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semantics.c (prune_unused_decls): New function.

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* cp/semantics.c (prune_unused_decls): New function.
	(finish_stmt_tree): Call it via walk_tree.

From-SVN: r36056
This commit is contained in:
Zack Weinberg 2000-08-29 22:13:20 +00:00 committed by Zack Weinberg
parent 63ad61edae
commit 7efcf4662e
2 changed files with 64 additions and 0 deletions
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5
gcc/cp/ChangeLog
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@ -1,3 +1,8 @@
2000-08-29 Zack Weinberg <zack@wolery.cumb.org>
* cp/semantics.c (prune_unused_decls): New function.
(finish_stmt_tree): Call it via walk_tree.
2000-08-29 Zack Weinberg <zack@wolery.cumb.org>
* class.c (build_secondary_vtable): Constify a char *.

59
gcc/cp/semantics.c
View File

@ -48,6 +48,7 @@
static tree maybe_convert_cond PARAMS ((tree));
static tree simplify_aggr_init_exprs_r PARAMS ((tree *, int *, void *));
static tree prune_unused_decls PARAMS ((tree *, int *, void *));
static void deferred_type_access_control PARAMS ((void));
static void emit_associated_thunks PARAMS ((tree));
@ -2241,6 +2242,57 @@ finish_typeof (expr)
return TREE_TYPE (expr);
}
/* Remove declarations of internal variables that are not used from a
stmt tree. To qualify, the variable must have a name and must have
a zero DECL_SOURCE_LINE. We tried to remove all variables for
which TREE_USED was false, but it turns out that there's tons of
variables for which TREE_USED is false but that are still in fact
used. */
static tree
prune_unused_decls (tp, walk_subtrees, data)
tree *tp;
int *walk_subtrees ATTRIBUTE_UNUSED;
void *data ATTRIBUTE_UNUSED;
{
tree t = *tp;
if (t == NULL_TREE)
{
*walk_subtrees = 0;
return NULL_TREE;
}
if (TREE_CODE (t) == DECL_STMT)
{
tree d = DECL_STMT_DECL (t);
if (!TREE_USED (d) && DECL_NAME (d) && DECL_SOURCE_LINE (d) == 0)
{
*tp = TREE_CHAIN (t);
/* Recurse on the new value of tp, otherwise we will skip
the next statement. */
return prune_unused_decls (tp, walk_subtrees, data);
}
}
else if (TREE_CODE (t) == BLOCK)
{
/* walk_tree doesn't inspect BLOCK_VARS, so we must do it by hand. */
tree *vp;
for (vp = &BLOCK_VARS (t); *vp; )
{
tree v = *vp;
if (! TREE_USED (v) && DECL_NAME (v) && DECL_SOURCE_LINE (v) == 0)
*vp = TREE_CHAIN (v); /* drop */
else
vp = &TREE_CHAIN (v); /* advance */
}
if (BLOCK_VARS (t) == NULL_TREE)
TREE_USED (t) = 0;
}
return NULL_TREE;
}
/* Create an empty statement tree rooted at T. */
void
@ -2262,12 +2314,19 @@ finish_stmt_tree (t)
tree *t;
{
tree stmt;
int old_lineno;
/* Remove the fake extra statement added in begin_stmt_tree. */
stmt = TREE_CHAIN (*t);
*t = stmt;
SET_LAST_STMT (NULL_TREE);
/* Remove unused decls from the stmt tree. walk_tree messes with
the line number, so save/restore it. */
old_lineno = lineno;
walk_tree (t, prune_unused_decls, 0);
lineno = old_lineno;
if (cfun)
{
/* The line-number recorded in the outermost statement in a function