mirror of
https://sourceware.org/git/binutils-gdb.git
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aac3cc8258
In subsequent patches, it's handy if gdb.Block is hashable, so it can be stored in a set or a dictionary. However, doing this in a straightforward way is not really possible, because a block isn't truly immutable -- it can be invalidated. And, while this isn't a real problem for my use case (in DAP the maps are only used during a single stop), it seemed error-prone. This patch instead takes the approach of using the gdb.Block's own object identity to allow hashing. This seems fine because the contents don't affect the hashing. In order for this to work, though, the blocks have to be memoized -- two requests for the same block must return the same object. This also allows (actually, requires) the simplification of the rich-compare method for blocks. Reviewed-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>
616 lines
16 KiB
C
616 lines
16 KiB
C
/* Python interface to blocks.
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Copyright (C) 2008-2024 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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#include "block.h"
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#include "dictionary.h"
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#include "symtab.h"
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#include "python-internal.h"
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#include "objfiles.h"
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struct block_object {
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PyObject_HEAD
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/* The GDB block structure that represents a frame's code block. */
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const struct block *block;
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/* The backing object file. There is no direct relationship in GDB
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between a block and an object file. When a block is created also
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store a pointer to the object file for later use. */
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struct objfile *objfile;
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};
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struct block_syms_iterator_object {
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PyObject_HEAD
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/* The block. */
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const struct block *block;
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/* The iterator for that block. */
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struct block_iterator iter;
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/* Has the iterator been initialized flag. */
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int initialized_p;
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/* Pointer back to the original source block object. Needed to
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check if the block is still valid, and has not been invalidated
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when an object file has been freed. */
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block_object *source;
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};
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/* Require a valid block. All access to block_object->block should be
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gated by this call. */
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#define BLPY_REQUIRE_VALID(block_obj, block) \
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do { \
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block = block_object_to_block (block_obj); \
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if (block == NULL) \
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{ \
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PyErr_SetString (PyExc_RuntimeError, \
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_("Block is invalid.")); \
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return NULL; \
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} \
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} while (0)
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/* Require a valid block. This macro is called during block iterator
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creation, and at each next call. */
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#define BLPY_ITER_REQUIRE_VALID(block_obj) \
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do { \
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if (block_obj->block == NULL) \
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{ \
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PyErr_SetString (PyExc_RuntimeError, \
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_("Source block for iterator is invalid.")); \
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return NULL; \
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} \
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} while (0)
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extern PyTypeObject block_syms_iterator_object_type
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CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("block_syms_iterator_object");
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static const registry<objfile>::key<htab, htab_deleter>
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blpy_objfile_data_key;
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static PyObject *
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blpy_iter (PyObject *self)
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{
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block_syms_iterator_object *block_iter_obj;
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const struct block *block = NULL;
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BLPY_REQUIRE_VALID (self, block);
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block_iter_obj = PyObject_New (block_syms_iterator_object,
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&block_syms_iterator_object_type);
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if (block_iter_obj == NULL)
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return NULL;
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block_iter_obj->block = block;
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block_iter_obj->initialized_p = 0;
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Py_INCREF (self);
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block_iter_obj->source = (block_object *) self;
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return (PyObject *) block_iter_obj;
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}
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static PyObject *
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blpy_get_start (PyObject *self, void *closure)
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{
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const struct block *block = NULL;
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BLPY_REQUIRE_VALID (self, block);
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return gdb_py_object_from_ulongest (block->start ()).release ();
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}
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static PyObject *
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blpy_get_end (PyObject *self, void *closure)
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{
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const struct block *block = NULL;
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BLPY_REQUIRE_VALID (self, block);
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return gdb_py_object_from_ulongest (block->end ()).release ();
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}
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static PyObject *
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blpy_get_function (PyObject *self, void *closure)
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{
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struct symbol *sym;
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const struct block *block;
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BLPY_REQUIRE_VALID (self, block);
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sym = block->function ();
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if (sym)
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return symbol_to_symbol_object (sym);
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Py_RETURN_NONE;
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}
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static PyObject *
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blpy_get_superblock (PyObject *self, void *closure)
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{
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const struct block *block;
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const struct block *super_block;
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block_object *self_obj = (block_object *) self;
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BLPY_REQUIRE_VALID (self, block);
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super_block = block->superblock ();
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if (super_block)
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return block_to_block_object (super_block, self_obj->objfile);
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Py_RETURN_NONE;
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}
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/* Return the global block associated to this block. */
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static PyObject *
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blpy_get_global_block (PyObject *self, void *closure)
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{
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const struct block *block;
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const struct block *global_block;
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block_object *self_obj = (block_object *) self;
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BLPY_REQUIRE_VALID (self, block);
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global_block = block->global_block ();
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return block_to_block_object (global_block,
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self_obj->objfile);
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}
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/* Return the static block associated to this block. Return None
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if we cannot get the static block (this is the global block). */
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static PyObject *
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blpy_get_static_block (PyObject *self, void *closure)
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{
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const struct block *block;
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const struct block *static_block;
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block_object *self_obj = (block_object *) self;
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BLPY_REQUIRE_VALID (self, block);
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if (block->superblock () == NULL)
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Py_RETURN_NONE;
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static_block = block->static_block ();
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return block_to_block_object (static_block, self_obj->objfile);
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}
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/* Implementation of gdb.Block.is_global (self) -> Boolean.
