Enable shared object merging

dreiss · dreiss · commit 39a87f27b0a6 · 2018-01-18T16:32:44.000-08:00
diff --git a/apps/BUCK b/apps/BUCK
@@ -1,16 +1,24 @@
-android_binary(
+include_defs("//bucklets/DEFS")
+
+my_android_binary(
     name = "mammals",
     manifest_skeleton = "mammals-app-manifest.xml",
     keystore = ":debug_keystore",
+    native_library_merge_map = {
+        "libeverything.so": [".*"],
+    },
     deps = [
         "//src/com/facebook/example/mammals/activity:activity",
     ],
 )
 
-android_binary(
+my_android_binary(
     name = "animals",
     manifest_skeleton = "animals-app-manifest.xml",
     keystore = ":debug_keystore",
+    native_library_merge_map = {
+        "libeverything.so": [".*"],
+    },
     deps = [
         "//src/com/facebook/example/animals:animals",
     ],
diff --git a/bucklets/DEFS b/bucklets/DEFS
@@ -0,0 +1,33 @@
+def my_android_binary(**kwargs):
+    if "native_library_merge_map" in kwargs:
+        kwargs["native_library_merge_glue"] = "//src/com/facebook/jnimerge:glue"
+        kwargs["native_library_merge_code_generator"] = "//src/com/facebook/jnimerge:code-generator"
+        kwargs["native_library_merge_localized_symbols"] = [
+            "__start_pre_merge_jni_libraries",
+            "__stop_pre_merge_jni_libraries",
+        ]
+    else:
+        kwargs["deps"] = kwargs["deps"] + ["//src/com/facebook/soloader:mapping-stub"]
+    android_binary(**kwargs)
+
+
+def my_cxx_library(**kwargs):
+    if kwargs.pop("allow_jni_merging", None):
+        if "soname" not in kwargs:
+            raise Exception(
+                "JNI merging currently requires an explicit soname, "
+                "but %s doesn't have one."
+                % kwargs["name"])
+        kwargs["deps"] = kwargs.get("deps", []) + ["//src/com/facebook/jnimerge:jnimerge"]
+        kwargs["platform_preprocessor_flags"] = \
+            kwargs.get("platform_preprocessor_flags", []) + [
+                (r'.*\bandroid\b.*', [
+                    '-DORIGINAL_SONAME="%s"' % kwargs["soname"].replace("$(ext)", "so"),
+                    "-include", "jni_lib_merge.h",
+                ])]
+        kwargs["platform_linker_flags"] = kwargs.get("platform_linker_flags", []) + [
+            (r'.*\bandroid\b.*', [
+                "-Wl,--defsym=JNI_OnLoad=JNI_OnLoad_Weak",
+            ])]
+    cxx_library(**kwargs)
+
diff --git a/src/com/facebook/example/animals/BUCK b/src/com/facebook/example/animals/BUCK
@@ -6,6 +6,7 @@ android_library(
         "//src/com/facebook/example/animals/jni:jni",
         "//src/com/facebook/example/habitat:habitat",
         "//src/com/facebook/example/mammals:mammals",
+        "//src/com/facebook/soloader:soloader",
     ],
     visibility = ["PUBLIC"],
 )
diff --git a/src/com/facebook/example/animals/Penguin.java b/src/com/facebook/example/animals/Penguin.java
@@ -17,10 +17,11 @@
 package com.facebook.example.animals;
 
 import com.facebook.example.habitat.Ice;
+import com.facebook.soloader.SoLoader;
 
 public class Penguin {
   static {
-    System.loadLibrary("animals");
+    SoLoader.loadLibrary("animals");
   }
 
   public static String getDescription() {
diff --git a/src/com/facebook/example/animals/jni/BUCK b/src/com/facebook/example/animals/jni/BUCK
@@ -1,6 +1,9 @@
-cxx_library(
+include_defs("//bucklets/DEFS")
+
+my_cxx_library(
     name = "jni",
     soname = "libanimals.$(ext)",
+    allow_jni_merging = True,
     srcs = glob(["*.c"]),
     visibility = [
         "//src/com/facebook/example/animals:animals",
diff --git a/src/com/facebook/example/habitat/BUCK b/src/com/facebook/example/habitat/BUCK
@@ -3,6 +3,7 @@ java_library(
     srcs = glob(["*.java"]),
     deps = [
         "//src/com/facebook/example/habitat/jni:jni",
+        "//src/com/facebook/soloader:soloader",
     ],
     visibility = ["PUBLIC"],
 )
diff --git a/src/com/facebook/example/habitat/Ice.java b/src/com/facebook/example/habitat/Ice.java
@@ -16,9 +16,11 @@
 
 package com.facebook.example.habitat;
 
