@@ -2957,6 +2957,17 @@ duplicate_decls (tree newdecl, tree olddecl)
{
/* Avoid `unused variable' and other warnings for OLDDECL. */
suppress_warning (olddecl, OPT_Wunused);
+ /* If the types are completely different, poison them both with
+ error_mark_node. */
+ if (TREE_CODE (TREE_TYPE (newdecl)) != TREE_CODE (TREE_TYPE (olddecl))
+ && olddecl != error_mark_node
+ && seen_error())
+ {
+ if (TREE_CODE (olddecl) != FUNCTION_DECL)
+ TREE_TYPE (olddecl) = error_mark_node;
+ if (TREE_CODE (newdecl) != FUNCTION_DECL)
+ TREE_TYPE (newdecl) = error_mark_node;
+ }
return false;
}
@@ -12209,7 +12220,7 @@ free_attr_access_data ()
attr_access::free_lang_data (attrs);
tree fntype = TREE_TYPE (n->decl);
- if (!fntype)
+ if (!fntype || fntype == error_mark_node)
continue;
tree attrs = TYPE_ATTRIBUTES (fntype);
if (!attrs)
@@ -4,12 +4,13 @@
int f (void)
{
extern float v;
-
+/* { dg-message "note: previous declaration" "previous declaration" { target *-*-* } .-1 } */
return (v > 0.0f);
}
extern int t;
+/* { dg-message "note: previous declaration" "previous declaration" { target *-*-* } .-1 } */
typedef float t; /* { dg-error "redeclared as different kind of symbol" } */
-t v = 4.5f;
+t v = 4.5f; /* { dg-error "conflicting types" } */
This patch fixes an ICE during error-recovery regression in the C front-end. The symptom is that the middle-end's sanity checking assertions fail during gimplification when being asked to increment an array, which is non-sense. The issue is that the C-front end has detected the type mismatch and reported an error to the user, but hasn't provided any indication of this to the middle-end, simply passing bogus trees that the optimizers recognize as invalid. This appears to be a frequently reported ICE with 94730, 94731, 101036 and 101365 all marked as duplicates. I believe the correct (polite) fix is to mark the mismatched types as problematic/dubious in the front-end, when the error is spotted, so that the middle-end has a heads-up and can be a little more forgiving. This patch to c-decl.c's duplicate_decls sets (both) mismatched types to error_mark_node if they are significantly different, and we've issued an error message. Alas, this is too punitive for FUNCTION_DECLs where we store return types, parameter lists, parameter types and attributes in the type, but fortunately the middle-end is already more cautious about trusting possibly suspect function types. This fix required one minor change to the testsuite, typedef-var-2.c where after conflicting type definitions, we now no longer assume that the (first or) second definition is the correct one. This change only affects the behaviour after seen_error(), so should be relatively safe. This patch has been tested on x86_64-pc-linux-gnu with "make bootstrap" and "make -k check" with no new failures. Ok for mainline? 2020-08-31 Roger Sayle <roger@nextmovesoftware.com> gcc/c/ChangeLog PR c/79412 * c-decl.c (duplicate_decls): On significant mismatches, mark the types of both (non-function) decls as error_mark_node, so that the middle-end can see the code is malformed. (free_attr_access_data): Don't process if the type has been set to error_mark_node. gcc/testsuite/ChangeLog PR c/79412 * gcc.dg/pr79412.c: New test case. * gcc.dg/typedef-var-2.c: Update expeted errors. Roger -- /* { dg-do compile } */ /* { dg-options "-O2" } */ int a; /* { dg-message "note: previous declaration" "previous declaration" { target *-*-* } .-1 } */ void fn1 () { a++; } int a[] = {2}; /* { dg-error "conflicting types" } */