[WebAssembly,llvm] Add llvm.wasm.ref.test.func intrinsic

llvm/include/llvm/IR/IntrinsicsWebAssembly.td

@@ -43,6 +43,10 @@ def int_wasm_ref_is_null_exn :
   DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_exnref_ty], [IntrNoMem],
                         "llvm.wasm.ref.is_null.exn">;
 
+def int_wasm_ref_test_func
+    : DefaultAttrsIntrinsic<[llvm_i32_ty], [llvm_ptr_ty, llvm_vararg_ty],
+                            [IntrNoMem], "llvm.wasm.ref.test.func">;
+
 //===----------------------------------------------------------------------===//
 // Table intrinsics
 //===----------------------------------------------------------------------===//

llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp

@@ -18,6 +18,7 @@
 #include "WebAssemblySubtarget.h"
 #include "WebAssemblyTargetMachine.h"
 #include "WebAssemblyUtilities.h"
+#include "llvm/BinaryFormat/Wasm.h"
 #include "llvm/CodeGen/CallingConvLower.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
@@ -501,6 +502,51 @@ MVT WebAssemblyTargetLowering::getScalarShiftAmountTy(const DataLayout & /*DL*/,
   return Result;
 }
 
+static MachineBasicBlock *LowerRefTestFuncRef(MachineInstr &MI, DebugLoc DL,
+                                              MachineBasicBlock *BB,
+                                              const TargetInstrInfo &TII) {
+  // Lower a REF_TEST_FUNCREF_PSEUDO instruction into a REF_TEST_FUNCREF
+  // instruction by combining the signature info Imm operands that
+  // SelectionDag/InstrEmitter.cpp makes into one CImm operand. Put this into
+  // the type index placeholder for REF_TEST_FUNCREF
+  Register ResultReg = MI.getOperand(0).getReg();
+  Register FuncRefReg = MI.getOperand(1).getReg();
+
+  auto NParams = MI.getNumOperands() - 3;
+  auto Sig = APInt(NParams * 64, 0);
+
+  {
+    uint64_t V = MI.getOperand(2).getImm();
+    Sig |= int64_t(V);
+  }
+
+  for (unsigned I = 3; I < MI.getNumOperands(); I++) {
+    const MachineOperand &MO = MI.getOperand(I);
+    if (!MO.isImm()) {
+      // I'm not really sure what these are or where they come from but it seems
+      // to be okay to ignore them
+      continue;
+    }
+    uint16_t V = MO.getImm();
+    Sig <<= 64;
+    Sig |= int64_t(V);
+  }
+
+  ConstantInt *TypeInfo =
+      ConstantInt::get(BB->getParent()->getFunction().getContext(), Sig);
+
+  // Put the type info first in the placeholder for the type index, then the
+  // actual funcref arg
+  BuildMI(*BB, MI, DL, TII.get(WebAssembly::REF_TEST_FUNCREF), ResultReg)
+      .addCImm(TypeInfo)
+      .addReg(FuncRefReg);
+
+  // Remove the original instruction
+  MI.eraseFromParent();
+
+  return BB;
+}
+
 // Lower an fp-to-int conversion operator from the LLVM opcode, which has an
 // undefined result on invalid/overflow, to the WebAssembly opcode, which
 // traps on invalid/overflow.
@@ -794,6 +840,7 @@ LowerCallResults(MachineInstr &CallResults, DebugLoc DL, MachineBasicBlock *BB,
 