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Returns True if this block object is a global block. */
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static PyObject *
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blpy_is_global (PyObject *self, void *closure)
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{
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const struct block *block;
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BLPY_REQUIRE_VALID (self, block);
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if (block->superblock ())
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Py_RETURN_FALSE;
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Py_RETURN_TRUE;
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}
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/* Implementation of gdb.Block.is_static (self) -> Boolean.
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Returns True if this block object is a static block. */
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static PyObject *
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blpy_is_static (PyObject *self, void *closure)
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{
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const struct block *block;
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BLPY_REQUIRE_VALID (self, block);
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if (block->superblock () != NULL
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&& block->superblock ()->superblock () == NULL)
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Py_RETURN_TRUE;
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Py_RETURN_FALSE;
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}
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/* Given a string, returns the gdb.Symbol representing that symbol in this
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block. If such a symbol does not exist, returns NULL with a Python
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exception. */
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static PyObject *
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blpy_getitem (PyObject *self, PyObject *key)
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{
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const struct block *block;
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BLPY_REQUIRE_VALID (self, block);
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gdb::unique_xmalloc_ptr<char> name = python_string_to_host_string (key);
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if (name == nullptr)
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return nullptr;
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lookup_name_info lookup_name (name.get(), symbol_name_match_type::FULL);
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/* We use an iterator instead of block_lookup_symbol so that we can
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look up symbols irrespective of the domain, matching the
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iterator. It would be confusing if the iterator returns symbols
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you can't find via getitem. */
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for (struct symbol *sym : block_iterator_range (block, &lookup_name))
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{
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/* Just stop at the first match */
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return symbol_to_symbol_object (sym);
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}
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PyErr_SetObject (PyExc_KeyError, key);
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return nullptr;
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}
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/* Deleter function for the hash table. */
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static void
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block_object_del (void *obj)
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{
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block_object *block = (block_object *) obj;
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block->block = nullptr;
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block->objfile = nullptr;
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}
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/* Hash function for the hash table. */
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static hashval_t
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block_object_hash (const void *obj)
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{
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const block_object *block = (const block_object *) obj;
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return htab_hash_pointer (block->block);
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}
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/* Equality function for the hash table. Note that searches must be
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done with a plain block. */
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static int
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block_object_eq (const void *a, const void *b)
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{
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const block_object *blocka = (const block_object *) a;
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const block *blockb = (const block *) b;
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return blocka->block == blockb;
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}
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/* Called when a gdb.Block is destroyed. This removes it from the
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hash. */
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static void
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blpy_dealloc (PyObject *obj)
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{
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block_object *block = (block_object *) obj;
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if (block->objfile != nullptr)
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{
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htab_t table = blpy_objfile_data_key.get (block->objfile);
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hashval_t hash = block_object_hash (block);
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/* This will clear the contents of the block as a side
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effect. */
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htab_remove_elt_with_hash (table, block->block, hash);
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}
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Py_TYPE (obj)->tp_free (obj);
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}
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/* Create a new block object (gdb.Block) that encapsulates the struct
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block object from GDB. */
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PyObject *
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block_to_block_object (const struct block *block, struct objfile *objfile)
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{
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htab_t table = blpy_objfile_data_key.get (objfile);
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if (table == nullptr)
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{
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table = htab_create_alloc (10, block_object_hash, block_object_eq,
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block_object_del, xcalloc, xfree);
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blpy_objfile_data_key.set (objfile, table);
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}
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hashval_t hash = htab_hash_pointer (block);
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block_object *result = (block_object *) htab_find_with_hash (table, block,
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hash);
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if (result != nullptr)
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{
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PyObject *py_result = (PyObject *) result;
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Py_INCREF (py_result);
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return py_result;
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}
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result = PyObject_New (block_object, &block_object_type);
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result->block = block;
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result->objfile = objfile;
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void **slot = htab_find_slot_with_hash (table, block, hash, INSERT);
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*slot = result;
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return (PyObject *) result;
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}
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/* Return struct block reference that is wrapped by this object. */
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const struct block *
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block_object_to_block (PyObject *obj)
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{
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if (! PyObject_TypeCheck (obj, &block_object_type))
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return NULL;
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return ((block_object *) obj)->block;
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}
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/* Return a reference to the block iterator. */
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static PyObject *
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blpy_block_syms_iter (PyObject *self)
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{
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block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) self;
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BLPY_ITER_REQUIRE_VALID (iter_obj->source);
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Py_INCREF (self);
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return self;
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}
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/* Return the next symbol in the iteration through the block's
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dictionary. */
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static PyObject *
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blpy_block_syms_iternext (PyObject *self)
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{
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block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) self;
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struct symbol *sym;
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BLPY_ITER_REQUIRE_VALID (iter_obj->source);
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if (!iter_obj->initialized_p)
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{
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sym = block_iterator_first (iter_obj->block, &(iter_obj->iter));
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iter_obj->initialized_p = 1;
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}
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else
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sym = block_iterator_next (&(iter_obj->iter));
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if (sym == NULL)
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{
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PyErr_SetString (PyExc_StopIteration, _("Symbol is null."));
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return NULL;
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}
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return symbol_to_symbol_object (sym);
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}
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static void
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blpy_block_syms_dealloc (PyObject *obj)
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{
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block_syms_iterator_object *iter_obj = (block_syms_iterator_object *) obj;
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Py_XDECREF (iter_obj->source);
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Py_TYPE (obj)->tp_free (obj);
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}
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/* Implementation of gdb.Block.is_valid (self) -> Boolean.
