/*
 * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.tools.jaotc.binformat;

import static org.graalvm.compiler.hotspot.meta.HotSpotAOTProfilingPlugin.Options.TieredAOT;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import jdk.tools.jaotc.binformat.Symbol.Binding;
import jdk.tools.jaotc.binformat.Symbol.Kind;
import jdk.tools.jaotc.binformat.elf.JELFRelocObject;
import jdk.tools.jaotc.binformat.macho.JMachORelocObject;
import jdk.tools.jaotc.binformat.pecoff.JPECoffRelocObject;
import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration;
import org.graalvm.compiler.options.OptionValues;

A format-agnostic container class that holds various components of a binary.

This class holds information necessary to create platform-specific binary containers such as
ELFContainer for Linux and Solaris operating systems or MachOContainer for Mac OS or PEContainer
for MS Windows operating systems.

Method APIs provided by this class are used to construct and populate platform-independent
contents of a binary as the first step to create a binary representation of code generated by a
compiler backend such as Graal.

Methods to record and access code section contents, symbols and relocations are provided.
/**
 * A format-agnostic container class that holds various components of a binary.
 *
 * <p>
 * This class holds information necessary to create platform-specific binary containers such as
 * ELFContainer for Linux and Solaris operating systems or MachOContainer for Mac OS or PEContainer
 * for MS Windows operating systems.
 *
 * <p>
 * Method APIs provided by this class are used to construct and populate platform-independent
 * contents of a binary as the first step to create a binary representation of code generated by a
 * compiler backend such as Graal.
 *
 * <p>
 * Methods to record and access code section contents, symbols and relocations are provided.
 */
public final class BinaryContainer implements SymbolTable {
    private final OptionValues graalOptions;

    private final int codeSegmentSize;

    private final int codeEntryAlignment;

    private final boolean threadLocalHandshakes;

    
Container holding code bits and any other related information.
/**
     * Container holding code bits and any other related information.
     */
    private final CodeContainer codeContainer;

    
Container holding global offset data for hotspot linkage.
/**
     * Container holding global offset data for hotspot linkage.
     */
    private final ByteContainer extLinkageGOTContainer;

    
Patched by HotSpot, contains Klass pointers.
/**
     * Patched by HotSpot, contains Klass pointers.
     */
    private final ByteContainer klassesGotContainer;

    
Patched by HotSpot, contains MethodCounters pointers.
/**
     * Patched by HotSpot, contains MethodCounters pointers.
     */
    private final ByteContainer countersGotContainer;

    
Patched lazily by hotspot, contains klass/method pointers.
/**
     * Patched lazily by hotspot, contains klass/method pointers.
     */
    private final ByteContainer metadataGotContainer;

    
BSS container, contains method state array.
/**
     * BSS container, contains method state array.
     */
    private final ByteContainer methodStateContainer;

    
Patched by hotspot, contains java object pointers.
/**
     * Patched by hotspot, contains java object pointers.
     */
    private final ByteContainer oopGotContainer;

    // Containers holding read-only data
    private final ReadOnlyDataContainer configContainer;
    private final ReadOnlyDataContainer metaspaceNamesContainer;
    private final ReadOnlyDataContainer methodsOffsetsContainer;
    private final ReadOnlyDataContainer klassesOffsetsContainer;
    private final ReadOnlyDataContainer klassesDependenciesContainer;
    private final HeaderContainer headerContainer;
    private final ReadOnlyDataContainer stubsOffsetsContainer;
    private final ReadOnlyDataContainer codeSegmentsContainer;

    // This cannot be read only since we need to patch the metadata at runtime..
    private final ReadOnlyDataContainer methodMetadataContainer;

    
Container containing constant data used by code.
/**
     * Container containing constant data used by code.
     */
    private final ReadOnlyDataContainer constantDataContainer;

    
Map holding the Strings table.
/**
     * Map holding the Strings table.
     */
    private final Map<String, Integer> offsetStringTable = new HashMap<>();

    private final Map<String, Integer> metaspaceNames = new HashMap<>();

    // List of relocation table entries - (symbolName, relocationInfo)
    private final Map<String, Symbol> symbolTable = new HashMap<>();
    private final Map<Symbol, List<Relocation>> relocationTable = new HashMap<>();
    private final Map<Symbol, Relocation> uniqueRelocationTable = new HashMap<>();

    
Mapping of local VM function names to known global symbols generated in the output binary.
/**
     * Mapping of local VM function names to known global symbols generated in the output binary.
     */
    private static final HashMap<String, String> functionNamesToAOTSymbols = new HashMap<>();

