Add a new imgdiag tool to diff boot.art/core.art against a process

Analyze the dirty memory pages of a running process per-object,
this allows is to to fine-tune the dirty object binning algorithm in
image writer.

Also:
* Factor out oatdump command line parsing code into cmdline.h
* Factor out common build rules for building variations of binaries
* Add a gtest for imgdiag

Bug: 17611661
Change-Id: I3ac852a0d223af66f6d59ae5dbc3df101475e3d0
diff --git a/imgdiag/imgdiag_test.cc b/imgdiag/imgdiag_test.cc
new file mode 100644
index 0000000..1ac7930
--- /dev/null
+++ b/imgdiag/imgdiag_test.cc
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string>
+#include <vector>
+#include <sstream>
+
+#include "common_runtime_test.h"
+
+#include "runtime/os.h"
+#include "runtime/arch/instruction_set.h"
+#include "runtime/utils.h"
+#include "runtime/gc/space/image_space.h"
+#include "runtime/gc/heap.h"
+#include "base/stringprintf.h"
+
+#include <sys/types.h>
+#include <unistd.h>
+
+namespace art {
+
+static const char* kImgDiagDiffPid = "--image-diff-pid";
+static const char* kImgDiagBootImage = "--boot-image";
+static const char* kImgDiagBinaryName = "imgdiag";
+
+class ImgDiagTest : public CommonRuntimeTest {
+ protected:
+  virtual void SetUp() {
+    CommonRuntimeTest::SetUp();
+
+    // We loaded the runtime with an explicit image. Therefore the image space must exist.
+    gc::space::ImageSpace* image_space = Runtime::Current()->GetHeap()->GetImageSpace();
+    ASSERT_TRUE(image_space != nullptr);
+    boot_image_location_ = image_space->GetImageLocation();
+  }
+
+  virtual void SetUpRuntimeOptions(RuntimeOptions* options) OVERRIDE {
+    // Needs to live until CommonRuntimeTest::SetUp finishes, since we pass it a cstring.
+    runtime_args_image_ = StringPrintf("-Ximage:%s", GetCoreArtLocation().c_str());
+    options->push_back(std::make_pair(runtime_args_image_, nullptr));
+  }
+
+  // Path to the imgdiag(d?)[32|64] binary.
+  std::string GetImgDiagFilePath() {
+    std::string root = GetTestAndroidRoot();
+
+    root += "/bin/";
+    root += kImgDiagBinaryName;
+
+    if (kIsDebugBuild) {
+      root += "d";
+    }
+
+    std::string root32 = root + "32";
+    // If we have both a 32-bit and a 64-bit build, the 32-bit file will have a 32 suffix.
+    if (OS::FileExists(root32.c_str()) && !Is64BitInstructionSet(kRuntimeISA)) {
+      return root32;
+    // Only a single build exists, so the filename never has an extra suffix.
+    } else {
+      return root;
+    }
+  }
+
+  // Run imgdiag with a custom boot image location.
+  bool Exec(pid_t image_diff_pid, const std::string& boot_image, std::string* error_msg) {
+    // Invoke 'img_diag' against the current process.
+    // This should succeed because we have a runtime and so it should
+    // be able to map in the boot.art and do a diff for it.
+    std::string file_path = GetImgDiagFilePath();
+    EXPECT_TRUE(OS::FileExists(file_path.c_str())) << file_path << " should be a valid file path";
+
+    // Run imgdiag --image-diff-pid=$image_diff_pid and wait until it's done with a 0 exit code.
+    std::string diff_pid_args;
+    {
+      std::stringstream diff_pid_args_ss;
+      diff_pid_args_ss << kImgDiagDiffPid << "=" << image_diff_pid;
+      diff_pid_args = diff_pid_args_ss.str();
+    }
+    std::string boot_image_args;
+    {
+      boot_image_args = boot_image_args + kImgDiagBootImage + "=" + boot_image;
+    }
+
+    std::vector<std::string> exec_argv = { file_path, diff_pid_args, boot_image_args };
+
+    return ::art::Exec(exec_argv, error_msg);
+  }
+
+  // Run imgdiag with the default boot image location.
+  bool ExecDefaultBootImage(pid_t image_diff_pid, std::string* error_msg) {
+    return Exec(image_diff_pid, boot_image_location_, error_msg);
+  }
+
+ private:
+  std::string runtime_args_image_;
+  std::string boot_image_location_;
+};
+
+#if defined (ART_TARGET)
+TEST_F(ImgDiagTest, ImageDiffPidSelf) {
+#else
+// Can't run this test on the host, it will fail when trying to open /proc/kpagestats
+// because it's root read-only.
+TEST_F(ImgDiagTest, DISABLED_ImageDiffPidSelf) {
+#endif
+  // Invoke 'img_diag' against the current process.
+  // This should succeed because we have a runtime and so it should
+  // be able to map in the boot.art and do a diff for it.
+
+  // Run imgdiag --image-diff-pid=$(self pid) and wait until it's done with a 0 exit code.
+  std::string error_msg;
+  ASSERT_TRUE(ExecDefaultBootImage(getpid(), &error_msg)) << "Failed to execute -- because: "
+                                                          << error_msg;
+}
+
+TEST_F(ImgDiagTest, ImageDiffBadPid) {
+  // Invoke 'img_diag' against a non-existing process. This should fail.
+
+  // Run imgdiag --image-diff-pid=some_bad_pid and wait until it's done with a 0 exit code.
+  std::string error_msg;
+  ASSERT_FALSE(ExecDefaultBootImage(-12345, &error_msg)) << "Incorrectly executed";
+  UNUSED(error_msg);
+}
+
+}  // namespace art