*
*/
+#include "private/dbg_mlc.h"
+
/*
* This implements a full, though not well-tuned, representation of the
* backwards points-to graph. This is used to test for non-GC-robust
#ifdef MAKE_BACK_GRAPH
-#define MAX_IN 10 /* Maximum in-degree we handle directly */
+#define MAX_IN 10 /* Maximum in-degree we handle directly */
-#include "private/dbg_mlc.h"
/* #include <unistd.h> */
#if !defined(DBG_HDRS_ALL) || (ALIGNMENT != CPP_WORDSZ/8) /* || !defined(UNIX_LIKE) */
-# error Configuration doesnt support MAKE_BACK_GRAPH
+# error The configuration does not support MAKE_BACK_GRAPH
#endif
-/* We store single back pointers directly in the object's oh_bg_ptr field. */
-/* If there is more than one ptr to an object, we store q | FLAG_MANY, */
-/* where q is a pointer to a back_edges object. */
-/* Every once in a while we use a back_edges object even for a single */
-/* pointer, since we need the other fields in the back_edges structure to */
-/* be present in some fraction of the objects. Otherwise we get serious */
-/* performance issues. */
+/* We store single back pointers directly in the object's oh_bg_ptr field. */
+/* If there is more than one ptr to an object, we store q | FLAG_MANY, */
+/* where q is a pointer to a back_edges object. */
+/* Every once in a while we use a back_edges object even for a single */
+/* pointer, since we need the other fields in the back_edges structure to */
+/* be present in some fraction of the objects. Otherwise we get serious */
+/* performance issues. */
#define FLAG_MANY 2
typedef struct back_edges_struct {
- word n_edges; /* Number of edges, including those in continuation */
- /* structures. */
+ word n_edges; /* Number of edges, including those in continuation */
+ /* structures. */
unsigned short flags;
-# define RETAIN 1 /* Directly points to a reachable object; */
- /* retain for next GC. */
+# define RETAIN 1 /* Directly points to a reachable object; */
+ /* retain for next GC. */
unsigned short height_gc_no;
- /* If height > 0, then the GC_gc_no value when it */
- /* was computed. If it was computed this cycle, then */
- /* it is current. If it was computed during the */
- /* last cycle, then it represents the old height, */
- /* which is only saved for live objects referenced by */
- /* dead ones. This may grow due to refs from newly */
- /* dead objects. */
+ /* If height > 0, then the GC_gc_no value when it */
+ /* was computed. If it was computed this cycle, then */
+ /* it is current. If it was computed during the */
+ /* last cycle, then it represents the old height, */
+ /* which is only saved for live objects referenced by */
+ /* dead ones. This may grow due to refs from newly */
+ /* dead objects. */
signed_word height;
- /* Longest path through unreachable nodes to this node */
- /* that we found using depth first search. */
-
+ /* Longest path through unreachable nodes to this node */
+ /* that we found using depth first search. */
+
# define HEIGHT_UNKNOWN ((signed_word)(-2))
# define HEIGHT_IN_PROGRESS ((signed_word)(-1))
ptr_t edges[MAX_IN];
struct back_edges_struct *cont;
- /* Pointer to continuation structure; we use only the */
- /* edges field in the continuation. */
- /* also used as free list link. */
+ /* Pointer to continuation structure; we use only the */
+ /* edges field in the continuation. */
+ /* also used as free list link. */
} back_edges;
-/* Allocate a new back edge structure. Should be more sophisticated */
-/* if this were production code. */
+/* Allocate a new back edge structure. Should be more sophisticated */
+/* if this were production code. */