   if (IsIndirect) {
     // Placeholder for the type index.
+    // This gets replaced with the correct value in WebAssemblyMCInstLower.cpp
     MIB.addImm(0);
     // The table into which this call_indirect indexes.
     MCSymbolWasm *Table = IsFuncrefCall
@@ -862,6 +909,8 @@ MachineBasicBlock *WebAssemblyTargetLowering::EmitInstrWithCustomInserter(
   switch (MI.getOpcode()) {
   default:
     llvm_unreachable("Unexpected instr type to insert");
+  case WebAssembly::REF_TEST_FUNCREF_PSEUDO:
+    return LowerRefTestFuncRef(MI, DL, BB, TII);
   case WebAssembly::FP_TO_SINT_I32_F32:
     return LowerFPToInt(MI, DL, BB, TII, false, false, false,
                         WebAssembly::I32_TRUNC_S_F32);
@@ -2253,6 +2302,72 @@ SDValue WebAssemblyTargetLowering::LowerIntrinsic(SDValue Op,
                            DAG.getTargetExternalSymbol(TlsBase, PtrVT)),
         0);
   }
+  case Intrinsic::wasm_ref_test_func: {
+    // First emit the TABLE_GET instruction to convert function pointer ==>
+    // funcref
+    MachineFunction &MF = DAG.getMachineFunction();
+    auto PtrVT = getPointerTy(MF.getDataLayout());
+    MCSymbol *Table =
+        WebAssembly::getOrCreateFunctionTableSymbol(MF.getContext(), Subtarget);
+    SDValue TableSym = DAG.getMCSymbol(Table, PtrVT);
+    SDValue FuncRef =
+        SDValue(DAG.getMachineNode(WebAssembly::TABLE_GET_FUNCREF, DL,
+                                   MVT::funcref, TableSym, Op.getOperand(1)),
+                0);
+
+    SmallVector<SDValue, 4> Ops;
+    Ops.push_back(FuncRef);
+
+    // We want to encode the type information into an APInt which we'll put
+    // in a CImm. However, in SelectionDag/InstrEmitter.cpp there is no code
+    // path that emits a CImm. So we need a custom inserter to put it in.
+
+    // We'll put each type argument in a separate TargetConstant which gets
+    // lowered to a MachineInstruction Imm. We combine these into a CImm in our
+    // custom inserter because it creates a problem downstream to have all these
+    // extra immediates.
+    {
+      SDValue Operand = Op.getOperand(2);
+      MVT VT = Operand.getValueType().getSimpleVT();
+      WebAssembly::BlockType V;
+      if (VT == MVT::Untyped) {
+        V = WebAssembly::BlockType::Void;
+      } else if (VT == MVT::i32) {
+        V = WebAssembly::BlockType::I32;
+      } else if (VT == MVT::i64) {
+        V = WebAssembly::BlockType::I64;
+      } else if (VT == MVT::f32) {
+        V = WebAssembly::BlockType::F32;
+      } else if (VT == MVT::f64) {
+        V = WebAssembly::BlockType::F64;
+      } else {
+        llvm_unreachable("Unhandled type!");
+      }
+      Ops.push_back(DAG.getTargetConstant((int64_t)V, DL, MVT::i64));
+    }
+
+    for (unsigned i = 3; i < Op.getNumOperands(); ++i) {
+      SDValue Operand = Op.getOperand(i);
+      MVT VT = Operand.getValueType().getSimpleVT();
+      wasm::ValType V;
+      if (VT == MVT::i32) {
+        V = wasm::ValType::I32;
+      } else if (VT == MVT::i64) {
+        V = wasm::ValType::I64;
+      } else if (VT == MVT::f32) {
+        V = wasm::ValType::F32;
+      } else if (VT == MVT::f64) {
+        V = wasm::ValType::F64;
+      } else {
+        llvm_unreachable("Unhandled type!");
+      }
+      Ops.push_back(DAG.getTargetConstant((int64_t)V, DL, MVT::i64));
+    }
+
+    return SDValue(DAG.getMachineNode(WebAssembly::REF_TEST_FUNCREF_PSEUDO, DL,
+                                      MVT::i32, Ops),
+                   0);
+  }
   }
 }
 

llvm/lib/Target/WebAssembly/WebAssemblyInstrRef.td

@@ -36,6 +36,11 @@ multiclass REF_I<WebAssemblyRegClass rc, ValueType vt, string ht> {
         Requires<[HasReferenceTypes]>;
 }
 
