lib/Target/WebAssembly/WebAssemblyInstrControl.td - llvm - Git at Google

 //===- WebAssemblyInstrControl.td-WebAssembly control-flow ------*- tablegen -*-
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// WebAssembly control-flow code-gen constructs.
 ///
 //===----------------------------------------------------------------------===//

 let isBranch = 1, isTerminator = 1, hasCtrlDep = 1 in {
 // The condition operand is a boolean value which WebAssembly represents as i32.
 defm BR_IF : I<(outs), (ins bb_op:$dst, I32:$cond),
                (outs), (ins bb_op:$dst),
                [(brcond I32:$cond, bb:$dst)],
                 "br_if   \t$dst, $cond", "br_if   \t$dst", 0x0d>;
 let isCodeGenOnly = 1 in
 defm BR_UNLESS : I<(outs), (ins bb_op:$dst, I32:$cond),
                    (outs), (ins bb_op:$dst), []>;
 let isBarrier = 1 in
 defm BR   : NRI<(outs), (ins bb_op:$dst),
                 [(br bb:$dst)],
                 "br      \t$dst", 0x0c>;
 } // isBranch = 1, isTerminator = 1, hasCtrlDep = 1

 def : Pat<(brcond (i32 (setne I32:$cond, 0)), bb:$dst),
           (BR_IF bb_op:$dst, I32:$cond)>;
 def : Pat<(brcond (i32 (seteq I32:$cond, 0)), bb:$dst),
           (BR_UNLESS bb_op:$dst, I32:$cond)>;

 // A list of branch targets enclosed in {} and separated by comma.
 // Used by br_table only.
 def BrListAsmOperand : AsmOperandClass { let Name = "BrList"; }
 let OperandNamespace = "WebAssembly", OperandType = "OPERAND_BRLIST" in
 def brlist : Operand<i32> {
   let ParserMatchClass = BrListAsmOperand;
   let PrintMethod = "printBrList";
 }

 // TODO: SelectionDAG's lowering insists on using a pointer as the index for
 // jump tables, so in practice we don't ever use BR_TABLE_I64 in wasm32 mode
 // currently.
 let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
 defm BR_TABLE_I32 : I<(outs), (ins I32:$index, variable_ops),
                       (outs), (ins brlist:$brl),
                       [(WebAssemblybr_table I32:$index)],
                       "br_table \t$index", "br_table \t$brl",
                       0x0e>;
 defm BR_TABLE_I64 : I<(outs), (ins I64:$index, variable_ops),
                       (outs), (ins brlist:$brl),
                       [(WebAssemblybr_table I64:$index)],
                       "br_table \t$index", "br_table \t$brl",
                       0x0e>;
 } // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1

 // This is technically a control-flow instruction, since all it affects is the
 // IP.
 defm NOP : NRI<(outs), (ins), [], "nop", 0x01>;

 // Placemarkers to indicate the start or end of a block or loop scope.
 // These use/clobber VALUE_STACK to prevent them from being moved into the
 // middle of an expression tree.
 let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {
 defm BLOCK : NRI<(outs), (ins Signature:$sig), [], "block   \t$sig", 0x02>;
 defm LOOP  : NRI<(outs), (ins Signature:$sig), [], "loop    \t$sig", 0x03>;

 defm IF : I<(outs), (ins Signature:$sig, I32:$cond),
             (outs), (ins Signature:$sig),
             [], "if    \t$sig, $cond", "if    \t$sig", 0x04>;
 defm ELSE : NRI<(outs), (ins), [], "else", 0x05>;

