Add documentation about how to debug non-stable PNaCl pexes in Pepper 35.

native_client_sdk/doc_generated/devguide/devcycle/debugging.html

Index: native_client_sdk/doc_generated/devguide/devcycle/debugging.html
diff --git a/native_client_sdk/doc_generated/devguide/devcycle/debugging.html b/native_client_sdk/doc_generated/devguide/devcycle/debugging.html
index 696ca552b4cb475a0ac8aa2cbf4da6e0b926cfdd..2c8b5ebfef1d58244a0afeee31d532020dd13a73 100644
--- a/native_client_sdk/doc_generated/devguide/devcycle/debugging.html
+++ b/native_client_sdk/doc_generated/devguide/devcycle/debugging.html
@@ -7,34 +7,35 @@ and measure your application&#8217;s performance.</p>
 <div class="contents local" id="table-of-contents" style="display: none">
 <p class="topic-title first">Table Of Contents</p>
 <ul class="small-gap">
-<li><p class="first"><a class="reference internal" href="#diagnostic-information" id="id1">Diagnostic information</a></p>
+<li><p class="first"><a class="reference internal" href="#diagnostic-information" id="id2">Diagnostic information</a></p>
 <ul class="small-gap">
-<li><a class="reference internal" href="#viewing-process-statistics-with-the-task-manager" id="id2">Viewing process statistics with the task manager</a></li>
-<li><a class="reference internal" href="#controlling-the-level-of-native-client-error-and-warning-messages" id="id3">Controlling the level of Native Client error and warning messages</a></li>
+<li><a class="reference internal" href="#viewing-process-statistics-with-the-task-manager" id="id3">Viewing process statistics with the task manager</a></li>
+<li><a class="reference internal" href="#controlling-the-level-of-native-client-error-and-warning-messages" id="id4">Controlling the level of Native Client error and warning messages</a></li>
 </ul>
 </li>
-<li><p class="first"><a class="reference internal" href="#basic-debugging" id="id4">Basic debugging</a></p>
+<li><p class="first"><a class="reference internal" href="#basic-debugging" id="id5">Basic debugging</a></p>
 <ul class="small-gap">
-<li><a class="reference internal" href="#writing-messages-to-the-javascript-console" id="id5">Writing messages to the JavaScript console</a></li>
-<li><p class="first"><a class="reference internal" href="#debugging-with-printf" id="id6">Debugging with printf</a></p>
+<li><a class="reference internal" href="#writing-messages-to-the-javascript-console" id="id6">Writing messages to the JavaScript console</a></li>
+<li><p class="first"><a class="reference internal" href="#debugging-with-printf" id="id7">Debugging with printf</a></p>
 <ul class="small-gap">
-<li><a class="reference internal" href="#redirecting-output-to-log-files" id="id7">Redirecting output to log files</a></li>
-<li><a class="reference internal" href="#redirecting-output-to-the-javascript-console" id="id8">Redirecting output to the JavaScript console</a></li>
+<li><a class="reference internal" href="#redirecting-output-to-log-files" id="id8">Redirecting output to log files</a></li>
+<li><a class="reference internal" href="#redirecting-output-to-the-javascript-console" id="id9">Redirecting output to the JavaScript console</a></li>
 </ul>
 </li>
-<li><a class="reference internal" href="#logging-calls-to-pepper-interfaces" id="id9">Logging calls to Pepper interfaces</a></li>
-<li><a class="reference internal" href="#debugging-with-visual-studio" id="id10">Debugging with Visual Studio</a></li>
-<li><p class="first"><a class="reference internal" href="#debugging-with-nacl-gdb" id="id11">Debugging with nacl-gdb</a></p>
+<li><a class="reference internal" href="#logging-calls-to-pepper-interfaces" id="id10">Logging calls to Pepper interfaces</a></li>
+<li><a class="reference internal" href="#debugging-with-visual-studio" id="id11">Debugging with Visual Studio</a></li>
+<li><p class="first"><a class="reference internal" href="#debugging-with-nacl-gdb" id="id12">Debugging with nacl-gdb</a></p>
 <ul class="small-gap">
-<li><a class="reference internal" href="#debugging-pnacl-pexes" id="id12">Debugging PNaCl pexes</a></li>
-<li><a class="reference internal" href="#running-nacl-gdb" id="id13">Running nacl-gdb</a></li>
+<li><a class="reference internal" href="#debugging-pnacl-pexes-with-pepper-35" id="id13">Debugging PNaCl pexes (with Pepper 35+)</a></li>
+<li><a class="reference internal" href="#debugging-pnacl-pexes-with-older-pepper-toolchains" id="id14">Debugging PNaCl pexes (with older Pepper toolchains)</a></li>
+<li><a class="reference internal" href="#running-nacl-gdb" id="id15">Running nacl-gdb</a></li>
 </ul>
 </li>
 </ul>
 </li>
