PR ipa/92799 - ICE on a weakref function definition followed by a declaration

gcc/testsuite/ChangeLog:

	PR ipa/92799
	* gcc.dg/attr-weakref-5.c: New test.

gcc/ChangeLog:

	PR ipa/92799
	* cgraphunit.c (process_function_and_variable_attributes): Also
	complain about weakref function definitions and drop all effects
	of the attribute.

gcc/ChangeLog

@@ -1,3 +1,10 @@
+2020-03-18  Martin Sebor  <msebor@redhat.com>
+
+	PR ipa/92799
+	* cgraphunit.c (process_function_and_variable_attributes): Also
+	complain about weakref function definitions and drop all effects
+	of the attribute.
+
 2020-03-18  Andre Vieira  <andre.simoesdiasvieira@arm.com>
             Mihail Ionescu  <mihail.ionescu@arm.com>
             Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

gcc/cgraphunit.c

@@ -861,14 +861,23 @@ process_function_and_variable_attributes (cgraph_node *first,
 			" attribute have effect only on public objects");
 	}
       if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl))
-	  && (node->definition && !node->alias))
+	  && node->definition
+	  && (!node->alias || DECL_INITIAL (decl) != error_mark_node))
 	{
-	  warning_at (DECL_SOURCE_LOCATION (node->decl), OPT_Wattributes,
+	  /* NODE->DEFINITION && NODE->ALIAS is nonzero for valid weakref
+	     function declarations; DECL_INITIAL is non-null for invalid
+	     weakref functions that are also defined.  */
+	  warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wattributes,
 		      "%<weakref%> attribute ignored"
 		      " because function is defined");
 	  DECL_WEAK (decl) = 0;
 	  DECL_ATTRIBUTES (decl) = remove_attribute ("weakref",
 						     DECL_ATTRIBUTES (decl));
+	  DECL_ATTRIBUTES (decl) = remove_attribute ("alias",
+						     DECL_ATTRIBUTES (decl));
+	  node->alias = false;
+	  node->weakref = false;
+	  node->transparent_alias = false;
 	}
       else if (lookup_attribute ("alias", DECL_ATTRIBUTES (decl))
 	  && node->definition

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2020-03-18  Martin Sebor  <msebor@redhat.com>
+
+	PR ipa/92799
+	* gcc.dg/attr-weakref-5.c: New test.
+
 2020-03-18  Andre Vieira  <andre.simoesdiasvieira@arm.com>
             Mihail Ionescu  <mihail.ionescu@arm.com>
             Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

gcc/testsuite/gcc.dg/attr-weakref-5.c

@@ -0,0 +1,31 @@
+/* PR middle-end/92799 - ICE on a weakref function definition followed
+   by a declaration
+   { dg-do compile }
+   { dg-options "-Wall" } */
+
+static __attribute__ ((weakref ("bar"))) void f0 (void) { }   // { dg-warning "'weakref' attribute ignored because function is defined" }
+
+extern void f0 (void);
+
+void* use_f0 (void) { return f0; }
+
+
+static __attribute__ ((weakref ("bar"))) void f1 (void) { }   // { dg-warning "'weakref' attribute ignored because function is defined" }
+
+static void f1 (void);
+
+void* use_f1 (void) { return f1; }
+
+
+static __attribute__ ((weakref ("bar"))) void f2 (void);
+
+static void f2 (void) { }                                     // { dg-error "redefinition" }
+
+void* use_f2 (void) { return f2; }
+
+
+static __attribute__ ((weakref ("bar"))) void f3 (void);
+
+void f3 (void) { }                                            // { dg-error "redefinition" }
+
+void* use_f3 (void) { return f3; }