 // END_BLOCK, END_LOOP, END_IF and END_FUNCTION are represented with the same
 // opcode in wasm.
 defm END_BLOCK : NRI<(outs), (ins), [], "end_block", 0x0b>;
 defm END_LOOP  : NRI<(outs), (ins), [], "end_loop", 0x0b>;
 defm END_IF    : NRI<(outs), (ins), [], "end_if", 0x0b>;
 // Generic instruction, for disassembler.
 let IsCanonical = 1 in
 defm END       : NRI<(outs), (ins), [], "end", 0x0b>;
 let isTerminator = 1, isBarrier = 1 in
 defm END_FUNCTION : NRI<(outs), (ins), [], "end_function", 0x0b>;
 } // Uses = [VALUE_STACK], Defs = [VALUE_STACK]

 multiclass RETURN<WebAssemblyRegClass vt> {
   defm RETURN_#vt : I<(outs), (ins vt:$val), (outs), (ins),
                       [(WebAssemblyreturn vt:$val)],
                       "return  \t$val", "return", 0x0f>;
   // Equivalent to RETURN_#vt, for use at the end of a function when wasm
   // semantics return by falling off the end of the block.
   let isCodeGenOnly = 1 in
   defm FALLTHROUGH_RETURN_#vt : I<(outs), (ins vt:$val), (outs), (ins), []>;
 }

 multiclass SIMD_RETURN<ValueType vt> {
   defm RETURN_#vt : I<(outs), (ins V128:$val), (outs), (ins),
                       [(WebAssemblyreturn (vt V128:$val))],
                       "return  \t$val", "return", 0x0f>,
                     Requires<[HasSIMD128]>;
   // Equivalent to RETURN_#vt, for use at the end of a function when wasm
   // semantics return by falling off the end of the block.
   let isCodeGenOnly = 1 in
   defm FALLTHROUGH_RETURN_#vt : I<(outs), (ins V128:$val), (outs), (ins),
                                   []>,
                                   Requires<[HasSIMD128]>;
 }

 let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {

 let isReturn = 1 in {
   defm "": RETURN<I32>;
   defm "": RETURN<I64>;
   defm "": RETURN<F32>;
   defm "": RETURN<F64>;
   defm "": RETURN<EXCEPT_REF>;
   defm "": SIMD_RETURN<v16i8>;
   defm "": SIMD_RETURN<v8i16>;
   defm "": SIMD_RETURN<v4i32>;
   defm "": SIMD_RETURN<v2i64>;
   defm "": SIMD_RETURN<v4f32>;
   defm "": SIMD_RETURN<v2f64>;

   defm RETURN_VOID : NRI<(outs), (ins), [(WebAssemblyreturn)], "return", 0x0f>;

   // This is to RETURN_VOID what FALLTHROUGH_RETURN_#vt is to RETURN_#vt.
   let isCodeGenOnly = 1 in
   defm FALLTHROUGH_RETURN_VOID : NRI<(outs), (ins), []>;
 } // isReturn = 1

 defm UNREACHABLE : NRI<(outs), (ins), [(trap)], "unreachable", 0x00>;
 } // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1

 //===----------------------------------------------------------------------===//
 // Exception handling instructions
 //===----------------------------------------------------------------------===//

 let Predicates = [HasExceptionHandling] in {

 // Throwing an exception: throw / rethrow
 let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
 defm THROW : I<(outs), (ins event_op:$tag, variable_ops),
                (outs), (ins event_op:$tag),
                [(WebAssemblythrow (WebAssemblywrapper texternalsym:$tag))],
                "throw   \t$tag", "throw   \t$tag", 0x08>;
 defm RETHROW : I<(outs), (ins EXCEPT_REF:$exn), (outs), (ins),
                  [], "rethrow \t$exn", "rethrow", 0x09>;
 // Pseudo instruction to be the lowering target of int_wasm_rethrow_in_catch
 // intrinsic. Will be converted to the real rethrow instruction later.
 let isPseudo = 1 in
 defm RETHROW_IN_CATCH : NRI<(outs), (ins), [(int_wasm_rethrow_in_catch)],
                             "rethrow_in_catch", 0>;
 } // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1

 // Region within which an exception is caught: try / end_try
 let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {
 defm TRY     : NRI<(outs), (ins Signature:$sig), [], "try     \t$sig", 0x06>;
 defm END_TRY : NRI<(outs), (ins), [], "end_try", 0x0b>;
 } // Uses = [VALUE_STACK], Defs = [VALUE_STACK]

