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cbe: allow immediate and register asm constraints in naked functions

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This commit is contained in:
Jacob Young 2022-10-20 02:04:40 -04:00
parent 4fdac5f1c9
commit 3d90ee50ff
1 changed files with 63 additions and 53 deletions
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116
src/codegen/c.zig
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@ -3526,6 +3526,14 @@ fn airSwitchBr(f: *Function, inst: Air.Inst.Index) !CValue {
return CValue.none;
}
fn asmInputNeedsLocal(constraint: []const u8, value: CValue) bool {
return switch (constraint[0]) {
'{' => true,
'i', 'r' => false,
else => value == .constant,
};
}
fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
const ty_pl = f.air.instructions.items(.data)[inst].ty_pl;
const extra = f.air.extraData(Air.Asm, ty_pl.payload);
@ -3551,10 +3559,9 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
break :local local;
} else .none;
const output_locals_begin = f.next_local_index;
f.next_local_index += outputs.len;
const locals_begin = f.next_local_index;
const constraints_extra_begin = extra_i;
for (outputs) |output, index| {
for (outputs) |output| {
const extra_bytes = std.mem.sliceAsBytes(f.air.extra[extra_i..]);
const constraint = std.mem.sliceTo(extra_bytes, 0);
const name = std.mem.sliceTo(extra_bytes[constraint.len + 1 ..], 0);
@ -3562,12 +3569,17 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
// for the string, we still use the next u32 for the null terminator.
extra_i += (constraint.len + name.len + (2 + 3)) / 4;
const output_ty = if (output == .none) inst_ty else f.air.typeOf(output).childType();
if (std.mem.startsWith(u8, constraint, "={") and std.mem.endsWith(u8, constraint, "}")) {
if (constraint.len < 2 or constraint[0] != '=' or
(constraint[1] == '{' and constraint[constraint.len - 1] != '}'))
{
return f.fail("CBE: constraint not supported: '{s}'", .{constraint});
}
const is_reg = constraint[1] == '{';
if (is_reg) {
const output_ty = if (output == .none) inst_ty else f.air.typeOf(output).childType();
try writer.writeAll("register ");
try f.object.dg.renderTypeAndName(writer, output_ty, .{
.local = output_locals_begin + index,
}, .Mut, 0);
_ = try f.allocLocal(output_ty, .Mut);
try writer.writeAll(" __asm(\"");
try writer.writeAll(constraint["={".len .. constraint.len - "}".len]);
try writer.writeAll("\")");
@ -3576,13 +3588,9 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
try f.writeCValue(writer, .{ .undef = output_ty }, .Initializer);
}
try writer.writeAll(";\n");
} else if (constraint.len < 2 or constraint[0] != '=') {
return f.fail("CBE: constraint not supported: '{s}'", .{constraint});
}
}
const input_locals_begin = f.next_local_index;
f.next_local_index += inputs.len;
for (inputs) |input, index| {
for (inputs) |input| {
const extra_bytes = std.mem.sliceAsBytes(f.air.extra[extra_i..]);
const constraint = std.mem.sliceTo(extra_bytes, 0);
const name = std.mem.sliceTo(extra_bytes[constraint.len + 1 ..], 0);
@ -3590,30 +3598,27 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
// for the string, we still use the next u32 for the null terminator.
