Add cross-process coverage flushing for the LLVM toolchain.

Bug: 143977934
Test: Build with native coverage
Test: kill -37 <pid> and check for coverage in /data/misc/trace
Change-Id: Iadf93e62d92dc35cdaa35162ca4a75d26190db85

diff --git a/toolchain-extras/Android.bp b/toolchain-extras/Android.bp
index 7cc9734..d9bf6a4 100644 (file)
--- a/toolchain-extras/Android.bp
+++ b/toolchain-extras/Android.bp
@@ -35,6 +35,42 @@ cc_library_static {
     sdk_version: "minimum",
 }
 
+cc_defaults {
+    name: "libprofile-clang-defaults",
+    srcs: [
+        "profile-clang-extras.cpp",
+    ],
+    native_coverage: false,
+}
+
+cc_library_static {
+    name: "libprofile-clang-extras",
+    defaults: ["libprofile-clang-defaults"],
+
+    native_bridge_supported: true,
+    vendor_available: true,
+    vndk: {
+        enabled: true,
+    },
+    recovery_available: true,
+
+    stl: "none",
+    system_shared_libs: [],
+    header_libs: ["libc_headers"],
+}
+
+cc_library_static {
+    name: "libprofile-clang-extras_ndk",
+    defaults: ["libprofile-clang-defaults"],
+    native_bridge_supported: true,
+    vendor_available: true,
+    vndk: {
+        enabled: true,
+    },
+
+    sdk_version: "minimum",
+}
+
 cc_test {
     name: "libprofile-extras-test",
     srcs: [

diff --git a/toolchain-extras/profile-clang-extras-test.cpp b/toolchain-extras/profile-clang-extras-test.cpp
new file mode 100644 (file)
index 0000000..2bb7bdb
--- /dev/null
+++ b/toolchain-extras/profile-clang-extras-test.cpp
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2020 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 <gtest/gtest.h>
+#include "profile-extras.h"
+
+static int flush_count = 0;
+
+extern "C" {
+int __llvm_profile_write_file() {
+  flush_count++;
+  return 0;
+}
+}
+
+TEST(profile_extras, smoke) {
+  flush_count = 0;
+
+  ASSERT_EQ(0, flush_count);
+  kill(getpid(), GCOV_FLUSH_SIGNAL);
+  sleep(2);
+  ASSERT_EQ(1, flush_count);
+}

diff --git a/toolchain-extras/profile-clang-extras.cpp b/toolchain-extras/profile-clang-extras.cpp
new file mode 100644 (file)
index 0000000..89c18b2
--- /dev/null
+++ b/toolchain-extras/profile-clang-extras.cpp
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2020 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 <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+
+#include "profile-extras.h"
+
+extern "C" {
+
+static sighandler_t chained_signal_handler = SIG_ERR;
+
+int __llvm_profile_write_file(void);
+
+static void llvm_signal_handler(__unused int signum) {
+  __llvm_profile_write_file();
+
+  if (chained_signal_handler != SIG_ERR &&
+      chained_signal_handler != SIG_IGN &&
+      chained_signal_handler != SIG_DFL) {
+    (chained_signal_handler)(signum);
+  }
+}
+
+__attribute__((weak)) int init_profile_extras_once = 0;
+
+// Initialize libprofile-extras:
+// - Install a signal handler that triggers __llvm_profile_write_file on <COVERAGE_FLUSH_SIGNAL>.
+//
+// We want this initializer to run during load time.
+//
+// Just marking init_profile_extras() with __attribute__((constructor)) isn't
+// enough since the linker drops it from its output since no other symbol from
+// this static library is referenced.
+//
+// We force the linker to include init_profile_extras() by passing
+// '-uinit_profile_extras' to the linker (in build/soong).
+__attribute__((constructor)) int init_profile_extras(void) {
+  if (init_profile_extras_once)
+    return 0;
+  init_profile_extras_once = 1;
+
+  if (chained_signal_handler != SIG_ERR) {
+    return -1;
+  }
+  sighandler_t ret1 = signal(COVERAGE_FLUSH_SIGNAL, llvm_signal_handler);
+  if (ret1 == SIG_ERR) {
+    return -1;
+  }
+  chained_signal_handler = ret1;
+
+  return 0;
+}
+}

diff --git a/toolchain-extras/profile-extras-test.cpp b/toolchain-extras/profile-extras-test.cpp
index 5e48a64..0e52f15 100644 (file)
--- a/toolchain-extras/profile-extras-test.cpp
+++ b/toolchain-extras/profile-extras-test.cpp
@@ -34,7 +34,7 @@ TEST(profile_extras, smoke) {
   flush_count = 0;
 
   ASSERT_EQ(0, flush_count);
-  kill(getpid(), GCOV_FLUSH_SIGNAL);
+  kill(getpid(), COVERAGE_FLUSH_SIGNAL);
   sleep(2);
   ASSERT_EQ(1, flush_count);
 

diff --git a/toolchain-extras/profile-extras.cpp b/toolchain-extras/profile-extras.cpp
index 7d78a0a..d2a541c 100644 (file)
--- a/toolchain-extras/profile-extras.cpp
+++ b/toolchain-extras/profile-extras.cpp
@@ -92,7 +92,7 @@ static size_t prop_watch_num_disabled_procs = \
 __attribute__((weak)) int init_profile_extras_once = 0;
 
 // Initialize libprofile-extras:
-// - Install a signal handler that triggers __gcov_flush on <GCOV_FLUSH_SIGNAL>.
+// - Install a signal handler that triggers __gcov_flush on <COVERAGE_FLUSH_SIGNAL>.
 // - Create a thread that calls __gcov_flush when <kCoveragePropName> sysprop
 // transistions to "1" after a transistion to "0".
 //
@@ -113,7 +113,7 @@ __attribute__((constructor)) int init_profile_extras(void) {
   if (chained_gcov_signal_handler != SIG_ERR) {
     return -1;
   }
-  sighandler_t ret1 = signal(GCOV_FLUSH_SIGNAL, gcov_signal_handler);
+  sighandler_t ret1 = signal(COVERAGE_FLUSH_SIGNAL, gcov_signal_handler);
   if (ret1 == SIG_ERR) {
     return -1;
   }

diff --git a/toolchain-extras/profile-extras.h b/toolchain-extras/profile-extras.h
index 3e217ea..5b20618 100644 (file)
--- a/toolchain-extras/profile-extras.h
+++ b/toolchain-extras/profile-extras.h
@@ -16,4 +16,4 @@
 
 #include <signal.h>
 
-#define GCOV_FLUSH_SIGNAL (__SIGRTMIN + 5)
+#define COVERAGE_FLUSH_SIGNAL (__SIGRTMIN + 5)