#define MAX_BACK_EDGE_STRUCTS 100000
static back_edges *back_edge_space = 0;
STATIC int GC_n_back_edge_structs = 0;
- /* Serves as pointer to never used */
- /* back_edges space. */
+ /* Serves as pointer to never used */
+ /* back_edges space. */
static back_edges *avail_back_edges = 0;
- /* Pointer to free list of deallocated */
- /* back_edges structures. */
+ /* Pointer to free list of deallocated */
+ /* back_edges structures. */
static back_edges * new_back_edges(void)
{
if (0 == back_edge_space) {
back_edge_space = (back_edges *)
- GET_MEM(MAX_BACK_EDGE_STRUCTS*sizeof(back_edges));
+ GET_MEM(MAX_BACK_EDGE_STRUCTS*sizeof(back_edges));
GC_add_to_our_memory((ptr_t)back_edge_space,
- MAX_BACK_EDGE_STRUCTS*sizeof(back_edges));
+ MAX_BACK_EDGE_STRUCTS*sizeof(back_edges));
}
if (0 != avail_back_edges) {
back_edges * result = avail_back_edges;
}
if (GC_n_back_edge_structs >= MAX_BACK_EDGE_STRUCTS - 1) {
ABORT("needed too much space for back edges: adjust "
- "MAX_BACK_EDGE_STRUCTS");
+ "MAX_BACK_EDGE_STRUCTS");
}
return back_edge_space + (GC_n_back_edge_structs++);
}
-/* Deallocate p and its associated continuation structures. */
+/* Deallocate p and its associated continuation structures. */
static void deallocate_back_edges(back_edges *p)
{
back_edges *last = p;
avail_back_edges = p;
}
-/* Table of objects that are currently on the depth-first search */
-/* stack. Only objects with in-degree one are in this table. */
-/* Other objects are identified using HEIGHT_IN_PROGRESS. */
-/* FIXME: This data structure NEEDS IMPROVEMENT. */
+/* Table of objects that are currently on the depth-first search */
+/* stack. Only objects with in-degree one are in this table. */
+/* Other objects are identified using HEIGHT_IN_PROGRESS. */
+/* FIXME: This data structure NEEDS IMPROVEMENT. */
#define INITIAL_IN_PROGRESS 10000
static ptr_t * in_progress_space = 0;
static size_t in_progress_size = 0;
in_progress_size = INITIAL_IN_PROGRESS;
in_progress_space = (ptr_t *)GET_MEM(in_progress_size * sizeof(ptr_t));
GC_add_to_our_memory((ptr_t)in_progress_space,
- in_progress_size * sizeof(ptr_t));
+ in_progress_size * sizeof(ptr_t));
} else {
ptr_t * new_in_progress_space;
in_progress_size *= 2;
new_in_progress_space = (ptr_t *)
- GET_MEM(in_progress_size * sizeof(ptr_t));
+ GET_MEM(in_progress_size * sizeof(ptr_t));
GC_add_to_our_memory((ptr_t)new_in_progress_space,
- in_progress_size * sizeof(ptr_t));
+ in_progress_size * sizeof(ptr_t));
BCOPY(in_progress_space, new_in_progress_space,
- n_in_progress * sizeof(ptr_t));
+ n_in_progress * sizeof(ptr_t));
in_progress_space = new_in_progress_space;
- /* FIXME: This just drops the old space. */
+ /* FIXME: This just drops the old space. */
}
}
if (in_progress_space == 0)
ABORT("MAKE_BACK_GRAPH: Out of in-progress space: "
- "Huge linear data structure?");
+ "Huge linear data structure?");
in_progress_space[n_in_progress++] = p;
}
return FALSE;
}
-static void pop_in_progress(ptr_t p)
+GC_INLINE void pop_in_progress(ptr_t p)
{
--n_in_progress;
GC_ASSERT(in_progress_space[n_in_progress] == p);
}
#define GET_OH_BG_PTR(p) \
- (ptr_t)REVEAL_POINTER(((oh *)(p)) -> oh_bg_ptr)
-#define SET_OH_BG_PTR(p,q) (((oh *)(p)) -> oh_bg_ptr) = HIDE_POINTER(q)
+ (ptr_t)GC_REVEAL_POINTER(((oh *)(p)) -> oh_bg_ptr)
+#define SET_OH_BG_PTR(p,q) (((oh *)(p)) -> oh_bg_ptr = GC_HIDE_POINTER(q))
-/* Execute s once for each predecessor q of p in the points-to graph. */
-/* s should be a bracketed statement. We declare q. */
+/* Execute s once for each predecessor q of p in the points-to graph. */
