Update clang-tidy documentation.

[alexfh]

Summary

Updated the help message, updated description of -checks=, removed
mentions of -disable-checks.

[alexfh]

Added information about -checks='*' to -list-checks help message. Reformatted
option descriptions, so that they fit into 80 columns on the terminal.

[klimek]

lg

clang-tidy/tool/ClangTidyMain.cpp

38

I think this needs some more explanation of how you decide whether something is positive or negative, whether order is important, how it relates to the default checks, etc.

[alexfh]

Please take a look if the new description is more clear.

[klimek]

lg

clang-tidy/tool/ClangTidyMain.cpp

 
 const char DefaultChecks[] =
     "*,"                       // Enable all checks, except these:
     "-clang-analyzer-alpha*,"  // Too many false positives.
     "-llvm-include-order,"     // Not implemented yet.
     "-llvm-namespace-comment," // Not complete.
     "-google-*,";              // Doesn't apply to LLVM.
 static cl::opt<std::string>
-Checks("checks",
-       cl::desc("Comma-separated list of positive and negative globs matching\n"
-                "the names of the checks to be run."),
+Checks("checks", cl::desc("Comma-separated list of globs with optional '-'\n"
+                          "prefix. Globs are processed in order of appearance\n"
+                          "in the list. Globs without '-' prefix add checks\n"
+                          "with matching names to the set, globs with the '-'\n"
+                          "prefix remove checks with matching names from the\n"
+                          "set of enabled checks."),
        cl::init(""), cl::cat(ClangTidyCategory));
-static cl::opt<std::string> HeaderFilter(
-    "header-filter",
-    cl::desc("Regular expression matching the names of the headers to output\n"
-             "diagnostics from. Diagnostics from the main file of each\n"
+static cl::opt<std::string>
+HeaderFilter("header-filter",
+             cl::desc("Regular expression matching the names of the\n"
+                      "headers to output diagnostics from.\n"
+                      "Diagnostics from the main file of each\n"
                       "translation unit are always displayed."),
              cl::init(""), cl::cat(ClangTidyCategory));
 static cl::opt<bool> Fix("fix", cl::desc("Fix detected errors if possible."),
                          cl::init(false), cl::cat(ClangTidyCategory));
 
-static cl::opt<bool> ListChecks("list-checks",
-                                cl::desc("List all enabled checks and exit."),
-                                cl::init(false), cl::cat(ClangTidyCategory));
+static cl::opt<bool>
+ListChecks("list-checks",
+           cl::desc("List all enabled checks and exit. Use with\n"
+                    "-checks='*' to list all available checks."),
 
-static cl::opt<bool> AnalyzeTemporaryDtors(
-    "analyze-temporary-dtors",
-    cl::desc("Enable temporary destructor-aware analysis in clang-analyzer- "
-             "checks."),
-    cl::init(false),
-    cl::cat(ClangTidyCategory));
+static cl::opt<bool>
+AnalyzeTemporaryDtors("analyze-temporary-dtors",
+                      cl::desc("Enable temporary destructor-aware analysis in\n"
+                               "clang-analyzer- checks."),
+                      cl::init(false), cl::cat(ClangTidyCategory));
 
 static void printStats(const clang::tidy::ClangTidyStats &Stats) {
   unsigned ErrorsIgnored = Stats.ErrorsIgnoredNOLINT +
                            Stats.ErrorsIgnoredCheckFilter +
                            Stats.ErrorsIgnoredNonUserCode;
   if (ErrorsIgnored) {
     llvm::errs() << "Suppressed " << ErrorsIgnored << " warnings (";
     StringRef Separator = "";

docs/clang-tidy.rst

 compilation options on the command line after ``--``:
 
 .. code-block:: bash
 
   $ clang-tidy test.cpp -- -Imy_project/include -DMY_DEFINES ...
 
 :program:`clang-tidy` has its own checks and can also run Clang static analyzer
 checks. Each check has a name and the checks to run can be chosen using the
-``-checks=`` and ``-disable-checks=`` options. :program:`clang-tidy` selects the
-checks with names matching the regular expression specified by the ``-checks=``
-option and not matching the one specified by the ``-disable-checks=`` option.
+``-checks=`` option, which specifies a comma-separated list of positive and
+negative (prefixed with ``-``) globs. Positive globs add subsets of checks,
+negative globs remove them. For example,
 
-The ``-list-checks`` option lists all the enabled checks. It can be used with or
-without ``-checks=`` and/or ``-disable-checks=``.
+.. code-block:: bash
+
+  $ clang-tidy test.cpp -checks='-*,clang-analyzer-*,-clang-analyzer-alpha*'
+
+will disable all default checks (``-*``) and enable all ``clang-analyzer-*``
+checks except for ``clang-analyzer-alpha*`` ones.
+
+The ``-list-checks`` option lists all the enabled checks. When used without
+``-checks=``, it shows checks enabled by default. Use ``-checks='*'`` to see all
+available checks or with any other value of ``-checks=`` to see which checks are
+enabled by this value.
 
 There are currently three groups of checks:
 
 * Checks related to the LLVM coding conventions have names starting with
   ``llvm-``.
 
 * Checks related to the Google coding conventions have names starting with
   ``google-``.
 
+* Checks with names starting with ``misc-`` don't relate to any particular
+  coding style.
+
 * Clang static analyzer checks are named starting with ``clang-analyzer-``.
 
 
 The ``-fix`` flag instructs :program:`clang-format` to fix found errors if
 supported by corresponding checks.
 
 An overview of all the command-line options:
 
General options:
     -help                    - Display available options (-help-hidden
                                for more)
     -help-list               - Display list of available options
                                (-help-list-hidden for more)
     -version                 - Display the version of this program
 
   clang-tidy options:
 
-    -checks=<string>         - Regular expression matching the names of
-                               the checks to be run.
-    -disable-checks=<string> - Regular expression matching the names of
-                               the checks to disable.
+    -analyze-temporary-dtors - Enable temporary destructor-aware analysis in
+                               clang-analyzer- checks.
+    -checks=<string>         - Comma-separated list of globs with optional '-'
+                               prefix. Globs are processed in order of appearance
+                               in the list. Globs without '-' prefix add checks
+                               with matching names to the set, globs with the '-'
+                               prefix remove checks with matching names from the
+                               set of enabled checks.
     -fix                     - Fix detected errors if possible.
-    -list-checks             - List all enabled checks and exit.
+    -header-filter=<string>  - Regular expression matching the names of the
+                               headers to output diagnostics from.
+                               Diagnostics from the main file of each
+                               translation unit are always displayed.
+    -list-checks             - List all enabled checks and exit. Use with
+                               -checks='*' to list all available checks.
     -p=<string>              - Build path
 
   -p <build-path> is used to read a compile command database.
 
     For example, it can be a CMake build directory in which a file named
     compile_commands.json exists (use -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
     CMake option to get this output). When no build path is specified,
     a search for compile_commands.json will be attempted through all