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authorNathan Huckleberry <nhuck@google.com>2020-08-22 23:56:18 +0900
committerMasahiro Yamada <masahiroy@kernel.org>2020-08-27 00:44:33 +0900
commit6ad7cbc01527223f3f92baac9b122f15651cf76b (patch)
tree1d3e544ead030842f86589df1222fc9738814992
parent8b61f748e2a022f9028c612e44b68ad61caec474 (diff)
Makefile: Add clang-tidy and static analyzer support to makefile
This patch adds clang-tidy and the clang static-analyzer as make targets. The goal of this patch is to make static analysis tools usable and extendable by any developer or researcher who is familiar with basic c++. The current static analysis tools require intimate knowledge of the internal workings of the static analysis. Clang-tidy and the clang static analyzers expose an easy to use api and allow users unfamiliar with clang to write new checks with relative ease. ===Clang-tidy=== Clang-tidy is an easily extendable 'linter' that runs on the AST. Clang-tidy checks are easy to write and understand. A check consists of two parts, a matcher and a checker. The matcher is created using a domain specific language that acts on the AST (https://clang.llvm.org/docs/LibASTMatchersReference.html). When AST nodes are found by the matcher a callback is made to the checker. The checker can then execute additional checks and issue warnings. Here is an example clang-tidy check to report functions that have calls to local_irq_disable without calls to local_irq_enable and vice-versa. Functions flagged with __attribute((annotation("ignore_irq_balancing"))) are ignored for analysis. (https://reviews.llvm.org/D65828) ===Clang static analyzer=== The clang static analyzer is a more powerful static analysis tool that uses symbolic execution to find bugs. Currently there is a check that looks for potential security bugs from invalid uses of kmalloc and kfree. There are several more general purpose checks that are useful for the kernel. The clang static analyzer is well documented and designed to be extensible. (https://clang-analyzer.llvm.org/checker_dev_manual.html) (https://github.com/haoNoQ/clang-analyzer-guide/releases/download/v0.1/clang-analyzer-guide-v0.1.pdf) The main draw of the clang tools is how accessible they are. The clang documentation is very nice and these tools are built specifically to be easily extendable by any developer. They provide an accessible method of bug-finding and research to people who are not overly familiar with the kernel codebase. Signed-off-by: Nathan Huckleberry <nhuck@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
-rw-r--r--MAINTAINERS1
-rw-r--r--Makefile20
-rwxr-xr-xscripts/clang-tools/gen_compile_commands.py (renamed from scripts/gen_compile_commands.py)0
-rwxr-xr-xscripts/clang-tools/run-clang-tools.py74
4 files changed, 93 insertions, 2 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index f0068bceeb61..05bebba204cf 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4247,6 +4247,7 @@ W: https://clangbuiltlinux.github.io/
B: https://github.com/ClangBuiltLinux/linux/issues
C: irc://chat.freenode.net/clangbuiltlinux
F: Documentation/kbuild/llvm.rst
+F: scripts/clang-tools/
K: \b(?i:clang|llvm)\b
CLEANCACHE API
diff --git a/Makefile b/Makefile
index 07fd96a25a20..37739ee53f27 100644
--- a/Makefile
+++ b/Makefile
@@ -634,7 +634,7 @@ endif
# in addition to whatever we do anyway.
# Just "make" or "make all" shall build modules as well
-ifneq ($(filter all modules nsdeps %compile_commands.json,$(MAKECMDGOALS)),)
+ifneq ($(filter all modules nsdeps %compile_commands.json clang-%,$(MAKECMDGOALS)),)
KBUILD_MODULES := 1
endif
@@ -1583,6 +1583,8 @@ help:
@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 ''
@echo 'Tools:'
@echo ' nsdeps - Generate missing symbol namespace dependencies'
@@ -1848,13 +1850,27 @@ 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/gen_compile_commands.py \
+$(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
+
+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
+ $(call cmd,clang_tools)
+else
+clang-tidy clang-analyzer:
+ @echo "$@ requires CC=clang" >&2
+ @false
+endif
+
# Scripts to check various things for consistency
# ---------------------------------------------------------------------------
diff --git a/scripts/gen_compile_commands.py b/scripts/clang-tools/gen_compile_commands.py
index 19963708bcf8..19963708bcf8 100755
--- a/scripts/gen_compile_commands.py
+++ b/scripts/clang-tools/gen_compile_commands.py
diff --git a/scripts/clang-tools/run-clang-tools.py b/scripts/clang-tools/run-clang-tools.py
new file mode 100755
index 000000000000..fa7655c7cec0
--- /dev/null
+++ b/scripts/clang-tools/run-clang-tools.py
@@ -0,0 +1,74 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (C) Google LLC, 2020
+#
+# Author: Nathan Huckleberry <nhuck@google.com>
+#
+"""A helper routine run clang-tidy and the clang static-analyzer on
+compile_commands.json.
+"""
+
+import argparse
+import json
+import multiprocessing
+import os
+import subprocess
+import sys
+
+
+def parse_arguments():
+ """Set up and parses command-line 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"],
+ 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":
+ checks += "linuxkernel-*"
+ else:
+ checks += "clang-analyzer-*"
+ p = subprocess.run(["clang-tidy", "-p", args.path, checks, entry["file"]],
+ stdout=subprocess.PIPE,
+ stderr=subprocess.STDOUT,
+ cwd=entry["directory"])
+ with lock:
+ sys.stderr.buffer.write(p.stdout)
+
+
+def main():
+ args = parse_arguments()
+
+ lock = multiprocessing.Lock()
+ pool = multiprocessing.Pool(initializer=init, initargs=(lock, args))
+ # Read JSON data into the datastore variable
+ with open(args.path, "r") as f:
+ datastore = json.load(f)
+ pool.map(run_analysis, datastore)
+
+
+if __name__ == "__main__":
+ main()