JDWP: fix breakpoint for method in the image
When we set a breakpoint in a compiled method, we deoptimize it by
changing its entrypoint so it is executed with the interpreter.
However, methods in the image can be called with their direct code
pointer, ignoring the updated entrypoint. In that case, the method
is not executed with the interpreter and we miss the breakpoint.
This CL avoids that situation by forcing a full deoptimization so
everything runs with the interpreter. However, if the image has been
compiled in PIC mode, we keep using selective deoptimization because
direct code pointer is not used in this mode.
Bug: 17965285
Change-Id: Icaf8cbb7fe9ad01d36f7378c59d50d9ce42ae57f
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index f092772..7a8e4a3 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -5926,4 +5926,34 @@
return ComputeModifiedUtf8Hash(descriptor);
}
+bool ClassLinker::MayBeCalledWithDirectCodePointer(mirror::ArtMethod* m) {
+ // Non-image methods don't use direct code pointer.
+ if (!m->GetDeclaringClass()->IsBootStrapClassLoaded()) {
+ return false;
+ }
+ if (m->IsPrivate()) {
+ // The method can only be called inside its own oat file. Therefore it won't be called using
+ // its direct code if the oat file has been compiled in PIC mode.
+ ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
+ const DexFile& dex_file = m->GetDeclaringClass()->GetDexFile();
+ const OatFile::OatDexFile* oat_dex_file = class_linker->FindOpenedOatDexFileForDexFile(dex_file);
+ if (oat_dex_file == nullptr) {
+ // No oat file: the method has not been compiled.
+ return false;
+ }
+ const OatFile* oat_file = oat_dex_file->GetOatFile();
+ return oat_file != nullptr && !oat_file->IsPic();
+ } else {
+ // The method can be called outside its own oat file. Therefore it won't be called using its
+ // direct code pointer only if all loaded oat files have been compiled in PIC mode.
+ ReaderMutexLock mu(Thread::Current(), dex_lock_);
+ for (const OatFile* oat_file : oat_files_) {
+ if (!oat_file->IsPic()) {
+ return true;
+ }
+ }
+ return false;
+ }
+}
+
} // namespace art
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index b78d0b5..55332f8 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -471,6 +471,10 @@
LOCKS_EXCLUDED(Locks::classlinker_classes_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+ // Returns true if the method can be called with its direct code pointer, false otherwise.
+ bool MayBeCalledWithDirectCodePointer(mirror::ArtMethod* m)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
private:
const OatFile::OatMethod FindOatMethodFor(mirror::ArtMethod* method, bool* found)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
diff --git a/runtime/class_linker_test.cc b/runtime/class_linker_test.cc
index 99d0746..c22c51e 100644
--- a/runtime/class_linker_test.cc
+++ b/runtime/class_linker_test.cc
@@ -1141,4 +1141,24 @@
CheckPreverified(statics.Get(), true);
}
+TEST_F(ClassLinkerTest, IsBootStrapClassLoaded) {
+ ScopedObjectAccess soa(Thread::Current());
+
+ StackHandleScope<3> hs(soa.Self());
+ Handle<mirror::ClassLoader> class_loader(
+ hs.NewHandle(soa.Decode<mirror::ClassLoader*>(LoadDex("Statics"))));
+
+ // java.lang.Object is a bootstrap class.
+ Handle<mirror::Class> jlo_class(
+ hs.NewHandle(class_linker_->FindSystemClass(soa.Self(), "Ljava/lang/Object;")));
+ ASSERT_TRUE(jlo_class.Get() != nullptr);
+ EXPECT_TRUE(jlo_class.Get()->IsBootStrapClassLoaded());
+
+ // Statics is not a bootstrap class.
+ Handle<mirror::Class> statics(
+ hs.NewHandle(class_linker_->FindClass(soa.Self(), "LStatics;", class_loader)));
+ ASSERT_TRUE(statics.Get() != nullptr);
+ EXPECT_FALSE(statics.Get()->IsBootStrapClassLoaded());
+}
+
} // namespace art
diff --git a/runtime/debugger.cc b/runtime/debugger.cc
index 49b132d..86d027b 100644
--- a/runtime/debugger.cc
+++ b/runtime/debugger.cc
@@ -3266,8 +3266,16 @@
ClassLinker* const class_linker = Runtime::Current()->GetClassLinker();
const bool is_compiled = class_linker->GetOatMethodQuickCodeFor(m) != nullptr;
if (is_compiled) {
- VLOG(jdwp) << "Need selective deoptimization for compiled method " << PrettyMethod(m);
- return DeoptimizationRequest::kSelectiveDeoptimization;
+ // If the method may be called through its direct code pointer (without loading
+ // its updated entrypoint), we need full deoptimization to not miss the breakpoint.
+ if (class_linker->MayBeCalledWithDirectCodePointer(m)) {
+ VLOG(jdwp) << "Need full deoptimization because of possible direct code call "
+ << "into image for compiled method " << PrettyMethod(m);
+ return DeoptimizationRequest::kFullDeoptimization;
+ } else {
+ VLOG(jdwp) << "Need selective deoptimization for compiled method " << PrettyMethod(m);
+ return DeoptimizationRequest::kSelectiveDeoptimization;
+ }
} else {
// Method is not compiled: we don't need to deoptimize.
VLOG(jdwp) << "No need for deoptimization for non-compiled method " << PrettyMethod(m);
diff --git a/runtime/mirror/class.h b/runtime/mirror/class.h
index a77972e..2fc5ffb 100644
--- a/runtime/mirror/class.h
+++ b/runtime/mirror/class.h
@@ -1043,6 +1043,11 @@
DISALLOW_COPY_AND_ASSIGN(InitializeClassVisitor);
};
+ // Returns true if the class loader is null, ie the class loader is the boot strap class loader.
+ bool IsBootStrapClassLoaded() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ return GetClassLoader() == nullptr;
+ }
+
private:
void SetVerifyErrorClass(Class* klass) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);