libgccjit: Fix infinite recursion in gt_ggc_mx_lang_tree_node

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

gcc/jit/
	PR jit/105827
	* dummy-frontend.cc: Fix lang_tree_node.
	* jit-common.h: New function (jit_tree_chain_next) used by
	lang_tree_node.

diff --git a/gcc/jit/dummy-frontend.cc b/gcc/jit/dummy-frontend.cc
index 4db9bdbe413f86d071e9d23848b40135a001e5cf..faf9d036350ff083003a2954dea707c0a76cf89f 100644 (file)
--- a/gcc/jit/dummy-frontend.cc
+++ b/gcc/jit/dummy-frontend.cc
@@ -956,13 +956,15 @@ 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 845726b6cb34e0aacb13f3444af255366c1214d0..8c07f557d0cb0ad0b68ae9dbd6a4d08cb1bd6d9e 100644 (file)
--- 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_BFLOAT16 + 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 {