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stage2 cbe: regular optional types

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This commit is contained in:
Veikka Tuominen 2021-01-28 20:46:15 +02:00
parent ca20d0ea26
commit c22f010fdd
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GPG Key ID: 59AEB8936E16A6AC
1 changed files with 31 additions and 12 deletions
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43
src/codegen/c.zig
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@ -207,10 +207,12 @@ pub const DeclGen = struct {
if (t.isPtrLikeOptional()) {
return dg.renderValue(writer, child_type, val);
}
try writer.writeByte('(');
try dg.renderType(writer, t);
if (val.tag() == .null_value) {
try writer.writeAll("{ .is_null = true }");
try writer.writeAll("){ .is_null = true }");
} else {
try writer.writeAll("{ .is_null = false, .payload = ");
try writer.writeAll("){ .is_null = false, .payload = ");
try dg.renderValue(writer, child_type, val);
try writer.writeAll(" }");
}
@ -319,7 +321,11 @@ pub const DeclGen = struct {
if (t.isPtrLikeOptional()) {
return dg.renderType(w, child_type);
}
return dg.fail(dg.decl.src(), "TODO: C backend: more optional types", .{});
// TODO this needs to be typedeffed since different structs are different types.
try w.writeAll("struct { ");
try dg.renderType(w, child_type);
try w.writeAll(" payload; bool is_null; }");
},
.Null, .Undefined => unreachable, // must be const or comptime
else => |e| return dg.fail(dg.decl.src(), "TODO: C backend: implement type {s}", .{
@ -834,6 +840,7 @@ fn genAsm(o: *Object, as: *Inst.Assembly) !CValue {
fn genIsNull(o: *Object, inst: *Inst.UnOp) !CValue {
const writer = o.writer();
const invert_logic = inst.base.tag == .is_non_null or inst.base.tag == .is_non_null_ptr;
const operator = if (invert_logic) "!=" else "==";
const maybe_deref = if (inst.base.tag == .is_null_ptr or inst.base.tag == .is_non_null_ptr) "[0]" else "";
const operand = try o.resolveInst(inst.operand);
@ -843,10 +850,8 @@ fn genIsNull(o: *Object, inst: *Inst.UnOp) !CValue {
if (inst.operand.ty.isPtrLikeOptional()) {
// operand is a regular pointer, test `operand !=/== NULL`
const operator = if (invert_logic) "!=" else "==";
try writer.print("){s} {s} NULL;\n", .{ maybe_deref, operator });
} else {
const operator = if (invert_logic) "!=" else "==";
try writer.print("){s}.is_null {s} true;\n", .{ maybe_deref, operator });
}
return local;
@ -856,17 +861,26 @@ fn genOptionalPayload(o: *Object, inst: *Inst.UnOp) !CValue {
const writer = o.writer();
const operand = try o.resolveInst(inst.operand);
if (opt_ty.isPtrLikeOptional()) {
// the operand is just a regular pointer, no need to do anything special.
return operand;
}
const opt_ty = if (inst.operand.ty.zigTypeTag() == .Pointer)
inst.operand.ty.elemType()
else
inst.operand.ty;
return o.dg.fail(o.dg.decl.src(), "TODO: C backend: genOptionalPayload non ptr-like optionals", .{});
if (opt_ty.isPtrLikeOptional()) {
// the operand is just a regular pointer, no need to do anything special.
// *?*T -> **T and ?*T -> *T are **T -> **T and *T -> *T in C
return operand;
}
const maybe_deref = if (inst.operand.ty.zigTypeTag() == .Pointer) "->" else ".";
const maybe_addrof = if (inst.base.ty.zigTypeTag() == .Pointer) "&" else "";
const local = try o.allocLocal(inst.base.ty, .Const);
try writer.print(" = {s}(", .{maybe_addrof});
try o.writeCValue(writer, operand);
try writer.print("){s}payload;\n", .{maybe_deref});
return local;
}
fn genWrapOptional(o: *Object, inst: *Inst.UnOp) !CValue {
@ -878,7 +892,12 @@ fn genWrapOptional(o: *Object, inst: *Inst.UnOp) !CValue {
return operand;
}
return o.dg.fail(o.dg.decl.src(), "TODO: C backend: genWrapOptional non ptr-like optionals", .{});
// .wrap_optional is used to convert non-optionals into optionals so it can never be null.
const local = try o.allocLocal(inst.base.ty, .Const);
try writer.writeAll(" = { .is_null = false, .payload =");
try o.writeCValue(writer, operand);
try writer.writeAll("};\n");
return local;
}
fn IndentWriter(comptime UnderlyingWriter: type) type {