Reland "No longer OOM on invalid string length."

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3345 matching lines @@
 
 class ReplacementStringBuilder {
  public:
   ReplacementStringBuilder(Heap* heap,
                            Handle<String> subject,
                            int estimated_part_count)
       : heap_(heap),
         array_builder_(heap->isolate(), estimated_part_count),
         subject_(subject),
         character_count_(0),
-        is_ascii_(subject->IsOneByteRepresentation()),
-        overflowed_(false) {
+        is_ascii_(subject->IsOneByteRepresentation()) {
     // Require a non-zero initial size. Ensures that doubling the size to
     // extend the array will work.
     ASSERT(estimated_part_count > 0);
   }
 
   static inline void AddSubjectSlice(FixedArrayBuilder* builder,
                                      int from,
                                      int to) {
     ASSERT(from >= 0);
     int length = to - from;
@@ skipping 27 matching lines @@
     ASSERT(length > 0);
     AddElement(*string);
     if (!string->IsOneByteRepresentation()) {
       is_ascii_ = false;
     }
     IncrementCharacterCount(length);
   }
 
 
   Handle<String> ToString() {
-    if (overflowed_) {
-      heap_->isolate()->ThrowInvalidStringLength();
-      return Handle<String>();
-    }
-
     if (array_builder_.length() == 0) {
       return heap_->isolate()->factory()->empty_string();
     }
 
     Handle<String> joined_string;
     if (is_ascii_) {
       Handle<SeqOneByteString> seq = NewRawOneByteString(character_count_);
+      RETURN_IF_EMPTY_HANDLE_VALUE(heap_->isolate(), seq, Handle<String>());
       DisallowHeapAllocation no_gc;
       uint8_t* char_buffer = seq->GetChars();
       StringBuilderConcatHelper(*subject_,
                                 char_buffer,
                                 *array_builder_.array(),
                                 array_builder_.length());
       joined_string = Handle<String>::cast(seq);
     } else {
       // Non-ASCII.
       Handle<SeqTwoByteString> seq = NewRawTwoByteString(character_count_);
+      RETURN_IF_EMPTY_HANDLE_VALUE(heap_->isolate(), seq, Handle<String>());
       DisallowHeapAllocation no_gc;
       uc16* char_buffer = seq->GetChars();
       StringBuilderConcatHelper(*subject_,
                                 char_buffer,
                                 *array_builder_.array(),
                                 array_builder_.length());
       joined_string = Handle<String>::cast(seq);
     }
     return joined_string;
   }
 
 
   void IncrementCharacterCount(int by) {
     if (character_count_ > String::kMaxLength - by) {
-      overflowed_ = true;
+      STATIC_ASSERT(String::kMaxLength < kMaxInt);
+      character_count_ = kMaxInt;
+    } else {
+      character_count_ += by;
     }
-    character_count_ += by;
   }
 
  private:
   Handle<SeqOneByteString> NewRawOneByteString(int length) {
     return heap_->isolate()->factory()->NewRawOneByteString(length);
   }
 
 
   Handle<SeqTwoByteString> NewRawTwoByteString(int length) {
     return heap_->isolate()->factory()->NewRawTwoByteString(length);
   }
 
 
   void AddElement(Object* element) {
     ASSERT(element->IsSmi() || element->IsString());
     ASSERT(array_builder_.capacity() > array_builder_.length());
     array_builder_.Add(element);
   }
 
   Heap* heap_;
   FixedArrayBuilder array_builder_;
   Handle<String> subject_;
   int character_count_;
   bool is_ascii_;
-  bool overflowed_;
 };
 
 
 class CompiledReplacement {
  public:
   explicit CompiledReplacement(Zone* zone)
       : parts_(1, zone), replacement_substrings_(0, zone), zone_(zone) {}
 
   // Return whether the replacement is simple.
   bool Compile(Handle<String> replacement,
@@ skipping 436 matching lines @@
 
   int matches = indices.length();
   if (matches == 0) return *subject;
 
   // Detect integer overflow.
   int64_t result_len_64 =
       (static_cast<int64_t>(replacement_len) -
        static_cast<int64_t>(pattern_len)) *
       static_cast<int64_t>(matches) +
       static_cast<int64_t>(subject_len);
-  if (result_len_64 > INT_MAX) {
-    v8::internal::Heap::FatalProcessOutOfMemory("invalid string length", true);
+  int result_len;
+  if (result_len_64 > static_cast<int64_t>(String::kMaxLength)) {
+    STATIC_ASSERT(String::kMaxLength < kMaxInt);
+    result_len = kMaxInt;  // Provoke exception.
+  } else {
+    result_len = static_cast<int>(result_len_64);
   }
-  int result_len = static_cast<int>(result_len_64);
 
   int subject_pos = 0;
   int result_pos = 0;
 
