added option to disable invariant checks and added more build documentation

Jamfile

@@ -152,6 +152,9 @@ rule building ( properties * )
 feature bandwidth-limit-logging : off on : composite propagated link-incompatible ;
 feature.compose <bandwidth-limit-logging>on : <define>TORRENT_VERBOSE_BANDWIDTH_LIMIT ;
 
+feature invariant-checks : on off : composite propagated link-incompatible ;
+feature.compose <invariant-checks>off : <define>TORRENT_DISABLE_INVARIANT_CHECKS ;
+
 feature disk-stats : off on : composite propagated link-incompatible ;
 feature.compose <disk-stats>on : <define>TORRENT_DISK_STATS ;
 

docs/building.html

@@ -291,6 +291,26 @@ API is used.</li>
 </ul>
 </td>
 </tr>
+<tr><td><tt class="docutils literal"><span class="pre">invariant-checks</span></tt></td>
+<td><p class="first">This setting only affects debug builds (where
+<tt class="docutils literal"><span class="pre">NDEBUG</span></tt> is not defined). It defaults to <tt class="docutils literal"><span class="pre">on</span></tt>.</p>
+<ul class="last simple">
+<li><tt class="docutils literal"><span class="pre">on</span></tt> - internal invariant checks are enabled.</li>
+<li><tt class="docutils literal"><span class="pre">off</span></tt> - internal invariant checks are
+disabled. The resulting executable will run
+faster than a regular debug build.</li>
+</ul>
+</td>
+</tr>
+<tr><td><tt class="docutils literal"><span class="pre">debug-symbols</span></tt></td>
+<td><ul class="first last simple">
+<li><tt class="docutils literal"><span class="pre">on</span></tt> - default for debug builds. This setting
+is useful for building release builds with
+symbols.</li>
+<li><tt class="docutils literal"><span class="pre">off</span></tt> - default for release builds.</li>
+</ul>
+</td>
+</tr>
 </tbody>
 </table>
 <p>The <tt class="docutils literal"><span class="pre">variant</span></tt> feature is <em>implicit</em>, which means you don't need to specify
@@ -558,6 +578,14 @@ non-ansi characters.</td>
 <td>Defining this will disable the ability to
 resolve countries of origin for peer IPs.</td>
 </tr>
+<tr><td><tt class="docutils literal"><span class="pre">TORRENT_DISABLE_INVARIANT_CHECKS</span></tt></td>
+<td>This will disable internal invariant checks in
+libtorrent. The invariant checks can sometime
+be quite expensive, they typically don't scale
+very well. This option can be used to still
+build in debug mode, with asserts enabled, but
+make the resulting executable faster.</td>
+</tr>
 </tbody>
 </table>
 <p>If you experience that libtorrent uses unreasonable amounts of cpu, it will

docs/building.rst

@@ -262,6 +262,19 @@ Build features:
 |                        | * ``unicode`` - The unicode version of the win32   |
 |                        |   API is used.                                     |
 +------------------------+----------------------------------------------------+
+| ``invariant-checks``   | This setting only affects debug builds (where      |
+|                        | ``NDEBUG`` is not defined). It defaults to ``on``. |
+|                        |                                                    |
+|                        | * ``on`` - internal invariant checks are enabled.  |
+|                        | * ``off`` - internal invariant checks are          |
+|                        |   disabled. The resulting executable will run      |
+|                        |   faster than a regular debug build.               |
++------------------------+----------------------------------------------------+
+| ``debug-symbols``      | * ``on`` - default for debug builds. This setting  |
+|                        |   is useful for building release builds with       |
+|                        |   symbols.                                         |
+|                        | * ``off`` - default for release builds.            |
++------------------------+----------------------------------------------------+
 
 The ``variant`` feature is *implicit*, which means you don't need to specify
 the name of the feature, just the value.
@@ -527,6 +540,13 @@ defines you can use to control the build.
 | ``TORRENT_DISABLE_RESOLVE_COUNTRIES`` | Defining this will disable the ability to       |
 |                                       | resolve countries of origin for peer IPs.       |
 +---------------------------------------+-------------------------------------------------+
+| ``TORRENT_DISABLE_INVARIANT_CHECKS``  | This will disable internal invariant checks in  |
+|                                       | libtorrent. The invariant checks can sometime   |
+|                                       | be quite expensive, they typically don't scale  |
+|                                       | very well. This option can be used to still     |
+|                                       | build in debug mode, with asserts enabled, but  |
+|                                       | make the resulting executable faster.           |
++---------------------------------------+-------------------------------------------------+
 
 
 If you experience that libtorrent uses unreasonable amounts of cpu, it will

include/libtorrent/invariant_check.hpp

@@ -66,7 +66,7 @@ namespace libtorrent
 	}
 }
 
-#ifndef NDEBUG
+#if !defined NDEBUG && !defined TORRENT_DISABLE_INVARIANT_CHECKS
 #define INVARIANT_CHECK \
 	invariant_checker const& _invariant_check = make_invariant_checker(*this); \
 	(void)_invariant_check; \