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Java example source code file (sharedRuntime.hpp)

This example Java source code file (sharedRuntime.hpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

adapterfingerprint, adapterhandlerentry, assert, basictype, compiler2, have_dtrace_h, javathread, null, product, runtimestub, safepointblob, slow-path, traps, vmregpair

The sharedRuntime.hpp Java example source code

/*
 * Copyright (c) 1997, 2013, 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.
 *
 */

#ifndef SHARE_VM_RUNTIME_SHAREDRUNTIME_HPP
#define SHARE_VM_RUNTIME_SHAREDRUNTIME_HPP

#include "interpreter/bytecodeHistogram.hpp"
#include "interpreter/bytecodeTracer.hpp"
#include "interpreter/linkResolver.hpp"
#include "memory/allocation.hpp"
#include "memory/resourceArea.hpp"
#include "runtime/threadLocalStorage.hpp"
#include "utilities/hashtable.hpp"
#include "utilities/macros.hpp"

class AdapterHandlerEntry;
class AdapterHandlerTable;
class AdapterFingerPrint;
class vframeStream;

// Runtime is the base class for various runtime interfaces
// (InterpreterRuntime, CompilerRuntime, etc.). It provides
// shared functionality such as exception forwarding (C++ to
// Java exceptions), locking/unlocking mechanisms, statistical
// information, etc.

class SharedRuntime: AllStatic {
  friend class VMStructs;

 private:
  static methodHandle resolve_sub_helper(JavaThread *thread,
                                     bool is_virtual,
                                     bool is_optimized, TRAPS);

  // Shared stub locations

  static RuntimeStub*        _wrong_method_blob;
  static RuntimeStub*        _wrong_method_abstract_blob;
  static RuntimeStub*        _ic_miss_blob;
  static RuntimeStub*        _resolve_opt_virtual_call_blob;
  static RuntimeStub*        _resolve_virtual_call_blob;
  static RuntimeStub*        _resolve_static_call_blob;

  static DeoptimizationBlob* _deopt_blob;

  static SafepointBlob*      _polling_page_vectors_safepoint_handler_blob;
  static SafepointBlob*      _polling_page_safepoint_handler_blob;
  static SafepointBlob*      _polling_page_return_handler_blob;

#ifdef COMPILER2
  static UncommonTrapBlob*   _uncommon_trap_blob;
#endif // COMPILER2

#ifndef PRODUCT
  // Counters
  static int     _nof_megamorphic_calls;         // total # of megamorphic calls (through vtable)
#endif // !PRODUCT

 private:
  enum { POLL_AT_RETURN,  POLL_AT_LOOP, POLL_AT_VECTOR_LOOP };
  static SafepointBlob* generate_handler_blob(address call_ptr, int poll_type);
  static RuntimeStub*   generate_resolve_blob(address destination, const char* name);

 public:
  static void generate_stubs(void);

  // max bytes for each dtrace string parameter
  enum { max_dtrace_string_size = 256 };

  // The following arithmetic routines are used on platforms that do
  // not have machine instructions to implement their functionality.
  // Do not remove these.

  // long arithmetics
  static jlong   lmul(jlong y, jlong x);
  static jlong   ldiv(jlong y, jlong x);
  static jlong   lrem(jlong y, jlong x);

  // float and double remainder
  static jfloat  frem(jfloat  x, jfloat  y);
  static jdouble drem(jdouble x, jdouble y);

#ifdef __SOFTFP__
  static jfloat  fadd(jfloat x, jfloat y);
  static jfloat  fsub(jfloat x, jfloat y);
  static jfloat  fmul(jfloat x, jfloat y);
  static jfloat  fdiv(jfloat x, jfloat y);

  static jdouble dadd(jdouble x, jdouble y);
  static jdouble dsub(jdouble x, jdouble y);
  static jdouble dmul(jdouble x, jdouble y);
  static jdouble ddiv(jdouble x, jdouble y);
#endif // __SOFTFP__

  // float conversion (needs to set appropriate rounding mode)
  static jint    f2i (jfloat  x);
  static jlong   f2l (jfloat  x);
  static jint    d2i (jdouble x);
  static jlong   d2l (jdouble x);
  static jfloat  d2f (jdouble x);
  static jfloat  l2f (jlong   x);
  static jdouble l2d (jlong   x);

#ifdef __SOFTFP__
  static jfloat  i2f (jint    x);
  static jdouble i2d (jint    x);
  static jdouble f2d (jfloat  x);
#endif // __SOFTFP__

  // double trigonometrics and transcendentals
  static jdouble dsin(jdouble x);
  static jdouble dcos(jdouble x);
  static jdouble dtan(jdouble x);
  static jdouble dlog(jdouble x);
  static jdouble dlog10(jdouble x);
  static jdouble dexp(jdouble x);
  static jdouble dpow(jdouble x, jdouble y);

#if defined(__SOFTFP__) || defined(E500V2)
  static double dabs(double f);
#endif

