mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-02-13 12:59:04 +00:00
Code Issues Packages Projects Releases Wiki Activity

new allocator interface

Browse Source
This commit is contained in:
Jonathan Marler 2020-04-17 14:15:36 -06:00
parent 129a4fb251
commit dc9648f868
10 changed files with 630 additions and 467 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
lib/std/array_list.zig
View File

@ -219,7 +219,8 @@ pub fn ArrayListAligned(comptime T: type, comptime alignment: ?u29) type {
if (better_capacity >= new_capacity) break;
}
const new_memory = try self.allocator.realloc(self.allocatedSlice(), better_capacity);
const new_memory = try self.allocator.reallocAtLeast(self.allocatedSlice(), better_capacity);
assert(new_memory.len >= better_capacity);
self.items.ptr = new_memory.ptr;
self.capacity = new_memory.len;
}
@ -441,7 +442,8 @@ pub fn ArrayListAlignedUnmanaged(comptime T: type, comptime alignment: ?u29) typ
if (better_capacity >= new_capacity) break;
}
const new_memory = try allocator.realloc(self.allocatedSlice(), better_capacity);
const new_memory = try allocator.reallocAtLeast(self.allocatedSlice(), better_capacity);
assert(new_memory.len >= better_capacity);
self.items.ptr = new_memory.ptr;
self.capacity = new_memory.len;
}

11
lib/std/c.zig
View File

@ -232,6 +232,17 @@ pub extern "c" fn setuid(uid: c_uint) c_int;
pub extern "c" fn aligned_alloc(alignment: usize, size: usize) ?*c_void;
pub extern "c" fn malloc(usize) ?*c_void;
pub usingnamespace switch (builtin.os.tag) {
.linux, .freebsd, .kfreebsd, .netbsd, .openbsd => struct {
pub extern "c" fn malloc_usable_size(?*const c_void) usize;
},
.macosx, .ios, .watchos, .tvos => struct {
pub extern "c" fn malloc_size(?*const c_void) usize;
},
else => struct {},
};
pub extern "c" fn realloc(?*c_void, usize) ?*c_void;
pub extern "c" fn free(*c_void) void;
pub extern "c" fn posix_memalign(memptr: **c_void, alignment: usize, size: usize) c_int;

