mirror of
https://git.code.sf.net/p/quake/quakeforge
synced 2024-11-11 07:42:18 +00:00
b81d58c795
This reverts commit a2f203c840.
There is indeed a world of difference between "any" and "only", and it
helps if I read the rest of the docs AND the code :P.
311 lines
11 KiB
C
311 lines
11 KiB
C
/*
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def.h
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def management and symbol tables
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Copyright (C) 2002 Bill Currie <bill@taniwha.org>
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Author: Bill Currie <bill@taniwha.org>
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Date: 2002/06/04
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License 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 this program; if not, write to:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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*/
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#ifndef __def_h
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#define __def_h
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#include "QF/pr_comp.h"
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#include "QF/pr_debug.h"
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/** \defgroup qfcc_def Def handling
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\ingroup qfcc
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*/
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///@{
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struct symbol_s;
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struct expr_s;
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/** Represent a memory location that holds a QuakeC/Ruamoko object.
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The object represented by the def may be of any type (either internally
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defined by qfcc (float, int, vector, etc) or user defined (structs, arrays
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etc)).
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Unless the def is external (ie, declared to be in another compilation
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unit), defs are always attached to a defspace. Storage for the def's
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object is allocated from that space.
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*/
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typedef struct def_s {
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struct def_s *next; ///< general purpose linking
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struct def_s *temp_next; ///< linked list of "free" temp defs
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struct type_s *type; ///< QC type of this def
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const char *name; ///< the def's name
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struct defspace_s *space; ///< defspace to which this def belongs
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int offset; ///< address of this def in its defspace
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/** \name Def aliasing.
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Aliasing a def provides a different view of the def providing access
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via a different type, or access to members of structs, unions and
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arrays.
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Alias defs are very simple: they store only the type and relative
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offset off the def they alias. All other information is held in the
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def they alias, including relocation records. However, they do keep
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track of the source file and line that first created the alias.
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The relations between a def and any of its aliases are maintained by
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a linked list headed by def_t::alias_defs and connected by
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def_t::next. def_t::alias is used to find the main def via one if its
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aliases. The order of the aliases in the list is arbitrary: it is the
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reverse of the order in which they were created.
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\dotfile vector-alias.dot "Accessing a vector via its components."
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*/
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//@{
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struct def_s *alias_defs; ///< defs that alias this def
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struct def_s *alias; ///< real def which this def aliases
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//@}
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struct reloc_s *relocs; ///< for relocations
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struct expr_s *initializer;///< initialer expression
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struct daglabel_s *daglabel;///< daglabel for this def
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struct flowvar_s *flowvar; ///< flowvar for this def
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unsigned offset_reloc:1; ///< use *_def_ofs relocs
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unsigned initialized:1; ///< the def has been initialized
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unsigned constant:1; ///< stores constant value
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unsigned global:1; ///< globally declared def
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unsigned external:1; ///< externally declared def
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unsigned local:1; ///< function local def
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unsigned param:1; ///< function param def
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unsigned system:1; ///< system def
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unsigned nosave:1; ///< don't set DEF_SAVEGLOBAL
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string_t file; ///< declaring/defining source file
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int line; ///< declaring/defining source line
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int qfo_def; ///< index to def in qfo defs
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void *return_addr; ///< who allocated this
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void *free_addr; ///< who freed this
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} def_t;
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/** Specify the storage class of a def.
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*/
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typedef enum storage_class_e {
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sc_global, ///< def is globally visibil across units
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sc_system, ///< def may be redefined once
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sc_extern, ///< def is externally allocated
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sc_static, ///< def is private to the current unit
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sc_param, ///< def is an incoming function parameter
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sc_local ///< def is local to the current function
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} storage_class_t;
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/** Create a new def.
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Defs may be unnamed.
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Untyped defs (used by type encodings) never allocate space for the def.
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If \a storage is not sc_extern and \a type is not null, space of the
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size specified by \a type will be allocated to the def from the defspace
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specified by \a space.
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\param name The name for the def. May be null for unnamed defs.
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\param type The type for the def. May be null for untyped defs.
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\param space The defspace to which the def belongs. Must not be null
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for if \a storage is not sc_extern.
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\param storage The storage class for the def.
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\return The new def.
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*/
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def_t *new_def (const char *name, struct type_s *type,
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struct defspace_s *space, storage_class_t storage);
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/** Create a def that aliases another def.
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Aliasing a def to the same type is useless, but not checked. Aliasing a
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def to a type larger than the def's type will generate an internal error.
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If the offset is negative, or the offset plus the size of the aliasing type
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is greater than the size of the def's type, then an internal error will
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be generated.
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The alias def keeps track of its base def and is attached to the base def
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so any aliases of that def can be found.
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For any combination of type and offset, there will be only one alias def
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created.
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\param def The def to be aliased.
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\param type The type of the alias.
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\param offset Offset of the alias relative to the def.
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\return The def aliasing \a def.
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\todo Make aliasing to the same type a no-op?
