PR c++/23099

	* cp-tree.h (saved_scope): Add skip_evaluation.
	* decl.c (start_decl): Use DECL_INITIALIZED_IN_CLASS_P, not
	DECL_INITIAL, to determine whether or not a static data member was
	initialized in the class-specifier.
	(cp_finish_decl): Add comment.
	* init.c (integral_constant_value): Subtitute into the
	initializers for static data members in	templates.
	* name-lookup.c (push_to_top_level): Save skip_evaluation.
	(pop_from_top_level): Restore it.
	* pt.c (instantiate_class_template): Do not substitute into the
	intializers of static data members when instantiating a class.
	(regenerate_decl_from_template): Simplify.
	(instantiate_decl): Tidy.  Substitute into the initializer for a
	static data member even when the definition of the data member is
	not available.

	PR c++/23099
	* g++.dg/init/member1.C: Make sure erroneous static data member
	definitions are required.
	* g++.dg/template/static13.C: New test.
	* g++.dg/template/static14.C: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@103604 138bc75d-0d04-0410-961f-82ee72b054a4

10 files changed, 134 insertions, 42 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4c2c72ed066..40513367888 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,22 @@
+2005-08-28  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23099
+	* cp-tree.h (saved_scope): Add skip_evaluation.
+	* decl.c (start_decl): Use DECL_INITIALIZED_IN_CLASS_P, not
+	DECL_INITIAL, to determine whether or not a static data member was
+	initialized in the class-specifier.
+	(cp_finish_decl): Add comment.
+	* init.c (integral_constant_value): Subtitute into the
+	initializers for static data members in	templates.
+	* name-lookup.c (push_to_top_level): Save skip_evaluation.
+	(pop_from_top_level): Restore it.
+	* pt.c (instantiate_class_template): Do not substitute into the
+	intializers of static data members when instantiating a class.
+	(regenerate_decl_from_template): Simplify.
+	(instantiate_decl): Tidy.  Substitute into the initializer for a
+	static data member even when the definition of the data member is
+	not available.
+
 2005-08-26  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/19004
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 17e074dc99f..e8d5fe77049 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -655,6 +655,7 @@ struct saved_scope GTY(())
   int x_processing_specialization;
   bool x_processing_explicit_instantiation;
   int need_pop_function_context;
+  bool skip_evaluation;
 
   struct stmt_tree_s x_stmt_tree;
 
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 4199b241b9b..a32be093c74 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -3716,7 +3716,8 @@ start_decl (const cp_declarator *declarator,
 		 declaration will have DECL_EXTERNAL set, but will have an
 		 initialization.  Thus, duplicate_decls won't warn
 		 about this situation, and so we check here.  */
-	      if (DECL_INITIAL (decl) && DECL_INITIAL (field))
+	      if (DECL_INITIAL (decl) 
+		  && DECL_INITIALIZED_IN_CLASS_P (field))
 		error ("duplicate initialization of %qD", decl);
 	      if (duplicate_decls (decl, field))
 		decl = field;
@@ -4921,10 +4922,20 @@ cp_finish_decl (tree decl, tree init, tree asmspec_tree, int flags)
 		     "initialized", decl);
 	      init = NULL_TREE;
 	    }
+
+	  /* Check that the initializer for a static data member was a
+	     constant.  Althouh we check in the parser that the
+	     initializer is an integral constant expression, we do not
+	     simplify division-by-zero at the point at which it
+	     occurs.  Therefore, in:
+
+	       struct S { static const int i = 7 / 0; };
+	       
+	     we issue an error at this point.  It would
+	     probably be better to forbid division by zero in
+	     integral constant expressions.  */
 	  if (DECL_EXTERNAL (decl) && init)
 	    {
-	      /* The static data member cannot be initialized by a
-		 non-constant when being declared.  */
 	      error ("%qD cannot be initialized by a non-constant expression"
 		     " when being declared", decl);
 	      DECL_INITIALIZED_IN_CLASS_P (decl) = 0;
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 690e35f8913..8a8dc782ca3 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -1572,12 +1572,25 @@ integral_constant_value (tree decl)
 	      /* And so are variables with a 'const' type -- unless they
 		 are also 'volatile'.  */
 	      && CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (decl))
-	      && DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl)))
-	 && DECL_INITIAL (decl)
-	 && DECL_INITIAL (decl) != error_mark_node
-	 && TREE_TYPE (DECL_INITIAL (decl))
-	 && INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (DECL_INITIAL (decl))))
-    decl = DECL_INITIAL (decl);
+	      && DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl))))
+    {
+      tree init;
+      /* If DECL is a static data member in a template class, we must
+	 instantiate it here.  The initializer for the static data
+	 member is not processed until needed; we need it now.  */ 
+      mark_used (decl);
+      init = DECL_INITIAL (decl);
+      /* If we are currently processing a template, the
+	 initializer for a static data member may not be dependent,
+	 but it is not folded until instantiation time.  */
+      if (init)
+	init = fold_non_dependent_expr (init);
+      if (!(init || init == error_mark_node)
+	  || !TREE_TYPE (init)
+	  || !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (init)))
+	break;
+      decl = init;
+    }
   return decl;
 }
 
diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index 2beb3e7eaec..7270a9dd112 100644
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -4872,12 +4872,14 @@ push_to_top_level (void)
   s->bindings = b;
   s->need_pop_function_context = need_pop;
   s->function_decl = current_function_decl;
+  s->skip_evaluation = skip_evaluation;
 
   scope_chain = s;
   current_function_decl = NULL_TREE;
   current_lang_base = VEC_alloc (tree, gc, 10);
   current_lang_name = lang_name_cplusplus;
   current_namespace = global_namespace;
+  skip_evaluation = 0;
   timevar_pop (TV_NAME_LOOKUP);
 }
 
@@ -4909,6 +4911,7 @@ pop_from_top_level (void)
   if (s->need_pop_function_context)
     pop_function_context_from (NULL_TREE);
   current_function_decl = s->function_decl;
+  skip_evaluation = s->skip_evaluation;
   timevar_pop (TV_NAME_LOOKUP);
 }
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 386dc2ff0d7..773d8650891 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -5699,17 +5699,22 @@ instantiate_class_template (tree type)
 		    --processing_template_decl;
 		  if (TREE_CODE (r) == VAR_DECL)
 		    {
-		      tree init;
-
-		      if (DECL_INITIALIZED_IN_CLASS_P (r))
-			init = tsubst_expr (DECL_INITIAL (t), args,
-					    tf_error | tf_warning, NULL_TREE);
-		      else
-			init = NULL_TREE;
-
-		      finish_static_data_member_decl
-			(r, init, /*asmspec_tree=*/NULL_TREE, /*flags=*/0);
-
+		      /* In [temp.inst]:
+
+			   [t]he initialization (and any associated
+			   side-effects) of a static data member does
+			   not occur unless the static data member is
+			   itself used in a way that requires the
+			   definition of the static data member to
+			   exist.  
+
+			 Therefore, we do not substitute into the
+		         initialized for the static data member here.  */
+		      finish_static_data_member_decl 
+			(r, 
+			 /*init=*/NULL_TREE, 
+			 /*asmspec_tree=*/NULL_TREE, 
+			 /*flags=*/0);
 		      if (DECL_INITIALIZED_IN_CLASS_P (r))
 			check_static_variable_definition (r, TREE_TYPE (r));
 		    }
@@ -11278,13 +11283,9 @@ regenerate_decl_from_template (tree decl, tree tmpl)
 	DECL_INLINE (decl) = 1;
     }
   else if (TREE_CODE (decl) == VAR_DECL)
-    {
-      if (!DECL_INITIALIZED_IN_CLASS_P (decl)
-	  && DECL_INITIAL (code_pattern))
-	DECL_INITIAL (decl) =
-	  tsubst_expr (DECL_INITIAL (code_pattern), args,
-		       tf_error, DECL_TI_TEMPLATE (decl));
-    }
+    DECL_INITIAL (decl) =
+      tsubst_expr (DECL_INITIAL (code_pattern), args,
+		   tf_error, DECL_TI_TEMPLATE (decl));
   else
     gcc_unreachable ();
 
@@ -11367,7 +11368,7 @@ instantiate_decl (tree d, int defer_ok,
   tree code_pattern;
   tree spec;
   tree gen_tmpl;
-  int pattern_defined;
+  bool pattern_defined;
   int need_push;
   location_t saved_loc = input_location;
 
@@ -11415,9 +11416,6 @@ instantiate_decl (tree d, int defer_ok,
 
   timevar_push (TV_PARSE);
 
