authorgravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2023-04-28 11:43:57-07:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2023-04-28 11:43:57-07:00
logfd6200eda6d4fe19c34a59430a88a9ce38d6d7a4
treee409cf30751281f3e8ebe70fbe67400aa4a4cdea
parent011bc59e8aa4b62a286e4dd6e92371af5dac8b9f
parent15dafd16e65a8cd8ea434f0b4783f08875254cd4
signaturebadge-question-mark Signed by PGP key 4AEE18F83AFDEB23

Merge pull request #15431 from kcbanner/fix_decl_value_arena

sema: Rework Decl.value_arena to fix another memory corruption issue

3 files changed, 98 insertions(+), 34 deletions(-)

src/Module.zig+59-14
......@@ -411,6 +411,46 @@ pub const WipCaptureScope = struct {
411411 }
412412};
413413
414const ValueArena = struct {
415 state: std.heap.ArenaAllocator.State,
416 state_acquired: ?*std.heap.ArenaAllocator.State = null,
417
418 /// If this ValueArena replaced an existing one during re-analysis, this is the previous instance
419 prev: ?*ValueArena = null,
420
421 /// Returns an allocator backed by either promoting `state`, or by the existing ArenaAllocator
422 /// that has already promoted `state`. `out_arena_allocator` provides storage for the initial promotion,
423 /// and must live until the matching call to release().
424 pub fn acquire(self: *ValueArena, child_allocator: Allocator, out_arena_allocator: *std.heap.ArenaAllocator) Allocator {
425 if (self.state_acquired) |state_acquired| {
426 return @fieldParentPtr(std.heap.ArenaAllocator, "state", state_acquired).allocator();
427 }
428
429 out_arena_allocator.* = self.state.promote(child_allocator);
430 self.state_acquired = &out_arena_allocator.state;
431 return out_arena_allocator.allocator();
432 }
433
434 /// Releases the allocator acquired by `acquire. `arena_allocator` must match the one passed to `acquire`.
435 pub fn release(self: *ValueArena, arena_allocator: *std.heap.ArenaAllocator) void {
436 if (@fieldParentPtr(std.heap.ArenaAllocator, "state", self.state_acquired.?) == arena_allocator) {
437 self.state = self.state_acquired.?.*;
438 self.state_acquired = null;
439 }
440 }
441
442 pub fn deinit(self: ValueArena, child_allocator: Allocator) void {
443 assert(self.state_acquired == null);
444
445 const prev = self.prev;
446 self.state.promote(child_allocator).deinit();
447
448 if (prev) |p| {
449 p.deinit(child_allocator);
450 }
451 }
452};
453
414454pub const Decl = struct {
415455 /// Allocated with Module's allocator; outlives the ZIR code.
416456 name: [*:0]const u8,
......@@ -429,7 +469,7 @@ pub const Decl = struct {
429469 @"addrspace": std.builtin.AddressSpace,
430470 /// The memory for ty, val, align, linksection, and captures.
431471 /// If this is `null` then there is no memory management needed.
432 value_arena: ?*std.heap.ArenaAllocator.State = null,
472 value_arena: ?*ValueArena = null,
433473 /// The direct parent namespace of the Decl.
434474 /// Reference to externally owned memory.
435475 /// In the case of the Decl corresponding to a file, this is
......@@ -607,7 +647,7 @@ pub const Decl = struct {
607647 variable.deinit(gpa);
608648 gpa.destroy(variable);
609649 }
610 if (decl.value_arena) |arena_state| {
650 if (decl.value_arena) |value_arena| {
611651 if (decl.owns_tv) {
612652 if (decl.val.castTag(.str_lit)) |str_lit| {
613653 mod.string_literal_table.getPtrContext(str_lit.data, .{
......@@ -615,7 +655,7 @@ pub const Decl = struct {
615655 }).?.* = .none;
616656 }
617657 }
618 arena_state.promote(gpa).deinit();
658 value_arena.deinit(gpa);
619659 decl.value_arena = null;
620660 decl.has_tv = false;
621661 decl.owns_tv = false;
......@@ -624,9 +664,9 @@ pub const Decl = struct {
624664
625665 pub fn finalizeNewArena(decl: *Decl, arena: *std.heap.ArenaAllocator) !void {
626666 assert(decl.value_arena == null);
627 const arena_state = try arena.allocator().create(std.heap.ArenaAllocator.State);
628 arena_state.* = arena.state;
629 decl.value_arena = arena_state;
667 const value_arena = try arena.allocator().create(ValueArena);
668 value_arena.* = .{ .state = arena.state };
669 decl.value_arena = value_arena;
630670 }
631671
632672 /// This name is relative to the containing namespace of the decl.
