[turbofan] Add DebugBreak machine operator and support

src/code-stub-assembler.cc

 // Copyright 2016 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/code-stub-assembler.h"
 #include "src/code-factory.h"
 
 namespace v8 {
 namespace internal {
 
 using compiler::Node;
 
 CodeStubAssembler::CodeStubAssembler(Isolate* isolate, Zone* zone,
                                      const CallInterfaceDescriptor& descriptor,
                                      Code::Flags flags, const char* name,
                                      size_t result_size)
     : compiler::CodeAssembler(isolate, zone, descriptor, flags, name,
                               result_size) {}
 
 CodeStubAssembler::CodeStubAssembler(Isolate* isolate, Zone* zone,
                                      int parameter_count, Code::Flags flags,
                                      const char* name)
     : compiler::CodeAssembler(isolate, zone, parameter_count, flags, name) {}
 
+void CodeStubAssembler::Assert(Node* condition) {
+#if defined(DEBUG)
+  Label ok(this);
+  Label not_ok(this);
+  Branch(condition, &ok, &not_ok);
+  Bind(&not_ok);
+  DebugBreak();
+  Goto(&ok);
+  Bind(&ok);
+#endif
+}
+
 Node* CodeStubAssembler::BooleanMapConstant() {
   return HeapConstant(isolate()->factory()->boolean_map());
 }
 
 Node* CodeStubAssembler::EmptyStringConstant() {
   return LoadRoot(Heap::kempty_stringRootIndex);
 }
 
 Node* CodeStubAssembler::HeapNumberMapConstant() {
   return HeapConstant(isolate()->factory()->heap_number_map());
@@ skipping 1512 matching lines @@
         CallRuntime(Runtime::kOrdinaryHasInstance, context, callable, object));
   }
   Goto(&return_result);
 
   Bind(&return_result);
   return var_result.value();
 }
 
 }  // namespace internal
 }  // namespace v8