BASELINE: Update Chromium to 70.0.3538.78

Change-Id: Ie634710bf039e26c1957f4ae45e101bd4c434ae7
Reviewed-by: Michael Brüning <michael.bruning@qt.io>

12 files changed, 335 insertions, 265 deletions

diff --git a/chromium/v8/src/debug/arm/OWNERS b/chromium/v8/src/debug/arm/OWNERS
deleted file mode 100644
index 906a5ce6418..00000000000
--- a/chromium/v8/src/debug/arm/OWNERS
+++ /dev/null
@@ -1 +0,0 @@
-rmcilroy@chromium.org
diff --git a/chromium/v8/src/debug/arm64/OWNERS b/chromium/v8/src/debug/arm64/OWNERS
deleted file mode 100644
index 906a5ce6418..00000000000
--- a/chromium/v8/src/debug/arm64/OWNERS
+++ /dev/null
@@ -1 +0,0 @@
-rmcilroy@chromium.org
diff --git a/chromium/v8/src/debug/debug-coverage.cc b/chromium/v8/src/debug/debug-coverage.cc
index 9e7195b1f3e..f8b716f7c91 100644
--- a/chromium/v8/src/debug/debug-coverage.cc
+++ b/chromium/v8/src/debug/debug-coverage.cc
@@ -72,8 +72,7 @@ void SortBlockData(std::vector<CoverageBlock>& v) {
   std::sort(v.begin(), v.end(), CompareCoverageBlock);
 }
 
-std::vector<CoverageBlock> GetSortedBlockData(Isolate* isolate,
-                                              SharedFunctionInfo* shared) {
+std::vector<CoverageBlock> GetSortedBlockData(SharedFunctionInfo* shared) {
   DCHECK(shared->HasCoverageInfo());
 
   CoverageInfo* coverage_info =
@@ -172,6 +171,12 @@ class CoverageBlockIterator final {
     return function_->blocks[read_index_ + 1];
   }
 
+  CoverageBlock& GetPreviousBlock() {
+    DCHECK(IsActive());
+    DCHECK_GT(read_index_, 0);
+    return function_->blocks[read_index_ - 1];
+  }
+
   CoverageBlock& GetParent() {
     DCHECK(IsActive());
     return nesting_stack_.back();
@@ -326,6 +331,30 @@ void MergeNestedRanges(CoverageFunction* function) {
   }
 }
 
+void FilterAliasedSingletons(CoverageFunction* function) {
+  CoverageBlockIterator iter(function);
+
+  iter.Next();  // Advance once since we reference the previous block later.
+
+  while (iter.Next()) {
+    CoverageBlock& previous_block = iter.GetPreviousBlock();
+    CoverageBlock& block = iter.GetBlock();
+
+    bool is_singleton = block.end == kNoSourcePosition;
+    bool aliases_start = block.start == previous_block.start;
+
+    if (is_singleton && aliases_start) {
+      // The previous block must have a full range since duplicate singletons
+      // have already been merged.
+      DCHECK_NE(previous_block.end, kNoSourcePosition);
+      // Likewise, the next block must have another start position since
+      // singletons are sorted to the end.
+      DCHECK_IMPLIES(iter.HasNext(), iter.GetNextBlock().start != block.start);
+      iter.DeleteBlock();
+    }
+  }
+}
+
 void FilterUncoveredRanges(CoverageFunction* function) {
   CoverageBlockIterator iter(function);
 
@@ -385,13 +414,12 @@ bool IsBinaryMode(debug::Coverage::Mode mode) {
   }
 }
 
-void CollectBlockCoverage(Isolate* isolate, CoverageFunction* function,
-                          SharedFunctionInfo* info,
+void CollectBlockCoverage(CoverageFunction* function, SharedFunctionInfo* info,
                           debug::Coverage::Mode mode) {
   DCHECK(IsBlockMode(mode));
 
   function->has_block_coverage = true;
-  function->blocks = GetSortedBlockData(isolate, info);
+  function->blocks = GetSortedBlockData(info);
 
   // If in binary mode, only report counts of 0/1.
   if (mode == debug::Coverage::kBlockBinary) ClampToBinary(function);
@@ -399,6 +427,15 @@ void CollectBlockCoverage(Isolate* isolate, CoverageFunction* function,
   // Remove duplicate singleton ranges, keeping the max count.
   MergeDuplicateSingletons(function);
 
+  // Remove singleton ranges with the same start position as a full range and
+  // throw away their counts.
+  // Singleton ranges are only intended to split existing full ranges and should
+  // never expand into a full range. Consider 'if (cond) { ... } else { ... }'
+  // as a problematic example; if the then-block produces a continuation
+  // singleton, it would incorrectly expand into the else range.
+  // For more context, see https://crbug.com/v8/8237.
+  FilterAliasedSingletons(function);
+
   // Rewrite all singletons (created e.g. by continuations and unconditional
   // control flow) to ranges.
   RewritePositionSingletonsToRanges(function);
@@ -544,7 +581,7 @@ std::unique_ptr<Coverage> Coverage::Collect(
       CoverageFunction function(start, end, count, name);
 
       if (IsBlockMode(collectionMode) && info->HasCoverageInfo()) {
-        CollectBlockCoverage(isolate, &function, info, collectionMode);
+        CollectBlockCoverage(&function, info, collectionMode);
       }
 
       // Only include a function range if itself or its parent function is
diff --git a/chromium/v8/src/debug/debug-evaluate.cc b/chromium/v8/src/debug/debug-evaluate.cc
index 0dd23037723..583b41f1b28 100644
--- a/chromium/v8/src/debug/debug-evaluate.cc
+++ b/chromium/v8/src/debug/debug-evaluate.cc
@@ -32,7 +32,8 @@ MaybeHandle<Object> DebugEvaluate::Global(Isolate* isolate,
   ScriptOriginOptions origin_options(false, true);
   MaybeHandle<SharedFunctionInfo> maybe_function_info =
       Compiler::GetSharedFunctionInfoForScript(
-          source, Compiler::ScriptDetails(isolate->factory()->empty_string()),
+          isolate, source,
+          Compiler::ScriptDetails(isolate->factory()->empty_string()),
           origin_options, nullptr, nullptr, ScriptCompiler::kNoCompileOptions,
           ScriptCompiler::kNoCacheNoReason, NOT_NATIVES_CODE);
 
