[regexp] Add slow exec stub to reduce code size

src/builtins/builtins-regexp-gen.cc

 // Copyright 2017 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/builtins/builtins-regexp-gen.h"
 
 #include "src/builtins/builtins-constructor.h"
 #include "src/builtins/builtins-utils-gen.h"
 #include "src/builtins/builtins.h"
 #include "src/code-factory.h"
@@ skipping 430 matching lines @@
     Node* const pending_exception =
         Load(MachineType::AnyTagged(), pending_exception_address);
 
     // If there is no pending exception, a
     // stack overflow (on the backtrack stack) was detected in RegExp code.
 
     Label stack_overflow(this), rethrow(this);
     Branch(IsTheHole(pending_exception), &stack_overflow, &rethrow);
 
     Bind(&stack_overflow);
-    TailCallRuntime(Runtime::kThrowStackOverflow, context);
+    CallRuntime(Runtime::kThrowStackOverflow, context);
+    Unreachable();
 
     Bind(&rethrow);
-    TailCallRuntime(Runtime::kRegExpExecReThrow, context);
+    CallRuntime(Runtime::kRegExpExecReThrow, context);
+    Unreachable();
   }
 
   Bind(&runtime);
   {
     Node* const result = CallRuntime(Runtime::kRegExpExec, context, regexp,
                                      string, last_index, match_info);
     var_result.Bind(result);
     Goto(&out);
   }
 
@@ skipping 254 matching lines @@
                                                        Label* if_isunmodified,
                                                        Label* if_ismodified) {
   Node* const native_context = LoadNativeContext(context);
   Node* const initial_regexp_result_map =
       LoadContextElement(native_context, Context::REGEXP_RESULT_MAP_INDEX);
 
   Branch(WordEqual(map, initial_regexp_result_map), if_isunmodified,
          if_ismodified);
 }
 
+// Slow path stub for RegExpPrototypeExec to decrease code size.
+TF_BUILTIN(RegExpPrototypeExecSlow, RegExpBuiltinsAssembler) {
+  typedef RegExpPrototypeExecSlowDescriptor Descriptor;
+
+  Node* const regexp = Parameter(Descriptor::kReceiver);
+  Node* const string = Parameter(Descriptor::kString);
+  Node* const context = Parameter(Descriptor::kContext);
+
+  Return(RegExpPrototypeExecBody(context, regexp, string, false));
+}
+
 // ES#sec-regexp.prototype.exec
 // RegExp.prototype.exec ( string )
 TF_BUILTIN(RegExpPrototypeExec, RegExpBuiltinsAssembler) {
   Node* const maybe_receiver = Parameter(0);
   Node* const maybe_string = Parameter(1);
   Node* const context = Parameter(4);
 
   // Ensure {maybe_receiver} is a JSRegExp.
   Node* const regexp_map = ThrowIfNotInstanceType(
       context, maybe_receiver, JS_REGEXP_TYPE, "RegExp.prototype.exec");
   Node* const receiver = maybe_receiver;
 
   // Convert {maybe_string} to a String.
   Node* const string = ToString(context, maybe_string);
 
   Label if_isfastpath(this), if_isslowpath(this);
   Branch(IsInitialRegExpMap(context, regexp_map), &if_isfastpath,
          &if_isslowpath);
 
   Bind(&if_isfastpath);
   {
     Node* const result =
         RegExpPrototypeExecBody(context, receiver, string, true);
     Return(result);
   }
 
   Bind(&if_isslowpath);
   {
-    Node* const result =
-        RegExpPrototypeExecBody(context, receiver, string, false);
+    Node* const result = CallBuiltin(Builtins::kRegExpPrototypeExecSlow,
+                                     context, receiver, string);
     Return(result);
   }
 }
 
 Node* RegExpBuiltinsAssembler::FlagsGetter(Node* const context,
                                            Node* const regexp,
                                            bool is_fastpath) {
   Isolate* isolate = this->isolate();
 
   Node* const int_zero = IntPtrConstant(0);
@@ skipping 554 matching lines @@
 
 // ES6 21.2.5.15.
 TF_BUILTIN(RegExpPrototypeUnicodeGetter, RegExpBuiltinsAssembler) {
   FlagGetter(JSRegExp::kUnicode, v8::Isolate::kRegExpPrototypeUnicodeGetter,
              "RegExp.prototype.unicode");
 }
 
