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-rw-r--r--libmudflap/mf-runtime.c659
1 files changed, 618 insertions, 41 deletions
diff --git a/libmudflap/mf-runtime.c b/libmudflap/mf-runtime.c
index 8b1cc749c9e..e0a37a437dc 100644
--- a/libmudflap/mf-runtime.c
+++ b/libmudflap/mf-runtime.c
@@ -2,6 +2,8 @@
Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
Contributed by Frank Ch. Eigler <fche@redhat.com>
and Graydon Hoare <graydon@redhat.com>
+ Splay Tree code originally by Mark Mitchell <mark@markmitchell.com>,
+ adapted from libiberty.
This file is part of GCC.
@@ -67,10 +69,63 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
#include "mf-runtime.h"
#include "mf-impl.h"
-#include "splay-tree.h"
/* ------------------------------------------------------------------------ */
+/* Splay-tree implementation. */
+
+typedef uintptr_t mfsplay_tree_key;
+typedef void *mfsplay_tree_value;
+
+/* Forward declaration for a node in the tree. */
+typedef struct mfsplay_tree_node_s *mfsplay_tree_node;
+
+/* The type of a function used to iterate over the tree. */
+typedef int (*mfsplay_tree_foreach_fn) (mfsplay_tree_node, void *);
+
+/* The nodes in the splay tree. */
+struct mfsplay_tree_node_s
+{
+ /* Data. */
+ mfsplay_tree_key key;
+ mfsplay_tree_value value;
+ /* Children. */
+ mfsplay_tree_node left;
+ mfsplay_tree_node right;
+ /* XXX: The addition of a parent pointer may eliminate some recursion. */
+};
+
+/* The splay tree itself. */
+struct mfsplay_tree_s
+{
+ /* The root of the tree. */
+ mfsplay_tree_node root;
+
+ /* The last key value for which the tree has been splayed, but not
+ since modified. */
+ mfsplay_tree_key last_splayed_key;
+ int last_splayed_key_p;
+
+ /* Statistics. */
+ unsigned num_keys;
+
+ /* Traversal recursion control flags. */
+ unsigned max_depth;
+ unsigned depth;
+ unsigned rebalance_p;
+};
+typedef struct mfsplay_tree_s *mfsplay_tree;
+
+static mfsplay_tree mfsplay_tree_new (void);
+static mfsplay_tree_node mfsplay_tree_insert (mfsplay_tree, mfsplay_tree_key, mfsplay_tree_value);
+static void mfsplay_tree_remove (mfsplay_tree, mfsplay_tree_key);
+static mfsplay_tree_node mfsplay_tree_lookup (mfsplay_tree, mfsplay_tree_key);
+static mfsplay_tree_node mfsplay_tree_predecessor (mfsplay_tree, mfsplay_tree_key);
+static mfsplay_tree_node mfsplay_tree_successor (mfsplay_tree, mfsplay_tree_key);
+static int mfsplay_tree_foreach (mfsplay_tree, mfsplay_tree_foreach_fn, void *);
+static void mfsplay_tree_rebalance (mfsplay_tree sp);
+
+/* ------------------------------------------------------------------------ */
/* Utility macros */
#define CTOR __attribute__ ((constructor))
@@ -136,7 +191,11 @@ pthread_mutex_t __mf_biglock =
the libmudflap.la (no threading support) can diagnose whether
the application is linked with -lpthread. See __mf_usage() below. */
#if HAVE_PTHREAD_H
+#ifdef _POSIX_THREADS
#pragma weak pthread_join
+#else
+#define pthread_join NULL
+#endif
const void *threads_active_p = (void *) pthread_join;
#endif
@@ -202,7 +261,7 @@ static __mf_object_t *__mf_object_cemetary[__MF_TYPE_MAX_CEM+1][__MF_PERSIST_MAX
/* ------------------------------------------------------------------------ */
/* Forward function declarations */
-static void __mf_init () CTOR;
+void __mf_init () CTOR;
