[wasm] Introduce the TrapIf and TrapUnless operators to generate trap code.

src/compiler/ppc/instruction-selector-ppc.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 "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/ppc/frames-ppc.h"
 
@@ skipping 1769 matching lines @@
       kNotEqual, DeoptimizeReasonOf(node->op()), node->InputAt(1));
   VisitWord32CompareZero(this, node, node->InputAt(0), &cont);
 }
 
 void InstructionSelector::VisitDeoptimizeUnless(Node* node) {
   FlagsContinuation cont = FlagsContinuation::ForDeoptimize(
       kEqual, DeoptimizeReasonOf(node->op()), node->InputAt(1));
   VisitWord32CompareZero(this, node, node->InputAt(0), &cont);
 }
 
+void InstructionSelector::VisitTrapIf(Node* node) { UNREACHABLE(); }
+
+void InstructionSelector::VisitTrapUnless(Node* node) { UNREACHABLE(); }
+
 void InstructionSelector::VisitSwitch(Node* node, const SwitchInfo& sw) {
   PPCOperandGenerator g(this);
   InstructionOperand value_operand = g.UseRegister(node->InputAt(0));
 
   // Emit either ArchTableSwitch or ArchLookupSwitch.
   size_t table_space_cost = 4 + sw.value_range;
   size_t table_time_cost = 3;
   size_t lookup_space_cost = 3 + 2 * sw.case_count;
   size_t lookup_time_cost = sw.case_count;
   if (sw.case_count > 0 &&
@@ skipping 298 matching lines @@
 // static
 MachineOperatorBuilder::AlignmentRequirements
 InstructionSelector::AlignmentRequirements() {
   return MachineOperatorBuilder::AlignmentRequirements::
       FullUnalignedAccessSupport();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8