602
lib/std/heap.zig
View File

@ -15,48 +15,88 @@ pub const ArenaAllocator = @import("heap/arena_allocator.zig").ArenaAllocator;
const Allocator = mem.Allocator;
pub const c_allocator = &c_allocator_state;
var c_allocator_state = Allocator{
.reallocFn = cRealloc,
.shrinkFn = cShrink,
usingnamespace if (comptime @hasDecl(c, "malloc_size")) struct {
pub const supports_malloc_size = true;
pub const malloc_size = c.malloc_size;
} else if (comptime @hasDecl(c, "malloc_usable_size")) struct {
pub const supports_malloc_size = true;
pub const malloc_size = c.malloc_usable_size;
} else struct {
pub const supports_malloc_size = false;
};
fn cRealloc(self: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
assert(new_align <= @alignOf(c_longdouble));
const old_ptr = if (old_mem.len == 0) null else @ptrCast(*c_void, old_mem.ptr);
const buf = c.realloc(old_ptr, new_size) orelse return error.OutOfMemory;
return @ptrCast([*]u8, buf)[0..new_size];
pub const c_allocator = mem.getAllocatorPtr(&c_allocator_state);
var c_allocator_state = Allocator{
.allocFn = cAlloc,
.resizeFn = cResize,
};
fn cAlloc(self: *Allocator, len: usize, ptr_align: u29, len_align: u29) Allocator.Error![]u8 {
assert(ptr_align <= @alignOf(c_longdouble));
const ptr = @ptrCast([*]u8, c.malloc(len) orelse return error.OutOfMemory);
if (len_align == 0) {
return ptr[0..len];
}
const full_len = init: {
if (comptime supports_malloc_size) {
const s = malloc_size(ptr);
assert(s >= len);
break :init s;
}
break :init len;
};
return ptr[0..mem.alignBackwardAnyAlign(full_len, len_align)];
}
fn cShrink(self: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
const old_ptr = @ptrCast(*c_void, old_mem.ptr);
const buf = c.realloc(old_ptr, new_size) orelse return old_mem[0..new_size];
return @ptrCast([*]u8, buf)[0..new_size];
fn cResize(self: *Allocator, buf: []u8, new_len: usize, len_align: u29) Allocator.Error!usize {
if (new_len == 0) {
c.free(buf.ptr);
return 0;
}
if (new_len <= buf.len) {
return mem.alignAllocLen(buf.len, new_len, len_align);
}
if (comptime supports_malloc_size) {
const full_len = malloc_size(buf.ptr);
if (new_len <= full_len) {
return mem.alignAllocLen(full_len, new_len, len_align);
}
}
// TODO: could we still use realloc? are there any cases where we can guarantee that realloc won't move memory?
return error.OutOfMemory;
}
/// This allocator makes a syscall directly for every allocation and free.
/// Thread-safe and lock-free.
pub const page_allocator = if (std.Target.current.isWasm())
&wasm_page_allocator_state
mem.getAllocatorPtr(&wasm_page_allocator_state)
else if (std.Target.current.os.tag == .freestanding)
root.os.heap.page_allocator
else
&page_allocator_state;
mem.getAllocatorPtr(&page_allocator_state);
var page_allocator_state = Allocator{
.reallocFn = PageAllocator.realloc,
.shrinkFn = PageAllocator.shrink,
.allocFn = PageAllocator.alloc,
.resizeFn = PageAllocator.resize,
};
var wasm_page_allocator_state = Allocator{
.reallocFn = WasmPageAllocator.realloc,
.shrinkFn = WasmPageAllocator.shrink,
.allocFn = WasmPageAllocator.alloc,
.resizeFn = WasmPageAllocator.resize,
};
pub const direct_allocator = @compileError("deprecated; use std.heap.page_allocator");
/// Verifies that the adjusted length will still map to the full length
pub fn alignPageAllocLen(full_len: usize, len: usize, len_align: u29) usize {
const aligned_len = mem.alignAllocLen(full_len, len, len_align);
assert(mem.alignForward(aligned_len, mem.page_size) == full_len);
return aligned_len;
}
const PageAllocator = struct {
fn alloc(allocator: *Allocator, n: usize, alignment: u29) error{OutOfMemory}![]u8 {
if (n == 0) return &[0]u8{};
fn alloc(allocator: *Allocator, n: usize, alignment: u29, len_align: u29) error{OutOfMemory}![]u8 {
assert(n > 0);
const alignedLen = mem.alignForward(n, mem.page_size);
if (builtin.os.tag == .windows) {
const w = os.windows;
@ -68,21 +108,21 @@ const PageAllocator = struct {
// see https://devblogs.microsoft.com/oldnewthing/?p=42223
const addr = w.VirtualAlloc(
null,
n,
alignedLen,
w.MEM_COMMIT | w.MEM_RESERVE,
w.PAGE_READWRITE,
) catch return error.OutOfMemory;
// If the allocation is sufficiently aligned, use it.
if (@ptrToInt(addr) & (alignment - 1) == 0) {
return @ptrCast([*]u8, addr)[0..n];
return @ptrCast([*]u8, addr)[0..alignPageAllocLen(alignedLen, n, len_align)];
}
// If it wasn't, actually do an explicitely aligned allocation.
w.VirtualFree(addr, 0, w.MEM_RELEASE);
const alloc_size = n + alignment;
const alloc_size = n + alignment - mem.page_size;
const final_addr = while (true) {
while (true) {
// Reserve a range of memory large enough to find a sufficiently
// aligned address.
const reserved_addr = w.VirtualAlloc(
@ -102,48 +142,50 @@ const PageAllocator = struct {
// until it succeeds.
const ptr = w.VirtualAlloc(
@intToPtr(*c_void, aligned_addr),
n,
alignedLen,
w.MEM_COMMIT | w.MEM_RESERVE,
w.PAGE_READWRITE,
) catch continue;
return @ptrCast([*]u8, ptr)[0..n];
};
return @ptrCast([*]u8, final_addr)[0..n];
return @ptrCast([*]u8, ptr)[0..alignPageAllocLen(alignedLen, n, len_align)];
}
}
const alloc_size = if (alignment <= mem.page_size) n else n + alignment;
const maxDropLen = alignment - std.math.min(alignment, mem.page_size);
const allocLen = if (maxDropLen <= alignedLen - n) alignedLen
else mem.alignForward(alignedLen + maxDropLen, mem.page_size);
const slice = os.mmap(
null,
mem.alignForward(alloc_size, mem.page_size),
allocLen,
os.PROT_READ | os.PROT_WRITE,
os.MAP_PRIVATE | os.MAP_ANONYMOUS,
-1,
0,
) catch return error.OutOfMemory;
if (alloc_size == n) return slice[0..n];
assert(mem.isAligned(@ptrToInt(slice.ptr), mem.page_size));
const aligned_addr = mem.alignForward(@ptrToInt(slice.ptr), alignment);
// Unmap the extra bytes that were only requested in order to guarantee
// that the range of memory we were provided had a proper alignment in
// it somewhere. The extra bytes could be at the beginning, or end, or both.
const unused_start_len = aligned_addr - @ptrToInt(slice.ptr);
if (unused_start_len != 0) {
os.munmap(slice[0..unused_start_len]);
}
const aligned_end_addr = mem.alignForward(aligned_addr + n, mem.page_size);
const unused_end_len = @ptrToInt(slice.ptr) + slice.len - aligned_end_addr;
if (unused_end_len != 0) {
os.munmap(@intToPtr([*]align(mem.page_size) u8, aligned_end_addr)[0..unused_end_len]);
const dropLen = aligned_addr - @ptrToInt(slice.ptr);
if (dropLen != 0) {
os.munmap(slice[0..dropLen]);
}
return @intToPtr([*]u8, aligned_addr)[0..n];
// Unmap extra pages
const alignedBufferLen = allocLen - dropLen;
if (alignedBufferLen > alignedLen) {
os.munmap(@alignCast(mem.page_size, @intToPtr([*]u8, aligned_addr))[alignedLen..alignedBufferLen]);
}
return @intToPtr([*]u8, aligned_addr)[0..alignPageAllocLen(alignedLen, n, len_align)];
}
fn shrink(allocator: *Allocator, old_mem_unaligned: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
const old_mem = @alignCast(mem.page_size, old_mem_unaligned);
fn resize(allocator: *Allocator, buf_unaligned: []u8, new_size: usize, len_align: u29) Allocator.Error!usize {
const new_size_aligned = mem.alignForward(new_size, mem.page_size);
if (builtin.os.tag == .windows) {
const w = os.windows;
if (new_size == 0) {
@ -153,100 +195,45 @@ const PageAllocator = struct {
// is reserved in the initial allocation call to VirtualAlloc."
// So we can only use MEM_RELEASE when actually releasing the
// whole allocation.
w.VirtualFree(old_mem.ptr, 0, w.MEM_RELEASE);
} else {
const base_addr = @ptrToInt(old_mem.ptr);
const old_addr_end = base_addr + old_mem.len;
const new_addr_end = base_addr + new_size;
const new_addr_end_rounded = mem.alignForward(new_addr_end, mem.page_size);
if (old_addr_end > new_addr_end_rounded) {
w.VirtualFree(buf_unaligned.ptr, 0, w.MEM_RELEASE);
return 0;
}
if (new_size < buf_unaligned.len) {
const base_addr = @ptrToInt(buf_unaligned.ptr);
const old_addr_end = base_addr + buf_unaligned.len;
const new_addr_end = mem.alignForward(base_addr + new_size, mem.page_size);
if (old_addr_end > new_addr_end) {
// For shrinking that is not releasing, we will only
// decommit the pages not needed anymore.
w.VirtualFree(
@intToPtr(*c_void, new_addr_end_rounded),
old_addr_end - new_addr_end_rounded,
@intToPtr(*c_void, new_addr_end),
old_addr_end - new_addr_end,
w.MEM_DECOMMIT,
);
}
return alignPageAllocLen(new_size_aligned, new_size, len_align);
}
return old_mem[0..new_size];
}
const base_addr = @ptrToInt(old_mem.ptr);
const old_addr_end = base_addr + old_mem.len;
const new_addr_end = base_addr + new_size;
const new_addr_end_rounded = mem.alignForward(new_addr_end, mem.page_size);
if (old_addr_end > new_addr_end_rounded) {
const ptr = @intToPtr([*]align(mem.page_size) u8, new_addr_end_rounded);
os.munmap(ptr[0 .. old_addr_end - new_addr_end_rounded]);
}
return old_mem[0..new_size];
}
fn realloc(allocator: *Allocator, old_mem_unaligned: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
const old_mem = @alignCast(mem.page_size, old_mem_unaligned);
if (builtin.os.tag == .windows) {
if (old_mem.len == 0) {
return alloc(allocator, new_size, new_align);
if (new_size == buf_unaligned.len) {
return alignPageAllocLen(new_size_aligned, new_size, len_align);
}
if (new_size <= old_mem.len and new_align <= old_align) {
return shrink(allocator, old_mem, old_align, new_size, new_align);
}
const w = os.windows;
const base_addr = @ptrToInt(old_mem.ptr);
if (new_align > old_align and base_addr & (new_align - 1) != 0) {
// Current allocation doesn't satisfy the new alignment.
// For now we'll do a new one no matter what, but maybe
// there is something smarter to do instead.
const result = try alloc(allocator, new_size, new_align);
assert(old_mem.len != 0);
@memcpy(result.ptr, old_mem.ptr, std.math.min(old_mem.len, result.len));
w.VirtualFree(old_mem.ptr, 0, w.MEM_RELEASE);
return result;
}
const old_addr_end = base_addr + old_mem.len;
const old_addr_end_rounded = mem.alignForward(old_addr_end, mem.page_size);
const new_addr_end = base_addr + new_size;
const new_addr_end_rounded = mem.alignForward(new_addr_end, mem.page_size);
if (new_addr_end_rounded == old_addr_end_rounded) {
// The reallocation fits in the already allocated pages.
return @ptrCast([*]u8, old_mem.ptr)[0..new_size];
}
assert(new_addr_end_rounded > old_addr_end_rounded);
// We need to commit new pages.
const additional_size = new_addr_end - old_addr_end_rounded;
const realloc_addr = w.kernel32.VirtualAlloc(
@intToPtr(*c_void, old_addr_end_rounded),
additional_size,
w.MEM_COMMIT | w.MEM_RESERVE,
w.PAGE_READWRITE,
) orelse {
// Committing new pages at the end of the existing allocation
// failed, we need to try a new one.
