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116 lines
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116 lines
5.7 KiB
HTML
4 years ago
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<title>Statement and operand traversals - GNU Compiler Collection (GCC) Internals</title>
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<link rel="up" href="GIMPLE.html#GIMPLE" title="GIMPLE">
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<link rel="prev" href="Adding-a-new-GIMPLE-statement-code.html#Adding-a-new-GIMPLE-statement-code" title="Adding a new GIMPLE statement code">
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Copyright (C) 1988-2015 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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(see below). A copy of the license is included in the section entitled
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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<div class="node">
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<a name="Statement-and-operand-traversals"></a>
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<p>
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Previous: <a rel="previous" accesskey="p" href="Adding-a-new-GIMPLE-statement-code.html#Adding-a-new-GIMPLE-statement-code">Adding a new GIMPLE statement code</a>,
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Up: <a rel="up" accesskey="u" href="GIMPLE.html#GIMPLE">GIMPLE</a>
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<hr>
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</div>
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<h3 class="section">11.12 Statement and operand traversals</h3>
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<p><a name="index-Statement-and-operand-traversals-2501"></a>
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There are two functions available for walking statements and
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sequences: <code>walk_gimple_stmt</code> and <code>walk_gimple_seq</code>,
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accordingly, and a third function for walking the operands in a
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statement: <code>walk_gimple_op</code>.
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<div class="defun">
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— GIMPLE function: tree <b>walk_gimple_stmt</b> (<var>gimple_stmt_iterator *gsi, walk_stmt_fn callback_stmt, walk_tree_fn callback_op, struct walk_stmt_info *wi</var>)<var><a name="index-walk_005fgimple_005fstmt-2502"></a></var><br>
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<blockquote><p>This function is used to walk the current statement in <code>GSI</code>,
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optionally using traversal state stored in <code>WI</code>. If <code>WI</code> is <code>NULL</code>, no
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state is kept during the traversal.
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<p>The callback <code>CALLBACK_STMT</code> is called. If <code>CALLBACK_STMT</code> returns
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true, it means that the callback function has handled all the
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operands of the statement and it is not necessary to walk its
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operands.
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<p>If <code>CALLBACK_STMT</code> is <code>NULL</code> or it returns false, <code>CALLBACK_OP</code> is
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called on each operand of the statement via <code>walk_gimple_op</code>. If
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<code>walk_gimple_op</code> returns non-<code>NULL</code> for any operand, the remaining
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operands are not scanned.
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<p>The return value is that returned by the last call to
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<code>walk_gimple_op</code>, or <code>NULL_TREE</code> if no <code>CALLBACK_OP</code> is specified.
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</p></blockquote></div>
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<div class="defun">
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— GIMPLE function: tree <b>walk_gimple_op</b> (<var>gimple stmt, walk_tree_fn callback_op, struct walk_stmt_info *wi</var>)<var><a name="index-walk_005fgimple_005fop-2503"></a></var><br>
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<blockquote><p>Use this function to walk the operands of statement <code>STMT</code>. Every
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operand is walked via <code>walk_tree</code> with optional state information
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in <code>WI</code>.
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<p><code>CALLBACK_OP</code> is called on each operand of <code>STMT</code> via <code>walk_tree</code>.
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Additional parameters to <code>walk_tree</code> must be stored in <code>WI</code>. For
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each operand <code>OP</code>, <code>walk_tree</code> is called as:
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<pre class="smallexample"> walk_tree (&<code>OP</code>, <code>CALLBACK_OP</code>, <code>WI</code>, <code>PSET</code>)
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</pre>
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<p>If <code>CALLBACK_OP</code> returns non-<code>NULL</code> for an operand, the remaining
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operands are not scanned. The return value is that returned by
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the last call to <code>walk_tree</code>, or <code>NULL_TREE</code> if no <code>CALLBACK_OP</code> is
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specified.
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</p></blockquote></div>
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<div class="defun">
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— GIMPLE function: tree <b>walk_gimple_seq</b> (<var>gimple_seq seq, walk_stmt_fn callback_stmt, walk_tree_fn callback_op, struct walk_stmt_info *wi</var>)<var><a name="index-walk_005fgimple_005fseq-2504"></a></var><br>
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<blockquote><p>This function walks all the statements in the sequence <code>SEQ</code>
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calling <code>walk_gimple_stmt</code> on each one. <code>WI</code> is as in
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<code>walk_gimple_stmt</code>. If <code>walk_gimple_stmt</code> returns non-<code>NULL</code>, the walk
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is stopped and the value returned. Otherwise, all the statements
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are walked and <code>NULL_TREE</code> returned.
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</p></blockquote></div>
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<!-- Copyright (C) 2004-2015 Free Software Foundation, Inc. -->
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