[gcc/devel/c++-contracts] c++: contracts postcondition id redeclaration

[gcc/devel/c++-contracts] c++: contracts postcondition id redeclaration

[Jason Merrill]

https://gcc.gnu.org/g:6e2be2d05164c927b04a384844d181d2114219ad

commit 6e2be2d05164c927b04a384844d181d2114219ad
Author: Jason Merrill <jason@redhat.com>
Date:   Mon Jul 5 17:04:41 2021 -0400

    c++: contracts postcondition id redeclaration
    
    We were crashing because the variable for the postcondition identifier was
    referring to the second declaration after it was ggc_freed.  When we copy
    the contracts from newdecl back to olddecl, we need to update the dummy
    return variable's DECL_CONTEXT.
    
    And the use of newdecl/olddecl here didn't match either the comment or the
    use of those names in the call from duplicate_decls.
    
    gcc/cp/ChangeLog:
    
            * contracts.cc (copy_contract_attributes): Swap parameter names.
            Call rebuild_postconditions.

Diff:
---
 gcc/cp/contracts.cc | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/gcc/cp/contracts.cc b/gcc/cp/contracts.cc
index 4df25a104d2..c343fcf3f3b 100644
--- a/gcc/cp/contracts.cc
+++ b/gcc/cp/contracts.cc
@@ -896,17 +896,20 @@ tree splice_out_contracts (tree attributes)
 
 /* Copy contract attributes from NEWDECL onto the attribute list of OLDDECL.  */
 
-void copy_contract_attributes (tree newdecl, tree olddecl)
+void copy_contract_attributes (tree olddecl, tree newdecl)
 {
   tree attrs = NULL_TREE;
-  for (tree c = DECL_CONTRACTS (olddecl); c; c = TREE_CHAIN (c))
+  for (tree c = DECL_CONTRACTS (newdecl); c; c = TREE_CHAIN (c))
     {
       if (!cxx_contract_attribute_p (c))
 	continue;
       attrs = tree_cons (TREE_PURPOSE (c), TREE_VALUE (c), attrs);
     }
-  attrs = chainon (DECL_ATTRIBUTES (newdecl), nreverse (attrs));
-  DECL_ATTRIBUTES (newdecl) = attrs;
+  attrs = chainon (DECL_ATTRIBUTES (olddecl), nreverse (attrs));
+  DECL_ATTRIBUTES (olddecl) = attrs;
+
+  /* And update DECL_CONTEXT of the postcondition result identifier.  */
+  rebuild_postconditions (olddecl);
 }
 
 /* Returns the parameter corresponding to the return value of a guarded