[regexp] Port RegExpExecStub to CSA (mostly)

src/code-stub-assembler.h

 // 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.
 
 #ifndef V8_CODE_STUB_ASSEMBLER_H_
 #define V8_CODE_STUB_ASSEMBLER_H_
 
 #include <functional>
 
 #include "src/compiler/code-assembler.h"
@@ skipping 671 matching lines @@
                                InstanceType instance_type,
                                char const* method_name);
 
   // Type checks.
   // Check whether the map is for an object with special properties, such as a
   // JSProxy or an object with interceptors.
   Node* InstanceTypeEqual(Node* instance_type, int type);
   Node* IsSpecialReceiverMap(Node* map);
   Node* IsSpecialReceiverInstanceType(Node* instance_type);
   Node* IsStringInstanceType(Node* instance_type);
+  Node* IsOneByteStringInstanceType(Node* instance_type);
+  Node* IsSequentialStringInstanceType(Node* instance_type);
   Node* IsString(Node* object);
   Node* IsJSObject(Node* object);
   Node* IsJSGlobalProxy(Node* object);
   Node* IsJSReceiverInstanceType(Node* instance_type);
   Node* IsJSReceiver(Node* object);
   Node* IsJSReceiverMap(Node* map);
   Node* IsMap(Node* object);
   Node* IsCallableMap(Node* map);
   Node* IsDeprecatedMap(Node* map);
   Node* IsCallable(Node* object);
@@ skipping 24 matching lines @@
   // Return the single character string with only {code}.
   Node* StringFromCharCode(Node* code);
   // Return a new string object which holds a substring containing the range
   // [from,to[ of string.  |from| and |to| are expected to be tagged.
   Node* SubString(Node* context, Node* string, Node* from, Node* to);
 
   // Return a new string object produced by concatenating |first| with |second|.
   Node* StringAdd(Node* context, Node* first, Node* second,
                   AllocationFlags flags = kNone);
 
+  // Tries to unpack |string| into a pseudo-sequential string. For instance,
+  // In addition to the work done by TryDerefExternalString and
+  // MaybeDerefIndirectString, this method can also unpack sliced strings into
+  // a (string, offset) pair. The same GC restrictions on the returned string
+  // value apply as for TryDerefExternalString.
+  void TryUnpackString(Variable* var_string, Variable* var_offset,
+                       Variable* var_instance_type, Label* if_bailout);
+
   // Unpack the external string, returning a pointer that (offset-wise) looks
   // like a sequential string.
   // Note that this pointer is not tagged and does not point to a real
   // sequential string instance, and may only be used to access the string
   // data. The pointer is GC-safe as long as a reference to the container
   // ExternalString is live.
   // |string| must be an external string. Bailout for short external strings.
   Node* TryDerefExternalString(Node* const string, Node* const instance_type,
                                Label* if_bailout);
 
@@ skipping 666 matching lines @@
   }
 #else
 #define CSA_SLOW_ASSERT(csa, x) ((void)0)
 #endif
 
 DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_CODE_STUB_ASSEMBLER_H_