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Introduce type-erased writers to C backend codegen

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This reduces generic instantiations of several write functions.

Before:

```
@as(type, io.writer.Writer(*array_list.ArrayListAligned(u8,null),error{OutOfMemory},(function 'appendWrite')))
@as(type, io.writer.Writer(*codegen.c.IndentWriter(io.writer.Writer(*array_list.ArrayListAligned(u8,null),error{OutOfMemory},(function 'appendWrite'))),error{OutOfMemory},(function 'write')))
```

After:

```
@as(type, io.GenericWriter(io.Writer,error{OutOfMemory},(function 'write')))
```
This commit is contained in:
Ian Johnson 2023-10-27 22:20:07 -04:00
parent cc25756b3f
commit 2b2c9c5db8
1 changed files with 53 additions and 11 deletions
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64
src/codegen/c.zig
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@ -306,7 +306,7 @@ pub const Function = struct {
const ty = f.typeOf(ref);
const result: CValue = if (lowersToArray(ty, mod)) result: {
const writer = f.object.code_header.writer();
const writer = f.object.codeHeaderWriter();
const alignment: Alignment = .none;
const decl_c_value = try f.allocLocalValue(ty, alignment);
const gpa = f.object.dg.gpa;
@ -534,6 +534,10 @@ pub const Object = struct {
fn writer(o: *Object) IndentWriter(std.ArrayList(u8).Writer).Writer {
return o.indent_writer.writer();
}
fn codeHeaderWriter(o: *Object) ArrayListWriter {
return arrayListWriter(&o.code_header);
}
};
/// This data is available both when outputting .c code and when outputting an .h file.
@ -557,6 +561,10 @@ pub const DeclGen = struct {
flush,
};
fn fwdDeclWriter(dg: *DeclGen) ArrayListWriter {
return arrayListWriter(&dg.fwd_decl);
}
fn fail(dg: *DeclGen, comptime format: []const u8, args: anytype) error{ AnalysisFail, OutOfMemory } {
@setCold(true);
const mod = dg.module;
@ -1997,7 +2005,7 @@ pub const DeclGen = struct {
fwd_kind: enum { tentative, final },
) !void {
const decl = dg.module.declPtr(decl_index);
const fwd = dg.fwd_decl.writer();
const fwd = dg.fwdDeclWriter();
const is_global = variable.is_extern or dg.declIsGlobal(.{ .ty = decl.ty, .val = decl.val });
try fwd.writeAll(if (is_global) "zig_extern " else "static ");
const maybe_exports = dg.module.decl_exports.get(decl_index);
@ -2683,7 +2691,7 @@ fn genExports(o: *Object) !void {
};
const decl = mod.declPtr(decl_index);
const tv: TypedValue = .{ .ty = decl.ty, .val = Value.fromInterned((try decl.internValue(mod))) };
const fwd = o.dg.fwd_decl.writer();
const fwd = o.dg.fwdDeclWriter();
const exports = mod.decl_exports.get(decl_index) orelse return;
if (exports.items.len < 2) return;
@ -2797,7 +2805,7 @@ pub fn genLazyFn(o: *Object, lazy_fn: LazyFnMap.Entry) !void {
const fn_cty = try o.dg.typeToCType(fn_decl.ty, .complete);
const fn_info = fn_cty.cast(CType.Payload.Function).?.data;
const fwd_decl_writer = o.dg.fwd_decl.writer();
const fwd_decl_writer = o.dg.fwdDeclWriter();
try fwd_decl_writer.print("static zig_{s} ", .{@tagName(key)});
try o.dg.renderFunctionSignature(
fwd_decl_writer,
@ -2839,7 +2847,7 @@ pub fn genFunc(f: *Function) !void {
defer o.code_header.deinit();
const is_global = o.dg.declIsGlobal(tv);
const fwd_decl_writer = o.dg.fwd_decl.writer();
const fwd_decl_writer = o.dg.fwdDeclWriter();
try fwd_decl_writer.writeAll(if (is_global) "zig_extern " else "static ");
if (mod.decl_exports.get(decl_index)) |exports|
@ -2894,7 +2902,7 @@ pub fn genFunc(f: *Function) !void {
