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Standardize around bigger slices

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This commit is contained in:
Benjamin Feng 2019-12-05 18:28:32 -06:00
parent 7d1c4fe4dc
commit 694616adb5
1 changed files with 14 additions and 23 deletions
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37
lib/std/heap.zig
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@ -246,16 +246,12 @@ const PageAllocator = struct {
}
};
extern const __heap_base: [*]u8;
// TODO Exposed LLVM intrinsics is a bug
// See: https://github.com/ziglang/zig/issues/2291
extern fn @"llvm.wasm.memory.size.i32"(u32) u32;
extern fn @"llvm.wasm.memory.grow.i32"(u32, u32) i32;
const WasmPageAllocator = struct {
// TODO: figure out why __heap_base cannot be found
var heap_base_wannabe align(16) = [_]u8{0} ** 256;
const PageStatus = enum(u1) {
used = 0,
free = 1,
@ -264,24 +260,24 @@ const WasmPageAllocator = struct {
};
const FreeBlock = struct {
bytes: []align(16) u8,
data: []u128,
const Io = std.packed_int_array.PackedIntIo(u1, .Little);
fn totalPages(self: FreeBlock) usize {
return self.bytes.len * 8;
return self.data.len * 8;
}
fn getBit(self: *FreeBlock, idx: usize) PageStatus {
fn getBit(self: FreeBlock, idx: usize) PageStatus {
const bit_offset = 0;
return @intToEnum(PageStatus, Io.get(self.bytes, idx, bit_offset));
return @intToEnum(PageStatus, Io.get(@sliceToBytes(self.data), idx, bit_offset));
}
fn setBits(self: *FreeBlock, start_idx: usize, len: usize, val: PageStatus) void {
fn setBits(self: FreeBlock, start_idx: usize, len: usize, val: PageStatus) void {
const bit_offset = 0;
var i: usize = 0;
while (i < len) : (i += 1) {
Io.set(self.bytes, start_idx + i, bit_offset, @enumToInt(val));
Io.set(@sliceToBytes(self.data), start_idx + i, bit_offset, @enumToInt(val));
}
}
@ -294,10 +290,9 @@ const WasmPageAllocator = struct {
// Revisit if this is settled: https://github.com/ziglang/zig/issues/3806
const not_found = std.math.maxInt(usize);
fn useRecycled(self: *FreeBlock, num_pages: usize) usize {
fn useRecycled(self: FreeBlock, num_pages: usize) usize {
@setCold(true);
const segments = @bytesToSlice(u128, self.bytes);
for (segments) |segment, i| {
for (self.data) |segment, i| {
const spills_into_next = @bitCast(i128, segment) < 0;
const has_enough_bits = @popCount(u128, segment) >= num_pages;
@ -319,13 +314,13 @@ const WasmPageAllocator = struct {
return not_found;
}
fn recycle(self: *FreeBlock, start_idx: usize, len: usize) void {
fn recycle(self: FreeBlock, start_idx: usize, len: usize) void {
self.setBits(start_idx, len, .free);
}
};
var conventional = FreeBlock{ .bytes = &[_]u8{} };
var extended = FreeBlock{ .bytes = &[_]u8{} };
const conventional = FreeBlock{ .data = &[_]u128{ 0, 0 } };
var extended = FreeBlock{ .data = &[_]u128{} };
fn extendedOffset() usize {
return conventional.totalPages();
@ -373,15 +368,11 @@ const WasmPageAllocator = struct {
}
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 (conventional.totalPages() == 0) {
//conventional.bytes = __heap_base[0..@intCast(usize, @"llvm.wasm.memory.size.i32"(0) * std.mem.page_size)];
conventional.bytes = heap_base_wannabe[0..];
}
if (free_start < extendedOffset()) {
const clamped_end = std.math.min(extendedOffset(), free_end);
conventional.recycle(free_start, clamped_end - free_start);
@ -393,9 +384,9 @@ const WasmPageAllocator = struct {
// TODO: would it be better if we use the first page instead?
free_end -= 1;
extended.bytes = @intToPtr([*]align(16) u8, free_end * std.mem.page_size)[0..std.mem.page_size];
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(u8, extended.bytes, PageStatus.all_used);
std.mem.set(u128, extended.data, PageStatus.all_used);
}
const clamped_start = std.math.max(extendedOffset(), free_start);
extended.recycle(clamped_start - extendedOffset(), free_end - clamped_start);