry["file"]],
+    p = subprocess.run(["clang-tidy", "-p", args.path, checks, header_filter, fix, entry["file"]],
                        stdout=subprocess.PIPE,
                        stderr=subprocess.STDOUT,
                        cwd=entry["directory"])
     with lock:
         sys.stderr.buffer.write(p.stdout)
 
 
 def main():
     args = parse_arguments()
 
-- 
2.18.4