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Merge pull request #10688 from topolarity/c-backend-union-support

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stage2: Add `union` support to C backend
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Andrew Kelley 2022-01-24 23:47:41 -05:00 committed by GitHub
commit 0866fa9d1d
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2 changed files with 197 additions and 58 deletions
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253
src/codegen/c.zig
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@ -34,6 +34,8 @@ pub const CValue = union(enum) {
/// By-value
decl: *Decl,
decl_ref: *Decl,
/// Render the slice as an identifier (using fmtIdent)
identifier: []const u8,
/// Render these bytes literally.
/// TODO make this a [*:0]const u8 to save memory
bytes: []const u8,
@ -78,6 +80,7 @@ fn formatIdent(
) !void {
_ = fmt;
_ = options;
try writer.writeAll("__"); // Add double underscore to avoid conflicting with C's reserved keywords
for (ident) |c, i| {
switch (c) {
'a'...'z', 'A'...'Z', '_' => try writer.writeByte(c),
@ -408,6 +411,18 @@ pub const DeclGen = struct {
try dg.renderValue(writer, Type.usize, slice.len);
try writer.writeAll("}");
},
.elem_ptr => {
const elem_ptr = val.castTag(.elem_ptr).?.data;
var arena = std.heap.ArenaAllocator.init(dg.module.gpa);
defer arena.deinit();
const elem_ptr_ty = try ty.elemPtrType(arena.allocator());
try writer.writeAll("(&((");
try dg.renderType(writer, ty);
try writer.writeByte(')');
try dg.renderValue(writer, elem_ptr_ty, elem_ptr.array_ptr);
try writer.print(")[{d}])", .{elem_ptr.index});
},
.function => {
const func = val.castTag(.function).?.data;
try dg.renderDeclName(func.owner_decl, writer);
@ -527,6 +542,15 @@ pub const DeclGen = struct {
return writer.print("{d}", .{field_index});
}
},
.enum_numbered => {
const enum_obj = ty.castTag(.enum_numbered).?.data;
if (enum_obj.values.count() != 0) {
const tag_val = enum_obj.values.keys()[field_index];
return dg.renderValue(writer, enum_obj.tag_ty, tag_val);
} else {
return writer.print("{d}", .{field_index});
}
},
else => unreachable,
}
},
@ -565,6 +589,37 @@ pub const DeclGen = struct {
try writer.writeAll("}");
},
.Union => {
const union_obj = val.castTag(.@"union").?.data;
const union_ty = ty.cast(Type.Payload.Union).?.data;
const target = dg.module.getTarget();
const layout = ty.unionGetLayout(target);
try writer.writeAll("(");
try dg.renderType(writer, ty);
try writer.writeAll("){");
if (ty.unionTagType()) |tag_ty| {
if (layout.tag_size != 0) {
try writer.writeAll(".tag = ");
try dg.renderValue(writer, tag_ty, union_obj.tag);
try writer.writeAll(", ");
}
try writer.writeAll(".payload = {");
}
const index = union_ty.tag_ty.enumTagFieldIndex(union_obj.tag).?;
const field_ty = ty.unionFields().values()[index].ty;
const field_name = ty.unionFields().keys()[index];
if (field_ty.hasCodeGenBits()) {
try writer.print(".{} = ", .{fmtIdent(field_name)});
try dg.renderValue(writer, field_ty, union_obj.val);
}
if (ty.unionTagType()) |_| {
try writer.writeAll("}");
}
try writer.writeAll("}");
},
.ComptimeInt => unreachable,
.ComptimeFloat => unreachable,
@ -577,7 +632,6 @@ pub const DeclGen = struct {
.BoundFn => unreachable,
.Opaque => unreachable,
.Union,
.Frame,
.AnyFrame,
.Vector,
@ -609,22 +663,24 @@ pub const DeclGen = struct {
try dg.renderDeclName(dg.decl, w);
try w.writeAll("(");
const param_len = dg.decl.ty.fnParamLen();
const is_var_args = dg.decl.ty.fnIsVarArgs();
if (param_len == 0 and !is_var_args)
try w.writeAll("void")
else {
var index: usize = 0;
while (index < param_len) : (index += 1) {
if (index > 0) {
try w.writeAll(", ");
}
try dg.renderType(w, dg.decl.ty.fnParamType(index));
try w.print(" a{d}", .{index});
var index: usize = 0;
var params_written: usize = 0;
while (index < param_len) : (index += 1) {
if (dg.decl.ty.fnParamType(index).zigTypeTag() == .Void) continue;