extra_i += (constraint.len + name.len + (2 + 3)) / 4;
const input_ty = f.air.typeOf(input);
if (std.mem.startsWith(u8, constraint, "{") and std.mem.endsWith(u8, constraint, "}")) {
try writer.writeAll("register ");
try f.object.dg.renderTypeAndName(writer, input_ty, .{
.local = input_locals_begin + index,
}, .Const, 0);
try writer.writeAll(" __asm(\"");
try writer.writeAll(constraint["{".len .. constraint.len - "}".len]);
try writer.writeAll("\") = ");
try f.writeCValue(writer, try f.resolveInst(input), .Initializer);
try writer.writeAll(";\n");
} else if (constraint.len >= 1 and std.mem.indexOfScalar(u8, "=+&%", constraint[0]) == null) {
const input_val = try f.resolveInst(input);
if (input_val == .constant) {
try f.object.dg.renderTypeAndName(writer, input_ty, .{
.local = input_locals_begin + index,
}, .Const, 0);
try writer.writeAll(" = ");
try f.writeCValue(writer, input_val, .Initializer);
try writer.writeAll(";\n");
}
} else {
if (constraint.len < 1 or std.mem.indexOfScalar(u8, "=+&%", constraint[0]) != null or
(constraint[0] == '{' and constraint[constraint.len - 1] != '}'))
{
return f.fail("CBE: constraint not supported: '{s}'", .{constraint});
}
const is_reg = constraint[0] == '{';
const input_val = try f.resolveInst(input);
if (asmInputNeedsLocal(constraint, input_val)) {
const input_ty = f.air.typeOf(input);
if (is_reg) try writer.writeAll("register ");
_ = try f.allocLocal(input_ty, .Const);
if (is_reg) {
try writer.writeAll(" __asm(\"");
try writer.writeAll(constraint["{".len .. constraint.len - "}".len]);
try writer.writeAll("\")");
}
try writer.writeAll(" = ");
try f.writeCValue(writer, input_val, .Initializer);
try writer.writeAll(";\n");
}
}
{
var clobber_i: u32 = 0;
@ -3631,6 +3636,7 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
try writer.print("({s}", .{fmtStringLiteral(asm_source)});
extra_i = constraints_extra_begin;
var locals_index = locals_begin;
try writer.writeByte(':');
for (outputs) |output, index| {
const extra_bytes = std.mem.sliceAsBytes(f.air.extra[extra_i..]);
@ -3642,11 +3648,13 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
if (index > 0) try writer.writeByte(',');
try writer.writeByte(' ');
if (constraint[1] == '{') {
try writer.print("{s}(", .{fmtStringLiteral("=r")});
try f.writeCValue(writer, .{ .local = output_locals_begin + index }, .Other);
if (!std.mem.eql(u8, name, "_")) try writer.print("[{s}]", .{name});
const is_reg = constraint[1] == '{';
try writer.print("{s}(", .{fmtStringLiteral(if (is_reg) "=r" else constraint)});
if (is_reg) {
try f.writeCValue(writer, .{ .local = locals_index }, .Other);
locals_index += 1;
} else {
try writer.print("{s}(", .{fmtStringLiteral(constraint)});
try f.writeCValueDeref(writer, try f.resolveInst(output));
}
try writer.writeByte(')');
@ -3662,17 +3670,16 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
if (index > 0) try writer.writeByte(',');
try writer.writeByte(' ');
if (constraint[0] == '{') {
try writer.print("{s}(", .{fmtStringLiteral("r")});
try f.writeCValue(writer, .{ .local = input_locals_begin + index }, .Other);
} else {
const input_val = try f.resolveInst(input);
try writer.print("{s}(", .{fmtStringLiteral(constraint)});
try f.writeCValue(writer, if (input_val == .constant)
CValue{ .local = input_locals_begin + index }
else
input_val, .Other);
}
if (!std.mem.eql(u8, name, "_")) try writer.print("[{s}]", .{name});
const is_reg = constraint[0] == '{';
const input_val = try f.resolveInst(input);
try writer.print("{s}(", .{fmtStringLiteral(if (is_reg) "r" else constraint)});
try f.writeCValue(writer, if (asmInputNeedsLocal(constraint, input_val)) local: {
const input_local = CValue{ .local = locals_index };
locals_index += 1;
break :local input_local;
} else input_val, .Other);
try writer.writeByte(')');
}
try writer.writeByte(':');
@ -3693,7 +3700,8 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
try writer.writeAll(");\n");
extra_i = constraints_extra_begin;
for (outputs) |output, index| {
locals_index = locals_begin;
for (outputs) |output| {
const extra_bytes = std.mem.sliceAsBytes(f.air.extra[extra_i..]);
const constraint = std.mem.sliceTo(extra_bytes, 0);
const name = std.mem.sliceTo(extra_bytes[constraint.len + 1 ..], 0);
@ -3701,13 +3709,15 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
// for the string, we still use the next u32 for the null terminator.
extra_i += (constraint.len + name.len + (2 + 3)) / 4;
if (constraint[1] == '{') {
const is_reg = constraint[1] == '{';
if (is_reg) {
try f.writeCValueDeref(writer, if (output == .none)
CValue{ .local_ref = local.local }
else
try f.resolveInst(output));
try writer.writeAll(" = ");
try f.writeCValue(writer, .{ .local = output_locals_begin + index }, .Other);
try f.writeCValue(writer, .{ .local = locals_index }, .Other);
locals_index += 1;
try writer.writeAll(";\n");
}
}