+/* s should be a bracketed statement. We declare q. */
#define FOR_EACH_PRED(q, p, s) \
{ \
ptr_t q = GET_OH_BG_PTR(p); \
if (!((word)q & FLAG_MANY)) { \
if (q && !((word)q & 1)) s \
- /* !((word)q & 1) checks for a misnterpreted freelist link */ \
+ /* !((word)q & 1) checks for a misnterpreted freelist link */ \
} else { \
back_edges *orig_be_ = (back_edges *)((word)q & ~FLAG_MANY); \
back_edges *be_ = orig_be_; \
word total_; \
word n_edges_ = be_ -> n_edges; \
for (total_ = 0, local_ = 0; total_ < n_edges_; ++local_, ++total_) { \
- if (local_ == MAX_IN) { \
- be_ = be_ -> cont; \
- local_ = 0; \
- } \
- q = be_ -> edges[local_]; s \
+ if (local_ == MAX_IN) { \
+ be_ = be_ -> cont; \
+ local_ = 0; \
+ } \
+ q = be_ -> edges[local_]; s \
} \
} \
}
-/* Ensure that p has a back_edges structure associated with it. */
+/* Ensure that p has a back_edges structure associated with it. */
static void ensure_struct(ptr_t p)
{
ptr_t old_back_ptr = GET_OH_BG_PTR(p);
}
}
-/* Add the (forward) edge from p to q to the backward graph. Both p */
-/* q are pointers to the object base, i.e. pointers to an oh. */
-static void add_edge(ptr_t p, ptr_t q)
+/* Add the (forward) edge from p to q to the backward graph. Both p */
+/* q are pointers to the object base, i.e. pointers to an oh. */
+static void add_edge(ptr_t p, ptr_t q)
{
ptr_t old_back_ptr = GET_OH_BG_PTR(q);
back_edges * be, *be_cont;
word i;
static unsigned random_number = 13;
# define GOT_LUCKY_NUMBER (((++random_number) & 0x7f) == 0)
- /* A not very random number we use to occasionally allocate a */
- /* back_edges structure even for a single backward edge. This */
- /* prevents us from repeatedly tracing back through very long */
- /* chains, since we will have some place to store height and */
- /* in_progress flags along the way. */
+ /* A not very random number we use to occasionally allocate a */
+ /* back_edges structure even for a single backward edge. This */
+ /* prevents us from repeatedly tracing back through very long */
+ /* chains, since we will have some place to store height and */
+ /* in_progress flags along the way. */
GC_ASSERT(p == GC_base(p) && q == GC_base(q));
if (!GC_HAS_DEBUG_INFO(q) || !GC_HAS_DEBUG_INFO(p)) {
- /* This is really a misinterpreted free list link, since we saw */
- /* a pointer to a free list. Dont overwrite it! */
+ /* This is really a misinterpreted free list link, since we saw */
+ /* a pointer to a free list. Don't overwrite it! */
return;
}
if (0 == old_back_ptr) {
- SET_OH_BG_PTR(q, p);
- if (GOT_LUCKY_NUMBER) ensure_struct(q);
- return;
+ SET_OH_BG_PTR(q, p);
+ if (GOT_LUCKY_NUMBER) ensure_struct(q);
+ return;
}
/* Check whether it was already in the list of predecessors. */
FOR_EACH_PRED(pred, q, { if (p == pred) return; });
ensure_struct(q);
old_back_ptr = GET_OH_BG_PTR(q);
be = (back_edges *)((word)old_back_ptr & ~FLAG_MANY);
- for (i = be -> n_edges, be_cont = be; i > MAX_IN;
- be_cont = be_cont -> cont, i -= MAX_IN) {}
+ for (i = be -> n_edges, be_cont = be; i > MAX_IN; i -= MAX_IN)
+ be_cont = be_cont -> cont;
if (i == MAX_IN) {
- be_cont -> cont = new_back_edges();
- be_cont = be_cont -> cont;
- i = 0;
+ be_cont -> cont = new_back_edges();
+ be_cont = be_cont -> cont;
+ i = 0;
}
be_cont -> edges[i] = p;
be -> n_edges++;
if (be -> n_edges == 100) {
# if 0
- if (GC_print_stats) {
- GC_err_printf("The following object has in-degree >= 100:\n");
- GC_print_heap_obj(q);
- }
-# endif
+ if (GC_print_stats) {
+ GC_err_printf("The following object has in-degree >= 100:\n");
+ GC_print_heap_obj(q);
+ }
+# endif
}
}