 // Catching an exception: catch / extract_exception
 let hasCtrlDep = 1, hasSideEffects = 1 in
 defm CATCH : I<(outs EXCEPT_REF:$dst), (ins), (outs), (ins), [],
                "catch   \t$dst", "catch", 0x07>;

 // Querying / extracing exception: br_on_exn
 // br_on_exn queries an except_ref to see if it matches the corresponding
 // exception tag index. If true it branches to the given label and pushes the
 // corresponding argument values of the exception onto the stack.
 let isBranch = 1, isTerminator = 1, hasCtrlDep = 1 in
 defm BR_ON_EXN : I<(outs), (ins bb_op:$dst, event_op:$tag, EXCEPT_REF:$exn),
                    (outs), (ins bb_op:$dst, event_op:$tag), [],
                    "br_on_exn \t$dst, $tag, $exn", "br_on_exn \t$dst, $tag",
                    0x0a>;
 // This is a pseudo instruction that simulates popping a value from stack, which
 // has been pushed by br_on_exn
 let isCodeGenOnly = 1, hasSideEffects = 1 in
 defm EXTRACT_EXCEPTION_I32 : NRI<(outs I32:$dst), (ins),
                                  [(set I32:$dst, (int_wasm_extract_exception))],
                                  "extract_exception\t$dst">;

 // Pseudo instructions: cleanupret / catchret
 let isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,
     isPseudo = 1, isEHScopeReturn = 1 in {
   defm CLEANUPRET : NRI<(outs), (ins), [(cleanupret)], "cleanupret", 0>;
   defm CATCHRET : NRI<(outs), (ins bb_op:$dst, bb_op:$from),
                       [(catchret bb:$dst, bb:$from)], "catchret", 0>;
 } // isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,
   // isPseudo = 1, isEHScopeReturn = 1
 } // Predicates = [HasExceptionHandling]
	//===- WebAssemblyInstrControl.td-WebAssembly control-flow ------- tablegen --
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//
	///
	/// \file
	/// WebAssembly control-flow code-gen constructs.
	///
	//===----------------------------------------------------------------------===//

	let isBranch = 1, isTerminator = 1, hasCtrlDep = 1 in {
	// The condition operand is a boolean value which WebAssembly represents as i32.
	defm BR_IF : I<(outs), (ins bb_op:$dst, I32:$cond),
	(outs), (ins bb_op:$dst),
	[(brcond I32:$cond, bb:$dst)],
	"br_if \t$dst, $cond", "br_if \t$dst", 0x0d>;
	let isCodeGenOnly = 1 in
	defm BR_UNLESS : I<(outs), (ins bb_op:$dst, I32:$cond),
	(outs), (ins bb_op:$dst), []>;
	let isBarrier = 1 in
	defm BR : NRI<(outs), (ins bb_op:$dst),
	[(br bb:$dst)],
	"br \t$dst", 0x0c>;
	} // isBranch = 1, isTerminator = 1, hasCtrlDep = 1

	def : Pat<(brcond (i32 (setne I32:$cond, 0)), bb:$dst),
	(BR_IF bb_op:$dst, I32:$cond)>;
	def : Pat<(brcond (i32 (seteq I32:$cond, 0)), bb:$dst),
	(BR_UNLESS bb_op:$dst, I32:$cond)>;

	// A list of branch targets enclosed in {} and separated by comma.
	// Used by br_table only.
	def BrListAsmOperand : AsmOperandClass { let Name = "BrList"; }
	let OperandNamespace = "WebAssembly", OperandType = "OPERAND_BRLIST" in
	def brlist : Operand<i32> {
	let ParserMatchClass = BrListAsmOperand;
	let PrintMethod = "printBrList";
	}