-<li><p class="first"><a class="reference internal" href="#debugging-with-other-tools" id="id14">Debugging with other tools</a></p>
+<li><p class="first"><a class="reference internal" href="#debugging-with-other-tools" id="id16">Debugging with other tools</a></p>
 <ul class="small-gap">
-<li><a class="reference internal" href="#open-source-profiling-tools" id="id15">Open source profiling tools</a></li>
+<li><a class="reference internal" href="#open-source-profiling-tools" id="id17">Open source profiling tools</a></li>
 </ul>
 </li>
 </ul>
@@ -209,17 +210,61 @@ is the platform of your development machine: <code>win</code>, <code>mac</code>,
 whether built using newlib or glibc for x86-32, x86-64 or ARM.  In the SDK,
 <code>i686-nacl-gdb</code> is an alias for <code>x86_64-nacl-gdb</code>, and the <code>newlib</code>
 and <code>glibc</code> toolchains both contain the same version of GDB.</p>
-<section id="debugging-pnacl-pexes">
-<h4 id="debugging-pnacl-pexes">Debugging PNaCl pexes</h4>
+<section id="debugging-pnacl-pexes-with-pepper-35">
+<h4 id="debugging-pnacl-pexes-with-pepper-35">Debugging PNaCl pexes (with Pepper 35+)</h4>
+<p>If you want to use GDB to debug a program that is compiled with the PNaCl
+toolchain, you must have a copy of the pexe from <strong>before</strong> running
+<code>pnacl-finalize</code>. The <code>pnacl-finalize</code> tool converts LLVM bitcode
+to the stable PNaCl bitcode format, but it also strips out debug
+metadata, which we need for debugging.</p>
+<p><strong>Note</strong> unlike the finalized copy of the pexe, the non-finalized debug copy
+is not considered stable. This means that a debug copy of the PNaCl
+application created by a Pepper N SDK is only guaranteed to run
+with a matching Chrome version N. If the version of the debug bitcode pexe
+does not match that of Chrome then the translation process may fail, and
+you will see and error message in the JavaScript console.</p>
+<p>Also, make sure you are passing the <code>-g</code> <a class="reference internal" href="/native-client/devguide/devcycle/building.html#compile-flags"><em>compile option</em></a> to <code>pnacl-clang</code> to enable generating debugging info.
+You might also want to omit <code>-O2</code> from the compile-time and link-time
+options, otherwise GDB not might be able to print variables&#8217; values when
+debugging (this is more of a problem with the PNaCl/LLVM toolchain than
+with GCC).</p>
+<p>Once you have built a non-stable debug copy of the pexe, list the URL of
+that copy in your application&#8217;s manifest file:</p>
+<pre class="prettyprint">
+{
+  &quot;program&quot;: {
+    &quot;pnacl-translate&quot;: {
+      &quot;url&quot;: &quot;release_version.pexe&quot;,
+      &quot;optlevel&quot;: 2
+    },
+    &quot;pnacl-debug&quot;: {
+      &quot;url&quot;: &quot;debug_version.bc&quot;,
+      &quot;optlevel&quot;: 0
+    }
+  }
+}
+</pre>
+<p>Copy the <code>debug_version.bc</code> and <code>nmf</code> files to the location that
+your local web server serves files from.</p>
+<p>When you run Chrome with <code>--enable-nacl-debug</code>, Chrome will translate
+and run the <code>debug_version.bc</code> instead of <code>release_version.pexe</code>.
+Once the debug version is loaded, you are ready to <a class="reference internal" href="#running-nacl-gdb"><em>run nacl-gdb</em></a></p>
+<p>Whether you publish the NMF file containing the debug URL to the release
+web server, is up to you. One reason to avoid publishing the debug URL
+is that it is only guaranteed to work for the Chrome version that matches
+the SDK version. Developers who may have left the <code>--enable-nacl-debug</code>
+flag turned on may end up loading the debug copy of your application
+(which may or may not work, depending on their version of Chrome).</p>
+</section><section id="debugging-pnacl-pexes-with-older-pepper-toolchains">
+<h4 id="debugging-pnacl-pexes-with-older-pepper-toolchains">Debugging PNaCl pexes (with older Pepper toolchains)</h4>
 <p>If you want to use GDB to debug a program that is compiled with the PNaCl
 toolchain, you must convert the <code>pexe</code> file to a <code>nexe</code>.  (You can skip
-this step if you are using the GCC toolchain.)</p>
+this step if you are using the GCC toolchain, or if you are using
+pepper 35 or later.)</p>
 <ul class="small-gap">
 <li>Firstly, make sure you are passing the <code>-g</code> <a class="reference internal" href="/native-client/devguide/devcycle/building.html#compile-flags"><em>compile option</em></a> to <code>pnacl-clang</code> to enable generating debugging info.
