[vm] Bypass malloc for large Zone allocations to avoid jemalloc leaks.

Revert 9a07ad88f4.

Bug: https://github.com/flutter/flutter/issues/29007
Change-Id: I6a5f51f0c3a54d354ec5f8495677d46f94d8a1d3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/100568
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>

runtime/vm/isolate.cc

@@ -949,8 +949,7 @@ Isolate::Isolate(const Dart_IsolateFlags& api_flags)
       catch_entry_moves_cache_(),
       embedder_entry_points_(NULL),
       obfuscation_map_(NULL),
-      reverse_pc_lookup_cache_(nullptr),
-      irregexp_backtrack_stack_(nullptr) {
+      reverse_pc_lookup_cache_(nullptr) {
   FlagsCopyFrom(api_flags);
   SetErrorsFatal(true);
   set_compilation_allowed(true);
@@ -982,9 +981,6 @@ Isolate::~Isolate() {
   // RELEASE_ASSERT(reload_context_ == NULL);
 #endif  // !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
 
-  delete[] irregexp_backtrack_stack_;
-  irregexp_backtrack_stack_ = nullptr;
-
   delete reverse_pc_lookup_cache_;
   reverse_pc_lookup_cache_ = nullptr;
 

runtime/vm/isolate.h

@@ -734,18 +734,6 @@ class Isolate : public BaseIsolate {
     reverse_pc_lookup_cache_ = table;
   }
 
-  // This doesn't belong here, but to avoid triggering bugs in jemalloc we
-  // allocate the irregexpinterpreter's stack once per isolate instead of once
-  // per regexp execution.
-  // See https://github.com/flutter/flutter/issues/29007
-  static constexpr intptr_t kIrregexpBacktrackStackSize = 1 << 16;
-  intptr_t* irregexp_backtrack_stack() {
-    if (irregexp_backtrack_stack_ == nullptr) {
-      irregexp_backtrack_stack_ = new intptr_t[kIrregexpBacktrackStackSize];
-    }
-    return irregexp_backtrack_stack_;
-  }
-
   // Isolate-specific flag handling.
   static void FlagsInitialize(Dart_IsolateFlags* api_flags);
   void FlagsCopyTo(Dart_IsolateFlags* api_flags) const;
@@ -1058,8 +1046,6 @@ class Isolate : public BaseIsolate {
 
   ReversePcLookupCache* reverse_pc_lookup_cache_;
 
-  intptr_t* irregexp_backtrack_stack_;
-
   static Dart_IsolateCreateCallback create_callback_;
   static Dart_IsolateShutdownCallback shutdown_callback_;
   static Dart_IsolateCleanupCallback cleanup_callback_;

runtime/vm/regexp_assembler_bytecode.cc

@@ -494,7 +494,7 @@ static IrregexpInterpreter::IrregexpResult ExecRaw(const RegExp& regexp,
       TypedData::Handle(zone, regexp.bytecode(is_one_byte, sticky));
   ASSERT(!bytecode.IsNull());
   IrregexpInterpreter::IrregexpResult result =
-      IrregexpInterpreter::Match(bytecode, subject, raw_output, index);
+      IrregexpInterpreter::Match(bytecode, subject, raw_output, index, zone);
 
   if (result == IrregexpInterpreter::RE_SUCCESS) {
     // Copy capture results to the start of the registers array.

runtime/vm/regexp_interpreter.cc

@@ -127,8 +127,8 @@ static int32_t Load16Aligned(const uint8_t* pc) {
 // matching terminates.
 class BacktrackStack {
  public:
-  explicit BacktrackStack(Isolate* isolate) {
-    data_ = isolate->irregexp_backtrack_stack();
+  explicit BacktrackStack(Zone* zone) {
+    data_ = zone->Alloc<intptr_t>(kBacktrackStackSize);
   }
 
   intptr_t* data() const { return data_; }
@@ -136,8 +136,7 @@ class BacktrackStack {
   intptr_t max_size() const { return kBacktrackStackSize; }
 
  private:
-  static constexpr intptr_t kBacktrackStackSize =
-      Isolate::kIrregexpBacktrackStackSize;
+  static const intptr_t kBacktrackStackSize = 1 << 16;
 
   intptr_t* data_;
 
@@ -149,12 +148,13 @@ static IrregexpInterpreter::IrregexpResult RawMatch(const uint8_t* code_base,
                                                     const String& subject,
                                                     int32_t* registers,
                                                     intptr_t current,
-                                                    uint32_t current_char) {
+                                                    uint32_t current_char,
+                                                    Zone* zone) {
   const uint8_t* pc = code_base;
   // BacktrackStack ensures that the memory allocated for the backtracking stack
   // is returned to the system or cached if there is no stack being cached at
   // the moment.
-  BacktrackStack backtrack_stack(Isolate::Current());
+  BacktrackStack backtrack_stack(zone);
   intptr_t* backtrack_stack_base = backtrack_stack.data();
   intptr_t* backtrack_sp = backtrack_stack_base;
   intptr_t backtrack_stack_space = backtrack_stack.max_size();
@@ -627,7 +627,8 @@ IrregexpInterpreter::IrregexpResult IrregexpInterpreter::Match(
     const TypedData& bytecode,
     const String& subject,
     int32_t* registers,
-    intptr_t start_position) {
+    intptr_t start_position,
+    Zone* zone) {
   NoSafepointScope no_safepoint;
   const uint8_t* code_base = reinterpret_cast<uint8_t*>(bytecode.DataAddr(0));
 