@@ -254,111 +255,112 @@ namespace {
 
 bool IntrinsicHasNoSideEffect(Runtime::FunctionId id) {
 // Use macro to include both inlined and non-inlined version of an intrinsic.
-#define INTRINSIC_WHITELIST(V)           \
-  /* Conversions */                      \
-  V(NumberToStringSkipCache)             \
-  V(ToBigInt)                            \
-  V(ToInteger)                           \
-  V(ToLength)                            \
-  V(ToNumber)                            \
-  V(ToObject)                            \
-  V(ToString)                            \
-  /* Type checks */                      \
-  V(IsArray)                             \
-  V(IsDate)                              \
-  V(IsFunction)                          \
-  V(IsJSProxy)                           \
-  V(IsJSReceiver)                        \
-  V(IsJSWeakMap)                         \
-  V(IsJSWeakSet)                         \
-  V(IsRegExp)                            \
-  V(IsSmi)                               \
-  V(IsTypedArray)                        \
-  /* Loads */                            \
-  V(LoadLookupSlotForCall)               \
-  /* Arrays */                           \
-  V(ArraySpeciesConstructor)             \
-  V(EstimateNumberOfElements)            \
-  V(GetArrayKeys)                        \
-  V(HasComplexElements)                  \
-  V(HasFastPackedElements)               \
-  V(NewArray)                            \
-  V(NormalizeElements)                   \
-  V(PrepareElementsForSort)              \
-  V(TrySliceSimpleNonFastElements)       \
-  V(TypedArrayGetBuffer)                 \
-  /* Errors */                           \
-  V(NewTypeError)                        \
-  V(ReThrow)                             \
-  V(ThrowCalledNonCallable)              \
-  V(ThrowInvalidStringLength)            \
-  V(ThrowIteratorResultNotAnObject)      \
-  V(ThrowReferenceError)                 \
-  V(ThrowSymbolIteratorInvalid)          \
-  /* Strings */                          \
-  V(RegExpInternalReplace)               \
-  V(StringIncludes)                      \
-  V(StringIndexOf)                       \
-  V(StringReplaceOneCharWithString)      \
-  V(StringSubstring)                     \
-  V(StringToNumber)                      \
-  V(StringTrim)                          \
-  /* BigInts */                          \
-  V(BigIntEqualToBigInt)                 \
-  V(BigIntToBoolean)                     \
-  V(BigIntToNumber)                      \
-  /* Literals */                         \
-  V(CreateArrayLiteral)                  \
-  V(CreateObjectLiteral)                 \
-  V(CreateRegExpLiteral)                 \
-  /* Called from builtins */             \
-  V(AllocateInNewSpace)                  \
-  V(AllocateInTargetSpace)               \
-  V(AllocateSeqOneByteString)            \
-  V(AllocateSeqTwoByteString)            \
-  V(ArrayIncludes_Slow)                  \
-  V(ArrayIndexOf)                        \
-  V(ArrayIsArray)                        \
-  V(ClassOf)                             \
-  V(GenerateRandomNumbers)               \
-  V(GetFunctionName)                     \
-  V(GetOwnPropertyDescriptor)            \
-  V(GlobalPrint)                         \
-  V(HasProperty)                         \
-  V(ObjectCreate)                        \
-  V(ObjectEntries)                       \
-  V(ObjectEntriesSkipFastPath)           \
-  V(ObjectHasOwnProperty)                \
-  V(ObjectValues)                        \
-  V(ObjectValuesSkipFastPath)            \
-  V(ObjectGetOwnPropertyNames)           \
-  V(ObjectGetOwnPropertyNamesTryFast)    \
-  V(RegExpInitializeAndCompile)          \
-  V(StackGuard)                          \
-  V(StringAdd)                           \
-  V(StringCharCodeAt)                    \
-  V(StringEqual)                         \
-  V(StringIndexOfUnchecked)              \
-  V(StringParseFloat)                    \
-  V(StringParseInt)                      \
-  V(SymbolDescriptiveString)             \
-  V(ThrowRangeError)                     \
-  V(ThrowTypeError)                      \
-  V(ToName)                              \
-  V(TransitionElementsKind)              \
-  /* Misc. */                            \
-  V(Call)                                \
-  V(CompleteInobjectSlackTrackingForMap) \
-  V(HasInPrototypeChain)                 \
-  V(MaxSmi)                              \
-  V(NewObject)                           \
-  V(SmiLexicographicCompare)             \
-  V(StringMaxLength)                     \
-  V(StringToArray)                       \
-  /* Test */                             \
-  V(GetOptimizationStatus)               \
-  V(OptimizeFunctionOnNextCall)          \
-  V(OptimizeOsr)                         \
+#define INTRINSIC_WHITELIST(V)                \
+  /* Conversions */                           \
+  V(NumberToString)                           \
+  V(ToBigInt)                                 \
+  V(ToInteger)                                \
+  V(ToLength)                                 \
+  V(ToNumber)                                 \
+  V(ToObject)                                 \
+  V(ToString)                                 \
+  /* Type checks */                           \
+  V(IsArray)                                  \
+  V(IsDate)                                   \
+  V(IsFunction)                               \
+  V(IsJSProxy)                                \
+  V(IsJSReceiver)                             \
+  V(IsRegExp)                                 \
+  V(IsSmi)                                    \
+  V(IsTypedArray)                             \
+  /* Loads */                                 \
+  V(LoadLookupSlotForCall)                    \
+  V(GetProperty)                              \
+  /* Arrays */                                \
+  V(ArraySpeciesConstructor)                  \
+  V(EstimateNumberOfElements)                 \
+  V(GetArrayKeys)                             \
+  V(HasComplexElements)                       \
+  V(HasFastPackedElements)                    \
+  V(NewArray)                                 \
+  V(NormalizeElements)                        \
+  V(PrepareElementsForSort)                   \
+  V(TrySliceSimpleNonFastElements)            \
+  V(TypedArrayGetBuffer)                      \
+  /* Errors */                                \
+  V(NewTypeError)                             \
+  V(ReThrow)                                  \
+  V(ThrowCalledNonCallable)                   \
+  V(ThrowInvalidStringLength)                 \
+  V(ThrowIteratorResultNotAnObject)           \
+  V(ThrowReferenceError)                      \
+  V(ThrowSymbolIteratorInvalid)               \
+  /* Strings */                               \
+  V(RegExpInternalReplace)                    \
+  V(StringIncludes)                           \
+  V(StringIndexOf)                            \
+  V(StringReplaceOneCharWithString)           \
+  V(StringSubstring)                          \
+  V(StringToNumber)                           \
+  V(StringTrim)                               \
+  /* BigInts */                               \
+  V(BigIntEqualToBigInt)                      \
+  V(BigIntToBoolean)                          \
+  V(BigIntToNumber)                           \
+  /* Literals */                              \
+  V(CreateArrayLiteral)                       \
+  V(CreateArrayLiteralWithoutAllocationSite)  \
+  V(CreateObjectLiteral)                      \
+  V(CreateObjectLiteralWithoutAllocationSite) \
+  V(CreateRegExpLiteral)                      \
+  /* Called from builtins */                  \
+  V(AllocateInNewSpace)                       \
+  V(AllocateInTargetSpace)                    \
+  V(AllocateSeqOneByteString)                 \
+  V(AllocateSeqTwoByteString)                 \
+  V(ArrayIncludes_Slow)                       \
+  V(ArrayIndexOf)                             \
+  V(ArrayIsArray)                             \
+  V(ClassOf)                                  \
+  V(GenerateRandomNumbers)                    \
+  V(GetFunctionName)                          \
+  V(GetOwnPropertyDescriptor)                 \
+  V(GlobalPrint)                              \
+  V(HasProperty)                              \
+  V(ObjectCreate)                             \
+  V(ObjectEntries)                            \
+  V(ObjectEntriesSkipFastPath)                \
+  V(ObjectHasOwnProperty)                     \
+  V(ObjectValues)                             \
+  V(ObjectValuesSkipFastPath)                 \
+  V(ObjectGetOwnPropertyNames)                \
+  V(ObjectGetOwnPropertyNamesTryFast)         \
+  V(RegExpInitializeAndCompile)               \
+  V(StackGuard)                               \
+  V(StringAdd)                                \
+  V(StringCharCodeAt)                         \
+  V(StringEqual)                              \
+  V(StringIndexOfUnchecked)                   \
+  V(StringParseFloat)                         \
+  V(StringParseInt)                           \
+  V(SymbolDescriptiveString)                  \
+  V(ThrowRangeError)                          \
+  V(ThrowTypeError)                           \
+  V(ToName)                                   \
+  V(TransitionElementsKind)                   \
+  /* Misc. */                                 \
+  V(Call)                                     \
+  V(CompleteInobjectSlackTrackingForMap)      \
+  V(HasInPrototypeChain)                      \
+  V(MaxSmi)                                   \
+  V(NewObject)                                \
+  V(SmiLexicographicCompare)                  \
+  V(StringMaxLength)                          \
+  V(StringToArray)                            \
+  /* Test */                                  \
+  V(GetOptimizationStatus)                    \
+  V(OptimizeFunctionOnNextCall)               \
+  V(OptimizeOsr)                              \
   V(UnblockConcurrentRecompilation)
 
