Migrate NoSafepointScope; add constrained concurrent allocation to unit test

runtime/vm/heap.cc

Index: runtime/vm/heap.cc
diff --git a/runtime/vm/heap.cc b/runtime/vm/heap.cc
index 06da6f1b769e653b405668e7bc2c97ef8f770160..a5900b68681655bd28ac06223aecf9a760458e3a 100644
--- a/runtime/vm/heap.cc
+++ b/runtime/vm/heap.cc
@@ -74,7 +74,9 @@ Heap::~Heap() {
 
 
 uword Heap::AllocateNew(intptr_t size) {
-  ASSERT(isolate()->no_safepoint_scope_depth() == 0);
+  ASSERT(Thread::Current()->no_safepoint_scope_depth() == 0);
+  // Currently, only the Dart thread may allocate in new space.
+  isolate()->AssertCurrentThreadIsMutator();
   uword addr = new_space_.TryAllocate(size);
   if (addr == 0) {
     CollectGarbage(kNew);
@@ -88,7 +90,13 @@ uword Heap::AllocateNew(intptr_t size) {
 
 
 uword Heap::AllocateOld(intptr_t size, HeapPage::PageType type) {
-  ASSERT(isolate()->no_safepoint_scope_depth() == 0);
+  ASSERT(Thread::Current()->no_safepoint_scope_depth() == 0);
+#if defined(DEBUG)
+  // Currently, allocation from non-Dart threads must not trigger GC.
+  if (GrowthControlState()) {
+    isolate()->AssertCurrentThreadIsMutator();
+  }
+#endif
   uword addr = old_space_.TryAllocate(size, type);
   if (addr != 0) {
     return addr;
@@ -149,7 +157,7 @@ uword Heap::AllocateOld(intptr_t size, HeapPage::PageType type) {
 
 
 uword Heap::AllocatePretenured(intptr_t size) {
-  ASSERT(isolate()->no_safepoint_scope_depth() == 0);
+  ASSERT(Thread::Current()->no_safepoint_scope_depth() == 0);
   uword addr = old_space_.TryAllocateDataBump(size, PageSpace::kControlGrowth);
   if (addr != 0) return addr;
   return AllocateOld(size, HeapPage::kData);
@@ -157,7 +165,7 @@ uword Heap::AllocatePretenured(intptr_t size) {
 
 
 void Heap::AllocateExternal(intptr_t size, Space space) {
-  ASSERT(isolate()->no_safepoint_scope_depth() == 0);
+  ASSERT(Thread::Current()->no_safepoint_scope_depth() == 0);
   if (space == kNew) {
     new_space_.AllocateExternal(size);
     if (new_space_.ExternalInWords() > (FLAG_new_gen_ext_limit * MBInWords)) {
@@ -759,13 +767,13 @@ void Heap::PrintStats() {
 
 
 #if defined(DEBUG)
-NoSafepointScope::NoSafepointScope() : StackResource(Isolate::Current()) {
-  isolate()->IncrementNoSafepointScopeDepth();
+NoSafepointScope::NoSafepointScope() : StackResource(Thread::Current()) {
+  thread()->IncrementNoSafepointScopeDepth();
 }
 
 
 NoSafepointScope::~NoSafepointScope() {
-  isolate()->DecrementNoSafepointScopeDepth();
+  thread()->DecrementNoSafepointScopeDepth();
 }
 #endif  // defined(DEBUG)