......@@ -4537,15 +4577,20 @@ fn semaDecl(mod: *Module, decl_index: Decl.Index) !bool {
45374577 // We need the memory for the Type to go into the arena for the Decl
45384578 var decl_arena = std.heap.ArenaAllocator.init(gpa);
45394579 const decl_arena_allocator = decl_arena.allocator();
4540
4541 const decl_arena_state = blk: {
4580 const decl_value_arena = blk: {
45424581 errdefer decl_arena.deinit();
4543 const s = try decl_arena_allocator.create(std.heap.ArenaAllocator.State);
4582 const s = try decl_arena_allocator.create(ValueArena);
4583 s.* = .{ .state = undefined };
45444584 break :blk s;
45454585 };
45464586 defer {
4547 decl_arena_state.* = decl_arena.state;
4548 decl.value_arena = decl_arena_state;
4587 if (decl.value_arena) |value_arena| {
4588 assert(value_arena.state_acquired == null);
4589 decl_value_arena.prev = value_arena;
4590 }
4591
4592 decl_value_arena.state = decl_arena.state;
4593 decl.value_arena = decl_value_arena;
45494594 }
45504595
45514596 var analysis_arena = std.heap.ArenaAllocator.init(gpa);
......@@ -5493,9 +5538,9 @@ pub fn analyzeFnBody(mod: *Module, func: *Fn, arena: Allocator) SemaError!Air {
54935538 const decl = mod.declPtr(decl_index);
54945539
54955540 // Use the Decl's arena for captured values.
5496 var decl_arena = decl.value_arena.?.promote(gpa);
5497 defer decl.value_arena.?.* = decl_arena.state;
5498 const decl_arena_allocator = decl_arena.allocator();
5541 var decl_arena: std.heap.ArenaAllocator = undefined;
5542 const decl_arena_allocator = decl.value_arena.?.acquire(gpa, &decl_arena);
5543 defer decl.value_arena.?.release(&decl_arena);
54995544
55005545 var sema: Sema = .{
55015546 .mod = mod,
src/Sema.zig+18-20
......@@ -2856,9 +2856,9 @@ fn zirEnumDecl(
28562856 const decl_val = try sema.analyzeDeclVal(block, src, new_decl_index);
28572857 done = true;
28582858
2859 var decl_arena = new_decl.value_arena.?.promote(gpa);
2860 defer new_decl.value_arena.?.* = decl_arena.state;
2861 const decl_arena_allocator = decl_arena.allocator();
2859 var decl_arena: std.heap.ArenaAllocator = undefined;
2860 const decl_arena_allocator = new_decl.value_arena.?.acquire(gpa, &decl_arena);
2861 defer new_decl.value_arena.?.release(&decl_arena);
28622862
28632863 extra_index = try mod.scanNamespace(&enum_obj.namespace, extra_index, decls_len, new_decl);
28642864
......@@ -26999,13 +26999,12 @@ const ComptimePtrMutationKit = struct {
2699926999
2700027000 fn beginArena(self: *ComptimePtrMutationKit, mod: *Module) Allocator {
2700127001 const decl = mod.declPtr(self.decl_ref_mut.decl_index);
27002 self.decl_arena = decl.value_arena.?.promote(mod.gpa);
27003 return self.decl_arena.allocator();
27002 return decl.value_arena.?.acquire(mod.gpa, &self.decl_arena);
2700427003 }
2700527004
2700627005 fn finishArena(self: *ComptimePtrMutationKit, mod: *Module) void {
2700727006 const decl = mod.declPtr(self.decl_ref_mut.decl_index);
27008 decl.value_arena.?.* = self.decl_arena.state;
27007 decl.value_arena.?.release(&self.decl_arena);
2700927008 self.decl_arena = undefined;
2701027009 }
2701127010};
......@@ -27036,6 +27035,7 @@ fn beginComptimePtrMutation(
2703627035 .elem_ptr => {
2703727036 const elem_ptr = ptr_val.castTag(.elem_ptr).?.data;
2703827037 var parent = try sema.beginComptimePtrMutation(block, src, elem_ptr.array_ptr, elem_ptr.elem_ty);
27038
2703927039 switch (parent.pointee) {
