173 lines
4.9 KiB
C
173 lines
4.9 KiB
C
/* Representation of thunks inside symbol table.
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Copyright (C) 2003-2022 Free Software Foundation, Inc.
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Contributed by Jan Hubicka
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#ifndef GCC_SYMTAB_THUNKS_H
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#define GCC_SYMTAB_THUNKS_H
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/* This symbol annotation holds information about thunk.
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Thunks are basically wrappers around methods which are introduced in case
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of multiple inheritance in order to adjust the value of the "this" pointer
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or of the returned value.
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In the case of this-adjusting thunks, each back-end can override the
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can_output_mi_thunk/output_mi_thunk target hooks to generate a minimal thunk
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(with a tail call for instance) directly as assembly. For the default hook
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or for the case where the can_output_mi_thunk hooks return false, the thunk
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is gimplified and lowered using the regular machinery. */
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struct GTY(()) thunk_info {
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/* Constructor. */
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thunk_info ()
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: fixed_offset (0),
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virtual_value (0),
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indirect_offset (0),
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alias (NULL),
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this_adjusting (false),
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virtual_offset_p (false)
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{
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}
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/* Copy constructor. */
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thunk_info (const thunk_info &t)
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: fixed_offset (t.fixed_offset),
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virtual_value (t.virtual_value),
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indirect_offset (t.indirect_offset),
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alias (t.alias),
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this_adjusting (t.this_adjusting),
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virtual_offset_p (t.virtual_offset_p)
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{
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}
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/* Compare for equiality. */
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bool
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operator==(const thunk_info &other) const
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{
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return fixed_offset == other.fixed_offset
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&& virtual_value == other.virtual_value
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&& indirect_offset == other.indirect_offset
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&& this_adjusting == other.this_adjusting
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&& virtual_offset_p == other.virtual_offset_p;
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}
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bool
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operator!=(const thunk_info &other) const
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{
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return !(*this == other);
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}
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/* Copy operator. */
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thunk_info &
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operator=(const thunk_info &other)
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{
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fixed_offset = other.fixed_offset;
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virtual_value = other.virtual_value;
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indirect_offset = other.indirect_offset;
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alias = other.alias;
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this_adjusting = other.this_adjusting;
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virtual_offset_p = other.virtual_offset_p;
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return *this;
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}
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/* Offset used to adjust "this". */
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HOST_WIDE_INT fixed_offset;
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/* Offset in the virtual table to get the offset to adjust "this". Valid iff
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VIRTUAL_OFFSET_P is true. */
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HOST_WIDE_INT virtual_value;
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/* Offset from "this" to get the offset to adjust "this". Zero means: this
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offset is to be ignored. */
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HOST_WIDE_INT indirect_offset;
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/* Thunk target, i.e. the method that this thunk wraps. Depending on the
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TARGET_USE_LOCAL_THUNK_ALIAS_P macro, this may have to be a new alias. */
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tree alias;
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/* Nonzero for a "this" adjusting thunk and zero for a result adjusting
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thunk. */
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bool this_adjusting;
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/* If true, this thunk is what we call a virtual thunk. In this case:
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* for this-adjusting thunks, after the FIXED_OFFSET based adjustment is
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done, add to the result the offset found in the vtable at:
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vptr + VIRTUAL_VALUE
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* for result-adjusting thunks, the FIXED_OFFSET adjustment is done after
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the virtual one. */
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bool virtual_offset_p;
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/* Dump thunk_info. */
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void dump (FILE *);
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/* Stream out thunk_info. */
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void stream_out (class lto_simple_output_block *);
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/* Stream in trunk_info. */
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void stream_in (class lto_input_block *);
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hashval_t hash ();
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/* Return thunk_info, if available. */
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static thunk_info *get (cgraph_node *node);
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/* Return thunk_info possibly creating new one. */
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static thunk_info *get_create (cgraph_node *node);
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/* Remove thunk_info. */
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static void remove (cgraph_node *node);
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/* Add unprocessed thunk. */
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void register_early (cgraph_node *node);
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/* Attach recorded thunks to cgraph_nodes. */
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static void process_early_thunks ();
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/* Release all thunk_infos. */
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static void release (void);
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};
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bool expand_thunk (cgraph_node *, bool, bool);
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/* Return thunk_info, if available. */
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inline thunk_info *
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thunk_info::get (cgraph_node *node)
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{
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if (!symtab->m_thunks)
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return NULL;
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return symtab->m_thunks->get (node);
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}
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/* Remove thunk_info association for NODE. */
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inline void
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thunk_info::remove (cgraph_node *node)
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{
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symtab->m_thunks->remove (node);
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}
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/* Free thunk info summaries. */
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inline void
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thunk_info::release ()
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{
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if (symtab->m_thunks)
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ggc_delete (symtab->m_thunks);
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symtab->m_thunks = NULL;
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}
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#endif /* GCC_SYMTAB_THUNKS_H */
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