60fb50ee5a
Exports now have a dirty flag and are rewritten on flush if this flag has been set. A couple other minor changes have been made based on Andrew's review.
120 lines
4.1 KiB
Zig
120 lines
4.1 KiB
Zig
const std = @import("std");
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const Allocator = std.mem.Allocator;
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const ArrayList = std.ArrayList;
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const assert = std.debug.assert;
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const leb = std.debug.leb;
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const mem = std.mem;
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const Decl = @import("../Module.zig").Decl;
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const Inst = @import("../ir.zig").Inst;
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const Type = @import("../type.zig").Type;
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const Value = @import("../value.zig").Value;
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fn genValtype(ty: Type) u8 {
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return switch (ty.tag()) {
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.u32, .i32 => 0x7F,
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.u64, .i64 => 0x7E,
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.f32 => 0x7D,
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.f64 => 0x7C,
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else => @panic("TODO: Implement more types for wasm."),
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};
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}
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pub fn genFunctype(buf: *ArrayList(u8), decl: *Decl) !void {
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const ty = decl.typed_value.most_recent.typed_value.ty;
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const writer = buf.writer();
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// functype magic
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try writer.writeByte(0x60);
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// param types
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try leb.writeULEB128(writer, @intCast(u32, ty.fnParamLen()));
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if (ty.fnParamLen() != 0) {
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const params = try buf.allocator.alloc(Type, ty.fnParamLen());
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defer buf.allocator.free(params);
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ty.fnParamTypes(params);
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for (params) |param_type| try writer.writeByte(genValtype(param_type));
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}
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// return type
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const return_type = ty.fnReturnType();
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switch (return_type.tag()) {
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.void, .noreturn => try leb.writeULEB128(writer, @as(u32, 0)),
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else => {
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try leb.writeULEB128(writer, @as(u32, 1));
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try writer.writeByte(genValtype(return_type));
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},
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}
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}
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pub fn genCode(buf: *ArrayList(u8), decl: *Decl) !void {
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assert(buf.items.len == 0);
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const writer = buf.writer();
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// Reserve space to write the size after generating the code
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try buf.resize(5);
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// Write the size of the locals vec
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// TODO: implement locals
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try leb.writeULEB128(writer, @as(u32, 0));
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// Write instructions
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// TODO: check for and handle death of instructions
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const tv = decl.typed_value.most_recent.typed_value;
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const mod_fn = tv.val.cast(Value.Payload.Function).?.func;
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for (mod_fn.analysis.success.instructions) |inst| try genInst(writer, inst);
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// Write 'end' opcode
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try writer.writeByte(0x0B);
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// Fill in the size of the generated code to the reserved space at the
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// beginning of the buffer.
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leb.writeUnsignedFixed(5, buf.items[0..5], @intCast(u32, buf.items.len - 5));
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}
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fn genInst(writer: ArrayList(u8).Writer, inst: *Inst) !void {
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return switch (inst.tag) {
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.dbg_stmt => {},
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.ret => genRet(writer, inst.castTag(.ret).?),
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else => error.TODOImplementMoreWasmCodegen,
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};
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}
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fn genRet(writer: ArrayList(u8).Writer, inst: *Inst.UnOp) !void {
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switch (inst.operand.tag) {
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.constant => {
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const constant = inst.operand.castTag(.constant).?;
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switch (inst.operand.ty.tag()) {
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.u32 => {
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try writer.writeByte(0x41); // i32.const
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try leb.writeILEB128(writer, constant.val.toUnsignedInt());
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},
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.i32 => {
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try writer.writeByte(0x41); // i32.const
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try leb.writeILEB128(writer, constant.val.toSignedInt());
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},
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.u64 => {
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try writer.writeByte(0x42); // i64.const
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try leb.writeILEB128(writer, constant.val.toUnsignedInt());
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},
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.i64 => {
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try writer.writeByte(0x42); // i64.const
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try leb.writeILEB128(writer, constant.val.toSignedInt());
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},
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.f32 => {
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try writer.writeByte(0x43); // f32.const
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// TODO: enforce LE byte order
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try writer.writeAll(mem.asBytes(&constant.val.toFloat(f32)));
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},
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.f64 => {
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try writer.writeByte(0x44); // f64.const
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// TODO: enforce LE byte order
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try writer.writeAll(mem.asBytes(&constant.val.toFloat(f64)));
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},
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else => return error.TODOImplementMoreWasmCodegen,
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}
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},
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else => return error.TODOImplementMoreWasmCodegen,
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}
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}
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