static void __mf_sigusr1_respond ();
static unsigned __mf_find_objects (uintptr_t ptr_low, uintptr_t ptr_high,
__mf_object_t **objs, unsigned max_objs);
@@ -213,7 +272,7 @@ static unsigned __mf_find_dead_objects (uintptr_t ptr_low, uintptr_t ptr_high,
static void __mf_adapt_cache ();
static void __mf_describe_object (__mf_object_t *obj);
static unsigned __mf_watch_or_not (void *ptr, size_t sz, char flag);
-static splay_tree __mf_object_tree (int type);
+static mfsplay_tree __mf_object_tree (int type);
static void __mf_link_object (__mf_object_t *node);
static void __mf_unlink_object (__mf_object_t *node);
@@ -233,6 +292,7 @@ __mf_set_default_options ()
__mf_opts.persistent_count = 100;
__mf_opts.crumple_zone = 32;
__mf_opts.backtrace = 4;
+ __mf_opts.timestamps = 1;
__mf_opts.mudflap_mode = mode_check;
__mf_opts.violation_mode = viol_nop;
__mf_opts.heur_std_data = 1;
@@ -309,6 +369,12 @@ options [] =
{"abbreviate",
"abbreviate repetitive listings",
set_option, 1, &__mf_opts.abbreviate},
+ {"timestamps",
+ "track object lifetime timestamps",
+ set_option, 1, &__mf_opts.timestamps},
+ {"ignore-reads",
+ "ignore read accesses - assume okay",
+ set_option, 1, &__mf_opts.ignore_reads},
{"wipe-stack",
"wipe stack objects at unwind",
set_option, 1, &__mf_opts.wipe_stack},
@@ -365,7 +431,7 @@ __mf_usage ()
fprintf (stderr,
"This is a %s%sGCC \"mudflap\" memory-checked binary.\n"
- "Mudflap is Copyright (C) 2002-2003 Free Software Foundation, Inc.\n"
+ "Mudflap is Copyright (C) 2002-2004 Free Software Foundation, Inc.\n"
"\n"
"The mudflap code can be controlled by an environment variable:\n"
"\n"
@@ -600,22 +666,26 @@ struct __mf_dynamic_entry __mf_dynamic [] =
/* ------------------------------------------------------------------------ */
/* Lookup & manage automatic initialization of the five or so splay trees. */
-static splay_tree
+static mfsplay_tree
__mf_object_tree (int type)
{
- static splay_tree trees [__MF_TYPE_MAX+1];
+ static mfsplay_tree trees [__MF_TYPE_MAX+1];
assert (type >= 0 && type <= __MF_TYPE_MAX);
if (UNLIKELY (trees[type] == NULL))
- trees[type] = splay_tree_new (splay_tree_compare_pointers, NULL, NULL);
+ trees[type] = mfsplay_tree_new ();
return trees[type];
}
-void
+/* not static */void
__mf_init ()
{
char *ov = 0;
+ /* Return if initialization has already been done. */
+ if (LIKELY (__mf_starting_p == 0))
+ return;
+
/* This initial bootstrap phase requires that __mf_starting_p = 1. */
#ifdef PIC
__mf_resolve_dynamics ();
@@ -708,6 +778,12 @@ void __mf_fini ()
{
TRACE ("__mf_fini\n");
__mfu_report ();
+
+#ifndef PIC
+/* Since we didn't populate the tree for allocations in constructors
+ before __mf_init, we cannot check destructors after __mf_fini. */
+ __mf_opts.mudflap_mode = mode_nop;
+#endif
}
@@ -744,8 +820,13 @@ void __mfu_check (void *ptr, size_t sz, int type, const char *location)
switch (__mf_opts.mudflap_mode)
{
case mode_nop:
- entry->low = MINPTR;
- entry->high = MAXPTR;
+ /* It is tempting to poison the cache here similarly to
+ mode_populate. However that eliminates a valuable
+ distinction between these two modes. mode_nop is useful to
+ let a user count & trace every single check / registration
+ call. mode_populate is useful to let a program run fast
+ while unchecked.
