Adrian, See below for my stab at this issue. Unfortunately it seems to hit a problem in GCC10, as the CI features several failures as follows:
> In file included from ../examples/c++/calc++/driver.hh:24, > from ../examples/c++/calc++/driver.cc:20: > ./examples/c++/calc++/parser.hh: In instantiation of > 'yy::parser::basic_symbol<Base>::basic_symbol(typename Base::kind_type, > int&&, yy::parser::location_type&&) [with Base = yy::parser::by_kind; > typename Base::kind_type = yy::parser::token::token_kind_type; > yy::parser::location_type = yy::location]': > ./examples/c++/calc++/parser.hh:742:68: required from here > ./examples/c++/calc++/parser.hh:583:7: internal compiler error: Segmentation > fault > 583 | basic_symbol (typename Base::kind_type t, int&& v, > location_type&& l) > | ^~~~~~~~~~~~ > Please submit a full bug report, > with preprocessed source if appropriate. > See <file:///usr/share/doc/gcc-10/README.Bugs> for instructions. I'm not super happy to have to play tricks with compiler macros to be able to know if I can trust the compiler :( If you see something wrong in my approach, if you see a nice way to address this portability issue, please state it. The logs of the CI for this commit are here: https://travis-ci.org/github/akimd/bison/builds/755133452 Cheers! commit a7d1aa221efad101d82817345361647fd02a215c Author: Akim Demaille <akim.demai...@gmail.com> Date: Mon Jan 18 08:03:44 2021 +0100 c++: use YY_NOEXCEPT on the constructor when possible Suggested by Adrian <withoutpoi...@gmail.com>. https://lists.gnu.org/r/help-bison/2021-01/msg00008.html * data/skeletons/variant.hh (b4_is_nothrow_move_constructible): New. * data/skeletons/c++.m4: Use it to qualify the basic_symbol ctor. diff --git a/data/skeletons/c++.m4 b/data/skeletons/c++.m4 index cfd4e6ed7..3496450e2 100644 --- a/data/skeletons/c++.m4 +++ b/data/skeletons/c++.m4 @@ -309,7 +309,9 @@ m4_define([b4_symbol_type_define], #if 201103L <= YY_CPLUSPLUS /// Move constructor. - basic_symbol (basic_symbol&& that) + basic_symbol (basic_symbol&& that)]b4_variant_if([ + YY_NOEXCEPT (]b4_type_foreach([b4_is_nothrow_move_constructible], [[ + && ]])[)])[ : Base (std::move (that)) , value (]b4_variant_if([], [std::move (that.value)]))b4_locations_if([ , location (std::move (that.location))])[ diff --git a/data/skeletons/variant.hh b/data/skeletons/variant.hh index ac65c622b..644c5a788 100644 --- a/data/skeletons/variant.hh +++ b/data/skeletons/variant.hh @@ -83,7 +83,11 @@ m4_define([b4_variant_includes], # include <cassert> # define ]b4_assert[ assert #endif -]])]) +]]) +#if 201103L <= YY_CPLUSPLUS +# include <type_traits> +#endif +]) @@ -497,7 +501,8 @@ m4_define([b4_basic_symbol_constructor_define], basic_symbol (]b4_join( [typename Base::kind_type t], b4_symbol_if([$1], [has_type], [b4_symbol([$1], [type])&& v]), - b4_locations_if([location_type&& l]))[) + b4_locations_if([location_type&& l]))[)]b4_symbol_if([$1], [has_type], [ + YY_NOEXCEPT (b4_is_nothrow_move_constructible([$1]))])[ : Base (t)]b4_symbol_if([$1], [has_type], [ , value (std::move (v))])[]b4_locations_if([ , location (std::move (l))])[ @@ -515,6 +520,15 @@ m4_define([b4_basic_symbol_constructor_define], ]]) +# b4_is_nothrow_move_constructible(SYMBOL-NUM) +# -------------------------------------------- +# Participates in the predicate to enable basic_symbol's ctor to be noexpect. +m4_define([b4_is_nothrow_move_constructible], +[b4_symbol_if([$1], [has_type], + [[std::is_nothrow_move_constructible< ]b4_symbol([$1], [type])[ >::value]], + [true])]) + + # b4_token_constructor_define # --------------------------- # Define the overloaded versions of make_symbol for all the value types.
