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<a name="GIMPLE_005fDEBUG-1"></a>
<h4 class="subsection">12.8.7 <code>GIMPLE_DEBUG</code></h4>
<a name="index-GIMPLE_005fDEBUG"></a>
<a name="index-GIMPLE_005fDEBUG_005fBIND"></a>
<a name="index-GIMPLE_005fDEBUG_005fBEGIN_005fSTMT"></a>
<a name="index-GIMPLE_005fDEBUG_005fINLINE_005fENTRY"></a>

<dl>
<dt><a name="index-_002agimple_005fbuild_005fdebug_005fbind"></a>GIMPLE function: <em>gdebug</em> <strong>*gimple_build_debug_bind</strong> <em>(tree var, tree value, gimple stmt)</em></dt>
<dd><p>Build a <code>GIMPLE_DEBUG</code> statement with <code>GIMPLE_DEBUG_BIND</code>
<code>subcode</code>.  The effect of this statement is to tell debug
information generation machinery that the value of user variable
<code>var</code> is given by <code>value</code> at that point, and to remain with
that value until <code>var</code> runs out of scope, a
dynamically-subsequent debug bind statement overrides the binding, or
conflicting values reach a control flow merge point.  Even if
components of the <code>value</code> expression change afterwards, the
variable is supposed to retain the same value, though not necessarily
the same location.
</p>
<p>It is expected that <code>var</code> be most often a tree for automatic user
variables (<code>VAR_DECL</code> or <code>PARM_DECL</code>) that satisfy the
requirements for gimple registers, but it may also be a tree for a
scalarized component of a user variable (<code>ARRAY_REF</code>,
<code>COMPONENT_REF</code>), or a debug temporary (<code>DEBUG_EXPR_DECL</code>).
</p>
<p>As for <code>value</code>, it can be an arbitrary tree expression, but it is
recommended that it be in a suitable form for a gimple assignment
<code>RHS</code>.  It is not expected that user variables that could appear
as <code>var</code> ever appear in <code>value</code>, because in the latter we&rsquo;d
have their <code>SSA_NAME</code>s instead, but even if they were not in SSA
form, user variables appearing in <code>value</code> are to be regarded as
part of the executable code space, whereas those in <code>var</code> are to
be regarded as part of the source code space.  There is no way to
refer to the value bound to a user variable within a <code>value</code>
expression.
</p>
<p>If <code>value</code> is <code>GIMPLE_DEBUG_BIND_NOVALUE</code>, debug information
generation machinery is informed that the variable <code>var</code> is
unbound, i.e., that its value is indeterminate, which sometimes means
it is really unavailable, and other times that the compiler could not
keep track of it.
</p>
<p>Block and location information for the newly-created stmt are
taken from <code>stmt</code>, if given.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fdebug_005fbind_005fget_005fvar"></a>GIMPLE function: <em>tree</em> <strong>gimple_debug_bind_get_var</strong> <em>(gimple stmt)</em></dt>
<dd><p>Return the user variable <var>var</var> that is bound at <code>stmt</code>.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fdebug_005fbind_005fget_005fvalue"></a>GIMPLE function: <em>tree</em> <strong>gimple_debug_bind_get_value</strong> <em>(gimple stmt)</em></dt>
<dd><p>Return the value expression that is bound to a user variable at
<code>stmt</code>.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fdebug_005fbind_005fget_005fvalue_005fptr"></a>GIMPLE function: <em>tree *</em> <strong>gimple_debug_bind_get_value_ptr</strong> <em>(gimple stmt)</em></dt>
<dd><p>Return a pointer to the value expression that is bound to a user
variable at <code>stmt</code>.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fdebug_005fbind_005fset_005fvar"></a>GIMPLE function: <em>void</em> <strong>gimple_debug_bind_set_var</strong> <em>(gimple stmt, tree var)</em></dt>
<dd><p>Modify the user variable bound at <code>stmt</code> to <var>var</var>.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fdebug_005fbind_005fset_005fvalue"></a>GIMPLE function: <em>void</em> <strong>gimple_debug_bind_set_value</strong> <em>(gimple stmt, tree var)</em></dt>
<dd><p>Modify the value bound to the user variable bound at <code>stmt</code> to
<var>value</var>.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fdebug_005fbind_005freset_005fvalue"></a>GIMPLE function: <em>void</em> <strong>gimple_debug_bind_reset_value</strong> <em>(gimple stmt)</em></dt>
<dd><p>Modify the value bound to the user variable bound at <code>stmt</code> so
that the variable becomes unbound.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fdebug_005fbind_005fhas_005fvalue_005fp"></a>GIMPLE function: <em>bool</em> <strong>gimple_debug_bind_has_value_p</strong> <em>(gimple stmt)</em></dt>
<dd><p>Return <code>TRUE</code> if <code>stmt</code> binds a user variable to a value,
and <code>FALSE</code> if it unbinds the variable.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fbuild_005fdebug_005fbegin_005fstmt"></a>GIMPLE function: <em>gimple</em> <strong>gimple_build_debug_begin_stmt</strong> <em>(tree block, location_t location)</em></dt>
<dd><p>Build a <code>GIMPLE_DEBUG</code> statement with
<code>GIMPLE_DEBUG_BEGIN_STMT</code> <code>subcode</code>.  The effect of this
statement is to tell debug information generation machinery that the
user statement at the given <code>location</code> and <code>block</code> starts at
the point at which the statement is inserted.  The intent is that side
effects (e.g. variable bindings) of all prior user statements are
observable, and that none of the side effects of subsequent user
statements are.
</p></dd></dl>

<dl>
<dt><a name="index-gimple_005fbuild_005fdebug_005finline_005fentry"></a>GIMPLE function: <em>gimple</em> <strong>gimple_build_debug_inline_entry</strong> <em>(tree block, location_t location)</em></dt>
<dd><p>Build a <code>GIMPLE_DEBUG</code> statement with
<code>GIMPLE_DEBUG_INLINE_ENTRY</code> <code>subcode</code>.  The effect of this
statement is to tell debug information generation machinery that a
function call at <code>location</code> underwent inline substitution, that
<code>block</code> is the enclosing lexical block created for the
substitution, and that at the point of the program in which the stmt is
inserted, all parameters for the inlined function are bound to the
respective arguments, and none of the side effects of its stmts are
observable.
</p></dd></dl>

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