+ */
judgement = 1;
break;
@@ -909,7 +990,8 @@ __mf_insert_new_object (uintptr_t low, uintptr_t high, int type,
new_obj->name = name;
new_obj->alloc_pc = pc;
#if HAVE_GETTIMEOFDAY
- gettimeofday (& new_obj->alloc_time, NULL);
+ if (__mf_opts.timestamps)
+ gettimeofday (& new_obj->alloc_time, NULL);
#endif
#if LIBMUDFLAPTH
new_obj->alloc_thread = pthread_self ();
@@ -1149,7 +1231,8 @@ __mfu_unregister (void *ptr, size_t sz, int type)
old_obj->deallocated_p = 1;
old_obj->dealloc_pc = (uintptr_t) __builtin_return_address (0);
#if HAVE_GETTIMEOFDAY
- gettimeofday (& old_obj->dealloc_time, NULL);
+ if (__mf_opts.timestamps)
+ gettimeofday (& old_obj->dealloc_time, NULL);
#endif
#ifdef LIBMUDFLAPTH
old_obj->dealloc_thread = pthread_self ();
@@ -1232,7 +1315,7 @@ struct tree_stats
static int
-__mf_adapt_cache_fn (splay_tree_node n, void *param)
+__mf_adapt_cache_fn (mfsplay_tree_node n, void *param)
{
__mf_object_t *obj = (__mf_object_t *) n->value;
struct tree_stats *s = (struct tree_stats *) param;
@@ -1289,11 +1372,11 @@ __mf_adapt_cache ()
memset (&s, 0, sizeof (s));
- splay_tree_foreach (__mf_object_tree (__MF_TYPE_HEAP), __mf_adapt_cache_fn, (void *) & s);
- splay_tree_foreach (__mf_object_tree (__MF_TYPE_HEAP_I), __mf_adapt_cache_fn, (void *) & s);
- splay_tree_foreach (__mf_object_tree (__MF_TYPE_STACK), __mf_adapt_cache_fn, (void *) & s);
- splay_tree_foreach (__mf_object_tree (__MF_TYPE_STATIC), __mf_adapt_cache_fn, (void *) & s);
- splay_tree_foreach (__mf_object_tree (__MF_TYPE_GUESS), __mf_adapt_cache_fn, (void *) & s);
+ mfsplay_tree_foreach (__mf_object_tree (__MF_TYPE_HEAP), __mf_adapt_cache_fn, (void *) & s);
+ mfsplay_tree_foreach (__mf_object_tree (__MF_TYPE_HEAP_I), __mf_adapt_cache_fn, (void *) & s);
+ mfsplay_tree_foreach (__mf_object_tree (__MF_TYPE_STACK), __mf_adapt_cache_fn, (void *) & s);
+ mfsplay_tree_foreach (__mf_object_tree (__MF_TYPE_STATIC), __mf_adapt_cache_fn, (void *) & s);
+ mfsplay_tree_foreach (__mf_object_tree (__MF_TYPE_GUESS), __mf_adapt_cache_fn, (void *) & s);
/* Maybe we're dealing with funny aging/adaptation parameters, or an
empty tree. Just leave the cache alone in such cases, rather
@@ -1363,11 +1446,11 @@ __mf_find_objects2 (uintptr_t ptr_low, uintptr_t ptr_high,
__mf_object_t **objs, unsigned max_objs, int type)
{
unsigned count = 0;
- splay_tree t = __mf_object_tree (type);
- splay_tree_key k = (splay_tree_key) ptr_low;
+ mfsplay_tree t = __mf_object_tree (type);
+ mfsplay_tree_key k = (mfsplay_tree_key) ptr_low;
int direction;
- splay_tree_node n = splay_tree_lookup (t, k);
+ mfsplay_tree_node n = mfsplay_tree_lookup (t, k);
/* An exact match for base address implies a hit. */
if (n != NULL)
{
@@ -1380,13 +1463,13 @@ __mf_find_objects2 (uintptr_t ptr_low, uintptr_t ptr_high,
for (direction = 0; direction < 2; direction ++)