-  Handle<ResultSeqString> result;
+  Handle<String> result_seq;
   if (ResultSeqString::kHasAsciiEncoding) {
-    result = Handle<ResultSeqString>::cast(
-        isolate->factory()->NewRawOneByteString(result_len));
+    result_seq = isolate->factory()->NewRawOneByteString(result_len);
   } else {
-    result = Handle<ResultSeqString>::cast(
-        isolate->factory()->NewRawTwoByteString(result_len));
+    result_seq = isolate->factory()->NewRawTwoByteString(result_len);
   }
+  RETURN_IF_EMPTY_HANDLE(isolate, result_seq);
+  Handle<ResultSeqString> result = Handle<ResultSeqString>::cast(result_seq);
 
   for (int i = 0; i < matches; i++) {
     // Copy non-matched subject content.
     if (subject_pos < indices.at(i)) {
       String::WriteToFlat(*subject,
                           result->GetChars() + result_pos,
                           subject_pos,
                           indices.at(i));
       result_pos += indices.at(i) - subject_pos;
     }
@@ skipping 159 matching lines @@
   if (new_length == 0) return isolate->heap()->empty_string();
 
   Handle<ResultSeqString> answer;
   if (ResultSeqString::kHasAsciiEncoding) {
     answer = Handle<ResultSeqString>::cast(
         isolate->factory()->NewRawOneByteString(new_length));
   } else {
     answer = Handle<ResultSeqString>::cast(
         isolate->factory()->NewRawTwoByteString(new_length));
   }
+  ASSERT(!answer.is_null());
 
   int prev = 0;
   int position = 0;
 
   do {
     start = current_match[0];
     end = current_match[1];
     if (prev < start) {
       // Add substring subject[prev;start] to answer string.
       String::WriteToFlat(*subject, answer->GetChars() + position, prev, start);
@@ skipping 2437 matching lines @@
 
   // Simpler handling of ASCII strings.
   //
   // NOTE: This assumes that the upper/lower case of an ASCII
   // character is also ASCII.  This is currently the case, but it
   // might break in the future if we implement more context and locale
   // dependent upper/lower conversions.
   if (s->IsOneByteRepresentationUnderneath()) {
     Handle<SeqOneByteString> result =
         isolate->factory()->NewRawOneByteString(length);
-
+    ASSERT(!result.is_null());  // Same length as input.
     DisallowHeapAllocation no_gc;
     String::FlatContent flat_content = s->GetFlatContent();
     ASSERT(flat_content.IsFlat());
     bool has_changed_character = false;
     bool is_ascii = FastAsciiConvert<Converter>(
         reinterpret_cast<char*>(result->GetChars()),
         reinterpret_cast<const char*>(flat_content.ToOneByteVector().start()),
         length,
         &has_changed_character);
     // If not ASCII, we discard the result and take the 2 byte path.
     if (is_ascii)  return has_changed_character ? *result : *s;
   }
 
   Handle<SeqString> result;
   if (s->IsOneByteRepresentation()) {
     result = isolate->factory()->NewRawOneByteString(length);
   } else {
     result = isolate->factory()->NewRawTwoByteString(length);
   }
+  ASSERT(!result.is_null());  // Same length as input.
+
   MaybeObject* maybe = ConvertCaseHelper(isolate, *s, *result, length, mapping);
   Object* answer;
   if (!maybe->ToObject(&answer)) return maybe;
   if (answer->IsString()) return answer;
 
   ASSERT(answer->IsSmi());
   length = Smi::cast(answer)->value();
   if (s->IsOneByteRepresentation() && length > 0) {
     result = isolate->factory()->NewRawOneByteString(length);
   } else {
     if (length < 0) length = -length;
     result = isolate->factory()->NewRawTwoByteString(length);
   }
+  RETURN_IF_EMPTY_HANDLE(isolate, result);
   return ConvertCaseHelper(isolate, *s, *result, length, mapping);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StringToLowerCase) {
   return ConvertCase(
       args, isolate, isolate->runtime_state()->to_lower_mapping());
 }
 
 
@@ skipping 624 matching lines @@
   if (max_nof_separators < (array_length - 1)) {
     return isolate->ThrowInvalidStringLength();
   }
   int length = (array_length - 1) * separator_length;
   for (int i = 0; i < array_length; i++) {
     Object* element_obj = fixed_array->get(i);
     RUNTIME_ASSERT(element_obj->IsString());
     String* element = String::cast(element_obj);
     int increment = element->length();
     if (increment > String::kMaxLength - length) {
-      return isolate->ThrowInvalidStringLength();
+      STATIC_ASSERT(String::kMaxLength < kMaxInt);
+      length = kMaxInt;  // Provoke exception;
+      break;
     }
     length += increment;
   }
 
   Handle<SeqTwoByteString> answer =
       isolate->factory()->NewRawTwoByteString(length);
+  RETURN_IF_EMPTY_HANDLE(isolate, answer);
 
   DisallowHeapAllocation no_gc;
 
   uc16* sink = answer->GetChars();
 #ifdef DEBUG
   uc16* end = sink + length;
 #endif
 
   String* first = String::cast(fixed_array->get(0));
   String* seperator_raw = *separator;
@@ skipping 2224 matching lines @@
       "not_date_object", HandleVector<Object>(NULL, 0)));
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ThrowMessage) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_SMI_ARG_CHECKED(message_id, 0);
   const char* message = GetBailoutReason(
       static_cast<BailoutReason>(message_id));
-  Handle<Name> message_handle =
+  Handle<String> message_handle =
       isolate->factory()->NewStringFromAscii(CStrVector(message));
+  RETURN_IF_EMPTY_HANDLE(isolate, message_handle);
   return isolate->Throw(*message_handle);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_StackGuard) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
 
   // First check if this is a real stack overflow.
   if (isolate->stack_guard()->IsStackOverflow()) {
@@ skipping 5571 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal