ART: CFI Test

Add a run-test that unwinds the process and a forked
process to see whether CFI information is enough
to see Java methods.

In-process unwinding is turned off for now, as it
requires dlopen for oat files.

Black-listed for 64-bit, as libunwind expects 64-bit
ELF files.

Change-Id: I9fe53e448b6cb2ea3d516526c42596dcc2446d98
diff --git a/test/137-cfi/cfi.cc b/test/137-cfi/cfi.cc
new file mode 100644
index 0000000..b2d7e55
--- /dev/null
+++ b/test/137-cfi/cfi.cc
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#if __linux__
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#endif
+
+#include "jni.h"
+
+#include <backtrace/Backtrace.h>
+
+#include "base/logging.h"
+#include "base/macros.h"
+#include "utils.h"
+
+namespace art {
+
+// For testing debuggerd. We do not have expected-death tests, so can't test this by default.
+// Code for this is copied from SignalTest.
+static constexpr bool kCauseSegfault = false;
+char* go_away_compiler_cfi = nullptr;
+
+static void CauseSegfault() {
+#if defined(__arm__) || defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
+  // On supported architectures we cause a real SEGV.
+  *go_away_compiler_cfi = 'a';
+#else
+  // On other architectures we simulate SEGV.
+  kill(getpid(), SIGSEGV);
+#endif
+}
+
+extern "C" JNIEXPORT jboolean JNICALL Java_Main_sleep(JNIEnv*, jobject, jint, jboolean, jdouble) {
+  // Keep pausing.
+  for (;;) {
+    pause();
+  }
+}
+
+// Helper to look for a sequence in the stack trace.
+#if __linux__
+static bool CheckStack(Backtrace* bt, const std::vector<std::string>& seq) {
+  size_t cur_search_index = 0;  // The currently active index in seq.
+  CHECK_GT(seq.size(), 0U);
+
+  for (Backtrace::const_iterator it = bt->begin(); it != bt->end(); ++it) {
+    if (BacktraceMap::IsValid(it->map)) {
+      LOG(INFO) << "Got " << it->func_name << ", looking for " << seq[cur_search_index];
+      if (it->func_name == seq[cur_search_index]) {
+        cur_search_index++;
+        if (cur_search_index == seq.size()) {
+          return true;
+        }
+      }
+    }
+  }
+
+  return false;
+}
+#endif
+
+extern "C" JNIEXPORT jboolean JNICALL Java_Main_unwindInProcess(JNIEnv*, jobject, jint, jboolean) {
+#if __linux__
+  // TODO: What to do on Valgrind?
+
+  std::unique_ptr<Backtrace> bt(Backtrace::Create(BACKTRACE_CURRENT_PROCESS, GetTid()));
+  if (!bt->Unwind(0, nullptr)) {
+    return JNI_FALSE;
+  } else if (bt->NumFrames() == 0) {
+    return JNI_FALSE;
+  }
+
+  // We cannot really parse an exact stack, as the optimizing compiler may inline some functions.
+  // This is also risky, as deduping might play a trick on us, so the test needs to make sure that
+  // only unique functions are being expected.
+  std::vector<std::string> seq = {
+      "Java_Main_unwindInProcess",                   // This function.
+      "boolean Main.unwindInProcess(int, boolean)",  // The corresponding Java native method frame.
+      "void Main.main(java.lang.String[])"           // The Java entry method.
+  };
+
+  bool result = CheckStack(bt.get(), seq);
+  if (!kCauseSegfault) {
+    return result ? JNI_TRUE : JNI_FALSE;
+  } else {
+    LOG(INFO) << "Result of check-stack: " << result;
+  }
+#endif
+
+  if (kCauseSegfault) {
+    CauseSegfault();
+  }
+
+  return JNI_FALSE;
+}
+
+#if __linux__
+static constexpr int kSleepTimeMicroseconds = 50000;            // 0.05 seconds
+static constexpr int kMaxTotalSleepTimeMicroseconds = 1000000;  // 1 second
+
+// Wait for a sigstop. This code is copied from libbacktrace.
+int wait_for_sigstop(pid_t tid, int* total_sleep_time_usec, bool* detach_failed ATTRIBUTE_UNUSED) {
+  for (;;) {
+    int status;
+    pid_t n = TEMP_FAILURE_RETRY(waitpid(tid, &status, __WALL | WNOHANG));
+    if (n == -1) {
+      PLOG(WARNING) << "waitpid failed: tid " << tid;
+      break;
+    } else if (n == tid) {
+      if (WIFSTOPPED(status)) {
+        return WSTOPSIG(status);
+      } else {
+        PLOG(ERROR) << "unexpected waitpid response: n=" << n << ", status=" << std::hex << status;
+        break;
+      }
+    }
+
+    if (*total_sleep_time_usec > kMaxTotalSleepTimeMicroseconds) {