if (params_written > 0) {
try w.writeAll(", ");
}
try dg.renderType(w, dg.decl.ty.fnParamType(index));
try w.print(" a{d}", .{index});
params_written += 1;
}
if (is_var_args) {
if (param_len != 0) try w.writeAll(", ");
if (dg.decl.ty.fnIsVarArgs()) {
if (params_written != 0) try w.writeAll(", ");
try w.writeAll("...");
} else if (params_written == 0) {
try w.writeAll("void");
}
try w.writeByte(')');
}
@ -646,21 +702,23 @@ pub const DeclGen = struct {
const name_end = buffer.items.len - 2;
const param_len = fn_info.param_types.len;
const is_var_args = fn_info.is_var_args;
if (param_len == 0 and !is_var_args)
try bw.writeAll("void")
else {
var index: usize = 0;
while (index < param_len) : (index += 1) {
if (index > 0) {
try bw.writeAll(", ");
}
try dg.renderType(bw, fn_info.param_types[index]);
var params_written: usize = 0;
var index: usize = 0;
while (index < param_len) : (index += 1) {
if (fn_info.param_types[index].zigTypeTag() == .Void) continue;
if (params_written > 0) {
try bw.writeAll(", ");
}
try dg.renderType(bw, fn_info.param_types[index]);
params_written += 1;
}
if (is_var_args) {
if (param_len != 0) try bw.writeAll(", ");
if (fn_info.is_var_args) {
if (params_written != 0) try bw.writeAll(", ");
try bw.writeAll("...");
} else if (params_written == 0) {
try bw.writeAll("void");
}
try bw.writeAll(");\n");
@ -729,7 +787,7 @@ pub const DeclGen = struct {
if (!field_ty.hasCodeGenBits()) continue;
const alignment = entry.value_ptr.abi_align;
const name: CValue = .{ .bytes = entry.key_ptr.* };
const name: CValue = .{ .identifier = entry.key_ptr.* };
try buffer.append(' ');
try dg.renderTypeAndName(buffer.writer(), field_ty, name, .Mut, alignment);
try buffer.appendSlice(";\n");
@ -753,6 +811,62 @@ pub const DeclGen = struct {
return name;
}
fn renderUnionTypedef(dg: *DeclGen, t: Type) error{ OutOfMemory, AnalysisFail }![]const u8 {
const union_ty = t.cast(Type.Payload.Union).?.data;
const fqn = try union_ty.getFullyQualifiedName(dg.typedefs.allocator);
defer dg.typedefs.allocator.free(fqn);
const target = dg.module.getTarget();
const layout = t.unionGetLayout(target);
var buffer = std.ArrayList(u8).init(dg.typedefs.allocator);
defer buffer.deinit();
try buffer.appendSlice("typedef ");
if (t.unionTagType()) |tag_ty| {
const name: CValue = .{ .bytes = "tag" };
try buffer.appendSlice("struct {\n ");
if (layout.tag_size != 0) {
try dg.renderTypeAndName(buffer.writer(), tag_ty, name, .Mut, Value.initTag(.abi_align_default));
try buffer.appendSlice(";\n");
}
}
try buffer.appendSlice("union {\n");
{
var it = t.unionFields().iterator();
while (it.next()) |entry| {
const field_ty = entry.value_ptr.ty;
if (!field_ty.hasCodeGenBits()) continue;
const alignment = entry.value_ptr.abi_align;
const name: CValue = .{ .identifier = entry.key_ptr.* };
try buffer.append(' ');
try dg.renderTypeAndName(buffer.writer(), field_ty, name, .Mut, alignment);
try buffer.appendSlice(";\n");
}
}
try buffer.appendSlice("} ");
if (t.unionTagType()) |_| {
try buffer.appendSlice("payload;\n} ");
}
const name_start = buffer.items.len;
try buffer.writer().print("zig_U_{s};\n", .{fmtIdent(fqn)});
const rendered = buffer.toOwnedSlice();
errdefer dg.typedefs.allocator.free(rendered);
const name = rendered[name_start .. rendered.len - 2];
try dg.typedefs.ensureUnusedCapacity(1);
dg.typedefs.putAssumeCapacityNoClobber(
try t.copy(dg.typedefs_arena),
.{ .name = name, .rendered = rendered },
);
return name;
}
fn renderErrorUnionTypedef(dg: *DeclGen, t: Type) error{ OutOfMemory, AnalysisFail }![]const u8 {
const child_type = t.errorUnionPayload();
const err_set_type = t.errorUnionSet();
@ -931,6 +1045,12 @@ pub const DeclGen = struct {
return w.writeAll(name);
},
.Union => {
const name = dg.getTypedefName(t) orelse
try dg.renderUnionTypedef(t);
return w.writeAll(name);
},
.Enum => {
// For enums, we simply use the integer tag type.
