You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
240 lines
10 KiB
HTML
240 lines
10 KiB
HTML
<html lang="en">
|
|
<head>
|
|
<title>Plugin API - GNU Compiler Collection (GCC) Internals</title>
|
|
<meta http-equiv="Content-Type" content="text/html">
|
|
<meta name="description" content="GNU Compiler Collection (GCC) Internals">
|
|
<meta name="generator" content="makeinfo 4.13">
|
|
<link title="Top" rel="start" href="index.html#Top">
|
|
<link rel="up" href="Plugins.html#Plugins" title="Plugins">
|
|
<link rel="prev" href="Plugins-loading.html#Plugins-loading" title="Plugins loading">
|
|
<link rel="next" href="Plugins-pass.html#Plugins-pass" title="Plugins pass">
|
|
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
|
|
<!--
|
|
Copyright (C) 1988-2015 Free Software Foundation, Inc.
|
|
|
|
Permission is granted to copy, distribute and/or modify this document
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
|
any later version published by the Free Software Foundation; with the
|
|
Invariant Sections being ``Funding Free Software'', the Front-Cover
|
|
Texts being (a) (see below), and with the Back-Cover Texts being (b)
|
|
(see below). A copy of the license is included in the section entitled
|
|
``GNU Free Documentation License''.
|
|
|
|
(a) The FSF's Front-Cover Text is:
|
|
|
|
A GNU Manual
|
|
|
|
(b) The FSF's Back-Cover Text is:
|
|
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
|
software. Copies published by the Free Software Foundation raise
|
|
funds for GNU development.-->
|
|
<meta http-equiv="Content-Style-Type" content="text/css">
|
|
<style type="text/css"><!--
|
|
pre.display { font-family:inherit }
|
|
pre.format { font-family:inherit }
|
|
pre.smalldisplay { font-family:inherit; font-size:smaller }
|
|
pre.smallformat { font-family:inherit; font-size:smaller }
|
|
pre.smallexample { font-size:smaller }
|
|
pre.smalllisp { font-size:smaller }
|
|
span.sc { font-variant:small-caps }
|
|
span.roman { font-family:serif; font-weight:normal; }
|
|
span.sansserif { font-family:sans-serif; font-weight:normal; }
|
|
--></style>
|
|
</head>
|
|
<body>
|
|
<div class="node">
|
|
<a name="Plugin-API"></a>
|
|
<p>
|
|
Next: <a rel="next" accesskey="n" href="Plugins-pass.html#Plugins-pass">Plugins pass</a>,
|
|
Previous: <a rel="previous" accesskey="p" href="Plugins-loading.html#Plugins-loading">Plugins loading</a>,
|
|
Up: <a rel="up" accesskey="u" href="Plugins.html#Plugins">Plugins</a>
|
|
<hr>
|
|
</div>
|
|
|
|
<h3 class="section">23.2 Plugin API</h3>
|
|
|
|
<p>Plugins are activated by the compiler at specific events as defined in
|
|
<samp><span class="file">gcc-plugin.h</span></samp>. For each event of interest, the plugin should
|
|
call <code>register_callback</code> specifying the name of the event and
|
|
address of the callback function that will handle that event.
|
|
|
|
<p>The header <samp><span class="file">gcc-plugin.h</span></samp> must be the first gcc header to be included.
|
|
|
|
<h4 class="subsection">23.2.1 Plugin license check</h4>
|
|
|
|
<p>Every plugin should define the global symbol <code>plugin_is_GPL_compatible</code>
|
|
to assert that it has been licensed under a GPL-compatible license.
|
|
If this symbol does not exist, the compiler will emit a fatal error
|
|
and exit with the error message:
|
|
|
|
<pre class="smallexample"> fatal error: plugin <var>name</var> is not licensed under a GPL-compatible license
|
|
<var>name</var>: undefined symbol: plugin_is_GPL_compatible
|
|
compilation terminated
|
|
</pre>
|
|
<p>The declared type of the symbol should be int, to match a forward declaration
|
|
in <samp><span class="file">gcc-plugin.h</span></samp> that suppresses C++ mangling. It does not need to be in
|
|
any allocated section, though. The compiler merely asserts that
|
|
the symbol exists in the global scope. Something like this is enough:
|
|
|
|
<pre class="smallexample"> int plugin_is_GPL_compatible;
|
|
</pre>
|
|
<h4 class="subsection">23.2.2 Plugin initialization</h4>
|
|
|
|
<p>Every plugin should export a function called <code>plugin_init</code> that
|
|
is called right after the plugin is loaded. This function is
|
|
responsible for registering all the callbacks required by the plugin
|
|
and do any other required initialization.
