WebAssemblyInstrControl.td revision 355940 
1//===- WebAssemblyInstrControl.td-WebAssembly control-flow ------*- tablegen -*-
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// WebAssembly control-flow code-gen constructs.
11///
12//===----------------------------------------------------------------------===//
13
14let isBranch = 1, isTerminator = 1, hasCtrlDep = 1 in {
15// The condition operand is a boolean value which WebAssembly represents as i32.
16defm BR_IF : I<(outs), (ins bb_op:$dst, I32:$cond),
17               (outs), (ins bb_op:$dst),
18               [(brcond I32:$cond, bb:$dst)],
19                "br_if   \t$dst, $cond", "br_if   \t$dst", 0x0d>;
20let isCodeGenOnly = 1 in
21defm BR_UNLESS : I<(outs), (ins bb_op:$dst, I32:$cond),
22                   (outs), (ins bb_op:$dst), []>;
23let isBarrier = 1 in
24defm BR   : NRI<(outs), (ins bb_op:$dst),
25                [(br bb:$dst)],
26                "br      \t$dst", 0x0c>;
27} // isBranch = 1, isTerminator = 1, hasCtrlDep = 1
28
29def : Pat<(brcond (i32 (setne I32:$cond, 0)), bb:$dst),
30          (BR_IF bb_op:$dst, I32:$cond)>;
31def : Pat<(brcond (i32 (seteq I32:$cond, 0)), bb:$dst),
32          (BR_UNLESS bb_op:$dst, I32:$cond)>;
33
34// A list of branch targets enclosed in {} and separated by comma.
35// Used by br_table only.
36def BrListAsmOperand : AsmOperandClass { let Name = "BrList"; }
37let OperandNamespace = "WebAssembly", OperandType = "OPERAND_BRLIST" in
38def brlist : Operand<i32> {
39  let ParserMatchClass = BrListAsmOperand;
40  let PrintMethod = "printBrList";
41}
42
43// TODO: SelectionDAG's lowering insists on using a pointer as the index for
44// jump tables, so in practice we don't ever use BR_TABLE_I64 in wasm32 mode
45// currently.
46let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
47defm BR_TABLE_I32 : I<(outs), (ins I32:$index, variable_ops),
48                      (outs), (ins brlist:$brl),
49                      [(WebAssemblybr_table I32:$index)],
50                      "br_table \t$index", "br_table \t$brl",
51                      0x0e>;
52defm BR_TABLE_I64 : I<(outs), (ins I64:$index, variable_ops),
53                      (outs), (ins brlist:$brl),
54                      [(WebAssemblybr_table I64:$index)],
55                      "br_table \t$index", "br_table \t$brl",
56                      0x0e>;
57} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1
58
59// This is technically a control-flow instruction, since all it affects is the
60// IP.
61defm NOP : NRI<(outs), (ins), [], "nop", 0x01>;
62
63// Placemarkers to indicate the start or end of a block or loop scope.
64// These use/clobber VALUE_STACK to prevent them from being moved into the
65// middle of an expression tree.
66let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {
67defm BLOCK : NRI<(outs), (ins Signature:$sig), [], "block   \t$sig", 0x02>;
68defm LOOP  : NRI<(outs), (ins Signature:$sig), [], "loop    \t$sig", 0x03>;
69
70defm IF : I<(outs), (ins Signature:$sig, I32:$cond),
71            (outs), (ins Signature:$sig),
72            [], "if    \t$sig, $cond", "if    \t$sig", 0x04>;
73defm ELSE : NRI<(outs), (ins), [], "else", 0x05>;
74
75// END_BLOCK, END_LOOP, END_IF and END_FUNCTION are represented with the same
76// opcode in wasm.
77defm END_BLOCK : NRI<(outs), (ins), [], "end_block", 0x0b>;
78defm END_LOOP  : NRI<(outs), (ins), [], "end_loop", 0x0b>;
79defm END_IF    : NRI<(outs), (ins), [], "end_if", 0x0b>;
80// Generic instruction, for disassembler.
81let IsCanonical = 1 in
82defm END       : NRI<(outs), (ins), [], "end", 0x0b>;
83let isTerminator = 1, isBarrier = 1 in
84defm END_FUNCTION : NRI<(outs), (ins), [], "end_function", 0x0b>;
85} // Uses = [VALUE_STACK], Defs = [VALUE_STACK]
86
87multiclass RETURN<WebAssemblyRegClass vt> {
88  defm RETURN_#vt : I<(outs), (ins vt:$val), (outs), (ins),
89                      [(WebAssemblyreturn vt:$val)],
90                      "return  \t$val", "return", 0x0f>;
91  // Equivalent to RETURN_#vt, for use at the end of a function when wasm
92  // semantics return by falling off the end of the block.