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Returns True if this block object still exists in GDB. */
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static PyObject *
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blpy_is_valid (PyObject *self, PyObject *args)
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{
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const struct block *block;
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block = block_object_to_block (self);
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if (block == NULL)
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Py_RETURN_FALSE;
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Py_RETURN_TRUE;
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}
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/* Implementation of gdb.BlockIterator.is_valid (self) -> Boolean.
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Returns True if this block iterator object still exists in GDB */
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static PyObject *
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blpy_iter_is_valid (PyObject *self, PyObject *args)
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{
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block_syms_iterator_object *iter_obj =
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(block_syms_iterator_object *) self;
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if (iter_obj->source->block == NULL)
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Py_RETURN_FALSE;
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Py_RETURN_TRUE;
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}
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/* __repr__ implementation for gdb.Block. */
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static PyObject *
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blpy_repr (PyObject *self)
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{
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const auto block = block_object_to_block (self);
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if (block == nullptr)
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return gdb_py_invalid_object_repr (self);
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const auto name = block->function () ?
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block->function ()->print_name () : "<anonymous>";
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std::string str;
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unsigned int written_symbols = 0;
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const int len = mdict_size (block->multidict ());
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static constexpr int SYMBOLS_TO_SHOW = 5;
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for (struct symbol *symbol : block_iterator_range (block))
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{
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if (written_symbols == SYMBOLS_TO_SHOW)
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{
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const int remaining = len - SYMBOLS_TO_SHOW;
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if (remaining == 1)
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str += string_printf ("... (%d more symbol)", remaining);
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else
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str += string_printf ("... (%d more symbols)", remaining);
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break;
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}
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str += symbol->print_name ();
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if (++written_symbols < len)
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str += ", ";
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}
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return PyUnicode_FromFormat ("<%s %s {%s}>", Py_TYPE (self)->tp_name,
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name, str.c_str ());
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}
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/* Hash function for block objects. */
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static Py_hash_t
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blpy_hash (PyObject *self)
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{
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/* Python doesn't really expose its pointer hash function, so we use
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our own. */
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Py_hash_t result = (Py_hash_t) htab_hash_pointer (self);
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/* -1 has a special meaning for Python. */
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if (result == -1)
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result = -2;
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return result;
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}
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/* Implements the equality comparison for Block objects. All other
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comparison operators will throw NotImplemented, as they aren't
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valid for blocks. */
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static PyObject *
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blpy_richcompare (PyObject *self, PyObject *other, int op)
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{
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if (!PyObject_TypeCheck (other, &block_object_type)
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|| (op != Py_EQ && op != Py_NE))
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{
