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C backend: fix enough that zig test works

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* test_functions: properly add dependencies of the array on test
   functions and test names so that the order comes out correctly.
 * fix lowering of struct literals to add parentheses around the type
   name.
 * omit const qualifier in slices because otherwise slices cannot be
   reassigned even when they are local variables.
 * special case pointer to functions and double pointer to functions in
   renderTypeAndName. This code will need to be cleaned up but for now
   it helps us make progress on other C backend stuff.
 * fix slice element access to lower to `.ptr[` instead of `[`.
 * airSliceElemVal: respect volatile slices
This commit is contained in:
Andrew Kelley 2021-10-28 15:59:14 -07:00
parent 234d94e42b
commit d2f9646d98
3 changed files with 117 additions and 48 deletions
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6
src/Module.zig
View File

@ -4734,6 +4734,10 @@ pub fn populateTestFunctions(mod: *Module) !void {
}),
.val = try Value.Tag.array.create(arena, test_fn_vals),
});
// Add a dependency on each test name and function pointer.
try array_decl.dependencies.ensureUnusedCapacity(gpa, test_fn_vals.len * 2);
for (mod.test_functions.keys()) |test_decl, i| {
const test_name_slice = mem.sliceTo(test_decl.name, 0);
const test_name_decl = n: {
@ -4747,6 +4751,8 @@ pub fn populateTestFunctions(mod: *Module) !void {
try test_name_decl.finalizeNewArena(&name_decl_arena);
break :n test_name_decl;
};
array_decl.dependencies.putAssumeCapacityNoClobber(test_decl, {});
array_decl.dependencies.putAssumeCapacityNoClobber(test_name_decl, {});
try mod.linkerUpdateDecl(test_name_decl);
const field_vals = try arena.create([3]Value);