var int_tag_ty_buffer: Type.Payload.Bits = undefined;
@ -939,7 +1059,6 @@ pub const DeclGen = struct {
try dg.renderType(w, int_tag_ty);
},
.Union,
.Frame,
.AnyFrame,
.Vector,
@ -1021,6 +1140,7 @@ pub const DeclGen = struct {
try w.writeByte('&');
return dg.renderDeclName(decl, w);
},
.identifier => |ident| return w.print("{}", .{fmtIdent(ident)}),
.bytes => |bytes| return w.writeAll(bytes),
}
}
@ -1103,13 +1223,10 @@ pub fn genDecl(o: *Object) !void {
if (variable.is_threadlocal) {
try fwd_decl_writer.writeAll("zig_threadlocal ");
}
try o.dg.renderType(fwd_decl_writer, o.dg.decl.ty);
try fwd_decl_writer.writeAll(" ");
if (is_global) {
try fwd_decl_writer.writeAll(mem.span(o.dg.decl.name));
} else {
try o.dg.renderDeclName(o.dg.decl, fwd_decl_writer);
}
const decl_c_value: CValue = if (is_global) .{ .bytes = mem.span(o.dg.decl.name) } else .{ .decl = o.dg.decl };
try o.dg.renderTypeAndName(fwd_decl_writer, o.dg.decl.ty, decl_c_value, .Mut, o.dg.decl.align_val);
try fwd_decl_writer.writeAll(";\n");
if (variable.init.isUndefDeep()) {
@ -1118,13 +1235,7 @@ pub fn genDecl(o: *Object) !void {
try o.indent_writer.insertNewline();
const w = o.writer();
try o.dg.renderType(w, o.dg.decl.ty);
try w.writeAll(" ");
if (is_global) {
try w.writeAll(mem.span(o.dg.decl.name));
} else {
try o.dg.renderDeclName(o.dg.decl, w);
}
try o.dg.renderTypeAndName(w, o.dg.decl.ty, decl_c_value, .Mut, o.dg.decl.align_val);
try w.writeAll(" = ");
if (variable.init.tag() != .unreachable_value) {
try o.dg.renderValue(w, tv.ty, variable.init);
@ -2339,9 +2450,9 @@ fn airBitcast(f: *Function, inst: Air.Inst.Index) !CValue {
try f.writeCValue(writer, local);
try writer.writeAll(", &");
try f.writeCValue(writer, operand);
try writer.writeAll(", sizeof ");
try writer.writeAll(", sizeof(");
try f.writeCValue(writer, local);
try writer.writeAll(");\n");
try writer.writeAll("));\n");
return local;
}
@ -2650,21 +2761,36 @@ fn airStructFieldPtrIndex(f: *Function, inst: Air.Inst.Index, index: u8) !CValue
fn structFieldPtr(f: *Function, inst: Air.Inst.Index, struct_ptr_ty: Type, struct_ptr: CValue, index: u32) !CValue {
const writer = f.object.writer();
const struct_obj = struct_ptr_ty.elemType().castTag(.@"struct").?.data;
const field_name = struct_obj.fields.keys()[index];
const field_val = struct_obj.fields.values()[index];
const addrof = if (field_val.ty.zigTypeTag() == .Array) "" else "&";
const struct_ty = struct_ptr_ty.elemType();
var field_name: []const u8 = undefined;
var field_val_ty: Type = undefined;
switch (struct_ty.tag()) {
.@"struct" => {
const fields = struct_ty.structFields();
field_name = fields.keys()[index];
field_val_ty = fields.values()[index].ty;
},
.@"union", .union_tagged => {
const fields = struct_ty.unionFields();
field_name = fields.keys()[index];
field_val_ty = fields.values()[index].ty;
},
else => unreachable,
}
const addrof = if (field_val_ty.zigTypeTag() == .Array) "" else "&";
const payload = if (struct_ty.tag() == .union_tagged) "payload." else "";
const inst_ty = f.air.typeOfIndex(inst);
const local = try f.allocLocal(inst_ty, .Const);
switch (struct_ptr) {
.local_ref => |i| {
