Integrate ART with NativeBridge interfaces

Native-bridge will provide the following interfaces to ART:

struct NativeBridgeCallbacks {
  bool  (*initialize   )(NativeBridgeArtCallbacks* vm_itf);
  void* (*loadLibrary  )(const char* libpath, int flag);
  void* (*getTrampoline)(void* handle, const char* name, const char* shorty,
                         uint32_t len);
  bool  (*isSupported  )(const char* libpath);
};

Native-bridge will expose a symbol NativeBridgeItf with the
type of NativeBridgeCallbacks to ART.

And ART will provide the interfaces below to native-bridge:

struct NativeBridgeArtCallbacks {
  int   (*logger               )(int prio, const char* tag, const char* fmt, ...);
  const char* (*getMethodShorty)(JNIEnv* env, jmethodID mid);
  int   (*getNativeMethodCount )(JNIEnv* env, jclass clazz);
  int   (*getNativeMethods     )(JNIEnv* env, jclass clazz, JNINativeMethod* methods,
                                 uint32_t method_count);
};

Based on the interfaces, if an ART call to dlopen fails to open a native library,
it queries the native bridge by using NativeBridgeCallbacks::isSupported(). If the
native library is supported by native-bridge, ART can load the native library
using NativeBridgeCallbacks::loadLibrary() and get a trampoline for a specific
native method using NativeBridgeCallbacks::getTrampoline(). ART can then call
the native method using the normal signature and the address of the trampoline.

On the other side, in the case of a native method calling JNI native function
CallXXXXMethodY(), native-bridge calls back to Art for the shorty of the method
using NativeBridgeArtCallbacks::getMethodShorty() so that it can prepare based
on host calling convention.

In case of JNI function RegisterNatives()/UnregisterNatives(), native bridge can
call back to NativeBridgeArtCallbacks::getNativeMethodCount() and NativeBridgeArtCallbacks
::getNativeMethods() to get all native methods of specified class so that all
corresponding trampolines can be prepared/destroyed.

Class NativeBridge is created to encapsulate the function pointers of
NativeBridgeCallbacks and provides better abstraction to ART.

Note: functionality is turned off in native_bridge.cc at the moment.

Change-Id: I652755044957a7960254648652b538cce70dd011

1 files changed, 53 insertions, 5 deletions

diff --git a/runtime/jni_internal.cc b/runtime/jni_internal.cc
index f9c7ec6..64cca3d 100644
--- a/runtime/jni_internal.cc
+++ b/runtime/jni_internal.cc
@@ -41,6 +41,7 @@
 #include "mirror/object_array-inl.h"
 #include "mirror/string-inl.h"
 #include "mirror/throwable.h"
+#include "native_bridge.h"
 #include "parsed_options.h"
 #include "reflection.h"
 #include "runtime.h"
@@ -362,6 +363,7 @@ class SharedLibrary {
   SharedLibrary(const std::string& path, void* handle, mirror::Object* class_loader)
       : path_(path),
         handle_(handle),
+        needs_native_bridge_(false),
         class_loader_(class_loader),
         jni_on_load_lock_("JNI_OnLoad lock"),
         jni_on_load_cond_("JNI_OnLoad condition variable", jni_on_load_lock_),
@@ -422,10 +424,30 @@ class SharedLibrary {
     jni_on_load_cond_.Broadcast(self);
   }
 
+  void SetNeedsNativeBridge() {
+    needs_native_bridge_ = true;
+  }
+
+  bool NeedsNativeBridge() const {
+    return needs_native_bridge_;
+  }
+
   void* FindSymbol(const std::string& symbol_name) {
     return dlsym(handle_, symbol_name.c_str());
   }
 
+  void* FindSymbolWithNativeBridge(const std::string& symbol_name, mirror::ArtMethod* m)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    CHECK(NeedsNativeBridge());
+
+    uint32_t len = 0;
+    const char* shorty = nullptr;
+    if (m != nullptr) {
+      shorty = m->GetShorty(&len);
+    }
+    return NativeBridge::GetTrampoline(handle_, symbol_name.c_str(), shorty, len);
+  }
+
   void VisitRoots(RootCallback* visitor, void* arg) {
     if (class_loader_ != nullptr) {
       visitor(&class_loader_, arg, 0, kRootVMInternal);
@@ -445,6 +467,9 @@ class SharedLibrary {
   // The void* returned by dlopen(3).
   void* handle_;
 
+  // True if a native bridge is required.
+  bool needs_native_bridge_;
+
   // The ClassLoader this library is associated with.
   mirror::Object* class_loader_;
 
@@ -505,9 +530,17 @@ class Libraries {
         continue;
       }
       // Try the short name then the long name...
-      void* fn = library->FindSymbol(jni_short_name);
-      if (fn == nullptr) {
-        fn = library->FindSymbol(jni_long_name);
+      void* fn = nullptr;
+      if (UNLIKELY(library->NeedsNativeBridge())) {
+        fn = library->FindSymbolWithNativeBridge(jni_short_name, m);
+        if (fn == nullptr) {
+          fn = library->FindSymbolWithNativeBridge(jni_long_name, m);
+        }
+      } else {
+        fn = library->FindSymbol(jni_short_name);
+        if (fn == nullptr) {
+          fn = library->FindSymbol(jni_long_name);
+        }
       }
       if (fn != nullptr) {
         VLOG(jni) << "[Found native code for " << PrettyMethod(m)
@@ -3267,7 +3300,15 @@ bool JavaVMExt::LoadNativeLibrary(const std::string& path,
   // This can execute slowly for a large library on a busy system, so we
   // want to switch from kRunnable while it executes.  This allows the GC to ignore us.
   self->TransitionFromRunnableToSuspended(kWaitingForJniOnLoad);
-  void* handle = dlopen(path.empty() ? nullptr : path.c_str(), RTLD_LAZY);
+  const char* path_str = path.empty() ? nullptr : path.c_str();
+  void* handle = dlopen(path_str, RTLD_LAZY);
+  bool needs_native_bridge = false;
+  if (handle == nullptr) {
+    if (NativeBridge::IsSupported(path_str)) {
+      handle = NativeBridge::LoadLibrary(path_str, RTLD_LAZY);
+      needs_native_bridge = true;
+    }
+  }
   self->TransitionFromSuspendedToRunnable();
 
   VLOG(jni) << "[Call to dlopen(\"" << path << "\", RTLD_LAZY) returned " << handle << "]";
@@ -3300,7 +3341,14 @@ bool JavaVMExt::LoadNativeLibrary(const std::string& path,
       << "]";
 
   bool was_successful = false;
-  void* sym = dlsym(handle, "JNI_OnLoad");
+  void* sym = nullptr;
+  if (UNLIKELY(needs_native_bridge)) {
+    library->SetNeedsNativeBridge();
+    sym = library->FindSymbolWithNativeBridge("JNI_OnLoad", nullptr);
+  } else {
+    sym = dlsym(handle, "JNI_OnLoad");
+  }
+
   if (sym == nullptr) {
     VLOG(jni) << "[No JNI_OnLoad found in \"" << path << "\"]";
     was_successful = true;