test/906-iterate-heap/iterate_heap.cc - LeafOS-Project/android_art - Gitiles

 /*
  * Copyright (C) 2013 The Android Open Source Project
  *
  * 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.
  */

 #include "inttypes.h"

 #include <iomanip>
 #include <iostream>
 #include <pthread.h>
 #include <sstream>
 #include <stdio.h>
 #include <vector>

 #include "android-base/stringprintf.h"
 #include "base/logging.h"
 #include "jni.h"
 #include "jvmti.h"
 #include "ScopedPrimitiveArray.h"
 #include "ti-agent/common_helper.h"
 #include "ti-agent/common_load.h"
 #include "utf.h"

 namespace art {
 namespace Test906IterateHeap {

 class IterationConfig {
  public:
   IterationConfig() {}
   virtual ~IterationConfig() {}

   virtual jint Handle(jlong class_tag, jlong size, jlong* tag_ptr, jint length) = 0;
 };

 static jint JNICALL HeapIterationCallback(jlong class_tag,
                                           jlong size,
                                           jlong* tag_ptr,
                                           jint length,
                                           void* user_data) {
   IterationConfig* config = reinterpret_cast<IterationConfig*>(user_data);
   return config->Handle(class_tag, size, tag_ptr, length);
 }

 static bool Run(jint heap_filter, jclass klass_filter, IterationConfig* config) {
   jvmtiHeapCallbacks callbacks;
   memset(&callbacks, 0, sizeof(jvmtiHeapCallbacks));
   callbacks.heap_iteration_callback = HeapIterationCallback;

   jvmtiError ret = jvmti_env->IterateThroughHeap(heap_filter,
                                                  klass_filter,
                                                  &callbacks,
                                                  config);
   if (ret != JVMTI_ERROR_NONE) {
     char* err;
     jvmti_env->GetErrorName(ret, &err);
     printf("Failure running IterateThroughHeap: %s\n", err);
     jvmti_env->Deallocate(reinterpret_cast<unsigned char*>(err));
     return false;
   }
   return true;
 }

 extern "C" JNIEXPORT jint JNICALL Java_Main_iterateThroughHeapCount(JNIEnv* env ATTRIBUTE_UNUSED,
                                                                     jclass klass ATTRIBUTE_UNUSED,
                                                                     jint heap_filter,
                                                                     jclass klass_filter,
                                                                     jint stop_after) {
   class CountIterationConfig : public IterationConfig {
    public:
     CountIterationConfig(jint _counter, jint _stop_after)
         : counter(_counter),
           stop_after(_stop_after) {
     }

     jint Handle(jlong class_tag ATTRIBUTE_UNUSED,
                 jlong size ATTRIBUTE_UNUSED,
                 jlong* tag_ptr ATTRIBUTE_UNUSED,
                 jint length ATTRIBUTE_UNUSED) OVERRIDE {
       counter++;
       if (counter == stop_after) {
         return JVMTI_VISIT_ABORT;
       }
       return 0;
     }

     jint counter;
     const jint stop_after;
   };

   CountIterationConfig config(0, stop_after);
   Run(heap_filter, klass_filter, &config);

   if (config.counter > config.stop_after) {
     printf("Error: more objects visited than signaled.");
   }

   return config.counter;
 }


 extern "C" JNIEXPORT jint JNICALL Java_Main_iterateThroughHeapData(JNIEnv* env,
                                                                    jclass klass ATTRIBUTE_UNUSED,
                                                                    jint heap_filter,
                                                                    jclass klass_filter,
                                                                    jlongArray class_tags,
                                                                    jlongArray sizes,
                                                                    jlongArray tags,
                                                                    jintArray lengths) {
   class DataIterationConfig : public IterationConfig {
    public:
     jint Handle(jlong class_tag, jlong size, jlong* tag_ptr, jint length) OVERRIDE {
       class_tags_.push_back(class_tag);
       sizes_.push_back(size);
       tags_.push_back(*tag_ptr);
       lengths_.push_back(length);

       return 0;  // Continue.
     }

     std::vector<jlong> class_tags_;
     std::vector<jlong> sizes_;
     std::vector<jlong> tags_;
     std::vector<jint> lengths_;
   };

   DataIterationConfig config;
   if (!Run(heap_filter, klass_filter, &config)) {
     return -1;
   }

