re PR c++/16564 (g++ seems to go into an infinite loop after errors)

cp/
2014-09-30  Manuel López-Ibáñez  <manu@gcc.gnu.org>

       PR c++/16564
       * error.c (print_instantiation_context): Delete.
       * typeck2.c (build_x_arrow): Record location when pushing
       template instantiation.
       * pt.c (push_tinst_level): Make it a wrapper around ...
       (push_tinst_level_loc): ... this. New function. Make excessive
       template instantiation depth a fatal error. Record location. Use
       bool as return type.
       (instantiate_pending_templates): Make excessive
       template instantiation depth a fatal error.
       (problematic_instantiation_changed): Use bool as return type.
       * cp-tree.h (print_instantiation_context): Delete.
       (push_tinst_level): Update declaration.
       (problematic_instantiation_changed): Likewise.
       (push_tinst_level_loc): New.

testsuite/
2014-09-30  Manuel López-Ibáñez  <manu@gcc.gnu.org>

       PR c++/16564
       * lib/gcc.exp: Accept "fatal error:" as error prefix.
       * lib/g++.exp: Likewise.
       * lib/obj-c++.exp: Likewise.
       * lib/objc.exp: Likewise.
       * g++.dg/template/pr16564.C: New test.

2014-09-30  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/16564
	* g++.dg/cpp0x/decltype26.C: Adjust.
	* g++.dg/cpp0x/decltype28.C: Likewise.
	* g++.dg/cpp0x/decltype29.C: Likewise.
	* g++.dg/cpp0x/decltype32.C: Likewise.
	* g++.dg/cpp0x/enum11.C: Likewise.
	* g++.dg/template/arrow1.C: Likewise.
	* g++.dg/template/pr23510.C: Likewise.
	* g++.dg/template/recurse.C: Likewise.
	* g++.dg/template/recurse2.C: Likewise.
	* g++.dg/template/vtable2.C: Likewise.
	* g++.old-deja/g++.pt/infinite1.C: Likewise.

From-SVN: r215733

5 files changed, 49 insertions, 36 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 0beb997..3fe3f8d 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,21 @@
+2014-09-30  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+
+       PR c++/16564
+       * error.c (print_instantiation_context): Delete.
+       * typeck2.c (build_x_arrow): Record location when pushing
+       template instantiation.
+       * pt.c (push_tinst_level): Make it a wrapper around ...
+       (push_tinst_level_loc): ... this. New function. Make excessive
+       template instantiation depth a fatal error. Record location. Use
+       bool as return type.
+       (instantiate_pending_templates): Make excessive
+       template instantiation depth a fatal error.
+       (problematic_instantiation_changed): Use bool as return type.
+       * cp-tree.h (print_instantiation_context): Delete.
+       (push_tinst_level): Update declaration.
+       (problematic_instantiation_changed): Likewise.
+       (push_tinst_level_loc): New.
+
 2014-09-29  Richard Biener  <rguenther@suse.de>
 
 	* typeck.c (enum_cast_to_int): Use CONVERT_EXPR_P to check
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 5d8badc..f0783ab 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5418,7 +5418,6 @@ extern const char *lang_decl_name		(tree, int, bool);
 extern const char *lang_decl_dwarf_name		(tree, int, bool);
 extern const char *language_to_string		(enum languages);
 extern const char *class_key_or_enum_as_string	(tree);
-extern void print_instantiation_context		(void);
 extern void maybe_warn_variadic_templates       (void);
 extern void maybe_warn_cpp0x			(cpp0x_warn_str str);
 extern bool pedwarn_cxx98                       (location_t, int, const char *, ...) ATTRIBUTE_GCC_DIAG(3,4);
@@ -5633,7 +5632,7 @@ extern tree tsubst_copy_and_build		(tree, tree, tsubst_flags_t,
 						 tree, bool, bool);
 extern tree most_general_template		(tree);
 extern tree get_mostly_instantiated_function_type (tree);
-extern int problematic_instantiation_changed	(void);
+extern bool problematic_instantiation_changed	(void);
 extern void record_last_problematic_instantiation (void);
 extern struct tinst_level *current_instantiation(void);
 extern tree maybe_get_template_decl_from_type_decl (tree);
@@ -5661,7 +5660,8 @@ extern tree fold_non_dependent_expr_sfinae	(tree, tsubst_flags_t);
 extern bool alias_type_or_template_p            (tree);
 extern bool alias_template_specialization_p     (const_tree);
 extern bool explicit_class_specialization_p     (tree);
-extern int push_tinst_level                     (tree);
+extern bool push_tinst_level                    (tree);
+extern bool push_tinst_level_loc                (tree, location_t);
 extern void pop_tinst_level                     (void);
 extern struct tinst_level *outermost_tinst_level(void);
 extern void init_template_processing		(void);
diff --git a/gcc/cp/error.c b/gcc/cp/error.c
index a03bfe1..57f3c31 100644
--- a/gcc/cp/error.c
+++ b/gcc/cp/error.c
@@ -3360,16 +3360,6 @@ maybe_print_instantiation_context (diagnostic_context *context)
   record_last_problematic_instantiation ();
   print_instantiation_full_context (context);
 }
-
-/* Report the bare minimum context of a template instantiation.  */
-void
-print_instantiation_context (void)
-{
-  print_instantiation_partial_context
-    (global_dc, current_instantiation (), input_location);
-  pp_newline (global_dc->printer);
-  diagnostic_flush_buffer (global_dc);
-}
 
