llvm-project/clang-tools-extra/docs/MigratorUsage.rst

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===================
cpp11-migrate Usage
===================
``cpp11-migrate [options] <source0> [... <sourceN>] [-- [args]]``
``<source#>`` specifies the path to the source to migrate. This path may be
relative to the current directory.
At least one transform must be enabled.
General Command Line Options
============================
.. option:: -help
Displays tool usage instructions and command line options.
.. option:: -version
Displays the version information of this tool.
.. option:: -p[=<build-path>]
``<build-path>`` is the directory containing a file named
``compile_commands.json`` which provides compiler arguments for building each
source file. CMake can generate this file by specifying
``-DCMAKE_EXPORT_COMPILE_COMMANDS`` when running CMake. Ninja_, since v1.2
can also generate this file with ``ninja -t compdb``. If ``<build-path>`` is
not provided the ``compile_commands.json`` file is searched for through all
parent directories.
.. option:: -- [args]
Another way to provide compiler arguments is to specify all arguments on the
command line following ``--``. Arguments provided this way are used for
*every* source file.
If ``-p`` is not specified, ``--`` is necessary, even if no compiler
arguments are required.
.. _Ninja: http://martine.github.io/ninja/
.. option:: -risk=<risk-level>
Some transformations may cause a change in semantics. In such cases the
maximum acceptable risk level specified through the ``-risk`` command
line option decides whether or not a transformation is applied.
Three different risk level options are available:
``-risk=safe``
Perform only safe transformations.
``-risk=reasonable`` (default)
Enable transformations that may change semantics.
``-risk=risky``
Enable transformations that are likely to change semantics.
The meaning of risk is handled differently for each transform. See
:ref:`transform documentation <transforms>` for details.
.. option:: -final-syntax-check
After applying the final transform to a file, parse the file to ensure the
last transform did not introduce syntax errors. Syntax errors introduced by
earlier transforms are already caught when subsequent transforms parse the
file.
.. option:: -summary
Displays a summary of the number of changes each transform made or could have
made to each source file immediately after each transform is applied.
**Accepted** changes are those actually made. **Rejected** changes are those
that could have been made if the acceptable risk level were higher.
**Deferred** changes are those that might be possible but they might conflict
with other accepted changes. Re-applying the transform will resolve deferred
changes.
.. option:: -perf[=<directory>]
Turns on performance measurement and output functionality. The time it takes to
apply each transform is recorded by the migrator and written in JSON format
to a uniquely named file in the given ``<directory>``. All sources processed
by a single Migrator process are written to the same output file. If ``<directory>`` is
not provided the default is ``./migrate_perf/``.
The time recorded for a transform includes parsing and creating source code
replacements.
Transform-Specific Command Line Options
=======================================
.. option:: -loop-convert
Makes use of C++11 range-based for loops where possible. See
:doc:`LoopConvertTransform`.
.. option:: -use-nullptr
Makes use of the new C++11 keyword ``nullptr`` where possible.
See :doc:`UseNullptrTransform`.
.. option:: -user-null-macros=<string>
``<string>`` is a comma-separated list of user-defined macros that behave like
the ``NULL`` macro. The :option:`-use-nullptr` transform will replace these
macros along with ``NULL``. See :doc:`UseNullptrTransform`.
.. option:: -use-auto
Replace the type specifier of variable declarations with the ``auto`` type
specifier. See :doc:`UseAutoTransform`.
.. option:: -add-override
Adds the override specifier to member functions where it is appropriate. That
is, the override specifier is added to member functions that override a
virtual function in a base class and that don't already have the specifier.
See :doc:`AddOverrideTransform`.
.. option:: -override-macros
Tells the Add Override Transform to locate a macro that expands to
``override`` and use that macro instead of the ``override`` keyword directly.
If no such macro is found, ``override`` is still used. This option enables
projects that use such macros to maintain build compatibility with non-C++11
code.