try writer.print(" = {s}t{d}.{};\n", .{ addrof, i, fmtIdent(field_name) });
try writer.print(" = {s}t{d}.{s}{};\n", .{ addrof, i, payload, fmtIdent(field_name) });
},
else => {
try writer.print(" = {s}", .{addrof});
try f.writeCValue(writer, struct_ptr);
try writer.print("->{};\n", .{fmtIdent(field_name)});
try writer.print("->{s}{};\n", .{ payload, fmtIdent(field_name) });
},
}
return local;
@ -2679,14 +2805,18 @@ fn airStructFieldVal(f: *Function, inst: Air.Inst.Index) !CValue {
const writer = f.object.writer();
const struct_byval = try f.resolveInst(extra.struct_operand);
const struct_ty = f.air.typeOf(extra.struct_operand);
const struct_obj = struct_ty.castTag(.@"struct").?.data;
const field_name = struct_obj.fields.keys()[extra.field_index];
const field_name = switch (struct_ty.tag()) {
.@"struct" => struct_ty.structFields().keys()[extra.field_index],
.@"union", .union_tagged => struct_ty.unionFields().keys()[extra.field_index],
else => unreachable,
};
const payload = if (struct_ty.tag() == .union_tagged) "payload." else "";
const inst_ty = f.air.typeOfIndex(inst);
const local = try f.allocLocal(inst_ty, .Const);
try writer.writeAll(" = ");
try f.writeCValue(writer, struct_byval);
try writer.print(".{};\n", .{fmtIdent(field_name)});
try writer.print(".{s}{};\n", .{ payload, fmtIdent(field_name) });
return local;
}
@ -3027,9 +3157,13 @@ fn airSetUnionTag(f: *Function, inst: Air.Inst.Index) !CValue {
const new_tag = try f.resolveInst(bin_op.rhs);
const writer = f.object.writer();
try writer.writeAll("*");
const union_ty = f.air.typeOf(bin_op.lhs).childType();
const target = f.object.dg.module.getTarget();
const layout = union_ty.unionGetLayout(target);
if (layout.tag_size == 0) return CValue.none;
try f.writeCValue(writer, union_ptr);
try writer.writeAll(" = ");
try writer.writeAll("->tag = ");
try f.writeCValue(writer, new_tag);
try writer.writeAll(";\n");
@ -3043,12 +3177,17 @@ fn airGetUnionTag(f: *Function, inst: Air.Inst.Index) !CValue {
const inst_ty = f.air.typeOfIndex(inst);
const local = try f.allocLocal(inst_ty, .Const);
const ty_op = f.air.instructions.items(.data)[inst].ty_op;
const un_ty = f.air.typeOf(ty_op.operand);
const writer = f.object.writer();
const operand = try f.resolveInst(ty_op.operand);
try writer.writeAll("get_union_tag(");
const target = f.object.dg.module.getTarget();
const layout = un_ty.unionGetLayout(target);
if (layout.tag_size == 0) return CValue.none;
try writer.writeAll(" = ");
try f.writeCValue(writer, operand);
try writer.writeAll(");\n");
try writer.writeAll(".tag;\n");
return local;
}

2
test/behavior.zig
View File

@ -67,6 +67,7 @@ test {
// Tests that pass for stage1, llvm backend, C backend
_ = @import("behavior/cast_int.zig");
_ = @import("behavior/int128.zig");
_ = @import("behavior/union.zig");
_ = @import("behavior/translate_c_macros.zig");
if (builtin.zig_backend != .stage2_c) {
@ -110,7 +111,6 @@ test {
_ = @import("behavior/slice.zig");
_ = @import("behavior/struct_llvm.zig");
_ = @import("behavior/switch.zig");
_ = @import("behavior/union.zig");
_ = @import("behavior/widening.zig");
if (builtin.zig_backend != .stage1) {