 #define CASE(Name)       \
@@ -553,12 +555,14 @@ DebugInfo::SideEffectState BuiltinGetSideEffectState(Builtins::Name id) {
     case Builtins::kArrayPrototypeValues:
     case Builtins::kArrayIncludes:
     case Builtins::kArrayPrototypeEntries:
+    case Builtins::kArrayPrototypeFill:
     case Builtins::kArrayPrototypeFind:
     case Builtins::kArrayPrototypeFindIndex:
     case Builtins::kArrayPrototypeFlat:
     case Builtins::kArrayPrototypeFlatMap:
     case Builtins::kArrayPrototypeKeys:
     case Builtins::kArrayPrototypeSlice:
+    case Builtins::kArrayPrototypeSort:
     case Builtins::kArrayForEach:
     case Builtins::kArrayEvery:
     case Builtins::kArraySome:
@@ -567,6 +571,9 @@ DebugInfo::SideEffectState BuiltinGetSideEffectState(Builtins::Name id) {
     case Builtins::kArrayMap:
     case Builtins::kArrayReduce:
     case Builtins::kArrayReduceRight:
+    // Trace builtins.
+    case Builtins::kIsTraceCategoryEnabled:
+    case Builtins::kTrace:
     // TypedArray builtins.
     case Builtins::kTypedArrayConstructor:
     case Builtins::kTypedArrayPrototypeBuffer:
@@ -810,6 +817,7 @@ DebugInfo::SideEffectState BuiltinGetSideEffectState(Builtins::Name id) {
     case Builtins::kArrayIteratorPrototypeNext:
     case Builtins::kArrayPrototypePop:
     case Builtins::kArrayPrototypePush:
+    case Builtins::kArrayPrototypeReverse:
     case Builtins::kArrayPrototypeShift:
     case Builtins::kArraySplice:
     case Builtins::kArrayUnshift:
@@ -987,12 +995,7 @@ void DebugEvaluate::ApplySideEffectChecks(
   for (interpreter::BytecodeArrayIterator it(bytecode_array); !it.done();
        it.Advance()) {
     interpreter::Bytecode bytecode = it.current_bytecode();
-    if (BytecodeRequiresRuntimeCheck(bytecode)) {
-      interpreter::Bytecode debugbreak =
-          interpreter::Bytecodes::GetDebugBreak(bytecode);
-      bytecode_array->set(it.current_offset(),
-                          interpreter::Bytecodes::ToByte(debugbreak));
-    }
+    if (BytecodeRequiresRuntimeCheck(bytecode)) it.ApplyDebugBreak();
   }
 }
 
diff --git a/chromium/v8/src/debug/debug-scope-iterator.cc b/chromium/v8/src/debug/debug-scope-iterator.cc
index dbade081cbb..e71c1c07b3c 100644
--- a/chromium/v8/src/debug/debug-scope-iterator.cc
+++ b/chromium/v8/src/debug/debug-scope-iterator.cc
@@ -4,11 +4,12 @@
 
 #include "src/debug/debug-scope-iterator.h"
 
-#include "src/api.h"
+#include "src/api-inl.h"
 #include "src/debug/debug.h"
 #include "src/debug/liveedit.h"
 #include "src/frames-inl.h"
 #include "src/isolate.h"
+#include "src/objects/js-generator-inl.h"
 #include "src/wasm/wasm-objects-inl.h"
 
 namespace v8 {
diff --git a/chromium/v8/src/debug/debug-scopes.cc b/chromium/v8/src/debug/debug-scopes.cc
index 8c6fae1d9fc..01cd017eb22 100644
--- a/chromium/v8/src/debug/debug-scopes.cc
+++ b/chromium/v8/src/debug/debug-scopes.cc
@@ -12,6 +12,7 @@
 #include "src/frames-inl.h"
 #include "src/globals.h"
 #include "src/isolate-inl.h"
+#include "src/objects/js-generator-inl.h"
 #include "src/objects/module.h"
 #include "src/parsing/parse-info.h"
 #include "src/parsing/parsing.h"
diff --git a/chromium/v8/src/debug/debug-stack-trace-iterator.cc b/chromium/v8/src/debug/debug-stack-trace-iterator.cc
index bf1e1b623b4..14d2850b69c 100644
--- a/chromium/v8/src/debug/debug-stack-trace-iterator.cc
+++ b/chromium/v8/src/debug/debug-stack-trace-iterator.cc
@@ -4,7 +4,7 @@
 