    private static final String[][] map = {
//@formatter:off
        {"CompilerToVM::Data::SharedRuntime_deopt_blob_unpack",        "_aot_deopt_blob_unpack"},
        {"CompilerToVM::Data::SharedRuntime_deopt_blob_uncommon_trap", "_aot_deopt_blob_uncommon_trap"},
        {"CompilerToVM::Data::SharedRuntime_ic_miss_stub",             "_aot_ic_miss_stub"},
        {"CompilerToVM::Data::SharedRuntime_handle_wrong_method_stub", "_aot_handle_wrong_method_stub"},
        {"SharedRuntime::exception_handler_for_return_address",        "_aot_exception_handler_for_return_address"},
        {"SharedRuntime::register_finalizer",                          "_aot_register_finalizer"},
        {"SharedRuntime::OSR_migration_end",                           "_aot_OSR_migration_end"},
        {"CompilerRuntime::resolve_dynamic_invoke",                    "_aot_resolve_dynamic_invoke"},
        {"CompilerRuntime::resolve_string_by_symbol",                  "_aot_resolve_string_by_symbol"},
        {"CompilerRuntime::resolve_klass_by_symbol",                   "_aot_resolve_klass_by_symbol"},
        {"CompilerRuntime::resolve_method_by_symbol_and_load_counters","_aot_resolve_method_by_symbol_and_load_counters"},
        {"CompilerRuntime::initialize_klass_by_symbol",                "_aot_initialize_klass_by_symbol"},
        {"CompilerRuntime::invocation_event",                          "_aot_invocation_event"},
        {"CompilerRuntime::backedge_event",                            "_aot_backedge_event"},

        {"CompilerToVM::Data::dpow", "_aot_shared_runtime_dpow"},
        {"CompilerToVM::Data::dexp", "_aot_shared_runtime_dexp"},
        {"CompilerToVM::Data::dcos", "_aot_shared_runtime_dcos"},
        {"CompilerToVM::Data::dsin", "_aot_shared_runtime_dsin"},
        {"CompilerToVM::Data::dtan", "_aot_shared_runtime_dtan"},
        {"CompilerToVM::Data::dlog", "_aot_shared_runtime_dlog"},
        {"CompilerToVM::Data::dlog10", "_aot_shared_runtime_dlog10"},

        {"StubRoutines::_jbyte_arraycopy", "_aot_stub_routines_jbyte_arraycopy"},
        {"StubRoutines::_jshort_arraycopy", "_aot_stub_routines_jshort_arraycopy"},
        {"StubRoutines::_jint_arraycopy", "_aot_stub_routines_jint_arraycopy"},
        {"StubRoutines::_jlong_arraycopy", "_aot_stub_routines_jlong_arraycopy"},
        {"StubRoutines::_oop_arraycopy", "_aot_stub_routines_oop_arraycopy"},
        {"StubRoutines::_oop_arraycopy_uninit", "_aot_stub_routines_oop_arraycopy_uninit"},

        {"StubRoutines::_jbyte_disjoint_arraycopy", "_aot_stub_routines_jbyte_disjoint_arraycopy"},
        {"StubRoutines::_jshort_disjoint_arraycopy", "_aot_stub_routines_jshort_disjoint_arraycopy"},
        {"StubRoutines::_jint_disjoint_arraycopy", "_aot_stub_routines_jint_disjoint_arraycopy"},
        {"StubRoutines::_jlong_disjoint_arraycopy", "_aot_stub_routines_jlong_disjoint_arraycopy"},
        {"StubRoutines::_oop_disjoint_arraycopy", "_aot_stub_routines_oop_disjoint_arraycopy"},
        {"StubRoutines::_oop_disjoint_arraycopy_uninit", "_aot_stub_routines_oop_disjoint_arraycopy_uninit"},

        {"StubRoutines::_arrayof_jbyte_arraycopy", "_aot_stub_routines_arrayof_jbyte_arraycopy"},
        {"StubRoutines::_arrayof_jshort_arraycopy", "_aot_stub_routines_arrayof_jshort_arraycopy"},
        {"StubRoutines::_arrayof_jint_arraycopy", "_aot_stub_routines_arrayof_jint_arraycopy"},
        {"StubRoutines::_arrayof_jlong_arraycopy", "_aot_stub_routines_arrayof_jlong_arraycopy"},
        {"StubRoutines::_arrayof_oop_arraycopy", "_aot_stub_routines_arrayof_oop_arraycopy"},
        {"StubRoutines::_arrayof_oop_arraycopy_uninit", "_aot_stub_routines_arrayof_oop_arraycopy_uninit"},

        {"StubRoutines::_arrayof_jbyte_disjoint_arraycopy", "_aot_stub_routines_arrayof_jbyte_disjoint_arraycopy"},
        {"StubRoutines::_arrayof_jshort_disjoint_arraycopy", "_aot_stub_routines_arrayof_jshort_disjoint_arraycopy"},
        {"StubRoutines::_arrayof_jint_disjoint_arraycopy", "_aot_stub_routines_arrayof_jint_disjoint_arraycopy"},
        {"StubRoutines::_arrayof_jlong_disjoint_arraycopy", "_aot_stub_routines_arrayof_jlong_disjoint_arraycopy"},
        {"StubRoutines::_arrayof_oop_disjoint_arraycopy", "_aot_stub_routines_arrayof_oop_disjoint_arraycopy"},
        {"StubRoutines::_arrayof_oop_disjoint_arraycopy_uninit", "_aot_stub_routines_arrayof_oop_disjoint_arraycopy_uninit"},

        {"StubRoutines::_unsafe_arraycopy", "_aot_stub_routines_unsafe_arraycopy"},

        {"StubRoutines::_checkcast_arraycopy", "_aot_stub_routines_checkcast_arraycopy"},

