diff options
Diffstat (limited to 'src/codegen')
| -rw-r--r-- | src/codegen/wasm.zig | 335 |
1 files changed, 267 insertions, 68 deletions
diff --git a/src/codegen/wasm.zig b/src/codegen/wasm.zig index cbb2a42189..abc411b551 100644 --- a/src/codegen/wasm.zig +++ b/src/codegen/wasm.zig @@ -4,6 +4,7 @@ const ArrayList = std.ArrayList; const assert = std.debug.assert; const leb = std.leb; const mem = std.mem; +const wasm = std.wasm; const Module = @import("../Module.zig"); const Decl = Module.Decl; @@ -12,6 +13,7 @@ const Inst = ir.Inst; const Type = @import("../type.zig").Type; const Value = @import("../value.zig").Value; const Compilation = @import("../Compilation.zig"); +const AnyMCValue = @import("../codegen.zig").AnyMCValue; /// Wasm Value, created when generating an instruction const WValue = union(enum) { @@ -20,23 +22,14 @@ const WValue = union(enum) { local: u32, /// Instruction holding a constant `Value` constant: *Inst, - /// Block label + /// Offset position in the list of bytecode instructions + code_offset: usize, + /// The label of the block, used by breaks to find its relative distance block_idx: u32, }; /// Hashmap to store generated `WValue` for each `Inst` -pub const ValueTable = std.AutoHashMap(*Inst, WValue); - -/// Using a given `Type`, returns the corresponding wasm value type -fn genValtype(ty: Type) ?u8 { - return switch (ty.tag()) { - .f32 => 0x7D, - .f64 => 0x7C, - .u32, .i32 => 0x7F, - .u64, .i64 => 0x7E, - else => null, - }; -} +pub const ValueTable = std.AutoHashMapUnmanaged(*Inst, WValue); /// Code represents the `Code` section of wasm that /// belongs to a function @@ -58,13 +51,25 @@ pub const Context = struct { local_index: u32 = 0, /// If codegen fails, an error messages will be allocated and saved in `err_msg` err_msg: *Module.ErrorMsg, + /// Current block depth. Used to calculate the relative difference between a break + /// and block + block_depth: u32 = 0, + /// List of all locals' types generated throughout this declaration + /// used to emit locals count at start of 'code' section. + locals: std.ArrayListUnmanaged(u8), const InnerError = error{ OutOfMemory, CodegenFail, }; - /// Sets `err_msg` on `Context` and returns `error.CodegenFail` which is caught in link/Wasm.zig + pub fn deinit(self: *Context) void { + self.values.deinit(self.gpa); + self.locals.deinit(self.gpa); + self.* = undefined; + } + + /// Sets `err_msg` on `Context` and returns `error.CodegemFail` which is caught in link/Wasm.zig fn fail(self: *Context, src: usize, comptime fmt: []const u8, args: anytype) InnerError { self.err_msg = try Module.ErrorMsg.create(self.gpa, .{ .file_scope = self.decl.getFileScope(), @@ -85,13 +90,35 @@ pub const Context = struct { return self.values.get(inst).?; // Instruction does not dominate all uses! } + /// Using a given `Type`, returns the corresponding wasm value type + fn genValtype(self: *Context, src: usize, ty: Type) InnerError!u8 { + return switch (ty.tag()) { + .f32 => wasm.valtype(.f32), + .f64 => wasm.valtype(.f64), + .u32, .i32 => wasm.valtype(.i32), + .u64, .i64 => wasm.valtype(.i64), + else => self.fail(src, "TODO - Wasm genValtype for type '{s}'", .