URL
https://opencores.org/ocsvn/openrisc/openrisc/trunk
Subversion Repositories openrisc
[/] [openrisc/] [tags/] [gnu-src/] [gcc-4.5.1/] [gcc-4.5.1-or32-1.0rc3/] [libstdc++-v3/] [libsupc++/] [vmi_class_type_info.cc] - Rev 799
Go to most recent revision | Compare with Previous | Blame | View Log
// Copyright (C) 1994, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2007, 2009 // Free Software Foundation // // This file is part of GCC. // // GCC is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation; either version 3, or (at your option) // any later version. // GCC is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. #include "tinfo.h" namespace __cxxabiv1 { __vmi_class_type_info:: ~__vmi_class_type_info () {} __class_type_info::__sub_kind __vmi_class_type_info:: __do_find_public_src (ptrdiff_t src2dst, const void *obj_ptr, const __class_type_info *src_type, const void *src_ptr) const { if (obj_ptr == src_ptr && *this == *src_type) return __contained_public; for (std::size_t i = __base_count; i--;) { if (!__base_info[i].__is_public_p ()) continue; // Not public, can't be here. const void *base = obj_ptr; ptrdiff_t offset = __base_info[i].__offset (); bool is_virtual = __base_info[i].__is_virtual_p (); if (is_virtual) { if (src2dst == -3) continue; // Not a virtual base, so can't be here. } base = convert_to_base (base, is_virtual, offset); __sub_kind base_kind = __base_info[i].__base_type->__do_find_public_src (src2dst, base, src_type, src_ptr); if (contained_p (base_kind)) { if (is_virtual) base_kind = __sub_kind (base_kind | __contained_virtual_mask); return base_kind; } } return __not_contained; } // This is a big hairy function. Although the run-time behaviour of // dynamic_cast is simple to describe, it gives rise to some non-obvious // behaviour. We also desire to determine as early as possible any definite // answer we can get. Because it is unknown what the run-time ratio of // succeeding to failing dynamic casts is, we do not know in which direction // to bias any optimizations. To that end we make no particular effort towards // early fail answers or early success answers. Instead we try to minimize // work by filling in things lazily (when we know we need the information), // and opportunisticly take early success or failure results. bool __vmi_class_type_info:: __do_dyncast (ptrdiff_t src2dst, __sub_kind access_path, const __class_type_info *dst_type, const void *obj_ptr, const __class_type_info *src_type, const void *src_ptr, __dyncast_result &__restrict result) const { if (result.whole_details & __flags_unknown_mask) result.whole_details = __flags; if (obj_ptr == src_ptr && *this == *src_type) { // The src object we started from. Indicate how we are accessible from // the most derived object. result.whole2src = access_path; return false; } if (*this == *dst_type) { result.dst_ptr = obj_ptr; result.whole2dst = access_path; if (src2dst >= 0) result.dst2src = adjust_pointer <void> (obj_ptr, src2dst) == src_ptr ? __contained_public : __not_contained; else if (src2dst == -2) result.dst2src = __not_contained; return false; } // If src_type is a unique non-virtual base of dst_type, we have a good // guess at the address we want, so in the first pass try skipping any // bases which don't contain that address. const void *dst_cand = NULL; if (src2dst >= 0) dst_cand = adjust_pointer<void>(src_ptr, -src2dst); bool first_pass = true; bool skipped = false; bool result_ambig = false; again: for (std::size_t i = __base_count; i--;) { __dyncast_result result2 (result.whole_details); void const *base = obj_ptr; __sub_kind base_access = access_path; ptrdiff_t offset = __base_info[i].__offset (); bool is_virtual = __base_info[i].__is_virtual_p (); if (is_virtual) base_access = __sub_kind (base_access | __contained_virtual_mask); base = convert_to_base (base, is_virtual, offset); if (dst_cand) { bool skip_on_first_pass = base > dst_cand; if (skip_on_first_pass == first_pass) { // We aren't interested in this base on this pass: either // we're on the first pass and this base doesn't contain the // likely address, or we're on the second pass and we checked // this base on the first pass. skipped = true; continue; } } if (!__base_info[i].__is_public_p ()) { if (src2dst == -2 && !(result.whole_details & (__non_diamond_repeat_mask | __diamond_shaped_mask))) // The hierarchy has no duplicate bases (which might ambiguate // things) and where we started is not a public base of what we // want (so it cannot be a downcast). There is nothing of interest // hiding in a non-public base. continue; base_access = __sub_kind (base_access & ~__contained_public_mask); } bool result2_ambig = __base_info[i].__base_type->__do_dyncast (src2dst, base_access, dst_type, base, src_type, src_ptr, result2); result.whole2src = __sub_kind (result.whole2src | result2.whole2src); if (result2.dst2src == __contained_public || result2.dst2src == __contained_ambig) { result.dst_ptr = result2.dst_ptr; result.whole2dst = result2.whole2dst; result.dst2src = result2.dst2src; // Found a downcast which can't be bettered or an ambiguous downcast // which can't be disambiguated return result2_ambig; } if (!result_ambig && !result.dst_ptr) { // Not found anything yet. result.dst_ptr = result2.dst_ptr; result.whole2dst = result2.whole2dst; result_ambig = result2_ambig; if (result.dst_ptr && result.whole2src != __unknown && !(__flags & __non_diamond_repeat_mask)) // Found dst and src and we don't have repeated bases. return result_ambig; } else if (result.dst_ptr && result.dst_ptr == result2.dst_ptr) { // Found at same address, must be via virtual. Pick the most // accessible path. result.whole2dst = __sub_kind (result.whole2dst | result2.whole2dst); } else if ((result.dst_ptr != 0 && result2.dst_ptr != 0) || (result.dst_ptr != 0 && result2_ambig) || (result2.dst_ptr != 0 && result_ambig)) { // Found two different DST_TYPE bases, or a valid one and a set of // ambiguous ones, must disambiguate. See whether SRC_PTR is // contained publicly within one of the non-ambiguous choices. If it // is in only one, then that's the choice. If it is in both, then // we're ambiguous and fail. If it is in neither, we're ambiguous, // but don't yet fail as we might later find a third base which does // contain SRC_PTR. __sub_kind new_sub_kind = result2.dst2src; __sub_kind old_sub_kind = result.dst2src; if (contained_p (result.whole2src) && (!virtual_p (result.whole2src) || !(result.whole_details & __diamond_shaped_mask))) { // We already found SRC_PTR as a base of most derived, and // either it was non-virtual, or the whole hierarchy is // not-diamond shaped. Therefore if it is in either choice, it // can only be in one of them, and we will already know. if (old_sub_kind == __unknown) old_sub_kind = __not_contained; if (new_sub_kind == __unknown) new_sub_kind = __not_contained; } else { if (old_sub_kind >= __not_contained) ;// already calculated else if (contained_p (new_sub_kind) && (!virtual_p (new_sub_kind) || !(__flags & __diamond_shaped_mask))) // Already found inside the other choice, and it was // non-virtual or we are not diamond shaped. old_sub_kind = __not_contained; else old_sub_kind = dst_type->__find_public_src (src2dst, result.dst_ptr, src_type, src_ptr); if (new_sub_kind >= __not_contained) ;// already calculated else if (contained_p (old_sub_kind) && (!virtual_p (old_sub_kind) || !(__flags & __diamond_shaped_mask))) // Already found inside the other choice, and it was // non-virtual or we are not diamond shaped. new_sub_kind = __not_contained; else new_sub_kind = dst_type->__find_public_src (src2dst, result2.dst_ptr, src_type, src_ptr); } // Neither sub_kind can be contained_ambig -- we bail out early // when we find those. if (contained_p (__sub_kind (new_sub_kind ^ old_sub_kind))) { // Only on one choice, not ambiguous. if (contained_p (new_sub_kind)) { // Only in new. result.dst_ptr = result2.dst_ptr; result.whole2dst = result2.whole2dst; result_ambig = false; old_sub_kind = new_sub_kind; } result.dst2src = old_sub_kind; if (public_p (result.dst2src)) return false; // Can't be an ambiguating downcast for later discovery. if (!virtual_p (result.dst2src)) return false; // Found non-virtually can't be bettered } else if (contained_p (__sub_kind (new_sub_kind & old_sub_kind))) { // In both. result.dst_ptr = NULL; result.dst2src = __contained_ambig; return true; // Fail. } else { // In neither publicly, ambiguous for the moment, but keep // looking. It is possible that it was private in one or // both and therefore we should fail, but that's just tough. result.dst_ptr = NULL; result.dst2src = __not_contained; result_ambig = true; } } if (result.whole2src == __contained_private) // We found SRC_PTR as a private non-virtual base, therefore all // cross casts will fail. We have already found a down cast, if // there is one. return result_ambig; } if (skipped && first_pass) { // We didn't find dst where we expected it, so let's go back and try // the bases we skipped (if any). first_pass = false; goto again; } return result_ambig; } bool __vmi_class_type_info:: __do_upcast (const __class_type_info *dst, const void *obj_ptr, __upcast_result &__restrict result) const { if (__class_type_info::__do_upcast (dst, obj_ptr, result)) return true; int src_details = result.src_details; if (src_details & __flags_unknown_mask) src_details = __flags; for (std::size_t i = __base_count; i--;) { __upcast_result result2 (src_details); const void *base = obj_ptr; ptrdiff_t offset = __base_info[i].__offset (); bool is_virtual = __base_info[i].__is_virtual_p (); bool is_public = __base_info[i].__is_public_p (); if (!is_public && !(src_details & __non_diamond_repeat_mask)) // original cannot have an ambiguous base, so skip private bases continue; if (base) base = convert_to_base (base, is_virtual, offset); if (__base_info[i].__base_type->__do_upcast (dst, base, result2)) { if (result2.base_type == nonvirtual_base_type && is_virtual) result2.base_type = __base_info[i].__base_type; if (contained_p (result2.part2dst) && !is_public) result2.part2dst = __sub_kind (result2.part2dst & ~__contained_public_mask); if (!result.base_type) { result = result2; if (!contained_p (result.part2dst)) return true; // found ambiguously if (result.part2dst & __contained_public_mask) { if (!(__flags & __non_diamond_repeat_mask)) return true; // cannot have an ambiguous other base } else { if (!virtual_p (result.part2dst)) return true; // cannot have another path if (!(__flags & __diamond_shaped_mask)) return true; // cannot have a more accessible path } } else if (result.dst_ptr != result2.dst_ptr) { // Found an ambiguity. result.dst_ptr = NULL; result.part2dst = __contained_ambig; return true; } else if (result.dst_ptr) { // Ok, found real object via a virtual path. result.part2dst = __sub_kind (result.part2dst | result2.part2dst); } else { // Dealing with a null pointer, need to check vbase // containing each of the two choices. if (result2.base_type == nonvirtual_base_type || result.base_type == nonvirtual_base_type || !(*result2.base_type == *result.base_type)) { // Already ambiguous, not virtual or via different virtuals. // Cannot match. result.part2dst = __contained_ambig; return true; } result.part2dst = __sub_kind (result.part2dst | result2.part2dst); } } } return result.part2dst != __unknown; } }
Go to most recent revision | Compare with Previous | Blame | View Log