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LLVM: add padding to optional types when lowering

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If the LLVM ABI size does not agree with the Zig ABI size.
This commit is contained in:
Andrew Kelley 2022-07-14 20:05:55 -07:00
parent 070e3ea37d
commit 9c136be78f
1 changed files with 31 additions and 11 deletions
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42
src/codegen/llvm.zig
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@ -2537,10 +2537,22 @@ pub const DeclGen = struct {
return payload_llvm_ty;
}
comptime assert(optional_layout_version == 1);
const fields: [2]*const llvm.Type = .{
payload_llvm_ty, dg.context.intType(1),
payload_llvm_ty,
dg.context.intType(1),
};
return dg.context.structType(&fields, fields.len, .False);
const llvm_ty = dg.context.structType(&fields, fields.len, .False);
const llvm_size = dg.object.target_data.abiSizeOfType(llvm_ty);
const zig_size = t.abiSize(target);
const padding = @intCast(c_uint, zig_size - llvm_size);
if (padding == 0) return llvm_ty;
const padded_fields: [3]*const llvm.Type = .{
payload_llvm_ty,
dg.context.intType(1),
dg.context.intType(8).arrayType(padding),
};
return dg.context.structType(&padded_fields, padded_fields.len, .False);
},
.ErrorUnion => {
const payload_ty = t.errorUnionPayload();
@ -3101,6 +3113,7 @@ pub const DeclGen = struct {
else => unreachable,
},
.Optional => {
comptime assert(optional_layout_version == 1);
var buf: Type.Payload.ElemType = undefined;
const payload_ty = tv.ty.optionalChild(&buf);
const llvm_i1 = dg.context.intType(1);
@ -3109,25 +3122,30 @@ pub const DeclGen = struct {
if (!payload_ty.hasRuntimeBitsIgnoreComptime()) {
return non_null_bit;
}
const llvm_ty = try dg.lowerType(tv.ty);
if (tv.ty.optionalReprIsPayload()) {
if (tv.val.castTag(.opt_payload)) |payload| {
return dg.lowerValue(.{ .ty = payload_ty, .val = payload.data });
} else if (is_pl) {
return dg.lowerValue(.{ .ty = payload_ty, .val = tv.val });
} else {
const llvm_ty = try dg.lowerType(tv.ty);
return llvm_ty.constNull();
}
}
assert(payload_ty.zigTypeTag() != .Fn);
const fields: [2]*const llvm.Value = .{
try dg.lowerValue(.{
.ty = payload_ty,
.val = if (tv.val.castTag(.opt_payload)) |pl| pl.data else Value.initTag(.undef),
}),
non_null_bit,
};
return dg.context.constStruct(&fields, fields.len, .False);
const llvm_field_count = llvm_ty.countStructElementTypes();
var fields_buf: [3]*const llvm.Value = undefined;
fields_buf[0] = try dg.lowerValue(.{
.ty = payload_ty,
.val = if (tv.val.castTag(.opt_payload)) |pl| pl.data else Value.initTag(.undef),
});
fields_buf[1] = non_null_bit;
if (llvm_field_count > 2) {
assert(llvm_field_count == 3);
fields_buf[2] = llvm_ty.structGetTypeAtIndex(2).getUndef();
}
return dg.context.constStruct(&fields_buf, llvm_field_count, .False);
},
.Fn => {
const fn_decl_index = switch (tv.val.tag()) {
@ -5865,6 +5883,7 @@ pub const FuncGen = struct {
const ty_op = self.air.instructions.items(.data)[inst].ty_op;
const payload_ty = self.air.typeOf(ty_op.operand);
const non_null_bit = self.context.intType(1).constAllOnes();
comptime assert(optional_layout_version == 1);
if (!payload_ty.hasRuntimeBitsIgnoreComptime()) return non_null_bit;
const operand = try self.resolveInst(ty_op.operand);
const optional_ty = self.air.typeOfIndex(inst);
@ -9318,6 +9337,7 @@ fn intrinsicsAllowed(scalar_ty: Type, target: std.Target) bool {
/// We can do this because for all types, Zig ABI alignment >= LLVM ABI
/// alignment.
const struct_layout_version = 2;
const optional_layout_version = 1;
/// We use the least significant bit of the pointer address to tell us
/// whether the type is fully resolved. Types that are only fwd declared