Revert of [regexp] Add stub for RegExpExec instead of inlining (patchset #1...

Revert of [regexp] Add stub for RegExpExec instead of inlining (patchset #1 id:1 of https://codereview.chromium.org/2677073004/ )

Reason for revert:
Doesn't fix perf regressions in crbug.com/688972 and introduces new ones for RegExp in crbug.com/689395.

Original issue's description:
> [regexp] Add stub for RegExpExec instead of inlining
>
> The code produced for RegExpExec is quite large, and we ended up completely
> inlining it several spots.  This CL moves RegExpPrototypeExecBody into two
> stubs (one each for fast and slow paths) and converts inlined uses into stub
> calls. This decreases the local x64 snapshot size by around 80K.
>
> BUG=chromium:688972
>
> Review-Url: https://codereview.chromium.org/2677073004
> Cr-Commit-Position: refs/heads/master@{#42965}
> Committed: https://chromium.googlesource.com/v8/v8/+/5ea144afe3fd98896fc097a3523de9ab0cb8cd61

TBR=yangguo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:688972

Review-Url: https://codereview.chromium.org/2679063003
Cr-Commit-Position: refs/heads/master@{#42985}

src/builtins/builtins-regexp.cc

@@ -340,33 +340,6 @@ Node* RegExpBuiltinsAssembler::RegExpPrototypeExecBodyWithoutResult(
   return var_result.value();
 }
 
-// Wrapper around RegExpPrototypeExecBody to reduce code duplication.
-TF_BUILTIN(RegExpExecInternalFast, RegExpBuiltinsAssembler) {
-  typedef RegExpExecInternalDescriptor Descriptor;
-
-  Node* const regexp = Parameter(Descriptor::kReceiver);
-  Node* const string = Parameter(Descriptor::kString);
-  Node* const context = Parameter(Descriptor::kContext);
-
-  CSA_ASSERT(this, HasInstanceType(regexp, JS_REGEXP_TYPE));
-  CSA_ASSERT(this, IsString(string));
-
-  Return(RegExpPrototypeExecBody(context, regexp, string, true));
-}
-
-// Wrapper around RegExpPrototypeExecBody to reduce code duplication.
-TF_BUILTIN(RegExpExecInternalSlow, RegExpBuiltinsAssembler) {
-  typedef RegExpExecInternalDescriptor Descriptor;
-
-  Node* const regexp = Parameter(Descriptor::kReceiver);
-  Node* const string = Parameter(Descriptor::kString);
-  Node* const context = Parameter(Descriptor::kContext);
-
-  CSA_ASSERT(this, IsString(string));
-
-  Return(RegExpPrototypeExecBody(context, regexp, string, false));
-}
-
 // ES#sec-regexp.prototype.exec
 // RegExp.prototype.exec ( string )
 Node* RegExpBuiltinsAssembler::RegExpPrototypeExecBody(Node* const context,
@@ -525,14 +498,16 @@ TF_BUILTIN(RegExpPrototypeExec, RegExpBuiltinsAssembler) {
 
   Bind(&if_isfastpath);
   {
-    Callable exec_callable = CodeFactory::RegExpExecInternal(isolate(), true);
-    Return(CallStub(exec_callable, context, receiver, string));
+    Node* const result =
+        RegExpPrototypeExecBody(context, receiver, string, true);
+    Return(result);
   }
 
   Bind(&if_isslowpath);
   {
-    Callable exec_callable = CodeFactory::RegExpExecInternal(isolate(), false);
-    Return(CallStub(exec_callable, context, receiver, string));
+    Node* const result =
+        RegExpPrototypeExecBody(context, receiver, string, false);
+    Return(result);
   }
 }
 
@@ -1249,8 +1224,7 @@ Node* RegExpBuiltinsAssembler::RegExpExec(Node* context, Node* regexp,
 
   Bind(&if_isfastpath);
   {
-    Callable exec_callable = CodeFactory::RegExpExecInternal(isolate, true);
-    Node* const result = CallStub(exec_callable, context, regexp, string);
+    Node* const result = RegExpPrototypeExecBody(context, regexp, string, true);
     var_result.Bind(result);
     Goto(&out);
   }
@@ -1292,8 +1266,8 @@ Node* RegExpBuiltinsAssembler::RegExpExec(Node* context, Node* regexp,
       ThrowIfNotInstanceType(context, regexp, JS_REGEXP_TYPE,
                              "RegExp.prototype.exec");
 