{
/* Reset search origin. */
- k = (splay_tree_key) ptr_low;
+ k = (mfsplay_tree_key) ptr_low;
while (1)
{
__mf_object_t *obj;
- n = (direction == 0 ? splay_tree_predecessor (t, k) : splay_tree_successor (t, k));
+ n = (direction == 0 ? mfsplay_tree_successor (t, k) : mfsplay_tree_predecessor (t, k));
if (n == NULL) break;
obj = (__mf_object_t *) n->value;
@@ -1397,7 +1480,7 @@ __mf_find_objects2 (uintptr_t ptr_low, uintptr_t ptr_high,
objs[count] = (__mf_object_t *) n->value;
count ++;
- k = (splay_tree_key) obj->low;
+ k = (mfsplay_tree_key) obj->low;
}
}
@@ -1439,8 +1522,8 @@ __mf_find_objects (uintptr_t ptr_low, uintptr_t ptr_high,
static void
__mf_link_object (__mf_object_t *node)
{
- splay_tree t = __mf_object_tree (node->type);
- splay_tree_insert (t, (splay_tree_key) node->low, (splay_tree_value) node);
+ mfsplay_tree t = __mf_object_tree (node->type);
+ mfsplay_tree_insert (t, (mfsplay_tree_key) node->low, (mfsplay_tree_value) node);
}
/* __mf_unlink_object */
@@ -1448,8 +1531,8 @@ __mf_link_object (__mf_object_t *node)
static void
__mf_unlink_object (__mf_object_t *node)
{
- splay_tree t = __mf_object_tree (node->type);
- splay_tree_remove (t, (splay_tree_key) node->low);
+ mfsplay_tree t = __mf_object_tree (node->type);
+ mfsplay_tree_remove (t, (mfsplay_tree_key) node->low);
}
/* __mf_find_dead_objects */
@@ -1601,7 +1684,7 @@ __mf_describe_object (__mf_object_t *obj)
static int
-__mf_report_leaks_fn (splay_tree_node n, void *param)
+__mf_report_leaks_fn (mfsplay_tree_node n, void *param)
{
__mf_object_t *node = (__mf_object_t *) n->value;
unsigned *count = (unsigned *) param;
@@ -1621,9 +1704,9 @@ __mf_report_leaks ()
{
unsigned count = 0;
- (void) splay_tree_foreach (__mf_object_tree (__MF_TYPE_HEAP),
+ (void) mfsplay_tree_foreach (__mf_object_tree (__MF_TYPE_HEAP),
__mf_report_leaks_fn, & count);
- (void) splay_tree_foreach (__mf_object_tree (__MF_TYPE_HEAP_I),
+ (void) mfsplay_tree_foreach (__mf_object_tree (__MF_TYPE_HEAP_I),
__mf_report_leaks_fn, & count);
return count;
@@ -1835,7 +1918,7 @@ __mf_violation (void *ptr, size_t sz, uintptr_t pc,
{
unsigned dead_p;
unsigned num_helpful = 0;
- struct timeval now;
+ struct timeval now = { 0, 0 };
#if HAVE_GETTIMEOFDAY
gettimeofday (& now, NULL);
#endif
@@ -2140,25 +2223,519 @@ __assert_fail (const char *msg, const char *file, unsigned line, const char *fun
-
-
-/* #include the generic splay tree implementation from libiberty here, to
- ensure that it uses our memory allocation primitives. */
+/* Adapted splay tree code, originally from libiberty. It has been
+ specialized for libmudflap as requested by RMS. */
static void
-splay_tree_free (void *p)
+mfsplay_tree_free (void *p)
{
DECLARE (void, free, void *p);
CALL_REAL (free, p);
}
static void *
-splay_tree_xmalloc (size_t s)