@@ -638,10 +639,10 @@ IrregexpInterpreter::IrregexpResult IrregexpInterpreter::Match(
 
   if (subject.IsOneByteString() || subject.IsExternalOneByteString()) {
     return RawMatch<uint8_t>(code_base, subject, registers, start_position,
-                             previous_char);
+                             previous_char, zone);
   } else if (subject.IsTwoByteString() || subject.IsExternalTwoByteString()) {
     return RawMatch<uint16_t>(code_base, subject, registers, start_position,
-                              previous_char);
+                              previous_char, zone);
   } else {
     UNREACHABLE();
     return IrregexpInterpreter::RE_FAILURE;

runtime/vm/regexp_interpreter.h

@@ -20,7 +20,8 @@ class IrregexpInterpreter : public AllStatic {
   static IrregexpResult Match(const TypedData& bytecode,
                               const String& subject,
                               int32_t* captures,
-                              intptr_t start_position);
+                              intptr_t start_position,
+                              Zone* zone);
 };
 
 }  // namespace dart

runtime/vm/zone.cc

@@ -11,6 +11,7 @@
 #include "vm/handles_impl.h"
 #include "vm/heap/heap.h"
 #include "vm/os.h"
+#include "vm/virtual_memory.h"
 
 namespace dart {
 
@@ -21,25 +22,28 @@ class Zone::Segment {
  public:
   Segment* next() const { return next_; }
   intptr_t size() const { return size_; }
+  VirtualMemory* memory() const { return memory_; }
 
   uword start() { return address(sizeof(Segment)); }
   uword end() { return address(size_); }
 
   // Allocate or delete individual segments.
   static Segment* New(intptr_t size, Segment* next);
+  static Segment* NewLarge(intptr_t size, Segment* next);
   static void DeleteSegmentList(Segment* segment);
+  static void DeleteLargeSegmentList(Segment* segment);
   static void IncrementMemoryCapacity(uintptr_t size);
   static void DecrementMemoryCapacity(uintptr_t size);
 
  private:
   Segment* next_;
   intptr_t size_;
+  VirtualMemory* memory_;
+  void* alignment_;
 
   // Computes the address of the nth byte in this segment.
   uword address(int n) { return reinterpret_cast<uword>(this) + n; }
 
-  static void Delete(Segment* segment) { free(segment); }
-
   DISALLOW_IMPLICIT_CONSTRUCTORS(Segment);
 };
 
@@ -49,13 +53,36 @@ Zone::Segment* Zone::Segment::New(intptr_t size, Zone::Segment* next) {
   if (result == NULL) {
     OUT_OF_MEMORY();
   }
-  ASSERT(Utils::IsAligned(result->start(), Zone::kAlignment));
 #ifdef DEBUG
   // Zap the entire allocated segment (including the header).
   memset(result, kZapUninitializedByte, size);
 #endif
   result->next_ = next;
   result->size_ = size;
+  result->memory_ = nullptr;
+  result->alignment_ = nullptr;  // Avoid unused variable warnings.
+  IncrementMemoryCapacity(size);
+  return result;
+}
+
+Zone::Segment* Zone::Segment::NewLarge(intptr_t size, Zone::Segment* next) {
+  size = Utils::RoundUp(size, VirtualMemory::PageSize());
+  VirtualMemory* memory = VirtualMemory::Allocate(size, false, "dart-zone");
+  if (memory == NULL) {
+    OUT_OF_MEMORY();
+  }
+  Segment* result = reinterpret_cast<Segment*>(memory->start());
+#ifdef DEBUG
+  // Zap the entire allocated segment (including the header).
+  memset(result, kZapUninitializedByte, size);
+#endif
+  result->next_ = next;
+  result->size_ = size;
+  result->memory_ = memory;
+  result->alignment_ = nullptr;  // Avoid unused variable warnings.
+
+  LSAN_REGISTER_ROOT_REGION(result, sizeof(*result));
+
   IncrementMemoryCapacity(size);
   return result;
 }
@@ -69,7 +96,23 @@ void Zone::Segment::DeleteSegmentList(Segment* head) {
     // Zap the entire current segment (including the header).
     memset(current, kZapDeletedByte, current->size());
 #endif
-    Segment::Delete(current);
+    free(current);
+    current = next;
+  }
+}
+
+void Zone::Segment::DeleteLargeSegmentList(Segment* head) {
+  Segment* current = head;
+  while (current != NULL) {
+    DecrementMemoryCapacity(current->size());
+    Segment* next = current->next();
+    VirtualMemory* memory = current->memory();
+#ifdef DEBUG
+    // Zap the entire current segment (including the header).
+    memset(current, kZapDeletedByte, current->size());
+#endif
+    LSAN_UNREGISTER_ROOT_REGION(current, sizeof(*current));
+    delete memory;
     current = next;
   }
 }
@@ -129,7 +172,7 @@ void Zone::DeleteAll() {
     Segment::DeleteSegmentList(head_);
   }
   if (large_segments_ != NULL) {
-    Segment::DeleteSegmentList(large_segments_);
+    Segment::DeleteLargeSegmentList(large_segments_);
   }
 // Reset zone state.
 #ifdef DEBUG
@@ -214,9 +257,9 @@ uword Zone::AllocateLargeSegment(intptr_t size) {
   ASSERT(free_size < size);
 
