Following a suggestion in PR16564, this patch makes excessive template
instantiation depth a fatal error. In fact, this allows simplifying
the code a lot, just by printing first the context (like we do for
every other diagnostic) instead of printing it after (which is not
possible for a fatal error).
This changes the output of quite a few testcases, so before modifying
those I would like to know whether the idea is OK.
Examples of changed output are:
[Before]
g++.dg/cpp0x/decltype26.C:6:15: error: template instantiation depth
exceeds maximum of 900 (use -ftemplate-depth= to increase the maximum)
substituting 'template<class T> decltype (f(T())) f(T) [with T =
<missing>]'
g++.dg/cpp0x/decltype26.C:6:15: recursively required by substitution
of 'template<class T> decltype (f(T())) f(T) [with T = A]'
g++.dg/cpp0x/decltype26.C:6:15: required by substitution of
'template<class T> decltype (f(T())) f(T) [with T = A]'
g++.dg/cpp0x/decltype26.C:13:8: required from here
g++.dg/cpp0x/decltype26.C: In function 'int main()':
g++.dg/cpp0x/decltype26.C:13:8: error: no matching function for call to 'f(A)'
g++.dg/cpp0x/decltype26.C:6:18: note: candidate: template<class T>
decltype (f(T())) f(T)
g++.dg/cpp0x/decltype26.C:6:18: note: substitution of deduced
template arguments resulted in errors seen above
[After]
g++.dg/cpp0x/decltype26.C: In substitution of 'template<class T>
decltype (f(T())) f(T) [with T = A]':
g++.dg/cpp0x/decltype26.C:6:15: recursively required by substitution
of 'template<class T> decltype (f(T())) f(T) [with T = A]'
g++.dg/cpp0x/decltype26.C:6:15: required by substitution of
'template<class T> decltype (f(T())) f(T) [with T = A]'
g++.dg/cpp0x/decltype26.C:13:8: required from here
g++.dg/cpp0x/decltype26.C:6:15: fatal error: template instantiation
depth exceeds maximum of 900 (use -ftemplate-depth= to increase the
maximum)
One interesting case is for operator->(). Here we have to adjust
the location of the template instantiations so we can point the
user to the point of recursion:
[Before]
g++.dg/template/arrow1.C:12:11: error: template instantiation depth
exceeds maximum of 900 (use -ftemplate-depth= to increase the maximum)
instantiating 'a<(n + 1)> a<n>::operator->() [with int n = 900]'
g++.dg/template/arrow1.C:12:11: recursively required from 'a<(n +
1)> a<n>::operator->() [with int n = 0]'
g++.dg/template/arrow1.C:12:11: required from here
g++.dg/template/arrow1.C:12:11: error: template instantiation depth
exceeds maximum of 900 (use -ftemplate-depth= to increase the maximum)
instantiating 'struct a<901>'
g++.dg/template/arrow1.C:12:11: recursively required from 'a<(n +
1)> a<n>::operator->() [with int n = 0]'
g++.dg/template/arrow1.C:12:11: required from here
g++.dg/template/arrow1.C:12:11: error: invalid use of incomplete type
'struct a<901>'
g++.dg/template/arrow1.C:5:8: note: declaration of 'struct a<901>'
[After]
g++.dg/template/arrow1.C: In instantiation of 'a<(n + 1)>
a<n>::operator->() [with int n = 899]':
g++.dg/template/arrow1.C:7:2: recursively required from 'a<(n + 1)>
a<n>::operator->() [with int n = 1]'
g++.dg/template/arrow1.C:7:2: required from 'a<(n + 1)>
a<n>::operator->() [with int n = 0]'
g++.dg/template/arrow1.C:12:11: required from here
g++.dg/template/arrow1.C:12:11: fatal error: template instantiation
depth exceeds maximum of 900 (use -ftemplate-depth= to increase the
maximum)
The rest of testcases follow the pattern:
[Before]
g++.dg/template/pr23510.C:9:1: error: expected ';' after struct definition
g++.dg/template/pr23510.C:6:27: error: template instantiation depth
exceeds maximum of 15 (use -ftemplate-depth= to increase the maximum)
instantiating 'struct Factorial<5u>'
g++.dg/template/pr23510.C:6:27: recursively required from 'struct
Factorial<19u>'
g++.dg/template/pr23510.C:6:27: required from 'struct Factorial<20u>'
g++.dg/template/pr23510.C:21:20: required from here
[After]
g++.dg/template/pr23510.C:9:1: error: expected ';' after struct definition
g++.dg/template/pr23510.C: In instantiation of 'struct Factorial<6u>':
g++.dg/template/pr23510.C:6:27: recursively required from 'struct
Factorial<19u>'
g++.dg/template/pr23510.C:6:27: required from 'struct Factorial<20u>'
g++.dg/template/pr23510.C:21:20: required from here
g++.dg/template/pr23510.C:6:27: fatal error: template instantiation
depth exceeds maximum of 15 (use -ftemplate-depth= to increase the
maximum)
Apart from these changes, the patch bootstraps and passes the
regression suite on x86_64-linux.
OK with the updated testcases?
gcc/cp/ChangeLog:
2014-08-17 Manuel López-Ibáñez <m...@gcc.gnu.org>
* 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.
gcc/testsuite/ChangeLog:
2014-08-17 Manuel López-Ibáñez <m...@gcc.gnu.org>
* 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.
