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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_ANDROID_JNI_GENERATOR_JNI_GENERATOR_HELPER_H_
#define BASE_ANDROID_JNI_GENERATOR_JNI_GENERATOR_HELPER_H_
#include <jni.h>
#include "base/android/jni_android.h"
#include "base/android/jni_int_wrapper.h"
#include "base/android/scoped_java_ref.h"
#include "base/base_export.h"
#include "base/compiler_specific.h"
#include "base/logging.h"
#include "base/memory/raw_ptr.h"
#include "build/build_config.h"
// Project-specific macros used by the header files generated by
// jni_generator.py. Different projects can then specify their own
// implementation for this file.
#define CHECK_NATIVE_PTR(env, jcaller, native_ptr, method_name, ...) \
DCHECK(native_ptr) << method_name;
#define CHECK_CLAZZ(env, jcaller, clazz, ...) DCHECK(clazz);
#if defined(ARCH_CPU_X86)
// Dalvik JIT generated code doesn't guarantee 16-byte stack alignment on
// x86 - use force_align_arg_pointer to realign the stack at the JNI
// boundary. crbug.com/655248
#define JNI_GENERATOR_EXPORT \
extern "C" __attribute__((visibility("default"), force_align_arg_pointer))
#else
#define JNI_GENERATOR_EXPORT extern "C" __attribute__((visibility("default")))
#endif
// Used to export JNI registration functions.
#if defined(COMPONENT_BUILD)
#define JNI_REGISTRATION_EXPORT __attribute__((visibility("default")))
#else
#define JNI_REGISTRATION_EXPORT
#endif
namespace jni_generator {
inline void HandleRegistrationError(JNIEnv* env,
jclass clazz,
const char* filename) {
LOG(ERROR) << "RegisterNatives failed in " << filename;
}
inline void CheckException(JNIEnv* env) {
base::android::CheckException(env);
}
// A 32 bit number could be an address on stack. Random 64 bit marker on the
// stack is much less likely to be present on stack.
constexpr uint64_t kJniStackMarkerValue = 0xbdbdef1bebcade1b;
// Context about the JNI call with exception checked to be stored in stack.
struct BASE_EXPORT JniJavaCallContextUnchecked {
ALWAYS_INLINE JniJavaCallContextUnchecked() {
// TODO(ssid): Implement for other architectures.
#if defined(__arm__) || defined(__aarch64__)
// This assumes that this method does not increment the stack pointer.
asm volatile("mov %0, sp" : "=r"(sp));
#else
sp = 0;
#endif
}
// Force no inline to reduce code size.
template <base::android::MethodID::Type type>
NOINLINE void Init(JNIEnv* env,
jclass clazz,
const char* method_name,
const char* jni_signature,
std::atomic<jmethodID>* atomic_method_id) {
env1 = env;
// Make sure compiler doesn't optimize out the assignment.
memcpy(&marker, &kJniStackMarkerValue, sizeof(kJniStackMarkerValue));
// Gets PC of the calling function.
pc = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
method_id = base::android::MethodID::LazyGet<type>(
env, clazz, method_name, jni_signature, atomic_method_id);
}
NOINLINE ~JniJavaCallContextUnchecked() {
// Reset so that spurious marker finds are avoided.
memset(&marker, 0, sizeof(marker));
}
uint64_t marker;
uintptr_t sp;
uintptr_t pc;
raw_ptr<JNIEnv> env1;
jmethodID method_id;
};
// Context about the JNI call with exception unchecked to be stored in stack.
struct BASE_EXPORT JniJavaCallContextChecked {
// Force no inline to reduce code size.
template <base::android::MethodID::Type type>
NOINLINE void Init(JNIEnv* env,
jclass clazz,
const char* method_name,
const char* jni_signature,
std::atomic<jmethodID>* atomic_method_id) {
base.Init<type>(env, clazz, method_name, jni_signature, atomic_method_id);
// Reset |pc| to correct caller.
base.pc = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
}
NOINLINE ~JniJavaCallContextChecked() {
jni_generator::CheckException(base.env1);
}
JniJavaCallContextUnchecked base;
};
static_assert(sizeof(JniJavaCallContextChecked) ==
sizeof(JniJavaCallContextUnchecked),
"Stack unwinder cannot work with structs of different sizes.");
} // namespace jni_generator
#endif // BASE_ANDROID_JNI_GENERATOR_JNI_GENERATOR_HELPER_H_