+      PLOG(WARNING) << "timed out waiting for stop signal: tid=" << tid;
+      break;
+    }
+
+    usleep(kSleepTimeMicroseconds);
+    *total_sleep_time_usec += kSleepTimeMicroseconds;
+  }
+
+  return -1;
+}
+#endif
+
+extern "C" JNIEXPORT jboolean JNICALL Java_Main_unwindOtherProcess(JNIEnv*, jobject, jint pid_int) {
+#if __linux__
+  // TODO: What to do on Valgrind?
+  pid_t pid = static_cast<pid_t>(pid_int);
+
+  // OK, this is painful. debuggerd uses ptrace to unwind other processes.
+
+  if (ptrace(PTRACE_ATTACH, pid, 0, 0)) {
+    // Were not able to attach, bad.
+    PLOG(ERROR) << "Failed to attach.";
+    kill(pid, SIGCONT);
+    return JNI_FALSE;
+  }
+
+  kill(pid, SIGSTOP);
+
+  bool detach_failed = false;
+  int total_sleep_time_usec = 0;
+  int signal = wait_for_sigstop(pid, &total_sleep_time_usec, &detach_failed);
+  if (signal == -1) {
+    LOG(WARNING) << "wait_for_sigstop failed.";
+  }
+
+  std::unique_ptr<Backtrace> bt(Backtrace::Create(pid, BACKTRACE_CURRENT_THREAD));
+  bool result = true;
+  if (!bt->Unwind(0, nullptr)) {
+    result = false;
+  } else if (bt->NumFrames() == 0) {
+    result = false;
+  }
+
+  if (result) {
+    // See comment in unwindInProcess for non-exact stack matching.
+    std::vector<std::string> seq = {
+        // "Java_Main_sleep",                        // The sleep function being executed in the
+                                                     // other runtime.
+                                                     // Note: For some reason, the name isn't
+                                                     // resolved, so don't look for it right now.
+        "boolean Main.sleep(int, boolean, double)",  // The corresponding Java native method frame.
+        "void Main.main(java.lang.String[])"         // The Java entry method.
+    };
+
+    result = CheckStack(bt.get(), seq);
+  }
+
+  if (ptrace(PTRACE_DETACH, pid, 0, 0) != 0) {
+    PLOG(ERROR) << "Detach failed";
+  }
+
+  // Continue the process so we can kill it on the Java side.
+  kill(pid, SIGCONT);
+
+  return result ? JNI_TRUE : JNI_FALSE;
+#else
+  return JNI_FALSE;
+#endif
+}
+
+}  // namespace art
diff --git a/test/137-cfi/expected.txt b/test/137-cfi/expected.txt
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/test/137-cfi/expected.txt
diff --git a/test/137-cfi/info.txt b/test/137-cfi/info.txt
new file mode 100644
index 0000000..7d59605
--- /dev/null
+++ b/test/137-cfi/info.txt
@@ -0,0 +1 @@
+Test that unwinding with CFI info works.
diff --git a/test/137-cfi/src/Main.java b/test/137-cfi/src/Main.java
new file mode 100644
index 0000000..e184e66
--- /dev/null
+++ b/test/137-cfi/src/Main.java
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+public class Main {
+  // Whether to test local unwinding. Libunwind uses linker info to find executables. As we do
+  // not dlopen at the moment, this doesn't work, so keep it off for now.
+  public final static boolean TEST_LOCAL_UNWINDING = false;
+
+  // Unwinding another process, modelling debuggerd. This doesn't use the linker, so should work
+  // no matter whether we're using dlopen or not.
+  public final static boolean TEST_REMOTE_UNWINDING = true;
+
+  private boolean secondary;
+
+  public Main(boolean secondary) {
+      this.secondary = secondary;
+  }
+
+  public static void main(String[] args) throws Exception {
+      boolean secondary = false;
+      if (args.length > 0 && args[args.length - 1].equals("--secondary")) {
+          secondary = true;
+      }
+      new Main(secondary).run();
+  }
+
+  static {
+      System.loadLibrary("arttest");
+  }
+
+  private void run() {
+      if (secondary) {
+          if (!TEST_REMOTE_UNWINDING) {
+              throw new RuntimeException("Should not be running secondary!");
+          }
+          runSecondary();
+      } else {
+          runPrimary();
+      }
+  }
+
+  private void runSecondary() {
+      foo(true);
+      throw new RuntimeException("Didn't expect to get back...");
+  }
+
+  private void runPrimary() {
+      // First do the in-process unwinding.
+      if (TEST_LOCAL_UNWINDING && !foo(false)) {
+          System.out.println("Unwinding self failed.");
+      }
+
+      if (!TEST_REMOTE_UNWINDING) {
