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CBE: simplify always_tail call logic

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It should be Sema's job to check this anyway.
This commit is contained in:
Jacob Young 2023-02-23 20:12:02 -05:00
parent 3a1cb62317
commit c0671a92c7
1 changed files with 7 additions and 24 deletions
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31
src/codegen/c.zig
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@ -54,8 +54,6 @@ pub const CValue = union(enum) {
/// Render these bytes literally.
/// TODO make this a [*:0]const u8 to save memory
bytes: []const u8,
/// A deferred call_always_tail
call_always_tail: void,
};
const BlockData = struct {
@ -1751,7 +1749,6 @@ pub const DeclGen = struct {
fmtIdent(ident),
}),
.bytes => |bytes| return w.writeAll(bytes),
.call_always_tail => return dg.fail("CBE: the result of @call(.always_tail, ...) must be returned directly", .{}),
}
}
@ -1785,7 +1782,6 @@ pub const DeclGen = struct {
try w.writeAll(bytes);
return w.writeByte(')');
},
.call_always_tail => return dg.writeCValue(w, c_value),
}
}
@ -1798,16 +1794,7 @@ pub const DeclGen = struct {
fn writeCValueDerefMember(dg: *DeclGen, writer: anytype, c_value: CValue, member: CValue) !void {
switch (c_value) {
.none, .constant, .field, .undef => unreachable,
.new_local,
.local,
.arg,
.arg_array,
.decl,
.identifier,
.payload_identifier,
.bytes,
.call_always_tail,
=> {
.new_local, .local, .arg, .arg_array, .decl, .identifier, .payload_identifier, .bytes => {
try dg.writeCValue(writer, c_value);
try writer.writeAll("->");
},
@ -2910,7 +2897,7 @@ fn genBodyInner(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail,
=> .none,
.call => try airCall(f, inst, .auto),
.call_always_tail => .call_always_tail,
.call_always_tail => .none,
.call_never_tail => try airCall(f, inst, .never_tail),
.call_never_inline => try airCall(f, inst, .never_inline),
@ -3365,20 +3352,15 @@ fn airRet(f: *Function, inst: Air.Inst.Index, is_ptr: bool) !CValue {
const un_op = f.air.instructions.items(.data)[inst].un_op;
const writer = f.object.writer();
const target = f.object.dg.module.getTarget();
const op_inst = Air.refToIndex(un_op);
const op_ty = f.air.typeOf(un_op);
const ret_ty = if (is_ptr) op_ty.childType() else op_ty;
var lowered_ret_buf: LowerFnRetTyBuffer = undefined;
const lowered_ret_ty = lowerFnRetTy(ret_ty, &lowered_ret_buf, target);
const is_naked = if (f.object.dg.decl) |decl| decl.ty.fnCallingConvention() == .Naked else false;
const peek_operand = f.value_map.get(un_op);
if (if (peek_operand) |operand| operand == .call_always_tail else false) {
if (op_inst != null and f.air.instructions.items(.tag)[op_inst.?] == .call_always_tail) {
try reap(f, inst, &.{un_op});
if (is_naked) {
try f.writeCValue(writer, peek_operand.?, .Other);
unreachable;
}
_ = try airCall(f, Air.refToIndex(un_op).?, .always_tail);
_ = try airCall(f, op_inst.?, .always_tail);
} else if (lowered_ret_ty.hasRuntimeBitsIgnoreComptime()) {
const operand = try f.resolveInst(un_op);
try reap(f, inst, &.{un_op});
@ -3412,7 +3394,8 @@ fn airRet(f: *Function, inst: Air.Inst.Index, is_ptr: bool) !CValue {
} else {
try reap(f, inst, &.{un_op});
// Not even allowed to return void in a naked function.
if (!is_naked) try writer.writeAll("return;\n");
if (if (f.object.dg.decl) |decl| decl.ty.fnCallingConvention() != .Naked else true)
try writer.writeAll("return;\n");
}
return .none;
}