{ty.tag()}), + }; + } + + /// Using a given `Type`, returns the corresponding wasm value type + /// Differently from `genValtype` this also allows `void` to create a block + /// with no return type + fn genBlockType(self: *Context, src: usize, ty: Type) InnerError!u8 { + return switch (ty.tag()) { + .void, .noreturn => wasm.block_empty, + else => self.genValtype(src, ty), + }; + } + /// Writes the bytecode depending on the given `WValue` in `val` fn emitWValue(self: *Context, val: WValue) InnerError!void { const writer = self.code.writer(); switch (val) { - .none, .block_idx => {}, + .block_idx => unreachable, + .none, .code_offset => {}, .local => |idx| { - try writer.writeByte(0x20); // local.get + try writer.writeByte(wasm.opcode(.local_get)); try leb.writeULEB128(writer, idx); }, .constant => |inst| try self.emitConstant(inst.castTag(.constant).?), // creates a new constant onto the stack @@ -102,8 +129,7 @@ pub const Context = struct { const ty = self.decl.typed_value.most_recent.typed_value.ty; const writer = self.func_type_data.writer(); - // functype magic - try writer.writeByte(0x60); + try writer.writeByte(wasm.function_type); // param types try leb.writeULEB128(writer, @intCast(u32, ty.fnParamLen())); @@ -112,8 +138,8 @@ pub const Context = struct { defer self.gpa.free(params); ty.fnParamTypes(params); for (params) |param_type| { - const val_type = genValtype(param_type) orelse - return self.fail(self.decl.src(), "TODO: Wasm codegen - arg type value for type '{s}'", .{param_type.tag()}); + // Can we maybe get the source index of each param? + const val_type = try self.genValtype(self.decl.src(), param_type); try writer.writeByte(val_type); } } @@ -124,8 +150,8 @@ pub const Context = struct { .void, .noreturn => try leb.writeULEB128(writer, @as(u32, 0)), else => |ret_type| { try leb.writeULEB128(writer, @as(u32, 1)); - const val_type = genValtype(return_type) orelse - return self.fail(self.decl.src(), "TODO: Wasm codegen - return type value for type '{s}'", .{ret_type}); + // Can we maybe get the source index of the return type? + const val_type = try self.genValtype(self.decl.src(), return_type); try writer.writeByte(val_type); }, } @@ -137,40 +163,33 @@ pub const Context = struct { try self.genFunctype(); const writer = self.code.writer(); - // Reserve space to write the size after generating the code - try self.code.resize(5); + // Reserve space to write the size after generating the code as well as space for locals count + try self.code.resize(10); // Write instructions // TODO: check for and handle death of instructions const tv = self.decl.typed_value.most_recent.typed_value; const mod_fn = tv.val.castTag(.function).?.data; + try self.genBody(mod_fn.body); - var locals = std.ArrayList(u8).init(self.gpa); - defer locals.deinit(); - - for (mod_fn.body.instructions) |inst| { - if (inst.tag != .alloc) continue; - - const alloc: *Inst.NoOp = inst.castTag(.alloc).?; - const elem_type = alloc.base.ty.elemType(); - - const wasm_type = genValtype(elem_type) orelse - return self.fail(inst.src, "TODO: Wasm codegen - valtype for type '{s}'", .{elem_type.tag()}); - - try locals.append(wasm_type); - } + // finally, write our local types at the 'offset' position + { + leb.writeUnsignedFixed(5, self.code.items[5..10], @intCast(u32, self.locals.items.len)); - try leb.writeULEB128(writer, @intCast(u32, locals.items.len)); + // offset into 'code' section where we will put our locals types + var local_offset: usize = 10; - // emit the actual locals amount - for (locals.items) |local| { - try leb.writeULEB128(writer, @as(u32, 1)); - try leb.writeULEB128(writer, local); // valtype + // emit the actual locals amount + for (self.locals.items) |local| { + var buf: [6]u8 = undefined; + leb.writeUnsignedFixed(5, buf[0..5], @as(u32, 1)); + buf[5] = local; + try self.code.insertSlice(local_offset, &buf); + local_offset += 6; + } } - try self.genBody(mod_fn.body); - - try writer.writeByte(0x0B); // end + try writer.writeByte(wasm.opcode(.end)); // Fill in the size of the generated code to the reserved space at the // beginning of the buffer. @@ -183,10 +202,20 @@ pub const Context = struct { .add => self.genAdd(inst.castTag(.add).?), .alloc => self.genAlloc(inst.castTag(.alloc).?), .arg => self.genArg(inst.castTag(.arg).?), + .block => self.genBlock(inst.castTag(.block).?), + .br => self.genBr(inst.castTag(.br).?), .call => self.genCall(inst.castTag(.call).?), + .cmp_eq => self.genCmp(inst.castTag(.cmp_eq).?, .eq), + .cmp_gte => self.genCmp(inst.castTag(.cmp_gte).?, .gte), + .cmp_gt => self.genCmp(inst.castTag(.cmp_gt).?, .gt), + .cmp_lte => self.genCmp(inst.castTag(.cmp_lte).?, .lte), + .cmp_lt => self.genCmp(inst.castTag(.cmp_lt).?, .lt), + .cmp_neq => self.genCmp(inst.castTag(.cmp_neq).?, .neq), + .condbr => self.genCondBr(inst.castTag(.condbr).?), .constant => unreachable, .dbg_stmt => WValue.none, .load => self.genLoad(inst.castTag(.load).?), + .loop => self.genLoop(inst.castTag(.loop).?), .ret => self.genRet(inst.castTag(.ret).?), .retvoid => WValue.none, .store => self.genStore(inst.castTag(.store).?), @@ -197,7 +226,7 @@ pub const Context = struct { fn genBody(self: *Context, body: ir.Body) InnerError!void { for (body.instructions) |inst| { const result = try self.genInst(inst); - try self.values.putNoClobber(inst, result); + try self.values.putNoClobber(self.gpa, inst, result); } } @@ -205,7 +234,7 @@ pub const Context = struct { // TODO: Implement tail calls const operand = self.resolveInst(inst.operand); try self.emitWValue(operand); - return WValue.none; + return .none; } fn genCall(self: *Context, inst: *Inst.Call) InnerError!WValue { @@ -219,7 +248,7 @@ pub const Context = struct { try self.emitWValue(arg_val); } - try self.code.append(0x10); // call + try self.code.append(wasm.opcode(.call)); // The function index immediate argument will be filled in using this data // in link.Wasm.flush(). @@ -228,10 +257,14 @@ pub const Context = struct { .decl = target, }); - return WValue.none; + return .none; } fn genAlloc(self: *Context, inst: *Inst.NoOp) InnerError!WValue { + const elem_type = inst.base.ty.elemType(); + const valtype = try self.genValtype(inst.base.src, elem_type); + try self.locals.append(self.gpa, valtype); + defer self.local_index += 1; return WValue{ .local = self.local_index }; } @@ -243,15 +276,13 @@ pub const Context = struct { const rhs = self.resolveInst(inst.rhs); try self.emitWValue(rhs); - try writer.writeByte(0x21); // local.set + try writer.writeByte(wasm.opcode(.local_set)); try leb.writeULEB128(writer, lhs.local); - return WValue.none; + return .none; } fn genLoad(self: *Context, inst: *Inst.UnOp) InnerError!WValue { - const operand = self.resolveInst(inst.operand); - try self.emitWValue(operand); - return WValue.none; + return self.resolveInst(inst.operand); } fn genArg(self: *Context, inst: *Inst.Arg) InnerError!WValue { @@ -267,44 +298,44 @@ pub const Context = struct { try self.emitWValue(lhs); try self.emitWValue(rhs); - const opcode: u8 = switch (inst.base.ty.tag()) { - .u32, .i32 => 0x6A, //i32.add - .u64, .i64 => 0x7C, //i64.add - .f32 => 0x92, //f32.add - .f64 => 0xA0, //f64.add + const opcode: wasm.Opcode = switch (inst.base.ty.tag()) { + .u32, .i32 => .i32_add, + .u64, .i64 => .i64_add, + .f32 => .f32_add, + .f64 => .f64_add, else => return self.fail(inst.base.src, "TODO - Implement wasm genAdd for type '{s}'", .