863c2af6e9
We need to fix some bugs introduced recently, till then, disable steps that try to demote the base type of bitfields and those that move/combine bitfields to save space. We'll revisit those later, bringing them back to the reorg codebase. Acked-by: Andrii Nakryiko <andriin@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Wielaard <mark@klomp.org> Cc: Yonghong Song <yhs@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net># Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
869 lines
25 KiB
C
869 lines
25 KiB
C
/*
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SPDX-License-Identifier: GPL-2.0-only
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Copyright (C) 2006 Mandriva Conectiva S.A.
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Copyright (C) 2006 Arnaldo Carvalho de Melo <acme@mandriva.com>
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Copyright (C) 2007 Red Hat Inc.
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Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
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*/
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#include "list.h"
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#include "dwarves_reorganize.h"
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#include "dwarves.h"
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static void class__recalc_holes(struct class *class)
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{
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class->holes_searched = 0;
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class__find_holes(class);
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}
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void class__subtract_offsets_from(struct class *class,
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struct class_member *from,
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const uint16_t size)
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{
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struct class_member *member =
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list_prepare_entry(from, class__tags(class), tag.node);
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list_for_each_entry_continue(member, class__tags(class), tag.node)
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if (member->tag.tag == DW_TAG_member) {
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member->byte_offset -= size;
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member->bit_offset -= size * 8;
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}
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if (class->padding != 0) {
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struct class_member *last_member =
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type__last_member(&class->type);
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const ssize_t new_padding = (class__size(class) -
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(last_member->byte_offset +
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last_member->byte_size));
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if (new_padding > 0)
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class->padding = new_padding;
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else
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class->padding = 0;
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}
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}
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void class__add_offsets_from(struct class *class, struct class_member *from,
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const uint16_t size)
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{
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struct class_member *member =
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list_prepare_entry(from, class__tags(class), tag.node);
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list_for_each_entry_continue(member, class__tags(class), tag.node)
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if (member->tag.tag == DW_TAG_member) {
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member->byte_offset += size;
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member->bit_offset += size * 8;
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}
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}
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/*
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* XXX: Check this more thoroughly. Right now it is used because I was
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* to lazy to do class__remove_member properly, adjusting alignments and
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* holes as we go removing fields. Ditto for class__add_offsets_from.
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*/
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void class__fixup_alignment(struct class *class, const struct cu *cu)
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{
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struct class_member *pos, *last_member = NULL;
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size_t power2;
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type__for_each_data_member(&class->type, pos) {
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if (last_member == NULL && pos->byte_offset != 0) { /* paranoid! */
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class__subtract_offsets_from(class, pos,
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(pos->byte_offset -
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pos->byte_size));
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pos->byte_offset = 0;
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pos->bit_offset = 0;
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} else if (last_member != NULL &&
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last_member->hole >= cu->addr_size) {
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size_t dec = (last_member->hole / cu->addr_size) *
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cu->addr_size;
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last_member->hole -= dec;
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if (last_member->hole == 0)
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--class->nr_holes;
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pos->byte_offset -= dec;
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pos->bit_offset -= dec * 8;
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class->type.size -= dec;
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class__subtract_offsets_from(class, pos, dec);
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} else for (power2 = cu->addr_size; power2 >= 2; power2 /= 2) {
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const size_t remainder = pos->byte_offset % power2;
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if (pos->byte_size == power2) {
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if (remainder == 0) /* perfectly aligned */
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break;
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if (last_member->hole >= remainder) {
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last_member->hole -= remainder;
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if (last_member->hole == 0)
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--class->nr_holes;
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pos->byte_offset -= remainder;
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pos->bit_offset -= remainder * 8;
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class__subtract_offsets_from(class, pos, remainder);
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} else {
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const size_t inc = power2 - remainder;
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if (last_member->hole == 0)
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++class->nr_holes;
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last_member->hole += inc;
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pos->byte_offset += inc;
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pos->bit_offset += inc * 8;
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class->type.size += inc;
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class__add_offsets_from(class, pos, inc);
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}
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}
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}
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last_member = pos;
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}
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if (last_member != NULL) {
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struct class_member *m =
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type__find_first_biggest_size_base_type_member(&class->type, cu);
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size_t unpadded_size = last_member->byte_offset + last_member->byte_size;
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size_t m_size = m->byte_size, remainder;
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/* google for struct zone_padding in the linux kernel for an example */
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if (m_size == 0)
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return;
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remainder = unpadded_size % m_size;
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if (remainder != 0) {
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class->padding = m_size - remainder;
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class->type.size = unpadded_size + class->padding;
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}
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}
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}
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static struct class_member *
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class__find_next_hole_of_size(struct class *class,
