300 lines
11 KiB
Zig
300 lines
11 KiB
Zig
const std = @import("std");
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const link = @import("../link.zig");
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const Module = @import("../Module.zig");
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const Inst = @import("../ir.zig").Inst;
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const Value = @import("../value.zig").Value;
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const Type = @import("../type.zig").Type;
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const C = link.File.C;
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const Decl = Module.Decl;
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const mem = std.mem;
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/// Maps a name from Zig source to C. Currently, this will always give the same
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/// output for any given input, sometimes resulting in broken identifiers.
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fn map(allocator: *std.mem.Allocator, name: []const u8) ![]const u8 {
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return allocator.dupe(u8, name);
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}
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fn renderType(ctx: *Context, writer: std.ArrayList(u8).Writer, T: Type) !void {
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switch (T.zigTypeTag()) {
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.NoReturn => {
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try writer.writeAll("zig_noreturn void");
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},
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.Void => try writer.writeAll("void"),
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.Int => {
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if (T.tag() == .u8) {
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ctx.file.need_stdint = true;
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try writer.writeAll("uint8_t");
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} else if (T.tag() == .usize) {
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ctx.file.need_stddef = true;
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try writer.writeAll("size_t");
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} else {
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return ctx.file.fail(ctx.decl.src(), "TODO implement int types", .{});
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}
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},
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else => |e| return ctx.file.fail(ctx.decl.src(), "TODO implement type {}", .{e}),
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}
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}
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fn renderValue(ctx: *Context, writer: std.ArrayList(u8).Writer, T: Type, val: Value) !void {
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switch (T.zigTypeTag()) {
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.Int => {
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if (T.isSignedInt())
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return writer.print("{}", .{val.toSignedInt()});
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return writer.print("{}", .{val.toUnsignedInt()});
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},
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else => |e| return ctx.file.fail(ctx.decl.src(), "TODO implement value {}", .{e}),
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}
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}
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fn renderFunctionSignature(ctx: *Context, writer: std.ArrayList(u8).Writer, decl: *Decl) !void {
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const tv = decl.typed_value.most_recent.typed_value;
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try renderType(ctx, writer, tv.ty.fnReturnType());
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const name = try map(ctx.file.base.allocator, mem.spanZ(decl.name));
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defer ctx.file.base.allocator.free(name);
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try writer.print(" {}(", .{name});
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var param_len = tv.ty.fnParamLen();
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if (param_len == 0)
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try writer.writeAll("void")
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else {
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var index: usize = 0;
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while (index < param_len) : (index += 1) {
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if (index > 0) {
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try writer.writeAll(", ");
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}
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try renderType(ctx, writer, tv.ty.fnParamType(index));
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try writer.print(" arg{}", .{index});
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}
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}
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try writer.writeByte(')');
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}
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pub fn generate(file: *C, decl: *Decl) !void {
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switch (decl.typed_value.most_recent.typed_value.ty.zigTypeTag()) {
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.Fn => try genFn(file, decl),
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.Array => try genArray(file, decl),
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else => |e| return file.fail(decl.src(), "TODO {}", .{e}),
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}
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}
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fn genArray(file: *C, decl: *Decl) !void {
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const tv = decl.typed_value.most_recent.typed_value;
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// TODO: prevent inline asm constants from being emitted
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const name = try map(file.base.allocator, mem.span(decl.name));
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defer file.base.allocator.free(name);
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if (tv.val.cast(Value.Payload.Bytes)) |payload|
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if (tv.ty.sentinel()) |sentinel|
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if (sentinel.toUnsignedInt() == 0)
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try file.constants.writer().print("const char *const {} = \"{}\";\n", .{ name, payload.data })
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else
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return file.fail(decl.src(), "TODO byte arrays with non-zero sentinels", .{})
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else
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return file.fail(decl.src(), "TODO byte arrays without sentinels", .{})
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else
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return file.fail(decl.src(), "TODO non-byte arrays", .{});
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}
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const Context = struct {
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file: *C,
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decl: *Decl,
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inst_map: std.AutoHashMap(*Inst, []u8),
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argdex: usize = 0,
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unnamed_index: usize = 0,
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fn name(self: *Context) ![]u8 {
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const val = try std.fmt.allocPrint(self.file.base.allocator, "__temp_{}", .{self.unnamed_index});
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self.unnamed_index += 1;
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return val;
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}
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fn deinit(self: *Context) void {
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var it = self.inst_map.iterator();
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while (it.next()) |kv| {
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self.file.base.allocator.free(kv.value);
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}
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self.inst_map.deinit();
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self.* = undefined;
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}
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};
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fn genFn(file: *C, decl: *Decl) !void {
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const writer = file.main.writer();
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const tv = decl.typed_value.most_recent.typed_value;
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var ctx = Context{
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.file = file,
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.decl = decl,
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.inst_map = std.AutoHashMap(*Inst, []u8).init(file.base.allocator),
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};
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defer ctx.deinit();
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try renderFunctionSignature(&ctx, writer, decl);
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try writer.writeAll(" {");
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const func: *Module.Fn = tv.val.cast(Value.Payload.Function).?.func;
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const instructions = func.analysis.success.instructions;
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if (instructions.len > 0) {
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try writer.writeAll("\n");
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for (instructions) |inst| {
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if (switch (inst.tag) {
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.assembly => try genAsm(&ctx, inst.castTag(.assembly).?),
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.call => try genCall(&ctx, inst.castTag(.call).?),
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.ret => try genRet(&ctx, inst.castTag(.ret).?),
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.retvoid => try genRetVoid(&ctx),
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.arg => try genArg(&ctx),
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.dbg_stmt => try genDbgStmt(&ctx, inst.castTag(.dbg_stmt).?),
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.breakpoint => try genBreak(&ctx, inst.castTag(.breakpoint).?),
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.unreach => try genUnreach(&ctx, inst.castTag(.unreach).?),
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.intcast => try genIntCast(&ctx, inst.castTag(.intcast).?),
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else => |e| return file.fail(decl.src(), "TODO implement C codegen for {}", .{e}),
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}) |name| {
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try ctx.inst_map.putNoClobber(inst, name);
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}
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}
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}
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try writer.writeAll("}\n\n");
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}
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fn genArg(ctx: *Context) !?[]u8 {
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const name = try std.fmt.allocPrint(ctx.file.base.allocator, "arg{}", .{ctx.argdex});
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ctx.argdex += 1;
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return name;
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}
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fn genRetVoid(ctx: *Context) !?[]u8 {
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try ctx.file.main.writer().print(" return;\n", .{});
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return null;
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}
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fn genRet(ctx: *Context, inst: *Inst.UnOp) !?[]u8 {
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return ctx.file.fail(ctx.decl.src(), "TODO return", .{});
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}
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fn genIntCast(ctx: *Context, inst: *Inst.UnOp) !?[]u8 {
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if (inst.base.isUnused())
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return null;
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const op = inst.operand;
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const writer = ctx.file.main.writer();
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const name = try ctx.name();
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const from = ctx.inst_map.get(op) orelse
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return ctx.file.fail(ctx.decl.src(), "Internal error in C backend: intCast argument not found in inst_map", .{});
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try writer.writeAll(" const ");
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try renderType(ctx, writer, inst.base.ty);
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try writer.print(" {} = (", .{name});
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try renderType(ctx, writer, inst.base.ty);
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try writer.print("){};\n", .{from});
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return name;
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}
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fn genCall(ctx: *Context, inst: *Inst.Call) !?[]u8 {
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const writer = ctx.file.main.writer();
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const header = ctx.file.header.writer();
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try writer.writeAll(" ");
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if (inst.func.castTag(.constant)) |func_inst| {
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if (func_inst.val.cast(Value.Payload.Function)) |func_val| {
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const target = func_val.func.owner_decl;
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const target_ty = target.typed_value.most_recent.typed_value.ty;
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const ret_ty = target_ty.fnReturnType().tag();