	// TODO: SelectionDAG's lowering insists on using a pointer as the index for
	// jump tables, so in practice we don't ever use BR_TABLE_I64 in wasm32 mode
	// currently.
	let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
	defm BR_TABLE_I32 : I<(outs), (ins I32:$index, variable_ops),
	(outs), (ins brlist:$brl),
	[(WebAssemblybr_table I32:$index)],
	"br_table \t$index", "br_table \t$brl",
	0x0e>;
	defm BR_TABLE_I64 : I<(outs), (ins I64:$index, variable_ops),
	(outs), (ins brlist:$brl),
	[(WebAssemblybr_table I64:$index)],
	"br_table \t$index", "br_table \t$brl",
	0x0e>;
	} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1

	// This is technically a control-flow instruction, since all it affects is the
	// IP.
	defm NOP : NRI<(outs), (ins), [], "nop", 0x01>;

	// Placemarkers to indicate the start or end of a block or loop scope.
	// These use/clobber VALUE_STACK to prevent them from being moved into the
	// middle of an expression tree.
	let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {
	defm BLOCK : NRI<(outs), (ins Signature:$sig), [], "block \t$sig", 0x02>;
	defm LOOP : NRI<(outs), (ins Signature:$sig), [], "loop \t$sig", 0x03>;

	defm IF : I<(outs), (ins Signature:$sig, I32:$cond),
	(outs), (ins Signature:$sig),
	[], "if \t$sig, $cond", "if \t$sig", 0x04>;
	defm ELSE : NRI<(outs), (ins), [], "else", 0x05>;

	// END_BLOCK, END_LOOP, END_IF and END_FUNCTION are represented with the same
	// opcode in wasm.
	defm END_BLOCK : NRI<(outs), (ins), [], "end_block", 0x0b>;
	defm END_LOOP : NRI<(outs), (ins), [], "end_loop", 0x0b>;
	defm END_IF : NRI<(outs), (ins), [], "end_if", 0x0b>;
	// Generic instruction, for disassembler.
	let IsCanonical = 1 in
	defm END : NRI<(outs), (ins), [], "end", 0x0b>;
	let isTerminator = 1, isBarrier = 1 in
	defm END_FUNCTION : NRI<(outs), (ins), [], "end_function", 0x0b>;
	} // Uses = [VALUE_STACK], Defs = [VALUE_STACK]

	multiclass RETURN<WebAssemblyRegClass vt> {
	defm RETURN_#vt : I<(outs), (ins vt:$val), (outs), (ins),
	[(WebAssemblyreturn vt:$val)],
	"return \t$val", "return", 0x0f>;
	// Equivalent to RETURN_#vt, for use at the end of a function when wasm
	// semantics return by falling off the end of the block.
	let isCodeGenOnly = 1 in
	defm FALLTHROUGH_RETURN_#vt : I<(outs), (ins vt:$val), (outs), (ins), []>;
	}

	multiclass SIMD_RETURN<ValueType vt> {
	defm RETURN_#vt : I<(outs), (ins V128:$val), (outs), (ins),
	[(WebAssemblyreturn (vt V128:$val))],
	"return \t$val", "return", 0x0f>,
	Requires<[HasSIMD128]>;
	// Equivalent to RETURN_#vt, for use at the end of a function when wasm
	// semantics return by falling off the end of the block.
	let isCodeGenOnly = 1 in
	defm FALLTHROUGH_RETURN_#vt : I<(outs), (ins V128:$val), (outs), (ins),
	[]>,
	Requires<[HasSIMD128]>;
	}

	let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {

	let isReturn = 1 in {
	defm "": RETURN<I32>;
	defm "": RETURN<I64>;
	defm "": RETURN<F32>;
	defm "": RETURN<F64>;
	defm "": RETURN<EXCEPT_REF>;
	defm "": SIMD_RETURN<v16i8>;
	defm "": SIMD_RETURN<v8i16>;
	defm "": SIMD_RETURN<v4i32>;
	defm "": SIMD_RETURN<v2i64>;
	defm "": SIMD_RETURN<v4f32>;
	defm "": SIMD_RETURN<v2f64>;

	defm RETURN_VOID : NRI<(outs), (ins), [(WebAssemblyreturn)], "return", 0x0f>;

