VM: Array bounds checks that don't deoptimize for precompiled code.

runtime/vm/code_generator.cc

Index: runtime/vm/code_generator.cc
diff --git a/runtime/vm/code_generator.cc b/runtime/vm/code_generator.cc
index 3082168307cae0439c17f58c3d0c774a39f692fc..4255d077dab0c1d61c45a3e1ddf5543d1e972d37 100644
--- a/runtime/vm/code_generator.cc
+++ b/runtime/vm/code_generator.cc
@@ -91,6 +91,34 @@ DEFINE_RUNTIME_ENTRY(TraceFunctionExit, 1) {
 }
 
 
+DEFINE_RUNTIME_ENTRY(RangeError, 2) {
+  const Instance& length = Instance::CheckedHandle(arguments.ArgAt(0));
+  const Instance& index = Instance::CheckedHandle(arguments.ArgAt(1));
+  if (!length.IsInteger()) {
+    // Throw: new ArgumentError.value(length, "length", "is not an integer");
+    const Array& args = Array::Handle(Array::New(3));
+    args.SetAt(0, length);
+    args.SetAt(1, Symbols::Length());
+    args.SetAt(2, String::Handle(String::New("is not an integer")));
+    Exceptions::ThrowByType(Exceptions::kArgumentValue, args);
+  }
+  if (!index.IsInteger()) {
+    // Throw: new ArgumentError.value(length, "length", "is not an integer");

[Vyacheslav Egorov (Google), 2016/07/14 09:35:59]

comment should say index.

[Florian Schneider, 2016/07/14 17:05:21]

Done.

+    const Array& args = Array::Handle(Array::New(3));
+    args.SetAt(0, index);
+    args.SetAt(1, Symbols::Index());
+    args.SetAt(2, String::Handle(String::New("is not an integer")));
+    Exceptions::ThrowByType(Exceptions::kArgumentValue, args);
+  }
+  // Throw: new RangeError.range(index, 0, length, "length");
+  const Array& args = Array::Handle(Array::New(4));
+  args.SetAt(0, index);
+  args.SetAt(1, Integer::Handle(Integer::New(0)));
+  args.SetAt(2, length);
+  args.SetAt(3, Symbols::Length());
+  Exceptions::ThrowByType(Exceptions::kRange, args);
+}
+

[Vyacheslav Egorov (Google), 2016/07/14 09:35:59]

+1 empty line

[Florian Schneider, 2016/07/14 17:05:21]

Done.

 // Allocation of a fixed length array of given element type.
 // This runtime entry is never called for allocating a List of a generic type,
 // because a prior run time call instantiates the element type if necessary.