} while (i + (int)sz <= BYTES_TO_WORDS(HBLKSIZE));
}
-void GC_apply_to_each_object(per_object_func f)
+GC_INLINE void GC_apply_to_each_object(per_object_func f)
{
GC_apply_to_all_blocks(per_object_helper, (word)f);
}
if ((word)old_back_ptr & FLAG_MANY) {
back_edges *be = (back_edges *)((word)old_back_ptr & ~FLAG_MANY);
if (!(be -> flags & RETAIN)) {
- deallocate_back_edges(be);
- SET_OH_BG_PTR(p, 0);
+ deallocate_back_edges(be);
+ SET_OH_BG_PTR(p, 0);
} else {
- GC_ASSERT(GC_is_marked(p));
+ GC_ASSERT(GC_is_marked(p));
- /* Back edges may point to objects that will not be retained. */
- /* Delete them for now, but remember the height. */
- /* Some will be added back at next GC. */
- be -> n_edges = 0;
- if (0 != be -> cont) {
- deallocate_back_edges(be -> cont);
- be -> cont = 0;
- }
+ /* Back edges may point to objects that will not be retained. */
+ /* Delete them for now, but remember the height. */
+ /* Some will be added back at next GC. */
+ be -> n_edges = 0;
+ if (0 != be -> cont) {
+ deallocate_back_edges(be -> cont);
+ be -> cont = 0;
+ }
- GC_ASSERT(GC_is_marked(p));
+ GC_ASSERT(GC_is_marked(p));
- /* We only retain things for one GC cycle at a time. */
- be -> flags &= ~RETAIN;
+ /* We only retain things for one GC cycle at a time. */
+ be -> flags &= ~RETAIN;
}
} else /* Simple back pointer */ {
/* Clear to avoid dangling pointer. */
{
word *currentp = (word *)(p + sizeof(oh));
- /* For now, fix up non-length descriptors conservatively. */
+ /* For now, fix up non-length descriptors conservatively. */
if((gc_descr & GC_DS_TAGS) != GC_DS_LENGTH) {
gc_descr = n_bytes;
}
while (currentp < (word *)(p + gc_descr)) {
word current = *currentp++;
FIXUP_POINTER(current);
- if (current >= (word)GC_least_plausible_heap_addr &&
- current <= (word)GC_greatest_plausible_heap_addr) {
+ if (current >= (word)GC_least_plausible_heap_addr &&
+ current <= (word)GC_greatest_plausible_heap_addr) {
ptr_t target = GC_base((void *)current);
if (0 != target) {
- add_edge(p, target);
+ add_edge(p, target);
}
}
}
}
-/* Rebuild the representation of the backward reachability graph. */
-/* Does not examine mark bits. Can be called before GC. */
-void GC_build_back_graph(void)
+/* Rebuild the representation of the backward reachability graph. */
+/* Does not examine mark bits. Can be called before GC. */
+GC_INNER void GC_build_back_graph(void)
{
GC_apply_to_each_object(add_back_edges);
}
-/* Return an approximation to the length of the longest simple path */
-/* through unreachable objects to p. We refer to this as the height */
-/* of p. */
+/* Return an approximation to the length of the longest simple path */
+/* through unreachable objects to p. We refer to this as the height */
+/* of p. */
static word backwards_height(ptr_t p)
{
word result;
if (0 == back_ptr) return 1;
if (!((word)back_ptr & FLAG_MANY)) {
- if (is_in_progress(p)) return 0; /* DFS back edge, i.e. we followed */
- /* an edge to an object already */
- /* on our stack: ignore */
+ if (is_in_progress(p)) return 0; /* DFS back edge, i.e. we followed */
+ /* an edge to an object already */
+ /* on our stack: ignore */
push_in_progress(p);
result = backwards_height(back_ptr)+1;
pop_in_progress(p);
word this_height;
if (GC_is_marked(q) && !(FLAG_MANY & (word)GET_OH_BG_PTR(p))) {
if (GC_print_stats)
- GC_log_printf("Found bogus pointer from %p to %p\n", q, p);
- /* Reachable object "points to" unreachable one. */
- /* Could be caused by our lax treatment of GC descriptors. */
+ GC_log_printf("Found bogus pointer from %p to %p\n", q, p);
+ /* Reachable object "points to" unreachable one. */