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Py_INCREF (Py_NotImplemented);
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return Py_NotImplemented;
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}
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bool expected = self == other;
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bool equal = op == Py_EQ;
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return PyBool_FromLong (equal == expected);
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}
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static int CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION
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gdbpy_initialize_blocks (void)
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{
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block_object_type.tp_new = PyType_GenericNew;
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if (PyType_Ready (&block_object_type) < 0)
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return -1;
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block_syms_iterator_object_type.tp_new = PyType_GenericNew;
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if (PyType_Ready (&block_syms_iterator_object_type) < 0)
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return -1;
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if (gdb_pymodule_addobject (gdb_module, "Block",
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(PyObject *) &block_object_type) < 0)
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return -1;
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return gdb_pymodule_addobject (gdb_module, "BlockIterator",
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(PyObject *) &block_syms_iterator_object_type);
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}
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GDBPY_INITIALIZE_FILE (gdbpy_initialize_blocks);
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static PyMethodDef block_object_methods[] = {
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{ "is_valid", blpy_is_valid, METH_NOARGS,
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"is_valid () -> Boolean.\n\
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Return true if this block is valid, false if not." },
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{NULL} /* Sentinel */
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};
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static gdb_PyGetSetDef block_object_getset[] = {
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{ "start", blpy_get_start, NULL, "Start address of the block.", NULL },
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{ "end", blpy_get_end, NULL, "End address of the block.", NULL },
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{ "function", blpy_get_function, NULL,
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"Symbol that names the block, or None.", NULL },
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{ "superblock", blpy_get_superblock, NULL,
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"Block containing the block, or None.", NULL },
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{ "global_block", blpy_get_global_block, NULL,
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"Block containing the global block.", NULL },
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{ "static_block", blpy_get_static_block, NULL,
|
||
"Block containing the static block.", NULL },
|
||
{ "is_static", blpy_is_static, NULL,
|
||
"Whether this block is a static block.", NULL },
|
||
{ "is_global", blpy_is_global, NULL,
|
||
"Whether this block is a global block.", NULL },
|
||
{ NULL } /* Sentinel */
|
||
};
|
||
|
||
static PyMappingMethods block_object_as_mapping = {
|
||
NULL,
|
||
blpy_getitem,
|
||
NULL
|
||
};
|
||
|
||
PyTypeObject block_object_type = {
|
||
PyVarObject_HEAD_INIT (NULL, 0)
|
||
"gdb.Block", /*tp_name*/
|
||
sizeof (block_object), /*tp_basicsize*/
|
||
0, /*tp_itemsize*/
|
||
blpy_dealloc, /*tp_dealloc*/
|
||
0, /*tp_print*/
|
||
0, /*tp_getattr*/
|
||
0, /*tp_setattr*/
|
||
0, /*tp_compare*/
|
||
blpy_repr, /*tp_repr*/
|
||
0, /*tp_as_number*/
|
||
0, /*tp_as_sequence*/
|
||
&block_object_as_mapping, /*tp_as_mapping*/
|
||
blpy_hash, /*tp_hash */
|
||
0, /*tp_call*/
|
||
0, /*tp_str*/
|
||
0, /*tp_getattro*/
|
||
0, /*tp_setattro*/
|
||
0, /*tp_as_buffer*/
|
||
Py_TPFLAGS_DEFAULT, /*tp_flags*/
|
||
"GDB block object", /* tp_doc */
|
||
0, /* tp_traverse */
|
||
0, /* tp_clear */
|
||
blpy_richcompare, /* tp_richcompare */
|
||
0, /* tp_weaklistoffset */
|
||
blpy_iter, /* tp_iter */
|
||
0, /* tp_iternext */
|
||
block_object_methods, /* tp_methods */
|
||
0, /* tp_members */
|
||
block_object_getset /* tp_getset */
|
||
};
|
||
|
||
static PyMethodDef block_iterator_object_methods[] = {
|
||
{ "is_valid", blpy_iter_is_valid, METH_NOARGS,
|
||
"is_valid () -> Boolean.\n\
|
||
Return true if this block iterator is valid, false if not." },
|
||
{NULL} /* Sentinel */
|
||
};
|
||
|
||
PyTypeObject block_syms_iterator_object_type = {
|
||
PyVarObject_HEAD_INIT (NULL, 0)
|
||
"gdb.BlockIterator", /*tp_name*/
|
||
sizeof (block_syms_iterator_object), /*tp_basicsize*/
|
||
0, /*tp_itemsize*/
|
||
blpy_block_syms_dealloc, /*tp_dealloc*/
|
||
0, /*tp_print*/
|
||
0, /*tp_getattr*/
|
||
0, /*tp_setattr*/
|
||
0, /*tp_compare*/
|
||
0, /*tp_repr*/
|
||
0, /*tp_as_number*/
|
||
0, /*tp_as_sequence*/
|
||
0, /*tp_as_mapping*/
|
||
0, /*tp_hash */
|
||
0, /*tp_call*/
|
||
0, /*tp_str*/
|
||
0, /*tp_getattro*/
|
||
0, /*tp_setattro*/
|
||
0, /*tp_as_buffer*/
|
||
Py_TPFLAGS_DEFAULT, /*tp_flags*/
|
||
"GDB block syms iterator object", /*tp_doc */
|
||
0, /*tp_traverse */
|
||
0, /*tp_clear */
|
||
0, /*tp_richcompare */
|
||
0, /*tp_weaklistoffset */
|
||
blpy_block_syms_iter, /*tp_iter */
|
||
blpy_block_syms_iternext, /*tp_iternext */
|
||
block_iterator_object_methods /*tp_methods */
|
||
};
|