wingo pushed a commit to branch wip-whippet
in repository guile.
commit 1493bf6398f53db468c54dd527b92ed62376a388
Author: Andy Wingo <wi...@igalia.com>
AuthorDate: Tue Oct 1 15:44:55 2024 +0200
Add gc_object_is_old_generation
Will be useful for write barriers.
---
api/bdw-attrs.h | 7 +++++++
api/gc-api.h | 32 +++++++++++++++++++++++++++++++-
api/gc-attrs.h | 10 ++++++++++
api/mmc-attrs.h | 13 +++++++++++++
api/pcc-attrs.h | 7 +++++++
api/semi-attrs.h | 7 +++++++
src/bdw.c | 5 +++++
src/large-object-space.h | 4 ++--
src/mmc.c | 19 ++++++++++++++++++-
src/nofl-space.h | 9 +++++++++
src/pcc.c | 5 +++++
src/semi.c | 5 +++++
12 files changed, 119 insertions(+), 4 deletions(-)
diff --git a/api/bdw-attrs.h b/api/bdw-attrs.h
index 51b4e72f1..05f7e4cb7 100644
--- a/api/bdw-attrs.h
+++ b/api/bdw-attrs.h
@@ -40,6 +40,13 @@ static inline int gc_allocator_needs_clear(void) {
return 0;
}
+static inline enum gc_old_generation_check_kind
gc_old_generation_check_kind(size_t) {
+ return GC_OLD_GENERATION_CHECK_NONE;
+}
+static inline uint8_t gc_old_generation_check_alloc_table_bit_pattern(void) {
+ GC_CRASH();
+}
+
static inline enum gc_write_barrier_kind gc_write_barrier_kind(size_t) {
return GC_WRITE_BARRIER_NONE;
}
diff --git a/api/gc-api.h b/api/gc-api.h
index cb1e4e819..8f5565428 100644
--- a/api/gc-api.h
+++ b/api/gc-api.h
@@ -179,6 +179,33 @@ static inline void* gc_allocate(struct gc_mutator *mut,
size_t size) {
// FIXME: remove :P
GC_API_ void* gc_allocate_pointerless(struct gc_mutator *mut, size_t bytes);
+GC_API_ int gc_object_is_old_generation_slow(struct gc_mutator *mut,
+ struct gc_ref obj)
GC_NEVER_INLINE;
+
+static inline int gc_object_is_old_generation(struct gc_mutator *mut,
+ struct gc_ref obj,
+ size_t obj_size)
GC_ALWAYS_INLINE;
+static inline int gc_object_is_old_generation(struct gc_mutator *mut,
+ struct gc_ref obj,
+ size_t obj_size) {
+ switch (gc_old_generation_check_kind(obj_size)) {
+ case GC_OLD_GENERATION_CHECK_ALLOC_TABLE: {
+ size_t alignment = gc_allocator_alloc_table_alignment();
+ GC_ASSERT(alignment);
+ uintptr_t addr = gc_ref_value(obj);
+ uintptr_t base = addr & ~(alignment - 1);
+ size_t granule_size = gc_allocator_small_granule_size();
+ uintptr_t granule = (addr & (alignment - 1)) / granule_size;
+ uint8_t *byte = (uint8_t*)(base + granule);
+ return (*byte) & gc_old_generation_check_alloc_table_bit_pattern();
+ }
+ case GC_OLD_GENERATION_CHECK_SLOW:
+ return gc_object_is_old_generation_slow(mut, obj);
+ default:
+ GC_CRASH();
+ }
+}
+
GC_API_ void gc_write_barrier_slow(struct gc_mutator *mut, struct gc_ref obj,
size_t obj_size, struct gc_edge edge,
struct gc_ref new_val) GC_NEVER_INLINE;
@@ -202,11 +229,14 @@ static inline void gc_write_barrier(struct gc_mutator
*mut, struct gc_ref obj,
return;
}
case GC_WRITE_BARRIER_FIELD: {
+ if (!gc_object_is_old_generation(mut, obj, obj_size))
+ return;
+
size_t field_table_alignment = gc_write_barrier_field_table_alignment();
size_t fields_per_byte = gc_write_barrier_field_fields_per_byte();
uint8_t first_bit_pattern = gc_write_barrier_field_first_bit_pattern();
- uintptr_t addr = (uintptr_t) gc_edge_loc(edge);
+ uintptr_t addr = gc_ref_value(obj);
uintptr_t base = addr & ~(field_table_alignment - 1);
uintptr_t field = (addr & (field_table_alignment - 1)) / sizeof(uintptr_t);
uintptr_t log_byte = field / fields_per_byte;
diff --git a/api/gc-attrs.h b/api/gc-attrs.h
index 39faceae2..389cb536e 100644
--- a/api/gc-attrs.h
+++ b/api/gc-attrs.h
@@ -27,6 +27,16 @@ static inline uint8_t
gc_allocator_alloc_table_end_pattern(void) GC_ALWAYS_INLIN
