Bug 103157 - 'gengtype': 'typedef' causing infinite-recursion code to be generated
Summary: 'gengtype': 'typedef' causing infinite-recursion code to be generated
Status: UNCONFIRMED
Alias: None
Product: gcc
Classification: Unclassified
Component: other (show other bugs)
Version: unknown
: P3 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
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Keywords:
Depends on:
Blocks:
 
Reported: 2021-11-09 11:58 UTC by Thomas Schwinge
Modified: 2021-11-09 12:21 UTC (History)
1 user (show)

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Description Thomas Schwinge 2021-11-09 11:58:21 UTC
As we found in the course of PR101204, there are ways that certain use of 'typedef' with GTY-marked types causes 'gengtype' to generate infinite-recursion code.
Comment 1 Andrew Pinski 2021-11-09 12:01:18 UTC
There is a dup of this bug already
Comment 2 CVS Commits 2021-11-09 12:21:39 UTC
The master branch has been updated by Thomas Schwinge <tschwinge@gcc.gnu.org>:

https://gcc.gnu.org/g:c71cb26a9e841888f52e4bfcaad94c8f8ecb4fdb

commit r12-5047-gc71cb26a9e841888f52e4bfcaad94c8f8ecb4fdb
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Tue Nov 9 10:55:15 2021 +0100

    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.