 /* Report what constexpr call(s) we're trying to expand, if any.  */
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index da8bd8f..9dd61f3 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -8347,37 +8347,37 @@ static GTY(()) struct tinst_level *last_error_tinst_level;
 /* We're starting to instantiate D; record the template instantiation context
    for diagnostics and to restore it later.  */
 
-int
+bool
 push_tinst_level (tree d)
 {
+  return push_tinst_level_loc (d, input_location);
+}
+
+/* We're starting to instantiate D; record the template instantiation context
+   at LOC for diagnostics and to restore it later.  */
+
+bool
+push_tinst_level_loc (tree d, location_t loc)
+{
   struct tinst_level *new_level;
 
   if (tinst_depth >= max_tinst_depth)
     {
-      last_error_tinst_level = current_tinst_level;
-      if (TREE_CODE (d) == TREE_LIST)
-	error ("template instantiation depth exceeds maximum of %d (use "
-	       "-ftemplate-depth= to increase the maximum) substituting %qS",
-	       max_tinst_depth, d);
-      else
-	error ("template instantiation depth exceeds maximum of %d (use "
-	       "-ftemplate-depth= to increase the maximum) instantiating %qD",
-	       max_tinst_depth, d);
-
-      print_instantiation_context ();
-
-      return 0;
+      fatal_error ("template instantiation depth exceeds maximum of %d"
+                   " (use -ftemplate-depth= to increase the maximum)",
+                   max_tinst_depth);
+      return false;
     }
 
   /* If the current instantiation caused problems, don't let it instantiate
      anything else.  Do allow deduction substitution and decls usable in
      constant expressions.  */
   if (limit_bad_template_recursion (d))
-    return 0;
+    return false;
 
   new_level = ggc_alloc<tinst_level> ();
   new_level->decl = d;
-  new_level->locus = input_location;
+  new_level->locus = loc;
   new_level->errors = errorcount+sorrycount;
   new_level->in_system_header_p = in_system_header_at (input_location);
   new_level->next = current_tinst_level;
@@ -8387,7 +8387,7 @@ push_tinst_level (tree d)
   if (GATHER_STATISTICS && (tinst_depth > depth_reached))
     depth_reached = tinst_depth;
 
-  return 1;
+  return true;
 }
 
 /* We're done instantiating this template; return to the instantiation
@@ -20291,10 +20291,10 @@ instantiate_pending_templates (int retries)
     {
       tree decl = pending_templates->tinst->decl;
 
-      error ("template instantiation depth exceeds maximum of %d"
-	     " instantiating %q+D, possibly from virtual table generation"
-	     " (use -ftemplate-depth= to increase the maximum)",
-	     max_tinst_depth, decl);
+      fatal_error ("template instantiation depth exceeds maximum of %d"
+                   " instantiating %q+D, possibly from virtual table generation"
+                   " (use -ftemplate-depth= to increase the maximum)",
+                   max_tinst_depth, decl);
       if (TREE_CODE (decl) == FUNCTION_DECL)
 	/* Pretend that we defined it.  */
 	DECL_INITIAL (decl) = error_mark_node;
@@ -20627,7 +20627,7 @@ get_mostly_instantiated_function_type (tree decl)
 
 /* Return truthvalue if we're processing a template different from
    the last one involved in diagnostics.  */
-int
+bool
 problematic_instantiation_changed (void)
 {
   return current_tinst_level != last_error_tinst_level;
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index c6306b5..0a851f1 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -1639,8 +1639,13 @@ build_x_arrow (location_t loc, tree expr, tsubst_flags_t complain)
 	  if (expr == error_mark_node)
 	    return error_mark_node;
 
+	  /* This provides a better instantiation backtrace in case of
+	     error.  */
 	  if (fn && DECL_USE_TEMPLATE (fn))
-	    push_tinst_level (fn);
+	    push_tinst_level_loc (fn, 
+				  (current_instantiation () != actual_inst)
+				  ? DECL_SOURCE_LOCATION (fn)
+				  : input_location);
 	  fn = NULL;
 
 	  if (vec_member (TREE_TYPE (expr), types_memoized))