+          // Skip the remote step.
+          return;
+      }
+
+      // Fork the secondary.
+      String[] cmdline = getCmdLine();
+      String[] secCmdLine = new String[cmdline.length + 1];
+      System.arraycopy(cmdline, 0, secCmdLine, 0, cmdline.length);
+      secCmdLine[secCmdLine.length - 1] = "--secondary";
+      Process p = exec(secCmdLine);
+
+      try {
+          int pid = getPid(p);
+          if (pid <= 0) {
+              throw new RuntimeException("Couldn't parse process");
+          }
+
+          // Wait a bit, so the forked process has time to run until its sleep phase.
+          try {
+              Thread.sleep(5000);
+          } catch (Exception e) {
+              throw new RuntimeException(e);
+          }
+
+          if (!unwindOtherProcess(pid)) {
+              System.out.println("Unwinding other process failed.");
+          }
+      } finally {
+          // Kill the forked process.
+          p.destroy();
+      }
+  }
+
+  private static Process exec(String[] args) {
+      try {
+          return Runtime.getRuntime().exec(args);
+      } catch (Exception exc) {
+          throw new RuntimeException(exc);
+      }
+  }
+
+  private static int getPid(Process p) {
+      // Could do reflection for the private pid field, but String parsing is easier.
+      String s = p.toString();
+      if (s.startsWith("Process[pid=")) {
+          return Integer.parseInt(s.substring("Process[pid=".length(), s.length() - 1));
+      } else {
+          return -1;
+      }
+  }
+
+  // Read /proc/self/cmdline to find the invocation command line (so we can fork another runtime).
+  private static String[] getCmdLine() {
+      try {
+          BufferedReader in = new BufferedReader(new FileReader("/proc/self/cmdline"));
+          String s = in.readLine();
+          in.close();
+          return s.split("\0");
+      } catch (Exception exc) {
+          throw new RuntimeException(exc);
+      }
+  }
+
+  public boolean foo(boolean b) {
+      return bar(b);
+  }
+
+  public boolean bar(boolean b) {
+      if (b) {
+          return sleep(2, b, 1.0);
+      } else {
+          return unwindInProcess(1, b);
+      }
+  }
+
+  // Native functions. Note: to avoid deduping, they must all have different signatures.
+
+  public native boolean sleep(int i, boolean b, double dummy);
+
+  public native boolean unwindInProcess(int i, boolean b);
+  public native boolean unwindOtherProcess(int pid);
+}
diff --git a/test/Android.libarttest.mk b/test/Android.libarttest.mk
index 5e768ee..6abcadf 100644
--- a/test/Android.libarttest.mk
+++ b/test/Android.libarttest.mk
@@ -28,6 +28,7 @@
   116-nodex2oat/nodex2oat.cc \
   117-nopatchoat/nopatchoat.cc \
   118-noimage-dex2oat/noimage-dex2oat.cc \
+  137-cfi/cfi.cc \
   454-get-vreg/get_vreg_jni.cc \
   455-set-vreg/set_vreg_jni.cc \
   457-regs/regs_jni.cc \
@@ -56,7 +57,7 @@
     LOCAL_MODULE_TAGS := tests
   endif
   LOCAL_SRC_FILES := $(LIBARTTEST_COMMON_SRC_FILES)
-  LOCAL_SHARED_LIBRARIES += libartd
+  LOCAL_SHARED_LIBRARIES += libartd libbacktrace
   LOCAL_C_INCLUDES += $(ART_C_INCLUDES) art/runtime
   LOCAL_ADDITIONAL_DEPENDENCIES := art/build/Android.common_build.mk
   LOCAL_ADDITIONAL_DEPENDENCIES += $(LOCAL_PATH)/Android.libarttest.mk
diff --git a/test/Android.run-test.mk b/test/Android.run-test.mk
index 07e7620..986276d 100644
--- a/test/Android.run-test.mk
+++ b/test/Android.run-test.mk
@@ -323,6 +323,7 @@
   118-noimage-dex2oat \
   119-noimage-patchoat \
   131-structural-change \
+  137-cfi \
   454-get-vreg \
   455-set-vreg \
   457-regs \
@@ -438,6 +439,11 @@
 
 TEST_ART_BROKEN_READ_BARRIER_RUN_TESTS :=
 
+# Test 137-cfi works in 32-bit only until we enable 64-bit ELF files.
+ART_TEST_KNOWN_BROKEN += $(call all-run-test-names,$(TARGET_TYPES),$(RUN_TYPES),$(PREBUILD_TYPES), \
+    $(COMPILER_TYPES),$(RELOCATE_TYPES),$(TRACE_TYPES),$(GC_TYPES),$(JNI_TYPES), \
+    $(IMAGE_TYPES),$(PICTEST_TYPES),$(DEBUGGABLE_TYPES),137-cfi,64)
+
 # Clear variables ahead of appending to them when defining tests.
 $(foreach target, $(TARGET_TYPES), $(eval ART_RUN_TEST_$(call name-to-var,$(target))_RULES :=))
 $(foreach target, $(TARGET_TYPES), \