|
|
|
|
<p>This function is called from <code>compile_file</code> right before invoking
|
|
the parser. The arguments to <code>plugin_init</code> are:
|
|
|
|
<ul>
|
|
<li><code>plugin_info</code>: Plugin invocation information.
|
|
<li><code>version</code>: GCC version.
|
|
</ul>
|
|
|
|
<p>The <code>plugin_info</code> struct is defined as follows:
|
|
|
|
<pre class="smallexample"> struct plugin_name_args
|
|
{
|
|
char *base_name; /* Short name of the plugin
|
|
(filename without .so suffix). */
|
|
const char *full_name; /* Path to the plugin as specified with
|
|
-fplugin=. */
|
|
int argc; /* Number of arguments specified with
|
|
-fplugin-arg-.... */
|
|
struct plugin_argument *argv; /* Array of ARGC key-value pairs. */
|
|
const char *version; /* Version string provided by plugin. */
|
|
const char *help; /* Help string provided by plugin. */
|
|
}
|
|
</pre>
|
|
<p>If initialization fails, <code>plugin_init</code> must return a non-zero
|
|
value. Otherwise, it should return 0.
|
|
|
|
<p>The version of the GCC compiler loading the plugin is described by the
|
|
following structure:
|
|
|
|
<pre class="smallexample"> struct plugin_gcc_version
|
|
{
|
|
const char *basever;
|
|
const char *datestamp;
|
|
const char *devphase;
|
|
const char *revision;
|
|
const char *configuration_arguments;
|
|
};
|
|
</pre>
|
|
<p>The function <code>plugin_default_version_check</code> takes two pointers to
|
|
such structure and compare them field by field. It can be used by the
|
|
plugin's <code>plugin_init</code> function.
|
|
|
|
<p>The version of GCC used to compile the plugin can be found in the symbol
|
|
<code>gcc_version</code> defined in the header <samp><span class="file">plugin-version.h</span></samp>. The
|
|
recommended version check to perform looks like
|
|
|
|
<pre class="smallexample"> #include "plugin-version.h"
|
|
...
|
|
|
|
int
|
|
plugin_init (struct plugin_name_args *plugin_info,
|
|
struct plugin_gcc_version *version)
|
|
{
|
|
if (!plugin_default_version_check (version, &gcc_version))
|
|
return 1;
|
|
|
|
}
|
|
</pre>
|
|
<p>but you can also check the individual fields if you want a less strict check.
|
|
|
|
<h4 class="subsection">23.2.3 Plugin callbacks</h4>
|
|
|
|
<p>Callback functions have the following prototype:
|
|
|
|
<pre class="smallexample"> /* The prototype for a plugin callback function.
