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

spirv: lower union initialization at runtime

Browse Source
This commit is contained in:
Robin Voetter 2023-09-16 02:53:14 +02:00 committed by Andrew Kelley
parent d06862b759
commit 240f9d740d
1 changed files with 71 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
src/codegen/spirv.zig
View File

@ -1301,6 +1301,72 @@ pub const DeclGen = struct {
.vector_type, .anon_struct_type => unreachable, // TODO
else => unreachable,
},
.un => |un| {
// To initialize a union, generate a temporary variable with the
// type that has the right field active, then pointer-cast and store
// the active field, and finally load and return the entire union.
const layout = ty.unionGetLayout(mod);
const union_ty = mod.typeToUnion(ty).?;
if (union_ty.getLayout(ip) == .Packed) {
return self.todo("packed union types", .{});
} else if (layout.payload_size == 0) {
// No payload, so represent this as just the tag type.
return try self.constant(ty.unionTagTypeSafety(mod).?, un.tag.toValue(), .indirect);
}
const has_tag = layout.tag_size != 0;
const tag_first = layout.tag_align >= layout.payload_align;
const un_ptr_ty_ref = try self.spv.ptrType(result_ty_ref, .Function);
const var_id = self.spv.allocId();
try self.func.prologue.emit(self.spv.gpa, .OpVariable, .{
.id_result_type = self.typeId(un_ptr_ty_ref),
.id_result = var_id,
.storage_class = .Function,
});
const index_ty_ref = try self.intType(.unsigned, 32);
if (has_tag) {
const tag_index: u32 = if (tag_first) 0 else 1;
const index_id = try self.spv.constInt(index_ty_ref, tag_index);
const tag_ty = ty.unionTagTypeSafety(mod).?;
const tag_ty_ref = try self.resolveType(tag_ty, .indirect);
const tag_ptr_ty_ref = try self.spv.ptrType(tag_ty_ref, .Function);
const ptr_id = try self.accessChain(tag_ptr_ty_ref, var_id, &.{index_id});
const tag_id = try self.constant(tag_ty, un.tag.toValue(), .indirect);
try self.func.body.emit(self.spv.gpa, .OpStore, .{
.pointer = ptr_id,
.object = tag_id,
});
}
const pl_index: u32 = if (tag_first) 1 else 0;
const index_id = try self.spv.constInt(index_ty_ref, pl_index);
const active_field = ty.unionTagFieldIndex(un.tag.toValue(), mod).?;
const active_field_ty = union_ty.field_types.get(ip)[active_field].toType();
const active_field_ty_ref = try self.resolveType(active_field_ty, .indirect);
const active_field_ptr_ty_ref = try self.spv.ptrType(active_field_ty_ref, .Function);
const ptr_id = try self.accessChain(active_field_ptr_ty_ref, var_id, &.{index_id});
const value_id = try self.constant(active_field_ty, un.val.toValue(), .indirect);
try self.func.body.emit(self.spv.gpa, .OpStore, .{
.pointer = ptr_id,
.object = value_id,
});
// Just leave the padding fields uninitialized...
const result_id = self.spv.allocId();
try self.func.body.emit(self.spv.gpa, .OpLoad, .{
.id_result_type = self.typeId(result_ty_ref),
.id_result = result_id,
.pointer = var_id,
});
return result_id;
},
else => {
// The value cannot be generated directly, so generate it as an indirect constant,
// and then perform an OpLoad.
@ -1417,7 +1483,7 @@ pub const DeclGen = struct {
if (has_tag and tag_first) {
const tag_ty_ref = try self.resolveType(union_obj.enum_tag_ty.toType(), .indirect);
member_types.appendAssumeCapacity(tag_ty_ref);
member_names.appendAssumeCapacity(try self.spv.resolveString("tag"));
member_names.appendAssumeCapacity(try self.spv.resolveString("(tag)"));
}
const active_field = maybe_active_field orelse layout.most_aligned_field;
@ -1426,7 +1492,7 @@ pub const DeclGen = struct {
const active_field_size = if (active_field_ty.hasRuntimeBitsIgnoreComptime(mod)) blk: {
const active_payload_ty_ref = try self.resolveType(active_field_ty, .indirect);
member_types.appendAssumeCapacity(active_payload_ty_ref);
member_names.appendAssumeCapacity(try self.spv.resolveString("payload"));
member_names.appendAssumeCapacity(try self.spv.resolveString("(payload)"));
break :blk active_field_ty.abiSize(mod);
} else 0;
@ -1434,19 +1500,19 @@ pub const DeclGen = struct {
if (payload_padding_len != 0) {
const payload_padding_ty_ref = try self.spv.arrayType(@as(u32, @intCast(payload_padding_len)), u8_ty_ref);
member_types.appendAssumeCapacity(payload_padding_ty_ref);
member_names.appendAssumeCapacity(try self.spv.resolveString("payload_padding"));
member_names.appendAssumeCapacity(try self.spv.resolveString("(payload padding)"));
}
if (has_tag and !tag_first) {
const tag_ty_ref = try self.resolveType(union_obj.enum_tag_ty.toType(), .indirect);
member_types.appendAssumeCapacity(tag_ty_ref);
member_names.appendAssumeCapacity(try self.spv.resolveString("tag"));
member_names.appendAssumeCapacity(try self.spv.resolveString("(tag)"));
}
if (layout.padding != 0) {
const padding_ty_ref = try self.spv.arrayType(layout.padding, u8_ty_ref);
member_types.appendAssumeCapacity(padding_ty_ref);
member_names.appendAssumeCapacity(try self.spv.resolveString("padding"));
member_names.appendAssumeCapacity(try self.spv.resolveString("(padding)"));
}
const ty_ref = try self.spv.resolve(.{ .struct_type = .{