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Fix splay tree KEY leak detected in GDB test gdb.base/macscp.exp

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When a node is removed from a splay tree, the splay tree was
not using the function splay_tree_delete_key_fn to release the key.
This was causing a leak, fixed by Tom Tromey.

This patch fixes another key leak, that happens when a key equal to
a key already present is inserted.  In such a case, we have to release
the old KEY.
Note that this is based on the assumption that the caller always
allocates a new KEY when doing an insert.

Also, clarify the documentation about when the release functions are
called.

2019-02-11  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* splay-tree.h (splay_tree_delete_key_fn): Update comment.
	(splay_tree_delete_value_fn): Likewise.

libiberty/ChangeLog
2019-02-11  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* splay-tree.c (splay_tree_insert): Also release old KEY in case
	of insertion of a key equal to an already present key.
	(splay_tree_new_typed_alloc): Update comment.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@268793 138bc75d-0d04-0410-961f-82ee72b054a4
This commit is contained in:
tromey 2019-02-12 13:02:48 +00:00 committed by Tom Tromey
parent 04d7fa2132
commit e20773049f
4 changed files with 30 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/ChangeLog
View File

@ -1,3 +1,8 @@
2019-02-11 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* splay-tree.h (splay_tree_delete_key_fn): Update comment.
(splay_tree_delete_value_fn): Likewise.
2019-01-31 Andreas Krebbel <krebbel@linux.ibm.com>
* opcode/s390.h (enum s390_opcode_cpu_val): Add

11
include/splay-tree.h
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@ -58,11 +58,18 @@ typedef struct splay_tree_node_s *splay_tree_node;
typedef int (*splay_tree_compare_fn) (splay_tree_key, splay_tree_key);
/* The type of a function used to deallocate any resources associated
with the key. */
with the key. If you provide this function, the splay tree
will take the ownership of the memory of the splay_tree_key arg
of splay_tree_insert. This function is called to release the keys
present in the tree when calling splay_tree_delete or splay_tree_remove.
If splay_tree_insert is called with a key equal to a key already
present in the tree, the old key and old value will be released. */
typedef void (*splay_tree_delete_key_fn) (splay_tree_key);
/* The type of a function used to deallocate any resources associated
with the value. */
with the value. If you provide this function, the memory of the
splay_tree_value arg of splay_tree_insert is managed similarly to
the splay_tree_key memory: see splay_tree_delete_key_fn. */
typedef void (*splay_tree_delete_value_fn) (splay_tree_value);
/* The type of a function used to iterate over the tree. */

6
libiberty/ChangeLog
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@ -1,3 +1,9 @@
2019-02-11 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* splay-tree.c (splay_tree_insert): Also release old KEY in case
of insertion of a key equal to an already present key.
(splay_tree_new_typed_alloc): Update comment.
2019-01-21 Tom Tromey <tom@tromey.com>
* splay-tree.c (splay_tree_remove): Delete the key if necessary.

13
libiberty/splay-tree.c
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@ -318,7 +318,11 @@ different types need to be allocated with different allocators.
The splay tree will use @var{compare_fn} to compare nodes,
@var{delete_key_fn} to deallocate keys, and @var{delete_value_fn} to
deallocate values.
deallocate values. Keys and values will be deallocated when the
tree is deleted using splay_tree_delete or when a node is removed
using splay_tree_remove. splay_tree_insert will release the previously
inserted key and value using @var{delete_key_fn} and @var{delete_value_fn}
if the inserted key is already found in the tree.
@end deftypefn
@ -372,10 +376,13 @@ splay_tree_insert (splay_tree sp, splay_tree_key key, splay_tree_value value)
if (sp->root && comparison == 0)
{
/* If the root of the tree already has the indicated KEY, just
replace the value with VALUE. */
/* If the root of the tree already has the indicated KEY, delete
the old key and old value, and replace them with KEY and VALUE. */
if (sp->delete_key)
(*sp->delete_key) (sp->root->key);
if (sp->delete_value)
(*sp->delete_value)(sp->root->value);
sp->root->key = key;
sp->root->value = value;
}
else