2704027040 .direct => |val_ptr| switch (parent.ty.zigTypeTag()) {
2704127041 .Array, .Vector => {
......@@ -30653,10 +30653,9 @@ fn resolveStructLayout(sema: *Sema, ty: Type) CompileError!void {
3065330653 try sema.perm_arena.alloc(u32, struct_obj.fields.count())
3065430654 else blk: {
3065530655 const decl = sema.mod.declPtr(struct_obj.owner_decl);
30656 var decl_arena = decl.value_arena.?.promote(sema.mod.gpa);
30657 defer decl.value_arena.?.* = decl_arena.state;
30658 const decl_arena_allocator = decl_arena.allocator();
30659
30656 var decl_arena: std.heap.ArenaAllocator = undefined;
30657 const decl_arena_allocator = decl.value_arena.?.acquire(sema.mod.gpa, &decl_arena);
30658 defer decl.value_arena.?.release(&decl_arena);
3066030659 break :blk try decl_arena_allocator.alloc(u32, struct_obj.fields.count());
3066130660 };
3066230661
......@@ -30700,9 +30699,9 @@ fn semaBackingIntType(mod: *Module, struct_obj: *Module.Struct) CompileError!voi
3070030699
3070130700 const decl_index = struct_obj.owner_decl;
3070230701 const decl = mod.declPtr(decl_index);
30703 var decl_arena = decl.value_arena.?.promote(gpa);
30704 defer decl.value_arena.?.* = decl_arena.state;
30705 const decl_arena_allocator = decl_arena.allocator();
30702 var decl_arena: std.heap.ArenaAllocator = undefined;
30703 const decl_arena_allocator = decl.value_arena.?.acquire(gpa, &decl_arena);
30704 defer decl.value_arena.?.release(&decl_arena);
3070630705
3070730706 const zir = struct_obj.namespace.file_scope.zir;
3070830707 const extended = zir.instructions.items(.data)[struct_obj.zir_index].extended;
......@@ -31394,9 +31393,9 @@ fn semaStructFields(mod: *Module, struct_obj: *Module.Struct) CompileError!void
3139431393 }
3139531394
3139631395 const decl = mod.declPtr(decl_index);
31397 var decl_arena = decl.value_arena.?.promote(gpa);
31398 defer decl.value_arena.?.* = decl_arena.state;
31399 const decl_arena_allocator = decl_arena.allocator();
31396 var decl_arena: std.heap.ArenaAllocator = undefined;
31397 const decl_arena_allocator = decl.value_arena.?.acquire(gpa, &decl_arena);
31398 defer decl.value_arena.?.release(&decl_arena);
3140031399
3140131400 var analysis_arena = std.heap.ArenaAllocator.init(gpa);
3140231401 defer analysis_arena.deinit();
......@@ -31734,10 +31733,9 @@ fn semaUnionFields(mod: *Module, union_obj: *Module.Union) CompileError!void {
3173431733 extra_index += body.len;
3173531734
3173631735 const decl = mod.declPtr(decl_index);
31737
31738 var decl_arena = decl.value_arena.?.promote(gpa);
31739 defer decl.value_arena.?.* = decl_arena.state;
31740 const decl_arena_allocator = decl_arena.allocator();
31736 var decl_arena: std.heap.ArenaAllocator = undefined;
31737 const decl_arena_allocator = decl.value_arena.?.acquire(gpa, &decl_arena);
31738 defer decl.value_arena.?.release(&decl_arena);
3174131739
3174231740 var analysis_arena = std.heap.ArenaAllocator.init(gpa);
3174331741 defer analysis_arena.deinit();
test/cases/decl_value_arena.zig created+21
......@@ -0,0 +1,21 @@
1pub const Protocols: struct {
2 list: *const fn(*Connection) void = undefined,
3 handShake: type = struct {
4 const stepStart: u8 = 0;
5 },
6} = .{};
7
8pub const Connection = struct {
9 streamBuffer: [0]u8 = undefined,
10 __lastReceivedPackets: [0]u8 = undefined,
11
12 handShakeState: u8 = Protocols.handShake.stepStart,
13};
14
15pub fn main() void {
16 var conn: Connection = undefined;
17 _ = conn;
18}
19
20// run
21//