[turbofan] Introduce lazy bailout, masked as a call.

src/compiler/linkage.h

 // 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.
 
 #ifndef V8_COMPILER_LINKAGE_H_
 #define V8_COMPILER_LINKAGE_H_
 
 #include "src/base/flags.h"
 #include "src/compiler/frame.h"
 #include "src/compiler/machine-type.h"
@@ skipping 92 matching lines @@
 };
 
 typedef Signature<LinkageLocation> LocationSignature;
 
 // Describes a call to various parts of the compiler. Every call has the notion
 // of a "target", which is the first input to the call.
 class CallDescriptor final : public ZoneObject {
  public:
   // Describes the kind of this call, which determines the target.
   enum Kind {
-    kCallCodeObject,      // target is a Code object
-    kCallJSFunction,      // target is a JSFunction object
-    kCallAddress,         // target is a machine pointer
+    kCallCodeObject,  // target is a Code object
+    kCallJSFunction,  // target is a JSFunction object
+    kCallAddress,     // target is a machine pointer
+    kLazyBailout      // the call is no-op, only used for lazy bailout
   };
 
   enum Flag {
     kNoFlags = 0u,
     kNeedsFrameState = 1u << 0,
     kPatchableCallSite = 1u << 1,
     kNeedsNopAfterCall = 1u << 2,
     kHasExceptionHandler = 1u << 3,
     kHasLocalCatchHandler = 1u << 4,
     kSupportsTailCalls = 1u << 5,
@@ skipping 138 matching lines @@
   explicit Linkage(CallDescriptor* incoming) : incoming_(incoming) {}
 
   static CallDescriptor* ComputeIncoming(Zone* zone, CompilationInfo* info);
 
   // The call descriptor for this compilation unit describes the locations
   // of incoming parameters and the outgoing return value(s).
   CallDescriptor* GetIncomingDescriptor() const { return incoming_; }
   static CallDescriptor* GetJSCallDescriptor(Zone* zone, bool is_osr,
                                              int parameter_count,
                                              CallDescriptor::Flags flags);
+
   static CallDescriptor* GetRuntimeCallDescriptor(
       Zone* zone, Runtime::FunctionId function, int parameter_count,
       Operator::Properties properties, bool needs_frame_state = true);
 
+  static CallDescriptor* GetLazyBailoutDescriptor(Zone* zone);
+
   static CallDescriptor* GetStubCallDescriptor(
       Isolate* isolate, Zone* zone, const CallInterfaceDescriptor& descriptor,
       int stack_parameter_count, CallDescriptor::Flags flags,
       Operator::Properties properties = Operator::kNoProperties,
       MachineType return_type = kMachAnyTagged);
 
   // Creates a call descriptor for simplified C calls that is appropriate
   // for the host platform. This simplified calling convention only supports
   // integers and pointers of one word size each, i.e. no floating point,
   // structs, pointers to members, etc.
@@ skipping 55 matching lines @@
   CallDescriptor* const incoming_;
 
   DISALLOW_COPY_AND_ASSIGN(Linkage);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_LINKAGE_H_