1//===- WebAssemblyInstrControl.td-WebAssembly control-flow ------*- tablegen -*-
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9///
10/// \file
11/// \brief WebAssembly control-flow code-gen constructs.
12///
13//===----------------------------------------------------------------------===//
14
15/*
16 * TODO(jfb): Add the following.
17 *
18 * block: a fixed-length sequence of statements
19 * if: if statement
20 * do_while: do while statement, basically a loop with a conditional branch
21 * forever: infinite loop statement (like while (1)), basically an unconditional
22 *          branch (back to the top of the loop)
23 * continue: continue to start of nested loop
24 * break: break to end from nested loop or block
25 * switch: switch statement with fallthrough
26 */
27
28let isBranch = 1, isTerminator = 1, hasCtrlDep = 1 in {
29def BR_IF_ : I<(outs), (ins bb_op:$dst, I32:$a),
30               [(brcond I32:$a, bb:$dst)],
31               "br_if $dst, $a">;
32let isBarrier = 1 in {
33def BR   : I<(outs), (ins bb_op:$dst),
34             [(br bb:$dst)],
35             "br $dst">;
36} // isBarrier = 1
37} // isBranch = 1, isTerminator = 1, hasCtrlDep = 1
38
39// TODO: SelectionDAG's lowering insists on using a pointer as the index for
40// jump tables, so in practice we don't ever use SWITCH_I64 in wasm32 mode
41// currently.
42let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
43def SWITCH_I32 : I<(outs), (ins I32:$index, variable_ops),
44                   [(WebAssemblyswitch I32:$index)]>;
45def SWITCH_I64 : I<(outs), (ins I64:$index, variable_ops),
46                   [(WebAssemblyswitch I64:$index)]>;
47} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1
48
49// Placemarkers to indicate the start of a block or loop scope.
50def BLOCK     : I<(outs), (ins bb_op:$dst), [], "block $dst">;
51def LOOP      : I<(outs), (ins bb_op:$dst), [], "loop $dst">;
52
53multiclass RETURN<WebAssemblyRegClass vt> {
54  def RETURN_#vt : I<(outs), (ins vt:$val), [(WebAssemblyreturn vt:$val)],
55                     "return $val">;
56}
57
58let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
59let isReturn = 1 in {
60  defm : RETURN<I32>;
61  defm : RETURN<I64>;
62  defm : RETURN<F32>;
63  defm : RETURN<F64>;
64  def RETURN_VOID : I<(outs), (ins), [(WebAssemblyreturn)], "return">;
65} // isReturn = 1
66  def UNREACHABLE : I<(outs), (ins), [(trap)], "unreachable">;
67} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1
68