+let usesCustomInserter = 1, isPseudo = 1 in defm REF_TEST_FUNCREF_PSEUDO
+    : I<(outs I32:$res), (ins TypeIndex:$type, FUNCREF:$ref, variable_ops),
+        (outs), (ins TypeIndex:$type), [], "ref.test.pseudo\t$type, $ref",
+        "ref.test.pseudo $type", -1>;
+
 defm REF_TEST_FUNCREF :
   I<(outs I32: $res),
     (ins TypeIndex:$type, FUNCREF: $ref),

llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp

@@ -15,13 +15,17 @@
 #include "WebAssemblyMCInstLower.h"
 #include "MCTargetDesc/WebAssemblyMCAsmInfo.h"
 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "MCTargetDesc/WebAssemblyMCTypeUtilities.h"
 #include "TargetInfo/WebAssemblyTargetInfo.h"
 #include "Utils/WebAssemblyTypeUtilities.h"
 #include "WebAssemblyAsmPrinter.h"
 #include "WebAssemblyMachineFunctionInfo.h"
 #include "WebAssemblyUtilities.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/BinaryFormat/Wasm.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
@@ -196,11 +200,80 @@ void WebAssemblyMCInstLower::lower(const MachineInstr *MI,
       MCOp = MCOperand::createReg(WAReg);
       break;
     }
+    case llvm::MachineOperand::MO_CImmediate: {
+      // Lower type index placeholder for ref.test
+      // Currently this is the only way that CImmediates show up so panic if we
+      // get confused.
+      unsigned DescIndex = I - NumVariadicDefs;
+      if (DescIndex >= Desc.NumOperands) {
+        llvm_unreachable("unexpected CImmediate operand");
+      }
+      const MCOperandInfo &Info = Desc.operands()[DescIndex];
+      if (Info.OperandType != WebAssembly::OPERAND_TYPEINDEX) {
+        llvm_unreachable("unexpected CImmediate operand");
+      }
+      auto CImm = MO.getCImm()->getValue();
+      auto NumWords = CImm.getNumWords();
+      // Extract the type data we packed into the CImm in LowerRefTestFuncRef.
+      // We need to load the words from most significant to least significant
+      // order because of the way we bitshifted them in from the right.
+      // The return type needs special handling because it could be void.
+      auto ReturnType = static_cast<WebAssembly::BlockType>(
+          CImm.extractBitsAsZExtValue(64, (NumWords - 1) * 64));
+      SmallVector<wasm::ValType, 2> Returns;
+      switch (ReturnType) {
+      case WebAssembly::BlockType::Invalid:
+        llvm_unreachable("Invalid return type");
+      case WebAssembly::BlockType::I32:
+        Returns = {wasm::ValType::I32};
+        break;
+      case WebAssembly::BlockType::I64:
+        Returns = {wasm::ValType::I64};
+        break;
+      case WebAssembly::BlockType::F32:
+        Returns = {wasm::ValType::F32};
+        break;
+      case WebAssembly::BlockType::F64:
+        Returns = {wasm::ValType::F64};
+        break;
+      case WebAssembly::BlockType::Void:
+        Returns = {};
+        break;
+      case WebAssembly::BlockType::Exnref:
+        Returns = {wasm::ValType::EXNREF};
+        break;
+      case WebAssembly::BlockType::Externref:
+        Returns = {wasm::ValType::EXTERNREF};
+        break;
+      case WebAssembly::BlockType::Funcref:
+        Returns = {wasm::ValType::FUNCREF};
+        break;
+      case WebAssembly::BlockType::V128:
+        Returns = {wasm::ValType::V128};
+        break;
+      case WebAssembly::BlockType::Multivalue: {
+        llvm_unreachable("Invalid return type");
+      }
+      }
+      SmallVector<wasm::ValType, 4> Params;
+
+      for (int I = NumWords - 2; I >= 0; I--) {
+        auto Val = CImm.extractBitsAsZExtValue(64, 64 * I);
+        auto ParamType = static_cast<wasm::ValType>(Val);
+        Params.push_back(ParamType);
+      }
+      MCOp = lowerTypeIndexOperand(std::move(Returns), std::move(Params));
+      break;
+    }
     case MachineOperand::MO_Immediate: {
       unsigned DescIndex = I - NumVariadicDefs;
       if (DescIndex < Desc.NumOperands) {
         const MCOperandInfo &Info = Desc.operands()[DescIndex];
+        // Replace type index placeholder with actual type index. The type index
+        // placeholders are Immediates and have an operand type of
+        // OPERAND_TYPEINDEX or OPERAND_SIGNATURE.
         if (Info.OperandType == WebAssembly::OPERAND_TYPEINDEX) {
+          // Lower type index placeholder for a CALL_INDIRECT instruction
           SmallVector<wasm::ValType, 4> Returns;
           SmallVector<wasm::ValType, 4> Params;
 