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if (target_ty.fnReturnType().hasCodeGenBits() and inst.base.isUnused()) {
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try writer.print("(void)", .{});
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}
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const tname = mem.spanZ(target.name);
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if (ctx.file.called.get(tname) == null) {
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try ctx.file.called.put(tname, void{});
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try renderFunctionSignature(ctx, header, target);
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try header.writeAll(";\n");
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}
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try writer.print("{}(", .{tname});
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if (inst.args.len != 0) {
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for (inst.args) |arg, i| {
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if (i > 0) {
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try writer.writeAll(", ");
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}
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if (arg.cast(Inst.Constant)) |con| {
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try renderValue(ctx, writer, arg.ty, con.val);
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} else {
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return ctx.file.fail(ctx.decl.src(), "TODO call pass arg {}", .{arg});
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}
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}
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}
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try writer.writeAll(");\n");
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} else {
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return ctx.file.fail(ctx.decl.src(), "TODO non-function call target?", .{});
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}
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} else {
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return ctx.file.fail(ctx.decl.src(), "TODO non-constant call inst?", .{});
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}
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return null;
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}
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fn genDbgStmt(ctx: *Context, inst: *Inst.NoOp) !?[]u8 {
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// TODO emit #line directive here with line number and filename
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return null;
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}
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fn genBreak(ctx: *Context, inst: *Inst.NoOp) !?[]u8 {
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// TODO ??
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return null;
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}
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fn genUnreach(ctx: *Context, inst: *Inst.NoOp) !?[]u8 {
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try ctx.file.main.writer().writeAll(" zig_unreachable();\n");
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return null;
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}
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fn genAsm(ctx: *Context, as: *Inst.Assembly) !?[]u8 {
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const writer = ctx.file.main.writer();
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try writer.writeAll(" ");
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for (as.inputs) |i, index| {
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if (i[0] == '{' and i[i.len - 1] == '}') {
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const reg = i[1 .. i.len - 1];
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const arg = as.args[index];
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try writer.writeAll("register ");
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try renderType(ctx, writer, arg.ty);
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try writer.print(" {}_constant __asm__(\"{}\") = ", .{ reg, reg });
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// TODO merge constant handling into inst_map as well
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if (arg.castTag(.constant)) |c| {
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try renderValue(ctx, writer, arg.ty, c.val);
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try writer.writeAll(";\n ");
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} else {
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const gop = try ctx.inst_map.getOrPut(arg);
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if (!gop.found_existing) {
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return ctx.file.fail(ctx.decl.src(), "Internal error in C backend: asm argument not found in inst_map", .{});
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}
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try writer.print("{};\n ", .{gop.entry.value});
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}
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} else {
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return ctx.file.fail(ctx.decl.src(), "TODO non-explicit inline asm regs", .{});
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}
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}
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try writer.print("__asm {} (\"{}\"", .{ if (as.is_volatile) @as([]const u8, "volatile") else "", as.asm_source });
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if (as.output) |o| {
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return ctx.file.fail(ctx.decl.src(), "TODO inline asm output", .{});
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}
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if (as.inputs.len > 0) {
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if (as.output == null) {
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try writer.writeAll(" :");
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}
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try writer.writeAll(": ");
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for (as.inputs) |i, index| {
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if (i[0] == '{' and i[i.len - 1] == '}') {
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const reg = i[1 .. i.len - 1];
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const arg = as.args[index];
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if (index > 0) {
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try writer.writeAll(", ");
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}
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try writer.print("\"\"({}_constant)", .{reg});
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} else {
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// This is blocked by the earlier test
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unreachable;
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}
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}
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}
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try writer.writeAll(");\n");
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return null;
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}
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