Fixed issue in MallocHooks where a MallocHookScope was accidentally removed during a merge, causing…

runtime/vm/malloc_hooks_test.cc

Index: runtime/vm/malloc_hooks_test.cc
diff --git a/runtime/vm/malloc_hooks_test.cc b/runtime/vm/malloc_hooks_test.cc
index 791e2694aa9deff839b4454d2137c52575820a64..af432f9dccec06e07acfb902d779051b52887695 100644
--- a/runtime/vm/malloc_hooks_test.cc
+++ b/runtime/vm/malloc_hooks_test.cc
@@ -4,13 +4,15 @@
 
 #include "platform/globals.h"
 
-#if defined(DART_USE_TCMALLOC) && !defined(PRODUCT)
+#if defined(DART_USE_TCMALLOC) && !defined(PRODUCT) &&                         \
+    !defined(TARGET_ARCH_DBC) && !defined(TARGET_OS_FUCHSIA)
 
 #include "platform/assert.h"
-#include "vm/class_finalizer.h"
 #include "vm/globals.h"
 #include "vm/malloc_hooks.h"
-#include "vm/symbols.h"
+#include "vm/os.h"
+#include "vm/profiler.h"
+#include "vm/profiler_service.h"
 #include "vm/unit_test.h"
 
 namespace dart {
@@ -64,7 +66,7 @@ UNIT_TEST_CASE(FreeUnseenMemoryMallocHookTest) {
   EXPECT_EQ(0L, MallocHooks::heap_allocated_memory_in_bytes());
 
   const intptr_t buffer_size = 10;
-  volatile char* buffer = new char[buffer_size];
+  char* buffer = new char[buffer_size];
   MallocHookTestBufferInitializer(buffer, buffer_size);
 
   EXPECT_EQ(1L, MallocHooks::allocation_count());
@@ -85,6 +87,103 @@ UNIT_TEST_CASE(FreeUnseenMemoryMallocHookTest) {
   FLAG_enable_malloc_hooks = enable_malloc_hooks_saved;
 }
 
+
+VM_UNIT_TEST_CASE(StackTraceMallocHookSimpleTest) {
+  bool stack_traces_enabled = MallocHooks::stack_trace_collection_enabled();
+  MallocHooks::set_stack_trace_collection_enabled(true);
+
+  MallocHooks::ResetStats();
+  ASSERT(MallocHooks::ProfilingEnabled());
+
+  char* var = static_cast<char*>(malloc(16 * sizeof(char)));
+  Sample* sample = MallocHooks::GetSample(var);
+  EXPECT(sample != NULL);
+
+  free(var);
+  sample = MallocHooks::GetSample(var);
+  EXPECT(sample == NULL);
+  MallocHooks::set_stack_trace_collection_enabled(stack_traces_enabled);
+}
+
+
+static char* DART_NOINLINE StackTraceLengthHelper(uintptr_t* end_address) {
+  char* var = static_cast<char*>(malloc(16 * sizeof(char)));
+  *end_address = OS::GetProgramCounter();
+  return var;
+}
+
+
+VM_UNIT_TEST_CASE(StackTraceMallocHookLengthTest) {
+  bool stack_traces_enabled = MallocHooks::stack_trace_collection_enabled();
+  MallocHooks::set_stack_trace_collection_enabled(true);
+
+  uintptr_t test_start_address =
+      reinterpret_cast<uintptr_t>(Dart_TestStackTraceMallocHookLengthTest);
+  uintptr_t helper_start_address =
+      reinterpret_cast<uintptr_t>(StackTraceLengthHelper);
+  uintptr_t helper_end_address = 0;
+
+  MallocHooks::ResetStats();
+  ASSERT(MallocHooks::ProfilingEnabled());
+
+  char* var = StackTraceLengthHelper(&helper_end_address);
+  Sample* sample = MallocHooks::GetSample(var);
+  EXPECT(sample != NULL);
+  uintptr_t test_end_address = OS::GetProgramCounter();
+
+  // Ensure that all stack frames are where we expect them to be in the sample.
+  // If they aren't, the kSkipCount constant in malloc_hooks.cc is likely
+  // incorrect.
+  uword address = sample->At(0);
+  bool first_result =
+      (helper_start_address <= address) && (helper_end_address >= address);
+  EXPECT(first_result);
+  address = sample->At(1);
+  bool second_result =
+      (test_start_address <= address) && (test_end_address >= address);
+  EXPECT(second_result);
+
+  if (!(first_result && second_result)) {
+    OS::PrintErr(
+        "If this test is failing, it's likely that the value set for"
+        "the number of frames to skip in malloc_hooks.cc is "
+        "incorrect for this configuration/platform. This value can be"
+        " found in malloc_hooks.cc in the AllocationInfo class, and "
+        "is stored in the kSkipCount constant.");
+  }
+
+  free(var);
+  MallocHooks::set_stack_trace_collection_enabled(stack_traces_enabled);
+}
+
+
+ISOLATE_UNIT_TEST_CASE(StackTraceMallocHookSimpleJSONTest) {
+  bool stack_traces_enabled = MallocHooks::stack_trace_collection_enabled();
+  MallocHooks::set_stack_trace_collection_enabled(true);
+  MallocHooks::ResetStats();
+  ASSERT(MallocHooks::ProfilingEnabled());
+  ClearProfileVisitor cpv(Isolate::Current());
+  Profiler::sample_buffer()->VisitSamples(&cpv);
+
+  char* var = static_cast<char*>(malloc(16 * sizeof(char)));
+  JSONStream js;
+  ProfilerService::PrintNativeAllocationJSON(&js, Profile::kNoTags, -1, -1);
+  const char* json = js.ToCString();
+
+  // Check that all the stack frames from the current down to main are actually
+  // present in the profile. This is just a simple sanity check to make sure
+  // that the ProfileTrie has a representation of the stack trace collected when
+  // var is allocated. More intense testing is already done in profiler_test.cc.
+  EXPECT_SUBSTRING("\"dart::Dart_TestStackTraceMallocHookSimpleJSONTest()\"",
+                   json);
+  EXPECT_SUBSTRING("\"dart::TestCase::Run()\"", json);
+  EXPECT_SUBSTRING("\"dart::TestCaseBase::RunTest()\"", json);
+  EXPECT_SUBSTRING("\"main\"", json);
+
+  free(var);
+  MallocHooks::set_stack_trace_collection_enabled(stack_traces_enabled);
+}
+
 };  // namespace dart
 
 #endif  // defined(DART_USE_TCMALLOC) && !defined(PRODUCT)