93  let isCodeGenOnly = 1 in
94  defm FALLTHROUGH_RETURN_#vt : I<(outs), (ins vt:$val), (outs), (ins), []>;
95}
96
97multiclass SIMD_RETURN<ValueType vt> {
98  defm RETURN_#vt : I<(outs), (ins V128:$val), (outs), (ins),
99                      [(WebAssemblyreturn (vt V128:$val))],
100                      "return  \t$val", "return", 0x0f>,
101                    Requires<[HasSIMD128]>;
102  // Equivalent to RETURN_#vt, for use at the end of a function when wasm
103  // semantics return by falling off the end of the block.
104  let isCodeGenOnly = 1 in
105  defm FALLTHROUGH_RETURN_#vt : I<(outs), (ins V128:$val), (outs), (ins),
106                                  []>,
107                                  Requires<[HasSIMD128]>;
108}
109
110let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
111
112let isReturn = 1 in {
113  defm "": RETURN<I32>;
114  defm "": RETURN<I64>;
115  defm "": RETURN<F32>;
116  defm "": RETURN<F64>;
117  defm "": RETURN<EXNREF>;
118  defm "": SIMD_RETURN<v16i8>;
119  defm "": SIMD_RETURN<v8i16>;
120  defm "": SIMD_RETURN<v4i32>;
121  defm "": SIMD_RETURN<v2i64>;
122  defm "": SIMD_RETURN<v4f32>;
123  defm "": SIMD_RETURN<v2f64>;
124
125  defm RETURN_VOID : NRI<(outs), (ins), [(WebAssemblyreturn)], "return", 0x0f>;
126
127  // This is to RETURN_VOID what FALLTHROUGH_RETURN_#vt is to RETURN_#vt.
128  let isCodeGenOnly = 1 in
129  defm FALLTHROUGH_RETURN_VOID : NRI<(outs), (ins), []>;
130} // isReturn = 1
131
132defm UNREACHABLE : NRI<(outs), (ins), [(trap)], "unreachable", 0x00>;
133} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1
134
135//===----------------------------------------------------------------------===//
136// Exception handling instructions
137//===----------------------------------------------------------------------===//
138
139let Predicates = [HasExceptionHandling] in {
140
141// Throwing an exception: throw / rethrow
142let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
143defm THROW : I<(outs), (ins event_op:$tag, variable_ops),
144               (outs), (ins event_op:$tag),
145               [(WebAssemblythrow (WebAssemblywrapper texternalsym:$tag))],
146               "throw   \t$tag", "throw   \t$tag", 0x08>;
147defm RETHROW : I<(outs), (ins EXNREF:$exn), (outs), (ins), [],
148                 "rethrow \t$exn", "rethrow", 0x09>;
149// Pseudo instruction to be the lowering target of int_wasm_rethrow_in_catch
150// intrinsic. Will be converted to the real rethrow instruction later.
151let isPseudo = 1 in
152defm RETHROW_IN_CATCH : NRI<(outs), (ins), [(int_wasm_rethrow_in_catch)],
153                            "rethrow_in_catch", 0>;
154} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1
155
156// Region within which an exception is caught: try / end_try
157let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {
158defm TRY     : NRI<(outs), (ins Signature:$sig), [], "try     \t$sig", 0x06>;
159defm END_TRY : NRI<(outs), (ins), [], "end_try", 0x0b>;
160} // Uses = [VALUE_STACK], Defs = [VALUE_STACK]
161
162// Catching an exception: catch / extract_exception
163let hasCtrlDep = 1, hasSideEffects = 1 in
164defm CATCH : I<(outs EXNREF:$dst), (ins), (outs), (ins), [],
165               "catch   \t$dst", "catch", 0x07>;
166
167// Querying / extracing exception: br_on_exn
168// br_on_exn queries an exnref to see if it matches the corresponding exception
169// tag index. If true it branches to the given label and pushes the
170// corresponding argument values of the exception onto the stack.
171let isBranch = 1, isTerminator = 1, hasCtrlDep = 1 in
172defm BR_ON_EXN : I<(outs), (ins bb_op:$dst, event_op:$tag, EXNREF:$exn),
173                   (outs), (ins bb_op:$dst, event_op:$tag), [],
174                   "br_on_exn \t$dst, $tag, $exn", "br_on_exn \t$dst, $tag",
175                   0x0a>;
176// This is a pseudo instruction that simulates popping a value from stack, which
177// has been pushed by br_on_exn
178let isCodeGenOnly = 1, hasSideEffects = 1 in
179defm EXTRACT_EXCEPTION_I32 : NRI<(outs I32:$dst), (ins),
180                                 [(set I32:$dst, (int_wasm_extract_exception))],
181                                 "extract_exception\t$dst">;
182
183// Pseudo instructions: cleanupret / catchret
184let isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,
185    isPseudo = 1, isEHScopeReturn = 1 in {
186  defm CLEANUPRET : NRI<(outs), (ins), [(cleanupret)], "cleanupret", 0>;
187  defm CATCHRET : NRI<(outs), (ins bb_op:$dst, bb_op:$from),
188                      [(catchret bb:$dst, bb:$from)], "catchret", 0>;
189} // isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,
190  // isPseudo = 1, isEHScopeReturn = 1
191} // Predicates = [HasExceptionHandling]
192