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[thirdparty/gcc.git] / gcc / jit / docs / cp / topics / locations.rst

.. Copyright (C) 2014-2019 Free Software Foundation, Inc.
   Originally contributed by David Malcolm <dmalcolm@redhat.com>

   This is free software: you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see
   <http://www.gnu.org/licenses/>.

.. default-domain:: cpp

Source Locations
================

.. class:: gccjit::location

   A `gccjit::location` encapsulates a source code location, so that
   you can (optionally) associate locations in your language with
   statements in the JIT-compiled code, allowing the debugger to
   single-step through your language.

   `gccjit::location` instances are optional: you can always omit them
   from any C++ API entrypoint accepting one.

   You can construct them using :func:`gccjit::context::new_location`.

   You need to enable :c:macro:`GCC_JIT_BOOL_OPTION_DEBUGINFO` on the
   :class:`gccjit::context` for these locations to actually be usable by
   the debugger:

   .. code-block:: cpp

     ctxt.set_bool_option (GCC_JIT_BOOL_OPTION_DEBUGINFO, 1);

.. function:: gccjit::location \
              gccjit::context::new_location (const char *filename, \
                                             int line, \
                                             int column)

   Create a `gccjit::location` instance representing the given source
   location.

Faking it
---------
If you don't have source code for your internal representation, but need
to debug, you can generate a C-like representation of the functions in
your context using :func:`gccjit::context::dump_to_file()`:

.. code-block:: cpp

  ctxt.dump_to_file ("/tmp/something.c",
                     1 /* update_locations */);

This will dump C-like code to the given path.  If the `update_locations`
argument is true, this will also set up `gccjit::location` information
throughout the context, pointing at the dump file as if it were a source
file, giving you *something* you can step through in the debugger.