authorgravatar for contact@fengb.meBenjamin Feng <contact@fengb.me> 2019-11-27 21:19:08-06:00
committergravatar for contact@fengb.meBenjamin Feng <contact@fengb.me> 2019-12-02 09:59:20-06:00
logeb1628b03325787504d46bfaef3046fef5ed1d59
tree382c23113c76947b752b533ebfe7281b0d1f9ec3
parenteff926b4545fea9f87559d2e1d7372d6cbeba780

Initialize memory segments

1 files changed, 37 insertions(+), 10 deletions(-)

lib/std/heap.zig+37-10
...@@ -253,7 +253,7 @@ extern fn @"llvm.wasm.memory.size.i32"(u32) u32;...@@ -253,7 +253,7 @@ extern fn @"llvm.wasm.memory.size.i32"(u32) u32;
253extern fn @"llvm.wasm.memory.grow.i32"(u32, u32) i32;253extern fn @"llvm.wasm.memory.grow.i32"(u32, u32) i32;
254254
255test "" {255test "" {
256 _ = WasmPageAllocator.alloc;256 _ = WasmPageAllocator.realloc;
257}257}
258258
259const WasmPageAllocator = struct {259const WasmPageAllocator = struct {
...@@ -261,12 +261,24 @@ const WasmPageAllocator = struct {...@@ -261,12 +261,24 @@ const WasmPageAllocator = struct {
261 offset: usize = 0,261 offset: usize = 0,
262 data: []u8 = &[_]u8{},262 data: []u8 = &[_]u8{},
263263
264 fn alloc(self: FreeBlock, num_pages: usize) ?[]u8 {264 fn initData(self: *FreeBlock, data: []u8) void {
265 std.mem.set(u8, data, 0);
266 self.data = data;
267 }
268
269 fn totalPages(self: FreeBlock) usize {
270 return self.data.len * @typeInfo(usize).Int.bits;
271 }
272
273 fn alloc(self: *FreeBlock, num_pages: usize) ?[]u8 {
265 return null;274 return null;
266 }275 }
276
277 fn reclaim(self: *FreeBlock, start_page: usize, end_page: usize) void {}
267 };278 };
268 var base = FreeBlock{};279
269 var additional = FreeBlock{};280 var conventional = FreeBlock{};
281 var extended = FreeBlock{};
270282
271 fn nPages(memsize: usize) usize {283 fn nPages(memsize: usize) usize {
272 return std.mem.alignForward(memsize, std.mem.page_size) / std.mem.page_size;284 return std.mem.alignForward(memsize, std.mem.page_size) / std.mem.page_size;
...@@ -278,7 +290,7 @@ const WasmPageAllocator = struct {...@@ -278,7 +290,7 @@ const WasmPageAllocator = struct {
278 }290 }
279291
280 const n_pages = nPages(n);292 const n_pages = nPages(n);
281 return base.alloc(n_pages) orelse additional.alloc(n_pages) orelse {293 return conventional.alloc(n_pages) orelse extended.alloc(n_pages) orelse {
282 const prev_page_count = @"llvm.wasm.memory.grow.i32"(0, @intCast(u32, n_pages));294 const prev_page_count = @"llvm.wasm.memory.grow.i32"(0, @intCast(u32, n_pages));
283 if (prev_page_count < 0) {295 if (prev_page_count < 0) {
284 return error.OutOfMemory;296 return error.OutOfMemory;
...@@ -305,13 +317,28 @@ const WasmPageAllocator = struct {...@@ -305,13 +317,28 @@ const WasmPageAllocator = struct {
305 }317 }
306318
307 pub fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {319 pub fn shrink(allocator: *Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
308 var shrinkage = nPages(old_mem.len) - nPages(new_size);320 const free_start = nPages(@ptrToInt(old_mem.ptr) + new_size);
309 if (shrinkage > 0) {321 var free_end = nPages(@ptrToInt(old_mem.ptr) + old_mem.len);
310 const success = base.recycle(old_mem[new_size..old_mem.len]);322
311 if (!success) {323 if (free_end > free_start) {
312 std.debug.assert(additional.recycle(old_mem[new_size..old_mem.len]));324 if (conventional.data.len == 0) {
325 conventional.initData(__heap_base[0..@intCast(usize, @"llvm.wasm.memory.size.i32"(0) * std.mem.page_size)]);
326 }
327
328 if (free_start < conventional.totalPages()) {
329 conventional.reclaim(free_start, free_end);
330 } else {
331 if (extended.data.len == 0) {
332 extended.offset = conventional.totalPages();
333
334 // Steal the last page from the memory currently being reclaimed
335 free_end -= 1;
336 extended.initData(@intToPtr([*]u8, free_end)[0..std.mem.page_size]);
337 }
338 conventional.reclaim(free_start, free_end);
313 }339 }
314 }340 }
341
315 return old_mem[0..new_size];342 return old_mem[0..new_size];
316 }343 }
317};344};