+import com.facebook.soloader.SoLoader;
+
 public class Ice {
   static {
-    System.loadLibrary("habitat");
+    SoLoader.loadLibrary("habitat");
   }
 
   private static int dxWorkaround = 0;
diff --git a/src/com/facebook/example/habitat/jni/BUCK b/src/com/facebook/example/habitat/jni/BUCK
@@ -1,6 +1,9 @@
-cxx_library(
+include_defs("//bucklets/DEFS")
+
+my_cxx_library(
     name = "jni",
     soname = "libhabitat.$(ext)",
+    allow_jni_merging = True,
     srcs = glob(["*.c"]),
     visibility = [
         "//src/com/facebook/example/habitat:habitat",
diff --git a/src/com/facebook/example/mammals/BUCK b/src/com/facebook/example/mammals/BUCK
@@ -3,6 +3,7 @@ java_library(
     srcs = glob(["*.java"]),
     deps = [
         "//src/com/facebook/example/mammals/jni:jni",
+        "//src/com/facebook/soloader:soloader",
     ],
     visibility = ["PUBLIC"],
 )
diff --git a/src/com/facebook/example/mammals/SeaLion.java b/src/com/facebook/example/mammals/SeaLion.java
@@ -16,9 +16,11 @@
 
 package com.facebook.example.mammals;
 
+import com.facebook.soloader.SoLoader;
+
 public class SeaLion {
   static {
-    System.loadLibrary("mammals");
+    SoLoader.loadLibrary("mammals");
   }
 