{inst.base.ty.tag()}), }; - try self.code.append(opcode); - return WValue.none; + try self.code.append(wasm.opcode(opcode)); + return .none; } fn emitConstant(self: *Context, inst: *Inst.Constant) InnerError!void { const writer = self.code.writer(); switch (inst.base.ty.tag()) { .u32 => { - try writer.writeByte(0x41); // i32.const + try writer.writeByte(wasm.opcode(.i32_const)); try leb.writeILEB128(writer, inst.val.toUnsignedInt()); }, .i32 => { - try writer.writeByte(0x41); // i32.const + try writer.writeByte(wasm.opcode(.i32_const)); try leb.writeILEB128(writer, inst.val.toSignedInt()); }, .u64 => { - try writer.writeByte(0x42); // i64.const + try writer.writeByte(wasm.opcode(.i64_const)); try leb.writeILEB128(writer, inst.val.toUnsignedInt()); }, .i64 => { - try writer.writeByte(0x42); // i64.const + try writer.writeByte(wasm.opcode(.i64_const)); try leb.writeILEB128(writer, inst.val.toSignedInt()); }, .f32 => { - try writer.writeByte(0x43); // f32.const + try writer.writeByte(wasm.opcode(.f32_const)); // TODO: enforce LE byte order try writer.writeAll(mem.asBytes(&inst.val.toFloat(f32))); }, .f64 => { - try writer.writeByte(0x44); // f64.const + try writer.writeByte(wasm.opcode(.f64_const)); // TODO: enforce LE byte order try writer.writeAll(mem.asBytes(&inst.val.toFloat(f64))); }, @@ -312,4 +343,172 @@ pub const Context = struct { else => |ty| return self.fail(inst.base.src, "Wasm TODO: emitConstant for type {s}", .{ty}), } } + + fn genBlock(self: *Context, block: *Inst.Block) InnerError!WValue { + const block_ty = try self.genBlockType(block.base.src, block.base.ty); + + try self.startBlock(.block, block_ty, null); + block.codegen = .{ + // we don't use relocs, so using `relocs` is illegal behaviour. + .relocs = undefined, + // Here we set the current block idx, so breaks know the depth to jump + // to when breaking out. + .mcv = @bitCast(AnyMCValue, WValue{ .block_idx = self.block_depth }), + }; + try self.genBody(block.body); + try self.endBlock(); + + return .none; + } + + /// appends a new wasm block to the code section and increases the `block_depth` by 1 + fn startBlock(self: *Context, block_type: wasm.Opcode, valtype: u8, with_offset: ?usize) !void { + self.block_depth += 1; + if (with_offset) |offset| { + try self.code.insert(offset, wasm.opcode(block_type)); + try self.code.insert(offset + 1, valtype); + } else { + try self.code.append(wasm.opcode(block_type)); + try self.code.append(valtype); + } + } + + /// Ends the current wasm block and decreases the `block_depth` by 1 + fn endBlock(self: *Context) !void { + try self.code.append(wasm.opcode(.end)); + self.block_depth -= 1; + } + + fn genLoop(self: *Context, loop: *Inst.Loop) InnerError!WValue { + const loop_ty = try self.genBlockType(loop.base.src, loop.base.ty); + + try self.startBlock(.loop, loop_ty, null); + try self.genBody(loop.body); + + // breaking to the index of a loop block will continue the loop instead + try self.code.append(wasm.opcode(.br)); + try leb.writeULEB128(self.code.writer(), @as(u32, 0)); + + try