};
free_locals.sort(SortContext{ .keys = free_locals.keys() });
const w = o.code_header.writer();
const w = o.codeHeaderWriter();
for (free_locals.values()) |list| {
for (list.keys()) |local_index| {
const local = f.locals.items[local_index];
@ -2922,7 +2930,7 @@ pub fn genDecl(o: *Object) !void {
if (!tv.ty.isFnOrHasRuntimeBitsIgnoreComptime(mod)) return;
if (tv.val.getExternFunc(mod)) |_| {
const fwd_decl_writer = o.dg.fwd_decl.writer();
const fwd_decl_writer = o.dg.fwdDeclWriter();
try fwd_decl_writer.writeAll("zig_extern ");
try o.dg.renderFunctionSignature(fwd_decl_writer, decl_index, .forward, .{ .export_index = 0 });
try fwd_decl_writer.writeAll(";\n");
@ -2963,7 +2971,7 @@ pub fn genDeclValue(
link_section: InternPool.OptionalNullTerminatedString,
) !void {
const mod = o.dg.module;
const fwd_decl_writer = o.dg.fwd_decl.writer();
const fwd_decl_writer = o.dg.fwdDeclWriter();
try fwd_decl_writer.writeAll(if (is_global) "zig_extern " else "static ");
try o.dg.renderTypeAndName(fwd_decl_writer, tv.ty, decl_c_value, Const, alignment, .complete);
@ -3007,7 +3015,7 @@ pub fn genHeader(dg: *DeclGen) error{ AnalysisFail, OutOfMemory }!void {
.ty = decl.ty,
.val = decl.val,
};
const writer = dg.fwd_decl.writer();
const writer = dg.fwdDeclWriter();
switch (tv.ty.zigTypeTag(mod)) {
.Fn => if (dg.declIsGlobal(tv)) {
@ -7531,11 +7539,25 @@ fn toAtomicRmwSuffix(order: std.builtin.AtomicRmwOp) []const u8 {
};
}
const ArrayListWriter = ErrorOnlyGenericWriter(std.ArrayList(u8).Writer.Error);
fn arrayListWriter(list: *std.ArrayList(u8)) ArrayListWriter {
return .{ .context = .{
.context = list,
.writeFn = struct {
fn write(context: *const anyopaque, bytes: []const u8) anyerror!usize {
const l: *std.ArrayList(u8) = @alignCast(@constCast(@ptrCast(context)));
return l.writer().write(bytes);
}
}.write,
} };
}
fn IndentWriter(comptime UnderlyingWriter: type) type {
return struct {
const Self = @This();
pub const Error = UnderlyingWriter.Error;
pub const Writer = std.io.Writer(*Self, Error, write);
pub const Writer = ErrorOnlyGenericWriter(Error);
pub const indent_delta = 1;
@ -7544,7 +7566,10 @@ fn IndentWriter(comptime UnderlyingWriter: type) type {
current_line_empty: bool = true,
pub fn writer(self: *Self) Writer {
return .{ .context = self };
return .{ .context = .{
.context = self,
.writeFn = writeAny,
} };
}
pub fn write(self: *Self, bytes: []const u8) Error!usize {
@ -7559,6 +7584,11 @@ fn IndentWriter(comptime UnderlyingWriter: type) type {
return self.writeNoIndent(bytes);
}
fn writeAny(context: *const anyopaque, bytes: []const u8) anyerror!usize {
const self: *Self = @alignCast(@constCast(@ptrCast(context)));
return self.write(bytes);
}
pub fn insertNewline(self: *Self) Error!void {
_ = try self.writeNoIndent("\n");
}
@ -7584,6 +7614,18 @@ fn IndentWriter(comptime UnderlyingWriter: type) type {
};
}
/// A wrapper around `std.io.AnyWriter` that maintains a generic error set while
/// erasing the rest of the implementation. This is intended to avoid duplicate
/// generic instantiations for writer types which share the same error set, while
/// maintaining ease of error handling.
fn ErrorOnlyGenericWriter(comptime Error: type) type {
return std.io.GenericWriter(std.io.AnyWriter, Error, struct {
fn write(context: std.io.AnyWriter, bytes: []const u8) Error!usize {
return @errorCast(context.write(bytes));
}
}.write);
}
fn toCIntBits(zig_bits: u32) ?u32 {
for (&[_]u8{ 8, 16, 32, 64, 128 }) |c_bits| {
if (zig_bits <= c_bits) {