        {"StubRoutines::_generic_arraycopy", "_aot_stub_routines_generic_arraycopy"},

        {"StubRoutines::_aescrypt_encryptBlock", "_aot_stub_routines_aescrypt_encryptBlock"},
        {"StubRoutines::_aescrypt_decryptBlock", "_aot_stub_routines_aescrypt_decryptBlock"},
        {"StubRoutines::_cipherBlockChaining_encryptAESCrypt", "_aot_stub_routines_cipherBlockChaining_encryptAESCrypt"},
        {"StubRoutines::_cipherBlockChaining_decryptAESCrypt", "_aot_stub_routines_cipherBlockChaining_decryptAESCrypt"},
        {"StubRoutines::_updateBytesCRC32", "_aot_stub_routines_update_bytes_crc32"},
        {"StubRoutines::_crc_table_adr", "_aot_stub_routines_crc_table_adr"},

        {"StubRoutines::_sha1_implCompress", "_aot_stub_routines_sha1_implCompress" },
        {"StubRoutines::_sha1_implCompressMB", "_aot_stub_routines_sha1_implCompressMB" },
        {"StubRoutines::_sha256_implCompress", "_aot_stub_routines_sha256_implCompress" },
        {"StubRoutines::_sha256_implCompressMB", "_aot_stub_routines_sha256_implCompressMB" },
        {"StubRoutines::_sha512_implCompress", "_aot_stub_routines_sha512_implCompress" },
        {"StubRoutines::_sha512_implCompressMB", "_aot_stub_routines_sha512_implCompressMB" },
        {"StubRoutines::_multiplyToLen", "_aot_stub_routines_multiplyToLen" },

        {"StubRoutines::_counterMode_AESCrypt", "_aot_stub_routines_counterMode_AESCrypt" },
        {"StubRoutines::_ghash_processBlocks", "_aot_stub_routines_ghash_processBlocks" },
        {"StubRoutines::_crc32c_table_addr", "_aot_stub_routines_crc32c_table_addr" },
        {"StubRoutines::_updateBytesCRC32C", "_aot_stub_routines_updateBytesCRC32C" },
        {"StubRoutines::_updateBytesAdler32", "_aot_stub_routines_updateBytesAdler32" },
        {"StubRoutines::_squareToLen", "_aot_stub_routines_squareToLen" },
        {"StubRoutines::_mulAdd", "_aot_stub_routines_mulAdd" },
        {"StubRoutines::_montgomeryMultiply", "_aot_stub_routines_montgomeryMultiply" },
        {"StubRoutines::_montgomerySquare", "_aot_stub_routines_montgomerySquare" },
        {"StubRoutines::_vectorizedMismatch", "_aot_stub_routines_vectorizedMismatch" },

        {"StubRoutines::_throw_delayed_StackOverflowError_entry", "_aot_stub_routines_throw_delayed_StackOverflowError_entry" },


        {"os::javaTimeMillis", "_aot_os_javaTimeMillis"},
        {"os::javaTimeNanos", "_aot_os_javaTimeNanos"},

        {"JVMCIRuntime::monitorenter", "_aot_jvmci_runtime_monitorenter"},
        {"JVMCIRuntime::monitorexit", "_aot_jvmci_runtime_monitorexit"},
        {"JVMCIRuntime::log_object", "_aot_jvmci_runtime_log_object"},
        {"JVMCIRuntime::log_printf", "_aot_jvmci_runtime_log_printf"},
        {"JVMCIRuntime::vm_message", "_aot_jvmci_runtime_vm_message"},
        {"JVMCIRuntime::new_instance", "_aot_jvmci_runtime_new_instance"},
        {"JVMCIRuntime::log_primitive", "_aot_jvmci_runtime_log_primitive"},
        {"JVMCIRuntime::new_multi_array", "_aot_jvmci_runtime_new_multi_array"},
        {"JVMCIRuntime::validate_object", "_aot_jvmci_runtime_validate_object"},
        {"JVMCIRuntime::dynamic_new_array", "_aot_jvmci_runtime_dynamic_new_array"},
        {"JVMCIRuntime::write_barrier_pre", "_aot_jvmci_runtime_write_barrier_pre"},
        {"JVMCIRuntime::identity_hash_code", "_aot_jvmci_runtime_identity_hash_code"},
        {"JVMCIRuntime::write_barrier_post", "_aot_jvmci_runtime_write_barrier_post"},
        {"JVMCIRuntime::dynamic_new_instance", "_aot_jvmci_runtime_dynamic_new_instance"},
        {"JVMCIRuntime::thread_is_interrupted", "_aot_jvmci_runtime_thread_is_interrupted"},
        {"JVMCIRuntime::exception_handler_for_pc", "_aot_jvmci_runtime_exception_handler_for_pc"},
        {"JVMCIRuntime::test_deoptimize_call_int", "_aot_jvmci_runtime_test_deoptimize_call_int"},

        {"JVMCIRuntime::throw_and_post_jvmti_exception",      "_aot_jvmci_runtime_throw_and_post_jvmti_exception"},
        {"JVMCIRuntime::throw_klass_external_name_exception", "_aot_jvmci_runtime_throw_klass_external_name_exception"},
        {"JVMCIRuntime::throw_class_cast_exception",          "_aot_jvmci_runtime_throw_class_cast_exception"},