+mfsplay_tree_xmalloc (size_t s)
{
DECLARE (void *, malloc, size_t s);
return CALL_REAL (malloc, s);
}
-#define free(z) splay_tree_free(z)
-#define xmalloc(z) splay_tree_xmalloc(z)
-#include "splay-tree.c"
+
+static void mfsplay_tree_splay (mfsplay_tree, mfsplay_tree_key);
+static mfsplay_tree_node mfsplay_tree_splay_helper (mfsplay_tree,
+ mfsplay_tree_key,
+ mfsplay_tree_node *,
+ mfsplay_tree_node *,
+ mfsplay_tree_node *);
+static void *mfsplay_tree_xmalloc (size_t size);
+static void mfsplay_tree_free (void *object);
+
+
+
+/* Inline comparison function specialized for libmudflap's key type. */
+static inline int
+compare_uintptr_t (mfsplay_tree_key k1, mfsplay_tree_key k2)
+{
+ if ((uintptr_t) k1 < (uintptr_t) k2)
+ return -1;
+ else if ((uintptr_t) k1 > (uintptr_t) k2)
+ return 1;
+ else
+ return 0;
+}
+
+
+/* Help splay SP around KEY. PARENT and GRANDPARENT are the parent
+ and grandparent, respectively, of NODE. */
+
+static mfsplay_tree_node
+mfsplay_tree_splay_helper (mfsplay_tree sp,
+ mfsplay_tree_key key,
+ mfsplay_tree_node * node,
+ mfsplay_tree_node * parent,
+ mfsplay_tree_node * grandparent)
+{
+ mfsplay_tree_node *next;
+ mfsplay_tree_node n;
+ int comparison;
+
+ n = *node;
+
+ if (!n)
+ return *parent;
+
+ comparison = compare_uintptr_t (key, n->key);
+
+ if (comparison == 0)
+ /* We've found the target. */
+ next = 0;
+ else if (comparison < 0)
+ /* The target is to the left. */
+ next = &n->left;
+ else
+ /* The target is to the right. */
+ next = &n->right;
+
+ if (next)
+ {
+ /* Check whether our recursion depth is too high. Abort this search,
+ and signal that a rebalance is required to continue. */
+ if (sp->depth > sp->max_depth)
+ {
+ sp->rebalance_p = 1;
+ return n;
+ }
+
+ /* Continue down the tree. */
+ sp->depth ++;
+ n = mfsplay_tree_splay_helper (sp, key, next, node, parent);
+ sp->depth --;
+
+ /* The recursive call will change the place to which NODE
+ points. */
+ if (*node != n || sp->rebalance_p)
+ return n;
+ }
+
+ if (!parent)
+ /* NODE is the root. We are done. */
+ return n;
+
+ /* First, handle the case where there is no grandparent (i.e.,
+ *PARENT is the root of the tree.) */
+ if (!grandparent)
+ {
+ if (n == (*parent)->left)
+ {
+ *node = n->right;
+ n->right = *parent;
+ }
+ else
+ {
+ *node = n->left;
+ n->left = *parent;
+ }
+ *parent = n;
+ return n;
+ }
+
+ /* Next handle the cases where both N and *PARENT are left children,
+ or where both are right children. */
+ if (n == (*parent)->left && *parent == (*grandparent)->left)
+ {
+ mfsplay_tree_node p = *parent;
+
+ (*grandparent)->left = p->right;
+ p->right = *grandparent;
+ p->left = n->right;
+ n->right = p;
+ *grandparent = n;
+ return n;
+ }
+ else if (n == (*parent)->right && *parent == (*grandparent)->right)
+ {
+ mfsplay_tree_node p = *parent;