 #include "src/debug/debug-stack-trace-iterator.h"
 
-#include "src/api.h"
+#include "src/api-inl.h"
 #include "src/debug/debug-evaluate.h"
 #include "src/debug/debug-scope-iterator.h"
 #include "src/debug/debug.h"
@@ -173,8 +173,7 @@ v8::MaybeLocal<v8::Value> DebugStackTraceIterator::Evaluate(
     v8::Local<v8::String> source, bool throw_on_side_effect) {
   DCHECK(!Done());
   Handle<Object> value;
-  i::SafeForInterruptsScope safe_for_interrupt_scope(
-      isolate_, i::StackGuard::TERMINATE_EXECUTION);
+  i::SafeForInterruptsScope safe_for_interrupt_scope(isolate_);
   if (!DebugEvaluate::Local(isolate_, iterator_.frame()->id(),
                             inlined_frame_index_, Utils::OpenHandle(*source),
                             throw_on_side_effect)
diff --git a/chromium/v8/src/debug/debug.cc b/chromium/v8/src/debug/debug.cc
index 47de9523a50..3a3a48b699a 100644
--- a/chromium/v8/src/debug/debug.cc
+++ b/chromium/v8/src/debug/debug.cc
@@ -7,7 +7,7 @@
 #include <memory>
 #include <unordered_set>
 
-#include "src/api.h"
+#include "src/api-inl.h"
 #include "src/arguments.h"
 #include "src/assembler-inl.h"
 #include "src/base/platform/mutex.h"
@@ -30,6 +30,7 @@
 #include "src/log.h"
 #include "src/messages.h"
 #include "src/objects/debug-objects-inl.h"
+#include "src/objects/js-generator-inl.h"
 #include "src/objects/js-promise-inl.h"
 #include "src/snapshot/natives.h"
 #include "src/snapshot/snapshot.h"
@@ -278,15 +279,12 @@ void BreakIterator::SkipToPosition(int position) {
 void BreakIterator::SetDebugBreak() {
   DebugBreakType debug_break_type = GetDebugBreakType();
   if (debug_break_type == DEBUGGER_STATEMENT) return;
+  HandleScope scope(isolate());
   DCHECK(debug_break_type >= DEBUG_BREAK_SLOT);
-  BytecodeArray* bytecode_array = debug_info_->DebugBytecodeArray();
-  interpreter::Bytecode bytecode =
-      interpreter::Bytecodes::FromByte(bytecode_array->get(code_offset()));
-  if (interpreter::Bytecodes::IsDebugBreak(bytecode)) return;
-  interpreter::Bytecode debugbreak =
-      interpreter::Bytecodes::GetDebugBreak(bytecode);
-  bytecode_array->set(code_offset(),
-                      interpreter::Bytecodes::ToByte(debugbreak));
+  Handle<BytecodeArray> bytecode_array(debug_info_->DebugBytecodeArray(),
+                                       isolate());
+  interpreter::BytecodeArrayAccessor(bytecode_array, code_offset())
+      .ApplyDebugBreak();
 }
 
 void BreakIterator::ClearDebugBreak() {
@@ -322,6 +320,7 @@ BreakLocation BreakIterator::GetBreakLocation() {
                        generator_object_reg_index);
 }
 
+Isolate* BreakIterator::isolate() { return debug_info_->GetIsolate(); }
 
 void DebugFeatureTracker::Track(DebugFeatureTracker::Feature feature) {
   uint32_t mask = 1 << feature;
@@ -334,8 +333,6 @@ void DebugFeatureTracker::Track(DebugFeatureTracker::Feature feature) {
 
 // Threading support.
 void Debug::ThreadInit() {
-  thread_local_.break_count_ = 0;
-  thread_local_.break_id_ = 0;
   thread_local_.break_frame_id_ = StackFrame::NO_ID;
   thread_local_.last_step_action_ = StepNone;
   thread_local_.last_statement_position_ = kNoSourcePosition;
@@ -355,19 +352,31 @@ void Debug::ThreadInit() {
 
 
 char* Debug::ArchiveDebug(char* storage) {
-  // Simply reset state. Don't archive anything.
-  ThreadInit();
+  MemCopy(storage, reinterpret_cast<char*>(&thread_local_),
+          ArchiveSpacePerThread());
   return storage + ArchiveSpacePerThread();
 }
 
-
 char* Debug::RestoreDebug(char* storage) {
-  // Simply reset state. Don't restore anything.
-  ThreadInit();
+  MemCopy(reinterpret_cast<char*>(&thread_local_), storage,
+          ArchiveSpacePerThread());
+
+  // Enter the debugger.
+  DebugScope debug_scope(this);
+
+  // Clear any one-shot breakpoints that may have been set by the other
+  // thread, and reapply breakpoints for this thread.
+  ClearOneShot();
+
+  if (thread_local_.last_step_action_ != StepNone) {
+    // Reset the previous step action for this thread.
+    PrepareStep(thread_local_.last_step_action_);
+  }
+
   return storage + ArchiveSpacePerThread();
 }
 
-int Debug::ArchiveSpacePerThread() { return 0; }
+int Debug::ArchiveSpacePerThread() { return sizeof(ThreadLocal); }
 
 void Debug::Iterate(RootVisitor* v) {
   v->VisitRootPointer(Root::kDebug, nullptr, &thread_local_.return_value_);
@@ -1571,11 +1580,10 @@ void Debug::FreeDebugInfoListNode(DebugInfoListNode* prev,
     prev->set_next(node->next());
   }
 
-  // Pack function_identifier back into the
-  // SFI::function_identifier_or_debug_info field.
+  // Pack script back into the
+  // SFI::script_or_debug_info field.
   Handle<DebugInfo> debug_info(node->debug_info());
-  debug_info->shared()->set_function_identifier_or_debug_info(
-      debug_info->function_identifier());
+  debug_info->shared()->set_script_or_debug_info(debug_info->script());
 
   delete node;
 }
@@ -1620,12 +1628,12 @@ Handle<FixedArray> Debug::GetLoadedScripts() {
   isolate_->heap()->CollectAllGarbage(Heap::kFinalizeIncrementalMarkingMask,
                                       GarbageCollectionReason::kDebugger);
   Factory* factory = isolate_->factory();
-  if (!factory->script_list()->IsFixedArrayOfWeakCells()) {
+  if (!factory->script_list()->IsWeakArrayList()) {
     return factory->empty_fixed_array();
   }
-  Handle<FixedArrayOfWeakCells> array =
-      Handle<FixedArrayOfWeakCells>::cast(factory->script_list());
-  Handle<FixedArray> results = factory->NewFixedArray(array->Length());
+  Handle<WeakArrayList> array =
+      Handle<WeakArrayList>::cast(factory->script_list());
+  Handle<FixedArray> results = factory->NewFixedArray(array->length());
   int length = 0;
   {
     Script::Iterator iterator(isolate_);
@@ -1730,7 +1738,6 @@ void Debug::OnException(Handle<Object> exception, Handle<Object> promise) {
 