        {"JVMCIRuntime::vm_error", "_aot_jvmci_runtime_vm_error"},
        {"JVMCIRuntime::new_array", "_aot_jvmci_runtime_new_array"}
        //@formatter:on
    };

    static {
        for (String[] entry : map) {
            functionNamesToAOTSymbols.put(entry[0], entry[1]);
        }
    }

    
Allocates a BinaryContainer object whose content will be generated in a file with the prefix prefix. It also initializes internal code container, symbol table and relocation tables. 
Params:
graalOptions – /**
     * Allocates a {@code BinaryContainer} object whose content will be generated in a file with the
     * prefix {@code prefix}. It also initializes internal code container, symbol table and
     * relocation tables.
     *
     * @param graalOptions
     */
    public BinaryContainer(OptionValues graalOptions, GraalHotSpotVMConfig graalHotSpotVMConfig, GraphBuilderConfiguration graphBuilderConfig, String jvmVersion) {
        this.graalOptions = graalOptions;

        this.codeSegmentSize = graalHotSpotVMConfig.codeSegmentSize;
        if (codeSegmentSize < 1 || codeSegmentSize > 1024) {
            throw new InternalError("codeSegmentSize is not in range [1, 1024] bytes: (" + codeSegmentSize + "), update JPECoffRelocObject");
        }
        if ((codeSegmentSize & (codeSegmentSize - 1)) != 0) {
            throw new InternalError("codeSegmentSize is not power of 2: (" + codeSegmentSize + "), update JPECoffRelocObject");
        }

        this.codeEntryAlignment = graalHotSpotVMConfig.codeEntryAlignment;

        this.threadLocalHandshakes = graalHotSpotVMConfig.threadLocalHandshakes;

        // Section unique name is limited to 8 characters due to limitation on Windows.
        // Name could be longer but only first 8 characters are stored on Windows.

        // read only, code
        codeContainer = new CodeContainer(".text", this);

        // read only, info
        headerContainer = new HeaderContainer(jvmVersion, new ReadOnlyDataContainer(".header", this));
        configContainer = new ReadOnlyDataContainer(".config", this);
        metaspaceNamesContainer = new ReadOnlyDataContainer(".meta.names", this);
        methodsOffsetsContainer = new ReadOnlyDataContainer(".meth.offsets", this);
        klassesOffsetsContainer = new ReadOnlyDataContainer(".kls.offsets", this);
        klassesDependenciesContainer = new ReadOnlyDataContainer(".kls.dependencies", this);

        stubsOffsetsContainer = new ReadOnlyDataContainer(".stubs.offsets", this);
        codeSegmentsContainer = new ReadOnlyDataContainer(".code.segments", this);
        constantDataContainer = new ReadOnlyDataContainer(".meth.constdata", this);
        methodMetadataContainer = new ReadOnlyDataContainer(".meth.metadata", this);

        // writable sections
        oopGotContainer = new ByteContainer(".oop.got", this);
        klassesGotContainer = new ByteContainer(".kls.got", this);
        countersGotContainer = new ByteContainer(".cnt.got", this);
        metadataGotContainer = new ByteContainer(".meta.got", this);
        methodStateContainer = new ByteContainer(".meth.state", this);
        extLinkageGOTContainer = new ByteContainer(".got.linkage", this);

        addGlobalSymbols();

        recordConfiguration(graalHotSpotVMConfig, graphBuilderConfig);
    }

    private void recordConfiguration(GraalHotSpotVMConfig graalHotSpotVMConfig, GraphBuilderConfiguration graphBuilderConfig) {
        // @formatter:off
        boolean[] booleanFlags = { graalHotSpotVMConfig.cAssertions, // Debug VM
                                   graalHotSpotVMConfig.useCompressedOops,
                                   graalHotSpotVMConfig.useCompressedClassPointers,
                                   graalHotSpotVMConfig.compactFields,
                                   graalHotSpotVMConfig.useG1GC,
                                   graalHotSpotVMConfig.useTLAB,
                                   graalHotSpotVMConfig.useBiasedLocking,
                                   TieredAOT.getValue(graalOptions),
                                   graalHotSpotVMConfig.enableContended,
                                   graalHotSpotVMConfig.restrictContended,
                                   graphBuilderConfig.omitAssertions(),
                                   graalHotSpotVMConfig.threadLocalHandshakes
        };

        int[] intFlags         = { graalHotSpotVMConfig.getOopEncoding().getShift(),
                                   graalHotSpotVMConfig.getKlassEncoding().getShift(),
                                   graalHotSpotVMConfig.contendedPaddingWidth,
                                   graalHotSpotVMConfig.fieldsAllocationStyle,
                                   1 << graalHotSpotVMConfig.logMinObjAlignment(),
                                   graalHotSpotVMConfig.codeSegmentSize,
        };
        // @formatter:on

        byte[] booleanFlagsAsBytes = flagsToByteArray(booleanFlags);
        int size0 = configContainer.getByteStreamSize();