   ScopedLongArrayRW s_class_tags(env, class_tags);
   ScopedLongArrayRW s_sizes(env, sizes);
   ScopedLongArrayRW s_tags(env, tags);
   ScopedIntArrayRW s_lengths(env, lengths);

   for (size_t i = 0; i != config.class_tags_.size(); ++i) {
     s_class_tags[i] = config.class_tags_[i];
     s_sizes[i] = config.sizes_[i];
     s_tags[i] = config.tags_[i];
     s_lengths[i] = config.lengths_[i];
   }

   return static_cast<jint>(config.class_tags_.size());
 }

 extern "C" JNIEXPORT void JNICALL Java_Main_iterateThroughHeapAdd(JNIEnv* env ATTRIBUTE_UNUSED,
                                                                   jclass klass ATTRIBUTE_UNUSED,
                                                                   jint heap_filter,
                                                                   jclass klass_filter) {
   class AddIterationConfig : public IterationConfig {
    public:
     AddIterationConfig() {}

     jint Handle(jlong class_tag ATTRIBUTE_UNUSED,
                 jlong size ATTRIBUTE_UNUSED,
                 jlong* tag_ptr,
                 jint length ATTRIBUTE_UNUSED) OVERRIDE {
       jlong current_tag = *tag_ptr;
       if (current_tag != 0) {
         *tag_ptr = current_tag + 10;
       }
       return 0;
     }
   };

   AddIterationConfig config;
   Run(heap_filter, klass_filter, &config);
 }

 extern "C" JNIEXPORT jstring JNICALL Java_Main_iterateThroughHeapString(
     JNIEnv* env, jclass klass ATTRIBUTE_UNUSED, jlong tag) {
   struct FindStringCallbacks {
     explicit FindStringCallbacks(jlong t) : tag_to_find(t) {}

     static jint JNICALL HeapIterationCallback(jlong class_tag ATTRIBUTE_UNUSED,
                                               jlong size ATTRIBUTE_UNUSED,
                                               jlong* tag_ptr ATTRIBUTE_UNUSED,
                                               jint length ATTRIBUTE_UNUSED,
                                               void* user_data ATTRIBUTE_UNUSED) {
       return 0;
     }

     static jint JNICALL StringValueCallback(jlong class_tag,
                                             jlong size,
                                             jlong* tag_ptr,
                                             const jchar* value,
                                             jint value_length,
                                             void* user_data) {
       FindStringCallbacks* p = reinterpret_cast<FindStringCallbacks*>(user_data);
       if (*tag_ptr == p->tag_to_find) {
         size_t utf_byte_count = CountUtf8Bytes(value, value_length);
         std::unique_ptr<char[]> mod_utf(new char[utf_byte_count + 1]);
         memset(mod_utf.get(), 0, utf_byte_count + 1);
         ConvertUtf16ToModifiedUtf8(mod_utf.get(), utf_byte_count, value, value_length);
         if (!p->data.empty()) {
           p->data += "\n";
         }
         p->data += android::base::StringPrintf("%" PRId64 "@%" PRId64 " (%" PRId64 ", '%s')",
                                                *tag_ptr,
                                                class_tag,
                                                size,
                                                mod_utf.get());
         // Update the tag to test whether that works.
         *tag_ptr = *tag_ptr + 1;
       }
       return 0;
     }

     std::string data;
     const jlong tag_to_find;
   };

   jvmtiHeapCallbacks callbacks;
   memset(&callbacks, 0, sizeof(jvmtiHeapCallbacks));
   callbacks.heap_iteration_callback = FindStringCallbacks::HeapIterationCallback;
   callbacks.string_primitive_value_callback = FindStringCallbacks::StringValueCallback;

   FindStringCallbacks fsc(tag);
   jvmtiError ret = jvmti_env->IterateThroughHeap(0, nullptr, &callbacks, &fsc);
   if (JvmtiErrorToException(env, ret)) {
     return nullptr;
   }
   return env->NewStringUTF(fsc.data.c_str());
 }

 extern "C" JNIEXPORT jstring JNICALL Java_Main_iterateThroughHeapPrimitiveArray(
     JNIEnv* env, jclass klass ATTRIBUTE_UNUSED, jlong tag) {
   struct FindArrayCallbacks {
     explicit FindArrayCallbacks(jlong t) : tag_to_find(t) {}

