authorgravatar for mlugg@mlugg.co.ukMatthew Lugg <mlugg@mlugg.co.uk> 2025-05-03 20:10:42+01:00
committergravatar for noreply@github.comGitHub <noreply@github.com> 2025-05-03 20:10:42+01:00
logf4e9846bca69e20f907384cdad43b86a3aae1fb2
tree82d5ed3d6b07bc84c1b7cf1033b01bf0f14e50bd
parentf83fe2714bd4441610156e1a6017d07409ad6093
parent81277b5487e53d3e96351c2f1b14f437321210cc
signaturebadge-check Signed by PGP key B5690EEEBB952194

Merge pull request #23263 from mlugg/comptime-field-ptr

Sema: fix pointers to comptime fields of comptime-known aggregate pointers

4 files changed, 79 insertions(+), 33 deletions(-)

src/Sema.zig+24-9
......@@ -27997,12 +27997,17 @@ fn structFieldPtrByIndex(
2799727997 const zcu = pt.zcu;
2799827998 const ip = &zcu.intern_pool;
2799927999
28000 if (try sema.resolveDefinedValue(block, src, struct_ptr)) |struct_ptr_val| {
28001 const val = try struct_ptr_val.ptrField(field_index, pt);
28002 return Air.internedToRef(val.toIntern());
28000 const struct_type = zcu.typeToStruct(struct_ty).?;
28001 const field_is_comptime = struct_type.fieldIsComptime(ip, field_index);
28002
28003 // Comptime fields are handled later
28004 if (!field_is_comptime) {
28005 if (try sema.resolveDefinedValue(block, src, struct_ptr)) |struct_ptr_val| {
28006 const val = try struct_ptr_val.ptrField(field_index, pt);
28007 return Air.internedToRef(val.toIntern());
28008 }
2800328009 }
2800428010
28005 const struct_type = zcu.typeToStruct(struct_ty).?;
2800628011 const field_ty = struct_type.field_types.get(ip)[field_index];
2800728012 const struct_ptr_ty = sema.typeOf(struct_ptr);
2800828013 const struct_ptr_ty_info = struct_ptr_ty.ptrInfo(zcu);
......@@ -28022,6 +28027,7 @@ fn structFieldPtrByIndex(
2802228027 try Type.fromInterned(struct_ptr_ty_info.child).abiAlignmentSema(pt);
2802328028
2802428029 if (struct_type.layout == .@"packed") {
28030 assert(!field_is_comptime);
2802528031 switch (struct_ty.packedStructFieldPtrInfo(struct_ptr_ty, field_index, pt)) {
2802628032 .bit_ptr => |packed_offset| {
2802728033 ptr_ty_data.flags.alignment = parent_align;
......@@ -28032,6 +28038,7 @@ fn structFieldPtrByIndex(
2803228038 },
2803328039 }
2803428040 } else if (struct_type.layout == .@"extern") {
28041 assert(!field_is_comptime);
2803528042 // For extern structs, field alignment might be bigger than type's
2803628043 // natural alignment. Eg, in `extern struct { x: u32, y: u16 }` the
2803728044 // second field is aligned as u32.
......@@ -28055,7 +28062,7 @@ fn structFieldPtrByIndex(
2805528062
2805628063 const ptr_field_ty = try pt.ptrTypeSema(ptr_ty_data);
2805728064
28058 if (struct_type.fieldIsComptime(ip, field_index)) {
28065 if (field_is_comptime) {
2805928066 try struct_ty.resolveStructFieldInits(pt);
2806028067 const val = try pt.intern(.{ .ptr = .{
2806128068 .ty = ptr_field_ty.toIntern(),
......@@ -28602,7 +28609,8 @@ fn tupleFieldPtr(
2860228609 const pt = sema.pt;
2860328610 const zcu = pt.zcu;
2860428611 const tuple_ptr_ty = sema.typeOf(tuple_ptr);
28605 const tuple_ty = tuple_ptr_ty.childType(zcu);
28612 const tuple_ptr_info = tuple_ptr_ty.ptrInfo(zcu);
28613 const tuple_ty: Type = .fromInterned(tuple_ptr_info.child);
2860628614 try tuple_ty.resolveFields(pt);
2860728615 const field_count = tuple_ty.structFieldCount(zcu);
2860828616
......@@ -28620,9 +28628,16 @@ fn tupleFieldPtr(
2862028628 const ptr_field_ty = try pt.ptrTypeSema(.{
2862128629 .child = field_ty.toIntern(),
2862228630 .flags = .{
28623 .is_const = !tuple_ptr_ty.ptrIsMutable(zcu),
28624 .is_volatile = tuple_ptr_ty.isVolatilePtr(zcu),
28625 .address_space = tuple_ptr_ty.ptrAddressSpace(zcu),
28631 .is_const = tuple_ptr_info.flags.is_const,
28632 .is_volatile = tuple_ptr_info.flags.is_volatile,
28633 .address_space = tuple_ptr_info.flags.address_space,
28634 .alignment = a: {
28635 if (tuple_ptr_info.flags.alignment == .none) break :a .none;
28636 // The tuple pointer isn't naturally aligned, so the field pointer might be underaligned.