   public static String getDescription() {
diff --git a/src/com/facebook/example/mammals/jni/BUCK b/src/com/facebook/example/mammals/jni/BUCK
@@ -1,6 +1,9 @@
-cxx_library(
+include_defs("//bucklets/DEFS")
+
+my_cxx_library(
     name = "jni",
     soname = "libmammals.$(ext)",
+    allow_jni_merging = True,
     srcs = glob(["*.c"]),
     visibility = [
         "//src/com/facebook/example/mammals:mammals",
diff --git a/src/com/facebook/jnimerge/BUCK b/src/com/facebook/jnimerge/BUCK
@@ -0,0 +1,34 @@
+python_library(
+    name = "code-gen-lib",
+    srcs = ["map_code_generator.py"],
+)
+
+python_binary(
+    name = "code-generator",
+    main_module = "src.com.facebook.jnimerge.map_code_generator",
+    visibility = ["PUBLIC"],
+    deps = [
+        ":code-gen-lib",
+    ],
+)
+
+cxx_library(
+    name = "jnimerge",
+    exported_headers = [
+        "jni_lib_merge.h",
+    ],
+    header_namespace = "",
+    visibility = ["PUBLIC"],
+)
+
+cxx_library(
+    name = "glue",
+    srcs = [
+        "jni_lib_merge.c",
+    ],
+    force_static = True,
+    headers = [
+        "jni_lib_merge.h",
+    ],
+    visibility = ["PUBLIC"],
+)
diff --git a/src/com/facebook/jnimerge/jni_lib_merge.c b/src/com/facebook/jnimerge/jni_lib_merge.c
@@ -0,0 +1,128 @@
+/*
+ * Copyright 2018-present, Facebook, Inc.
+ *
+ * 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.
+ */
+
+// To be linked into merged libraries.
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+
+#include <jni.h>
+
+#include "jni_lib_merge.h"
+// We define JNI_OnLoad_Weak directly, so this macro doesn't hurt anything,
+// but undef it anyway just to avoid possible future confusion.
+#undef JNI_OnLoad
+#define PRINT(...) JNI_MERGE_PRINT(__VA_ARGS__)
+
+// Class with mapping that will be generated by buck.
+static const char* invoke_class_name =
+  "com/facebook/soloader/MergedSoMapping$Invoke_JNI_OnLoad";
+
+// Stub pre-merged library to ensure that our custom section gets created
+// when we merge a group of native libraries with no JNI_OnLoad.
+static struct pre_merge_jni_library pmjl_stub
+__attribute__ ((__section__("pre_merge_jni_libraries")))
+= {
+  .name = "jni_lib_merge-stub",
+  .onload_func = NULL,
+};
+
+// References to custom section bounds, filled in by linker.
+extern struct pre_merge_jni_library __start_pre_merge_jni_libraries;
+extern struct pre_merge_jni_library __stop_pre_merge_jni_libraries;
+
+
+// Returns a malloc'ed string.
+static char* method_name_for_invoke(const char* soname) {
+  char* name = strdup(soname);
+  if (!name) {
+    // Can't log here, since we don't know if we're depending on Android logging.
+    assert(!"Failed to strdup soname.");
+    abort();
+  }
+  for (char* c = name; *c != '\0'; ++c) {
+    if (!isalnum(*c) && *c != '_') {
+      *c = '_';
+    }
+  }
+  return name;
+}
+
+
+// Replacement for weak JNI_OnLoad.
+jint JNI_OnLoad_Weak(JavaVM* vm, void* reserved) {
+  (void)reserved;
+
+  PRINT("Entering merged library JNI_OnLoad.\n");
+
+  // Get the JNI Env so we can register the original JNI_OnLoad methods.
+  JNIEnv* env;
+  if ((*vm)->GetEnv(vm, (void**)&env, JNI_VERSION_1_2) != JNI_OK) {
+    return JNI_ERR;
+  }
+
+  // Find the class we need to register with.
+  jclass invoke_class = (*env)->FindClass(env, invoke_class_name);
+  if (invoke_class == NULL) {
+    return JNI_ERR;
+  }
+
+  // Construct the argument to RegisterNatives with proper sanitized names
+  // and function pointers.
+  struct pre_merge_jni_library* start = &__start_pre_merge_jni_libraries;
+  struct pre_merge_jni_library* stop = &__stop_pre_merge_jni_libraries;
+  size_t num_merged_libraries = stop - start;
+  PRINT("Preparing %d pre-merged libs (including stub)\n", num_merged_libraries);
+  JNINativeMethod* natives = calloc(num_merged_libraries, sizeof(*natives));
+  assert(natives != NULL);
+  if (natives == NULL) {
+    abort();
+  }
+  JNINativeMethod* cur_native = natives;
+  struct pre_merge_jni_library* pmjl = start;
+  for (size_t i = 0; i < num_merged_libraries; i++, pmjl++) {
+    if (pmjl == &pmjl_stub) {
+      continue;
+    }
+    char* name = method_name_for_invoke(pmjl->name);
+    PRINT("Preparing to register %s.  onload_func: %p\n", name, pmjl->onload_func);
+
+    cur_native->name = name;
+    cur_native->signature = "()I";
+    cur_native->fnPtr = pmjl->onload_func;
+    cur_native++;
+  }
+
+  size_t num_actual_methods = cur_native - natives;
+  PRINT("About to register %d actual methods.\n", num_actual_methods);
+  jint ret = (*env)->RegisterNatives(env, invoke_class, natives, num_actual_methods);
+
+  for (size_t i = 0; i < num_actual_methods; i++) {
+    free((void*)natives[i].name);
+  }
+  free(natives);
+
+  if (ret < 0) {
+    // Exception already thrown.
+    return JNI_ERR;
+  }
+
+  return JNI_VERSION_1_6;
+}
diff --git a/src/com/facebook/jnimerge/jni_lib_merge.h b/src/com/facebook/jnimerge/jni_lib_merge.h
diff --git a/src/com/facebook/jnimerge/map_code_generator.py b/src/com/facebook/jnimerge/map_code_generator.py
diff --git a/src/com/facebook/soloader/BUCK b/src/com/facebook/soloader/BUCK
diff --git a/src/com/facebook/soloader/MergedSoMapping.java b/src/com/facebook/soloader/MergedSoMapping.java
diff --git a/src/com/facebook/soloader/SoLoader.java b/src/com/facebook/soloader/SoLoader.java