const new_alloc_mem = try alloc(allocator, new_size, new_align);
@memcpy(new_alloc_mem.ptr, old_mem.ptr, old_mem.len);
w.VirtualFree(old_mem.ptr, 0, w.MEM_RELEASE);
return new_alloc_mem;
};
assert(@ptrToInt(realloc_addr) == old_addr_end_rounded);
return @ptrCast([*]u8, old_mem.ptr)[0..new_size];
// new_size > buf_unaligned.len not implemented
return error.OutOfMemory;
}
if (new_size <= old_mem.len and new_align <= old_align) {
return shrink(allocator, old_mem, old_align, new_size, new_align);
const buf_aligned_len = mem.alignForward(buf_unaligned.len, mem.page_size);
if (new_size_aligned == buf_aligned_len)
return alignPageAllocLen(new_size_aligned, new_size, len_align);
if (new_size_aligned < buf_aligned_len) {
const ptr = @intToPtr([*]align(mem.page_size) u8, @ptrToInt(buf_unaligned.ptr) + new_size_aligned);
os.munmap(ptr[0 .. buf_aligned_len - new_size_aligned]);
if (new_size_aligned == 0)
return 0;
return alignPageAllocLen(new_size_aligned, new_size, len_align);
}
const result = try alloc(allocator, new_size, new_align);
if (old_mem.len != 0) {
@memcpy(result.ptr, old_mem.ptr, std.math.min(old_mem.len, result.len));
os.munmap(old_mem);
}
return result;
// TODO: call mremap
return error.OutOfMemory;
}
};
@ -338,16 +325,24 @@ const WasmPageAllocator = struct {
}
fn nPages(memsize: usize) usize {
return std.mem.alignForward(memsize, std.mem.page_size) / std.mem.page_size;
return mem.alignForward(memsize, mem.page_size) / mem.page_size;
}
fn alloc(allocator: *Allocator, page_count: usize, alignment: u29) error{OutOfMemory}!usize {
var idx = conventional.useRecycled(page_count);
if (idx != FreeBlock.not_found) {
return idx;
fn alloc(allocator: *Allocator, len: usize, alignment: u29, len_align: u29) error{OutOfMemory}![]u8 {
const page_count = nPages(len);
const page_idx = try allocPages(page_count);
return @intToPtr([*]u8, page_idx * mem.page_size)
[0..alignPageAllocLen(page_count * mem.page_size, len, len_align)];
}
fn allocPages(page_count: usize) !usize {
{
const idx = conventional.useRecycled(page_count);
if (idx != FreeBlock.not_found) {
return idx;
}
}
idx = extended.useRecycled(page_count);
const idx = extended.useRecycled(page_count);
if (idx != FreeBlock.not_found) {
return idx + extendedOffset();
}
@ -360,51 +355,36 @@ const WasmPageAllocator = struct {
return @intCast(usize, prev_page_count);
}
pub fn realloc(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) Allocator.Error![]u8 {
if (new_align > std.mem.page_size) {
return error.OutOfMemory;
fn freePages(start: usize, end: usize) void {
if (start < extendedOffset()) {
conventional.recycle(start, std.math.min(extendedOffset(), end) - start);
}
if (end > extendedOffset()) {
var new_end = end;
if (!extended.isInitialized()) {
// Steal the last page from the memory currently being recycled
// TODO: would it be better if we use the first page instead?
new_end -= 1;
if (nPages(new_size) == nPages(old_mem.len)) {
return old_mem.ptr[0..new_size];
} else if (new_size < old_mem.len) {
return shrink(allocator, old_mem, old_align, new_size, new_align);
} else {
const page_idx = try alloc(allocator, nPages(new_size), new_align);
const new_mem = @intToPtr([*]u8, page_idx * std.mem.page_size)[0..new_size];
std.mem.copy(u8, new_mem, old_mem);
_ = shrink(allocator, old_mem, old_align, 0, 0);
return new_mem;
extended.data = @intToPtr([*]u128, new_end * mem.page_size)[0 .. mem.page_size / @sizeOf(u128)];
// Since this is the first page being freed and we consume it, assume *nothing* is free.
mem.set(u128, extended.data, PageStatus.none_free);
}
const clamped_start = std.math.max(extendedOffset(), start);
extended.recycle(clamped_start - extendedOffset(), new_end - clamped_start);
}
}
pub fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
@setCold(true);
const free_start = nPages(@ptrToInt(old_mem.ptr) + new_size);
var free_end = nPages(@ptrToInt(old_mem.ptr) + old_mem.len);
if (free_end > free_start) {
if (free_start < extendedOffset()) {
const clamped_end = std.math.min(extendedOffset(), free_end);
conventional.recycle(free_start, clamped_end - free_start);
}
if (free_end > extendedOffset()) {
if (!extended.isInitialized()) {
// Steal the last page from the memory currently being recycled
// TODO: would it be better if we use the first page instead?
free_end -= 1;
extended.data = @intToPtr([*]u128, free_end * std.mem.page_size)[0 .. std.mem.page_size / @sizeOf(u128)];
// Since this is the first page being freed and we consume it, assume *nothing* is free.
std.mem.set(u128, extended.data, PageStatus.none_free);
}
const clamped_start = std.math.max(extendedOffset(), free_start);
extended.recycle(clamped_start - extendedOffset(), free_end - clamped_start);
}
fn resize(allocator: *Allocator, buf: []u8, new_len: usize, len_align: u29) error{OutOfMemory}!usize {
const aligned_len = mem.alignForward(buf.len, mem.page_size);
if (new_len > aligned_len) return error.OutOfMemory;
const current_n = nPages(aligned_len);
const new_n = nPages(new_len);
if (new_n != current_n) {
const base = nPages(@ptrToInt(buf.ptr));
freePages(base + new_n, base + current_n);
}
return old_mem[0..new_size];
return if (new_len == 0) 0 else alignPageAllocLen(new_n * mem.page_size, new_len, len_align);
}
};
@ -418,8 +398,8 @@ pub const HeapAllocator = switch (builtin.os.tag) {
pub fn init() HeapAllocator {
return HeapAllocator{
.allocator = Allocator{
.reallocFn = realloc,
.shrinkFn = shrink,
.allocFn = alloc,
.resizeFn = resize,
},
.heap_handle = null,
};
@ -431,11 +411,14 @@ pub const HeapAllocator = switch (builtin.os.tag) {
}
}
fn alloc(allocator: *Allocator, n: usize, alignment: u29) error{OutOfMemory}![]u8 {
const self = @fieldParentPtr(HeapAllocator, "allocator", allocator);
if (n == 0) return &[0]u8{};
fn getRecordPtr(buf: []u8) *align(1) usize {
return @intToPtr(*align(1) usize, @ptrToInt(buf.ptr) + buf.len);
}
const amt = n + alignment + @sizeOf(usize);
fn alloc(allocator: *Allocator, n: usize, ptr_align: u29, len_align: u29) error{OutOfMemory}![]u8 {
const self = @fieldParentPtr(HeapAllocator, "allocator", allocator);
const amt = n + ptr_align - 1 + @sizeOf(usize);
const optional_heap_handle = @atomicLoad(?HeapHandle, &self.heap_handle, builtin.AtomicOrder.SeqCst);
const heap_handle = optional_heap_handle orelse blk: {
const options = if (builtin.single_threaded) os.windows.HEAP_NO_SERIALIZE else 0;
@ -446,66 +429,60 @@ pub const HeapAllocator = switch (builtin.os.tag) {
};
const ptr = os.windows.kernel32.HeapAlloc(heap_handle, 0, amt) orelse return error.OutOfMemory;
const root_addr = @ptrToInt(ptr);
const adjusted_addr = mem.alignForward(root_addr, alignment);
const record_addr = adjusted_addr + n;
@intToPtr(*align(1) usize, record_addr).* = root_addr;
return @intToPtr([*]u8, adjusted_addr)[0..n];
}
fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
return realloc(allocator, old_mem, old_align, new_size, new_align) catch {
const old_adjusted_addr = @ptrToInt(old_mem.ptr);
const old_record_addr = old_adjusted_addr + old_mem.len;
const root_addr = @intToPtr(*align(1) usize, old_record_addr).*;
const old_ptr = @intToPtr(*c_void, root_addr);
const new_record_addr = old_record_addr - new_size + old_mem.len;
@intToPtr(*align(1) usize, new_record_addr).* = root_addr;
return old_mem[0..new_size];
const aligned_addr = mem.alignForward(root_addr, ptr_align);
const return_len = init: {
if (len_align == 0) break :init n;
const full_len = os.windows.kernel32.HeapSize(heap_handle, 0, ptr);
assert(full_len != std.math.maxInt(usize));
assert(full_len >= amt);
break :init mem.alignBackwardAnyAlign(full_len - (aligned_addr - root_addr), len_align);
};
const buf = @intToPtr([*]u8, aligned_addr)[0..return_len];
getRecordPtr(buf).* = root_addr;
return buf;
}
fn realloc(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
if (old_mem.len == 0) return alloc(allocator, new_size, new_align);
fn resize(allocator: *Allocator, buf: []u8, new_size: usize, len_align: u29) error{OutOfMemory}!usize {
const self = @fieldParentPtr(HeapAllocator, "allocator", allocator);
const old_adjusted_addr = @ptrToInt(old_mem.ptr);
const old_record_addr = old_adjusted_addr + old_mem.len;
const root_addr = @intToPtr(*align(1) usize, old_record_addr).*;
const old_ptr = @intToPtr(*c_void, root_addr);
if (new_size == 0) {
os.windows.HeapFree(self.heap_handle.?, 0, old_ptr);
return old_mem[0..0];
os.windows.HeapFree(self.heap_handle.?, 0, @intToPtr(*c_void ,getRecordPtr(buf).*));
return 0;
}
const amt = new_size + new_align + @sizeOf(usize);
const root_addr = getRecordPtr(buf).*;
const align_offset = @ptrToInt(buf.ptr) - root_addr;
const amt = align_offset + new_size + @sizeOf(usize);
const new_ptr = os.windows.kernel32.HeapReAlloc(
self.heap_handle.?,
0,
old_ptr,
os.windows.HEAP_REALLOC_IN_PLACE_ONLY,
@intToPtr(*c_void, root_addr),
amt,
) orelse return error.OutOfMemory;
const offset = old_adjusted_addr - root_addr;
const new_root_addr = @ptrToInt(new_ptr);
var new_adjusted_addr = new_root_addr + offset;
const offset_is_valid = new_adjusted_addr + new_size + @sizeOf(usize) <= new_root_addr + amt;
const offset_is_aligned = new_adjusted_addr % new_align == 0;
if (!offset_is_valid or !offset_is_aligned) {
// If HeapReAlloc didn't happen to move the memory to the new alignment,
// or the memory starting at the old offset would be outside of the new allocation,
// then we need to copy the memory to a valid aligned address and use that
const new_aligned_addr = mem.alignForward(new_root_addr, new_align);
@memcpy(@intToPtr([*]u8, new_aligned_addr), @intToPtr([*]u8, new_adjusted_addr), std.math.min(old_mem.len, new_size));
new_adjusted_addr = new_aligned_addr;
}
const new_record_addr = new_adjusted_addr + new_size;
@intToPtr(*align(1) usize, new_record_addr).* = new_root_addr;
return @intToPtr([*]u8, new_adjusted_addr)[0..new_size];
assert(new_ptr == @intToPtr(*c_void, root_addr));
const return_len = init: {
if (len_align == 0) break :init new_size;
const full_len = os.windows.kernel32.HeapSize(self.heap_handle.?, 0, new_ptr);
assert(full_len != std.math.maxInt(usize));
assert(full_len >= amt);
break :init mem.alignBackwardAnyAlign(full_len - align_offset, len_align);
};
getRecordPtr(buf.ptr[0..return_len]).* = root_addr;
return return_len;
}
},
else => @compileError("Unsupported OS"),
};
fn sliceContainsPtr(container: []u8, ptr: [*]u8) bool {
return @ptrToInt(ptr) >= @ptrToInt(container.ptr) and
@ptrToInt(ptr) < (@ptrToInt(container.ptr) + container.len);
}
fn sliceContainsSlice(container: []u8, slice: []u8) bool {
return @ptrToInt(slice.ptr) >= @ptrToInt(container.ptr) and
(@ptrToInt(slice.ptr) + slice.len) <= (@ptrToInt(container.ptr) + container.len);
