119 lines
4.6 KiB
Diff
119 lines
4.6 KiB
Diff
From 33535060b4898c7883c3d98c4591bfc964541830 Mon Sep 17 00:00:00 2001
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From: Petter Urkedal <paurkedal@gmail.com>
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Date: Sun, 25 May 2014 15:57:03 +0200
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Subject: [PATCH 1/3] Fix GC_finalized_malloc failure on disclaim_test (revert
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part of commit 63fd11d)
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The finalizer closure is placed in the first word in order to use the
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lower bits to distinguish live objects from objects on the free list.
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The downside of this is that we need one-word offset interior pointers,
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and that GC_base does not return the start of the user region.
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* fnlz_mlc.c (GC_finalized_disclaim): Move finalizer closure for
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finalized object kinds back to the start of objects.
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* fnlz_mlc.c (GC_init_finalized_malloc): Call
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GC_register_displacement_inner() as GC_finalized_malloc returns
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displaced pointer.
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* fnlz_mlc.c (GC_core_finalized_malloc, GC_finalized_malloc): Store
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fclos in first word of created object (instead of the last word);
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return pointer to object displaced by 1 word.
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---
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diff --git a/fnlz_mlc.c b/fnlz_mlc.c
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old mode 100755
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new mode 100644
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index 0dad28a..b8478d2
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--- a/fnlz_mlc.c
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+++ b/fnlz_mlc.c
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@@ -28,13 +28,10 @@ STATIC int GC_finalized_kind = 0;
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STATIC int GC_CALLBACK GC_finalized_disclaim(void *obj)
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{
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- void **fc_addr;
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- const struct GC_finalizer_closure *fc;
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+ word fc_word = *(word *)obj;
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- fc_addr = &((void **)obj)[GC_size(obj) / sizeof(void *) - 1];
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- fc = *fc_addr;
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- if (fc != NULL) {
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- /* [1] The disclaim function may be passed fragments from the */
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+ if ((fc_word & 1) != 0) {
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+ /* The disclaim function may be passed fragments from the */
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/* free-list, on which it should not run finalization. */
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/* To recognize this case, we use the fact that the first word */
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/* on such fragments are always even (a link to the next */
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@@ -42,8 +39,8 @@ STATIC int GC_CALLBACK GC_finalized_disclaim(void *obj)
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/* which does not use the first word for storing finalization */
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/* info, GC_reclaim_with_finalization must be extended to clear */
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/* fragments so that the assumption holds for the selected word. */
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- (*fc->proc)(obj, fc->cd);
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- *fc_addr = NULL;
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+ const struct GC_finalizer_closure *fc = (void *)(fc_word & ~(word)1);
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+ (*fc->proc)((word *)obj + 1, fc->cd);
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}
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return 0;
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}
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@@ -62,6 +59,13 @@ GC_API void GC_CALL GC_init_finalized_malloc(void)
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}
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done_init = TRUE;
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+ /* The finalizer closure is placed in the first word in order to */
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+ /* use the lower bits to distinguish live objects from objects on */
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+ /* the free list. The downside of this is that we need one-word */
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+ /* offset interior pointers, and that GC_base does not return the */
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+ /* start of the user region. */
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+ GC_register_displacement_inner(sizeof(word));
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+
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GC_finalized_objfreelist = (ptr_t *)GC_new_free_list_inner();
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GC_finalized_kind = GC_new_kind_inner((void **)GC_finalized_objfreelist,
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GC_DS_LENGTH, TRUE, TRUE);
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@@ -90,7 +94,7 @@ GC_API void GC_CALL GC_register_disclaim_proc(int kind, GC_disclaim_proc proc,
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word lg;
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DCL_LOCK_STATE;
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- lb += sizeof(void *);
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+ lb += sizeof(word);
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GC_ASSERT(done_init);
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if (SMALL_OBJ(lb)) {
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GC_DBG_COLLECT_AT_MALLOC(lb);
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@@ -112,7 +116,6 @@ GC_API void GC_CALL GC_register_disclaim_proc(int kind, GC_disclaim_proc proc,
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UNLOCK();
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}
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GC_ASSERT(lg > 0);
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- ((const void **)op)[GRANULES_TO_WORDS(lg) - 1] = fclos;
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} else {
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size_t op_sz;
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@@ -121,16 +124,16 @@ GC_API void GC_CALL GC_register_disclaim_proc(int kind, GC_disclaim_proc proc,
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return NULL;
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op_sz = GC_size(op);
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GC_ASSERT(op_sz >= lb);
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- ((const void **)op)[op_sz / sizeof(void *) - 1] = fclos;
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}
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- return GC_clear_stack(op);
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+ *(word *)op = (word)fclos | 1;
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+ return GC_clear_stack((word *)op + 1);
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}
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#ifdef THREAD_LOCAL_ALLOC
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GC_API void * GC_CALL GC_finalized_malloc(size_t client_lb,
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const struct GC_finalizer_closure *fclos)
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{
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- size_t lb = client_lb + sizeof(void *);
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+ size_t lb = client_lb + sizeof(word);
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size_t lg = ROUNDED_UP_GRANULES(lb);
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GC_tlfs tsd;
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void *result;
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@@ -163,9 +166,9 @@ GC_API void GC_CALL GC_register_disclaim_proc(int kind, GC_disclaim_proc proc,
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result = (void *)my_entry;
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*my_fl = next;
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obj_link(result) = 0;
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- ((const void **)result)[GRANULES_TO_WORDS(lg) - 1] = fclos;
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+ *(word *)result = (word)fclos | 1;
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PREFETCH_FOR_WRITE(next);
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- return result;
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+ return (word *)result + 1;
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}
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#endif /* THREAD_LOCAL_ALLOC */
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