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Merge pull request #5328 from laytan/compat-allocator-improvements

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mem: compat allocator improvements
This commit is contained in:
Laytan
2025-06-13 19:41:58 +02:00
committed by GitHub
parent f03484e352 67a8b035db
commit aa0cffb412
1 changed files with 57 additions and 21 deletions
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78
core/mem/allocators.odin
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@@ -2296,7 +2296,7 @@ buddy_allocator_proc :: proc(
// on the old size to work.
//
// The overhead of this allocator is an extra max(alignment, size_of(Header)) bytes allocated for each allocation, these bytes are
// used to store the size and original pointer.
// used to store the size and alignment.
Compat_Allocator :: struct {
parent: Allocator,
}
@@ -2316,51 +2316,87 @@ compat_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
size, alignment: int,
old_memory: rawptr, old_size: int,
location := #caller_location) -> (data: []byte, err: Allocator_Error) {
size, old_size := size, old_size
Header :: struct {
size: int,
ptr: rawptr,
size: int,
alignment: int,
}
@(no_sanitize_address)
get_unpoisoned_header :: #force_inline proc(ptr: rawptr) -> Header {
header := ([^]Header)(ptr)[-1]
a := max(header.alignment, size_of(Header))
sanitizer.address_unpoison(rawptr(uintptr(ptr)-uintptr(a)), a)
return header
}
rra := (^Compat_Allocator)(allocator_data)
switch mode {
case .Alloc, .Alloc_Non_Zeroed:
a := max(alignment, size_of(Header))
size += a
assert(size >= 0, "overflow")
a := max(alignment, size_of(Header))
req_size := size + a
assert(req_size >= 0, "overflow")
allocation := rra.parent.procedure(rra.parent.data, mode, size, alignment, old_memory, old_size, location) or_return
allocation := rra.parent.procedure(rra.parent.data, mode, req_size, alignment, old_memory, old_size, location) or_return
#no_bounds_check data = allocation[a:]
([^]Header)(raw_data(data))[-1] = {
size = size,
ptr = raw_data(allocation),
size = size,
alignment = alignment,
}
sanitizer.address_poison(raw_data(allocation), a)
return
case .Free:
header := ([^]Header)(old_memory)[-1]
return rra.parent.procedure(rra.parent.data, mode, size, alignment, header.ptr, header.size, location)
header := get_unpoisoned_header(old_memory)
a := max(header.alignment, size_of(Header))
orig_ptr := rawptr(uintptr(old_memory)-uintptr(a))
orig_size := header.size + a
return rra.parent.procedure(rra.parent.data, mode, orig_size, header.alignment, orig_ptr, orig_size, location)
case .Resize, .Resize_Non_Zeroed:
header := ([^]Header)(old_memory)[-1]
header := get_unpoisoned_header(old_memory)
orig_a := max(header.alignment, size_of(Header))
orig_ptr := rawptr(uintptr(old_memory)-uintptr(orig_a))
orig_size := header.size + orig_a
a := max(alignment, size_of(header))
size += a
new_alignment := max(header.alignment, alignment)
a := max(new_alignment, size_of(header))
req_size := size + a
assert(size >= 0, "overflow")
allocation := rra.parent.procedure(rra.parent.data, mode, size, alignment, header.ptr, header.size, location) or_return
allocation := rra.parent.procedure(rra.parent.data, mode, req_size, new_alignment, orig_ptr, orig_size, location) or_return
#no_bounds_check data = allocation[a:]
([^]Header)(raw_data(data))[-1] = {
size = size,
ptr = raw_data(allocation),
size = size,
alignment = new_alignment,
}
sanitizer.address_poison(raw_data(allocation), a)
return
case .Free_All:
return rra.parent.procedure(rra.parent.data, mode, size, alignment, old_memory, old_size, location)
case .Query_Info:
info := (^Allocator_Query_Info)(old_memory)
if info != nil && info.pointer != nil {
header := get_unpoisoned_header(info.pointer)
info.size = header.size
info.alignment = header.alignment
}
return
case .Free_All, .Query_Info, .Query_Features:
return rra.parent.procedure(rra.parent.data, mode, size, alignment, old_memory, old_size, location)
case .Query_Features:
data, err = rra.parent.procedure(rra.parent.data, mode, size, alignment, old_memory, old_size, location)
if err != nil {
set := (^Allocator_Mode_Set)(old_memory)
set^ += {.Query_Info}
}
return
case: unreachable()
}