   DebugScope debug_scope(this);
   HandleScope scope(isolate_);
-  PostponeInterruptsScope postpone(isolate_);
   DisableBreak no_recursive_break(this);
 
   Handle<Context> native_context(isolate_->native_context());
@@ -1858,7 +1865,6 @@ void Debug::ProcessCompileEvent(bool has_compile_error, Handle<Script> script) {
   SuppressDebug while_processing(this);
   DebugScope debug_scope(this);
   HandleScope scope(isolate_);
-  PostponeInterruptsScope postpone(isolate_);
   DisableBreak no_recursive_break(this);
   AllowJavascriptExecution allow_script(isolate_);
   debug_delegate_->ScriptCompiled(ToApiHandle<debug::Script>(script),
@@ -1999,15 +2005,14 @@ void Debug::PrintBreakLocation() {
 
 DebugScope::DebugScope(Debug* debug)
     : debug_(debug),
-      prev_(debug->debugger_entry()),
-      no_termination_exceptons_(debug_->isolate_,
-                                StackGuard::TERMINATE_EXECUTION) {
+      prev_(reinterpret_cast<DebugScope*>(
+          base::Relaxed_Load(&debug->thread_local_.current_debug_scope_))),
+      no_interrupts_(debug_->isolate_) {
   // Link recursive debugger entry.
   base::Relaxed_Store(&debug_->thread_local_.current_debug_scope_,
                       reinterpret_cast<base::AtomicWord>(this));
 
-  // Store the previous break id, frame id and return value.
-  break_id_ = debug_->break_id();
+  // Store the previous frame id and return value.
   break_frame_id_ = debug_->break_frame_id();
 
   // Create the new break info. If there is no proper frames there is no break
@@ -2016,7 +2021,6 @@ DebugScope::DebugScope(Debug* debug)
   bool has_frames = !it.done();
   debug_->thread_local_.break_frame_id_ =
       has_frames ? it.frame()->id() : StackFrame::NO_ID;
-  debug_->SetNextBreakId();
 
   debug_->UpdateState();
 }
@@ -2029,7 +2033,6 @@ DebugScope::~DebugScope() {
 
   // Restore to the previous break state.
   debug_->thread_local_.break_frame_id_ = break_frame_id_;
-  debug_->thread_local_.break_id_ = break_id_;
 
   debug_->UpdateState();
 }
@@ -2121,6 +2124,8 @@ void Debug::ClearSideEffectChecks(Handle<DebugInfo> debug_info) {
   Handle<BytecodeArray> original(debug_info->OriginalBytecodeArray(), isolate_);
   for (interpreter::BytecodeArrayIterator it(debug_bytecode); !it.done();
        it.Advance()) {
+    // Restore from original. This may copy only the scaling prefix, which is
+    // correct, since we patch scaling prefixes to debug breaks if exists.
     debug_bytecode->set(it.current_offset(),
                         original->get(it.current_offset()));
   }
@@ -2173,6 +2178,10 @@ bool Debug::PerformSideEffectCheck(Handle<JSFunction> function,
   return false;
 }
 
+Handle<Object> Debug::return_value_handle() {
+  return handle(thread_local_.return_value_, isolate_);
+}
+
 bool Debug::PerformSideEffectCheckForCallback(Handle<Object> callback_info) {
   DCHECK_EQ(isolate_->debug_execution_mode(), DebugInfo::kSideEffects);
   if (!callback_info.is_null() && callback_info->IsCallHandlerInfo() &&
diff --git a/chromium/v8/src/debug/debug.h b/chromium/v8/src/debug/debug.h
index 31881fe1069..a6ad7bd4daa 100644
--- a/chromium/v8/src/debug/debug.h
+++ b/chromium/v8/src/debug/debug.h
@@ -8,7 +8,6 @@
 #include <vector>
 
 #include "src/allocation.h"
-#include "src/assembler.h"
 #include "src/base/atomicops.h"
 #include "src/base/hashmap.h"
 #include "src/base/platform/platform.h"
@@ -30,6 +29,7 @@ namespace internal {
 
 // Forward declarations.
 class DebugScope;
+class JSGeneratorObject;
 
 // Step actions. NOTE: These values are in macros.py as well.
 enum StepAction : int8_t {
@@ -152,7 +152,7 @@ class BreakIterator {
  private:
   int BreakIndexFromPosition(int position);
 
-  Isolate* isolate() { return debug_info_->GetIsolate(); }
+  Isolate* isolate();
 
   DebugBreakType GetDebugBreakType();
 
@@ -314,8 +314,9 @@ class Debug {
   static int ArchiveSpacePerThread();
   void FreeThreadResources() { }
   void Iterate(RootVisitor* v);
+  void InitThread(const ExecutionAccess& lock) { ThreadInit(); }
 
-  bool CheckExecutionState() { return is_active() && break_id() != 0; }
+  bool CheckExecutionState() { return is_active(); }
 
   void StartSideEffectCheckMode();
   void StopSideEffectCheckMode();
@@ -330,11 +331,6 @@ class Debug {
   bool PerformSideEffectCheckForObject(Handle<Object> object);
 
   // Flags and states.
-  DebugScope* debugger_entry() {
-    return reinterpret_cast<DebugScope*>(
-        base::Relaxed_Load(&thread_local_.current_debug_scope_));
-  }
-
   inline bool is_active() const { return is_active_; }
   inline bool in_debug_scope() const {
     return !!base::Relaxed_Load(&thread_local_.current_debug_scope_);
@@ -347,11 +343,8 @@ class Debug {
   bool break_points_active() const { return break_points_active_; }
 
   StackFrame::Id break_frame_id() { return thread_local_.break_frame_id_; }
-  int break_id() { return thread_local_.break_id_; }
 
-  Handle<Object> return_value_handle() {
-    return handle(thread_local_.return_value_, isolate_);
-  }
+  Handle<Object> return_value_handle();
   Object* return_value() { return thread_local_.return_value_; }
   void set_return_value(Object* value) { thread_local_.return_value_ = value; }
 
@@ -393,9 +386,6 @@ class Debug {
   void UpdateState();
   void UpdateHookOnFunctionCall();
   void Unload();
-  void SetNextBreakId() {
-    thread_local_.break_id_ = ++thread_local_.break_count_;
-  }
 
   // Return the number of virtual frames below debugger entry.
   int CurrentFrameCount();
@@ -503,12 +493,6 @@ class Debug {
     // Top debugger entry.
     base::AtomicWord current_debug_scope_;
 