+ /* Could be caused by our lax treatment of GC descriptors. */
this_height = 1;
} else {
this_height = backwards_height(q);
return result;
}
-STATIC word GC_max_height;
-STATIC ptr_t GC_deepest_obj;
+STATIC word GC_max_height = 0;
+STATIC ptr_t GC_deepest_obj = NULL;
-/* Compute the maximum height of every unreachable predecessor p of a */
-/* reachable object. Arrange to save the heights of all such objects p */
-/* so that they can be used in calculating the height of objects in the */
-/* next GC. */
-/* Set GC_max_height to be the maximum height we encounter, and */
-/* GC_deepest_obj to be the corresponding object. */
+/* Compute the maximum height of every unreachable predecessor p of a */
+/* reachable object. Arrange to save the heights of all such objects p */
+/* so that they can be used in calculating the height of objects in the */
+/* next GC. */
+/* Set GC_max_height to be the maximum height we encounter, and */
+/* GC_deepest_obj to be the corresponding object. */
/*ARGSUSED*/
static void update_max_height(ptr_t p, size_t n_bytes, word gc_descr)
{
ptr_t back_ptr;
back_edges *be = 0;
- /* If we remembered a height last time, use it as a minimum. */
- /* It may have increased due to newly unreachable chains pointing */
- /* to p, but it can't have decreased. */
+ /* If we remembered a height last time, use it as a minimum. */
+ /* It may have increased due to newly unreachable chains pointing */
+ /* to p, but it can't have decreased. */
back_ptr = GET_OH_BG_PTR(p);
if (0 != back_ptr && ((word)back_ptr & FLAG_MANY)) {
be = (back_edges *)((word)back_ptr & ~FLAG_MANY);
word q_height;
q_height = backwards_height(q);
- if (q_height > p_height) {
- p_height = q_height;
- p_deepest_obj = q;
- }
+ if (q_height > p_height) {
+ p_height = q_height;
+ p_deepest_obj = q;
+ }
}
});
if (p_height > 0) {
/* Remember the height for next time. */
- if (be == 0) {
- ensure_struct(p);
- back_ptr = GET_OH_BG_PTR(p);
- be = (back_edges *)((word)back_ptr & ~FLAG_MANY);
- }
- be -> flags |= RETAIN;
- be -> height = p_height;
- be -> height_gc_no = (unsigned short)GC_gc_no;
+ if (be == 0) {
+ ensure_struct(p);
+ back_ptr = GET_OH_BG_PTR(p);
+ be = (back_edges *)((word)back_ptr & ~FLAG_MANY);
+ }
+ be -> flags |= RETAIN;
+ be -> height = p_height;
+ be -> height_gc_no = (unsigned short)GC_gc_no;
}
if (p_height > GC_max_height) {
- GC_max_height = p_height;
- GC_deepest_obj = p_deepest_obj;
+ GC_max_height = p_height;
+ GC_deepest_obj = p_deepest_obj;
}
}
}
STATIC word GC_max_max_height = 0;
-void GC_traverse_back_graph(void)
+GC_INNER void GC_traverse_back_graph(void)
{
GC_max_height = 0;
GC_apply_to_each_object(update_max_height);
void GC_print_back_graph_stats(void)
{
GC_printf("Maximum backwards height of reachable objects at GC %lu is %ld\n",
- (unsigned long) GC_gc_no, (unsigned long)GC_max_height);
+ (unsigned long) GC_gc_no, (unsigned long)GC_max_height);
if (GC_max_height > GC_max_max_height) {
GC_max_max_height = GC_max_height;
GC_printf("The following unreachable object is last in a longest chain "
- "of unreachable objects:\n");
+ "of unreachable objects:\n");
GC_print_heap_obj(GC_deepest_obj);
}
if (GC_print_stats) {
GC_log_printf("Needed max total of %d back-edge structs\n",
- GC_n_back_edge_structs);
+ GC_n_back_edge_structs);
}
GC_apply_to_each_object(reset_back_edge);
GC_deepest_obj = 0;
}
-#else /* !MAKE_BACK_GRAPH */
-
-extern int GC_quiet;
- /* ANSI C doesn't allow translation units to be empty. */
-
-#endif /* !MAKE_BACK_GRAPH */
+#endif /* MAKE_BACK_GRAPH */
projects / cacao.git / blobdiff