+
+ (*grandparent)->right = p->left;
+ p->left = *grandparent;
+ p->right = n->left;
+ n->left = p;
+ *grandparent = n;
+ return n;
+ }
+
+ /* Finally, deal with the case where N is a left child, but *PARENT
+ is a right child, or vice versa. */
+ if (n == (*parent)->left)
+ {
+ (*parent)->left = n->right;
+ n->right = *parent;
+ (*grandparent)->right = n->left;
+ n->left = *grandparent;
+ *grandparent = n;
+ return n;
+ }
+ else
+ {
+ (*parent)->right = n->left;
+ n->left = *parent;
+ (*grandparent)->left = n->right;
+ n->right = *grandparent;
+ *grandparent = n;
+ return n;
+ }
+}
+
+
+
+static int
+mfsplay_tree_rebalance_helper1 (mfsplay_tree_node n, void *array_ptr)
+{
+ mfsplay_tree_node **p = array_ptr;
+ *(*p) = n;
+ (*p)++;
+ return 0;
+}
+
+
+static mfsplay_tree_node
+mfsplay_tree_rebalance_helper2 (mfsplay_tree_node * array, unsigned low,
+ unsigned high)
+{
+ unsigned middle = low + (high - low) / 2;
+ mfsplay_tree_node n = array[middle];
+
+ /* Note that since we're producing a balanced binary tree, it is not a problem
+ that this function is recursive. */
+ if (low + 1 <= middle)
+ n->left = mfsplay_tree_rebalance_helper2 (array, low, middle - 1);
+ else
+ n->left = NULL;
+
+ if (middle + 1 <= high)
+ n->right = mfsplay_tree_rebalance_helper2 (array, middle + 1, high);
+ else
+ n->right = NULL;
+
+ return n;
+}
+
+
+/* Rebalance the entire tree. Do this by copying all the node
+ pointers into an array, then cleverly re-linking them. */
+static void
+mfsplay_tree_rebalance (mfsplay_tree sp)
+{
+ mfsplay_tree_node *all_nodes, *all_nodes_1;
+
+ if (sp->num_keys <= 2)
+ return;
+
+ all_nodes = mfsplay_tree_xmalloc (sizeof (mfsplay_tree_node) * sp->num_keys);
+
+ /* Traverse all nodes to copy their addresses into this array. */
+ all_nodes_1 = all_nodes;
+ mfsplay_tree_foreach (sp, mfsplay_tree_rebalance_helper1,
+ (void *) &all_nodes_1);
+
+ /* Relink all the nodes. */
+ sp->root = mfsplay_tree_rebalance_helper2 (all_nodes, 0, sp->num_keys - 1);
+
+ mfsplay_tree_free (all_nodes);
+}
+
+
+/* Splay SP around KEY. */
+static void
+mfsplay_tree_splay (mfsplay_tree sp, mfsplay_tree_key key)
+{
+ if (sp->root == 0)
+ return;
+
+ /* If we just splayed the tree with the same key, do nothing. */
+ if (sp->last_splayed_key_p &&
+ compare_uintptr_t (sp->last_splayed_key, key) == 0)
+ return;
+
+ /* Compute a maximum recursion depth for a splay tree with NUM nodes.
+ The idea is to limit excessive stack usage if we're facing
+ degenerate access patterns. Unfortunately such patterns can occur
+ e.g. during static initialization, where many static objects might
+ be registered in increasing address sequence, or during a case where
+ large tree-like heap data structures are allocated quickly.
+
+ On x86, this corresponds to roughly 200K of stack usage.