-    // Counter for generating next break id.
-    int break_count_;
-
-    // Current break id.
-    int break_id_;
-
     // Frame id for the frame of the current break.
     StackFrame::Id break_frame_id_;
 
@@ -578,8 +562,7 @@ class DebugScope BASE_EMBEDDED {
   Debug* debug_;
   DebugScope* prev_;               // Previous scope if entered recursively.
   StackFrame::Id break_frame_id_;  // Previous break frame id.
-  int break_id_;                   // Previous break id.
-  PostponeInterruptsScope no_termination_exceptons_;
+  PostponeInterruptsScope no_interrupts_;
 };
 
 // This scope is used to handle return values in nested debug break points.
diff --git a/chromium/v8/src/debug/liveedit.cc b/chromium/v8/src/debug/liveedit.cc
index 7193d0abd1e..371d1d55754 100644
--- a/chromium/v8/src/debug/liveedit.cc
+++ b/chromium/v8/src/debug/liveedit.cc
@@ -4,7 +4,7 @@
 
 #include "src/debug/liveedit.h"
 
-#include "src/api.h"
+#include "src/api-inl.h"
 #include "src/ast/ast-traversal-visitor.h"
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
@@ -17,6 +17,7 @@
 #include "src/messages.h"
 #include "src/objects-inl.h"
 #include "src/objects/hash-table-inl.h"
+#include "src/objects/js-generator-inl.h"
 #include "src/parsing/parse-info.h"
 #include "src/parsing/parsing.h"
 #include "src/source-position-table.h"
@@ -542,9 +543,25 @@ struct SourcePositionEvent {
     if (a.position != b.position) return a.position < b.position;
     if (a.type != b.type) return a.type < b.type;
     if (a.type == LITERAL_STARTS && b.type == LITERAL_STARTS) {
-      return a.literal->end_position() < b.literal->end_position();
+      // If the literals start in the same position, we want the one with the
+      // furthest (i.e. largest) end position to be first.
+      if (a.literal->end_position() != b.literal->end_position()) {
+        return a.literal->end_position() > b.literal->end_position();
+      }
+      // If they also end in the same position, we want the first in order of
+      // literal ids to be first.
+      return a.literal->function_literal_id() <
+             b.literal->function_literal_id();
     } else if (a.type == LITERAL_ENDS && b.type == LITERAL_ENDS) {
-      return a.literal->start_position() > b.literal->start_position();
+      // If the literals end in the same position, we want the one with the
+      // nearest (i.e. largest) start position to be first.
+      if (a.literal->start_position() != b.literal->start_position()) {
+        return a.literal->start_position() > b.literal->start_position();
+      }
+      // If they also end in the same position, we want the last in order of
+      // literal ids to be first.
+      return a.literal->function_literal_id() >
+             b.literal->function_literal_id();
     } else {
       return a.pos_diff < b.pos_diff;
     }
@@ -658,20 +675,33 @@ using LiteralMap = std::unordered_map<FunctionLiteral*, FunctionLiteral*>;
 void MapLiterals(const FunctionLiteralChanges& changes,
                  const std::vector<FunctionLiteral*>& new_literals,
                  LiteralMap* unchanged, LiteralMap* changed) {
+  // Track the top-level script function separately as it can overlap fully with
+  // another function, e.g. the script "()=>42".
+  const std::pair<int, int> kTopLevelMarker = std::make_pair(-1, -1);
   std::map<std::pair<int, int>, FunctionLiteral*> position_to_new_literal;
   for (FunctionLiteral* literal : new_literals) {
     DCHECK(literal->start_position() != kNoSourcePosition);
     DCHECK(literal->end_position() != kNoSourcePosition);
-    position_to_new_literal[std::make_pair(literal->start_position(),
-                                           literal->end_position())] = literal;
+    std::pair<int, int> key =
+        literal->function_literal_id() == FunctionLiteral::kIdTypeTopLevel
+            ? kTopLevelMarker
+            : std::make_pair(literal->start_position(),
+                             literal->end_position());
+    // Make sure there are no duplicate keys.
+    DCHECK_EQ(position_to_new_literal.find(key), position_to_new_literal.end());
+    position_to_new_literal[key] = literal;
   }
   LiteralMap mappings;
   std::unordered_map<FunctionLiteral*, ChangeState> change_state;
   for (const auto& change_pair : changes) {
     FunctionLiteral* literal = change_pair.first;
     const FunctionLiteralChange& change = change_pair.second;
-    auto it = position_to_new_literal.find(
-        std::make_pair(change.new_start_position, change.new_end_position));
+    std::pair<int, int> key =
+        literal->function_literal_id() == FunctionLiteral::kIdTypeTopLevel
+            ? kTopLevelMarker
+            : std::make_pair(change.new_start_position,
+                             change.new_end_position);
+    auto it = position_to_new_literal.find(key);
     if (it == position_to_new_literal.end() ||
         HasChangedScope(literal, it->second)) {
       change_state[literal] = ChangeState::DAMAGED;
@@ -775,22 +805,22 @@ class FunctionDataMap : public ThreadVisitor {
  public:
   void AddInterestingLiteral(int script_id, FunctionLiteral* literal,
                              bool should_restart) {
-    map_.emplace(std::make_pair(script_id, literal->function_literal_id()),
+    map_.emplace(GetFuncId(script_id, literal),
                  FunctionData{literal, should_restart});
   }
 
-  bool Lookup(Isolate* isolate, SharedFunctionInfo* sfi, FunctionData** data) {
-    int function_literal_id = sfi->FunctionLiteralId(isolate);
-    if (!sfi->script()->IsScript() || function_literal_id == -1) {
+  bool Lookup(SharedFunctionInfo* sfi, FunctionData** data) {
+    int start_position = sfi->StartPosition();
+    if (!sfi->script()->IsScript() || start_position == -1) {
       return false;
     }
     Script* script = Script::cast(sfi->script());
-    return Lookup(script->id(), function_literal_id, data);
+    return Lookup(GetFuncId(script->id(), sfi), data);
   }
 
   bool Lookup(Handle<Script> script, FunctionLiteral* literal,
               FunctionData** data) {
-    return Lookup(script->id(), literal->function_literal_id(), data);
+    return Lookup(GetFuncId(script->id(), literal), data);
   }
 