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*/
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def_t *alias_def (def_t *def, struct type_s *type, int offset);
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/** Free a def.
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If the def has space allocated to it, the space will be freed.
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\param def The def to be freed.
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*/
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void free_def (def_t *def);
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/** \name Temporary defs
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Temporary defs are used for recycling memory for tempary variables. They
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always have names in the form of <code>.tmpN</code> where N is a
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non-negative integer. The type of the temporary def can change throughout
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its life, but the size will never change.
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Temporary defs are bound to the current function (::current_func must
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be valid). They are always allocated from the funciont's local defspace.
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*/
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///@{
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/** Get a temporary def.
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If the current function has a free temp def of the same size as \a size,
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then that def will be recycled, otherwise a new temp will be created. When
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a new temp is created, its name is set to <code>.tmpN</code> where \c N
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comes from function_t::temp_num, which is then incremented.
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\note ::current_func must be valid.
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\param type The type of the temporary variable.
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\return The def for the temparary variable.
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\bug size of type must be 1 to 4.
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\todo support arbitrary sizes
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*/
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def_t *temp_def (struct type_s *type);
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/** Free a tempary def so it may be recycled.
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The temp is put into a list of free temp defs maintained by ::current_func.
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\note ::current_func must be valid.
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\param temp The temp def to be recycled.
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*/
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void free_temp_def (def_t *temp);
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///@}
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/** Initialize a vm def from a qfcc def.
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\param def The qfcc def to copy.
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\param ddef The vm def to be initialized.
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\param aux Copy the field object's type rather than the def's.
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\bug The def is not verified to be a field def when \a aux is true.
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*/
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void def_to_ddef (def_t *def, ddef_t *ddef, int aux);
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/** Initialize a def referenced by the given symbol.
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The symbol is checked for redefinition. A symbol is considered to be
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redefined if the previous definition is in the same symbol table and
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of a different type or already initialized.
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If \a type is null, then the def will be given the default type (as
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specified by ::type_default).
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If an initializer expressions is given (\a init is not null), then it
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must be a constant expression (eg, 2 + 3) for non-local defs. Aggregate
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types (structs, arrays (unions?)) use block expressions where each
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expression in the block initializes one element of the aggregate. Nested
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aggregates simply use nested block expressions. As for simple types, each
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expression in a block expression must also be constant for non-local defs.
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For \a space and \a storage, see new_def().
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\param sym The symbol for which to create and initialize a def.
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\param init If not null, the expressions to use to initialize the def.
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\param space The space from which to allocate space for the def.
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\param storage The storage class of the def.
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*/
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void initialize_def (struct symbol_s *sym,
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struct expr_s *init, struct defspace_s *space,
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storage_class_t storage);
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/** Determine if two defs overlap.
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\param d1 The first def to check. May be an alias def.
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\param d2 The second def to check. May be an alias def.
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\return 1 if the defs overlap, 2 if \a d1 fully overlaps \a d2,
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otherwise 0.
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*/
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int def_overlap (def_t *d1, def_t *d2) __attribute__((pure));
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/** Convenience function for obtaining a def's actual offset.
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Takes care of an alias def's relative offset.
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\param def The def of which to obtain the offset. May be an alias def.
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\return The actual offset of the def in the def's defspace.
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*/
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int def_offset (def_t *def) __attribute__((pure));
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/** Convenience function for obtaining a def's size.
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Whether the def is an alias or not is irrelevant.
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\param def The def of which to obtain the size.
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\return The size of the def.
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*/
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int def_size (def_t *def) __attribute__((pure));
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/** Visit all defs that alias the given def, including itself.
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First, the given def is visited, and then every candidate def connected
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to the given def via the aliasing links will be visited. Candidate defs
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are those that overlap the given def when \a overlap is true, otherwise
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every connected def is a candidate. \a overlap has no meaning if the
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given def is not an alias def as all alias defs connected to the given
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def are guaranteed to overlap with the given def. Any def will be visited
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at most once.
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The \a visit function may return non-zero to terminate the loop early.
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Any data needed by \a visit should be made available via \a data, which
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will be passed on to \a visit via the second parameter. The first
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parameter of \a visit is the def currently being visted.
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This function is useful also for defs that are not alias defs and do not
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have any aliases: \a visit will be called for the def and then the
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function will return.
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\param def The def representing the alias cluster to visit.
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\param overlap If non-zero, then only defs that overlap \a def will
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be visited. If 2, then the given def must fully overlap
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the visited def.
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\param visit The function to call when visiting a def. The first
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parameter is the def being visited, and the second
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parameter is \a data passed on. If non-zero is returned,
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the pass through the alias cluster will terminate.
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\param data Pointer to the data needed by \a visit.
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\return The value returned by \a visit returned non-zero,
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otherwise 0.
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*/
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int def_visit_all (def_t *def, int overlap,
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int (*visit) (def_t *, void *), void *data);
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///@}
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#endif//__def_h
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