}
pub const FixedBufferAllocator = struct {
allocator: Allocator,
end_index: usize,
@ -514,19 +491,33 @@ pub const FixedBufferAllocator = struct {
pub fn init(buffer: []u8) FixedBufferAllocator {
return FixedBufferAllocator{
.allocator = Allocator{
.reallocFn = realloc,
.shrinkFn = shrink,
.allocFn = alloc,
.resizeFn = resize,
},
.buffer = buffer,
.end_index = 0,
};
}
fn alloc(allocator: *Allocator, n: usize, alignment: u29) ![]u8 {
pub fn ownsPtr(self: *FixedBufferAllocator, ptr: [*]u8) bool {
return sliceContainsPtr(self.buffer, ptr);
}
pub fn ownsSlice(self: *FixedBufferAllocator, slice: []u8) bool {
return sliceContainsSlice(self.buffer, slice);
}
// NOTE: this will not work in all cases, if the last allocation had an adjusted_index
// then we won't be able to determine what the last allocation was. This is because
// the alignForward operation done in alloc is not reverisible.
pub fn isLastAllocation(self: *FixedBufferAllocator, buf: []u8) bool {
return buf.ptr + buf.len == self.buffer.ptr + self.end_index;
}
fn alloc(allocator: *Allocator, n: usize, ptr_align: u29, len_align: u29) ![]u8 {
const self = @fieldParentPtr(FixedBufferAllocator, "allocator", allocator);
const addr = @ptrToInt(self.buffer.ptr) + self.end_index;
const adjusted_addr = mem.alignForward(addr, alignment);
const adjusted_index = self.end_index + (adjusted_addr - addr);
const aligned_addr = mem.alignForward(@ptrToInt(self.buffer.ptr) + self.end_index, ptr_align);
const adjusted_index = aligned_addr - @ptrToInt(self.buffer.ptr);
const new_end_index = adjusted_index + n;
if (new_end_index > self.buffer.len) {
return error.OutOfMemory;
@ -534,33 +525,32 @@ pub const FixedBufferAllocator = struct {
const result = self.buffer[adjusted_index..new_end_index];
self.end_index = new_end_index;
return result;
return result[0..mem.alignAllocLen(result.len, n, len_align)];
}
fn realloc(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
fn resize(allocator: *Allocator, buf: []u8, new_size: usize, len_align: u29) Allocator.Error!usize {
const self = @fieldParentPtr(FixedBufferAllocator, "allocator", allocator);
assert(old_mem.len <= self.end_index);
if (old_mem.ptr == self.buffer.ptr + self.end_index - old_mem.len and
mem.alignForward(@ptrToInt(old_mem.ptr), new_align) == @ptrToInt(old_mem.ptr))
{
const start_index = self.end_index - old_mem.len;
const new_end_index = start_index + new_size;
if (new_end_index > self.buffer.len) return error.OutOfMemory;
const result = self.buffer[start_index..new_end_index];
self.end_index = new_end_index;
return result;
} else if (new_size <= old_mem.len and new_align <= old_align) {
// We can't do anything with the memory, so tell the client to keep it.
return error.OutOfMemory;
} else {
const result = try alloc(allocator, new_size, new_align);
@memcpy(result.ptr, old_mem.ptr, std.math.min(old_mem.len, result.len));
return result;
}
}
assert(self.ownsSlice(buf)); // sanity check
fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
return old_mem[0..new_size];
if (!self.isLastAllocation(buf)) {
if (new_size > buf.len)
return error.OutOfMemory;
return if (new_size == 0) 0 else mem.alignAllocLen(buf.len, new_size, len_align);
}
if (new_size <= buf.len) {
const sub = buf.len - new_size;
self.end_index -= sub;
return if (new_size == 0) 0 else mem.alignAllocLen(buf.len - sub, new_size, len_align);
}
var add = new_size - buf.len;
if (add + self.end_index > self.buffer.len) {
//add = self.buffer.len - self.end_index;
return error.OutOfMemory;
}
self.end_index += add;
return mem.alignAllocLen(buf.len + add, new_size, len_align);
}
pub fn reset(self: *FixedBufferAllocator) void {
@ -581,20 +571,20 @@ pub const ThreadSafeFixedBufferAllocator = blk: {
pub fn init(buffer: []u8) ThreadSafeFixedBufferAllocator {
return ThreadSafeFixedBufferAllocator{
.allocator = Allocator{
.reallocFn = realloc,
.shrinkFn = shrink,
.allocFn = alloc,
.resizeFn = Allocator.noResize,
},
.buffer = buffer,
.end_index = 0,
};
}
fn alloc(allocator: *Allocator, n: usize, alignment: u29) ![]u8 {
fn alloc(allocator: *Allocator, n: usize, ptr_align: u29, len_align: u29) ![]u8 {
const self = @fieldParentPtr(ThreadSafeFixedBufferAllocator, "allocator", allocator);
var end_index = @atomicLoad(usize, &self.end_index, builtin.AtomicOrder.SeqCst);
while (true) {
const addr = @ptrToInt(self.buffer.ptr) + end_index;
const adjusted_addr = mem.alignForward(addr, alignment);
const adjusted_addr = mem.alignForward(addr, ptr_align);
const adjusted_index = end_index + (adjusted_addr - addr);
const new_end_index = adjusted_index + n;
if (new_end_index > self.buffer.len) {
@ -604,21 +594,6 @@ pub const ThreadSafeFixedBufferAllocator = blk: {
}
}
fn realloc(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
if (new_size <= old_mem.len and new_align <= old_align) {
// We can't do anything useful with the memory, tell the client to keep it.
return error.OutOfMemory;
} else {
const result = try alloc(allocator, new_size, new_align);
@memcpy(result.ptr, old_mem.ptr, std.math.min(old_mem.len, result.len));
return result;
}
}
fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
return old_mem[0..new_size];
}
pub fn reset(self: *ThreadSafeFixedBufferAllocator) void {
self.end_index = 0;
}
@ -632,8 +607,8 @@ pub fn stackFallback(comptime size: usize, fallback_allocator: *Allocator) Stack
.fallback_allocator = fallback_allocator,
.fixed_buffer_allocator = undefined,
.allocator = Allocator{
.reallocFn = StackFallbackAllocator(size).realloc,
.shrinkFn = StackFallbackAllocator(size).shrink,
.allocFn = StackFallbackAllocator(size).realloc,
.resizeFn = StackFallbackAllocator(size).resize,
},
};
}
@ -652,58 +627,19 @@ pub fn StackFallbackAllocator(comptime size: usize) type {
return &self.allocator;
}
fn realloc(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
fn alloc(allocator: *Allocator, len: usize, ptr_align: u29, len_align: u29) error{OutOfMemory}![*]u8 {
const self = @fieldParentPtr(Self, "allocator", allocator);
const in_buffer = @ptrToInt(old_mem.ptr) >= @ptrToInt(&self.buffer) and
@ptrToInt(old_mem.ptr) < @ptrToInt(&self.buffer) + self.buffer.len;
if (in_buffer) {
return FixedBufferAllocator.realloc(
&self.fixed_buffer_allocator.allocator,
old_mem,
old_align,
new_size,
new_align,
) catch {
const result = try self.fallback_allocator.reallocFn(
self.fallback_allocator,
&[0]u8{},
undefined,
new_size,
new_align,
);
mem.copy(u8, result, old_mem);
return result;
};
}
return self.fallback_allocator.reallocFn(
self.fallback_allocator,
old_mem,
old_align,
new_size,
new_align,
);
return FixedBufferAllocator.alloc(&self.fixed_buffer_allocator, len, ptr_align) catch
return fallback_allocator.alloc(len, ptr_align);
}
fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
fn resize(self: *Allocator, buf: []u8, new_len: usize, len_align: u29) error{OutOfMemory}!void {
const self = @fieldParentPtr(Self, "allocator", allocator);
const in_buffer = @ptrToInt(old_mem.ptr) >= @ptrToInt(&self.buffer) and
@ptrToInt(old_mem.ptr) < @ptrToInt(&self.buffer) + self.buffer.len;
if (in_buffer) {
return FixedBufferAllocator.shrink(
&self.fixed_buffer_allocator.allocator,
old_mem,
old_align,
new_size,
new_align,
);
if (self.fixed_buffer_allocator.ownsPtr(buf.ptr)) {
try self.fixed_buffer_allocator.callResizeFn(buf, new_len);
} else {
try self.fallback_allocator.callResizeFn(buf, new_len);
}
return self.fallback_allocator.shrinkFn(
self.fallback_allocator,
old_mem,
old_align,
new_size,
new_align,
);
}
};
}
@ -718,8 +654,8 @@ test "c_allocator" {
test "WasmPageAllocator internals" {
if (comptime std.Target.current.isWasm()) {
const conventional_memsize = WasmPageAllocator.conventional.totalPages() * std.mem.page_size;
const initial = try page_allocator.alloc(u8, std.mem.page_size);
const conventional_memsize = WasmPageAllocator.conventional.totalPages() * mem.page_size;
const initial = try page_allocator.alloc(u8, mem.page_size);
std.debug.assert(@ptrToInt(initial.ptr) < conventional_memsize); // If this isn't conventional, the rest of these tests don't make sense. Also we have a serious memory leak in the test suite.
var inplace = try page_allocator.realloc(initial, 1);
@ -799,7 +735,7 @@ test "ArenaAllocator" {
var test_fixed_buffer_allocator_memory: [800000 * @sizeOf(u64)]u8 = undefined;
test "FixedBufferAllocator" {
var fixed_buffer_allocator = FixedBufferAllocator.init(test_fixed_buffer_allocator_memory[0..]);
var fixed_buffer_allocator = mem.sanityWrap(FixedBufferAllocator.init(test_fixed_buffer_allocator_memory[0..]));
try testAllocator(&fixed_buffer_allocator.allocator);
try testAllocatorAligned(&fixed_buffer_allocator.allocator, 16);
@ -865,7 +801,10 @@ test "ThreadSafeFixedBufferAllocator" {
try testAllocatorAlignedShrink(&fixed_buffer_allocator.allocator);
}
fn testAllocator(allocator: *mem.Allocator) !void {
fn testAllocator(base_allocator: *mem.Allocator) !void {
var sanityAllocator = mem.sanityWrap(base_allocator);
const allocator = &sanityAllocator.allocator;
var slice = try allocator.alloc(*i32, 100);
testing.expect(slice.len == 100);
for (slice) |*item, i| {
@ -893,7 +832,10 @@ fn testAllocator(allocator: *mem.Allocator) !void {
allocator.free(slice);
}
fn testAllocatorAligned(allocator: *mem.Allocator, comptime alignment: u29) !void {
fn testAllocatorAligned(base_allocator: *mem.Allocator, comptime alignment: u29) !void {
var sanityAllocator = mem.sanityWrap(base_allocator);
const allocator = &sanityAllocator.allocator;
// initial
var slice = try allocator.alignedAlloc(u8, alignment, 10);
testing.expect(slice.len == 10);
@ -917,7 +859,10 @@ fn testAllocatorAligned(allocator: *mem.Allocator, comptime alignment: u29) !voi
testing.expect(slice.len == 0);
}
fn testAllocatorLargeAlignment(allocator: *mem.Allocator) mem.Allocator.Error!void {
fn testAllocatorLargeAlignment(base_allocator: *mem.Allocator) mem.Allocator.Error!void {
var sanityAllocator = mem.sanityWrap(base_allocator);
const allocator = &sanityAllocator.allocator;
//Maybe a platform's page_size is actually the same as or
// very near usize?
if (mem.page_size << 2 > maxInt(usize)) return;
@ -946,7 +891,10 @@ fn testAllocatorLargeAlignment(allocator: *mem.Allocator) mem.Allocator.Error!vo
allocator.free(slice);
}
fn testAllocatorAlignedShrink(allocator: *mem.Allocator) mem.Allocator.Error!void {
fn testAllocatorAlignedShrink(base_allocator: *mem.Allocator) mem.Allocator.Error!void {
var sanityAllocator = mem.sanityWrap(base_allocator);
const allocator = &sanityAllocator.allocator;
var debug_buffer: [1000]u8 = undefined;
const debug_allocator = &FixedBufferAllocator.init(&debug_buffer).allocator;

