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std: cleanup asm usage

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After fixing some issues with inline assembly in the C backend, the std
cleanups have the side effect of making these functions compatible with
the backend, allowing it to be used on linux without linking libc.
This commit is contained in:
Jacob Young
2023-07-30 03:18:10 -04:00
parent 43b8304153
commit 817fa3af86
10 changed files with 278 additions and 222 deletions
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85
src/codegen/c.zig
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@@ -30,7 +30,7 @@ pub const CValue = union(enum) {
/// Address of a local.
local_ref: LocalIndex,
/// A constant instruction, to be rendered inline.
constant: Air.Inst.Ref,
constant: InternPool.Index,
/// Index into the parameters
arg: usize,
/// The array field of a parameter
@@ -302,7 +302,7 @@ pub const Function = struct {
try f.object.dg.renderValue(writer, ty, val, .StaticInitializer);
try writer.writeAll(";\n ");
break :result decl_c_value;
} else .{ .constant = ref };
} else .{ .constant = val.toIntern() };
gop.value_ptr.* = result;
return result;
@@ -352,57 +352,63 @@ pub const Function = struct {
fn writeCValue(f: *Function, w: anytype, c_value: CValue, location: ValueRenderLocation) !void {
switch (c_value) {
.constant => |inst| {
const mod = f.object.dg.module;
const ty = f.typeOf(inst);
const val = (try f.air.value(inst, mod)).?;
return f.object.dg.renderValue(w, ty, val, location);
},
.undef => |ty| return f.object.dg.renderValue(w, ty, Value.undef, location),
else => return f.object.dg.writeCValue(w, c_value),
.constant => |val| try f.object.dg.renderValue(
w,
f.object.dg.module.intern_pool.typeOf(val).toType(),
val.toValue(),
location,
),
.undef => |ty| try f.object.dg.renderValue(w, ty, Value.undef, location),
else => try f.object.dg.writeCValue(w, c_value),
}
}
fn writeCValueDeref(f: *Function, w: anytype, c_value: CValue) !void {
switch (c_value) {
.constant => |inst| {
const mod = f.object.dg.module;
const ty = f.typeOf(inst);
const val = (try f.air.value(inst, mod)).?;
.constant => |val| {
try w.writeAll("(*");
try f.object.dg.renderValue(w, ty, val, .Other);
return w.writeByte(')');
try f.object.dg.renderValue(
w,
f.object.dg.module.intern_pool.typeOf(val).toType(),
val.toValue(),
.Other,
);
try w.writeByte(')');
},
else => return f.object.dg.writeCValueDeref(w, c_value),
else => try f.object.dg.writeCValueDeref(w, c_value),
}
}
fn writeCValueMember(f: *Function, w: anytype, c_value: CValue, member: CValue) !void {
switch (c_value) {
.constant => |inst| {
const mod = f.object.dg.module;
const ty = f.typeOf(inst);
const val = (try f.air.value(inst, mod)).?;
try f.object.dg.renderValue(w, ty, val, .Other);
.constant => |val| {
try f.object.dg.renderValue(
w,
f.object.dg.module.intern_pool.typeOf(val).toType(),
val.toValue(),
.Other,
);
try w.writeByte('.');
return f.writeCValue(w, member, .Other);
try f.writeCValue(w, member, .Other);
},
else => return f.object.dg.writeCValueMember(w, c_value, member),
else => try f.object.dg.writeCValueMember(w, c_value, member),
}
}
fn writeCValueDerefMember(f: *Function, w: anytype, c_value: CValue, member: CValue) !void {
switch (c_value) {
.constant => |inst| {
const mod = f.object.dg.module;
const ty = f.typeOf(inst);
const val = (try f.air.value(inst, mod)).?;
.constant => |val| {
try w.writeByte('(');
try f.object.dg.renderValue(w, ty, val, .Other);
try f.object.dg.renderValue(
w,
f.object.dg.module.intern_pool.typeOf(val).toType(),
val.toValue(),
.Other,
);
try w.writeAll(")->");
return f.writeCValue(w, member, .Other);
try f.writeCValue(w, member, .Other);
},
else => return f.object.dg.writeCValueDerefMember(w, c_value, member),
else => try f.object.dg.writeCValueDerefMember(w, c_value, member),
}
}
@@ -4763,11 +4769,20 @@ fn airSwitchBr(f: *Function, inst: Air.Inst.Index) !CValue {
return .none;
}
fn asmInputNeedsLocal(constraint: []const u8, value: CValue) bool {
fn asmInputNeedsLocal(f: *Function, constraint: []const u8, value: CValue) bool {
return switch (constraint[0]) {
'{' => true,
'i', 'r' => false,
else => value == .constant,
else => switch (value) {
.constant => |val| switch (f.object.dg.module.intern_pool.indexToKey(val)) {
.ptr => |ptr| switch (ptr.addr) {
.decl => false,
else => true,
},
else => true,
},
else => false,
},
};
}
@@ -4848,7 +4863,7 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
const is_reg = constraint[0] == '{';
const input_val = try f.resolveInst(input);
if (asmInputNeedsLocal(constraint, input_val)) {
if (asmInputNeedsLocal(f, constraint, input_val)) {
const input_ty = f.typeOf(input);
if (is_reg) try writer.writeAll("register ");
const alignment = 0;
@@ -4969,7 +4984,7 @@ fn airAsm(f: *Function, inst: Air.Inst.Index) !CValue {
const is_reg = constraint[0] == '{';
const input_val = try f.resolveInst(input);
try writer.print("{s}(", .{fmtStringLiteral(if (is_reg) "r" else constraint, null)});
try f.writeCValue(writer, if (asmInputNeedsLocal(constraint, input_val)) local: {
try f.writeCValue(writer, if (asmInputNeedsLocal(f, constraint, input_val)) local: {
const input_local = .{ .local = locals_index };
locals_index += 1;
break :local input_local;