@@ -228,6 +301,7 @@ void WebAssemblyMCInstLower::lower(const MachineInstr *MI,
           break;
         }
         if (Info.OperandType == WebAssembly::OPERAND_SIGNATURE) {
+          // Lower type index placeholder for blocks
           auto BT = static_cast<WebAssembly::BlockType>(MO.getImm());
           assert(BT != WebAssembly::BlockType::Invalid);
           if (BT == WebAssembly::BlockType::Multivalue) {

llvm/test/CodeGen/WebAssembly/ref-test-func.ll

@@ -0,0 +1,42 @@
+; RUN: llc < %s -mcpu=mvp -mattr=+reference-types | FileCheck %s
+
+target triple = "wasm32-unknown-unknown"
+
+; CHECK-LABEL: test_function_pointer_signature_void:
+; CHECK-NEXT: .functype	test_function_pointer_signature_void (i32) -> ()
+; CHECK-NEXT: .local funcref
+; CHECK: local.get	0
+; CHECK-NEXT: table.get	__indirect_function_table
+; CHECK-NEXT: local.tee	1
+; CHECK-NEXT: ref.test (f32, f64, i32) -> (f32)
+; CHECK-NEXT: call	use
+; CHECK-NEXT: local.get	1
+; CHECK-NEXT: ref.test (f32, f64, i32) -> (i32)
+; CHECK-NEXT: call	use
+; CHECK-NEXT: local.get	1
+; CHECK-NEXT: ref.test (i32, i32, i32) -> (i32)
+; CHECK-NEXT: call	use
+; CHECK-NEXT: local.get	1
+; CHECK-NEXT: ref.test (i32, i32, i32) -> ()
+; CHECK-NEXT: call	use
+; CHECK-NEXT: local.get	1
+; CHECK-NEXT: ref.test () -> ()
+; CHECK-NEXT: call	use
+
+; Function Attrs: nounwind
+define void @test_function_pointer_signature_void(ptr noundef %func) local_unnamed_addr #0 {
+entry:
+  %0 = tail call i32 (ptr, ...) @llvm.wasm.ref.test.func(ptr %func, float 0.000000e+00, float 0.000000e+00, double 0.000000e+00, i32 0)
+  tail call void @use(i32 noundef %0) #3
+  %1 = tail call i32 (ptr, ...) @llvm.wasm.ref.test.func(ptr %func, i32 0, float 0.000000e+00, double 0.000000e+00, i32 0)
+  tail call void @use(i32 noundef %1) #3
+  %2 = tail call i32 (ptr, ...) @llvm.wasm.ref.test.func(ptr %func, i32 0, i32 0, i32 0, i32 0)
+  tail call void @use(i32 noundef %2) #3
+  %3 = tail call i32 (ptr, ...) @llvm.wasm.ref.test.func(ptr %func, token poison, i32 0, i32 0, i32 0)
+  tail call void @use(i32 noundef %3) #3
+  %4 = tail call i32 (ptr, ...) @llvm.wasm.ref.test.func(ptr %func, token poison)
+  tail call void @use(i32 noundef %4) #3
+  ret void
+}
+
+declare void @use(i32 noundef) local_unnamed_addr #1