        // @formatter:off
        int computedSize = booleanFlagsAsBytes.length * Byte.BYTES    + // size of boolean flags
                           intFlags.length            * Integer.BYTES + // size of int flags
                           Integer.BYTES;                               // size of the "computedSize"

        configContainer.appendInt(computedSize).
                        appendInts(intFlags).
                        appendBytes(booleanFlagsAsBytes);
        // @formatter:on

        int size = configContainer.getByteStreamSize() - size0;
        assert size == computedSize;
    }

    private static byte[] flagsToByteArray(boolean[] flags) {
        byte[] byteArray = new byte[flags.length];
        for (int i = 0; i < flags.length; ++i) {
            byteArray[i] = boolToByte(flags[i]);
        }
        return byteArray;
    }

    private static byte boolToByte(boolean flag) {
        return (byte) (flag ? 1 : 0);
    }

    
Free some memory.
/**
     * Free some memory.
     */
    public void freeMemory() {
        offsetStringTable.clear();
        metaspaceNames.clear();
    }

    /*
     * Global symbol names in generated DSO corresponding to VM's symbols. VM needs to look up this
     * symbol in DSO and link it with VM's corresponding symbol: store VM's symbol address or value
     * in the named GOT cell.
     */

    public static String getCardTableAddressSymbolName() {
        return "_aot_card_table_address";
    }

    public static String getHeapTopAddressSymbolName() {
        return "_aot_heap_top_address";
    }

    public static String getHeapEndAddressSymbolName() {
        return "_aot_heap_end_address";
    }

    public static String getCrcTableAddressSymbolName() {
        return "_aot_stub_routines_crc_table_adr";
    }

    public static String getPollingPageSymbolName() {
        return "_aot_polling_page";
    }

    public static String getResolveStaticEntrySymbolName() {
        return "_resolve_static_entry";
    }

    public static String getResolveVirtualEntrySymbolName() {
        return "_resolve_virtual_entry";
    }

    public static String getResolveOptVirtualEntrySymbolName() {
        return "_resolve_opt_virtual_entry";
    }

    public static String getNarrowKlassBaseAddressSymbolName() {
        return "_aot_narrow_klass_base_address";
    }

    public static String getNarrowOopBaseAddressSymbolName() {
        return "_aot_narrow_oop_base_address";
    }

    public static String getLogOfHeapRegionGrainBytesSymbolName() {
        return "_aot_log_of_heap_region_grain_bytes";
    }

    public static String getInlineContiguousAllocationSupportedSymbolName() {
        return "_aot_inline_contiguous_allocation_supported";
    }

    public int getCodeSegmentSize() {
        return codeSegmentSize;
    }

    public int getCodeEntryAlignment() {
        return codeEntryAlignment;
    }

    public boolean getThreadLocalHandshakes() {
        return threadLocalHandshakes;
    }


    
Gets the global AOT symbol associated with the function name.
Params:
functionName – function name
Returns:
AOT symbol for the given function name, or null if there is no mapping./**
     * Gets the global AOT symbol associated with the function name.
     *
     * @param functionName function name
     * @return AOT symbol for the given function name, or null if there is no mapping.
     */
    public static String getAOTSymbolForVMFunctionName(String functionName) {
        return functionNamesToAOTSymbols.get(functionName);
    }

    private void addGlobalSymbols() {
        // Create global symbols for all containers.
        createContainerSymbol(codeContainer);
        createContainerSymbol(configContainer);
        createContainerSymbol(methodsOffsetsContainer);
        createContainerSymbol(klassesOffsetsContainer);
        createContainerSymbol(klassesDependenciesContainer);
        createContainerSymbol(klassesGotContainer);
        createContainerSymbol(countersGotContainer);
        createContainerSymbol(metadataGotContainer);
        createContainerSymbol(methodStateContainer);
        createContainerSymbol(oopGotContainer);
        createContainerSymbol(metaspaceNamesContainer);
        createContainerSymbol(methodMetadataContainer);
        createContainerSymbol(stubsOffsetsContainer);
        createContainerSymbol(headerContainer.getContainer());
        createContainerSymbol(codeSegmentsContainer);

        createGotSymbol(getResolveStaticEntrySymbolName());
        createGotSymbol(getResolveVirtualEntrySymbolName());
        createGotSymbol(getResolveOptVirtualEntrySymbolName());
        createGotSymbol(getCardTableAddressSymbolName());
        createGotSymbol(getHeapTopAddressSymbolName());
        createGotSymbol(getHeapEndAddressSymbolName());
        createGotSymbol(getNarrowKlassBaseAddressSymbolName());
        createGotSymbol(getNarrowOopBaseAddressSymbolName());
        createGotSymbol(getPollingPageSymbolName());
        createGotSymbol(getLogOfHeapRegionGrainBytesSymbolName());
        createGotSymbol(getInlineContiguousAllocationSupportedSymbolName());

        for (HashMap.Entry<String, String> entry : functionNamesToAOTSymbols.entrySet()) {
            createGotSymbol(entry.getValue());
        }
    }

    
Creates a global symbol of the form "A" + container name. Note, linker on Windows does not allow names which start with '.' 
Params:
container – container to create a symbol for/**
     * Creates a global symbol of the form {@code "A" + container name}. Note, linker on Windows
     * does not allow names which start with '.'
     *
     * @param container container to create a symbol for
     */
    private static void createContainerSymbol(ByteContainer container) {
        container.createSymbol(0, Kind.OBJECT, Binding.GLOBAL, 0, "A" + container.getContainerName());
    }

