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https://github.com/ziglang/zig.git
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stage2: refactor wasm backend - similar to the other backends
This commit is contained in:
Luuk de Gram
parent
b204ea0349
commit
bb74f72e97
@ -7,136 +7,292 @@ const mem = std.mem;
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const Module = @import("../Module.zig");
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const Decl = Module.Decl;
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const Inst = @import("../ir.zig").Inst;
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const ir = @import("../ir.zig");
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const Inst = ir.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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const Compilation = @import("../Compilation.zig");
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fn genValtype(ty: Type) u8 {
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/// Wasm Value, created when generating an instruction
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const WValue = union(enum) {
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none: void,
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/// Index of the local variable
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local: u32,
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/// A constant instruction
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constant: *Inst,
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/// Each newly created wasm block have a label
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/// in the form of an index.
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block_idx: u32,
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};
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pub const ValueTable = std.AutoArrayHashMap(*Inst, WValue);
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/// Using a given Zig type, returns the corresponding wasm value type
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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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.u32, .i32 => 0x7F,
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.u64, .i64 => 0x7E,
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else => null,
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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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/// Code represents the `Code` section of wasm that
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/// belongs to a function
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pub const Code = struct {
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/// Reference to the function declaration the code
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/// section belongs to
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decl: *Decl,
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gpa: *mem.Allocator,
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/// Table to save `WValue`'s generated by an `Inst`
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values: ValueTable,
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/// `bytes` contains the wasm instructions that have been emitted
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/// this is what will be emitted after codegen to write the wasm binary
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bytes: ArrayList(u8),
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/// Contains the generated function type bytecode for the current function
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func_type_data: ArrayList(u8),
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/// The index the next local generated will have
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/// NOTE: arguments share the index with locals therefore the first variable
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/// will have the index that comes after the last argument's index
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local_index: u32 = 0,
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/// The index the next argument generated will have
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arg_index: u32 = 0,
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/// If codegen fails, an error messages will be allocated and saved
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/// in `err_msg`
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err_msg: *Compilation.ErrorMsg,
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// functype magic
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try writer.writeByte(0x60);
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const InnerError = error{
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OutOfMemory,
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CodegenFail,
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};
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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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fn fail(self: *Code, src: usize, comptime fmt: []const u8, args: anytype) InnerError {
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self.err_msg = try Compilation.ErrorMsg.create(self.gpa, src, fmt, args);
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return error.CodegenFail;
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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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/// Returns the `WValue` for the given `inst`
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/// creates a new WValue for constants and returns that instead
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fn resolveInst(self: Code, inst: *Inst) !WValue {
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if (inst.value()) |_| {
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return WValue{ .constant = inst };
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}
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return self.values.get(inst).?; // Instruction does not dominate all uses!
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}
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/// Writes the bytecode depending on the given `WValue` in `val`
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fn emitWValue(self: *Code, val: WValue) !void {
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const writer = self.bytes.writer();
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switch (val) {
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.none => unreachable,
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.block_idx => unreachable,
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// loads the local onto the stack at the given index
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.local => |idx| {
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// local.set
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try writer.writeByte(0x20);
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try leb.writeULEB128(writer, idx);
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},
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// creates a new constant onto the stack
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.constant => |inst| try self.emitConstant(inst.castTag(.constant).?),
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}
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}
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fn genFunctype(self: *Code) !void {
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const ty = self.decl.typed_value.most_recent.typed_value.ty;
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const writer = self.func_type_data.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 self.gpa.alloc(Type, ty.fnParamLen());
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defer self.gpa.free(params);
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ty.fnParamTypes(params);
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for (params) |param_type| {
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const val_type = genValtype(param_type) orelse
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return self.fail(self.decl.src(), "TODO: Wasm generate wasm type value for type '{s}'", .{param_type.tag()});
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try writer.writeByte(val_type);
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}
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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 => |ret_type| {
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try leb.writeULEB128(writer, @as(u32, 1));
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const val_type = genValtype(return_type) orelse
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return self.fail(self.decl.src(), "TODO: Wasm generate wasm return type value for type '{s}'", .{ret_type});
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try writer.writeByte(val_type);
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},
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}
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}
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/// Generates the wasm bytecode for the given `code`
