Re: [PATCH] libgccjit: Fix infinite recursion in gt_ggc_mx_lang_tree_node

[Antoni Boucher <bouanto@zoho.com>]

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Sorry, forgot to attach the patch.

Here it is.

On Thu, 2022-06-02 at 21:20 -0400, Antoni Boucher via Jit wrote:
> Hi.
> The attached patch fix bug 105827:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105827
> 
> I'm not sure how to test this, so please share ideas.
> 
> Thanks for the review.


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From 609153a39921b8e9aa1934da131575bb64881d67 Mon Sep 17 00:00:00 2001
From: Antoni Boucher <bouanto@zoho.com>
Date: Thu, 2 Jun 2022 21:14:06 -0400
Subject: [PATCH] libgccjit: Fix infinite recursion in gt_ggc_mx_lang_tree_node

2022-06-02  Antoni Boucher  <bouanto@zoho.com>

gcc/jit/
	PR target/105827
	* dummy-frontend.cc: Fix lang_tree_node.
	* jit-common.h: New function (jit_tree_chain_next) used by
	lang_tree_node.
---
 gcc/jit/dummy-frontend.cc | 13 +++++++------
 gcc/jit/jit-common.h      | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/gcc/jit/dummy-frontend.cc b/gcc/jit/dummy-frontend.cc
index 84ff359bfe3..8bb5d03d630 100644
--- a/gcc/jit/dummy-frontend.cc
+++ b/gcc/jit/dummy-frontend.cc
@@ -506,13 +506,14 @@ struct GTY(()) lang_identifier
 
 /* The resulting tree type.  */
 
+/* See lang_tree_node in gcc/c/c-decl.cc.  */
 union GTY((desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
-	   chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))
-lang_tree_node
-{
-  union tree_node GTY((tag ("0"),
-		       desc ("tree_node_structure (&%h)"))) generic;
-  struct lang_identifier GTY((tag ("1"))) identifier;
+       chain_next ("(union lang_tree_node *) jit_tree_chain_next (&%h.generic)"))) lang_tree_node
+ {
+  union tree_node GTY ((tag ("0"),
+			desc ("tree_node_structure (&%h)")))
+    generic;
+  struct lang_identifier GTY ((tag ("1"))) identifier;
 };
 
 /* We don't use language_function.  */
diff --git a/gcc/jit/jit-common.h b/gcc/jit/jit-common.h
index 3ff7447fbf3..50580358a1f 100644
--- a/gcc/jit/jit-common.h
+++ b/gcc/jit/jit-common.h
@@ -93,6 +93,21 @@ const int NUM_GCC_JIT_TYPES = GCC_JIT_TYPE_INT128_T + 1;
 
    End of comment for inclusion in the docs.  */
 
+/* See c_tree_chain_next in gcc/c-family/c-common.h.  */
+static inline tree
+jit_tree_chain_next (tree t)
+{
+  /* TREE_CHAIN of a type is TYPE_STUB_DECL, which is different
+     kind of object, never a long chain of nodes.  Prefer
+     TYPE_NEXT_VARIANT for types.  */
+  if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPE_COMMON))
+    return TYPE_NEXT_VARIANT (t);
+  /* Otherwise, if there is TREE_CHAIN, return it.  */
+  if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_COMMON))
+    return TREE_CHAIN (t);
+  return NULL;
+}
+
 namespace gcc {
 
 namespace jit {
-- 
2.26.2.7.g19db9cfb68.dirty