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

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 878e778da068c3563b1d06d7446c2411cf82fe28..31099d22aca27c9996806b2805f80858e26a1efc 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -171,8 +171,7 @@ class X64OperandGenerator final : public OperandGenerator {
 };
 
 namespace {
-
-ArchOpcode GetLoadOpcode(LoadRepresentation load_rep) {
+ArchOpcode GetLoadOpcode(LoadRepresentation load_rep, bool protect) {
   ArchOpcode opcode = kArchNop;
   switch (load_rep.representation()) {
     case MachineRepresentation::kFloat32:
@@ -189,7 +188,7 @@ ArchOpcode GetLoadOpcode(LoadRepresentation load_rep) {
       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.
@@ -211,7 +210,8 @@ 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];
@@ -226,7 +226,8 @@ 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];