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pub fn gen(self: *Code) !void {
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assert(self.bytes.items.len == 0);
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try self.genFunctype();
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const writer = self.bytes.writer();
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// Reserve space to write the size after generating the code
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try self.bytes.resize(5);
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// Write instructions
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// TODO: check for and handle death of instructions
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const tv = self.decl.typed_value.most_recent.typed_value;
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const mod_fn = tv.val.castTag(.function).?.data;
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var locals = std.ArrayList(u8).init(self.gpa);
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defer locals.deinit();
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for (mod_fn.body.instructions) |inst| {
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if (inst.tag != .alloc) continue;
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const alloc: *Inst.NoOp = inst.castTag(.alloc).?;
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const elem_type = alloc.base.ty.elemType();
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const wasm_type = genValtype(elem_type) orelse
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return self.fail(inst.src, "TODO: Wasm generate wasm type value for type '{s}'", .{elem_type.tag()});
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try locals.append(wasm_type);
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}
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try leb.writeULEB128(writer, @intCast(u32, locals.items.len));
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// emit the actual locals amount
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for (locals.items) |local| {
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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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try leb.writeULEB128(writer, local); // valtype
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}
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for (mod_fn.body.instructions) |inst| {
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const result = try self.genInst(inst);
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if (result != .none) {
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try self.values.putNoClobber(inst, result);
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}
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}
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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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const size = self.bytes.items.len - 5 + self.decl.fn_link.wasm.?.idx_refs.items.len * 5;
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leb.writeUnsignedFixed(5, self.bytes.items[0..5], @intCast(u32, size));
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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.castTag(.function).?.data;
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for (mod_fn.body.instructions) |inst| try genInst(buf, decl, 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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const size = buf.items.len - 5 + decl.fn_link.wasm.?.idx_refs.items.len * 5;
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leb.writeUnsignedFixed(5, buf.items[0..5], @intCast(u32, size));
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}
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fn genInst(buf: *ArrayList(u8), decl: *Decl, inst: *Inst) !void {
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return switch (inst.tag) {
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.call => genCall(buf, decl, inst.castTag(.call).?),
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.constant => genConstant(buf, decl, inst.castTag(.constant).?),
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.dbg_stmt => {},
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.ret => genRet(buf, decl, inst.castTag(.ret).?),
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.retvoid => {},
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else => error.TODOImplementMoreWasmCodegen,
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};
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}
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fn genConstant(buf: *ArrayList(u8), decl: *Decl, inst: *Inst.Constant) !void {
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const writer = buf.writer();
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switch (inst.base.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, inst.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, inst.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, inst.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, inst.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(&inst.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(&inst.val.toFloat(f64)));
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},
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.void => {},
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else => return error.TODOImplementMoreWasmCodegen,
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fn genInst(self: *Code, inst: *Inst) !WValue {
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return switch (inst.tag) {
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.alloc => self.genAlloc(inst.castTag(.alloc).?),
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.arg => self.genArg(inst.castTag(.arg).?),
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.call => self.genCall(inst.castTag(.call).?),
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.constant => unreachable,
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.dbg_stmt => WValue.none,
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.load => self.genLoad(inst.castTag(.load).?),
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.ret => self.genRet(inst.castTag(.ret).?),
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.retvoid => WValue.none,
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.store => self.genStore(inst.castTag(.store).?),
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else => self.fail(inst.src, "TODO: Implement wasm inst: {s}", .{inst.tag}),
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};
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}
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}
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fn genRet(buf: *ArrayList(u8), decl: *Decl, inst: *Inst.UnOp) !void {
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try genInst(buf, decl, inst.operand);
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}
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fn genRet(self: *Code, inst: *Inst.UnOp) !WValue {
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const operand = try self.resolveInst(inst.operand);
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try self.emitWValue(operand);
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return WValue.none;
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}
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fn genCall(buf: *ArrayList(u8), decl: *Decl, inst: *Inst.Call) !void {
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const func_inst = inst.func.castTag(.constant).?;
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const func = func_inst.val.castTag(.function).?.data;
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const target = func.owner_decl;
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const target_ty = target.typed_value.most_recent.typed_value.ty;
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fn genCall(self: *Code, inst: *Inst.Call) !WValue {
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const func_inst = inst.func.castTag(.constant).?;
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const func = func_inst.val.castTag(.function).?.data;
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const target = func.owner_decl;
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const target_ty = target.typed_value.most_recent.typed_value.ty;
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if (inst.args.len != 0) return error.TODOImplementMoreWasmCodegen;
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for (inst.args) |arg| {
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const arg_val = try self.resolveInst(arg);
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try self.emitWValue(arg_val);
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}
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try buf.append(0x10); // call
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try self.bytes.append(0x10); // call
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// The function index immediate argument will be filled in using this data
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// in link.Wasm.flush().
