mobile/bind: replace seq serialization with direct calls

The seq serialization machinery is a historic artifact from when Go mobile code had to run in a separate process. Now that Go code is running in-process, replace the explicit serialization with direct calls and pass arguments on the stack. The benefits are a much smaller bind runtime, much less garbage (and, in Java, fewer objects with finalizers), less argument copying, and faster cross-language calls. The cost is a more complex generator, because some of the work from the bind runtime is moved to generated code. Generated code now handles conversion between Go and Java/ObjC types, multiple return values and memory management of byte slice and string arguments. To overcome the lack of calling C code between Go packages, all bound packages now end up in the same (fake) package, "gomobile_bind", instead of separate packages (go_<pkgname>). To avoid name clashes, the package name is added as a prefix to generated functions and types. Also, don't copy byte arrays passed to Go, saving call time and allowing read([]byte)-style interfaces to foreign callers (#12113). Finally, add support for nil interfaces and struct pointers to objc. This is a large CL, but most of the changes stem from changing testdata. The full benchcmp output on the CL/20095 benchmarks on my Nexus 5 is reproduced below. Note that the savings for the JavaSlice* benchmarks are skewed because byte slices are no longer copied before passing them to Go. benchmark old ns/op new ns/op delta BenchmarkJavaEmpty 26.0 19.0 -26.92% BenchmarkJavaEmptyDirect 23.0 22.0 -4.35% BenchmarkJavaNoargs 7685 2339 -69.56% BenchmarkJavaNoargsDirect 17405 8041 -53.80% BenchmarkJavaOnearg 26887 2366 -91.20% BenchmarkJavaOneargDirect 34266 7910 -76.92% BenchmarkJavaOneret 38325 2245 -94.14% BenchmarkJavaOneretDirect 46265 7708 -83.34% BenchmarkJavaManyargs 41720 2535 -93.92% BenchmarkJavaManyargsDirect 51026 8373 -83.59% BenchmarkJavaRefjava 38139 21260 -44.26% BenchmarkJavaRefjavaDirect 42706 28150 -34.08% BenchmarkJavaRefgo 34403 6843 -80.11% BenchmarkJavaRefgoDirect 40193 16582 -58.74% BenchmarkJavaStringShort 32366 9323 -71.20% BenchmarkJavaStringShortDirect 41973 19118 -54.45% BenchmarkJavaStringLong 127879 94420 -26.16% BenchmarkJavaStringLongDirect 133776 114760 -14.21% BenchmarkJavaStringShortUnicode 32562 9221 -71.68% BenchmarkJavaStringShortUnicodeDirect 41464 19094 -53.95% BenchmarkJavaStringLongUnicode 131015 89401 -31.76% BenchmarkJavaStringLongUnicodeDirect 134130 90786 -32.31% BenchmarkJavaSliceShort 42462 7538 -82.25% BenchmarkJavaSliceShortDirect 52940 17017 -67.86% BenchmarkJavaSliceLong 138391 8466 -93.88% BenchmarkJavaSliceLongDirect 205804 15666 -92.39% BenchmarkGoEmpty 3.00 3.00 +0.00% BenchmarkGoEmptyDirect 3.00 3.00 +0.00% BenchmarkGoNoarg 40342 13716 -66.00% BenchmarkGoNoargDirect 46691 13569 -70.94% BenchmarkGoOnearg 43529 13757 -68.40% BenchmarkGoOneargDirect 44867 14078 -68.62% BenchmarkGoOneret 45456 13559 -70.17% BenchmarkGoOneretDirect 44694 13442 -69.92% BenchmarkGoRefjava 55111 28071 -49.06% BenchmarkGoRefjavaDirect 60883 26872 -55.86% BenchmarkGoRefgo 57038 29223 -48.77% BenchmarkGoRefgoDirect 56153 27812 -50.47% BenchmarkGoManyargs 67967 17398 -74.40% BenchmarkGoManyargsDirect 60617 16998 -71.96% BenchmarkGoStringShort 57538 22600 -60.72% BenchmarkGoStringShortDirect 52627 22704 -56.86% BenchmarkGoStringLong 128485 52530 -59.12% BenchmarkGoStringLongDirect 138377 52079 -62.36% BenchmarkGoStringShortUnicode 57062 22994 -59.70% BenchmarkGoStringShortUnicodeDirect 62563 22938 -63.34% BenchmarkGoStringLongUnicode 139913 55553 -60.29% BenchmarkGoStringLongUnicodeDirect 150863 57791 -61.69% BenchmarkGoSliceShort 59279 20215 -65.90% BenchmarkGoSliceShortDirect 60160 21136 -64.87% BenchmarkGoSliceLong 411225 301870 -26.59% BenchmarkGoSliceLongDirect 399029 298915 -25.09% Fixes golang/go#12619 Fixes golang/go#12113 Fixes golang/go#13033 Change-Id: I2b45e9e98a1248e3c23a5137f775f7364908bec7 Reviewed-on: https://go-review.googlesource.com/19821 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2026-05-22 18:43:29 -07:00 · 2016-03-03 15:03:45 +00:00
parent 988d17d203
commit 6fca37c69e
100 changed files with 6574 additions and 6307 deletions
@@ -0,0 +1,262 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// C support functions for bindings. This file is copied into the
+// generated gomobile_bind package and compiled along with the
+// generated binding files.