 You might also want to omit <code>-O2</code> from the compile-time and link-time
-options, otherwise GDB not might be able to print variables&#8217; values when
-debugging (this is more of a problem with the PNaCl/LLVM toolchain than
-with GCC).</li>
+options.</li>
 <li><p class="first">Secondly, use <code>pnacl-translate</code> to convert your <code>pexe</code> to one or more
 <code>nexe</code> files.  For example:</p>
 <pre>
@@ -260,7 +305,7 @@ might find it easier to translate the <code>pexe</code> to both <code>nexe</code
 formats as described above.
 </aside>
 </section><section id="running-nacl-gdb">
-<h4 id="running-nacl-gdb">Running nacl-gdb</h4>
+<span id="id1"></span><h4 id="running-nacl-gdb"><span id="id1"></span>Running nacl-gdb</h4>
 <p>Before you start using nacl-gdb, make sure you can <a class="reference internal" href="/native-client/devguide/devcycle/building.html"><em>build</em></a> your
 module and <a class="reference internal" href="/native-client/devguide/devcycle/running.html"><em>run</em></a> your application normally. This will verify
 that you have created all the required <a class="reference internal" href="/native-client/devguide/coding/application-structure.html"><em>application parts</em></a> (.html, .nmf, and .nexe files, shared
@@ -312,6 +357,18 @@ directory so that changes you make to Chrome in your debugging session do
 not affect your personal Chrome data (history, cookies, bookmarks, themes,
 and settings).</p>
 </dd>
+<dt><code>--nacl-debug-mask=&lt;nmf_url_mask1,nmf_url_mask2,...&gt;</code></dt>
+<dd><p class="first last">Specifies a set of debug mask patterns. This allows you to selectively
+choose to debug certain applications and not debug others. For example,
+if you only want to debug the NMF files for your applications at
+<code>https://example.com/app</code>, and no other PNaCl applications found
+on the web, specify <code>--nacl-debug-mask=https://example.com/app/*.nmf</code>.
+This helps accidentally debugging other PNaCl applications if you like
+to leave the <code>--enable-nacl-debug</code> flag turned on.
+The pattern language for the mask follows <a class="reference external" href="http://developer.chrome.com/extensions/match_patterns">chrome extension match patterns</a>.
+The pattern set can be inverted by prefixing the pattern set with
+the <code>!</code> character.</p>
+</dd>
 <dt><code>&lt;URL&gt;</code></dt>
 <dd><p class="first last">Specifies the URL Chrome should open when it launches. The local server
 that comes with the SDK listens on port 5103 by default, so the URL when
@@ -337,33 +394,62 @@ cd &lt;NACL_SDK_ROOT&gt;/examples/hello_world_gles
 (gdb)
 </pre>
 </li>
-<li><p class="first">Run the following three commands from the gdb command line:</p>
+<li><p class="first">For debugging PNaCl pexes run the following gdb command lines
+(skip to the next item if you are using NaCl instead of PNaCl):</p>
+<pre class="prettyprint">
+(gdb) target remote localhost:4014
+(gdb) remote get nexe &lt;path-to-save-translated-nexe-with-debug-info&gt;
+(gdb) file &lt;path-to-save-translated-nexe-with-debug-info&gt;
+(gdb) remote get irt &lt;path-to-save-NaCl-integrated-runtime&gt;
+(gdb) nacl-irt &lt;path-to-saved-NaCl-integrated-runtime&gt;
+</pre>
+</li>
+<li><p class="first">For NaCl nexes, run the following commands from the gdb command line:</p>
 <pre class="prettyprint">
-(gdb) nacl-manifest &lt;path-to-your-.nmf-file&gt;
-(gdb) nacl-irt &lt;path-to-Chrome-NaCl-integrated-runtime&gt;
 (gdb) target remote localhost:4014
+(gdb) nacl-manifest &lt;path-to-your-.nmf-file&gt;
+(gdb) remote get irt &lt;path-to-save-NaCl-integrated-runtime&gt;
+(gdb) nacl-irt &lt;path-to-saved-NaCl-integrated-runtime&gt;
 </pre>
-<p>These commands are described below:</p>
+</li>
+<li><p class="first">The command used for PNaCl and NaCl are described below:</p>
 <dl class="docutils">
+<dt><code>target remote localhost:4014</code></dt>
+<dd><p class="first last">Tells the debugger how to connect to the debug stub in the Native Client
+application loader. This connection occurs through TCP port 4014 (note
+that this port is distinct from the port which the local web server uses
+to listen for incoming requests, typically port 5103). If you are
+debugging multiple applications at the same time, the loader may choose
+a port that is different from the default 4014 port. See the Chrome
+task manager for the debug port.</p>
+</dd>
+<dt><code>remote get nexe &lt;path&gt;</code></dt>
+<dd><p class="first last">This saves the application&#8217;s main executable (nexe) to <code>&lt;path&gt;</code>.