    
Creates a global GOT symbol of the form "got." + name. 
Params:
name – name for the GOT symbol/**
     * Creates a global GOT symbol of the form {@code "got." + name}.
     *
     * @param name name for the GOT symbol
     */
    private void createGotSymbol(String name) {
        String s = "got." + name;
        Symbol gotSymbol = extLinkageGOTContainer.createGotSymbol(s);
        extLinkageGOTContainer.createSymbol(gotSymbol.getOffset(), Kind.OBJECT, Binding.GLOBAL, 8, name);
    }

    
Create a platform-specific binary file representing the content of the BinaryContainer object. This method is called after creating and performing any necessary changes to the contents of code stream, symbol tables and relocation tables is completely finalized 
Params:
outputFileName – name of output file
Throws:
IOException – in case of file creation failure/**
     * Create a platform-specific binary file representing the content of the
     * {@code BinaryContainer} object.
     *
     * This method is called after creating and performing any necessary changes to the contents of
     * code stream, symbol tables and relocation tables is completely finalized
     *
     * @param outputFileName name of output file
     *
     * @throws IOException in case of file creation failure
     */
    public void createBinary(String outputFileName) throws IOException {
        String osName = System.getProperty("os.name");
        switch (osName) {
            case "Linux":
            case "SunOS":
                JELFRelocObject elfobj = new JELFRelocObject(this, outputFileName);
                elfobj.createELFRelocObject(relocationTable, symbolTable.values());
                break;
            case "Mac OS X":
                JMachORelocObject machobj = new JMachORelocObject(this, outputFileName);
                machobj.createMachORelocObject(relocationTable, symbolTable.values());
                break;
            default:
                if (osName.startsWith("Windows")) {
                    JPECoffRelocObject pecoffobj = new JPECoffRelocObject(this, outputFileName);
                    pecoffobj.createPECoffRelocObject(relocationTable, symbolTable.values());
                    break;
                } else
                    throw new InternalError("Unsupported platform: " + osName);
        }
    }

    
Add symbol to the symbol table. If the existing symbol is undefined and the specified symbol
is not undefined, replace the existing symbol information with that specified.
Params:
symInfo – symbol information to be added/**
     * Add symbol to the symbol table. If the existing symbol is undefined and the specified symbol
     * is not undefined, replace the existing symbol information with that specified.
     *
     * @param symInfo symbol information to be added
     */
    public void addSymbol(Symbol symInfo) {
        if (symInfo.getName().startsWith("got.") && !(symInfo instanceof GotSymbol)) {
            throw new InternalError("adding got. without being GotSymbol");
        }
        if (symbolTable.containsKey(symInfo.getName())) {
            throw new InternalError("Symbol: " + symInfo.getName() + " already exists in SymbolTable");
        } else {
            // System.out.println("# Symbol [" + name + "] [" + symInfo.getValue() + "] [" +
            // symInfo.getSection().getContainerName() + "] [" + symInfo.getSize() + "]");
            symbolTable.put(symInfo.getName(), symInfo);
        }
    }

    public boolean addStringOffset(String name, Integer offset) {
        offsetStringTable.put(name, offset);
        return true;
    }

    
Add relocation entry for symName. Multiple relocation entries for a given symbol may exist. 
Params:
info – relocation information to be added/**
     * Add relocation entry for {@code symName}. Multiple relocation entries for a given symbol may
     * exist.
     *
     * @param info relocation information to be added
     */
    public void addRelocation(Relocation info) {
        // System.out.println("# Relocation [" + symName + "] [" + info.getOffset() + "] [" +
        // info.getSection().getContainerName() + "] [" + info.getSymbol().getName() + "] [" +
        // info.getSymbol().getOffset() + " @ " + info.getSymbol().getSection().getContainerName() +
        // "]");
        if (relocationTable.containsKey(info.getSymbol())) {
            relocationTable.get(info.getSymbol()).add(info);
        } else if (uniqueRelocationTable.containsKey(info.getSymbol())) {
            // promote
            ArrayList<Relocation> list = new ArrayList<>(2);
            list.add(uniqueRelocationTable.get(info.getSymbol()));
            list.add(info);
            relocationTable.put(info.getSymbol(), list);
            uniqueRelocationTable.remove(info.getSymbol());
        } else {
            uniqueRelocationTable.put(info.getSymbol(), info);
        }
    }

    
Get symbol with name symName. 
Params:
symName – name of symbol for which symbol table information is being queried
Returns:
success or failure of insertion operation/**
     * Get symbol with name {@code symName}.
     *
     * @param symName name of symbol for which symbol table information is being queried
     * @return success or failure of insertion operation
     */
    @Override
    public Symbol getSymbol(String symName) {
        return symbolTable.get(symName);
    }

    @Override
    public Symbol createSymbol(int offset, Kind kind, Binding binding, int size, String name) {
        if (kind != Kind.NATIVE_FUNCTION) {
            throw new UnsupportedOperationException("Must be external functions: " + name);
        }
        Symbol symbol = new Symbol(offset, kind, binding, null, size, name);
        addSymbol(symbol);
        return symbol;
    }

    
Get offset in got section with name symName. 
Params:
name – for which String table information is being queried
Returns:
success or failure of insertion operation/**
     * Get offset in got section with name {@code symName}.
     *
     * @param name for which String table information is being queried
     * @return success or failure of insertion operation
     */
    public Integer getStringOffset(String name) {
        return offsetStringTable.get(name);
    }

