WIP: wasm oob trap handling experiments

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index 04c4df307fba45730a88ced167b1af0f122494a8..792ef7df4cf85e1877f46ae1785c767e54ec8782 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -200,6 +200,53 @@ void InstructionSelector::VisitLoad(Node* node) {
   Emit(code, 1, outputs, input_count, inputs);
 }
 
+void InstructionSelector::VisitTrapableLoad(Node* node) {
+  LoadRepresentation load_rep = LoadRepresentationOf(node->op());
+  X64OperandGenerator g(this);
+
+  ArchOpcode opcode = kArchNop;
+  switch (load_rep.representation()) {
+    case MachineRepresentation::kFloat32:
+      opcode = kX64Movss;
+      break;
+    case MachineRepresentation::kFloat64:
+      opcode = kX64Movsd;
+      break;
+    case MachineRepresentation::kBit:  // Fall through.
+    case MachineRepresentation::kWord8:
+      opcode = load_rep.IsSigned() ? kX64Movsxbl : kX64Movzxbl;
+      break;
+    case MachineRepresentation::kWord16:
+      opcode = load_rep.IsSigned() ? kX64Movsxwl : kX64Movzxwl;
+      break;
+    case MachineRepresentation::kWord32:
+      opcode = kX64TrapMovl;
+      break;
+    case MachineRepresentation::kTaggedSigned:   // Fall through.
+    case MachineRepresentation::kTaggedPointer:  // Fall through.
+    case MachineRepresentation::kTagged:         // Fall through.
+    case MachineRepresentation::kWord64:
+      opcode = kX64Movq;
+      break;
+    case MachineRepresentation::kSimd128:  // Fall through.
+    case MachineRepresentation::kNone:
+      UNREACHABLE();
+      return;
+  }
+
+  InstructionOperand outputs[1];
+  outputs[0] = g.DefineAsRegister(node);
+  InstructionOperand inputs[4];
+  size_t input_count = 0;
+  AddressingMode mode =
+      g.GetEffectiveAddressMemoryOperand(node, inputs, &input_count);
+  // Add the context parameter as an input.
+  inputs[input_count++] = g.UseUniqueRegister(node->InputAt(2));
+  // Add the source position as an input
+  inputs[input_count++] = g.UseImmediate(node->InputAt(3));
+  InstructionCode code = opcode | AddressingModeField::encode(mode);
+  Emit(code, 1, outputs, input_count, inputs);
+}
 
 void InstructionSelector::VisitStore(Node* node) {
   X64OperandGenerator g(this);