Resubmit change 6302 after fixing the compiler warning on older GCC compiler versions:

vm/code_descriptors_test.cc

Index: vm/code_descriptors_test.cc
===================================================================
--- vm/code_descriptors_test.cc	(revision 6329)
+++ vm/code_descriptors_test.cc	(working copy)
@@ -11,6 +11,7 @@
 #include "vm/code_descriptors.h"
 #include "vm/code_generator.h"
 #include "vm/dart_entry.h"
+#include "vm/native_entry.h"
 #include "vm/unit_test.h"
 
 namespace dart {
@@ -89,16 +90,16 @@
     // Validate the first stack map entry.
     stack_map ^= stack_map_list.At(0);
     EXPECT(stack_map.IsObject(0));
-    EXPECT_EQ(0, stack_map.Minimum());
-    EXPECT_EQ(0, stack_map.Maximum());
+    EXPECT_EQ(0, stack_map.MinimumBitOffset());
+    EXPECT_EQ(0, stack_map.MaximumBitOffset());
 
     // Validate the second stack map entry.
     stack_map ^= stack_map_list.At(1);
     EXPECT(stack_map.IsObject(0));
     EXPECT(!stack_map.IsObject(1));
     EXPECT(stack_map.IsObject(2));
-    EXPECT_EQ(0, stack_map.Minimum());
-    EXPECT_EQ(2, stack_map.Maximum());
+    EXPECT_EQ(0, stack_map.MinimumBitOffset());
+    EXPECT_EQ(2, stack_map.MaximumBitOffset());
 
     // Validate the third stack map entry.
     stack_map ^= stack_map_list.At(2);
@@ -107,8 +108,8 @@
     for (intptr_t i = 2; i <= 5; i++) {
       EXPECT(stack_map.IsObject(i));
     }
-    EXPECT_EQ(0, stack_map.Minimum());
-    EXPECT_EQ(5, stack_map.Maximum());
+    EXPECT_EQ(0, stack_map.MinimumBitOffset());
+    EXPECT_EQ(5, stack_map.MaximumBitOffset());
 
     // Validate the fourth stack map entry.
     stack_map ^= stack_map_list.At(3);
@@ -121,8 +122,8 @@
       EXPECT(!stack_map.IsObject(i));
     }
     EXPECT(stack_map.IsObject(10));
-    EXPECT_EQ(0, stack_map.Minimum());
-    EXPECT_EQ(10, stack_map.Maximum());
+    EXPECT_EQ(0, stack_map.MinimumBitOffset());
+    EXPECT_EQ(10, stack_map.MaximumBitOffset());
     retval = true;
   } else {
     retval = false;
@@ -132,6 +133,86 @@
 }
 CODEGEN_TEST_RUN(StackmapCodegen, Smi::New(1))
 
+
+DEFINE_NATIVE_ENTRY(NativeFunc, 2) {
+  GET_NATIVE_ARGUMENT(Smi, i, arguments->At(0));
+  GET_NATIVE_ARGUMENT(Smi, k, arguments->At(1));
+  EXPECT_EQ(10, i.Value());
+  EXPECT_EQ(20, k.Value());
+  Isolate::Current()->heap()->CollectAllGarbage();
+}
+
+
+static Dart_NativeFunction native_resolver(Dart_Handle name,
+                                           int argument_count) {
+  return reinterpret_cast<Dart_NativeFunction>(&DN_NativeFunc);
+}
+
+
+TEST_CASE(StackmapGC) {
+  const char* kScriptChars =
+      "class A {"
+      "  static void func(var i, var k) native 'NativeFunc';"
+      "  static foo() {"
+      "    var i;"
+      "    var s1;"
+      "    var k;"
+      "    var s2;"
+      "    var s3;"
+      "    i = 10; s1 = 'abcd'; k = 20; s2 = 'B'; s3 = 'C';"
+      "    func(i, k);"
+      "    return i + k; }"
+      "  static int moo() {"
+      "    var i = A.foo();"
+      "    Expect.equals(30, i);"
+      "  }\n"
+      "}\n";
+  // First setup the script and compile the script.
+  TestCase::LoadTestScript(kScriptChars, native_resolver);
+  const String& name = String::Handle(String::New(TestCase::url()));
+  const Library& lib = Library::Handle(Library::LookupLibrary(name));
+  EXPECT(!lib.IsNull());
+  Class& cls = Class::Handle(
+      lib.LookupClass(String::Handle(String::NewSymbol("A"))));
+  EXPECT(!cls.IsNull());
+
+  // Now compile the two functions 'A.foo' and 'A.moo'
+  String& function_moo_name = String::Handle(String::New("moo"));
+  Function& function_moo =
+      Function::Handle(cls.LookupStaticFunction(function_moo_name));
+  EXPECT(CompilerTest::TestCompileFunction(function_moo));
+  EXPECT(function_moo.HasCode());
+
+  String& function_foo_name = String::Handle(String::New("foo"));
+  Function& function_foo =
+      Function::Handle(cls.LookupStaticFunction(function_foo_name));
+  EXPECT(CompilerTest::TestCompileFunction(function_foo));
+  EXPECT(function_foo.HasCode());
+
+  // Build and setup a stackmap for function 'A.foo' in order to test the
+  // traversal of stack maps when a GC happens.
+  StackmapBuilder* builder = new StackmapBuilder();
+  EXPECT(builder != NULL);
+  builder->SetSlotAsValue(0);  // var i.
+  builder->SetSlotAsObject(1);  // var s1.
+  builder->SetSlotAsValue(2);  // var k.
+  builder->SetSlotAsObject(3);  // var s2.
+  builder->SetSlotAsObject(4);  // var s3.
+  builder->AddEntry(0);  // Add a stack map entry at pc offset 0.
+  const Code& code = Code::Handle(function_foo.unoptimized_code());
+  const Array& stack_maps = Array::Handle(builder->FinalizeStackmaps(code));
+  code.set_stackmaps(stack_maps);
+
+  // Now invoke 'A.moo' and it will trigger a GC when the native function
+  // is called, this should then cause the stack map of function 'A.foo'
+  // to be traversed and the appropriate objects visited.
+  GrowableArray<const Object*> arguments;
+  const Array& kNoArgumentNames = Array::Handle();
+  Object& result = Object::Handle();
+  result = DartEntry::InvokeStatic(function_foo, arguments, kNoArgumentNames);
+  EXPECT(!result.IsError());
+}
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32 || defined(TARGET_ARCH_X64)