+
+#include <android/log.h>
+#include <errno.h>
+#include <jni.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <pthread.h>
+#include "seq.h"
+#include "_cgo_export.h"
+
+#define NULL_REFNUM 41
+
+static JavaVM *jvm;
+// jnienvs holds the per-thread JNIEnv* for Go threads where we called AttachCurrentThread.
+// A pthread key destructor is supplied to call DetachCurrentThread on exit. This trick is
+// documented in http://developer.android.com/training/articles/perf-jni.html under "Threads".
+static pthread_key_t jnienvs;
+
+static jclass seq_class;
+static jmethodID seq_throw_exc;
+static jmethodID seq_getRef;
+static jmethodID seq_decRef;
+static jmethodID seq_incRef;
+
+static jmethodID throwable_getMessage;
+
+static jfieldID ref_objField;
+
+// env_destructor is registered as a thread data key destructor to
+// clean up a Go thread that is attached to the JVM.
+static void env_destructor(void *env) {
+	if ((*jvm)->DetachCurrentThread(jvm) != JNI_OK) {
+		LOG_INFO("failed to detach current thread");
+	}
+}
+
+static JNIEnv *go_seq_get_thread_env(void) {
+	JNIEnv *env;
+	jint ret = (*jvm)->GetEnv(jvm, (void **)&env, JNI_VERSION_1_6);
+	if (ret != JNI_OK) {
+		if (ret != JNI_EDETACHED) {
+			LOG_FATAL("failed to get thread env");
+			return;
+		}
+		if ((*jvm)->AttachCurrentThread(jvm, &env, NULL) != JNI_OK) {
+			LOG_FATAL("failed to attach current thread");
+			return;
+		}
+		pthread_setspecific(jnienvs, env);
+	}
+	return env;
+}
+
+void go_seq_maybe_throw_exception(JNIEnv *env, jobject msg) {
+	if (msg != NULL && (*env)->GetStringLength(env, msg) > 0) {
+		(*env)->CallStaticVoidMethod(env, seq_class, seq_throw_exc, msg);
+	}
+}
+
+jstring go_seq_get_exception_message(JNIEnv *env) {
+	jthrowable exc = (*env)->ExceptionOccurred(env);
+	if (!exc) {
+		return NULL;
+	}
+	(*env)->ExceptionClear(env);
+	return (*env)->CallObjectMethod(env, exc, throwable_getMessage);
+}
+
+jbyteArray go_seq_to_java_bytearray(JNIEnv *env, nbyteslice s, int copy) {
+	if (s.ptr == NULL) {
+		return NULL;
+	}
+	jbyteArray res = (*env)->NewByteArray(env, s.len);
+	if (res == NULL) {
+		LOG_FATAL("NewByteArray failed");
+		return res;
+	}
+	(*env)->SetByteArrayRegion(env, res, 0, s.len, s.ptr);
+	if (copy) {
+		free(s.ptr);
+	}
+	return res;
+}
+
+nstring go_seq_from_java_string(JNIEnv *env, jstring str, int copy) {
+	struct nstring res = {NULL, 0};
+	if (str == NULL) {
+		return res;
+	}
+	jsize nchars = (*env)->GetStringLength(env, str);
+	jchar *chars = (jchar *)(*env)->GetStringChars(env, str, NULL);
+	if (chars == NULL) {
+		LOG_FATAL("GetStringChars failed");
+		return res;
+	}
+	if (copy) {
+		void *arr_copy = malloc(nchars*2);
+		if (arr_copy == NULL) {
+			LOG_FATAL("malloc failed");
+			return res;
+		}
+		memcpy(arr_copy, chars, nchars*2);
+		(*env)->ReleaseStringChars(env, str, chars);
+		chars = (jchar *)arr_copy;
+	}
+	res.chars = chars;
+	res.len = nchars;
+	return res;
+}
+
+nbyteslice go_seq_from_java_bytearray(JNIEnv *env, jbyteArray arr, int copy) {
+	struct nbyteslice res = {NULL, 0};
+	if (arr == NULL) {
+		return res;
+	}
+
+	jsize len = (*env)->GetArrayLength(env, arr);
+	if (len == 0) {
+		return res;
+	}
+	jbyte *ptr = (*env)->GetByteArrayElements(env, arr, NULL);
+	if (ptr == NULL) {
+		LOG_FATAL("GetByteArrayElements failed");
+		return res;
+	}
+	if (copy) {
+		void *ptr_copy = (void *)malloc(len);
+		if (ptr_copy == NULL) {
+			LOG_FATAL("malloc failed");
+			return res;
+		}
+		memcpy(ptr_copy, ptr, len);
+		(*env)->ReleaseByteArrayElements(env, arr, ptr, JNI_ABORT);
+		ptr = (jbyte *)ptr_copy;
+	}
+	res.ptr = ptr;
+	res.len = len;
+	return res;
+}
+
+int32_t go_seq_to_refnum(JNIEnv *env, jobject o) {
+	if (o == NULL) {
+		return NULL_REFNUM;
+	}
+	return (int32_t)(*env)->CallStaticIntMethod(env, seq_class, seq_incRef, o);
+}
+
+jobject go_seq_from_refnum(JNIEnv *env, int32_t refnum, jclass proxy_class, jmethodID proxy_cons) {
+	if (refnum == NULL_REFNUM) {
+		return NULL;
+	}
+	// Seq.Ref ref = Seq.getRef(refnum)
+	jobject ref = (*env)->CallStaticObjectMethod(env, seq_class, seq_getRef, (jint)refnum);
+	if (ref == NULL) {
+		LOG_FATAL("Unknown reference: %d", refnum);
+		return NULL;
+	}
+	if (refnum > 0) { // Java object
+		// return ref.obj
+		return (*env)->GetObjectField(env, ref, ref_objField);
+	} else {
+		// return new <Proxy>(ref)
+		return (*env)->NewObject(env, proxy_class, proxy_cons, ref);
+	}
+}
+
+// go_seq_to_java_string converts a nstring to a jstring.