static inline int gc_allocator_needs_clear(void) GC_ALWAYS_INLINE;
+enum gc_old_generation_check_kind {
+ GC_OLD_GENERATION_CHECK_NONE,
+ GC_OLD_GENERATION_CHECK_ALLOC_TABLE,
+ GC_OLD_GENERATION_CHECK_SLOW
+};
+
+static inline enum gc_old_generation_check_kind
gc_old_generation_check_kind(size_t obj_size) GC_ALWAYS_INLINE;
+
+static uint8_t gc_old_generation_check_alloc_table_bit_pattern(void)
GC_ALWAYS_INLINE;
+
enum gc_write_barrier_kind {
GC_WRITE_BARRIER_NONE,
GC_WRITE_BARRIER_CARD,
diff --git a/api/mmc-attrs.h b/api/mmc-attrs.h
index 6da4b2a68..f527c127b 100644
--- a/api/mmc-attrs.h
+++ b/api/mmc-attrs.h
@@ -40,6 +40,19 @@ static inline int gc_allocator_needs_clear(void) {
return 0;
}
+static inline enum gc_old_generation_check_kind
gc_old_generation_check_kind(size_t obj_size) {
+ if (GC_GENERATIONAL) {
+ if (obj_size <= gc_allocator_large_threshold())
+ return GC_OLD_GENERATION_CHECK_ALLOC_TABLE;
+ return GC_OLD_GENERATION_CHECK_SLOW;
+ }
+ return GC_OLD_GENERATION_CHECK_NONE;
+}
+static inline uint8_t gc_old_generation_check_alloc_table_bit_pattern(void) {
+ // The three mark bits.
+ return 2 + 4 + 8;
+}
+
static inline enum gc_write_barrier_kind gc_write_barrier_kind(size_t
obj_size) {
if (GC_GENERATIONAL) {
if (obj_size <= gc_allocator_large_threshold())
diff --git a/api/pcc-attrs.h b/api/pcc-attrs.h
index 5dd38c42f..c86d79471 100644
--- a/api/pcc-attrs.h
+++ b/api/pcc-attrs.h
@@ -43,6 +43,13 @@ static inline int gc_allocator_needs_clear(void) {
return 0;
}
+static inline enum gc_old_generation_check_kind
gc_old_generation_check_kind(size_t) {
+ return GC_OLD_GENERATION_CHECK_NONE;
+}
+static inline uint8_t gc_old_generation_check_alloc_table_bit_pattern(void) {
+ GC_CRASH();
+}
+
static inline enum gc_write_barrier_kind gc_write_barrier_kind(size_t
obj_size) {
return GC_WRITE_BARRIER_NONE;
}
diff --git a/api/semi-attrs.h b/api/semi-attrs.h
index 94e2dc814..997b031ee 100644
--- a/api/semi-attrs.h
+++ b/api/semi-attrs.h
@@ -42,6 +42,13 @@ static inline uint8_t
gc_allocator_alloc_table_end_pattern(void) {
GC_CRASH();
}
+static inline enum gc_old_generation_check_kind
gc_old_generation_check_kind(size_t) {
+ return GC_OLD_GENERATION_CHECK_NONE;
+}
+static inline uint8_t gc_old_generation_check_alloc_table_bit_pattern(void) {
+ GC_CRASH();
+}
+
static inline enum gc_write_barrier_kind gc_write_barrier_kind(size_t) {
return GC_WRITE_BARRIER_NONE;
}
diff --git a/src/bdw.c b/src/bdw.c
index d4cbe4c41..d1478d805 100644
--- a/src/bdw.c
+++ b/src/bdw.c
@@ -149,6 +149,11 @@ void gc_collect(struct gc_mutator *mut,
}
}
+int gc_object_is_old_generation_slow(struct gc_mutator *mut,
+ struct gc_ref obj) {
+ return 0;
+}
+
void gc_write_barrier_slow(struct gc_mutator *mut, struct gc_ref obj,
size_t obj_size, struct gc_edge edge,
struct gc_ref new_val) {
diff --git a/src/large-object-space.h b/src/large-object-space.h
index 358826b36..323c3f2f8 100644
--- a/src/large-object-space.h
+++ b/src/large-object-space.h
@@ -176,8 +176,8 @@ static int large_object_space_is_copied(struct
large_object_space *space,
return copied;
}
-static int large_object_space_is_old(struct large_object_space *space,
- struct gc_ref ref) {
+static int large_object_space_is_survivor(struct large_object_space *space,
+ struct gc_ref ref) {
GC_ASSERT(large_object_space_contains(space, ref));
int old = 0;
uintptr_t addr = gc_ref_value(ref);
diff --git a/src/mmc.c b/src/mmc.c
index e14346bec..ce1571118 100644
--- a/src/mmc.c
+++ b/src/mmc.c
@@ -879,6 +879,23 @@ gc_pin_object(struct gc_mutator *mut, struct gc_ref ref) {
// Otherwise if it's a large or external object, it won't move.