   void Fill(Isolate* isolate, Address* restart_frame_fp) {
@@ -800,20 +830,20 @@ class FunctionDataMap : public ThreadVisitor {
         if (obj->IsSharedFunctionInfo()) {
           SharedFunctionInfo* sfi = SharedFunctionInfo::cast(obj);
           FunctionData* data = nullptr;
-          if (!Lookup(isolate, sfi, &data)) continue;
+          if (!Lookup(sfi, &data)) continue;
           data->shared = handle(sfi, isolate);
         } else if (obj->IsJSFunction()) {
           JSFunction* js_function = JSFunction::cast(obj);
           SharedFunctionInfo* sfi = js_function->shared();
           FunctionData* data = nullptr;
-          if (!Lookup(isolate, sfi, &data)) continue;
+          if (!Lookup(sfi, &data)) continue;
           data->js_functions.emplace_back(js_function, isolate);
         } else if (obj->IsJSGeneratorObject()) {
           JSGeneratorObject* gen = JSGeneratorObject::cast(obj);
           if (gen->is_closed()) continue;
           SharedFunctionInfo* sfi = gen->function()->shared();
           FunctionData* data = nullptr;
-          if (!Lookup(isolate, sfi, &data)) continue;
+          if (!Lookup(sfi, &data)) continue;
           data->running_generators.emplace_back(gen, isolate);
         }
       }
@@ -843,7 +873,7 @@ class FunctionDataMap : public ThreadVisitor {
           stack_position = FunctionData::BELOW_NON_DROPPABLE_FRAME;
         }
         FunctionData* data = nullptr;
-        if (!Lookup(isolate, *sfi, &data)) continue;
+        if (!Lookup(*sfi, &data)) continue;
         if (!data->should_restart) continue;
         data->stack_position = stack_position;
         *restart_frame_fp = frame->fp();
@@ -854,8 +884,36 @@ class FunctionDataMap : public ThreadVisitor {
   }
 
  private:
-  bool Lookup(int script_id, int function_literal_id, FunctionData** data) {
-    auto it = map_.find(std::make_pair(script_id, function_literal_id));
+  // Unique id for a function: script_id + start_position, where start_position
+  // is special cased to -1 for top-level so that it does not overlap with a
+  // function whose start position is 0.
+  using FuncId = std::pair<int, int>;
+
+  FuncId GetFuncId(int script_id, FunctionLiteral* literal) {
+    int start_position = literal->start_position();
+    if (literal->function_literal_id() == 0) {
+      // This is the top-level script function literal, so special case its
+      // start position
+      DCHECK_EQ(start_position, 0);
+      start_position = -1;
+    }
+    return FuncId(script_id, start_position);
+  }
+
+  FuncId GetFuncId(int script_id, SharedFunctionInfo* sfi) {
+    DCHECK_EQ(script_id, Script::cast(sfi->script())->id());
+    int start_position = sfi->StartPosition();
+    DCHECK_NE(start_position, -1);
+    if (sfi->is_toplevel()) {
+      // This is the top-level function, so special case its start position
+      DCHECK_EQ(start_position, 0);
+      start_position = -1;
+    }
+    return FuncId(script_id, start_position);
+  }
+
+  bool Lookup(FuncId id, FunctionData** data) {
+    auto it = map_.find(id);
     if (it == map_.end()) return false;
     *data = &it->second;
     return true;
@@ -867,14 +925,13 @@ class FunctionDataMap : public ThreadVisitor {
       it.frame()->GetFunctions(&sfis);
       for (auto& sfi : sfis) {
         FunctionData* data = nullptr;
-        if (!Lookup(isolate, *sfi, &data)) continue;
+        if (!Lookup(*sfi, &data)) continue;
         data->stack_position = FunctionData::ARCHIVED_THREAD;
       }
     }
   }
 
-  using UniqueLiteralId = std::pair<int, int>;  // script_id + literal_id
-  std::map<UniqueLiteralId, FunctionData> map_;
+  std::map<FuncId, FunctionData> map_;
 };
 
 bool CanPatchScript(const LiteralMap& changed, Handle<Script> script,
@@ -932,7 +989,7 @@ bool CanRestartFrame(Isolate* isolate, Address fp,
   JavaScriptFrame::cast(restart_frame)->GetFunctions(&sfis);
   for (auto& sfi : sfis) {
     FunctionData* data = nullptr;
-    if (!function_data_map.Lookup(isolate, *sfi, &data)) continue;
+    if (!function_data_map.Lookup(*sfi, &data)) continue;
     auto new_literal_it = changed.find(data->literal);
     if (new_literal_it == changed.end()) continue;
     if (new_literal_it->second->scope()->new_target_var()) {
@@ -944,9 +1001,8 @@ bool CanRestartFrame(Isolate* isolate, Address fp,
   return true;
 }
 
-void TranslateSourcePositionTable(Handle<BytecodeArray> code,
+void TranslateSourcePositionTable(Isolate* isolate, Handle<BytecodeArray> code,
                                   const std::vector<SourceChangeRange>& diffs) {
-  Isolate* isolate = code->GetIsolate();
   SourcePositionTableBuilder builder;
 
   Handle<ByteArray> source_position_table(code->SourcePositionTable(), isolate);
@@ -979,8 +1035,8 @@ void UpdatePositions(Isolate* isolate, Handle<SharedFunctionInfo> sfi,
   sfi->SetFunctionTokenPosition(new_function_token_position,
                                 new_start_position);
   if (sfi->HasBytecodeArray()) {
-    TranslateSourcePositionTable(handle(sfi->GetBytecodeArray(), isolate),
-                                 diffs);
+    TranslateSourcePositionTable(
+        isolate, handle(sfi->GetBytecodeArray(), isolate), diffs);
   }
 }
 }  // anonymous namespace
@@ -1042,6 +1098,7 @@ void LiveEdit::PatchScript(Isolate* isolate, Handle<Script> script,
     return;
   }
 
+  std::map<int, int> start_position_to_unchanged_id;
   for (const auto& mapping : unchanged) {
     FunctionData* data = nullptr;
     if (!function_data_map.Lookup(script, mapping.first, &data)) continue;
@@ -1057,10 +1114,6 @@ void LiveEdit::PatchScript(Isolate* isolate, Handle<Script> script,
     }
     UpdatePositions(isolate, sfi, diffs);
 
-    MaybeObject* weak_redundant_new_sfi =
-        new_script->shared_function_infos()->Get(
-            mapping.second->function_literal_id());
-
     sfi->set_script(*new_script);
     if (sfi->HasUncompiledData()) {
       sfi->uncompiled_data()->set_function_literal_id(
@@ -1071,26 +1124,10 @@ void LiveEdit::PatchScript(Isolate* isolate, Handle<Script> script,
     DCHECK_EQ(sfi->FunctionLiteralId(isolate),
               mapping.second->function_literal_id());
 
