Add dead CodeRegionTable for tracking overwritten Dart code

runtime/vm/service_test.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_debugger_api.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/globals.h"
 #include "vm/message_handler.h"
@@ skipping 677 matching lines @@
   Dart_Handle result = Dart_Invoke(h_lib, NewString("main"), 0, NULL);
   EXPECT_VALID(result);
   const Class& class_a = Class::Handle(GetClass(lib, "A"));
   EXPECT(!class_a.IsNull());
   const Function& function_c = Function::Handle(GetFunction(class_a, "c"));
   EXPECT(!function_c.IsNull());
   const Code& code_c = Code::Handle(function_c.CurrentCode());
   EXPECT(!code_c.IsNull());
   // Use the entry of the code object as it's reference.
   uword entry = code_c.EntryPoint();
+  int64_t compile_timestamp = code_c.compile_timestamp();
   EXPECT_GT(code_c.Size(), 16);
   uword last = entry + code_c.Size();
 
   // Build a mock message handler and wrap it in a dart port.
   ServiceTestMessageHandler handler;
   Dart_Port port_id = PortMap::CreatePort(&handler);
   Dart_Handle port =
       Api::NewHandle(isolate, DartLibraryCalls::NewSendPort(port_id));
   EXPECT_VALID(port);
   EXPECT_VALID(Dart_SetField(h_lib, NewString("port"), port));
 
   Instance& service_msg = Instance::Handle();
 
   // Request an invalid code object.
   service_msg = Eval(h_lib, "[port, ['code', '0'], [], []]");
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   EXPECT_STREQ(
-    "{\"type\":\"Error\",\"id\":\"\",\"message\":\"Could not find code at 0\","
+    "{\"type\":\"Error\",\"id\":\"\",\"message\":\"Malformed code id: 0\","
     "\"request\":{\"arguments\":[\"code\",\"0\"],"
     "\"option_keys\":[],\"option_values\":[]}}", handler.msg());
 
-  // The following four tests check that a code object can be found
-  // inside the range: [code.EntryPoint(), code.EntryPoint() + code.Size()).
-  // Request code object at code.EntryPoint()
-  // Expect this to succeed as it is inside [entry, entry + size).
-  service_msg = EvalF(h_lib, "[port, ['code', '%" Px "'], [], []]", entry);
+  // The following test checks that a code object can be found only
+  // at compile_timestamp()-code.EntryPoint().
+  service_msg = EvalF(h_lib, "[port, ['code', '%" Px64"-%" Px "'], [], []]",
+                      compile_timestamp,
+                      entry);
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   {
     // Only perform a partial match.
     const intptr_t kBufferSize = 512;
     char buffer[kBufferSize];
     OS::SNPrint(buffer, kBufferSize-1,
-                "{\"type\":\"Code\",\"id\":\"code\\/%" Px "\",", entry);
+                "{\"type\":\"Code\",\"id\":\"code\\/%" Px64 "-%" Px "\",",
+                compile_timestamp,
+                entry);
     EXPECT_SUBSTRING(buffer, handler.msg());
   }
 
-  // Request code object at code.EntryPoint() + 16.
-  // Expect this to succeed as it is inside [entry, entry + size).
+  // Request code object at compile_timestamp-code.EntryPoint() + 16
+  // Expect this to fail because the address is not the entry point.
   uintptr_t address = entry + 16;
-  service_msg = EvalF(h_lib, "[port, ['code', '%" Px "'], [], []]", address);
+  service_msg = EvalF(h_lib, "[port, ['code', '%" Px64"-%" Px "'], [], []]",
+                      compile_timestamp,
+                      address);
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   {
     // Only perform a partial match.
     const intptr_t kBufferSize = 512;
     char buffer[kBufferSize];
     OS::SNPrint(buffer, kBufferSize-1,
-                "{\"type\":\"Code\",\"id\":\"code\\/%" Px "\",", entry);
+                "Could not find code with id: %" Px64 "-%" Px "",
+                compile_timestamp,
+                address);
     EXPECT_SUBSTRING(buffer, handler.msg());
   }
 
-  // Request code object at code.EntryPoint() + code.Size() - 1.
-  // Expect this to succeed as it is inside [entry, entry + size).
-  address = last - 1;
-  service_msg = EvalF(h_lib, "[port, ['code', '%" Px "'], [], []]", address);
+  // Request code object at (compile_timestamp - 1)-code.EntryPoint()
+  // Expect this to fail because the timestamp is wrong.
+  address = entry;
+  service_msg = EvalF(h_lib, "[port, ['code', '%" Px64"-%" Px "'], [], []]",
+                      compile_timestamp - 1,
+                      address);
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   {
     // Only perform a partial match.
     const intptr_t kBufferSize = 512;
     char buffer[kBufferSize];
     OS::SNPrint(buffer, kBufferSize-1,
-                "{\"type\":\"Code\",\"id\":\"code\\/%" Px "\",", entry);
+                "Could not find code with id: %" Px64 "-%" Px "",
+                compile_timestamp - 1,
+                address);
     EXPECT_SUBSTRING(buffer, handler.msg());
   }
 
-  // Request code object at code.EntryPoint() + code.Size(). Expect this
-  // to fail as it's outside of [entry, entry + size).
+  // Request native code at address. Expect the null code object back.
   address = last;
-  service_msg = EvalF(h_lib, "[port, ['code', '%" Px "'], [], []]", address);
+  service_msg = EvalF(h_lib, "[port, ['code', 'native-%" Px "'], [], []]",
+                      address);
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
-  {
-    const intptr_t kBufferSize = 1024;
-    char buffer[kBufferSize];
-    OS::SNPrint(buffer, kBufferSize-1,
-        "{\"type\":\"Error\",\"id\":\"\","
-        "\"message\":\"Could not find code at %" Px "\","
-        "\"request\":{\"arguments\":[\"code\",\"%" Px "\"],"
-        "\"option_keys\":[],\"option_values\":[]}}", address, address);
-    EXPECT_STREQ(buffer, handler.msg());
-  }
+  EXPECT_STREQ("{\"type\":\"null\"}", handler.msg());
+
+  // Request malformed native code.
+  service_msg = EvalF(h_lib, "[port, ['code', 'native%" Px "'], [], []]",
+                      address);
+  Service::HandleIsolateMessage(isolate, service_msg);
+  handler.HandleNextMessage();
+  EXPECT_SUBSTRING("\"message\":\"Malformed code id:", handler.msg());
 }
 
 
 TEST_CASE(Service_Cpu) {
   const char* kScript =
       "var port;\n"  // Set to our mock port by C++.
       "\n"
       "main() {\n"
       "}";
 
@@ skipping 217 matching lines @@
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   EXPECT_STREQ("alpha", handler.msg());
   service_msg = Eval(lib, "[port, ['beta'], [], []]");
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   EXPECT_STREQ("beta", handler.msg());
 }
 
 }  // namespace dart