29
lib/std/heap/arena_allocator.zig
View File

@ -20,8 +20,8 @@ pub const ArenaAllocator = struct {
pub fn promote(self: State, child_allocator: *Allocator) ArenaAllocator {
return .{
.allocator = Allocator{
.reallocFn = realloc,
.shrinkFn = shrink,
.allocFn = alloc,
.resizeFn = Allocator.noResize,
},
.child_allocator = child_allocator,
.state = self,
@ -61,38 +61,23 @@ pub const ArenaAllocator = struct {
return buf_node;
}
fn alloc(allocator: *Allocator, n: usize, alignment: u29) ![]u8 {
fn alloc(allocator: *Allocator, n: usize, ptr_align: u29, len_align: u29) ![]u8 {
const self = @fieldParentPtr(ArenaAllocator, "allocator", allocator);
var cur_node = if (self.state.buffer_list.first) |first_node| first_node else try self.createNode(0, n + alignment);
var cur_node = if (self.state.buffer_list.first) |first_node| first_node else try self.createNode(0, n + ptr_align);
while (true) {
const cur_buf = cur_node.data[@sizeOf(BufNode)..];
const addr = @ptrToInt(cur_buf.ptr) + self.state.end_index;
const adjusted_addr = mem.alignForward(addr, alignment);
const adjusted_addr = mem.alignForward(addr, ptr_align);
const adjusted_index = self.state.end_index + (adjusted_addr - addr);
const new_end_index = adjusted_index + n;
if (new_end_index > cur_buf.len) {
cur_node = try self.createNode(cur_buf.len, n + alignment);
cur_node = try self.createNode(cur_buf.len, n + ptr_align);
continue;
}
const result = cur_buf[adjusted_index..new_end_index];
self.state.end_index = new_end_index;
return result;
return result[0..mem.alignAllocLen(result.len, n, len_align)];
}
}
fn realloc(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
if (new_size <= old_mem.len and new_align <= new_size) {
// We can't do anything with the memory, so tell the client to keep it.
return error.OutOfMemory;
} else {
const result = try alloc(allocator, new_size, new_align);
@memcpy(result.ptr, old_mem.ptr, std.math.min(old_mem.len, result.len));
return result;
}
}
fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
return old_mem[0..new_size];
}
};

61
lib/std/heap/logging_allocator.zig
View File

@ -15,39 +15,45 @@ pub fn LoggingAllocator(comptime OutStreamType: type) type {
pub fn init(parent_allocator: *Allocator, out_stream: OutStreamType) Self {
return Self{
.allocator = Allocator{
.reallocFn = realloc,
.shrinkFn = shrink,
.allocFn = alloc,
.resizeFn = resize,
},
.parent_allocator = parent_allocator,
.out_stream = out_stream,
};
}
fn realloc(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
fn alloc(allocator: *Allocator, len: usize, ptr_align: u29, len_align: u29) error{OutOfMemory}![]u8 {
const self = @fieldParentPtr(Self, "allocator", allocator);
if (old_mem.len == 0) {
self.out_stream.print("allocation of {} ", .{new_size}) catch {};
} else {
self.out_stream.print("resize from {} to {} ", .{ old_mem.len, new_size }) catch {};
}
const result = self.parent_allocator.reallocFn(self.parent_allocator, old_mem, old_align, new_size, new_align);
self.out_stream.print("alloc : {}", .{len}) catch {};
const result = self.parent_allocator.callAllocFn(len, ptr_align, len_align);
if (result) |buff| {
self.out_stream.print("success!\n", .{}) catch {};
self.out_stream.print(" success!\n", .{}) catch {};
} else |err| {
self.out_stream.print("failure!\n", .{}) catch {};
self.out_stream.print(" failure!\n", .{}) catch {};
}
return result;
}
fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
fn resize(allocator: *Allocator, buf: []u8, new_len: usize, len_align: u29) error{OutOfMemory}!usize {
const self = @fieldParentPtr(Self, "allocator", allocator);
const result = self.parent_allocator.shrinkFn(self.parent_allocator, old_mem, old_align, new_size, new_align);
if (new_size == 0) {
self.out_stream.print("free of {} bytes success!\n", .{old_mem.len}) catch {};
if (new_len == 0) {
self.out_stream.print("free : {}\n", .{buf.len}) catch {};
} else if (new_len <= buf.len) {
self.out_stream.print("shrink: {} to {}\n", .{buf.len, new_len}) catch {};
} else {
self.out_stream.print("shrink from {} bytes to {} bytes success!\n", .{ old_mem.len, new_size }) catch {};
self.out_stream.print("expand: {} to {}", .{ buf.len, new_len }) catch {};
}
if (self.parent_allocator.callResizeFn(buf, new_len, len_align)) |resized_len| {
if (new_len > buf.len) {
self.out_stream.print(" success!\n", .{}) catch {};
}
return resized_len;
} else |e| {
std.debug.assert(new_len > buf.len);
self.out_stream.print(" failure!\n", .{}) catch {};
return e;
}
return result;
}
};
}
@ -60,17 +66,24 @@ pub fn loggingAllocator(
}
test "LoggingAllocator" {
var buf: [255]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buf);
var log_buf: [255]u8 = undefined;
var fbs = std.io.fixedBufferStream(&log_buf);
const allocator = &loggingAllocator(std.testing.allocator, fbs.outStream()).allocator;
var allocator_buf: [10]u8 = undefined;
var fixedBufferAllocator = std.mem.sanityWrap(std.heap.FixedBufferAllocator.init(&allocator_buf));
const allocator = &loggingAllocator(&fixedBufferAllocator.allocator, fbs.outStream()).allocator;
const ptr = try allocator.alloc(u8, 10);
allocator.free(ptr);
var a = try allocator.alloc(u8, 10);
a.len = allocator.shrinkBytes(a, 5, 0);
std.debug.assert(a.len == 5);
std.testing.expectError(error.OutOfMemory, allocator.callResizeFn(a, 20, 0));
allocator.free(a);
std.testing.expectEqualSlices(u8,
\\allocation of 10 success!
\\free of 10 bytes success!
\\alloc : 10 success!
\\shrink: 10 to 5
\\expand: 5 to 20 failure!
\\free : 5
\\
, fbs.getWritten());
}