     static jint JNICALL HeapIterationCallback(jlong class_tag ATTRIBUTE_UNUSED,
                                               jlong size ATTRIBUTE_UNUSED,
                                               jlong* tag_ptr ATTRIBUTE_UNUSED,
                                               jint length ATTRIBUTE_UNUSED,
                                               void* user_data ATTRIBUTE_UNUSED) {
       return 0;
     }

     static jint JNICALL ArrayValueCallback(jlong class_tag,
                                            jlong size,
                                            jlong* tag_ptr,
                                            jint element_count,
                                            jvmtiPrimitiveType element_type,
                                            const void* elements,
                                            void* user_data) {
       FindArrayCallbacks* p = reinterpret_cast<FindArrayCallbacks*>(user_data);
       if (*tag_ptr == p->tag_to_find) {
         std::ostringstream oss;
         oss << *tag_ptr
             << '@'
             << class_tag
             << " ("
             << size
             << ", "
             << element_count
             << "x"
             << static_cast<char>(element_type)
             << " '";
         size_t element_size;
         switch (element_type) {
           case JVMTI_PRIMITIVE_TYPE_BOOLEAN:
           case JVMTI_PRIMITIVE_TYPE_BYTE:
             element_size = 1;
             break;
           case JVMTI_PRIMITIVE_TYPE_CHAR:
           case JVMTI_PRIMITIVE_TYPE_SHORT:
             element_size = 2;
             break;
           case JVMTI_PRIMITIVE_TYPE_INT:
           case JVMTI_PRIMITIVE_TYPE_FLOAT:
             element_size = 4;
             break;
           case JVMTI_PRIMITIVE_TYPE_LONG:
           case JVMTI_PRIMITIVE_TYPE_DOUBLE:
             element_size = 8;
             break;
           default:
             LOG(FATAL) << "Unknown type " << static_cast<size_t>(element_type);
             UNREACHABLE();
         }
         const uint8_t* data = reinterpret_cast<const uint8_t*>(elements);
         for (size_t i = 0; i != element_size * element_count; ++i) {
           oss << android::base::StringPrintf("%02x", data[i]);
         }
         oss << "')";

         if (!p->data.empty()) {
           p->data += "\n";
         }
         p->data += oss.str();
         // Update the tag to test whether that works.
         *tag_ptr = *tag_ptr + 1;
       }
       return 0;
     }

     std::string data;
     const jlong tag_to_find;
   };

   jvmtiHeapCallbacks callbacks;
   memset(&callbacks, 0, sizeof(jvmtiHeapCallbacks));
   callbacks.heap_iteration_callback = FindArrayCallbacks::HeapIterationCallback;
   callbacks.array_primitive_value_callback = FindArrayCallbacks::ArrayValueCallback;

   FindArrayCallbacks fac(tag);
   jvmtiError ret = jvmti_env->IterateThroughHeap(0, nullptr, &callbacks, &fac);
   if (JvmtiErrorToException(env, ret)) {
     return nullptr;
   }
   return env->NewStringUTF(fac.data.c_str());
 }

 static constexpr const char* GetPrimitiveTypeName(jvmtiPrimitiveType type) {
   switch (type) {
     case JVMTI_PRIMITIVE_TYPE_BOOLEAN:
       return "boolean";
     case JVMTI_PRIMITIVE_TYPE_BYTE:
       return "byte";
     case JVMTI_PRIMITIVE_TYPE_CHAR:
       return "char";
     case JVMTI_PRIMITIVE_TYPE_SHORT:
       return "short";
     case JVMTI_PRIMITIVE_TYPE_INT:
       return "int";
     case JVMTI_PRIMITIVE_TYPE_FLOAT:
       return "float";
     case JVMTI_PRIMITIVE_TYPE_LONG:
       return "long";
     case JVMTI_PRIMITIVE_TYPE_DOUBLE:
       return "double";
   }
   LOG(FATAL) << "Unknown type " << static_cast<size_t>(type);
   UNREACHABLE();
 }

 extern "C" JNIEXPORT jstring JNICALL Java_Main_iterateThroughHeapPrimitiveFields(
     JNIEnv* env, jclass klass ATTRIBUTE_UNUSED, jlong tag) {
   struct FindFieldCallbacks {
     explicit FindFieldCallbacks(jlong t) : tag_to_find(t) {}