    
Insert targetCode to code stream with size at offset. 
Params:
targetCode – byte array of native code
offset – offset at which targetCode is to be inserted
size – size of targetCode/**
     * Insert {@code targetCode} to code stream with {@code size} at {@code offset}.
     *
     * @param targetCode byte array of native code
     * @param offset offset at which {@code targetCode} is to be inserted
     * @param size size of {@code targetCode}
     */
    private static void appendBytes(ByteContainer byteContainer, byte[] targetCode, int offset, int size) {
        byteContainer.appendBytes(targetCode, offset, size);
    }

    public void appendCodeBytes(byte[] targetCode, int offset, int size) {
        appendBytes(codeContainer, targetCode, offset, size);
    }

    public void appendIntToCode(int value) {
        codeContainer.appendInt(value);
    }

    public int appendExtLinkageGotBytes(byte[] bytes, int offset, int size) {
        int startOffset = extLinkageGOTContainer.getByteStreamSize();
        appendBytes(extLinkageGOTContainer, bytes, offset, size);
        return startOffset;
    }

    public void addMetadataGotEntry(int offset) {
        metadataGotContainer.appendLong(offset);
    }

    public int addMetaspaceName(String name) {
        Integer value = metaspaceNames.get(name);
        if (value != null) {
            return value.intValue();
        }
        // Get the current length of the stubsNameContainer
        // align on 8-byte boundary
        int nameOffset = alignUp(metaspaceNamesContainer, 8);

        try {
            // Add the name of the symbol to the .stubs.names section
            // Modify them to sequence of utf8 strings with length:
            // "<u2_size>Ljava/lang/ThreadGroup;<u2_size>addUnstarted<u2_size>()V"
            ByteArrayOutputStream bout = new ByteArrayOutputStream();
            DataOutputStream out = new DataOutputStream(bout);
            int len = name.length();
            if (name.startsWith("Stub")) { // Stub
                out.writeUTF(name);
            } else { // Method or Klass
                int parenthesesIndex = name.lastIndexOf('(', len - 1);
                if (parenthesesIndex > 0) {  // Method name
                    int dotIndex = name.lastIndexOf('.', parenthesesIndex - 1);
                    assert dotIndex > 0 : "method's full name should have '.' : " + name;
                    String klassName = name.substring(0, dotIndex);
                    out.writeUTF(klassName);
                    String methodName = name.substring(dotIndex + 1, parenthesesIndex);
                    out.writeUTF(methodName);
                    String signature = name.substring(parenthesesIndex, len);
                    out.writeUTF(signature);
                } else {
                    out.writeUTF(name); // Klass
                }
            }
            out.writeShort(0); // Terminate by 0.
            byte[] b = bout.toByteArray();
            metaspaceNamesContainer.appendBytes(b, 0, b.length);

            metaspaceNames.put(name, nameOffset);
            return nameOffset;
        } catch (IOException e) {
            throw new InternalError("Failed to append bytes to stubs sections", e);
        }
    }

    
Add oop symbol by as follows. Extend the oop.got section with another slot for the VM to
patch.
Params:
oopName – name of the oop symbol/**
     * Add oop symbol by as follows. Extend the oop.got section with another slot for the VM to
     * patch.
     *
     * @param oopName name of the oop symbol
     */
    public Integer addOopSymbol(String oopName) {
        Integer oopGotOffset = getStringOffset(oopName);
        if (oopGotOffset != null) {
            return oopGotOffset;
        }
        return newOopSymbol(oopName);
    }

    private Integer newOopSymbol(String oopName) {
        // Reference to String resolution (ldc).
        int offset = oopGotContainer.getByteStreamSize();
        String gotName = "got.ldc." + offset;
        Symbol relocationSymbol = oopGotContainer.createGotSymbol(gotName);

        if (offset != relocationSymbol.getOffset()) {
            throw new InternalError("offset must equal! (" + offset + " vs " + relocationSymbol.getOffset());
        }

        addStringOffset(oopName, relocationSymbol.getOffset());
        return relocationSymbol.getOffset();
    }

    public int addCountersSymbol(String metaspaceName) {
        String gotName = "got." + metaspaceName;
        Symbol relocationSymbol = getGotSymbol(gotName);
        int metaspaceOffset = -1;
        if (relocationSymbol == null) {
            // Add slots when asked in the .metaspace.got section:
            countersGotContainer.createGotSymbol(gotName);
        }
        return metaspaceOffset;
    }

    public Symbol getGotSymbol(String name) {
        assert name.startsWith("got.");
        return symbolTable.get(name);
    }