323
lib/std/mem.zig
View File

@ -16,6 +16,52 @@ pub const page_size = switch (builtin.arch) {
pub const Allocator = struct {
pub const Error = error{OutOfMemory};
/// Attempt to allocate at least `len` bytes aligned to `ptr_align`.
///
/// If `len_align` is `0`, then the length returned MUST be exactly `len` bytes,
/// otherwise, the length must be aligned to `len_align`.
///
/// `len` must be greater than or equal to `len_align` and must be aligned by `len_align`.
allocFn: fn (self: *Allocator, len: usize, ptr_align: u29, len_align: u29) Error![]u8,
/// Attempt to expand or shrink memory in place. `buf.len` must equal the most recent
/// length returned by `allocFn` or `resizeFn`.
///
/// Passing a `new_len` of 0 frees and invalidates the buffer such that it can no
/// longer be passed to `resizeFn`.
///
/// error.OutOfMemory can only be returned if `new_len` is greater than `buf.len`.
/// If `buf` cannot be expanded to accomodate `new_len`, then the allocation MUST be
/// unmodified and error.OutOfMemory MUST be returned.
///
/// If `len_align` is `0`, then the length returned MUST be exactly `len` bytes,
/// otherwise, the length must be aligned to `len_align`.
///
/// `new_len` must be greater than or equal to `len_align` and must be aligned by `len_align`.
resizeFn: fn (self: *Allocator, buf: []u8, new_len: usize, len_align: u29) Error!usize,
pub fn callAllocFn(self: *Allocator, new_len: usize, alignment: u29, len_align: u29) Error![]u8 {
return self.allocFn(self, new_len, alignment, len_align);
}
pub fn callResizeFn(self: *Allocator, buf: []u8, new_len: usize, len_align: u29) Error!usize {
return self.resizeFn(self, buf, new_len, len_align);
}
/// Set to resizeFn if in-place resize is not supported.
pub fn noResize(self: *Allocator, buf: []u8, new_len: usize, len_align: u29) Error!usize {
if (new_len > buf.len)
return error.OutOfMemory;
return new_len;
}
/// Call `resizeFn`, but caller guarantees that `new_len` <= `buf.len` meaning
/// error.OutOfMemory should be impossible.
pub fn shrinkBytes(self: *Allocator, buf: []u8, new_len: usize, len_align: u29) usize {
assert(new_len <= buf.len);
return self.callResizeFn(buf, new_len, len_align) catch unreachable;
}
/// Realloc is used to modify the size or alignment of an existing allocation,
/// as well as to provide the allocator with an opportunity to move an allocation
/// to a better location.
@ -24,7 +70,7 @@ pub const Allocator = struct {
/// When the size/alignment is less than or equal to the previous allocation,
/// this function returns `error.OutOfMemory` when the allocator decides the client
/// would be better off keeping the extra alignment/size. Clients will call
/// `shrinkFn` when they require the allocator to track a new alignment/size,
/// `callResizeFn` when they require the allocator to track a new alignment/size,
/// and so this function should only return success when the allocator considers
/// the reallocation desirable from the allocator's perspective.
/// As an example, `std.ArrayList` tracks a "capacity", and therefore can handle
@ -37,16 +83,15 @@ pub const Allocator = struct {
/// as `old_mem` was when `reallocFn` is called. The bytes of
/// `return_value[old_mem.len..]` have undefined values.
/// The returned slice must have its pointer aligned at least to `new_alignment` bytes.
reallocFn: fn (
fn reallocBytes(
self: *Allocator,
/// Guaranteed to be the same as what was returned from most recent call to
/// `reallocFn` or `shrinkFn`.
/// `allocFn` or `resizeFn`.
/// If `old_mem.len == 0` then this is a new allocation and `new_byte_count`
/// is guaranteed to be >= 1.
old_mem: []u8,
/// If `old_mem.len == 0` then this is `undefined`, otherwise:
/// Guaranteed to be the same as what was returned from most recent call to
/// `reallocFn` or `shrinkFn`.
/// Guaranteed to be the same as what was passed to `allocFn`.
/// Guaranteed to be >= 1.
/// Guaranteed to be a power of 2.
old_alignment: u29,
@ -57,23 +102,49 @@ pub const Allocator = struct {
/// Guaranteed to be a power of 2.
/// Returned slice's pointer must have this alignment.
new_alignment: u29,
) Error![]u8,
/// 0 indicates the length of the slice returned MUST match `new_byte_count` exactly
/// non-zero means the length of the returned slice must be aligned by `len_align`
/// `new_len` must be aligned by `len_align`
len_align: u29,
) Error![]u8 {
if (old_mem.len == 0) {
const new_mem = try self.callAllocFn(new_byte_count, new_alignment, len_align);
@memset(new_mem.ptr, undefined, new_byte_count);
return new_mem;
}
/// This function deallocates memory. It must succeed.
shrinkFn: fn (
self: *Allocator,
/// Guaranteed to be the same as what was returned from most recent call to
/// `reallocFn` or `shrinkFn`.
old_mem: []u8,
/// Guaranteed to be the same as what was returned from most recent call to
/// `reallocFn` or `shrinkFn`.
old_alignment: u29,
/// Guaranteed to be less than or equal to `old_mem.len`.
new_byte_count: usize,
/// If `new_byte_count == 0` then this is `undefined`, otherwise:
/// Guaranteed to be less than or equal to `old_alignment`.
new_alignment: u29,
) []u8,
if (isAligned(@ptrToInt(old_mem.ptr), new_alignment)) {
if (new_byte_count <= old_mem.len) {
const shrunk_len = self.shrinkBytes(old_mem, new_byte_count, len_align);
if (shrunk_len < old_mem.len) {
@memset(old_mem.ptr + shrunk_len, undefined, old_mem.len - shrunk_len);
}
return old_mem.ptr[0..shrunk_len];
}
if (self.callResizeFn(old_mem, new_byte_count, len_align)) |resized_len| {
assert(resized_len >= new_byte_count);
@memset(old_mem.ptr + new_byte_count, undefined, resized_len - new_byte_count);
return old_mem.ptr[0..resized_len];
} else |_| { }
}
if (new_byte_count <= old_mem.len and new_alignment <= old_alignment) {
return error.OutOfMemory;
}
return self.moveBytes(old_mem, new_byte_count, new_alignment, len_align);
}
/// Move the given memory to a new location in the given allocator to accomodate a new
/// size and alignment.
fn moveBytes(self: *Allocator, old_mem: []u8, new_len: usize, new_alignment: u29, len_align: u29) Error![]u8 {
assert(old_mem.len > 0);
assert(new_len > 0);
const new_mem = try self.callAllocFn(new_len, new_alignment, len_align);
@memcpy(new_mem.ptr, old_mem.ptr, std.math.min(new_len, old_mem.len));
// DISABLED TO AVOID BUGS IN TRANSLATE C
//@memset(old_mem.ptr, undefined, old_mem.len);
_ = self.shrinkBytes(old_mem, 0, 0);
return new_mem;
}
/// Returns a pointer to undefined memory.
/// Call `destroy` with the result to free the memory.
@ -89,8 +160,7 @@ pub const Allocator = struct {
const T = @TypeOf(ptr).Child;
if (@sizeOf(T) == 0) return;
const non_const_ptr = @intToPtr([*]u8, @ptrToInt(ptr));
const shrink_result = self.shrinkFn(self, non_const_ptr[0..@sizeOf(T)], @alignOf(T), 0, 1);
assert(shrink_result.len == 0);
_ = self.shrinkBytes(non_const_ptr[0..@sizeOf(T)], 0, 0);
}
/// Allocates an array of `n` items of type `T` and sets all the
@ -150,9 +220,21 @@ pub const Allocator = struct {
/// null means naturally aligned
comptime alignment: ?u29,
n: usize,
) Error![]align(alignment orelse @alignOf(T)) T {
return self.alignedAlloc2(T, alignment, n, .exact);
}
const Exact = enum {exact,atLeast};
pub fn alignedAlloc2(
self: *Allocator,
comptime T: type,
/// null means naturally aligned
comptime alignment: ?u29,
n: usize,
exact: Exact,
) Error![]align(alignment orelse @alignOf(T)) T {
const a = if (alignment) |a| blk: {
if (a == @alignOf(T)) return alignedAlloc(self, T, null, n);
if (a == @alignOf(T)) return alignedAlloc2(self, T, null, n, exact);
break :blk a;
} else @alignOf(T);
@ -161,15 +243,16 @@ pub const Allocator = struct {
}
const byte_count = math.mul(usize, @sizeOf(T), n) catch return Error.OutOfMemory;
const byte_slice = try self.reallocFn(self, &[0]u8{}, undefined, byte_count, a);
assert(byte_slice.len == byte_count);
// TODO The `if (alignment == null)` blocks are workarounds for zig not being able to
// access certain type information about T without creating a circular dependency in async
// functions that heap-allocate their own frame with @Frame(func).
const sizeOfT = if (alignment == null) @intCast(u29, @divExact(byte_count, n)) else @sizeOf(T);
const byte_slice = try self.callAllocFn(byte_count, a, if (exact == .exact) @as(u29, 0) else sizeOfT);
assert(if (exact == .exact) byte_slice.len == byte_count else byte_slice.len >= byte_count);
@memset(byte_slice.ptr, undefined, byte_slice.len);
if (alignment == null) {
// TODO This is a workaround for zig not being able to successfully do
// @bytesToSlice(T, @alignCast(a, byte_slice)) without resolving alignment of T,
// which causes a circular dependency in async functions which try to heap-allocate
// their own frame with @Frame(func).
return @intToPtr([*]T, @ptrToInt(byte_slice.ptr))[0..n];
// This if block is a workaround (see comment above)
return @intToPtr([*]T, @ptrToInt(byte_slice.ptr))[0..@divExact(byte_slice.len, @sizeOf(T))];
} else {
