[Ada] Fix compiler crash on function returning array at -O

Message ID 2446908.YqmE466GVv@polaris
State New
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Series
  • [Ada] Fix compiler crash on function returning array at -O
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Commit Message

Eric Botcazou May 28, 2019, 8:09 a.m.
This is a regression present on all active branches.  The compiler segfaults 
on a function returning an array variable declared locally and used in a 
grandchild function but not in its parent function (which is a child of the 
first function).

Tested on x86_64-suse-linux, applied on all active branches.


2019-05-28  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/trans.c (walk_nesting_tree): New static function.
	(finalize_nrv): Use it to walk the entire nesting tree.


2019-05-28  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/opt79.ad[sb]: New test.

-- 
Eric Botcazou

Patch

Index: gcc-interface/trans.c
===================================================================
--- gcc-interface/trans.c	(revision 271659)
+++ gcc-interface/trans.c	(working copy)
@@ -4280,6 +4280,20 @@  finalize_nrv_unc_r (tree *tp, int *walk_
   return NULL_TREE;
 }
 
+/* Apply FUNC to all the sub-trees of nested functions in NODE.  FUNC is called
+   with the DATA and the address of each sub-tree.  If FUNC returns a non-NULL
+   value, the traversal is stopped.  */
+
+static void
+walk_nesting_tree (struct cgraph_node *node, walk_tree_fn func, void *data)
+{
+  for (node = node->nested; node; node = node->next_nested)
+    {
+      walk_tree_without_duplicates (&DECL_SAVED_TREE (node->decl), func, data);
+      walk_nesting_tree (node, func, data);
+    }
+}
+
 /* Finalize the Named Return Value optimization for FNDECL.  The NRV bitmap
    contains the candidates for Named Return Value and OTHER is a list of
    the other return values.  GNAT_RET is a representative return node.  */
@@ -4287,7 +4301,6 @@  finalize_nrv_unc_r (tree *tp, int *walk_
 static void
 finalize_nrv (tree fndecl, bitmap nrv, vec<tree, va_gc> *other, Node_Id gnat_ret)
 {
-  struct cgraph_node *node;
   struct nrv_data data;
   walk_tree_fn func;
   unsigned int i;
@@ -4308,10 +4321,7 @@  finalize_nrv (tree fndecl, bitmap nrv, v
     return;
 
   /* Prune also the candidates that are referenced by nested functions.  */
-  node = cgraph_node::get_create (fndecl);
-  for (node = node->nested; node; node = node->next_nested)
-    walk_tree_without_duplicates (&DECL_SAVED_TREE (node->decl), prune_nrv_r,
-				  &data);
+  walk_nesting_tree (cgraph_node::get_create (fndecl), prune_nrv_r, &data);
   if (bitmap_empty_p (nrv))
     return;