-    // Swap the now-redundant, newly compiled SFI into the old script, so that
-    // we can look up the old function_literal_id using the new SFI when
-    // processing changed functions.
-    HeapObject* redundant_new_sfi_obj;
-    if (weak_redundant_new_sfi->ToStrongOrWeakHeapObject(
-            &redundant_new_sfi_obj)) {
-      SharedFunctionInfo* redundant_new_sfi =
-          SharedFunctionInfo::cast(redundant_new_sfi_obj);
-
-      redundant_new_sfi->set_script(*script);
-      if (redundant_new_sfi->HasUncompiledData()) {
-        redundant_new_sfi->uncompiled_data()->set_function_literal_id(
-            mapping.first->function_literal_id());
-      }
-      script->shared_function_infos()->Set(
-          mapping.first->function_literal_id(),
-          HeapObjectReference::Weak(redundant_new_sfi));
-      DCHECK_EQ(redundant_new_sfi->FunctionLiteralId(isolate),
-                mapping.first->function_literal_id());
-    }
+    // Save the new start_position -> id mapping, so that we can recover it when
+    // iterating over changed functions' constant pools.
+    start_position_to_unchanged_id[mapping.second->start_position()] =
+        mapping.second->function_literal_id();
 
     if (sfi->HasUncompiledDataWithPreParsedScope()) {
       sfi->ClearPreParsedScopeData();
@@ -1107,8 +1144,8 @@ void LiveEdit::PatchScript(Isolate* isolate, Handle<Script> script,
     for (int i = 0; i < constants->length(); ++i) {
       if (!constants->get(i)->IsSharedFunctionInfo()) continue;
       FunctionData* data = nullptr;
-      if (!function_data_map.Lookup(
-              isolate, SharedFunctionInfo::cast(constants->get(i)), &data)) {
+      if (!function_data_map.Lookup(SharedFunctionInfo::cast(constants->get(i)),
+                                    &data)) {
         continue;
       }
       auto change_it = changed.find(data->literal);
@@ -1148,44 +1185,48 @@ void LiveEdit::PatchScript(Isolate* isolate, Handle<Script> script,
       if (!constants->get(i)->IsSharedFunctionInfo()) continue;
       SharedFunctionInfo* inner_sfi =
           SharedFunctionInfo::cast(constants->get(i));
-      if (inner_sfi->script() != *script) continue;
-
-      // If the inner SFI's script is the old script, then this is actually a
-      // redundant new_script SFI where the old script SFI was unchanged, so we
-      // swapped their scripts in the unchanged iteration. This means that we
-      // have to update this changed SFI's inner SFI constant to point at the
-      // old inner SFI, which has already been patched to be on the new script.
-      //
-      // So, we look up FunctionData using the current, newly compiled
-      // inner_sfi, but the resulting FunctionData will still be referring to
-      // the old, unchanged SFI.
-      FunctionData* data = nullptr;
-      if (!function_data_map.Lookup(isolate, inner_sfi, &data)) continue;
-      Handle<SharedFunctionInfo> old_unchanged_inner_sfi =
-          data->shared.ToHandleChecked();
+
+      // See if there is a mapping from this function's start position to a
+      // unchanged function's id.
+      auto unchanged_it =
+          start_position_to_unchanged_id.find(inner_sfi->StartPosition());
+      if (unchanged_it == start_position_to_unchanged_id.end()) continue;
+
+      // Grab that function id from the new script's SFI list, which should have
+      // already been updated in in the unchanged pass.
+      SharedFunctionInfo* old_unchanged_inner_sfi =
+          SharedFunctionInfo::cast(new_script->shared_function_infos()
+                                       ->Get(unchanged_it->second)
+                                       ->GetHeapObject());
       // Now some sanity checks. Make sure that this inner_sfi is not the
       // unchanged SFI yet...
-      DCHECK_NE(*old_unchanged_inner_sfi, inner_sfi);
-      // ... that the unchanged SFI has already been processed and patched to be
-      // on the new script ...
+      DCHECK_NE(old_unchanged_inner_sfi, inner_sfi);
+      // ... and that the unchanged SFI has already been processed and patched
+      // to be on the new script ...
       DCHECK_EQ(old_unchanged_inner_sfi->script(), *new_script);
-      // ... and that the id of the unchanged SFI matches the unchanged target
-      // literal's id.
-      DCHECK_EQ(old_unchanged_inner_sfi->FunctionLiteralId(isolate),
-                unchanged[data->literal]->function_literal_id());
-      constants->set(i, *old_unchanged_inner_sfi);
+
+      constants->set(i, old_unchanged_inner_sfi);
     }
   }
 #ifdef DEBUG
   {
-    // Check that all the functions in the new script are valid and that their
-    // function literals match what is expected.
+    // Check that all the functions in the new script are valid, that their
+    // function literals match what is expected, and that start positions are
+    // unique.
     DisallowHeapAllocation no_gc;
 
     SharedFunctionInfo::ScriptIterator it(isolate, *new_script);
+    std::set<int> start_positions;
     while (SharedFunctionInfo* sfi = it.Next()) {
       DCHECK_EQ(sfi->script(), *new_script);
       DCHECK_EQ(sfi->FunctionLiteralId(isolate), it.CurrentIndex());
+      // Don't check the start position of the top-level function, as it can
+      // overlap with a function in the script.
+      if (sfi->is_toplevel()) {
+        DCHECK_EQ(start_positions.find(sfi->StartPosition()),
+                  start_positions.end());
+        start_positions.insert(sfi->StartPosition());
+      }
 
       if (!sfi->HasBytecodeArray()) continue;
       // Check that all the functions in this function's constant pool are also
diff --git a/chromium/v8/src/debug/mips/OWNERS b/chromium/v8/src/debug/mips/OWNERS
index 4ce9d7f91da..8bbcab4c2d0 100644
--- a/chromium/v8/src/debug/mips/OWNERS
+++ b/chromium/v8/src/debug/mips/OWNERS
@@ -1,3 +1,2 @@
-ivica.bogosavljevic@mips.com
-Miran.Karic@mips.com
-sreten.kovacevic@mips.com
\ No newline at end of file
+ibogosavljevic@wavecomp.com
+skovacevic@wavecomp.com
\ No newline at end of file
diff --git a/chromium/v8/src/debug/mips64/OWNERS b/chromium/v8/src/debug/mips64/OWNERS
index 4ce9d7f91da..8bbcab4c2d0 100644
--- a/chromium/v8/src/debug/mips64/OWNERS
+++ b/chromium/v8/src/debug/mips64/OWNERS
@@ -1,3 +1,2 @@
-ivica.bogosavljevic@mips.com
-Miran.Karic@mips.com
-sreten.kovacevic@mips.com
\ No newline at end of file
+ibogosavljevic@wavecomp.com
+skovacevic@wavecomp.com
\ No newline at end of file