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struct class_member *from, size_t size)
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{
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struct class_member *member =
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list_prepare_entry(from, class__tags(class), tag.node);
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struct class_member *bitfield_head = NULL;
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list_for_each_entry_continue(member, class__tags(class), tag.node) {
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if (member->tag.tag != DW_TAG_member)
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continue;
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if (member->bitfield_size != 0) {
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if (bitfield_head == NULL)
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bitfield_head = member;
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} else
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bitfield_head = NULL;
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if (member->hole != 0) {
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if (member->byte_size != 0 && member->byte_size <= size)
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return bitfield_head ? : member;
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}
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}
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return NULL;
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}
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static struct class_member *
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class__find_last_member_of_size(struct class *class,
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struct class_member *to, size_t size)
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{
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struct class_member *member;
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list_for_each_entry_reverse(member, class__tags(class), tag.node) {
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if (member->tag.tag != DW_TAG_member)
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continue;
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if (member == to)
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break;
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/*
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* Check if this is the first member of a bitfield. It either
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* has another member before it that is not part of the current
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* bitfield or it is the first member of the struct.
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*/
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if (member->bitfield_size != 0 && member->byte_offset != 0) {
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struct class_member *prev =
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list_entry(member->tag.node.prev,
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struct class_member,
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tag.node);
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if (prev->bitfield_size != 0)
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continue;
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}
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if (member->byte_size != 0 && member->byte_size <= size)
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return member;
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}
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return NULL;
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}
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static struct class_member *
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class__find_next_bit_hole_of_size(struct class *class,
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struct class_member *from,
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size_t size)
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{
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struct class_member *member =
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list_prepare_entry(from, class__tags(class), tag.node);
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list_for_each_entry_continue(member, class__tags(class), tag.node) {
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if (member->tag.tag != DW_TAG_member)
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continue;
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if (member->bit_hole != 0 &&
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member->bitfield_size <= size)
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return member;
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}
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#if 0
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/*
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* FIXME: Handle the case where the bit padding is on the same bitfield
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* that we're looking, i.e. we can't combine a bitfield with itclass,
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* perhaps we should tag bitfields with a sequential, clearly marking
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* each of the bitfields in advance, so that all the algoriths that
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* have to deal with bitfields, moving them around, demoting, etc, can
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* be simplified.
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*/
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/*
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* Now look if the last member is a one member bitfield,
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* i.e. if we have bit_padding
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*/
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if (class->bit_padding != 0)
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return type__last_member(&class->type);
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#endif
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return NULL;
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}
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static bool class__move_member(struct class *class, struct class_member *dest,
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struct class_member *from, const struct cu *cu,
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int from_padding, const int verbose, FILE *fp)
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{
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const size_t from_size = from->byte_size;
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const size_t dest_size = dest->byte_size;
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#ifndef BITFIELD_REORG_ALGORITHMS_ENABLED
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/*
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* For now refuse to move a bitfield, we need to first fixup some BRAIN FARTs
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*/
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if (from->bitfield_size != 0)
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return false;
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#endif
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const bool from_was_last = from->tag.node.next == class__tags(class);
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struct class_member *tail_from = from;
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struct class_member *from_prev = list_entry(from->tag.node.prev,
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struct class_member,
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tag.node);
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uint16_t orig_tail_from_hole = tail_from->hole;
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const uint16_t orig_from_offset = from->byte_offset;
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/*
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* Align 'from' after 'dest':
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*/
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const uint16_t offset = dest->hole % (from_size > cu->addr_size ?
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cu->addr_size : from_size);
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/*
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* Set new 'from' offset, after 'dest->byte_offset', aligned
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*/
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const uint16_t new_from_offset = dest->byte_offset + dest_size + offset;
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if (verbose)
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fputs("/* Moving", fp);
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if (from->bitfield_size != 0) {
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struct class_member *pos =
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list_prepare_entry(from, class__tags(class),
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tag.node);
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struct class_member *tmp;
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LIST_HEAD(from_list);
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if (verbose)
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fprintf(fp, " bitfield('%s' ... ",
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class_member__name(from, cu));
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list_for_each_entry_safe_from(pos, tmp, class__tags(class),
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tag.node) {
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if (pos->tag.tag != DW_TAG_member)
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continue;
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/*
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* Have we reached the end of the bitfield?
