[wasm] OOB traps: build protected instruction list during codegen

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

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <algorithm>
 
 #include "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
@@ skipping 161 matching lines @@
       return kMode_MR1;
     }
   }
 
   bool CanBeBetterLeftOperand(Node* node) const {
     return !selector()->IsLive(node);
   }
 };
 
 namespace {
-
-ArchOpcode GetLoadOpcode(LoadRepresentation load_rep) {
+ArchOpcode GetLoadOpcode(LoadRepresentation load_rep, bool protect) {
   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 = kX64Movl;
+      opcode = protect ? kX64TrapMovl : kX64Movl;
       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();
       break;
   }
   return opcode;
 }
 
 }  // namespace
 
 void InstructionSelector::VisitLoad(Node* node) {
   LoadRepresentation load_rep = LoadRepresentationOf(node->op());
   X64OperandGenerator g(this);
 
-  ArchOpcode opcode = GetLoadOpcode(load_rep);
+  const bool protect = false;
+  ArchOpcode opcode = GetLoadOpcode(load_rep, protect);
   InstructionOperand outputs[1];
   outputs[0] = g.DefineAsRegister(node);
   InstructionOperand inputs[3];
   size_t input_count = 0;
   AddressingMode mode =
       g.GetEffectiveAddressMemoryOperand(node, inputs, &input_count);
   InstructionCode code = opcode | AddressingModeField::encode(mode);
   Emit(code, 1, outputs, input_count, inputs);
 }
 
 void InstructionSelector::VisitProtectedLoad(Node* node) {
   LoadRepresentation load_rep = LoadRepresentationOf(node->op());
   X64OperandGenerator g(this);
 
-  ArchOpcode opcode = GetLoadOpcode(load_rep);
+  const bool protect = true;
+  ArchOpcode opcode = GetLoadOpcode(load_rep, protect);
   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));
@@ skipping 2137 matching lines @@
 // static
 MachineOperatorBuilder::AlignmentRequirements
 InstructionSelector::AlignmentRequirements() {
   return MachineOperatorBuilder::AlignmentRequirements::
       FullUnalignedAccessSupport();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8