return mem.bytesAsSlice(T, @alignCast(a, byte_slice));
}
@ -190,7 +273,15 @@ pub const Allocator = struct {
break :t Error![]align(Slice.alignment) Slice.child;
} {
const old_alignment = @typeInfo(@TypeOf(old_mem)).Pointer.alignment;
return self.alignedRealloc(old_mem, old_alignment, new_n);
return self.alignedRealloc2(old_mem, old_alignment, new_n, .exact);
}
pub fn reallocAtLeast(self: *Allocator, old_mem: var, new_n: usize) t: {
const Slice = @typeInfo(@TypeOf(old_mem)).Pointer;
break :t Error![]align(Slice.alignment) Slice.child;
} {
const old_alignment = @typeInfo(@TypeOf(old_mem)).Pointer.alignment;
return self.alignedRealloc2(old_mem, old_alignment, new_n, .atLeast);
}
/// This is the same as `realloc`, except caller may additionally request
@ -201,11 +292,24 @@ pub const Allocator = struct {
old_mem: var,
comptime new_alignment: u29,
new_n: usize,
) Error![]align(new_alignment) @typeInfo(@TypeOf(old_mem)).Pointer.child {
return self.alignedRealloc2(old_mem, new_alignment, new_n, .exact);
}
/// This is the same as `realloc`, except caller may additionally request
/// a new alignment, which can be larger, smaller, or the same as the old
/// allocation.
pub fn alignedRealloc2(
self: *Allocator,
old_mem: var,
comptime new_alignment: u29,
new_n: usize,
exact: Exact,
) Error![]align(new_alignment) @typeInfo(@TypeOf(old_mem)).Pointer.child {
const Slice = @typeInfo(@TypeOf(old_mem)).Pointer;
const T = Slice.child;
if (old_mem.len == 0) {
return self.alignedAlloc(T, new_alignment, new_n);
return self.alignedAlloc2(T, new_alignment, new_n, exact);
}
if (new_n == 0) {
self.free(old_mem);
@ -215,12 +319,9 @@ pub const Allocator = struct {
const old_byte_slice = mem.sliceAsBytes(old_mem);
const byte_count = math.mul(usize, @sizeOf(T), new_n) catch return Error.OutOfMemory;
// Note: can't set shrunk memory to undefined as memory shouldn't be modified on realloc failure
const byte_slice = try self.reallocFn(self, old_byte_slice, Slice.alignment, byte_count, new_alignment);
assert(byte_slice.len == byte_count);
if (new_n > old_mem.len) {
@memset(byte_slice.ptr + old_byte_slice.len, undefined, byte_slice.len - old_byte_slice.len);
}
return mem.bytesAsSlice(T, @alignCast(new_alignment, byte_slice));
const new_byte_slice = try self.reallocBytes(old_byte_slice, Slice.alignment, byte_count, new_alignment,
if (exact == .exact) @as(u29, 0) else @sizeOf(T));
return mem.bytesAsSlice(T, @alignCast(new_alignment, new_byte_slice));
}
/// Prefer calling realloc to shrink if you can tolerate failure, such as
@ -248,12 +349,9 @@ pub const Allocator = struct {
const Slice = @typeInfo(@TypeOf(old_mem)).Pointer;
const T = Slice.child;
if (new_n == 0) {
self.free(old_mem);
return old_mem[0..0];
}
assert(new_n <= old_mem.len);
if (new_n == old_mem.len)
return old_mem;
assert(new_n < old_mem.len);
assert(new_alignment <= Slice.alignment);
// Here we skip the overflow checking on the multiplication because
@ -262,9 +360,8 @@ pub const Allocator = struct {
const old_byte_slice = mem.sliceAsBytes(old_mem);
@memset(old_byte_slice.ptr + byte_count, undefined, old_byte_slice.len - byte_count);
const byte_slice = self.shrinkFn(self, old_byte_slice, Slice.alignment, byte_count, new_alignment);
assert(byte_slice.len == byte_count);
return mem.bytesAsSlice(T, @alignCast(new_alignment, byte_slice));
_ = self.shrinkBytes(old_byte_slice, byte_count, 0);
return old_mem[0..new_n];
}
/// Free an array allocated with `alloc`. To free a single item,
@ -276,8 +373,7 @@ pub const Allocator = struct {
if (bytes_len == 0) return;
const non_const_ptr = @intToPtr([*]u8, @ptrToInt(bytes.ptr));
@memset(non_const_ptr, undefined, bytes_len);
const shrink_result = self.shrinkFn(self, non_const_ptr[0..bytes_len], Slice.alignment, 0, 1);
assert(shrink_result.len == 0);
_ = self.shrinkBytes(non_const_ptr[0..bytes_len], 0, 0);
}
/// Copies `m` to newly allocated memory. Caller owns the memory.
@ -296,15 +392,106 @@ pub const Allocator = struct {
}
};
var failAllocator = Allocator{
.reallocFn = failAllocatorRealloc,
.shrinkFn = failAllocatorShrink,
};
fn failAllocatorRealloc(self: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
return error.OutOfMemory;
/// Given a pointer to an allocator, return the *Allocator for it. `allocatorStatePtr` can
/// either be a `*Allocator`, in which case it is returned as-is, otherwise, the address of
/// the `allocator` field is returned.
pub fn getAllocatorPtr(allocatorStatePtr: var) *Allocator {
// allocator must be a pointer or else this function will return a copy of the allocator which
// is not what this is for
const T = @TypeOf(allocatorStatePtr);
switch (@typeInfo(T)) {
.Pointer => {},
else => @compileError("getAllocatorPtr expects a pointer to an allocator but got: " ++ @typeName(T)),
}
if (T == *Allocator)
return allocatorStatePtr;
return &allocatorStatePtr.allocator;
}
fn failAllocatorShrink(self: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
@panic("failAllocatorShrink should never be called because it cannot allocate");
/// Detects and asserts if the std.mem.Allocator interface is violated
pub fn SanityAllocator(comptime T: type) type { return struct {
const Self = @This();
allocator: Allocator,
underlying_allocator: T,
pub fn init(allocator: T) @This() {
return .{
.allocator = .{
.allocFn = alloc,
.resizeFn = resize,
},
.underlying_allocator = allocator,
};
}
fn getUnderlyingAllocatorPtr(self: *@This()) *Allocator {
if (T == *Allocator) return self.underlying_allocator;
return getAllocatorPtr(&self.underlying_allocator);
}
pub fn alloc(allocator: *Allocator, n: usize, ptr_align: u29, len_align: u29) Allocator.Error![]u8 {
assert(n > 0);
assert(mem.isValidAlign(ptr_align));
if (len_align != 0) {
assert(mem.isAlignedAnyAlign(n, len_align));
assert(n >= len_align);
}
const self = @fieldParentPtr(@This(), "allocator", allocator);
const result = try self.getUnderlyingAllocatorPtr().callAllocFn(n, ptr_align, len_align);
if (len_align == 0) {
assert(result.len == n);
} else {
assert(result.len >= n);
assert(mem.isAlignedAnyAlign(result.len, len_align));
}
return result;
}
pub fn resize(allocator: *Allocator, buf: []u8, new_len: usize, len_align: u29) Allocator.Error!usize {
assert(buf.len > 0);
if (len_align != 0) {
assert(mem.isAlignedAnyAlign(new_len, len_align));
assert(new_len >= len_align);
}
const self = @fieldParentPtr(@This(), "allocator", allocator);
const result = try self.getUnderlyingAllocatorPtr().callResizeFn(buf, new_len, len_align);
if (len_align == 0) {
assert(result == new_len);
} else {
assert(result >= new_len);
assert(mem.isAlignedAnyAlign(result, len_align));
}
return result;
}
pub usingnamespace if (T == *Allocator or !@hasDecl(T, "reset")) struct {} else struct {
pub fn reset(self: *Self) void {
self.underlying_allocator.reset();
}
};
};}
pub fn sanityWrap(allocator: var) SanityAllocator(@TypeOf(allocator)) {
return SanityAllocator(@TypeOf(allocator)).init(allocator);
}
/// An allocator helper function. Adjusts an allocation length satisfy `len_align`.
/// `full_len` should be the full capacity of the allocation which may be greater
/// than the `len` that was requsted. This function should only be used by allocators
/// that are unaffected by `len_align`.
pub fn alignAllocLen(full_len: usize, alloc_len: usize, len_align: u29) usize {
assert(alloc_len > 0);
assert(alloc_len >= len_align);
assert(full_len >= alloc_len);
if (len_align == 0)
return alloc_len;
const adjusted = alignBackwardAnyAlign(full_len, len_align);
assert(adjusted >= alloc_len);
return adjusted;
}
var failAllocator = Allocator{
.allocFn = failAllocatorAlloc,
.resizeFn = Allocator.noResize,
};
fn failAllocatorAlloc(self: *Allocator, n: usize, alignment: u29, len_align: u29) Allocator.Error![]u8 {
return error.OutOfMemory;
}
test "mem.Allocator basics" {
@ -2190,6 +2377,13 @@ test "alignForward" {
testing.expect(alignForward(17, 8) == 24);
}
pub fn alignBackwardAnyAlign(i: usize, alignment: usize) usize {
if (@popCount(usize, alignment) == 1)
return alignBackward(i, alignment);
assert(alignment != 0);
return i - @mod(i, alignment);
}
/// Round an address up to the previous aligned address
/// The alignment must be a power of 2 and greater than 0.
pub fn alignBackward(addr: usize, alignment: usize) usize {
@ -2206,6 +2400,19 @@ pub fn alignBackwardGeneric(comptime T: type, addr: T, alignment: T) T {
return addr & ~(alignment - 1);
}
/// Returns whether `alignment` is a valid alignment, meaning it is
/// a positive power of 2.
pub fn isValidAlign(alignment: u29) bool {
return @popCount(u29, alignment) == 1;
}
pub fn isAlignedAnyAlign(i: usize, alignment: usize) bool {
if (@popCount(usize, alignment) == 1)
return isAligned(i, alignment);
assert(alignment != 0);
return 0 == @mod(i, alignment);
}
/// Given an address and an alignment, return true if the address is a multiple of the alignment
/// The alignment must be a power of 2 and greater than 0.
pub fn isAligned(addr: usize, alignment: usize) bool {