28637 const tuple_align = tuple_ptr_info.flags.alignment;
28638 const field_align = try field_ty.abiAlignmentSema(pt);
28639 break :a tuple_align.min(field_align);
28640 },
2862628641 },
2862728642 });
2862828643
src/codegen/c.zig+18-24
......@@ -611,7 +611,7 @@ pub const Function = struct {
611611 const a = try Assignment.start(f, writer, ctype);
612612 try f.writeCValue(writer, dst, .Other);
613613 try a.assign(f, writer);
614 try f.writeCValue(writer, src, .Initializer);
614 try f.writeCValue(writer, src, .Other);
615615 try a.end(f, writer);
616616 }
617617
......@@ -2826,7 +2826,7 @@ pub fn genLazyFn(o: *Object, lazy_ctype_pool: *const CType.Pool, lazy_fn: LazyFn
28262826 });
28272827 try o.dg.renderTypeAndName(w, name_ty, .{ .identifier = "name" }, Const, .none, .complete);
28282828 try w.writeAll(" = ");
2829 try o.dg.renderValue(w, Value.fromInterned(name_val), .Initializer);
2829 try o.dg.renderValue(w, Value.fromInterned(name_val), .StaticInitializer);
28302830 try w.writeAll(";\n return (");
28312831 try o.dg.renderType(w, name_slice_ty);
28322832 try w.print("){{{}, {}}};\n", .{
......@@ -4045,7 +4045,7 @@ fn airStore(f: *Function, inst: Air.Inst.Index, safety: bool) !CValue {
40454045 const new_local = try f.allocLocal(inst, src_ty);
40464046 try f.writeCValue(writer, new_local, .Other);
40474047 try writer.writeAll(" = ");
4048 try f.writeCValue(writer, src_val, .Initializer);
4048 try f.writeCValue(writer, src_val, .Other);
40494049 try writer.writeAll(";\n");
40504050
40514051 break :blk new_local;
......@@ -4516,7 +4516,7 @@ fn airSlice(f: *Function, inst: Air.Inst.Index) !CValue {
45164516 const a = try Assignment.start(f, writer, .usize);
45174517 try f.writeCValueMember(writer, local, .{ .identifier = "len" });
45184518 try a.assign(f, writer);
4519 try f.writeCValue(writer, len, .Initializer);
4519 try f.writeCValue(writer, len, .Other);
45204520 try a.end(f, writer);
45214521 }
45224522 return local;
......@@ -4934,7 +4934,7 @@ fn airSwitchDispatch(f: *Function, inst: Air.Inst.Index) !void {
49344934 const cond_local = f.loop_switch_conds.get(br.block_inst).?;
49354935 try f.writeCValue(writer, .{ .local = cond_local }, .Other);
49364936 try writer.writeAll(" = ");
4937 try f.writeCValue(writer, cond, .Initializer);
4937 try f.writeCValue(writer, cond, .Other);
49384938 try writer.writeAll(";\n");
49394939 try writer.print("goto zig_switch_{d}_loop;", .{@intFromEnum(br.block_inst)});
49404940}
......@@ -4979,14 +4979,8 @@ fn bitcast(f: *Function, dest_ty: Type, operand: CValue, operand_ty: Type) !CVal
49794979 const operand_lval = if (operand == .constant) blk: {
49804980 const operand_local = try f.allocLocal(null, operand_ty);
49814981 try f.writeCValue(writer, operand_local, .Other);
4982 if (operand_ty.isAbiInt(zcu)) {
4983 try writer.writeAll(" = ");
4984 } else {
4985 try writer.writeAll(" = (");
4986 try f.renderType(writer, operand_ty);
4987 try writer.writeByte(')');
4988 }
4989 try f.writeCValue(writer, operand, .Initializer);
4982 try writer.writeAll(" = ");
4983 try f.writeCValue(writer, operand, .Other);
49904984 try writer.writeAll(";\n");
49914985 break :blk operand_local;
49924986 } else operand;
