From c71cb26a9e841888f52e4bfcaad94c8f8ecb4fdb Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <thomas@codesourcery.com>
Date: Tue, 9 Nov 2021 10:55:15 +0100
Subject: [PATCH] Get rid of infinite recursion for 'typedef' used with
GTY-marked 'gcc/diagnostic-spec.h:nowarn_map' [PR101204, PR103157]
Reproduced with clang version 10.0.0-4ubuntu1:
gtype-desc.c:11333:1: warning: all paths through this function will call itself [-Winfinite-recursion]
... as well as some GCC's '-O2 -fdump-tree-optimized':
void gt_pch_nx(int_hash<unsigned int, 0u, 4294967295u>*, gt_pointer_operator, void*) ([...])
{
<bb 2>:
<bb 3>:
goto <bb 3>;
}
That three-arguments 'gt_pch_nx' function as well as two one-argument
'gt_ggc_mx', 'gt_pch_nx' functions now turn empty:
[...]
void
-gt_ggc_mx (int_hash<location_t,0,UINT_MAX>& x_r ATTRIBUTE_UNUSED)
+gt_ggc_mx (struct xint_hash_t& x_r ATTRIBUTE_UNUSED)
{
- int_hash<location_t,0,UINT_MAX> * ATTRIBUTE_UNUSED x = &x_r;
- gt_ggc_mx (&((*x)));
+ struct xint_hash_t * ATTRIBUTE_UNUSED x = &x_r;
}
[...]
void
-gt_pch_nx (int_hash<location_t,0,UINT_MAX>& x_r ATTRIBUTE_UNUSED)
+gt_pch_nx (struct xint_hash_t& x_r ATTRIBUTE_UNUSED)
{
- int_hash<location_t,0,UINT_MAX> * ATTRIBUTE_UNUSED x = &x_r;
- gt_pch_nx (&((*x)));
+ struct xint_hash_t * ATTRIBUTE_UNUSED x = &x_r;
}
[...]
void
-gt_pch_nx (int_hash<location_t,0,UINT_MAX>* x ATTRIBUTE_UNUSED,
+gt_pch_nx (struct xint_hash_t* x ATTRIBUTE_UNUSED,
ATTRIBUTE_UNUSED gt_pointer_operator op,
ATTRIBUTE_UNUSED void *cookie)
{
- gt_pch_nx (&((*x)), op, cookie);
}
[...]
gcc/
PR middle-end/101204
PR other/103157
* diagnostic-spec.h (typedef xint_hash_t): Turn into...
(struct xint_hash_t): ... this.
* doc/gty.texi: Update.
---
gcc/diagnostic-spec.h | 6 +++++-
gcc/doc/gty.texi | 8 ++++++++
2 files changed, 13 insertions(+), 1 deletion(-)
@@ -130,7 +130,11 @@ operator!= (const nowarn_spec_t &lhs, const nowarn_spec_t &rhs)
return !(lhs == rhs);
}
-typedef int_hash <location_t, 0, UINT_MAX> xint_hash_t;
+/* Per PR103157 "'gengtype': 'typedef' causing infinite-recursion code to be
+ generated", don't use
+ typedef int_hash<location_t, 0, UINT_MAX> xint_hash_t;
+ here. */
+struct xint_hash_t : int_hash<location_t, 0, UINT_MAX> {};
typedef hash_map<xint_hash_t, nowarn_spec_t> xint_hash_map_t;
/* A mapping from a 'location_t' to the warning spec set for it. */
@@ -64,6 +64,14 @@ The parser understands simple typedefs such as
@code{typedef int @var{name};}.
These don't need to be marked.
+However, in combination with GTY, avoid using typedefs such as
+@code{typedef int_hash<@dots{}> @var{name};}
+for these generate infinite-recursion code.
+See @uref{https://gcc.gnu.org/PR103157,PR103157}.
+Instead, you may use
+@code{struct @var{name} : int_hash<@dots{}> @{@};},
+for example.
+
Since @code{gengtype}'s understanding of C++ is limited, there are
several constructs and declarations that are not supported inside
classes/structures marked for automatic GC code generation. The
--
2.33.0