[diagtool] Install diagtool

[JDevlieghere]

Summary

Although not very well known, diagtool is an incredibly convenient utility for dealing with diagnostics. I believe it's worth adding this to the install target.

[dexonsmith]

This SGTM, but I wouldn't mind hearing from others. I wonder if this is worth a quick RFC on cfe-dev?

[JDevlieghere]

In D46694#1094617, @dexonsmith wrote:

This SGTM, but I wouldn't mind hearing from others. I wonder if this is worth a quick RFC on cfe-dev?

Sounds good, I've created a thread here: http://lists.llvm.org/pipermail/cfe-dev/2018-May/057946.html

[vsk]

Sgtm. I think it would be worthwhile to release-note this.

cfe/trunk/docs/CommandGuide/diagtool.rst

+diagtool - clang diagnostics tool
+=================================
+
+SYNOPSIS
+--------
+
+:program:`diagtool` *command* [*args*]
+
+DESCRIPTION
+-----------
+
+:program:`diagtool` is a combination of four tool for dealing with diagnostics in :program:`clang`.
+
+SUBCOMMANDS
+-----------
+
+:program:`diagtool` is separated into several subcommands each tailored to a
+different purpose. A brief summary of each command follows, with more detail in
+the sections that follow.
+
+  * :ref:`find_diagnostic_id` - Print the id of the given diagnostic.
+  * :ref:`list_warnings` - List warnings and their corresponding flags.
+  * :ref:`show_enabled` - Show which warnings are enabled for a given command line.
+  * :ref:`tree` - Show warning flags in a tree view.
+
+.. _find_diagnostic_id:
+
+find-diagnostic-id
+~~~~~~~~~~~~~~~~~~
+
+:program:`diagtool` find-diagnostic-id *diagnostic-name*
+
+.. _list_warnings:
+
+list-warnings
+~~~~~~~~~~~~~
+
+:program:`diagtool` list-warnings
+
+.. _show_enabled:
+
+show-enabled
+~~~~~~~~~~~~
+
+:program:`diagtool` show-enabled [*options*] *filename ...*
+
+.. _tree:
+
+tree
+~~~~
+
+:program:`diagtool` tree [*diagnostic-group*]

cfe/trunk/docs/CommandGuide/index.rst

 
 Basic Commands
 ~~~~~~~~~~~~~~
 
 .. toctree::
    :maxdepth: 1
 
    clang
+   diagtool

cfe/trunk/docs/ReleaseNotes.rst

- Clang implements the proposed resolution of LWG issue 2358, along with the
   `corresponding change to the Itanium C++ ABI
   <https://github.com/itanium-cxx-abi/cxx-abi/pull/51>`_, which make classes
   containing only unnamed non-zero-length bit-fields be considered non-empty.
   This is an ABI break compared to prior Clang releases, but makes Clang
   generate code that is ABI-compatible with other compilers. The old
   behavior can be restored by setting ``-fclang-abi-compat`` to ``6`` or
   lower.
 
+- An existing tool named ``diagtool`` has been added to the release. As the
+  name suggests, it helps with dealing with diagnostics in ``clang``, such as
+  finding out the warning hierarchy, and which of them are enabled by default
+  or for a particular compiler invocation.
+
 - ...
 
 New Compiler Flags
 ------------------
 
 - :option:`-fstrict-float-cast-overflow` and
   :option:`-fno-strict-float-cast-overflow`.
 

cfe/trunk/tools/diagtool/CMakeLists.txt

add_clang_executable(diagtool
   TreeView.cpp
 )
 
 target_link_libraries(diagtool
   PRIVATE
   clangBasic
   clangFrontend
   )
+
+if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
+  install(TARGETS diagtool
+    COMPONENT diagtool
+    RUNTIME DESTINATION bin)
+
+  if (NOT CMAKE_CONFIGURATION_TYPES)
+    add_llvm_install_targets(install-diagtool
+      DEPENDS diagtool
+      COMPONENT diagtool)
+  endif()
+endif()