......@@ -5698,7 +5692,7 @@ fn airOptionalPayloadPtrSet(f: *Function, inst: Air.Inst.Index) !CValue {
56985692 const a = try Assignment.start(f, writer, opt_ctype);
56995693 try f.writeCValueDeref(writer, operand);
57005694 try a.assign(f, writer);
5701 try f.object.dg.renderValue(writer, Value.false, .Initializer);
5695 try f.object.dg.renderValue(writer, Value.false, .Other);
57025696 try a.end(f, writer);
57035697 return .none;
57045698 },
......@@ -5718,7 +5712,7 @@ fn airOptionalPayloadPtrSet(f: *Function, inst: Air.Inst.Index) !CValue {
57185712 const a = try Assignment.start(f, writer, opt_ctype);
57195713 try f.writeCValueDerefMember(writer, operand, .{ .identifier = "is_null" });
57205714 try a.assign(f, writer);
5721 try f.object.dg.renderValue(writer, Value.false, .Initializer);
5715 try f.object.dg.renderValue(writer, Value.false, .Other);
57225716 try a.end(f, writer);
57235717 }
57245718 if (f.liveness.isUnused(inst)) return .none;
......@@ -5844,7 +5838,7 @@ fn airFieldParentPtr(f: *Function, inst: Air.Inst.Index) !CValue {
58445838 try writer.writeByte(')');
58455839
58465840 switch (fieldLocation(container_ptr_ty, field_ptr_ty, extra.field_index, pt)) {
5847 .begin => try f.writeCValue(writer, field_ptr_val, .Initializer),
5841 .begin => try f.writeCValue(writer, field_ptr_val, .Other),
58485842 .field => |field| {
58495843 const u8_ptr_ty = try pt.adjustPtrTypeChild(field_ptr_ty, .u8);
58505844
......@@ -5898,7 +5892,7 @@ fn fieldPtr(
58985892 try writer.writeByte(')');
58995893
59005894 switch (fieldLocation(container_ptr_ty, field_ptr_ty, field_index, pt)) {
5901 .begin => try f.writeCValue(writer, container_ptr_val, .Initializer),
5895 .begin => try f.writeCValue(writer, container_ptr_val, .Other),
59025896 .field => |field| {
59035897 try writer.writeByte('&');
59045898 try f.writeCValueDerefMember(writer, container_ptr_val, field);
......@@ -6021,7 +6015,7 @@ fn airStructFieldVal(f: *Function, inst: Air.Inst.Index) !CValue {
60216015 const operand_local = try f.allocLocal(inst, struct_ty);
60226016 try f.writeCValue(writer, operand_local, .Other);
60236017 try writer.writeAll(" = ");
6024 try f.writeCValue(writer, struct_byval, .Initializer);
6018 try f.writeCValue(writer, struct_byval, .Other);
60256019 try writer.writeAll(";\n");
60266020 break :blk operand_local;
60276021 } else struct_byval;
......@@ -6119,7 +6113,7 @@ fn airUnwrapErrUnionPay(f: *Function, inst: Air.Inst.Index, is_ptr: bool) !CValu
61196113 try writer.writeAll(" = (");
61206114 try f.renderType(writer, inst_ty);
61216115 try writer.writeByte(')');
6122 try f.writeCValue(writer, operand, .Initializer);
6116 try f.writeCValue(writer, operand, .Other);
61236117 try writer.writeAll(";\n");
61246118 return local;
61256119 }
......@@ -6164,7 +6158,7 @@ fn airWrapOptional(f: *Function, inst: Air.Inst.Index) !CValue {
61646158 const a = try Assignment.start(f, writer, operand_ctype);
61656159 try f.writeCValueMember(writer, local, .{ .identifier = "payload" });
61666160 try a.assign(f, writer);
6167 try f.writeCValue(writer, operand, .Initializer);
6161 try f.writeCValue(writer, operand, .Other);
61686162 try a.end(f, writer);
61696163 }
61706164 return local;