   // Create a new large segment and chain it up.
-  ASSERT(Utils::IsAligned(sizeof(Segment), kAlignment));
-  size += sizeof(Segment);  // Account for book keeping fields in size.
-  large_segments_ = Segment::New(size, large_segments_);
+  // Account for book keeping fields in size.
+  size += Utils::RoundUp(sizeof(Segment), kAlignment);
+  large_segments_ = Segment::NewLarge(size, large_segments_);
 
   uword result = Utils::RoundUp(large_segments_->start(), kAlignment);
   return result;

runtime/vm/zone_test.cc

@@ -176,4 +176,66 @@ VM_UNIT_TEST_CASE(NativeScopeZoneAllocation) {
   EXPECT_EQ(0UL, ApiNativeScope::current_memory_usage());
 }
 
+#if !defined(PRODUCT)
+// Allow for pooling in the malloc implementation.
+static const int64_t kRssSlack = 20 * MB;
+#endif  // !defined(PRODUCT)
+
+// clang-format off
+static const size_t kSizes[] = {
+  64 * KB,
+  64 * KB + 2 * kWordSize,
+  64 * KB - 2 * kWordSize,
+  128 * KB,
+  128 * KB + 2 * kWordSize,
+  128 * KB - 2 * kWordSize,
+  256 * KB,
+  256 * KB + 2 * kWordSize,
+  256 * KB - 2 * kWordSize,
+  512 * KB,
+  512 * KB + 2 * kWordSize,
+  512 * KB - 2 * kWordSize,
+};
+// clang-format on
+
+TEST_CASE(StressMallocDirectly) {
+#if !defined(PRODUCT)
+  int64_t start_rss = Service::CurrentRSS();
+#endif  // !defined(PRODUCT)
+
+  void* allocations[ARRAY_SIZE(kSizes)];
+  for (size_t i = 0; i < ((3u * GB) / (512u * KB)); i++) {
+    for (size_t j = 0; j < ARRAY_SIZE(kSizes); j++) {
+      allocations[j] = malloc(kSizes[j]);
+    }
+    for (size_t j = 0; j < ARRAY_SIZE(kSizes); j++) {
+      free(allocations[j]);
+    }
+  }
+
+#if !defined(PRODUCT)
+  int64_t stop_rss = Service::CurrentRSS();
+  EXPECT_LT(stop_rss, start_rss + kRssSlack);
+#endif  // !defined(PRODUCT)
+}
+
+TEST_CASE(StressMallocThroughZones) {
+#if !defined(PRODUCT)
+  int64_t start_rss = Service::CurrentRSS();
+#endif  // !defined(PRODUCT)
+
+  for (size_t i = 0; i < ((3u * GB) / (512u * KB)); i++) {
+    StackZone stack_zone(Thread::Current());
+    Zone* zone = stack_zone.GetZone();
+    for (size_t j = 0; j < ARRAY_SIZE(kSizes); j++) {
+      zone->Alloc<uint8_t>(kSizes[j]);
+    }
+  }
+
+#if !defined(PRODUCT)
+  int64_t stop_rss = Service::CurrentRSS();
+  EXPECT_LT(stop_rss, start_rss + kRssSlack);
+#endif  // !defined(PRODUCT)
+}
+
 }  // namespace dart

tests/corelib_2/regexp/jemalloc_leak_backtracking_stack_test.dart

@@ -0,0 +1,24 @@
+// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Regression test for https://github.com/flutter/flutter/issues/29007
+
+String escape(String string) {
+  var regex = new RegExp("(\\?|\\\$|\\*|\\(|\\)|\\[)|\\+|\\.|\\\\");
+  return string.replaceAllMapped(
+      regex, (Match m) => "\\" + string.substring(m.start, m.end));
+}
+
+main() {
+  var text = """
+Yet but three? Come one more.
+Two of both kinds make up four.
+""";
+  var accumulate = 0;
+  for (var i = 0; i < 65536; i++) {
+    accumulate += escape(text).length;
+  }
+
+  print(accumulate);
+}