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*/
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if (pos->byte_offset != orig_from_offset)
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break;
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tail_from = pos;
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orig_tail_from_hole = tail_from->hole;
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pos->byte_offset = new_from_offset;
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pos->bit_offset = new_from_offset * 8 + pos->bitfield_offset;
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list_move_tail(&pos->tag.node, &from_list);
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}
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list_splice(&from_list, &dest->tag.node);
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if (verbose)
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fprintf(fp, "'%s')",
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class_member__name(tail_from, cu));
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} else {
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if (verbose)
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fprintf(fp, " '%s'", class_member__name(from, cu));
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/*
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* Remove 'from' from the list
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*/
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list_del(&from->tag.node);
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/*
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* Add 'from' after 'dest':
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*/
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__list_add(&from->tag.node, &dest->tag.node,
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dest->tag.node.next);
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from->byte_offset = new_from_offset;
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from->bit_offset = new_from_offset * 8 + from->bitfield_offset;
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}
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if (verbose)
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fprintf(fp, " from after '%s' to after '%s' */\n",
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class_member__name(from_prev, cu),
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class_member__name(dest, cu));
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if (from_padding) {
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/*
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* Check if we're eliminating the need for padding:
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*/
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if (orig_from_offset % cu->addr_size == 0) {
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/*
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* Good, no need for padding anymore:
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*/
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class->type.size -= from_size + class->padding;
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} else {
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/*
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* No, so just add from_size to the padding:
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*/
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if (verbose)
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fprintf(fp, "/* adding %zd bytes from %s to "
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"the padding */\n",
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from_size, class_member__name(from, cu));
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}
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} else if (from_was_last) {
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class->type.size -= from_size + class->padding;
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} else {
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/*
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* See if we are adding a new hole that is bigger than
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* sizeof(long), this may have problems with explicit alignment
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* made by the programmer, perhaps we need A switch that allows
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* us to avoid realignment, just using existing holes but
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* keeping the existing alignment, anyway the programmer has to
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* check the resulting rerganization before using it, and for
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* automatic stuff such as the one that will be used for struct
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* "views" in tools such as ctracer we are more interested in
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* packing the subset as tightly as possible.
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*/
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if (orig_tail_from_hole + from_size >= cu->addr_size) {
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class->type.size -= cu->addr_size;
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class__subtract_offsets_from(class, from_prev,
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cu->addr_size);
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}
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}
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class__recalc_holes(class);
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if (verbose > 1) {
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class__fprintf(class, cu, fp);
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fputc('\n', fp);
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}
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return true;
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}
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static void class__move_bit_member(struct class *class, const struct cu *cu,
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struct class_member *dest,
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struct class_member *from,
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const int verbose, FILE *fp)
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{
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struct class_member *from_prev = list_entry(from->tag.node.prev,
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struct class_member,
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tag.node);
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const uint8_t is_last_member = (from->tag.node.next ==
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class__tags(class));
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if (verbose)
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fprintf(fp, "/* Moving '%s:%u' from after '%s' to "
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"after '%s:%u' */\n",
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class_member__name(from, cu), from->bitfield_size,
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class_member__name(from_prev, cu),
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class_member__name(dest, cu), dest->bitfield_size);
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/*
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* Remove 'from' from the list
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*/
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list_del(&from->tag.node);
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/*
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* Add from after dest:
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*/
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__list_add(&from->tag.node,
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&dest->tag.node,
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dest->tag.node.next);
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/* Check if this was the last entry in the bitfield */
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if (from_prev->bitfield_size == 0) {
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size_t from_size = from->byte_size;
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/*
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* Are we shrinking the struct?
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*/
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if (from_size + from->hole >= cu->addr_size) {
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class->type.size -= from_size + from->hole;
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class__subtract_offsets_from(class, from_prev,
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from_size + from->hole);
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}
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}
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/*
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* Tricky, what are the rules for bitfield layouts on this arch?