......@@ -6365,7 +6359,7 @@ fn airArrayToSlice(f: *Function, inst: Air.Inst.Index) !CValue {
63656359 try f.writeCValueMember(writer, local, .{ .identifier = "ptr" });
63666360 try a.assign(f, writer);
63676361 if (operand == .undef) {
6368 try f.writeCValue(writer, .{ .undef = inst_ty.slicePtrFieldType(zcu) }, .Initializer);
6362 try f.writeCValue(writer, .{ .undef = inst_ty.slicePtrFieldType(zcu) }, .Other);
63696363 } else {
63706364 const ptr_ctype = try f.ctypeFromType(ptr_ty, .complete);
63716365 const ptr_child_ctype = ptr_ctype.info(ctype_pool).pointer.elem_ctype;
......@@ -6382,7 +6376,7 @@ fn airArrayToSlice(f: *Function, inst: Air.Inst.Index) !CValue {
63826376 try writer.writeByte('&');
63836377 try f.writeCValueDeref(writer, operand);
63846378 try writer.print("[{}]", .{try f.fmtIntLiteral(try pt.intValue(.usize, 0))});
6385 } else try f.writeCValue(writer, operand, .Initializer);
6379 } else try f.writeCValue(writer, operand, .Other);
63866380 }
63876381 try a.end(f, writer);
63886382 }
......@@ -6912,7 +6906,7 @@ fn airMemset(f: *Function, inst: Air.Inst.Index, safety: bool) !CValue {
69126906 try writer.writeAll("for (");
69136907 try f.writeCValue(writer, index, .Other);
69146908 try writer.writeAll(" = ");
6915 try f.object.dg.renderValue(writer, try pt.intValue(.usize, 0), .Initializer);
6909 try f.object.dg.renderValue(writer, try pt.intValue(.usize, 0), .Other);
69166910 try writer.writeAll("; ");
69176911 try f.writeCValue(writer, index, .Other);
69186912 try writer.writeAll(" != ");
......@@ -7282,7 +7276,7 @@ fn airReduce(f: *Function, inst: Air.Inst.Index) !CValue {
72827276 .float => try pt.floatValue(scalar_ty, std.math.nan(f128)),
72837277 else => unreachable,
72847278 },
7285 }, .Initializer);
7279 }, .Other);
72867280 try writer.writeAll(";\n");
72877281
72887282 const v = try Vectorize.start(f, inst, writer, operand_ty);
test/behavior/tuple.zig+18
......@@ -602,3 +602,21 @@ test "empty union in tuple" {
602602 try std.testing.expectEqualStrings("0", info.@"struct".fields[0].name);
603603 try std.testing.expect(@typeInfo(info.@"struct".fields[0].type) == .@"union");
604604}
605
606test "field pointer of underaligned tuple" {
607 if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
608 const S = struct {
609 fn doTheTest() !void {
610 const T = struct { u8, u32 };
611 var val: T align(2) = .{ 1, 2 };
612
613 comptime assert(@TypeOf(&val[0]) == *u8); // `u8` field pointer isn't overaligned
614 comptime assert(@TypeOf(&val[1]) == *align(2) u32); // `u32` field pointer is correctly underaligned
615
616 try expect(val[0] == 1);
617 try expect(val[1] == 2);
618 }
619 };
620 try S.doTheTest();
621 try comptime S.doTheTest();
622}
test/cases/compile_errors/runtime_store_to_comptime_field.zig created+19
......@@ -0,0 +1,19 @@
1const init: u32 = 1;
2fn rt() u32 {
3 return 3;
4}
5
6var tuple_val = .{init};
7export fn tuple_field() void {
8 tuple_val[0] = rt();
9}
10
11var struct_val = .{ .x = init };
12export fn struct_field() void {
13 struct_val.x = rt();
14}
15
16// error
17//
18// :8:14: error: cannot store runtime value in compile time variable
19// :13:15: error: cannot store runtime value in compile time variable