}
+int gc_object_is_old_generation_slow(struct gc_mutator *mut,
+ struct gc_ref obj) {
+ if (!GC_GENERATIONAL)
+ return 0;
+
+ struct gc_heap *heap = mutator_heap(mut);
+ struct nofl_space *nofl_space = heap_nofl_space(heap);
+ if (nofl_space_contains(nofl_space, obj))
+ return nofl_space_is_survivor(nofl_space, obj);
+
+ struct large_object_space *lospace = heap_large_object_space(heap);
+ if (large_object_space_contains(lospace, obj))
+ return large_object_space_is_survivor(lospace, obj);
+
+ return 0;
+}
+
void
gc_write_barrier_slow(struct gc_mutator *mut, struct gc_ref obj,
size_t obj_size, struct gc_edge edge,
@@ -887,7 +904,7 @@ gc_write_barrier_slow(struct gc_mutator *mut, struct gc_ref
obj,
GC_ASSERT(obj_size > gc_allocator_large_threshold());
struct gc_heap *heap = mutator_heap(mut);
struct large_object_space *space = heap_large_object_space(heap);
- if (!large_object_space_is_old(space, obj))
+ if (!large_object_space_is_survivor(space, obj))
return;
if (gc_object_set_remembered(obj))
large_object_space_remember_object(space, obj);
diff --git a/src/nofl-space.h b/src/nofl-space.h
index 93904aee5..e47162853 100644
--- a/src/nofl-space.h
+++ b/src/nofl-space.h
@@ -1431,6 +1431,15 @@ nofl_space_pin_object(struct nofl_space *space, struct
gc_ref ref) {
memory_order_acquire));
}
+static inline int
+nofl_space_is_survivor(struct nofl_space *space, struct gc_ref ref) {
+ uint8_t *metadata = nofl_metadata_byte_for_object(ref);
+ uint8_t mask = NOFL_METADATA_BYTE_MARK_0
+ | NOFL_METADATA_BYTE_MARK_1 | NOFL_METADATA_BYTE_MARK_2;
+ uint8_t byte = atomic_load_explicit(metadata, memory_order_relaxed);
+ return byte & mask;
+}
+
static inline int
nofl_space_evacuate(struct nofl_space *space, uint8_t *metadata, uint8_t byte,
struct gc_edge edge,
diff --git a/src/pcc.c b/src/pcc.c
index 10d5f8382..593f43fc6 100644
--- a/src/pcc.c
+++ b/src/pcc.c
@@ -483,6 +483,11 @@ void gc_pin_object(struct gc_mutator *mut, struct gc_ref
ref) {
GC_CRASH();
}
+int gc_object_is_old_generation_slow(struct gc_mutator *mut,
+ struct gc_ref obj) {
+ return 0;
+}
+
void gc_write_barrier_slow(struct gc_mutator *mut, struct gc_ref obj,
size_t obj_size, struct gc_edge edge,
struct gc_ref new_val) {
diff --git a/src/semi.c b/src/semi.c
index aab5af233..ca7a31607 100644
--- a/src/semi.c
+++ b/src/semi.c
@@ -453,6 +453,11 @@ void gc_collect(struct gc_mutator *mut,
collect(mut, 0);
}
+int gc_object_is_old_generation_slow(struct gc_mutator *mut,
+ struct gc_ref obj) {
+ return 0;
+}
+
void gc_write_barrier_slow(struct gc_mutator *mut, struct gc_ref obj,
size_t obj_size, struct gc_edge edge,
struct gc_ref new_val) {