 // ES#sec-regexpexec Runtime Semantics: RegExpExec ( R, S )
 Node* RegExpBuiltinsAssembler::RegExpExec(Node* context, Node* regexp,
                                           Node* string) {
-  Isolate* isolate = this->isolate();
-
-  Node* const null = NullConstant();
+  CSA_ASSERT(this, Word32BinaryNot(IsFastRegExpMap(context, LoadMap(regexp))));
 
   Variable var_result(this, MachineRepresentation::kTagged);
-  Label out(this), if_isfastpath(this), if_isslowpath(this);
+  Label out(this);
 
-  Node* const map = LoadMap(regexp);
-  BranchIfFastRegExp(context, map, &if_isfastpath, &if_isslowpath);
+  // Take the slow path of fetching the exec property, calling it, and
+  // verifying its return value.
 
-  Bind(&if_isfastpath);
+  // Get the exec property.
+  Node* const exec =
+      GetProperty(context, regexp, isolate()->factory()->exec_string());
+
+  // Is {exec} callable?
+  Label if_iscallable(this), if_isnotcallable(this);
+
+  GotoIf(TaggedIsSmi(exec), &if_isnotcallable);
+
+  Node* const exec_map = LoadMap(exec);
+  Branch(IsCallableMap(exec_map), &if_iscallable, &if_isnotcallable);
+
+  Bind(&if_iscallable);
   {
-    Node* const result = RegExpPrototypeExecBody(context, regexp, string, true);
+    Callable call_callable = CodeFactory::Call(isolate());
+    Node* const result = CallJS(call_callable, context, exec, regexp, string);
+
+    var_result.Bind(result);
+    GotoIf(WordEqual(result, NullConstant()), &out);
+
+    ThrowIfNotJSReceiver(context, result,
+                         MessageTemplate::kInvalidRegExpExecResult, "unused");
+
+    Goto(&out);
+  }
+
+  Bind(&if_isnotcallable);
+  {
+    ThrowIfNotInstanceType(context, regexp, JS_REGEXP_TYPE,
+                           "RegExp.prototype.exec");
+
+    Node* const result = CallBuiltin(Builtins::kRegExpPrototypeExecSlow,
+                                     context, regexp, string);
     var_result.Bind(result);
     Goto(&out);
   }
 
-  Bind(&if_isslowpath);
-  {
-    // Take the slow path of fetching the exec property, calling it, and
-    // verifying its return value.
-
-    // Get the exec property.
-    Node* const exec =
-        GetProperty(context, regexp, isolate->factory()->exec_string());
-
-    // Is {exec} callable?
-    Label if_iscallable(this), if_isnotcallable(this);
-
-    GotoIf(TaggedIsSmi(exec), &if_isnotcallable);
-
-    Node* const exec_map = LoadMap(exec);
-    Branch(IsCallableMap(exec_map), &if_iscallable, &if_isnotcallable);
-
-    Bind(&if_iscallable);
-    {
-      Callable call_callable = CodeFactory::Call(isolate);
-      Node* const result = CallJS(call_callable, context, exec, regexp, string);
-
-      var_result.Bind(result);
-      GotoIf(WordEqual(result, null), &out);
-
-      ThrowIfNotJSReceiver(context, result,
-                           MessageTemplate::kInvalidRegExpExecResult, "unused");
-
-      Goto(&out);
-    }
-
-    Bind(&if_isnotcallable);
-    {
-      ThrowIfNotInstanceType(context, regexp, JS_REGEXP_TYPE,
-                             "RegExp.prototype.exec");
-
-      Node* const result =
-          RegExpPrototypeExecBody(context, regexp, string, false);
-      var_result.Bind(result);
-      Goto(&out);
-    }
-  }
-
   Bind(&out);
   return var_result.value();
 }
 
 // ES#sec-regexp.prototype.test
 // RegExp.prototype.test ( S )
 TF_BUILTIN(RegExpPrototypeTest, RegExpBuiltinsAssembler) {
   Node* const maybe_receiver = Parameter(0);
   Node* const maybe_string = Parameter(1);
   Node* const context = Parameter(4);
@@ skipping 1266 matching lines @@
   Bind(&if_matched);
   {
     Node* result =
         ConstructNewResultFromMatchInfo(context, regexp, match_indices, string);
     Return(result);
   }
 }
 
 }  // namespace internal
 }  // namespace v8