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* Assume its IA32
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*/
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from->bitfield_offset = dest->bitfield_offset + dest->bitfield_size;
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/*
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* Now both have the same offset:
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*/
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from->byte_offset = dest->byte_offset;
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from->bit_offset = dest->byte_offset * 8 + from->bitfield_offset;
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class__recalc_holes(class);
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if (verbose > 1) {
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class__fprintf(class, cu, fp);
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fputc('\n', fp);
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}
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}
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static void class__demote_bitfield_members(struct class *class,
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struct class_member *from,
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struct class_member *to,
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const struct base_type *old_type,
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const struct base_type *new_type,
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type_id_t new_type_id)
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{
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struct class_member *member =
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list_prepare_entry(from, class__tags(class), tag.node);
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list_for_each_entry_from(member, class__tags(class), tag.node) {
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if (member->tag.tag != DW_TAG_member)
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continue;
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member->byte_size = new_type->bit_size / 8;
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member->tag.type = new_type_id;
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if (member == to)
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break;
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}
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}
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static struct tag *cu__find_base_type_of_size(const struct cu *cu,
|
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const size_t size, type_id_t *id)
|
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{
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const char *type_name, *type_name_alt = NULL;
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switch (size) {
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case sizeof(unsigned char):
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type_name = "unsigned char"; break;
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case sizeof(unsigned short int):
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type_name = "short unsigned int";
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type_name_alt = "unsigned short"; break;
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case sizeof(unsigned int):
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type_name = "unsigned int";
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type_name_alt = "unsigned"; break;
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case sizeof(unsigned long long):
|
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if (cu->addr_size == 8) {
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type_name = "long unsigned int";
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type_name_alt = "unsigned long";
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} else {
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type_name = "long long unsigned int";
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type_name_alt = "unsigned long long";
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}
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break;
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default:
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return NULL;
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}
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|
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struct tag *ret = cu__find_base_type_by_name(cu, type_name, id);
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return ret ?: cu__find_base_type_by_name(cu, type_name_alt, id);
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}
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|
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static int class__demote_bitfields(struct class *class, const struct cu *cu,
|
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const int verbose, FILE *fp)
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{
|
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struct class_member *member;
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struct class_member *bitfield_head = NULL;
|
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const struct tag *old_type_tag, *new_type_tag;
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size_t current_bitfield_size = 0, size, bytes_needed;
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int some_was_demoted = 0;
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|
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type__for_each_data_member(&class->type, member) {
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/*
|
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* Check if we are moving away from a bitfield
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*/
|
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if (member->bitfield_size == 0) {
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current_bitfield_size = 0;
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bitfield_head = NULL;
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} else {
|
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if (bitfield_head == NULL) {
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bitfield_head = member;
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current_bitfield_size = member->bitfield_size;
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} else if (bitfield_head->byte_offset != member->byte_offset) {
|
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/*
|
|
* We moved from one bitfield to another, for
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* now don't handle this case, just move on to
|
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* the next bitfield, we may well move it to
|
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* another place and then the first bitfield will
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* be isolated and will be handled in the next
|
|
* pass.
|
|
*/
|
|
bitfield_head = member;
|
|
current_bitfield_size = member->bitfield_size;
|
|
} else
|
|
current_bitfield_size += member->bitfield_size;
|
|
}
|
|
|
|
/*
|
|
* Have we got to the end of a bitfield with holes?