+jstring go_seq_to_java_string(JNIEnv *env, nstring str) {
+	jstring s = (*env)->NewString(env, str.chars, str.len);
+	if (str.chars != NULL) {
+		free(str.chars);
+	}
+	return s;
+}
+
+// go_seq_push_local_frame retrieves or creates the JNIEnv* for the current thread
+// and pushes a JNI reference frame. Must be matched with call to go_seq_pop_local_frame.
+JNIEnv *go_seq_push_local_frame(jint cap) {
+	JNIEnv *env = go_seq_get_thread_env();
+	if ((*env)->PushLocalFrame(env, cap) < 0) {
+		LOG_FATAL("PushLocalFrame failed");
+	}
+	return env;
+}
+
+// Pop the current local frame, freeing all JNI local references in it
+void go_seq_pop_local_frame(JNIEnv *env) {
+	(*env)->PopLocalFrame(env, NULL);
+}
+
+void go_seq_dec_ref(int32_t ref) {
+	JNIEnv *env = go_seq_get_thread_env();
+	(*env)->CallStaticVoidMethod(env, seq_class, seq_decRef, (jint)ref);
+}
+
+JNIEXPORT void JNICALL
+Java_go_Seq_init(JNIEnv *env, jclass clazz) {
+	if ((*env)->GetJavaVM(env, &jvm) != 0) {
+		LOG_FATAL("failed to get JVM");
+		return;
+	}
+	if (pthread_key_create(&jnienvs, env_destructor) != 0) {
+		LOG_FATAL("failed to initialize jnienvs thread local storage");
+		return;
+	}
+
+	seq_class = (*env)->NewGlobalRef(env, clazz);
+	seq_throw_exc = (*env)->GetStaticMethodID(env, seq_class, "throwException", "(Ljava/lang/String;)V");
+	if (seq_throw_exc == NULL) {
+		LOG_FATAL("failed to find method Seq.throwException");
+		return;
+	}
+
+	seq_getRef = (*env)->GetStaticMethodID(env, seq_class, "getRef", "(I)Lgo/Seq$Ref;");
+	if (seq_getRef == NULL) {
+		LOG_FATAL("failed to find method Seq.getRef");
+		return;
+	}
+	seq_decRef = (*env)->GetStaticMethodID(env, seq_class, "decRef", "(I)V");
+	if (seq_decRef == NULL) {
+		LOG_FATAL("failed to find method Seq.decRef");
+		return;
+	}
+	seq_incRef = (*env)->GetStaticMethodID(env, seq_class, "incRef", "(Lgo/Seq$Object;)I");
+	if (seq_incRef == NULL) {
+		LOG_FATAL("failed to find method Seq.incRef");
+		return;
+	}
+	jclass throwable_class = (*env)->FindClass(env, "java/lang/Throwable");
+	if (throwable_class == NULL) {
+		LOG_FATAL("failed to find Throwable class");
+		return;
+	}
+	throwable_getMessage = (*env)->GetMethodID(env, throwable_class, "getMessage", "()Ljava/lang/String;");
+	if (throwable_getMessage == NULL) {
+		LOG_FATAL("failed to find method Throwable.getMessage");
+		return;
+	}
+	jclass ref_class = (*env)->FindClass(env, "go/Seq$Ref");
+	if (ref_class == NULL) {
+		LOG_FATAL("failed to find the Seq.Ref class");
+		return;
+	}
+	ref_objField = (*env)->GetFieldID(env, ref_class, "obj", "Lgo/Seq$Object;");
+	if (ref_objField == NULL) {
+		LOG_FATAL("failed to find the Seq.Ref.obj field");
+		return;
+	}
+}
+
+JNIEXPORT void JNICALL
+Java_go_Seq_destroyRef(JNIEnv *env, jclass clazz, jint refnum) {
+	DestroyRef(refnum);
+}