-      Callable exec_callable = CodeFactory::RegExpExecInternal(isolate, false);
-      Node* const result = CallStub(exec_callable, context, regexp, string);
+      Node* const result =
+          RegExpPrototypeExecBody(context, regexp, string, false);
       var_result.Bind(result);
       Goto(&out);
     }
@@ -1550,12 +1524,10 @@ void RegExpBuiltinsAssembler::RegExpPrototypeMatchBody(Node* const context,
 
   Bind(&if_isnotglobal);
   {
-    if (is_fastpath) {
-      Callable exec_callable = CodeFactory::RegExpExecInternal(isolate, true);
-      Return(CallStub(exec_callable, context, regexp, string));
-    } else {
-      Return(RegExpExec(context, regexp, string));
-    }
+    Node* const result =
+        is_fastpath ? RegExpPrototypeExecBody(context, regexp, string, true)
+                    : RegExpExec(context, regexp, string);
+    Return(result);
   }
 
   Bind(&if_isglobal);

src/builtins/builtins.h

@@ -675,9 +675,6 @@ class Isolate;
   CPP(ReflectSet)                                                              \
   CPP(ReflectSetPrototypeOf)                                                   \
                                                                                \
-  TFS(RegExpExecInternalFast, BUILTIN, kNoExtraICState, RegExpExecInternal)    \
-  TFS(RegExpExecInternalSlow, BUILTIN, kNoExtraICState, RegExpExecInternal)    \
-                                                                               \
   /* RegExp */                                                                 \
   CPP(RegExpCapture1Getter)                                                    \
   CPP(RegExpCapture2Getter)                                                    \

src/code-factory.cc

@@ -264,14 +264,6 @@ TFS_BUILTIN(StringGreaterThanOrEqual)
 
 #undef TFS_BUILTIN
 
-// static
-Callable CodeFactory::RegExpExecInternal(Isolate* isolate, bool is_fastpath) {
-  Handle<Code> code(is_fastpath
-                        ? isolate->builtins()->RegExpExecInternalFast()
-                        : isolate->builtins()->RegExpExecInternalSlow());
-  return Callable(code, RegExpExecInternalDescriptor(isolate));
-}
-
 // static
 Callable CodeFactory::StringAdd(Isolate* isolate, StringAddFlags flags,
                                 PretenureFlag pretenure_flag) {

src/code-factory.h

@@ -96,13 +96,8 @@ class V8_EXPORT_PRIVATE CodeFactory final {
                                       OrdinaryToPrimitiveHint hint);
   static Callable NumberToString(Isolate* isolate);
 
-  // Platform-dependent entry point into the generated irregexp matcher code.
   static Callable RegExpExec(Isolate* isolate);
 
-  // Implements part of the specced glue logic around RegExp.prototype.exec.
-  // Usually results in a call to CodeFactory::RegExpExec.
-  static Callable RegExpExecInternal(Isolate* isolate, bool is_fastpath);
-
   static Callable Add(Isolate* isolate);
   static Callable Subtract(Isolate* isolate);
   static Callable Multiply(Isolate* isolate);

src/interface-descriptors.h

@@ -52,7 +52,6 @@ class PlatformInterfaceDescriptor;
   V(ConstructStub)                        \
   V(ConstructTrampoline)                  \
   V(RegExpExec)                           \
-  V(RegExpExecInternal)                   \
   V(RegExpReplace)                        \
   V(RegExpSplit)                          \
   V(CopyFastSmiOrObjectElements)          \
@@ -658,13 +657,6 @@ class RegExpExecDescriptor : public CallInterfaceDescriptor {
                                      CallInterfaceDescriptor)
 };
 
-class RegExpExecInternalDescriptor : public CallInterfaceDescriptor {
- public:
-  DEFINE_PARAMETERS(kReceiver, kString)
-  DECLARE_DEFAULT_DESCRIPTOR(RegExpExecInternalDescriptor,
-                             CallInterfaceDescriptor, kParameterCount)
-};
-
 class RegExpReplaceDescriptor : public CallInterfaceDescriptor {
  public:
   DEFINE_PARAMETERS(kReceiver, kString, kReplaceValue)