+ XXX: For libmudflapth, this could be a function of __mf_opts.thread_stack. */
+ sp->max_depth = 2500;
+ sp->rebalance_p = sp->depth = 0;
+
+ mfsplay_tree_splay_helper (sp, key, &sp->root, NULL, NULL);
+ if (sp->rebalance_p)
+ {
+ mfsplay_tree_rebalance (sp);
+
+ sp->rebalance_p = sp->depth = 0;
+ mfsplay_tree_splay_helper (sp, key, &sp->root, NULL, NULL);
+
+ if (sp->rebalance_p)
+ abort ();
+ }
+
+
+ /* Cache this splay key. */
+ sp->last_splayed_key = key;
+ sp->last_splayed_key_p = 1;
+}
+
+
+
+/* Allocate a new splay tree. */
+static mfsplay_tree
+mfsplay_tree_new ()
+{
+ mfsplay_tree sp = mfsplay_tree_xmalloc (sizeof (struct mfsplay_tree_s));
+ sp->root = NULL;
+ sp->last_splayed_key_p = 0;
+ sp->num_keys = 0;
+
+ return sp;
+}
+
+
+
+/* Insert a new node (associating KEY with DATA) into SP. If a
+ previous node with the indicated KEY exists, its data is replaced
+ with the new value. Returns the new node. */
+static mfsplay_tree_node
+mfsplay_tree_insert (mfsplay_tree sp, mfsplay_tree_key key, mfsplay_tree_value value)
+{
+ int comparison = 0;
+
+ mfsplay_tree_splay (sp, key);
+
+ if (sp->root)
+ comparison = compare_uintptr_t (sp->root->key, key);
+
+ if (sp->root && comparison == 0)
+ {
+ /* If the root of the tree already has the indicated KEY, just
+ replace the value with VALUE. */
+ sp->root->value = value;
+ }
+ else
+ {
+ /* Create a new node, and insert it at the root. */
+ mfsplay_tree_node node;
+
+ node = mfsplay_tree_xmalloc (sizeof (struct mfsplay_tree_node_s));
+ node->key = key;
+ node->value = value;
+ sp->num_keys++;
+ if (!sp->root)
+ node->left = node->right = 0;
+ else if (comparison < 0)
+ {
+ node->left = sp->root;
+ node->right = node->left->right;
+ node->left->right = 0;
+ }
+ else
+ {
+ node->right = sp->root;
+ node->left = node->right->left;
+ node->right->left = 0;
+ }
+
+ sp->root = node;
+ sp->last_splayed_key_p = 0;
+ }
+
+ return sp->root;
+}
+
+/* Remove KEY from SP. It is not an error if it did not exist. */
+
+static void
+mfsplay_tree_remove (mfsplay_tree sp, mfsplay_tree_key key)
+{
+ mfsplay_tree_splay (sp, key);
+ sp->last_splayed_key_p = 0;
+ if (sp->root && compare_uintptr_t (sp->root->key, key) == 0)
+ {
+ mfsplay_tree_node left, right;
+ left = sp->root->left;
+ right = sp->root->right;
+ /* Delete the root node itself. */
+ mfsplay_tree_free (sp->root);
+ sp->num_keys--;
+ /* One of the children is now the root. Doesn't matter much
+ which, so long as we preserve the properties of the tree. */
+ if (left)
+ {
+ sp->root = left;
+ /* If there was a right child as well, hang it off the
+ right-most leaf of the left child. */
+ if (right)
+ {
+ while (left->right)
+ left = left->right;
+ left->right = right;
+ }
+ }
+ else
+ sp->root = right;
+ }
+}
+
+/* Lookup KEY in SP, returning VALUE if present, and NULL
+ otherwise. */
+
+static mfsplay_tree_node
+mfsplay_tree_lookup (mfsplay_tree sp, mfsplay_tree_key key)
+{
+ mfsplay_tree_splay (sp, key);
+ if (sp->root && compare_uintptr_t (sp->root->key, key) == 0)
+ return sp->root;
+ else
+ return 0;
+}
+
+
+/* Return the immediate predecessor KEY, or NULL if there is no
+ predecessor. KEY need not be present in the tree. */
+
+static mfsplay_tree_node
+mfsplay_tree_predecessor (mfsplay_tree sp, mfsplay_tree_key key)
+{
+ int comparison;
+ mfsplay_tree_node node;
+ /* If the tree is empty, there is certainly no predecessor. */