	// This is to RETURN_VOID what FALLTHROUGH_RETURN_#vt is to RETURN_#vt.
	let isCodeGenOnly = 1 in
	defm FALLTHROUGH_RETURN_VOID : NRI<(outs), (ins), []>;
	} // isReturn = 1

	defm UNREACHABLE : NRI<(outs), (ins), [(trap)], "unreachable", 0x00>;
	} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1

	//===----------------------------------------------------------------------===//
	// Exception handling instructions
	//===----------------------------------------------------------------------===//

	let Predicates = [HasExceptionHandling] in {

	// Throwing an exception: throw / rethrow
	let isTerminator = 1, hasCtrlDep = 1, isBarrier = 1 in {
	defm THROW : I<(outs), (ins event_op:$tag, variable_ops),
	(outs), (ins event_op:$tag),
	[(WebAssemblythrow (WebAssemblywrapper texternalsym:$tag))],
	"throw \t$tag", "throw \t$tag", 0x08>;
	defm RETHROW : I<(outs), (ins EXCEPT_REF:$exn), (outs), (ins),
	[], "rethrow \t$exn", "rethrow", 0x09>;
	// Pseudo instruction to be the lowering target of int_wasm_rethrow_in_catch
	// intrinsic. Will be converted to the real rethrow instruction later.
	let isPseudo = 1 in
	defm RETHROW_IN_CATCH : NRI<(outs), (ins), [(int_wasm_rethrow_in_catch)],
	"rethrow_in_catch", 0>;
	} // isTerminator = 1, hasCtrlDep = 1, isBarrier = 1

	// Region within which an exception is caught: try / end_try
	let Uses = [VALUE_STACK], Defs = [VALUE_STACK] in {
	defm TRY : NRI<(outs), (ins Signature:$sig), [], "try \t$sig", 0x06>;
	defm END_TRY : NRI<(outs), (ins), [], "end_try", 0x0b>;
	} // Uses = [VALUE_STACK], Defs = [VALUE_STACK]

	// Catching an exception: catch / extract_exception
	let hasCtrlDep = 1, hasSideEffects = 1 in
	defm CATCH : I<(outs EXCEPT_REF:$dst), (ins), (outs), (ins), [],
	"catch \t$dst", "catch", 0x07>;

	// Querying / extracing exception: br_on_exn
	// br_on_exn queries an except_ref to see if it matches the corresponding
	// exception tag index. If true it branches to the given label and pushes the
	// corresponding argument values of the exception onto the stack.
	let isBranch = 1, isTerminator = 1, hasCtrlDep = 1 in
	defm BR_ON_EXN : I<(outs), (ins bb_op:$dst, event_op:$tag, EXCEPT_REF:$exn),
	(outs), (ins bb_op:$dst, event_op:$tag), [],
	"br_on_exn \t$dst, $tag, $exn", "br_on_exn \t$dst, $tag",
	0x0a>;
	// This is a pseudo instruction that simulates popping a value from stack, which
	// has been pushed by br_on_exn
	let isCodeGenOnly = 1, hasSideEffects = 1 in
	defm EXTRACT_EXCEPTION_I32 : NRI<(outs I32:$dst), (ins),
	[(set I32:$dst, (int_wasm_extract_exception))],
	"extract_exception\t$dst">;

	// Pseudo instructions: cleanupret / catchret
	let isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,
	isPseudo = 1, isEHScopeReturn = 1 in {
	defm CLEANUPRET : NRI<(outs), (ins), [(cleanupret)], "cleanupret", 0>;
	defm CATCHRET : NRI<(outs), (ins bb_op:$dst, bb_op:$from),
	[(catchret bb:$dst, bb:$from)], "catchret", 0>;
	} // isTerminator = 1, hasSideEffects = 1, isBarrier = 1, hasCtrlDep = 1,
	// isPseudo = 1, isEHScopeReturn = 1
	} // Predicates = [HasExceptionHandling]