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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-exception6//7//===----------------------------------------------------------------------===//8///9/// \file10/// 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 in21defm BR_UNLESS : I<(outs), (ins bb_op:$dst, I32:$cond),22 (outs), (ins bb_op:$dst), []>;23let isBarrier = 1 in24defm BR : NRI<(outs), (ins bb_op:$dst),25 [(br bb:$dst)],26 "br \t$dst", 0x0c>;27} // isBranch = 1, isTerminator = 1, hasCtrlDep = 128 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)>;33def : Pat<(brcond (i32 (xor bool_node:$cond, (i32 1))), bb:$dst),34 (BR_UNLESS bb_op:$dst, I32:$cond)>;35 36// A list of branch targets enclosed in {} and separated by comma.37// Used by br_table only.38def BrListAsmOperand : AsmOperandClass { let Name = "BrList"; }39let OperandNamespace = "WebAssembly", OperandType = "OPERAND_BRLIST" in40def brlist : Operand<i32> {41 let ParserMatchClass = BrListAsmOperand;42 let PrintMethod = "printBrList";43}44 45// Duplicating a BR_TABLE is almost never a good idea. In particular, it can46// lead to some nasty irreducibility due to tail merging when the br_table is in47// a loop.48let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1, isNotDuplicable = 1 in {49 50defm BR_TABLE_I32 : I<(outs), (ins I32:$index, variable_ops),51 (outs), (ins brlist:$brl),52 [(WebAssemblybr_table I32:$index)],53 "br_table \t$index", "br_table \t$brl",54 0x0e>;55// TODO: SelectionDAG's lowering insists on using a pointer as the index for56// jump tables, so in practice we don't ever use BR_TABLE_I64 in wasm32 mode57// currently.58defm BR_TABLE_I64 : I<(outs), (ins I64:$index, variable_ops),59 (outs), (ins brlist:$brl),60 [(WebAssemblybr_table I64:$index)],61 "br_table \t$index", "br_table \t$brl",62 0x0e>;63} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1, isNotDuplicable = 164 65// This is technically a control-flow instruction, since all it affects is the66// IP.67defm NOP : NRI<(outs), (ins), [], "nop", 0x01>;68 69// Placemarkers to indicate the start or end of a block or loop scope.70// These use/clobber VALUE_STACK to prevent them from being moved into the71// middle of an expression tree.72let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {73defm BLOCK : NRI<(outs), (ins Signature:$sig), [], "block \t$sig", 0x02>;74defm LOOP : NRI<(outs), (ins Signature:$sig), [], "loop \t$sig", 0x03>;75 76defm IF : I<(outs), (ins Signature:$sig, I32:$cond),77 (outs), (ins Signature:$sig),78 [], "if \t$sig, $cond", "if \t$sig", 0x04>;79defm ELSE : NRI<(outs), (ins), [], "else", 0x05>;80 81// END_BLOCK, END_LOOP, END_IF and END_FUNCTION are represented with the same82// opcode in wasm.83defm END_BLOCK : NRI<(outs), (ins), [], "end_block", 0x0b>;84defm END_LOOP : NRI<(outs), (ins), [], "end_loop", 0x0b>;85defm END_IF : NRI<(outs), (ins), [], "end_if", 0x0b>;86// Generic instruction, for disassembler.87let IsCanonical = 1 in88defm END : NRI<(outs), (ins), [], "end", 0x0b>;89let isTerminator = 1, isBarrier = 1 in90defm END_FUNCTION : NRI<(outs), (ins), [], "end_function", 0x0b>;91} // Uses = [VALUE_STACK], Defs = [VALUE_STACK]92 93 94let hasCtrlDep = 1, isBarrier = 1 in {95let isTerminator = 1 in {96let isReturn = 1 in {97 98defm RETURN : I<(outs), (ins variable_ops), (outs), (ins),99 [(WebAssemblyreturn)],100 "return", "return", 0x0f>;101// Equivalent to RETURN, for use at the end of a function when wasm102// semantics return by falling off the end of the block.103let isCodeGenOnly = 1 in104defm FALLTHROUGH_RETURN : I<(outs), (ins variable_ops), (outs), (ins), []>;105 106} // isReturn = 1107 108let IsCanonical = 1, isTrap = 1 in109defm UNREACHABLE : NRI<(outs), (ins), [(trap)], "unreachable", 0x00>;110 111} // isTerminator = 1112 113// debugtrap explicitly returns despite trapping because it is supposed to just114// get the attention of the debugger. Unfortunately, because UNREACHABLE is a115// terminator, lowering debugtrap to UNREACHABLE can create an invalid116// MachineBasicBlock when there is additional code after it. Lower