1
lib/std/os/windows/bits.zig
View File

@ -593,6 +593,7 @@ pub const FILE_CURRENT = 1;
pub const FILE_END = 2;
pub const HEAP_CREATE_ENABLE_EXECUTE = 0x00040000;
pub const HEAP_REALLOC_IN_PLACE_ONLY = 0x00000010;
pub const HEAP_GENERATE_EXCEPTIONS = 0x00000004;
pub const HEAP_NO_SERIALIZE = 0x00000001;

2
lib/std/testing.zig
View File

@ -11,7 +11,7 @@ pub var allocator_instance = LeakCountAllocator.init(&base_allocator_instance.al
pub const failing_allocator = &failing_allocator_instance.allocator;
pub var failing_allocator_instance = FailingAllocator.init(&base_allocator_instance.allocator, 0);
pub var base_allocator_instance = std.heap.ThreadSafeFixedBufferAllocator.init(allocator_mem[0..]);
pub var base_allocator_instance = std.mem.sanityWrap(std.heap.ThreadSafeFixedBufferAllocator.init(allocator_mem[0..]));
var allocator_mem: [2 * 1024 * 1024]u8 = undefined;
/// This function is intended to be used only in tests. It prints diagnostics to stderr

41
lib/std/testing/failing_allocator.zig
View File

@ -39,43 +39,38 @@ pub const FailingAllocator = struct {
.allocations = 0,
.deallocations = 0,
.allocator = mem.Allocator{
.reallocFn = realloc,
.shrinkFn = shrink,
.allocFn = alloc,
.resizeFn = resize,
},
};
}
fn realloc(allocator: *mem.Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
fn alloc(allocator: *std.mem.Allocator, len: usize, ptr_align: u29, len_align: u29) error{OutOfMemory}![]u8 {
const self = @fieldParentPtr(FailingAllocator, "allocator", allocator);
if (self.index == self.fail_index) {
return error.OutOfMemory;
}
const result = try self.internal_allocator.reallocFn(
self.internal_allocator,
old_mem,
old_align,
new_size,
new_align,
);
if (new_size < old_mem.len) {
self.freed_bytes += old_mem.len - new_size;
if (new_size == 0)
self.deallocations += 1;
} else if (new_size > old_mem.len) {
self.allocated_bytes += new_size - old_mem.len;
if (old_mem.len == 0)
self.allocations += 1;
}
const result = try self.internal_allocator.callAllocFn(len, ptr_align, len_align);
self.allocated_bytes += result.len;
self.allocations += 1;
self.index += 1;
return result;
}
fn shrink(allocator: *mem.Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
fn resize(allocator: *std.mem.Allocator, old_mem: []u8, new_len: usize, len_align: u29) error{OutOfMemory}!usize {
const self = @fieldParentPtr(FailingAllocator, "allocator", allocator);
const r = self.internal_allocator.shrinkFn(self.internal_allocator, old_mem, old_align, new_size, new_align);
self.freed_bytes += old_mem.len - r.len;
if (new_size == 0)
const r = self.internal_allocator.callResizeFn(old_mem, new_len, len_align) catch |e| {
std.debug.assert(new_len > old_mem.len);
return e;
};
if (new_len == 0) {
self.deallocations += 1;
self.freed_bytes += old_mem.len;
} else if (r < old_mem.len) {
self.freed_bytes += old_mem.len - r;
} else {
self.allocated_bytes += r - old_mem.len;
}
return r;
}
};

21
lib/std/testing/leak_count_allocator.zig
View File

@ -14,23 +14,21 @@ pub const LeakCountAllocator = struct {
return .{
.count = 0,
.allocator = .{
.reallocFn = realloc,
.shrinkFn = shrink,
.allocFn = alloc,
.resizeFn = resize,
},
.internal_allocator = allocator,
};
}
fn realloc(allocator: *std.mem.Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
fn alloc(allocator: *std.mem.Allocator, len: usize, ptr_align: u29, len_align: u29) error{OutOfMemory}![]u8 {
const self = @fieldParentPtr(LeakCountAllocator, "allocator", allocator);
var data = try self.internal_allocator.reallocFn(self.internal_allocator, old_mem, old_align, new_size, new_align);
if (old_mem.len == 0) {
self.count += 1;
}
return data;
const ptr = try self.internal_allocator.callAllocFn(len, ptr_align, len_align);
self.count += 1;
return ptr;
}
fn shrink(allocator: *std.mem.Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
fn resize(allocator: *std.mem.Allocator, old_mem: []u8, new_size: usize, len_align: u29) error{OutOfMemory}!usize {
const self = @fieldParentPtr(LeakCountAllocator, "allocator", allocator);
if (new_size == 0) {
if (self.count == 0) {
@ -38,7 +36,10 @@ pub const LeakCountAllocator = struct {
}
self.count -= 1;
}
return self.internal_allocator.shrinkFn(self.internal_allocator, old_mem, old_align, new_size, new_align);
return self.internal_allocator.callResizeFn(old_mem, new_size, len_align) catch |e| {
std.debug.assert(new_size > old_mem.len);
return e;
};
}
pub fn validate(self: LeakCountAllocator) !void {