From: Trevor Saunders <[email protected]>
Hi,
This implements finalizers by keeping a list of registered finalizers
and after every mark but before sweeping check to see if any of them are
for unmarked blocks.
bootstrapped + regtested on x86_64-unknown-linux-gnu, ok?
Trev
gcc/ChangeLog:
* ggc-common.c (ggc_internal_cleared_alloc): Adjust.
* ggc-none.c (ggc_internal_alloc): Assert if a finalizer is passed.
(ggc_internal_cleared_alloc): Likewise.
* ggc-page.c (finalizer): New class.
(globals::finalizer_lists): New member.
(ggc_internal_alloc): Record the finalizer if any for the block being
allocated.
(ggc_handle_finalizers): New function.
(ggc_collect): Call ggc_handle_finalizers.
* ggc.h (ggc_internal_alloc):Add arguments to allow installing a
finalizer.
(ggc_internal_cleared_alloc): Likewise.
(finalize): New function.
(need_finalization_p): Likewise.
(ggc_alloc): Install the type's destructor as the finalizer if it
might do something.
(ggc_cleared_alloc): Likewise.
(ggc_vec_alloc): Likewise.
(ggc_cleared_vec_alloc): Likewise.
---
gcc/ggc-common.c | 5 +++--
gcc/ggc-none.c | 8 ++++++--
gcc/ggc-page.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++-
gcc/ggc.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++------
4 files changed, 104 insertions(+), 11 deletions(-)
diff --git a/gcc/ggc-common.c b/gcc/ggc-common.c
index e89cc64..b11a10c 100644
--- a/gcc/ggc-common.c
+++ b/gcc/ggc-common.c
@@ -174,9 +174,10 @@ ggc_mark_roots (void)
/* Allocate a block of memory, then clear it. */
void *
-ggc_internal_cleared_alloc (size_t size MEM_STAT_DECL)
+ggc_internal_cleared_alloc (size_t size, void (*f)(void *), size_t s, size_t n
+ MEM_STAT_DECL)
{
- void *buf = ggc_internal_alloc (size PASS_MEM_STAT);
+ void *buf = ggc_internal_alloc (size, f, s, n PASS_MEM_STAT);
memset (buf, 0, size);
return buf;
}
diff --git a/gcc/ggc-none.c b/gcc/ggc-none.c
index aad89bf..97d3566 100644
--- a/gcc/ggc-none.c
+++ b/gcc/ggc-none.c
@@ -41,14 +41,18 @@ ggc_round_alloc_size (size_t requested_size)
}
void *
-ggc_internal_alloc (size_t size MEM_STAT_DECL)
+ggc_internal_alloc (size_t size, void (*f)(void *), size_t, size_t
+ MEM_STAT_DECL)
{
+ gcc_assert (!f); // ggc-none doesn't support finalizers
return xmalloc (size);
}
void *
-ggc_internal_cleared_alloc (size_t size MEM_STAT_DECL)
+ggc_internal_cleared_alloc (size_t size, void (*f)(void *), size_t, size_t
+ MEM_STAT_DECL)
{
+ gcc_assert (!f); // ggc-none doesn't support finalizers
return xcalloc (size, 1);
}
diff --git a/gcc/ggc-page.c b/gcc/ggc-page.c
index ae5e88a..208b526 100644
--- a/gcc/ggc-page.c
+++ b/gcc/ggc-page.c
@@ -332,6 +332,27 @@ typedef struct page_table_chain
#endif
+class finalizer
+{
+public:
+ finalizer (uintptr_t addr, void (*f)(void *), size_t s, size_t n) :
+ m_addr (addr), m_function (f), m_object_size (s), m_n_objects (n) {}
+
+ void call () const
+ {
+ for (size_t i = 0; i < m_n_objects; i++)
+ m_function (reinterpret_cast<void *> (m_addr + (i * m_object_size)));
+ }
+
+ uintptr_t addr () const { return m_addr; }
+
+private:
+ uintptr_t m_addr;
+ void (*m_function)(void *);
+ size_t m_object_size;
+ size_t m_n_objects;
+};
+
#ifdef ENABLE_GC_ALWAYS_COLLECT
/* List of free objects to be verified as actually free on the
next collection. */
@@ -425,6 +446,9 @@ static struct globals
better runtime data access pattern. */
unsigned long **save_in_use;
+ /* finalizer_lists[i] is the list of finalizers for blocks of order i. */
+ vec<finalizer> finalizer_lists[NUM_ORDERS];
+
#ifdef ENABLE_GC_ALWAYS_COLLECT
/* List of free objects to be verified as actually free on the
next collection. */
@@ -1202,7 +1226,8 @@ ggc_round_alloc_size (size_t requested_size)
/* Allocate a chunk of memory of SIZE bytes. Its contents are undefined. */
void *
-ggc_internal_alloc (size_t size MEM_STAT_DECL)
