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95 lines
4.2 KiB
C
95 lines
4.2 KiB
C
/* addrmap.h --- interface to address map data structure.
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Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(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. See the
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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, see <http://www.gnu.org/licenses/>. */
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#ifndef ADDRMAP_H
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#define ADDRMAP_H
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/* An address map is essentially a table mapping CORE_ADDRs onto GDB
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data structures, like blocks, symtabs, partial symtabs, and so on.
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An address map uses memory proportional to the number of
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transitions in the map, where a CORE_ADDR N is mapped to one
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object, and N+1 is mapped to a different object.
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Address maps come in two flavors: fixed, and mutable. Mutable
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address maps consume more memory, but can be changed and extended.
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A fixed address map, once constructed (from a mutable address map),
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can't be edited. Both kinds of map are allocated in obstacks. */
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/* The opaque type representing address maps. */
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struct addrmap;
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/* Create a mutable address map which maps every address to NULL.
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Allocate entries in OBSTACK. */
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struct addrmap *addrmap_create_mutable (struct obstack *obstack);
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/* In the mutable address map MAP, associate the addresses from START
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to END_INCLUSIVE that are currently associated with NULL with OBJ
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instead. Addresses mapped to an object other than NULL are left
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unchanged.
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As the name suggests, END_INCLUSIVE is also mapped to OBJ. This
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convention is unusual, but it allows callers to accurately specify
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ranges that abut the top of the address space, and ranges that
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cover the entire address space.
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This operation seems a bit complicated for a primitive: if it's
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needed, why not just have a simpler primitive operation that sets a
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range to a value, wiping out whatever was there before, and then
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let the caller construct more complicated operations from that,
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along with some others for traversal?
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It turns out this is the mutation operation we want to use all the
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time, at least for now. Our immediate use for address maps is to
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represent lexical blocks whose address ranges are not contiguous.
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We walk the tree of lexical blocks present in the debug info, and
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only create 'struct block' objects after we've traversed all a
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block's children. If a lexical block declares no local variables
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(and isn't the lexical block for a function's body), we omit it
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from GDB's data structures entirely.
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However, this means that we don't decide to create a block (and
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thus record it in the address map) until after we've traversed its
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children. If we do decide to create the block, we do so at a time
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when all its children have already been recorded in the map. So
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this operation --- change only those addresses left unset --- is
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actually the operation we want to use every time.
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It seems simpler to let the code which operates on the
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representation directly deal with the hair of implementing these
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semantics than to provide an interface which allows it to be
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implemented efficiently, but doesn't reveal too much of the
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representation. */
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void addrmap_set_empty (struct addrmap *map,
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CORE_ADDR start, CORE_ADDR end_inclusive,
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void *obj);
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/* Return the object associated with ADDR in MAP. */
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void *addrmap_find (struct addrmap *map, CORE_ADDR addr);
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/* Create a fixed address map which is a copy of the mutable address
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map ORIGINAL. Allocate entries in OBSTACK. */
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struct addrmap *addrmap_create_fixed (struct addrmap *original,
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struct obstack *obstack);
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/* Relocate all the addresses in MAP by OFFSET. (This can be applied
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to either mutable or immutable maps.) */
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void addrmap_relocate (struct addrmap *map, CORE_ADDR offset);
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#endif /* ADDRMAP_H */
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