Index: gcc/testsuite/lib/gcc.exp
===================================================================
--- gcc/testsuite/lib/gcc.exp (revision 214029)
+++ gcc/testsuite/lib/gcc.exp (working copy)
@@ -109,11 +109,11 @@ proc gcc_init { args } {
if ![info exists tmpdir] then {
set tmpdir /tmp
}
set gcc_warning_prefix "warning:"
- set gcc_error_prefix "error:"
+ set gcc_error_prefix "(fatal )?error:"
gcc_maybe_build_wrapper "${tmpdir}/gcc-testglue.o"
}
#
Index: gcc/testsuite/lib/g++.exp
===================================================================
--- gcc/testsuite/lib/g++.exp (revision 214029)
+++ gcc/testsuite/lib/g++.exp (working copy)
@@ -265,11 +265,11 @@ proc g++_init { args } {
# Make sure that lines are not wrapped. That can confuse the
# error-message parsing machinery.
lappend ALWAYS_CXXFLAGS "additional_flags=-fmessage-length=0"
set gcc_warning_prefix "warning:"
- set gcc_error_prefix "error:"
+ set gcc_error_prefix "(fatal )?error:"
if { [istarget *-*-darwin*] } {
lappend ALWAYS_CXXFLAGS "ldflags=-multiply_defined suppress"
}
Index: gcc/testsuite/lib/obj-c++.exp
===================================================================
--- gcc/testsuite/lib/obj-c++.exp (revision 214029)
+++ gcc/testsuite/lib/obj-c++.exp (working copy)
@@ -273,11 +273,11 @@ proc obj-c++_init { args } {
# Make sure that lines are not wrapped. That can confuse the
# error-message parsing machinery.
lappend ALWAYS_OBJCXXFLAGS "additional_flags=-fmessage-length=0"
set gcc_warning_prefix "warning:"
- set gcc_error_prefix "error:"
+ set gcc_error_prefix "(fatal )?error:"
if { [istarget *-*-darwin*] } {
lappend ALWAYS_OBJCXXFLAGS "ldflags=-multiply_defined suppress"
}
Index: gcc/testsuite/lib/objc.exp
===================================================================
--- gcc/testsuite/lib/objc.exp (revision 214029)
+++ gcc/testsuite/lib/objc.exp (working copy)
@@ -122,11 +122,11 @@ proc objc_init { args } {
if ![info exists tmpdir] then {
set tmpdir /tmp
}
set gcc_warning_prefix "warning:"
- set gcc_error_prefix "error:"
+ set gcc_error_prefix "(fatal )?error:"
objc_maybe_build_wrapper "${tmpdir}/objc-testglue.o"
set objc_libgcc_s_path [gcc-set-multilib-library-path $OBJC_UNDER_TEST]
}
Index: gcc/testsuite/g++.dg/template/pr16564.C
===================================================================
--- gcc/testsuite/g++.dg/template/pr16564.C (revision 0)
+++ gcc/testsuite/g++.dg/template/pr16564.C (revision 0)
@@ -0,0 +1,8 @@
+// { dg-do compile }
+template<typename> struct A
+{
+ A<A> a; /* { dg-error "template instantiation depth" } */
+ A() {}
+};
+
+A<int> a;
Index: gcc/cp/error.c
===================================================================
--- gcc/cp/error.c (revision 214029)
+++ gcc/cp/error.c (working copy)
@@ -3351,20 +3351,10 @@ maybe_print_instantiation_context (diagn
return;
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. */
void
maybe_print_constexpr_context (diagnostic_context *context)
Index: gcc/cp/typeck2.c
===================================================================
--- gcc/cp/typeck2.c (revision 214029)
+++ gcc/cp/typeck2.c (working copy)
@@ -1635,12 +1635,17 @@ build_x_arrow (location_t loc, tree expr
&fn, 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))
{
if (complain & tf_error)
Index: gcc/cp/pt.c
===================================================================
--- gcc/cp/pt.c (revision 214029)
+++ gcc/cp/pt.c (working copy)
@@ -8334,51 +8334,51 @@ int depth_reached;
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;
current_tinst_level = new_level;
++tinst_depth;
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
context. */
@@ -20230,14 +20230,14 @@ instantiate_pending_templates (int retri
to avoid infinite loop. */
if (pending_templates && retries >= max_tinst_depth)
{
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;
return;
}
@@ -20566,11 +20566,11 @@ get_mostly_instantiated_function_type (t
return fn_type;
}
/* 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;
}
Index: gcc/cp/cp-tree.h
===================================================================
--- gcc/cp/cp-tree.h (revision 214029)
+++ gcc/cp/cp-tree.h (working copy)
@@ -5410,11 +5410,10 @@ extern const char *decl_as_dwarf_string
extern const char *expr_as_string (tree, int);
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);
extern location_t location_of (tree);
extern void qualified_name_lookup_error (tree, tree, tree,
@@ -5625,11 +5624,11 @@ extern tree tsubst_default_argument (tr
extern tree tsubst (tree, tree, tsubst_flags_t, tree);
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);
extern int processing_template_parmlist;
extern bool dependent_type_p (tree);
@@ -5653,11 +5652,12 @@ extern bool reregister_specialization (
extern tree fold_non_dependent_expr (tree);
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);
extern void print_template_statistics (void);
bool template_template_parameter_p (const_tree);