151
src/codegen/c.zig
View File

@ -397,8 +397,9 @@ pub const DeclGen = struct {
.Struct => {
const field_vals = val.castTag(.@"struct").?.data;
try writer.writeAll("(");
try dg.renderType(writer, ty);
try writer.writeAll("{");
try writer.writeAll("){");
for (field_vals) |field_val, i| {
const field_ty = ty.structFieldType(i);
@ -529,9 +530,9 @@ pub const DeclGen = struct {
const elem_type = t.elemType();
try dg.renderType(bw, elem_type);
try bw.writeAll(" *");
if (t.isConstPtr()) {
try bw.writeAll("const ");
}
// We skip the const qualifier because C's type system
// would not allow a local mutable variable which is this slice type
// to be overwritten with a new slice type.
if (t.isVolatilePtr()) {
try bw.writeAll("volatile ");
}
@ -549,15 +550,40 @@ pub const DeclGen = struct {
try t.copy(dg.typedefs_arena),
.{ .name = name, .rendered = rendered },
);
} else {
try dg.renderType(w, t.elemType());
try w.writeAll(" *");
if (t.isConstPtr()) {
try w.writeAll("const ");
return;
}
if (t.castPtrToFn()) |fn_ty| {
const fn_info = fn_ty.fnInfo();
try dg.renderType(w, fn_info.return_type);
try w.writeAll(" (*)(");
const param_len = fn_info.param_types.len;
const is_var_args = fn_info.is_var_args;
if (param_len == 0 and !is_var_args)
try w.writeAll("void")
else {
var index: usize = 0;
while (index < param_len) : (index += 1) {
if (index > 0) {
try w.writeAll(", ");
}
try dg.renderType(w, fn_info.param_types[index]);
}
}
if (t.isVolatilePtr()) {
try w.writeAll("volatile ");
if (is_var_args) {
if (param_len != 0) try w.writeAll(", ");
try w.writeAll("...");
}
try w.writeByte(')');
return;
}
try dg.renderType(w, t.elemType());
try w.writeAll(" *");
if (t.isConstPtr()) {
try w.writeAll("const ");
}
if (t.isVolatilePtr()) {
try w.writeAll("volatile ");
}
},
.Array => {
@ -685,28 +711,7 @@ pub const DeclGen = struct {
try dg.renderType(w, int_tag_ty);
},
.Union => return dg.fail("TODO: C backend: implement type Union", .{}),
.Fn => {
try dg.renderType(w, t.fnReturnType());
try w.writeAll(" (*)(");
const param_len = t.fnParamLen();
const is_var_args = t.fnIsVarArgs();
if (param_len == 0 and !is_var_args)
try w.writeAll("void")
else {
var index: usize = 0;
while (index < param_len) : (index += 1) {
if (index > 0) {
try w.writeAll(", ");
}
try dg.renderType(w, t.fnParamType(index));
}
}
if (is_var_args) {
if (param_len != 0) try w.writeAll(", ");
try w.writeAll("...");
}
try w.writeByte(')');
},
.Fn => unreachable, // This is a function body, not a function pointer.
.Opaque => return dg.fail("TODO: C backend: implement type Opaque", .{}),
.Frame => return dg.fail("TODO: C backend: implement type Frame", .{}),
.AnyFrame => return dg.fail("TODO: C backend: implement type AnyFrame", .{}),
@ -742,8 +747,59 @@ pub const DeclGen = struct {
render_ty = render_ty.elemType();
}
if (render_ty.zigTypeTag() == .Fn) {
const ret_ty = render_ty.fnReturnType();
// TODO this is duplicated from the code below and does not handle
// arbitrary nesting of pointers. This renderTypeAndName function
// needs to be reworked by someone who understands C's insane type syntax. That
// person might be future me but it is certainly not present me.
if (render_ty.zigTypeTag() == .Pointer and
render_ty.childType().zigTypeTag() == .Pointer and
render_ty.childType().childType().zigTypeTag() == .Fn)
{
const ptr2_ty = render_ty.childType();
const fn_info = ptr2_ty.childType().fnInfo();
const ret_ty = fn_info.return_type;
if (ret_ty.zigTypeTag() == .NoReturn) {
// noreturn attribute is not allowed here.
try w.writeAll("void");
} else {
try dg.renderType(w, ret_ty);
}
try w.writeAll(" (*");
switch (mutability) {
.Const => try w.writeAll("const "),
.Mut => {},
}
if (!ptr2_ty.ptrIsMutable()) {
try w.writeAll("*const ");
} else {
try w.writeAll("*");
}
try dg.writeCValue(w, name);
try w.writeAll(")(");
const param_len = fn_info.param_types.len;
const is_var_args = fn_info.is_var_args;
if (param_len == 0 and !is_var_args)
try w.writeAll("void")
else {
var index: usize = 0;
while (index < param_len) : (index += 1) {
if (index > 0) {
try w.writeAll(", ");
}
try dg.renderType(w, fn_info.param_types[index]);
}
}
if (is_var_args) {
if (param_len != 0) try w.writeAll(", ");
try w.writeAll("...");
}
try w.writeByte(')');
return;
}
if (render_ty.castPtrToFn()) |fn_ty| {
const fn_info = fn_ty.fnInfo();
const ret_ty = fn_info.return_type;
if (ret_ty.zigTypeTag() == .NoReturn) {
// noreturn attribute is not allowed here.
try w.writeAll("void");
@ -757,8 +813,8 @@ pub const DeclGen = struct {
}
try dg.writeCValue(w, name);
try w.writeAll(")(");
const param_len = render_ty.fnParamLen();
const is_var_args = render_ty.fnIsVarArgs();
const param_len = fn_info.param_types.len;
const is_var_args = fn_info.is_var_args;
if (param_len == 0 and !is_var_args)
try w.writeAll("void")
else {
@ -767,7 +823,7 @@ pub const DeclGen = struct {
if (index > 0) {
try w.writeAll(", ");
}
try dg.renderType(w, render_ty.fnParamType(index));
try dg.renderType(w, fn_info.param_types[index]);
}
}
if (is_var_args) {
@ -1083,7 +1139,7 @@ fn genBody(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail, OutO
.ptr_elem_val => try airPtrElemVal(f, inst, "["),
.ptr_elem_ptr => try airPtrElemPtr(f, inst),
.slice_elem_val => try airSliceElemVal(f, inst, "["),
.slice_elem_val => try airSliceElemVal(f, inst),
.slice_elem_ptr => try airSliceElemPtr(f, inst),
.array_elem_val => try airArrayElemVal(f, inst),
@ -1149,27 +1205,26 @@ fn airPtrElemPtr(f: *Function, inst: Air.Inst.Index) !CValue {
return f.fail("TODO: C backend: airPtrElemPtr", .{});
}
fn airSliceElemVal(f: *Function, inst: Air.Inst.Index, prefix: []const u8) !CValue {
const is_volatile = false; // TODO
if (!is_volatile and f.liveness.isUnused(inst))
return CValue.none;
fn airSliceElemVal(f: *Function, inst: Air.Inst.Index) !CValue {
const bin_op = f.air.instructions.items(.data)[inst].bin_op;
const slice_ty = f.air.typeOf(bin_op.lhs);
if (!slice_ty.isVolatilePtr() and f.liveness.isUnused(inst)) return CValue.none;
const slice = try f.resolveInst(bin_op.lhs);
const index = try f.resolveInst(bin_op.rhs);
const writer = f.object.writer();
const local = try f.allocLocal(f.air.typeOfIndex(inst), .Const);
try writer.writeAll(" = ");
try f.writeCValue(writer, slice);
try writer.writeAll(prefix);
try writer.writeAll(".ptr[");
try f.writeCValue(writer, index);
try writer.writeAll("];\n");
return local;
}
fn airSliceElemPtr(f: *Function, inst: Air.Inst.Index) !CValue {
if (f.liveness.isUnused(inst))
return CValue.none;
if (f.liveness.isUnused(inst)) return CValue.none;
const ty_pl = f.air.instructions.items(.data)[inst].ty_pl;
const bin_op = f.air.extraData(Air.Bin, ty_pl.payload).data;
@ -1179,7 +1234,7 @@ fn airSliceElemPtr(f: *Function, inst: Air.Inst.Index) !CValue {
const local = try f.allocLocal(f.air.typeOfIndex(inst), .Const);
try writer.writeAll(" = &");
try f.writeCValue(writer, slice);
try writer.writeByte('[');
try writer.writeAll(".ptr[");
try f.writeCValue(writer, index);
try writer.writeAll("];\n");
return local;

8
src/type.zig
View File

@ -252,6 +252,14 @@ pub const Type = extern union {
};
}
/// If it is a function pointer, returns the function type. Otherwise returns null.
pub fn castPtrToFn(ty: Type) ?Type {
if (ty.zigTypeTag() != .Pointer) return null;
const elem_ty = ty.childType();
if (elem_ty.zigTypeTag() != .Fn) return null;
return elem_ty;
}
pub fn ptrIsMutable(ty: Type) bool {
return switch (ty.tag()) {
.single_const_pointer_to_comptime_int,