    
Add klass symbol by as follows. - Adding the symbol name to the metaspace.names section - Add
the offset of the name in metaspace.names to metaspace.offsets - Extend the klasses.got
section with another slot for the VM to patch
Params:
klassName – name of the metaspace symbol
Returns:
the got offset in the klasses.got of the metaspace symbol/**
     * Add klass symbol by as follows. - Adding the symbol name to the metaspace.names section - Add
     * the offset of the name in metaspace.names to metaspace.offsets - Extend the klasses.got
     * section with another slot for the VM to patch
     *
     * @param klassName name of the metaspace symbol
     * @return the got offset in the klasses.got of the metaspace symbol
     */
    public int addTwoSlotKlassSymbol(String klassName) {
        String gotName = "got." + klassName;
        Symbol previous = getGotSymbol(gotName);
        assert previous == null : "should be called only once for: " + klassName;
        // Add slots when asked in the .metaspace.got section:
        // First slot
        String gotInitName = "got.init." + klassName;
        GotSymbol slot1Symbol = klassesGotContainer.createGotSymbol(gotInitName);
        GotSymbol slot2Symbol = klassesGotContainer.createGotSymbol(gotName);

        slot1Symbol.getIndex(); // check alignment and ignore result
        // Get the index (offset/8) to the got in the .metaspace.got section
        return slot2Symbol.getIndex();
    }

    public static int addMethodsCount(int count, ReadOnlyDataContainer container) {
        return appendInt(count, container);
    }

    private static int appendInt(int count, ReadOnlyDataContainer container) {
        int offset = container.getByteStreamSize();
        container.appendInt(count);
        return offset;
    }

    
Add constant data as follows. - Adding the data to the meth.constdata section
Params:
data – 
alignment – 
Returns:
the offset in the meth.constdata of the data/**
     * Add constant data as follows. - Adding the data to the meth.constdata section
     *
     * @param data
     * @param alignment
     * @return the offset in the meth.constdata of the data
     */
    public int addConstantData(byte[] data, int alignment) {
        // Get the current length of the metaspaceNameContainer
        int constantDataOffset = alignUp(constantDataContainer, alignment);
        constantDataContainer.appendBytes(data, 0, data.length);
        alignUp(constantDataContainer, alignment); // Post alignment
        return constantDataOffset;
    }

    public static int alignUp(ByteContainer container, int alignment) {
        if (Integer.bitCount(alignment) != 1) {
            throw new IllegalArgumentException("Must be a power of 2");
        }
        int offset = container.getByteStreamSize();
        int aligned = (offset + (alignment - 1)) & -alignment;
        if (aligned < offset || (aligned & (alignment - 1)) != 0) {
            throw new RuntimeException("Error aligning: " + offset + " -> " + aligned);
        }
        if (aligned != offset) {
            int nullArraySz = aligned - offset;
            byte[] nullArray = new byte[nullArraySz];
            container.appendBytes(nullArray, 0, nullArraySz);
            offset = aligned;
        }
        return offset;
    }

    public void addCodeSegments(int start, int end) {
        assert (start % codeSegmentSize) == 0 : "not aligned code";
        int currentOffset = codeSegmentsContainer.getByteStreamSize();
        int offset = start / codeSegmentSize;
        int emptySize = offset - currentOffset;
        // add empty segments if needed
        if (emptySize > 0) {
            byte[] emptyArray = new byte[emptySize];
            for (int i = 0; i < emptySize; i++) {
                emptyArray[i] = (byte) 0xff;
            }
            appendBytes(codeSegmentsContainer, emptyArray, 0, emptySize);
        }
        int alignedEnd = (end + (codeSegmentSize - 1)) & -codeSegmentSize;
        int segmentsCount = (alignedEnd / codeSegmentSize) - offset;
        byte[] segments = new byte[segmentsCount];
        int idx = 0;
        for (int i = 0; i < segmentsCount; i++) {
            segments[i] = (byte) idx;
            idx = (idx == 0xfe) ? 1 : (idx + 1);
        }
        appendBytes(codeSegmentsContainer, segments, 0, segmentsCount);
    }

    public ByteContainer getExtLinkageGOTContainer() {
        return extLinkageGOTContainer;
    }

    public ReadOnlyDataContainer getMethodMetadataContainer() {
        return methodMetadataContainer;
    }

    public ReadOnlyDataContainer getMetaspaceNamesContainer() {
        return metaspaceNamesContainer;
    }

    public ReadOnlyDataContainer getMethodsOffsetsContainer() {
        return methodsOffsetsContainer;
    }

    public ReadOnlyDataContainer getKlassesOffsetsContainer() {
        return klassesOffsetsContainer;
    }

    public ReadOnlyDataContainer getKlassesDependenciesContainer() {
        return klassesDependenciesContainer;
    }

    public ReadOnlyDataContainer getStubsOffsetsContainer() {
        return stubsOffsetsContainer;
    }

    public ReadOnlyDataContainer getCodeSegmentsContainer() {
        return codeSegmentsContainer;
    }

    public ReadOnlyDataContainer getConstantDataContainer() {
        return constantDataContainer;
    }

    public ByteContainer getKlassesGotContainer() {
        return klassesGotContainer;
    }

    public ByteContainer getCountersGotContainer() {
        return countersGotContainer;
    }

    public ByteContainer getMetadataGotContainer() {
        return metadataGotContainer;
    }

    public ByteContainer getMethodStateContainer() {
        return methodStateContainer;
    }

    public ByteContainer getOopGotContainer() {
        return oopGotContainer;
    }

    public CodeContainer getCodeContainer() {
        return codeContainer;
    }

    public ReadOnlyDataContainer getConfigContainer() {
        return configContainer;
    }

    public Map<Symbol, Relocation> getUniqueRelocationTable() {
        return uniqueRelocationTable;
    }

    public HeaderContainer getHeaderContainer() {
        return headerContainer;
    }

}