|
|
gcc_data - event-specific data provided by GCC
|
|
user_data - plugin-specific data provided by the plug-in. */
|
|
typedef void (*plugin_callback_func)(void *gcc_data, void *user_data);
|
|
</pre>
|
|
<p>Callbacks can be invoked at the following pre-determined events:
|
|
|
|
<pre class="smallexample"> enum plugin_event
|
|
{
|
|
PLUGIN_PASS_MANAGER_SETUP, /* To hook into pass manager. */
|
|
PLUGIN_FINISH_TYPE, /* After finishing parsing a type. */
|
|
PLUGIN_FINISH_DECL, /* After finishing parsing a declaration. */
|
|
PLUGIN_FINISH_UNIT, /* Useful for summary processing. */
|
|
PLUGIN_PRE_GENERICIZE, /* Allows to see low level AST in C and C++ frontends. */
|
|
PLUGIN_FINISH, /* Called before GCC exits. */
|
|
PLUGIN_INFO, /* Information about the plugin. */
|
|
PLUGIN_GGC_START, /* Called at start of GCC Garbage Collection. */
|
|
PLUGIN_GGC_MARKING, /* Extend the GGC marking. */
|
|
PLUGIN_GGC_END, /* Called at end of GGC. */
|
|
PLUGIN_REGISTER_GGC_ROOTS, /* Register an extra GGC root table. */
|
|
PLUGIN_ATTRIBUTES, /* Called during attribute registration */
|
|
PLUGIN_START_UNIT, /* Called before processing a translation unit. */
|
|
PLUGIN_PRAGMAS, /* Called during pragma registration. */
|
|
/* Called before first pass from all_passes. */
|
|
PLUGIN_ALL_PASSES_START,
|
|
/* Called after last pass from all_passes. */
|
|
PLUGIN_ALL_PASSES_END,
|
|
/* Called before first ipa pass. */
|
|
PLUGIN_ALL_IPA_PASSES_START,
|
|
/* Called after last ipa pass. */
|
|
PLUGIN_ALL_IPA_PASSES_END,
|
|
/* Allows to override pass gate decision for current_pass. */
|
|
PLUGIN_OVERRIDE_GATE,
|
|
/* Called before executing a pass. */
|
|
PLUGIN_PASS_EXECUTION,
|
|
/* Called before executing subpasses of a GIMPLE_PASS in
|
|
execute_ipa_pass_list. */
|
|
PLUGIN_EARLY_GIMPLE_PASSES_START,
|
|
/* Called after executing subpasses of a GIMPLE_PASS in
|
|
execute_ipa_pass_list. */
|
|
PLUGIN_EARLY_GIMPLE_PASSES_END,
|
|
/* Called when a pass is first instantiated. */
|
|
PLUGIN_NEW_PASS,
|
|
/* Called when a file is #include-d or given via the #line directive.
|
|
This could happen many times. The event data is the included file path,
|
|
as a const char* pointer. */
|
|
PLUGIN_INCLUDE_FILE,
|
|
|
|
PLUGIN_EVENT_FIRST_DYNAMIC /* Dummy event used for indexing callback
|
|
array. */
|
|
};
|
|
</pre>
|
|
<p>In addition, plugins can also look up the enumerator of a named event,
|
|
and / or generate new events dynamically, by calling the function
|
|
<code>get_named_event_id</code>.
|
|
|
|
<p>To register a callback, the plugin calls <code>register_callback</code> with
|
|
the arguments:
|
|
|
|
<ul>
|
|
<li><code>char *name</code>: Plugin name.
|
|
<li><code>int event</code>: The event code.
|
|
<li><code>plugin_callback_func callback</code>: The function that handles <code>event</code>.
|
|
<li><code>void *user_data</code>: Pointer to plugin-specific data.
|
|
</ul>
|
|
|
|
<p>For the <i>PLUGIN_PASS_MANAGER_SETUP</i>, <i>PLUGIN_INFO</i>, and
|
|
<i>PLUGIN_REGISTER_GGC_ROOTS</i> pseudo-events the <code>callback</code> should be null,
|
|
and the <code>user_data</code> is specific.
|
|
|
|
<p>When the <i>PLUGIN_PRAGMAS</i> event is triggered (with a null pointer as
|
|
data from GCC), plugins may register their own pragmas. Notice that
|
|
pragmas are not available from <samp><span class="file">lto1</span></samp>, so plugins used with
|
|
<code>-flto</code> option to GCC during link-time optimization cannot use
|
|
pragmas and do not even see functions like <code>c_register_pragma</code> or
|
|
<code>pragma_lex</code>.
|
|
|
|
<p>The <i>PLUGIN_INCLUDE_FILE</i> event, with a <code>const char*</code> file path as
|
|
GCC data, is triggered for processing of <code>#include</code> or
|
|
<code>#line</code> directives.
|
|
|
|
<p>The <i>PLUGIN_FINISH</i> event is the last time that plugins can call GCC
|
|
functions, notably emit diagnostics with <code>warning</code>, <code>error</code>
|
|
etc.
|
|
|
|
</body></html>
|
|
|