+For PNaCl, this provides a convenient way to access the nexe that is
+a <strong>result</strong> of translating your pexe. This can then be loaded with
+the <code>file &lt;path&gt;</code> command.</p>
+</dd>
 <dt><code>nacl-manifest &lt;path&gt;</code></dt>
-<dd><p class="first last">Tells the debugger about your Native Client application by pointing it to
-the application&#8217;s manifest (.nmf) file. The manifest file lists your
-application&#8217;s executable (.nexe) files, as well as any libraries that are
-linked with the application dynamically.</p>
+<dd><p class="first last">For NaCl (not PNaCl), this tells the debugger where to find your
+application&#8217;s executable (.nexe) files. The application&#8217;s manifest
+(.nmf) file lists your application&#8217;s executable files, as well as any
+libraries that are linked with the application dynamically.</p>
 </dd>
-<dt><code>nacl-irt &lt;path&gt;</code></dt>
-<dd><p class="first last">Tells the debugger where to find the Native Client Integrated Runtime
-(IRT). The IRT is located in the same directory as the Chrome executable,
+<dt><code>remote get irt &lt;path&gt;</code></dt>
+<dd><p class="first last">This saves the Native Client Integrated Runtime (IRT). Normally,
+the IRT is located in the same directory as the Chrome executable,
 or in a subdirectory named after the Chrome version. For example, if
 you&#8217;re running Chrome canary on Windows, the path to the IRT typically
 looks something like <code>C:/Users/&lt;username&gt;/AppData/Local/Google/Chrome
-SxS/Application/23.0.1247.1/nacl_irt_x86_64.nexe</code>.</p>
+SxS/Application/23.0.1247.1/nacl_irt_x86_64.nexe</code>.
+The <code>remote get irt &lt;path&gt;</code> saves that to the current working
+directory so that you do not need to find where exactly the IRT
+is stored alongside Chrome.</p>
 </dd>
-<dt><code>target remote localhost:4014</code></dt>
-<dd><p class="first last">Tells the debugger how to connect to the debug stub in the Native Client
-application loader. This connection occurs through TCP port 4014 (note
-that this port is distinct from the port which the local web server uses
-to listen for incoming requests, typically port 5103).</p>
+<dt><code>nacl-irt &lt;path&gt;</code></dt>
+<dd><p class="first last">Tells the debugger where to find the Native Client Integrated Runtime
+(IRT). <code>&lt;path&gt;</code> can either be the location of the copy saved by
+<code>remote get irt &lt;path&gt;</code> or the copy that is installed alongside Chrome.</p>
 </dd>
 </dl>
 <p>A couple of notes on how to specify path names in the nacl-gdb commands
@@ -381,9 +467,9 @@ quotation marks around the path.</p>
 <p>As an example, here is a what these nacl-gdb commands might look like on
 Windows:</p>
 <pre class="prettyprint">
+target remote localhost:4014
 nacl-manifest &quot;C:/&lt;NACL_SDK_ROOT&gt;/examples/hello_world_gles/newlib/Debug/hello_world_gles.nmf&quot;
 nacl-irt &quot;C:/Users/&lt;username&gt;/AppData/Local/Google/Chrome SxS/Application/23.0.1247.1/nacl_irt_x86_64.nexe&quot;
-target remote localhost:4014
 </pre>
 <p>To save yourself some typing, you can put put these nacl-gdb commands in a
 script file, and execute the file when you run nacl-gdb, like so:</p>