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try decl.fn_link.wasm.?.idx_refs.append(buf.allocator, .{
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.offset = @intCast(u32, buf.items.len),
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.decl = target,
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});
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}
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// The function index immediate argument will be filled in using this data
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// in link.Wasm.flush().
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try self.decl.fn_link.wasm.?.idx_refs.append(self.gpa, .{
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.offset = @intCast(u32, self.bytes.items.len),
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.decl = target,
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});
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return WValue.none;
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}
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fn genAlloc(self: *Code, inst: *Inst.NoOp) !WValue {
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defer self.local_index += 1;
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return WValue{ .local = self.local_index };
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}
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fn genStore(self: *Code, inst: *Inst.BinOp) !WValue {
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const writer = self.bytes.writer();
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const lhs = try self.resolveInst(inst.lhs);
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const rhs = try self.resolveInst(inst.rhs);
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try self.emitWValue(rhs);
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try writer.writeByte(0x21); // local.set
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try leb.writeULEB128(writer, lhs.local);
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return WValue.none;
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}
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fn genLoad(self: *Code, inst: *Inst.UnOp) !WValue {
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const operand = self.resolveInst(inst.operand);
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// ensure index to local
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return WValue{ .local = operand.local };
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}
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fn genArg(self: *Code, inst: *Inst.Arg) !WValue {
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// arguments share the index with locals
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defer self.local_index += 1;
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return WValue{ .local = self.local_index };
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}
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fn emitConstant(self: *Code, inst: *Inst.Constant) !void {
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const writer = self.bytes.writer();
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switch (inst.base.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, inst.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, inst.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, inst.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, inst.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(&inst.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(&inst.val.toFloat(f64)));
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},
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.void => {},
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else => |ty| return self.fail(inst.base.src, "Wasm TODO: emitConstant for type {s}", .{ty}),
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}
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}
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};
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@ -118,10 +118,29 @@ pub fn updateDecl(self: *Wasm, module: *Module, decl: *Module.Decl) !void {
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var managed_functype = fn_data.functype.toManaged(self.base.allocator);
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var managed_code = fn_data.code.toManaged(self.base.allocator);
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try codegen.genFunctype(&managed_functype, decl);
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try codegen.genCode(&managed_code, decl);
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fn_data.functype = managed_functype.toUnmanaged();
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fn_data.code = managed_code.toUnmanaged();
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var code = codegen.Code{
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.gpa = self.base.allocator,
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.values = codegen.ValueTable.init(self.base.allocator),
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.bytes = managed_code,
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.func_type_data = managed_functype,
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.decl = decl,
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.err_msg = undefined,
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};
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defer code.values.deinit();
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// generate the 'code' section for the function declaration
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code.gen() catch |err| switch (err) {
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error.CodegenFail => {
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decl.analysis = .codegen_failure;
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try module.failed_decls.put(module.gpa, decl, code.err_msg);
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return;
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},
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else => |e| return err,
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};
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fn_data.functype = code.func_type_data.toUnmanaged();
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fn_data.code = code.bytes.toUnmanaged();
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}
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|
||||
pub fn updateDeclExports(
|
||||
|
||||
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Block a user