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Mostly implementation-independent inline allocation

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This is a step towards separate compilation of the GC without losing
performance.  Only remaining task is the write barrier.
This commit is contained in:
Andy Wingo 2022-08-15 11:17:15 +02:00
parent 4d8a7169d0
commit a75842be90
4 changed files with 225 additions and 62 deletions
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96
gc-api.h
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@ -23,6 +23,10 @@ struct gc_option {
double value;
};
struct gc_mutator {
void *user_data;
};
// FIXME: Conflict with bdw-gc GC_API. Switch prefix?
#ifndef GC_API_
#define GC_API_ static
@ -38,8 +42,96 @@ GC_API_ void gc_finish_for_thread(struct mutator *mut);
GC_API_ void* gc_call_without_gc(struct mutator *mut, void* (*f)(void*),
void *data) GC_NEVER_INLINE;
GC_API_ inline void* gc_allocate(struct mutator *mut, size_t bytes);
GC_API_ void* gc_allocate_small(struct mutator *mut, size_t bytes) GC_NEVER_INLINE;
GC_API_ void* gc_allocate_large(struct mutator *mut, size_t bytes) GC_NEVER_INLINE;
static inline void* gc_allocate(struct mutator *mut, size_t bytes) GC_ALWAYS_INLINE;
// FIXME: remove :P
GC_API_ inline void* gc_allocate_pointerless(struct mutator *mut, size_t bytes);
static inline void* gc_allocate_pointerless(struct mutator *mut, size_t bytes);
enum gc_allocator_kind {
GC_ALLOCATOR_INLINE_BUMP_POINTER,
GC_ALLOCATOR_INLINE_FREELIST,
GC_ALLOCATOR_INLINE_NONE
};
static inline enum gc_allocator_kind gc_allocator_kind(void) GC_ALWAYS_INLINE;
static inline size_t gc_allocator_large_threshold(void) GC_ALWAYS_INLINE;
static inline size_t gc_allocator_small_granule_size(void) GC_ALWAYS_INLINE;
static inline size_t gc_allocator_allocation_pointer_offset(void) GC_ALWAYS_INLINE;
static inline size_t gc_allocator_allocation_limit_offset(void) GC_ALWAYS_INLINE;
static inline size_t gc_allocator_freelist_offset(size_t size) GC_ALWAYS_INLINE;
static inline void gc_allocator_inline_success(struct mutator *mut,
struct gc_ref obj,
uintptr_t aligned_size);
static inline void gc_allocator_inline_failure(struct mutator *mut,
uintptr_t aligned_size);
static inline void*
gc_allocate_bump_pointer(struct mutator *mut, size_t size) GC_ALWAYS_INLINE;
static inline void* gc_allocate_bump_pointer(struct mutator *mut, size_t size) {
GC_ASSERT(size <= gc_allocator_large_threshold());
size_t granule_size = gc_allocator_small_granule_size();
size_t hp_offset = gc_allocator_allocation_pointer_offset();
size_t limit_offset = gc_allocator_allocation_limit_offset();
uintptr_t base_addr = (uintptr_t)mut;
uintptr_t *hp_loc = (uintptr_t*)(base_addr + hp_offset);
uintptr_t *limit_loc = (uintptr_t*)(base_addr + limit_offset);
size = (size + granule_size - 1) & ~(granule_size - 1);
uintptr_t hp = *hp_loc;
uintptr_t limit = *limit_loc;
uintptr_t new_hp = hp + size;
if (GC_UNLIKELY (new_hp > limit)) {
gc_allocator_inline_failure(mut, size);
return gc_allocate_small(mut, size);
}
gc_allocator_inline_success(mut, gc_ref(hp), size);
*hp_loc = new_hp;
return (void*)hp;
}
static inline void* gc_allocate_freelist(struct mutator *mut,
size_t size) GC_ALWAYS_INLINE;
static inline void* gc_allocate_freelist(struct mutator *mut, size_t size) {
GC_ASSERT(size <= gc_allocator_large_threshold());
size_t freelist_offset = gc_allocator_freelist_offset(size);
uintptr_t base_addr = (uintptr_t)mut;
void **freelist_loc = (void**)(base_addr + freelist_offset);
void *head = *freelist_loc;
if (GC_UNLIKELY(!head))
return gc_allocate_small(mut, size);
*freelist_loc = *(void**)head;
return head;
}
static inline void* gc_allocate(struct mutator *mut, size_t size) {
GC_ASSERT(size != 0);
if (size > gc_allocator_large_threshold())
return gc_allocate_large(mut, size);
switch (gc_allocator_kind()) {
case GC_ALLOCATOR_INLINE_BUMP_POINTER:
return gc_allocate_bump_pointer(mut, size);
case GC_ALLOCATOR_INLINE_FREELIST:
return gc_allocate_freelist(mut, size);
case GC_ALLOCATOR_INLINE_NONE:
return gc_allocate_small(mut, size);
default:
abort();
}
}
#endif // GC_API_H_