     static jint JNICALL HeapIterationCallback(jlong class_tag ATTRIBUTE_UNUSED,
                                               jlong size ATTRIBUTE_UNUSED,
                                               jlong* tag_ptr ATTRIBUTE_UNUSED,
                                               jint length ATTRIBUTE_UNUSED,
                                               void* user_data ATTRIBUTE_UNUSED) {
       return 0;
     }

     static jint JNICALL PrimitiveFieldValueCallback(jvmtiHeapReferenceKind kind,
                                                     const jvmtiHeapReferenceInfo* info,
                                                     jlong class_tag,
                                                     jlong* tag_ptr,
                                                     jvalue value,
                                                     jvmtiPrimitiveType value_type,
                                                     void* user_data) {
       FindFieldCallbacks* p = reinterpret_cast<FindFieldCallbacks*>(user_data);
       if (*tag_ptr >= p->tag_to_find) {
         std::ostringstream oss;
         oss << *tag_ptr
             << '@'
             << class_tag
             << " ("
             << (kind == JVMTI_HEAP_REFERENCE_FIELD ? "instance, " : "static, ")
             << GetPrimitiveTypeName(value_type)
             << ", index="
             << info->field.index
             << ") ";
         // Be lazy, always print eight bytes.
         static_assert(sizeof(jvalue) == sizeof(uint64_t), "Unexpected jvalue size");
         uint64_t val;
         memcpy(&val, &value, sizeof(uint64_t));  // To avoid undefined behavior.
         oss << android::base::StringPrintf("%016" PRIx64, val);

         if (!p->data.empty()) {
           p->data += "\n";
         }
         p->data += oss.str();
         *tag_ptr = *tag_ptr + 1;
       }
       return 0;
     }

     std::string data;
     const jlong tag_to_find;
   };

   jvmtiHeapCallbacks callbacks;
   memset(&callbacks, 0, sizeof(jvmtiHeapCallbacks));
   callbacks.heap_iteration_callback = FindFieldCallbacks::HeapIterationCallback;
   callbacks.primitive_field_callback = FindFieldCallbacks::PrimitiveFieldValueCallback;

   FindFieldCallbacks ffc(tag);
   jvmtiError ret = jvmti_env->IterateThroughHeap(0, nullptr, &callbacks, &ffc);
   if (JvmtiErrorToException(env, ret)) {
     return nullptr;
   }
   return env->NewStringUTF(ffc.data.c_str());
 }

 }  // namespace Test906IterateHeap
 }  // namespace art
	/*
	* Copyright (C) 2013 The Android Open Source Project
	*
	* 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.
	*/

	#include "inttypes.h"

	#include <iomanip>
	#include <iostream>
	#include <pthread.h>
	#include <sstream>
	#include <stdio.h>
	#include <vector>

	#include "android-base/stringprintf.h"
	#include "base/logging.h"
	#include "jni.h"
	#include "jvmti.h"
	#include "ScopedPrimitiveArray.h"
	#include "ti-agent/common_helper.h"
	#include "ti-agent/common_load.h"
	#include "utf.h"

	namespace art {
	namespace Test906IterateHeap {

	class IterationConfig {
	public:
	IterationConfig() {}
	virtual ~IterationConfig() {}

	virtual jint Handle(jlong class_tag, jlong size, jlong* tag_ptr, jint length) = 0;
	};

	static jint JNICALL HeapIterationCallback(jlong class_tag,
	jlong size,
	jlong* tag_ptr,
	jint length,
	void* user_data) {
	IterationConfig* config = reinterpret_cast<IterationConfig*>(user_data);
	return config->Handle(class_tag, size, tag_ptr, length);
	}

	static bool Run(jint heap_filter, jclass klass_filter, IterationConfig* config) {
	jvmtiHeapCallbacks callbacks;
	memset(&callbacks, 0, sizeof(jvmtiHeapCallbacks));
	callbacks.heap_iteration_callback = HeapIterationCallback;

	jvmtiError ret = jvmti_env->IterateThroughHeap(heap_filter,
	klass_filter,
	&callbacks,
	config);
	if (ret != JVMTI_ERROR_NONE) {
	char* err;
	jvmti_env->GetErrorName(ret, &err);
	printf("Failure running IterateThroughHeap: %s\n", err);
	jvmti_env->Deallocate(reinterpret_cast<unsigned char*>(err));
	return false;
	}
	return true;
	}