|
|
*/
|
|
if (member->bit_hole == 0)
|
|
continue;
|
|
|
|
size = member->byte_size;
|
|
bytes_needed = (current_bitfield_size + 7) / 8;
|
|
bytes_needed = roundup_pow_of_two(bytes_needed);
|
|
if (bytes_needed == size)
|
|
continue;
|
|
|
|
type_id_t new_type_id;
|
|
old_type_tag = cu__type(cu, member->tag.type);
|
|
new_type_tag = cu__find_base_type_of_size(cu, bytes_needed,
|
|
&new_type_id);
|
|
|
|
if (new_type_tag == NULL) {
|
|
fprintf(fp, "/* BRAIN FART ALERT! couldn't find a "
|
|
"%zd bytes base type */\n\n", bytes_needed);
|
|
continue;
|
|
}
|
|
if (verbose) {
|
|
char old_bf[64], new_bf[64];
|
|
fprintf(fp, "/* Demoting bitfield ('%s' ... '%s') "
|
|
"from '%s' to '%s' */\n",
|
|
class_member__name(bitfield_head, cu),
|
|
class_member__name(member, cu),
|
|
base_type__name(tag__base_type(old_type_tag),
|
|
cu, old_bf, sizeof(old_bf)),
|
|
base_type__name(tag__base_type(new_type_tag),
|
|
cu, new_bf, sizeof(new_bf)));
|
|
}
|
|
|
|
class__demote_bitfield_members(class,
|
|
bitfield_head, member,
|
|
tag__base_type(old_type_tag),
|
|
tag__base_type(new_type_tag),
|
|
new_type_id);
|
|
class__recalc_holes(class);
|
|
some_was_demoted = 1;
|
|
|
|
if (verbose > 1) {
|
|
class__fprintf(class, cu, fp);
|
|
fputc('\n', fp);
|
|
}
|
|
}
|
|
/*
|
|
* Now look if we have bit padding, i.e. if the the last member
|
|
* is a bitfield and its the sole member in this bitfield, i.e.
|
|
* if it wasn't already demoted as part of a bitfield of more than
|
|
* one member:
|
|
*/
|
|
member = type__last_member(&class->type);
|
|
if (class->bit_padding != 0 && bitfield_head == member) {
|
|
size = member->byte_size;
|
|
bytes_needed = (member->bitfield_size + 7) / 8;
|
|
if (bytes_needed < size) {
|
|
old_type_tag = cu__type(cu, member->tag.type);
|
|
type_id_t new_type_id;
|
|
new_type_tag =
|
|
cu__find_base_type_of_size(cu, bytes_needed,
|
|
&new_type_id);
|
|
|
|
tag__assert_search_result(old_type_tag);
|
|
tag__assert_search_result(new_type_tag);
|
|
|
|
if (verbose) {
|
|
char old_bf[64], new_bf[64];
|
|
fprintf(fp, "/* Demoting bitfield ('%s') "
|
|
"from '%s' to '%s' */\n",
|
|
class_member__name(member, cu),
|
|
base_type__name(tag__base_type(old_type_tag),
|
|
cu, old_bf, sizeof(old_bf)),
|
|
base_type__name(tag__base_type(new_type_tag),
|
|
cu, new_bf, sizeof(new_bf)));
|
|
}
|
|
class__demote_bitfield_members(class,
|
|
member, member,
|
|
tag__base_type(old_type_tag),
|
|
tag__base_type(new_type_tag),
|
|
new_type_id);
|
|
class__recalc_holes(class);
|
|
some_was_demoted = 1;
|
|
|
|
if (verbose > 1) {
|
|
class__fprintf(class, cu, fp);
|
|
fputc('\n', fp);
|
|
}
|
|
}
|
|
}
|
|
|
|
return some_was_demoted;
|
|
}
|
|
|
|
static void class__reorganize_bitfields(struct class *class,
|
|
const struct cu *cu,
|
|
const int verbose, FILE *fp)
|
|
{
|
|
struct class_member *member, *brother;
|
|
restart:
|
|
type__for_each_data_member(&class->type, member) {
|
|
/* See if we have a hole after this member */
|
|
if (member->bit_hole != 0) {
|
|
/*
|
|
* OK, try to find a member that has a bit hole after
|
|
* it and that has a size that fits the current hole:
|
|
*/
|
|
brother =
|
|
class__find_next_bit_hole_of_size(class, member,
|
|
member->bit_hole);
|
|
if (brother != NULL) {
|
|
class__move_bit_member(class, cu,
|
|
member, brother,
|
|
verbose, fp);
|
|
goto restart;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static void class__fixup_bitfield_types(struct class *class,
|
|
struct class_member *from,
|
|
struct class_member *to_before,
|
|
type_id_t type)
|
|
{
|
|
struct class_member *member =
|
|
list_prepare_entry(from, class__tags(class), tag.node);
|
|
|
|
list_for_each_entry_from(member, class__tags(class), tag.node) {
|
|
if (member->tag.tag != DW_TAG_member)
|
|
continue;
|
|
if (member == to_before)
|
|
break;
|
|
member->tag.type = type;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Think about this pahole output a bit:
|
|
*
|
|
* [filo examples]$ pahole swiss_cheese cheese
|
|
* / * <11b> /home/acme/git/pahole/examples/swiss_cheese.c:3 * /
|
|
* struct cheese {
|
|
* <SNIP>
|
|
* int bitfield1:1; / * 64 4 * /
|
|
* int bitfield2:1; / * 64 4 * /
|
|
*
|
|
* / * XXX 14 bits hole, try to pack * /
|
|
* / * Bitfield WARNING: DWARF size=4, real size=2 * /
|
|
*
|
|
* short int d; / * 66 2 * /
|
|
* <SNIP>
|
|
*
|
|
* The compiler (gcc 4.1.1 20070105 (Red Hat 4.1.1-51) in the above example),
|
|
* Decided to combine what was declared as an int (4 bytes) bitfield but doesn't
|
|
* uses even one byte with the next field, that is a short int (2 bytes),
|
|
* without demoting the type of the bitfield to short int (2 bytes), so in terms
|
|
* of alignment the real size is 2, not 4, to make things easier for the rest of
|
|
* the reorganizing routines we just do the demotion ourselves, fixing up the
|
|
* sizes.
