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C backend: implement Enum types and values

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They are lowered directly as the integer tag type, with no typedef.
This commit is contained in:
Andrew Kelley 2021-04-06 23:19:46 -07:00
parent acf9151008
commit 19cf987198
3 changed files with 53 additions and 9 deletions
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19
src/Sema.zig
View File

@ -1918,11 +1918,20 @@ fn zirEnumToInt(sema: *Sema, block: *Scope.Block, inst: zir.Inst.Index) InnerErr
switch (enum_tag.ty.tag()) {
.enum_full => {
const enum_full = enum_tag.ty.castTag(.enum_full).?.data;
const val = enum_full.values.entries.items[field_index].key;
return mod.constInst(arena, src, .{
.ty = int_tag_ty,
.val = val,
});
if (enum_full.values.count() != 0) {
const val = enum_full.values.entries.items[field_index].key;
return mod.constInst(arena, src, .{
.ty = int_tag_ty,
.val = val,
});
} else {
// Field index and integer values are the same.
const val = try Value.Tag.int_u64.create(arena, field_index);
return mod.constInst(arena, src, .{
.ty = int_tag_ty,
.val = val,
});
}
},
.enum_simple => {
// Field index and integer values are the same.

37
src/codegen/c.zig
View File

@ -172,7 +172,10 @@ pub const DeclGen = struct {
val: Value,
) error{ OutOfMemory, AnalysisFail }!void {
if (val.isUndef()) {
return dg.fail(.{ .node_offset = 0 }, "TODO: C backend: properly handle undefined in all cases (with debug safety?)", .{});
// This should lower to 0xaa bytes in safe modes, and for unsafe modes should
// lower to leaving variables uninitialized (that might need to be implemented
// outside of this function).
return dg.fail(.{ .node_offset = 0 }, "TODO: C backend: implement renderValue undef", .{});
}
switch (t.zigTypeTag()) {
.Int => {
@ -288,6 +291,31 @@ pub const DeclGen = struct {
try writer.writeAll(", .error = 0 }");
}
},
.Enum => {
switch (val.tag()) {
.enum_field_index => {
const field_index = val.castTag(.enum_field_index).?.data;
switch (t.tag()) {
.enum_simple => return writer.print("{d}", .{field_index}),
.enum_full, .enum_nonexhaustive => {
const enum_full = t.cast(Type.Payload.EnumFull).?.data;
if (enum_full.values.count() != 0) {
const tag_val = enum_full.values.entries.items[field_index].key;
return dg.renderValue(writer, enum_full.tag_ty, tag_val);
} else {
return writer.print("{d}", .{field_index});
}
},
else => unreachable,
}
},
else => {
var int_tag_ty_buffer: Type.Payload.Bits = undefined;
const int_tag_ty = t.intTagType(&int_tag_ty_buffer);
return dg.renderValue(writer, int_tag_ty, val);
},
}
},
else => |e| return dg.fail(.{ .node_offset = 0 }, "TODO: C backend: implement value {s}", .{
@tagName(e),
}),
@ -472,6 +500,13 @@ pub const DeclGen = struct {
try w.writeAll(name);
dg.typedefs.putAssumeCapacityNoClobber(t, .{ .name = name, .rendered = rendered });
},
.Enum => {
// For enums, we simply use the integer tag type.
var int_tag_ty_buffer: Type.Payload.Bits = undefined;
const int_tag_ty = t.intTagType(&int_tag_ty_buffer);
try dg.renderType(w, int_tag_ty);
},
.Null, .Undefined => unreachable, // must be const or comptime
else => |e| return dg.fail(.{ .node_offset = 0 }, "TODO: C backend: implement type {s}", .{
@tagName(e),

6
src/type.zig
View File

@ -691,7 +691,7 @@ pub const Type = extern union {
return struct_obj.owner_decl.renderFullyQualifiedName(writer);
},
.enum_full, .enum_nonexhaustive => {
const enum_full = ty.castTag(.enum_full).?.data;
const enum_full = ty.cast(Payload.EnumFull).?.data;
return enum_full.owner_decl.renderFullyQualifiedName(writer);
},
.enum_simple => {
@ -1344,7 +1344,7 @@ pub const Type = extern union {
/// Asserts the type is an enum.
pub fn intTagType(self: Type, buffer: *Payload.Bits) Type {
switch (self.tag()) {
.enum_full, .enum_nonexhaustive => return self.castTag(.enum_full).?.data.tag_ty,
.enum_full, .enum_nonexhaustive => return self.cast(Payload.EnumFull).?.data.tag_ty,
.enum_simple => {
const enum_simple = self.castTag(.enum_simple).?.data;
const bits = std.math.log2_int_ceil(usize, enum_simple.fields.count());
@ -1969,7 +1969,7 @@ pub const Type = extern union {
return null;
}
},
.enum_nonexhaustive => ty = ty.castTag(.enum_full).?.data.tag_ty,
.enum_nonexhaustive => ty = ty.castTag(.enum_nonexhaustive).?.data.tag_ty,
.empty_struct, .empty_struct_literal => return Value.initTag(.empty_struct_value),
.void => return Value.initTag(.void_value),