	extern "C" JNIEXPORT jint JNICALL Java_Main_iterateThroughHeapCount(JNIEnv* env ATTRIBUTE_UNUSED,
	jclass klass ATTRIBUTE_UNUSED,
	jint heap_filter,
	jclass klass_filter,
	jint stop_after) {
	class CountIterationConfig : public IterationConfig {
	public:
	CountIterationConfig(jint _counter, jint _stop_after)
	: counter(_counter),
	stop_after(_stop_after) {
	}

	jint Handle(jlong class_tag ATTRIBUTE_UNUSED,
	jlong size ATTRIBUTE_UNUSED,
	jlong* tag_ptr ATTRIBUTE_UNUSED,
	jint length ATTRIBUTE_UNUSED) OVERRIDE {
	counter++;
	if (counter == stop_after) {
	return JVMTI_VISIT_ABORT;
	}
	return 0;
	}

	jint counter;
	const jint stop_after;
	};

	CountIterationConfig config(0, stop_after);
	Run(heap_filter, klass_filter, &config);

	if (config.counter > config.stop_after) {
	printf("Error: more objects visited than signaled.");
	}

	return config.counter;
	}


	extern "C" JNIEXPORT jint JNICALL Java_Main_iterateThroughHeapData(JNIEnv* env,
	jclass klass ATTRIBUTE_UNUSED,
	jint heap_filter,
	jclass klass_filter,
	jlongArray class_tags,
	jlongArray sizes,
	jlongArray tags,
	jintArray lengths) {
	class DataIterationConfig : public IterationConfig {
	public:
	jint Handle(jlong class_tag, jlong size, jlong* tag_ptr, jint length) OVERRIDE {
	class_tags_.push_back(class_tag);
	sizes_.push_back(size);
	tags_.push_back(*tag_ptr);
	lengths_.push_back(length);

	return 0; // Continue.
	}

	std::vector<jlong> class_tags_;
	std::vector<jlong> sizes_;
	std::vector<jlong> tags_;
	std::vector<jint> lengths_;
	};

	DataIterationConfig config;
	if (!Run(heap_filter, klass_filter, &config)) {
	return -1;
	}

	ScopedLongArrayRW s_class_tags(env, class_tags);
	ScopedLongArrayRW s_sizes(env, sizes);
	ScopedLongArrayRW s_tags(env, tags);
	ScopedIntArrayRW s_lengths(env, lengths);

	for (size_t i = 0; i != config.class_tags_.size(); ++i) {
	s_class_tags[i] = config.class_tags_[i];
	s_sizes[i] = config.sizes_[i];
	s_tags[i] = config.tags_[i];
	s_lengths[i] = config.lengths_[i];
	}

	return static_cast<jint>(config.class_tags_.size());
	}

	extern "C" JNIEXPORT void JNICALL Java_Main_iterateThroughHeapAdd(JNIEnv* env ATTRIBUTE_UNUSED,
	jclass klass ATTRIBUTE_UNUSED,
	jint heap_filter,
	jclass klass_filter) {
	class AddIterationConfig : public IterationConfig {
	public:
	AddIterationConfig() {}

	jint Handle(jlong class_tag ATTRIBUTE_UNUSED,
	jlong size ATTRIBUTE_UNUSED,
	jlong* tag_ptr,
	jint length ATTRIBUTE_UNUSED) OVERRIDE {
	jlong current_tag = *tag_ptr;
	if (current_tag != 0) {
	*tag_ptr = current_tag + 10;
	}
	return 0;
	}
	};

	AddIterationConfig config;
	Run(heap_filter, klass_filter, &config);
	}

	extern "C" JNIEXPORT jstring JNICALL Java_Main_iterateThroughHeapString(
	JNIEnv* env, jclass klass ATTRIBUTE_UNUSED, jlong tag) {
	struct FindStringCallbacks {
	explicit FindStringCallbacks(jlong t) : tag_to_find(t) {}

	static jint JNICALL HeapIterationCallback(jlong class_tag ATTRIBUTE_UNUSED,
	jlong size ATTRIBUTE_UNUSED,
	jlong* tag_ptr ATTRIBUTE_UNUSED,
	jint length ATTRIBUTE_UNUSED,
	void* user_data ATTRIBUTE_UNUSED) {
	return 0;
	}