|
|
*/
|
|
static void class__fixup_member_types(struct class *class, const struct cu *cu,
|
|
const uint8_t verbose, FILE *fp)
|
|
{
|
|
struct class_member *pos, *bitfield_head = NULL;
|
|
uint8_t fixup_was_done = 0;
|
|
|
|
type__for_each_data_member(&class->type, pos) {
|
|
/*
|
|
* Is this bitfield member?
|
|
*/
|
|
if (pos->bitfield_size != 0) {
|
|
/*
|
|
* The first entry in a bitfield?
|
|
*/
|
|
if (bitfield_head == NULL)
|
|
bitfield_head = pos;
|
|
continue;
|
|
}
|
|
/*
|
|
* OK, not a bitfield member, but have we just passed
|
|
* by a bitfield?
|
|
*/
|
|
if (bitfield_head != NULL) {
|
|
const uint16_t real_size = (pos->byte_offset -
|
|
bitfield_head->byte_offset);
|
|
const size_t size = bitfield_head->byte_size;
|
|
/*
|
|
* Another case:
|
|
struct irq_cfg {
|
|
struct irq_pin_list * irq_2_pin; / * 0 8 * /
|
|
cpumask_var_t domain; / * 8 16 * /
|
|
cpumask_var_t old_domain; / * 24 16 * /
|
|
u8 vector; / * 40 1 * /
|
|
u8 move_in_progress:1; / * 41: 7 1 * /
|
|
u8 remapped:1; / * 41: 6 1 * /
|
|
|
|
/ * XXX 6 bits hole, try to pack * /
|
|
/ * XXX 6 bytes hole, try to pack * /
|
|
|
|
union {
|
|
struct irq_2_iommu irq_2_iommu; / * 16 * /
|
|
struct irq_2_irte irq_2_irte; / * 4 * /
|
|
}; / * 48 16 * /
|
|
/ * --- cacheline 1 boundary (64 bytes) --- * /
|
|
|
|
* So just fix it up if the byte_size of the bitfield is
|
|
* greater than what it really uses.