it to this117// non-terminator version instead.118// TODO: Actually execute the debugger statement when running on the Web119let isTrap = 1 in120defm DEBUG_UNREACHABLE : NRI<(outs), (ins), [(debugtrap)], "unreachable", 0x00>;121 122} // hasCtrlDep = 1, isBarrier = 1123 124//===----------------------------------------------------------------------===//125// Exception handling instructions126//===----------------------------------------------------------------------===//127 128// A list of catch clauses attached to try_table.129def CatchListAsmOperand : AsmOperandClass { let Name = "CatchList"; }130let OperandNamespace = "WebAssembly", OperandType = "OPERAND_CATCH_LIST" in131def catch_list : Operand<i32> {132 let ParserMatchClass = CatchListAsmOperand;133 let PrintMethod = "printCatchList";134}135 136let Predicates = [HasExceptionHandling] in {137 138// Throwing an exception: throw / throw_ref139let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {140defm THROW : I<(outs), (ins tag_op:$tag, variable_ops),141 (outs), (ins tag_op:$tag), [],142 "throw \t$tag", "throw \t$tag", 0x08>;143defm THROW_REF : I<(outs), (ins EXNREF:$exn), (outs), (ins), [],144 "throw_ref \t$exn", "throw_ref", 0x0a>;145} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1146 147// Region within which an exception is caught: try_table / end_try_table148let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {149defm TRY_TABLE : I<(outs), (ins Signature:$sig, variable_ops),150 (outs), (ins Signature:$sig, catch_list:$cal), [],151 "try_table \t$sig", "try_table \t$sig $cal", 0x1f>;152defm END_TRY_TABLE : NRI<(outs), (ins), [], "end_try_table", 0x0b>;153} // Uses = [VALUE_STACK], Defs = [VALUE_STACK]154 155// Pseudo instructions that represent catch / catch_ref / catch_all /156// catch_all_ref clauses in a try_table instruction.157let hasCtrlDep = 1, hasSideEffects = 1, isCodeGenOnly = 1 in {158let variadicOpsAreDefs = 1 in {159defm CATCH : I<(outs), (ins tag_op:$tag, variable_ops),160 (outs), (ins tag_op:$tag), []>;161defm CATCH_REF : I<(outs), (ins tag_op:$tag, variable_ops),162 (outs), (ins tag_op:$tag), []>;163}164defm CATCH_ALL : NRI<(outs), (ins), []>;165defm CATCH_ALL_REF : I<(outs EXNREF:$dst), (ins), (outs), (ins), []>;166}167 168// Pseudo instructions: cleanupret / catchret169let isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,170 isPseudo = 1, isEHScopeReturn = 1 in {171 defm CLEANUPRET : NRI<(outs), (ins bb_op:$ehpad), [(cleanupret bb:$ehpad)],172 "cleanupret", 0>;173 defm CATCHRET : NRI<(outs), (ins bb_op:$dst, bb_op:$from),174 [(catchret bb:$dst, bb:$from)], "catchret", 0>;175} // isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,176 // isPseudo = 1, isEHScopeReturn = 1177 178// Below are instructions from the legacy EH proposal. Could be deprecated if179// usage gets low enough.180 181// Rethrowing an exception: rethrow182// The new exnref proposal also uses this instruction as an interim pseudo183// instruction before we convert it to a THROW_REF.184// $ehpad is the EH pad where the exception to rethrow has been caught.185let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in186defm RETHROW : NRI<(outs), (ins bb_op:$ehpad), [], "rethrow \t$ehpad", 0x09>;187 188// Region within which an exception is caught: try / end_try189let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {190defm TRY : NRI<(outs), (ins Signature:$sig), [], "try \t$sig", 0x06>;191defm END_TRY : NRI<(outs), (ins), [], "end_try", 0x0b>;192} // Uses = [VALUE_STACK], Defs = [VALUE_STACK]193 194// Catching an exception: catch / catch_all195let hasCtrlDep = 1, hasSideEffects = 1 in {196let variadicOpsAreDefs = 1 in197defm CATCH_LEGACY : I<(outs), (ins tag_op:$tag, variable_ops),198 (outs), (ins tag_op:$tag), [],199 "catch", "catch \t$tag", 0x07>;200defm CATCH_ALL_LEGACY : NRI<(outs), (ins), [], "catch_all", 0x19>;201}202 203// Delegating an exception: delegate204let isTerminator = 1, hasCtrlDep = 1, hasSideEffects = 1 in205defm DELEGATE : NRI<(outs), (ins bb_op:$dst), [], "delegate \t $dst", 0x18>;206 207} // Predicates = [HasExceptionHandling]208