[stubs] Remove {CodeStub::GetCopy} support.

This removes the ability to create a copy of a code-stub with a given
replacement pattern applied. It is in preparation of having the ability
to write-protect code objects.

R=ishell@chromium.org
BUG=v8:6409

Change-Id: Id7528b3bfc53ece73d8c58b0ac96c6e5702a9d45
Reviewed-on: https://chromium-review.googlesource.com/654605Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47914}

BUILD.gn

@@ -1573,7 +1573,6 @@ v8_source_set("v8_base") {
     "src/field-index.h",
     "src/field-type.cc",
     "src/field-type.h",
-    "src/find-and-replace-pattern.h",
     "src/fixed-dtoa.cc",
     "src/fixed-dtoa.h",
     "src/flag-definitions.h",

src/code-stubs.cc

@@ -109,14 +109,6 @@ Code::Flags CodeStub::GetCodeFlags() const {
   return Code::ComputeFlags(GetCodeKind(), GetExtraICState());
 }
 
-Handle<Code> CodeStub::GetCodeCopy(const FindAndReplacePattern& pattern) {
-  Handle<Code> ic = GetCode();
-  ic = isolate()->factory()->CopyCode(ic);
-  ic->FindAndReplace(pattern);
-  RecordCodeGeneration(ic);
-  return ic;
-}
-
 void CodeStub::DeleteStubFromCacheForTesting() {
   Heap* heap = isolate_->heap();
   Handle<UnseededNumberDictionary> dict(heap->code_stubs());

src/code-stubs.h

@@ -9,7 +9,6 @@
 #include "src/assembler.h"
 #include "src/codegen.h"
 #include "src/factory.h"
-#include "src/find-and-replace-pattern.h"
 #include "src/globals.h"
 #include "src/interface-descriptors.h"
 #include "src/macro-assembler.h"
@@ -143,9 +142,6 @@ class CodeStub : public ZoneObject {
   // Retrieve the code for the stub. Generate the code if needed.
   Handle<Code> GetCode();
 
-  // Retrieve the code for the stub, make and return a copy of the code.
-  Handle<Code> GetCodeCopy(const FindAndReplacePattern& pattern);
-
   static Major MajorKeyFromKey(uint32_t key) {
     return static_cast<Major>(MajorKeyBits::decode(key));
   }

src/find-and-replace-pattern.h

-// 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.
-
-#ifndef V8_FIND_AND_REPLACE_PATTERN_H_
-#define V8_FIND_AND_REPLACE_PATTERN_H_
-
-#include "src/handles.h"
-
-namespace v8 {
-namespace internal {
-
-class Map;
-class Object;
-
-class FindAndReplacePattern {
- public:
-  FindAndReplacePattern() : count_(0) {}
-  void Add(Handle<Map> map_to_find, Handle<HeapObject> obj_to_replace) {
-    DCHECK(count_ < kMaxCount);
-    find_[count_] = map_to_find;
-    replace_[count_] = obj_to_replace;
-    ++count_;
-  }
-
- private:
-  static const int kMaxCount = 4;
-  int count_;
-  Handle<Map> find_[kMaxCount];
-  Handle<HeapObject> replace_[kMaxCount];
-  friend class Code;
-};
-
-}  // namespace internal
-}  // namespace v8
-
-#endif  // V8_FIND_AND_REPLACE_PATTERN_H_

src/objects.cc

@@ -14032,58 +14032,6 @@ SafepointEntry Code::GetSafepointEntry(Address pc) {
 }
 
 
-Object* Code::FindNthObject(int n, Map* match_map) {
-  DCHECK(is_inline_cache_stub());
-  DisallowHeapAllocation no_allocation;
-  int mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
-  for (RelocIterator it(this, mask); !it.done(); it.next()) {
-    RelocInfo* info = it.rinfo();
-    Object* object = info->target_object();
-    if (object->IsWeakCell()) object = WeakCell::cast(object)->value();
-    if (object->IsHeapObject()) {
-      if (HeapObject::cast(object)->map() == match_map) {
-        if (--n == 0) return object;
-      }
-    }
-  }
-  return NULL;
-}
-
-
-AllocationSite* Code::FindFirstAllocationSite() {
-  Object* result = FindNthObject(1, GetHeap()->allocation_site_map());
-  return (result != NULL) ? AllocationSite::cast(result) : NULL;
-}
-
-
-Map* Code::FindFirstMap() {
-  Object* result = FindNthObject(1, GetHeap()->meta_map());
-  return (result != NULL) ? Map::cast(result) : NULL;
-}
-
-
-void Code::FindAndReplace(const FindAndReplacePattern& pattern) {
-  DCHECK(is_inline_cache_stub() || is_handler());
-  DisallowHeapAllocation no_allocation;
-  int mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
-  STATIC_ASSERT(FindAndReplacePattern::kMaxCount < 32);
-  int current_pattern = 0;
-  for (RelocIterator it(this, mask); !it.done(); it.next()) {
-    RelocInfo* info = it.rinfo();
-    HeapObject* object = info->target_object();
-    if (object->IsWeakCell()) {
-      object = HeapObject::cast(WeakCell::cast(object)->value());
-    }
-    Map* map = object->map();
-    if (map == *pattern.find_[current_pattern]) {
-      info->set_target_object(*pattern.replace_[current_pattern]);
-      if (++current_pattern == pattern.count_) return;
-    }
-  }
-  UNREACHABLE();
-}
-
-
 namespace {
 template <typename Code>
 void SetStackFrameCacheCommon(Handle<Code> code,

src/objects.h

@@ -924,7 +924,6 @@ class Cell;
 class ConsString;
 class ElementsAccessor;
 class EnumCache;
-class FindAndReplacePattern;
 class FixedArrayBase;
 class PropertyArray;
 class FunctionLiteral;
@@ -3850,23 +3849,6 @@ class Code: public HeapObject {
   // Get the safepoint entry for the given pc.
   SafepointEntry GetSafepointEntry(Address pc);
 
-  // Find an object in a stub with a specified map
-  Object* FindNthObject(int n, Map* match_map);
-
-  // Find the first allocation site in an IC stub.
-  AllocationSite* FindFirstAllocationSite();
-
-  // Find the first map in an IC stub.
-  Map* FindFirstMap();
-
-  // For each (map-to-find, object-to-replace) pair in the pattern, this
-  // function replaces the corresponding placeholder in the code with the
-  // object-to-replace. The function assumes that pairs in the pattern come in
-  // the same order as the placeholders in the code.
-  // If the placeholder is a weak cell, then the value of weak cell is matched
-  // against the map-to-find.
-  void FindAndReplace(const FindAndReplacePattern& pattern);
-
   // The entire code object including its header is copied verbatim to the
   // snapshot so that it can be written in one, fast, memcpy during
   // deserialization. The deserializer will overwrite some pointers, rather

src/v8.gyp

@@ -970,7 +970,6 @@
         'field-index-inl.h',
         'field-type.cc',
         'field-type.h',
-        'find-and-replace-pattern.h',
         'fixed-dtoa.cc',
         'fixed-dtoa.h',
         'flag-definitions.h',