clang-tidy: Add a basic python script to generate checks.

There are still a vast range of improvements that can be done to this,
but it seems like an ok initial version. Suggestions or patches are
highly welcome.

llvm-svn: 223766

diff --git a/clang-tools-extra/clang-tidy/add_new_check.py b/clang-tools-extra/clang-tidy/add_new_check.py
new file mode 100755 (executable)
index 0000000..873a2bd
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/add_new_check.py
@@ -0,0 +1,214 @@
+#!/usr/bin/env python
+#
+#===- add_new_check.py - clang-tidy check generator ----------*- python -*--===#
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===------------------------------------------------------------------------===#
+
+import os
+import re
+import sys
+
+
+# Adapts the module's CMakelist file. Returns 'True' if it could add a new entry
+# and 'False' if the entry already existed.
+def adapt_cmake(module_path, check_name_camel):
+  filename = os.path.join(module_path, 'CMakeLists.txt')
+  with open(filename, 'r') as f:
+    lines = f.read().split('\n')
+  # .split with separator returns one more element. Ignore it.
+  lines = lines[:-1]
+
+  cpp_file = check_name_camel + '.cpp'
+
+  # Figure out whether this check already exists.
+  for line in lines:
+    if line.strip() == cpp_file:
+      return False
+
+  with open(filename, 'w') as f:
+    cpp_found = False
+    file_added = False
+    for line in lines:
+      if not file_added and (line.endswith('.cpp') or cpp_found):
+        cpp_found = True
+        if line.strip() > cpp_file:
+          f.write('  ' + cpp_file + '\n')
+          file_added = True
+      f.write(line + '\n')
+
+  return True
+
+
+# Adds a header for the new check.
+def write_header(module_path, module, check_name, check_name_camel):
+  filename = os.path.join(module_path, check_name_camel) + '.h'
+  with open(filename, 'w') as f:
+    header_guard = ('LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_' + module.upper() +
+                    '_' + check_name.upper().replace('-', '_') + '_H')
+    f.write('//===--- ')
+    f.write(os.path.basename(filename))
+    f.write(' - clang-tidy')
+    f.write('-' * max(0, 43 - len(os.path.basename(filename))))
+    f.write('*- C++ -*-===//')
+    f.write("""
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef %(header_guard)s
+#define %(header_guard)s
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+
+class %(check_name)s : public ClangTidyCheck {
+public:
+  %(check_name)s(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace tidy
+} // namespace clang
+
+#endif // %(header_guard)s
+
+""" % {'header_guard': header_guard,
+       'check_name': check_name_camel})
+
+
+# Adds the implementation of the new check.
+def write_implementation(module_path, check_name_camel):
+  filename = os.path.join(module_path, check_name_camel) + '.cpp'
+  with open(filename, 'w') as f:
+    f.write('//===--- ')
+    f.write(os.path.basename(filename))
+    f.write(' - clang-tidy')
+    f.write('-' * max(0, 52 - len(os.path.basename(filename))))
+    f.write('-===//')
+    f.write("""
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "%(check_name)s.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+
+void %(check_name)s::registerMatchers(MatchFinder *Finder) {
+  // FIXME: Add matchers.
+  Finder->addMatcher(functionDecl().bind("x"), this);
+}
+
+void %(check_name)s::check(const MatchFinder::MatchResult &Result) {
+  // FIXME: Add callback implementation.
+  const FunctionDecl *MatchedDecl = Result.Nodes.getNodeAs<FunctionDecl>("x");
+  diag(MatchedDecl->getLocation(), "Dummy warning");
+}
+
+} // namespace tidy
+} // namespace clang
+
+""" % {'check_name': check_name_camel})
+
+
+# Modifies the module to include the new check.
+def adapt_module(module_path, module, check_name, check_name_camel):
+  filename = os.path.join(module_path, module.capitalize() + 'TidyModule.cpp')
+  with open(filename, 'r') as f:
+    lines = f.read().split('\n')
+  # .split with separator returns one more element. Ignore it.
+  lines = lines[:-1]
+
+  with open(filename, 'w') as f:
+    header_added = False
+    header_found = False
+    check_added = False
+    check_decl = ('    CheckFactories.registerCheck<' + check_name_camel +
+                  '>(\n        "' + module + '-' + check_name + '");\n')
+
+    for line in lines:
+      if not header_added:
+        match = re.search('#include "(.*)"', line)
+        if match:
+          header_found = True
+          if match.group(1) > check_name_camel:
+            header_added = True
+            f.write('#include "' + check_name_camel + '.h"\n')
+        elif header_found:
+          header_added = True
+          f.write('#include "' + check_name_camel + '.h"\n')
+
+      if not check_added:
+        if line.strip() == '}':
+          check_added = True
+          f.write(check_decl)
+        else:
+          match = re.search('registerCheck<(.*)>', line)
+          if match and match.group(1) > check_name_camel:
+            check_added = True
+            f.write(check_decl)
+      f.write(line + '\n')
+
+
+# Adds a test for the check.
+def write_test(module_path, module, check_name):
+  filename = os.path.join(module_path, '../../test/clang-tidy',
+                          module + '-' + check_name + '.cpp')
+  with open(filename, 'w') as f:
+    f.write('// RUN: $(dirname %s)/check_clang_tidy.sh %s ' + module + '-' + 
+            check_name + ' %t\n')
+    f.write("""// REQUIRES: shell
+
+// FIXME: Add something that trigger the check here
+void f();
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: Dummy warning
+
+// FIXME: Add something that doesn't trigger the check here
+int i;
+// CHECK-MESSAGES-NOT: warning:""")
+
+def main():
+  if len(sys.argv) != 3:
+    print 'Usage: add_new_check.py <module> <check>, e.g.\n'
+    print 'add_new_check.py misc else-after-return\n'
+    return
+
+  module = sys.argv[1]
+  check_name = sys.argv[2]
+  check_name_camel = ''.join(map(lambda elem: elem.capitalize(),
+                                 check_name.split('-'))) + 'Check'
+  clang_tidy_path = os.path.dirname(sys.argv[0])
+  module_path = os.path.join(clang_tidy_path, module)
+
+  if not adapt_cmake(module_path, check_name_camel):
+    return
+  write_header(module_path, module, check_name, check_name_camel)
+  write_implementation(module_path, check_name_camel)
+  adapt_module(module_path, module, check_name, check_name_camel)
+  write_test(module_path, module, check_name)
+
+
+if __name__ == '__main__':
+  main()