+ if (!sp->root)
+ return NULL;
+ /* Splay the tree around KEY. That will leave either the KEY
+ itself, its predecessor, or its successor at the root. */
+ mfsplay_tree_splay (sp, key);
+ comparison = compare_uintptr_t (sp->root->key, key);
+ /* If the predecessor is at the root, just return it. */
+ if (comparison < 0)
+ return sp->root;
+ /* Otherwise, find the rightmost element of the left subtree. */
+ node = sp->root->left;
+ if (node)
+ while (node->right)
+ node = node->right;
+ return node;
+}
+
+/* Return the immediate successor KEY, or NULL if there is no
+ successor. KEY need not be present in the tree. */
+
+static mfsplay_tree_node
+mfsplay_tree_successor (mfsplay_tree sp, mfsplay_tree_key key)
+{
+ int comparison;
+ mfsplay_tree_node node;
+ /* If the tree is empty, there is certainly no successor. */
+ if (!sp->root)
+ return NULL;
+ /* Splay the tree around KEY. That will leave either the KEY
+ itself, its predecessor, or its successor at the root. */
+ mfsplay_tree_splay (sp, key);
+ comparison = compare_uintptr_t (sp->root->key, key);
+ /* If the successor is at the root, just return it. */
+ if (comparison > 0)
+ return sp->root;
+ /* Otherwise, find the leftmost element of the right subtree. */
+ node = sp->root->right;
+ if (node)
+ while (node->left)
+ node = node->left;
+ return node;
+}
+
+/* Call FN, passing it the DATA, for every node in SP, following an
+ in-order traversal. If FN every returns a non-zero value, the
+ iteration ceases immediately, and the value is returned.
+ Otherwise, this function returns 0.
+
+ This function simulates recursion using dynamically allocated
+ arrays, since it may be called from mfsplay_tree_rebalance(), which
+ in turn means that the tree is already uncomfortably deep for stack
+ space limits. */
+static int
+mfsplay_tree_foreach (mfsplay_tree st, mfsplay_tree_foreach_fn fn, void *data)
+{
+ mfsplay_tree_node *stack1;
+ char *stack2;
+ unsigned sp;
+ int val = 0;
+ enum s { s_left, s_here, s_right, s_up };
+
+ if (st->root == NULL) /* => num_keys == 0 */
+ return 0;
+
+ stack1 = mfsplay_tree_xmalloc (sizeof (mfsplay_tree_node) * st->num_keys);
+ stack2 = mfsplay_tree_xmalloc (sizeof (char) * st->num_keys);
+
+ sp = 0;
+ stack1 [sp] = st->root;
+ stack2 [sp] = s_left;
+
+ while (1)
+ {
+ mfsplay_tree_node n;
+ enum s s;
+
+ n = stack1 [sp];
+ s = stack2 [sp];
+
+ /* Handle each of the four possible states separately. */
+
+ /* 1: We're here to traverse the left subtree (if any). */
+ if (s == s_left)
+ {
+ stack2 [sp] = s_here;
+ if (n->left != NULL)
+ {
+ sp ++;
+ stack1 [sp] = n->left;
+ stack2 [sp] = s_left;
+ }
+ }
+
+ /* 2: We're here to traverse this node. */
+ else if (s == s_here)
+ {
+ stack2 [sp] = s_right;
+ val = (*fn) (n, data);
+ if (val) break;
+ }
+
+ /* 3: We're here to traverse the right subtree (if any). */
+ else if (s == s_right)
+ {
+ stack2 [sp] = s_up;
+ if (n->right != NULL)
+ {
+ sp ++;
+ stack1 [sp] = n->right;
+ stack2 [sp] = s_left;
+ }
+ }
+
+ /* 4: We're here after both subtrees (if any) have been traversed. */
+ else if (s == s_up)
+ {
+ /* Pop the stack. */
+ if (sp == 0) break; /* Popping off the root note: we're finished! */
+ sp --;
+ }
+
+ else
+ abort ();
+ }
+
+ mfsplay_tree_free (stack1);
+ mfsplay_tree_free (stack2);
+ return val;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-05 19:20:47 +0000