+ggc_internal_alloc (size_t size, void (*f)(void *), size_t s, size_t n
+ MEM_STAT_DECL)
{
size_t order, word, bit, object_offset, object_size;
struct page_entry *entry;
@@ -1345,6 +1370,10 @@ ggc_internal_alloc (size_t size MEM_STAT_DECL)
/* For timevar statistics. */
timevar_ggc_mem_total += object_size;
+ if (f)
+ G.finalizer_lists[order]
+ .safe_push (finalizer (reinterpret_cast<uintptr_t> (result), f, s, n));
+
if (GATHER_STATISTICS)
{
size_t overhead = object_size - size;
@@ -1811,6 +1840,24 @@ clear_marks (void)
}
}
+static void
+ggc_handle_finalizers ()
+{
+ for (unsigned int order = 2; order < NUM_ORDERS; order++)
+ {
+ unsigned int length = G.finalizer_lists[order].length ();
+ for (unsigned int i = length - 1; i < length; i--)
+ {
+ finalizer &f = G.finalizer_lists[order][i];
+ if (!ggc_marked_p (reinterpret_cast<void *> (f.addr ())))
+ {
+ f.call ();
+ G.finalizer_lists[order].ordered_remove (i);
+ }
+ }
+ }
+}
+
/* Free all empty pages. Partially empty pages need no attention
because the `mark' bit doubles as an `unused' bit. */
@@ -2075,6 +2122,7 @@ ggc_collect (void)
clear_marks ();
ggc_mark_roots ();
+ ggc_handle_finalizers ();
if (GATHER_STATISTICS)
ggc_prune_overhead_list ();
diff --git a/gcc/ggc.h b/gcc/ggc.h
index 50fb199..4c59597 100644
--- a/gcc/ggc.h
+++ b/gcc/ggc.h
@@ -136,13 +136,16 @@ extern void gt_pch_save (FILE *f);
/* Allocation. */
/* The internal primitive. */
-extern void *ggc_internal_alloc (size_t CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
+extern void *ggc_internal_alloc (size_t, void (*)(void *) = NULL, size_t = 0,
+ size_t = 1 CXX_MEM_STAT_INFO)
+ ATTRIBUTE_MALLOC;
extern size_t ggc_round_alloc_size (size_t requested_size);
/* Allocates cleared memory. */
-extern void *ggc_internal_cleared_alloc (size_t CXX_MEM_STAT_INFO)
- ATTRIBUTE_MALLOC;
+extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *) = NULL,
+ size_t = 0, size_t = 1
+ CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
/* Resize a block. */
extern void *ggc_realloc (void *, size_t CXX_MEM_STAT_INFO);
@@ -157,24 +160,55 @@ extern void dump_ggc_loc_statistics (bool);
((T *) ggc_realloc ((P), (N) * sizeof (T) MEM_STAT_INFO))
template<typename T>
+void
+finalize (void *p)
+{
+ static_cast<T *> (p)->~T ();
+}
+
+template<typename T>
+static inline bool
+need_finalization_p ()
+{
+#if GCC_VERSION >= 4003
+ return !__has_trivial_destructor (T);
+#else
+ return true;
+#endif
+}
+
+template<typename T>
static inline T *
ggc_alloc (ALONE_CXX_MEM_STAT_INFO)
{
- return static_cast<T *> (ggc_internal_alloc (sizeof (T) PASS_MEM_STAT));
+ if (need_finalization_p<T> ())
+ return static_cast<T *> (ggc_internal_alloc (sizeof (T), finalize<T>
+ PASS_MEM_STAT));
+ else
+ return static_cast<T *> (ggc_internal_alloc (sizeof (T) PASS_MEM_STAT));
}
template<typename T>
static inline T *
ggc_cleared_alloc (ALONE_CXX_MEM_STAT_INFO)
{
- return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T)
- PASS_MEM_STAT));
+ if (need_finalization_p<T> ())
+ return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T),
+ finalize<T>
+ PASS_MEM_STAT));
+ else
+ return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T)
+ PASS_MEM_STAT));
}
template<typename T>
static inline T *
ggc_vec_alloc (size_t c CXX_MEM_STAT_INFO)
{
+ if (need_finalization_p<T> ())
+ return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), finalize<T>,
+ sizeof (T), c PASS_MEM_STAT));
+ else
return static_cast<T *> (ggc_internal_alloc (c * sizeof (T)
PASS_MEM_STAT));
}
@@ -183,6 +217,12 @@ template<typename T>
static inline T *
ggc_cleared_vec_alloc (size_t c CXX_MEM_STAT_INFO)
{
+ if (need_finalization_p<T> ())
+ return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T),
+ finalize<T>,
+ sizeof (T), c
+ PASS_MEM_STAT));
+ else
return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T)
PASS_MEM_STAT));
}
--
2.0.0.rc0