self.endBlock(); + + return .none; + } + + fn genCondBr(self: *Context, condbr: *Inst.CondBr) InnerError!WValue { + const condition = self.resolveInst(condbr.condition); + const writer = self.code.writer(); + + // TODO: Handle death instructions for then and else body + + // insert blocks at the position of `offset` so + // the condition can jump to it + const offset = condition.code_offset; + const block_ty = try self.genBlockType(condbr.base.src, condbr.base.ty); + try self.startBlock(.block, block_ty, offset); + + // we inserted the block in front of the condition + // so now check if condition matches. If not, break outside this block + // and continue with the then codepath + try writer.writeByte(wasm.opcode(.br_if)); + try leb.writeULEB128(writer, @as(u32, 0)); + + try self.genBody(condbr.else_body); + try self.endBlock(); + + // Outer block that matches the condition + try self.genBody(condbr.then_body); + + return .none; + } + + fn genCmp(self: *Context, inst: *Inst.BinOp, op: std.math.CompareOperator) InnerError!WValue { + const ty = inst.lhs.ty.tag(); + + // save offset, so potential conditions can insert blocks in front of + // the comparison that we can later jump back to + const offset = self.code.items.len; + + const lhs = self.resolveInst(inst.lhs); + const rhs = self.resolveInst(inst.rhs); + + try self.emitWValue(lhs); + try self.emitWValue(rhs); + + const opcode_maybe: ?wasm.Opcode = switch (op) { + .lt => @as(?wasm.Opcode, switch (ty) { + .i32 => .i32_lt_s, + .u32 => .i32_lt_u, + .i64 => .i64_lt_s, + .u64 => .i64_lt_u, + .f32 => .f32_lt, + .f64 => .f64_lt, + else => null, + }), + .lte => @as(?wasm.Opcode, switch (ty) { + .i32 => .i32_le_s, + .u32 => .i32_le_u, + .i64 => .i64_le_s, + .u64 => .i64_le_u, + .f32 => .f32_le, + .f64 => .f64_le, + else => null, + }), + .eq => @as(?wasm.Opcode, switch (ty) { + .i32, .u32 => .i32_eq, + .i64, .u64 => .i64_eq, + .f32 => .f32_eq, + .f64 => .f64_eq, + else => null, + }), + .gte => @as(?wasm.Opcode, switch (ty) { + .i32 => .i32_ge_s, + .u32 => .i32_ge_u, + .i64 => .i64_ge_s, + .u64 => .i64_ge_u, + .f32 => .f32_ge, + .f64 => .f64_ge, + else => null, + }), + .gt => @as(?wasm.Opcode, switch (ty) { + .i32 => .i32_gt_s, + .u32 => .i32_gt_u, + .i64 => .i64_gt_s, + .u64 => .i64_gt_u, + .f32 => .f32_gt, + .f64 => .f64_gt, + else => null, + }), + .neq => @as(?wasm.Opcode, switch (ty) { + .i32, .u32 => .i32_ne, + .i64, .u64 => .i64_ne, + .f32 => .f32_ne, + .f64 => .f64_ne, + else => null, + }), + }; + + const opcode = opcode_maybe orelse + return self.fail(inst.base.src, "TODO - Wasm genCmp for type '{s}' and operator '{s}'", .{ ty, @tagName(op) }); + + try self.code.append(wasm.opcode(opcode)); + return WValue{ .code_offset = offset }; + } + + fn genBr(self: *Context, br: *Inst.Br) InnerError!WValue { + // of operand has codegen bits we should break with a value + if (br.operand.ty.hasCodeGenBits()) { + const operand = self.resolveInst(br.operand); + try self.emitWValue(operand); + } + + // every block contains a `WValue` with its block index. + // We then determine how far we have to jump to it by substracting it from current block depth + const wvalue = @bitCast(WValue, br.block.codegen.mcv); + const idx: u32 = self.block_depth - wvalue.block_idx; + const writer = self.code.writer(); + try writer.writeByte(wasm.opcode(.br)); + try leb.writeULEB128(writer, idx); + + return .none; + } }; |