	static jint JNICALL StringValueCallback(jlong class_tag,
	jlong size,
	jlong* tag_ptr,
	const jchar* value,
	jint value_length,
	void* user_data) {
	FindStringCallbacks* p = reinterpret_cast<FindStringCallbacks*>(user_data);
	if (*tag_ptr == p->tag_to_find) {
	size_t utf_byte_count = CountUtf8Bytes(value, value_length);
	std::unique_ptr<char[]> mod_utf(new char[utf_byte_count + 1]);
	memset(mod_utf.get(), 0, utf_byte_count + 1);
	ConvertUtf16ToModifiedUtf8(mod_utf.get(), utf_byte_count, value, value_length);
	if (!p->data.empty()) {
	p->data += "\n";
	}
	p->data += android::base::StringPrintf("%" PRId64 "@%" PRId64 " (%" PRId64 ", '%s')",
	*tag_ptr,
	class_tag,
	size,
	mod_utf.get());
	// Update the tag to test whether that works.
	tag_ptr = tag_ptr + 1;
	}
	return 0;
	}

	std::string data;
	const jlong tag_to_find;
	};

	jvmtiHeapCallbacks callbacks;
	memset(&callbacks, 0, sizeof(jvmtiHeapCallbacks));
	callbacks.heap_iteration_callback = FindStringCallbacks::HeapIterationCallback;
	callbacks.string_primitive_value_callback = FindStringCallbacks::StringValueCallback;

	FindStringCallbacks fsc(tag);
	jvmtiError ret = jvmti_env->IterateThroughHeap(0, nullptr, &callbacks, &fsc);
	if (JvmtiErrorToException(env, ret)) {
	return nullptr;
	}
	return env->NewStringUTF(fsc.data.c_str());
	}

	extern "C" JNIEXPORT jstring JNICALL Java_Main_iterateThroughHeapPrimitiveArray(
	JNIEnv* env, jclass klass ATTRIBUTE_UNUSED, jlong tag) {
	struct FindArrayCallbacks {
	explicit FindArrayCallbacks(jlong t) : tag_to_find(t) {}

	static jint JNICALL HeapIterationCallback(jlong class_tag ATTRIBUTE_UNUSED,
	jlong size ATTRIBUTE_UNUSED,
	jlong* tag_ptr ATTRIBUTE_UNUSED,
	jint length ATTRIBUTE_UNUSED,
	void* user_data ATTRIBUTE_UNUSED) {
	return 0;
	}

	static jint JNICALL ArrayValueCallback(jlong class_tag,
	jlong size,
	jlong* tag_ptr,
	jint element_count,
	jvmtiPrimitiveType element_type,
	const void* elements,
	void* user_data) {
	FindArrayCallbacks* p = reinterpret_cast<FindArrayCallbacks*>(user_data);
	if (*tag_ptr == p->tag_to_find) {
	std::ostringstream oss;
	oss << *tag_ptr
	<< '@'
	<< class_tag
	<< " ("
	<< size
	<< ", "
	<< element_count
	<< "x"
	<< static_cast<char>(element_type)
	<< " '";
	size_t element_size;
	switch (element_type) {
	case JVMTI_PRIMITIVE_TYPE_BOOLEAN:
	case JVMTI_PRIMITIVE_TYPE_BYTE:
	element_size = 1;
	break;
	case JVMTI_PRIMITIVE_TYPE_CHAR:
	case JVMTI_PRIMITIVE_TYPE_SHORT:
	element_size = 2;
	break;
	case JVMTI_PRIMITIVE_TYPE_INT:
	case JVMTI_PRIMITIVE_TYPE_FLOAT:
	element_size = 4;
	break;
	case JVMTI_PRIMITIVE_TYPE_LONG:
	case JVMTI_PRIMITIVE_TYPE_DOUBLE:
	element_size = 8;
	break;
	default:
	LOG(FATAL) << "Unknown type " << static_cast<size_t>(element_type);
	UNREACHABLE();
	}
	const uint8_t* data = reinterpret_cast<const uint8_t*>(elements);
	for (size_t i = 0; i != element_size * element_count; ++i) {
	oss << android::base::StringPrintf("%02x", data[i]);
	}
	oss << "')";

	if (!p->data.empty()) {
	p->data += "\n";
	}
	p->data += oss.str();
	// Update the tag to test whether that works.
	tag_ptr = tag_ptr + 1;
	}
	return 0;
	}

	std::string data;
	const jlong tag_to_find;
	};

	jvmtiHeapCallbacks callbacks;
	memset(&callbacks, 0, sizeof(jvmtiHeapCallbacks));
	callbacks.heap_iteration_callback = FindArrayCallbacks::HeapIterationCallback;
	callbacks.array_primitive_value_callback = FindArrayCallbacks::ArrayValueCallback;

