mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-02-13 04:48:20 +00:00
Code Issues Packages Projects Releases Wiki Activity

llvm: do not offset packed struct field pointers if they have a host size

Browse Source 
Closes #14261
This commit is contained in:
Veikka Tuominen 2023-01-13 17:52:54 +02:00
parent 06e9b2c4e3
commit 6e067dc050
2 changed files with 34 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
src/codegen/llvm.zig
View File

@ -3370,7 +3370,7 @@ pub const DeclGen = struct {
return llvm_int.constIntToPtr(try dg.lowerType(tv.ty));
},
.field_ptr, .opt_payload_ptr, .eu_payload_ptr, .elem_ptr => {
return dg.lowerParentPtr(tv.val);
return dg.lowerParentPtr(tv.val, tv.ty.ptrInfo().data.bit_offset % 8 == 0);
},
.null_value, .zero => {
const llvm_type = try dg.lowerType(tv.ty);
@ -3378,7 +3378,7 @@ pub const DeclGen = struct {
},
.opt_payload => {
const payload = tv.val.castTag(.opt_payload).?.data;
return dg.lowerParentPtr(payload);
return dg.lowerParentPtr(payload, tv.ty.ptrInfo().data.bit_offset % 8 == 0);
},
else => |tag| return dg.todo("implement const of pointer type '{}' ({})", .{
tv.ty.fmtDebug(), tag,
@ -3967,7 +3967,7 @@ pub const DeclGen = struct {
return try dg.lowerDeclRefValue(.{ .ty = ptr_ty, .val = ptr_val }, decl_index);
}
fn lowerParentPtr(dg: *DeclGen, ptr_val: Value) Error!*llvm.Value {
fn lowerParentPtr(dg: *DeclGen, ptr_val: Value, byte_aligned: bool) Error!*llvm.Value {
const target = dg.module.getTarget();
switch (ptr_val.tag()) {
.decl_ref_mut => {
@ -3996,7 +3996,7 @@ pub const DeclGen = struct {
},
.field_ptr => {
const field_ptr = ptr_val.castTag(.field_ptr).?.data;
const parent_llvm_ptr = try dg.lowerParentPtr(field_ptr.container_ptr);
const parent_llvm_ptr = try dg.lowerParentPtr(field_ptr.container_ptr, byte_aligned);
const parent_ty = field_ptr.container_ty;
const field_index = @intCast(u32, field_ptr.field_index);
@ -4026,6 +4026,7 @@ pub const DeclGen = struct {
},
.Struct => {
if (parent_ty.containerLayout() == .Packed) {
if (!byte_aligned) return parent_llvm_ptr;
const llvm_usize = dg.context.intType(target.cpu.arch.ptrBitWidth());
const base_addr = parent_llvm_ptr.constPtrToInt(llvm_usize);
// count bits of fields before this one
@ -4072,7 +4073,7 @@ pub const DeclGen = struct {
},
.elem_ptr => {
const elem_ptr = ptr_val.castTag(.elem_ptr).?.data;
const parent_llvm_ptr = try dg.lowerParentPtr(elem_ptr.array_ptr);
const parent_llvm_ptr = try dg.lowerParentPtr(elem_ptr.array_ptr, true);
const llvm_usize = try dg.lowerType(Type.usize);
const indices: [1]*llvm.Value = .{
@ -4083,7 +4084,7 @@ pub const DeclGen = struct {
},
.opt_payload_ptr => {
const opt_payload_ptr = ptr_val.castTag(.opt_payload_ptr).?.data;
const parent_llvm_ptr = try dg.lowerParentPtr(opt_payload_ptr.container_ptr);
const parent_llvm_ptr = try dg.lowerParentPtr(opt_payload_ptr.container_ptr, true);
var buf: Type.Payload.ElemType = undefined;
const payload_ty = opt_payload_ptr.container_ty.optionalChild(&buf);
@ -4105,7 +4106,7 @@ pub const DeclGen = struct {
},
.eu_payload_ptr => {
const eu_payload_ptr = ptr_val.castTag(.eu_payload_ptr).?.data;
const parent_llvm_ptr = try dg.lowerParentPtr(eu_payload_ptr.container_ptr);
const parent_llvm_ptr = try dg.lowerParentPtr(eu_payload_ptr.container_ptr, true);
const payload_ty = eu_payload_ptr.container_ty.errorUnionPayload();
if (!payload_ty.hasRuntimeBitsIgnoreComptime()) {

26
test/behavior/packed-struct.zig
View File

@ -599,3 +599,29 @@ test "packed struct initialized in bitcast" {
const t = @bitCast(u8, T{ .val = val });
try expect(t == val);
}
test "pointer to container level packed struct field" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
const S = packed struct(u32) {
test_bit: bool,
someother_data: u12,
other_test_bit: bool,
someother_more_different_data: u12,
other_bits: packed struct(u6) {
enable_1: bool,
enable_2: bool,
enable_3: bool,
enable_4: bool,
enable_5: bool,
enable_6: bool,
},
var arr = [_]u32{0} ** 2;
};
@ptrCast(*S, &S.arr[0]).other_bits.enable_3 = true;
try expect(S.arr[0] == 0x10000000);
}