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wasm: Fix pointer to field of packed struct

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When requesting a pointer to a field of a packed struct (of which is
not byte-aligned), we simply provide the address of the packed struct
itself.
This commit is contained in:
Luuk de Gram
2022-11-29 21:34:40 +01:00
parent 6924f21bbd
commit df7ddb475e
1 changed files with 27 additions and 9 deletions
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36
src/arch/wasm/CodeGen.zig
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@@ -2166,9 +2166,8 @@ fn airStore(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
break :shifted try func.binOp(extended_value, shift_val, int_elem_ty, .shl);
} else extended_value;
const result = try func.binOp(anded, shifted_value, int_elem_ty, .@"or");
std.debug.print("Host: {} ty {} ty {}\n", .{ ptr_info.host_size, int_elem_ty.fmtDebug(), ty.fmtDebug() });
// lhs is still on the stack
try func.store(.stack, result, int_elem_ty, 0);
try func.store(.stack, result, int_elem_ty, lhs.offset());
}
func.finishAir(inst, .none, &.{ bin_op.lhs, bin_op.rhs });
@@ -2284,8 +2283,10 @@ fn airLoad(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
const int_elem_ty = Type.initPayload(&int_ty_payload.base);
const shift_val = if (ptr_info.host_size <= 4)
WValue{ .imm32 = ptr_info.bit_offset }
else if (ptr_info.host_size <= 8)
WValue{ .imm64 = ptr_info.bit_offset }
else
WValue{ .imm64 = ptr_info.bit_offset };
return func.fail("TODO: airLoad where ptr to bitfield exceeds 64 bits", .{});
const stack_loaded = try func.load(operand, int_elem_ty, 0);
const shifted = try func.binOp(stack_loaded, shift_val, int_elem_ty, .shr);
@@ -3213,7 +3214,7 @@ fn airStructFieldPtr(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
const struct_ptr = try func.resolveInst(extra.data.struct_operand);
const struct_ty = func.air.typeOf(extra.data.struct_operand).childType();
const result = try func.structFieldPtr(extra.data.struct_operand, struct_ptr, struct_ty, extra.data.field_index);
const result = try func.structFieldPtr(inst, extra.data.struct_operand, struct_ptr, struct_ty, extra.data.field_index);
func.finishAir(inst, result, &.{extra.data.struct_operand});
}
@@ -3223,14 +3224,27 @@ fn airStructFieldPtrIndex(func: *CodeGen, inst: Air.Inst.Index, index: u32) Inne
const struct_ptr = try func.resolveInst(ty_op.operand);
const struct_ty = func.air.typeOf(ty_op.operand).childType();
const result = try func.structFieldPtr(ty_op.operand, struct_ptr, struct_ty, index);
const result = try func.structFieldPtr(inst, ty_op.operand, struct_ptr, struct_ty, index);
func.finishAir(inst, result, &.{ty_op.operand});
}
fn structFieldPtr(func: *CodeGen, ref: Air.Inst.Ref, struct_ptr: WValue, struct_ty: Type, index: u32) InnerError!WValue {
fn structFieldPtr(
func: *CodeGen,
inst: Air.Inst.Index,
ref: Air.Inst.Ref,
struct_ptr: WValue,
struct_ty: Type,
index: u32,
) InnerError!WValue {
const result_ty = func.air.typeOfIndex(inst);
const offset = switch (struct_ty.containerLayout()) {
.Packed => switch (struct_ty.zigTypeTag()) {
.Struct => struct_ty.packedStructFieldByteOffset(index, func.target),
.Struct => offset: {
if (result_ty.ptrInfo().data.host_size != 0) {
break :offset @as(u32, 0);
}
break :offset struct_ty.packedStructFieldByteOffset(index, func.target);
},
.Union => 0,
else => unreachable,
},
@@ -3266,11 +3280,15 @@ fn airStructFieldVal(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
assert(struct_obj.layout == .Packed);
const offset = struct_obj.packedFieldBitOffset(func.target, field_index);
const backing_ty = struct_obj.backing_int_ty;
const wasm_bits = toWasmBits(backing_ty.intInfo(func.target).bits).?;
const wasm_bits = toWasmBits(backing_ty.intInfo(func.target).bits) orelse {
return func.fail("TODO: airStructFieldVal for packed structs larger than 128 bits", .{});
};
const const_wvalue = if (wasm_bits == 32)
WValue{ .imm32 = offset }
else if (wasm_bits == 64)
WValue{ .imm64 = offset }
else
WValue{ .imm64 = offset };
return func.fail("TODO: airStructFieldVal for packed structs larger than 64 bits", .{});
// for first field we don't require any shifting
const shifted_value = if (offset == 0)