[Interpreter] Add support for jumps using constants with wide operands.

test/cctest/compiler/test-run-bytecode-graph-builder.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <utility>
 
+#include "src/base/utils/random-number-generator.h"
 #include "src/compiler/pipeline.h"
 #include "src/execution.h"
 #include "src/handles.h"
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/interpreter/interpreter.h"
 #include "src/parsing/parser.h"
 #include "test/cctest/cctest.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 2082 matching lines @@
              snippets[i].code_snippet, kFunctionName);
 
     BytecodeGraphTester tester(isolate, zone, script.start());
     auto callable = tester.GetCallable<>();
     Handle<Object> return_value = callable().ToHandleChecked();
     CHECK(return_value->SameValue(*snippets[i].return_value()));
   }
 }
 
 
+TEST(JumpWithConstantsAndWideConstants) {
+  HandleAndZoneScope scope;
+  auto isolate = scope.main_isolate();
+  const int kStep = 19;
+  int start = isolate->random_number_generator()->NextInt(kStep);

[rmcilroy, 2016/01/05 13:46:10]

Do you really need this random number generator? I think all it would bring
would be potential flakeyness (assuming the tests don't have a fixed seed) or
would be fixed anyway (assuming the tests use a fixed seed).

[oth, 2016/01/05 18:31:59]

Done. The hope was the bots ran different seeds and this'd drive more coverage.
Considered capturing the seed here, but this would still make repro awkward.

+  for (int constants = start; constants < 256 + 3 * kStep; constants += kStep) {
+    std::stringstream os;
+    // Generate a string that consumes constant pool entries and
+    // spread out branch distances in script below.
+    for (int i = 0; i < constants; i++) {
+      os << "var x_ = 'x_" << i << "';\n";
+    }
+    std::string filler(os.str());
+    os.str("");

[rmcilroy, 2016/01/05 13:46:10]

Please use a different std::stringstream  rather than resetting the one above

[oth, 2016/01/05 18:31:59]

Done.

+    os << "function " << kFunctionName << "(a) {\n";
+    os << "  " << filler;
+    os << "  for (var i = a; i < 2; i++) {\n";
+    os << "  " << filler;
+    os << "    if (i == 0) { " << filler << "i = 10; continue; }\n";
+    os << "    else if (i == a) { " << filler << "i = 12; break; }\n";
+    os << "    else { " << filler << " }\n";
+    os << "  }\n";
+    os << "  return i;\n";
+    os << "}\n";
+    os << kFunctionName << "(0);\n";
+    std::string script(os.str());
+    auto factory = isolate->factory();
+    auto zone = scope.main_zone();
+    for (int a = 0; a < 3; a++) {
+      BytecodeGraphTester tester(isolate, zone, script.c_str());
+      auto callable = tester.GetCallable<Handle<Object>>();
+      Handle<Object> return_val =
+          callable(factory->NewNumberFromInt(a)).ToHandleChecked();
+      static const int results[] = {11, 12, 2};
+      CHECK_EQ(Handle<Smi>::cast(return_val)->value(), results[a]);
+    }
+  }
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8