|
|
*/
|
|
if (real_size < size) {
|
|
type_id_t new_type_id;
|
|
struct tag *new_type_tag =
|
|
cu__find_base_type_of_size(cu,
|
|
real_size,
|
|
&new_type_id);
|
|
if (new_type_tag == NULL) {
|
|
fprintf(stderr, "%s: couldn't find"
|
|
" a base_type of %d bytes!\n",
|
|
__func__, real_size);
|
|
continue;
|
|
}
|
|
class__fixup_bitfield_types(class,
|
|
bitfield_head, pos,
|
|
new_type_id);
|
|
fixup_was_done = 1;
|
|
}
|
|
}
|
|
bitfield_head = NULL;
|
|
}
|
|
if (fixup_was_done) {
|
|
class__recalc_holes(class);
|
|
}
|
|
if (verbose && fixup_was_done) {
|
|
fprintf(fp, "/* bitfield types were fixed */\n");
|
|
if (verbose > 1) {
|
|
class__fprintf(class, cu, fp);
|
|
fputc('\n', fp);
|
|
}
|
|
}
|
|
}
|
|
|
|
void class__reorganize(struct class *class, const struct cu *cu,
|
|
const int verbose, FILE *fp)
|
|
{
|
|
struct class_member *member, *brother, *last_member;
|
|
size_t alignment_size;
|
|
|
|
class__find_holes(class);
|
|
#ifdef BITFIELD_REORG_ALGORITHMS_ENABLED
|
|
class__fixup_member_types(class, cu, verbose, fp);
|
|
while (class__demote_bitfields(class, cu, verbose, fp))
|
|
class__reorganize_bitfields(class, cu, verbose, fp);
|
|
#endif
|
|
/* Now try to combine holes */
|
|
restart:
|
|
alignment_size = 0;
|
|
/*
|
|
* It can be NULL if this class doesn't have any data members,
|
|
* just inheritance entries
|
|
*/
|
|
last_member = type__last_member(&class->type);
|
|
if (last_member == NULL)
|
|
return;
|
|
|
|
type__for_each_data_member(&class->type, member) {
|
|
const size_t aligned_size = member->byte_size + member->hole;
|
|
if (aligned_size <= cu->addr_size &&
|
|
aligned_size > alignment_size)
|
|
alignment_size = aligned_size;
|
|
}
|
|
|
|
if (alignment_size != 0) {
|
|
size_t modulo;
|
|
uint16_t new_padding;
|
|
|
|
if (alignment_size > 1)
|
|
alignment_size = roundup(alignment_size, 2);
|
|
modulo = (last_member->byte_offset +
|
|
last_member->byte_size) % alignment_size;
|
|
if (modulo != 0)
|
|
new_padding = cu->addr_size - modulo;
|
|
else
|
|
new_padding = 0;
|
|
|
|
if (new_padding != class->padding) {
|
|
class->padding = new_padding;
|
|
class->type.size = (last_member->byte_offset +
|
|
last_member->byte_size + new_padding);
|
|
}
|
|
}
|
|
|
|
type__for_each_data_member(&class->type, member) {
|
|
/* See if we have a hole after this member */
|
|
if (member->hole != 0) {
|
|
/*
|
|
* OK, try to find a member that has a hole after it
|
|
* and that has a size that fits the current hole:
|
|
*/
|
|
brother = class__find_next_hole_of_size(class, member,
|
|
member->hole);
|
|
if (brother != NULL) {
|
|
struct class_member *brother_prev =
|
|
list_entry(brother->tag.node.prev,
|
|
struct class_member,
|
|
tag.node);
|
|
/*
|
|
* If it the next member, avoid moving it closer,
|
|
* it could be a explicit alignment rule, like
|
|
* ____cacheline_aligned_in_smp in the Linux
|
|
* kernel.
|
|
*/
|
|
if (brother_prev != member) {
|
|
if (class__move_member(class, member, brother, cu, 0, verbose, fp))
|
|
goto restart;
|
|
}
|
|
}
|
|
/*
|
|
* OK, but is there padding? If so the last member
|
|
* has a hole, if we are not at the last member and
|
|
* it has a size that is smaller than the current hole
|
|
* we can move it after the current member, reducing
|
|
* the padding or eliminating it altogether.
|
|
*/
|
|
if (class->padding > 0 &&
|
|
member != last_member &&
|
|
last_member->byte_size != 0 &&
|
|
last_member->byte_size <= member->hole) {
|
|
if (class__move_member(class, member, last_member, cu, 1, verbose, fp))
|
|
goto restart;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Now try to move members at the tail to after holes */
|
|
if (class->nr_holes == 0)
|
|
return;
|
|
|
|
type__for_each_data_member(&class->type, member) {
|
|
/* See if we have a hole after this member */
|
|
if (member->hole != 0) {
|
|
brother = class__find_last_member_of_size(class, member,
|
|
member->hole);
|
|
if (brother != NULL) {
|
|
struct class_member *brother_prev =
|
|
list_entry(brother->tag.node.prev,
|
|
struct class_member,
|
|
tag.node);
|
|
/*
|
|
* If it the next member, avoid moving it closer,
|
|
* it could be a explicit alignment rule, like
|
|
* ____cacheline_aligned_in_smp in the Linux
|
|
* kernel.
|
|
*/
|
|
if (brother_prev != member) {
|
|
if (class__move_member(class, member, brother, cu, 0, verbose, fp))
|
|
goto restart;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|