-  /* We may be in the middle of deferred access check.  Disable it now.  */
-  push_deferring_access_checks (dk_no_deferred);
-
   /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
      for the instantiation.  */
   td = template_for_substitution (d);
@@ -11437,6 +11435,10 @@ instantiate_decl (tree d, int defer_ok,
     pattern_defined = (DECL_SAVED_TREE (code_pattern) != NULL_TREE);
   else
     pattern_defined = ! DECL_IN_AGGR_P (code_pattern);
+
+  /* We may be in the middle of deferred access check.  Disable it now.  */
+  push_deferring_access_checks (dk_no_deferred);
+
   /* Unless an explicit instantiation directive has already determined
      the linkage of D, remember that a definition is available for
      this entity.  */
@@ -11486,12 +11488,6 @@ instantiate_decl (tree d, int defer_ok,
       pop_access_scope (d);
     }
 
-  /* We should have set up DECL_INITIAL in instantiate_class_template
-     for in-class definitions of static data members.  */
-  gcc_assert (!(TREE_CODE (d) == VAR_DECL
-		&& DECL_INITIALIZED_IN_CLASS_P (d)
-		&& DECL_INITIAL (d) == NULL_TREE));
-
   /* Do not instantiate templates that we know will be defined
      elsewhere.  */
   if (DECL_INTERFACE_KNOWN (d)
@@ -11504,6 +11500,20 @@ instantiate_decl (tree d, int defer_ok,
      because it's used by add_pending_template.  */
   else if (! pattern_defined || defer_ok)
     {
+      /* The definition of the static data member is now required so
+	 we must substitute the initializer.  */
+      if (TREE_CODE (d) == VAR_DECL
+	  && !DECL_INITIAL (d) 
+	  && DECL_INITIAL (code_pattern))
+	{
+	  push_nested_class (DECL_CONTEXT (d));
+	  DECL_INITIAL (d)
+	    = tsubst_expr (DECL_INITIAL (code_pattern), 
+			   args,
+			   tf_error | tf_warning, NULL_TREE);
+	  pop_nested_class ();
+	}
+
       input_location = saved_loc;
 
       if (at_eof && !pattern_defined
@@ -11570,10 +11580,7 @@ instantiate_decl (tree d, int defer_ok,
 
       /* Enter the scope of D so that access-checking works correctly.  */
       push_nested_class (DECL_CONTEXT (d));
-      cp_finish_decl (d,
-		      (!DECL_INITIALIZED_IN_CLASS_P (d)
-		       ? DECL_INITIAL (d) : NULL_TREE),
-		      NULL_TREE, 0);
+      cp_finish_decl (d, DECL_INITIAL (d), NULL_TREE, 0);
       pop_nested_class ();
     }
   else if (TREE_CODE (d) == FUNCTION_DECL)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 229e55b3701..c896f324496 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2005-08-28  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23099
+	* g++.dg/init/member1.C: Make sure erroneous static data member
+	definitions are required.
+	* g++.dg/template/static13.C: New test.
+	* g++.dg/template/static14.C: Likewise.
+
 2005-08-29  Jakub Jelinek  <jakub@redhat.com>
 
 	* gcc.target/i386/pr23575.c: Use -msse2 instead of
diff --git a/gcc/testsuite/g++.dg/init/member1.C b/gcc/testsuite/g++.dg/init/member1.C
index 1c89d5a1d43..aededf23e7b 100644
--- a/gcc/testsuite/g++.dg/init/member1.C
+++ b/gcc/testsuite/g++.dg/init/member1.C
@@ -11,8 +11,11 @@ template<int> struct B {};
 template<typename T> struct C
 {
   static const int i = A<T>::i;  // { dg-error "incomplete" }
-  static const int j = i;      // { dg-error "initialized by a non-const" }
+  static const int j = i;
   B<j> b;  // { dg-error "not a valid template arg" }
 };
 
 C<int> c;
+
+int i = C<int>::i;
+int j = C<int>::j;
diff --git a/gcc/testsuite/g++.dg/template/static13.C b/gcc/testsuite/g++.dg/template/static13.C
new file mode 100644
index 00000000000..c43f5554739
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/static13.C
@@ -0,0 +1,14 @@
+// PR c++/23099
+
+struct Base {
+  int x;
+};
+
+template <typename T>
+struct A {
+  static const int N = sizeof(static_cast<Base*>(T()));
+};
+
+struct Derived : Base {
+  A<Derived*> a;
+};
diff --git a/gcc/testsuite/g++.dg/template/static14.C b/gcc/testsuite/g++.dg/template/static14.C
new file mode 100644
index 00000000000..5bc0e731ac3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/static14.C
@@ -0,0 +1,13 @@
+struct Base {
+  int x;
+};
+
+template <typename T>
+struct A {
+  static const int N = sizeof(static_cast<Base*>(T()));
+  int a[N];
+};
+
+struct Derived : Base {
+  A<Derived*> a;
+};