	FindArrayCallbacks fac(tag);
	jvmtiError ret = jvmti_env->IterateThroughHeap(0, nullptr, &callbacks, &fac);
	if (JvmtiErrorToException(env, ret)) {
	return nullptr;
	}
	return env->NewStringUTF(fac.data.c_str());
	}

	static constexpr const char* GetPrimitiveTypeName(jvmtiPrimitiveType type) {
	switch (type) {
	case JVMTI_PRIMITIVE_TYPE_BOOLEAN:
	return "boolean";
	case JVMTI_PRIMITIVE_TYPE_BYTE:
	return "byte";
	case JVMTI_PRIMITIVE_TYPE_CHAR:
	return "char";
	case JVMTI_PRIMITIVE_TYPE_SHORT:
	return "short";
	case JVMTI_PRIMITIVE_TYPE_INT:
	return "int";
	case JVMTI_PRIMITIVE_TYPE_FLOAT:
	return "float";
	case JVMTI_PRIMITIVE_TYPE_LONG:
	return "long";
	case JVMTI_PRIMITIVE_TYPE_DOUBLE:
	return "double";
	}
	LOG(FATAL) << "Unknown type " << static_cast<size_t>(type);
	UNREACHABLE();
	}

	extern "C" JNIEXPORT jstring JNICALL Java_Main_iterateThroughHeapPrimitiveFields(
	JNIEnv* env, jclass klass ATTRIBUTE_UNUSED, jlong tag) {
	struct FindFieldCallbacks {
	explicit FindFieldCallbacks(jlong t) : tag_to_find(t) {}

	static jint JNICALL HeapIterationCallback(jlong class_tag ATTRIBUTE_UNUSED,
	jlong size ATTRIBUTE_UNUSED,
	jlong* tag_ptr ATTRIBUTE_UNUSED,
	jint length ATTRIBUTE_UNUSED,
	void* user_data ATTRIBUTE_UNUSED) {
	return 0;
	}

	static jint JNICALL PrimitiveFieldValueCallback(jvmtiHeapReferenceKind kind,
	const jvmtiHeapReferenceInfo* info,
	jlong class_tag,
	jlong* tag_ptr,
	jvalue value,
	jvmtiPrimitiveType value_type,
	void* user_data) {
	FindFieldCallbacks* p = reinterpret_cast<FindFieldCallbacks*>(user_data);
	if (*tag_ptr >= p->tag_to_find) {
	std::ostringstream oss;
	oss << *tag_ptr
	<< '@'
	<< class_tag
	<< " ("
	<< (kind == JVMTI_HEAP_REFERENCE_FIELD ? "instance, " : "static, ")
	<< GetPrimitiveTypeName(value_type)
	<< ", index="
	<< info->field.index
	<< ") ";
	// Be lazy, always print eight bytes.
	static_assert(sizeof(jvalue) == sizeof(uint64_t), "Unexpected jvalue size");
	uint64_t val;
	memcpy(&val, &value, sizeof(uint64_t)); // To avoid undefined behavior.
	oss << android::base::StringPrintf("%016" PRIx64, val);

	if (!p->data.empty()) {
	p->data += "\n";
	}
	p->data += oss.str();
	tag_ptr = tag_ptr + 1;
	}
	return 0;
	}

	std::string data;
	const jlong tag_to_find;
	};

	jvmtiHeapCallbacks callbacks;
	memset(&callbacks, 0, sizeof(jvmtiHeapCallbacks));
	callbacks.heap_iteration_callback = FindFieldCallbacks::HeapIterationCallback;
	callbacks.primitive_field_callback = FindFieldCallbacks::PrimitiveFieldValueCallback;

	FindFieldCallbacks ffc(tag);
	jvmtiError ret = jvmti_env->IterateThroughHeap(0, nullptr, &callbacks, &ffc);
	if (JvmtiErrorToException(env, ret)) {
	return nullptr;
	}
	return env->NewStringUTF(ffc.data.c_str());
	}

	} // namespace Test906IterateHeap
	} // namespace art