#if defined(__SOFTFP__) || defined(PPC)
  static double dsqrt(double f);
#endif

#ifdef __SOFTFP__
  // C++ compiler generates soft float instructions as well as passing
  // float and double in registers.
  static int  fcmpl(float x, float y);
  static int  fcmpg(float x, float y);
  static int  dcmpl(double x, double y);
  static int  dcmpg(double x, double y);

  static int unordered_fcmplt(float x, float y);
  static int unordered_dcmplt(double x, double y);
  static int unordered_fcmple(float x, float y);
  static int unordered_dcmple(double x, double y);
  static int unordered_fcmpge(float x, float y);
  static int unordered_dcmpge(double x, double y);
  static int unordered_fcmpgt(float x, float y);
  static int unordered_dcmpgt(double x, double y);

  static float  fneg(float f);
  static double dneg(double f);
#endif

  // exception handling across interpreter/compiler boundaries
  static address raw_exception_handler_for_return_address(JavaThread* thread, address return_address);
  static address exception_handler_for_return_address(JavaThread* thread, address return_address);

#if INCLUDE_ALL_GCS
  // G1 write barriers
  static void g1_wb_pre(oopDesc* orig, JavaThread *thread);
  static void g1_wb_post(void* card_addr, JavaThread* thread);
#endif // INCLUDE_ALL_GCS

  // exception handling and implicit exceptions
  static address compute_compiled_exc_handler(nmethod* nm, address ret_pc, Handle& exception,
                                              bool force_unwind, bool top_frame_only);
  enum ImplicitExceptionKind {
    IMPLICIT_NULL,
    IMPLICIT_DIVIDE_BY_ZERO,
    STACK_OVERFLOW
  };
  static void    throw_AbstractMethodError(JavaThread* thread);
  static void    throw_IncompatibleClassChangeError(JavaThread* thread);
  static void    throw_ArithmeticException(JavaThread* thread);
  static void    throw_NullPointerException(JavaThread* thread);
  static void    throw_NullPointerException_at_call(JavaThread* thread);
  static void    throw_StackOverflowError(JavaThread* thread);
  static address continuation_for_implicit_exception(JavaThread* thread,
                                                     address faulting_pc,
                                                     ImplicitExceptionKind exception_kind);

  // Shared stub locations
  static address get_poll_stub(address pc);

  static address get_ic_miss_stub() {
    assert(_ic_miss_blob!= NULL, "oops");
    return _ic_miss_blob->entry_point();
  }

  static address get_handle_wrong_method_stub() {
    assert(_wrong_method_blob!= NULL, "oops");
    return _wrong_method_blob->entry_point();
  }

  static address get_handle_wrong_method_abstract_stub() {
    assert(_wrong_method_abstract_blob!= NULL, "oops");
    return _wrong_method_abstract_blob->entry_point();
  }

#ifdef COMPILER2
  static void generate_uncommon_trap_blob(void);
  static UncommonTrapBlob* uncommon_trap_blob()                  { return _uncommon_trap_blob; }
#endif // COMPILER2

  static address get_resolve_opt_virtual_call_stub(){
    assert(_resolve_opt_virtual_call_blob != NULL, "oops");
    return _resolve_opt_virtual_call_blob->entry_point();
  }
  static address get_resolve_virtual_call_stub() {
    assert(_resolve_virtual_call_blob != NULL, "oops");
    return _resolve_virtual_call_blob->entry_point();
  }
  static address get_resolve_static_call_stub() {
    assert(_resolve_static_call_blob != NULL, "oops");
    return _resolve_static_call_blob->entry_point();
  }

  static SafepointBlob* polling_page_return_handler_blob()     { return _polling_page_return_handler_blob; }
  static SafepointBlob* polling_page_safepoint_handler_blob()  { return _polling_page_safepoint_handler_blob; }
  static SafepointBlob* polling_page_vectors_safepoint_handler_blob()  { return _polling_page_vectors_safepoint_handler_blob; }

  // Counters
#ifndef PRODUCT
  static address nof_megamorphic_calls_addr() { return (address)&_nof_megamorphic_calls; }
#endif // PRODUCT

  // Helper routine for full-speed JVMTI exception throwing support
  static void throw_and_post_jvmti_exception(JavaThread *thread, Handle h_exception);
  static void throw_and_post_jvmti_exception(JavaThread *thread, Symbol* name, const char *message = NULL);

  // RedefineClasses() tracing support for obsolete method entry
  static int rc_trace_method_entry(JavaThread* thread, Method* m);

  // To be used as the entry point for unresolved native methods.
  static address native_method_throw_unsatisfied_link_error_entry();
  static address native_method_throw_unsupported_operation_exception_entry();

  // bytecode tracing is only used by the TraceBytecodes
  static intptr_t trace_bytecode(JavaThread* thread, intptr_t preserve_this_value, intptr_t tos, intptr_t tos2) PRODUCT_RETURN0;

  // Used to back off a spin lock that is under heavy contention
  static void yield_all(JavaThread* thread, int attempts = 0);

  static oop retrieve_receiver( Symbol* sig, frame caller );

  static void register_finalizer(JavaThread* thread, oopDesc* obj);

  // dtrace notifications
  static int dtrace_object_alloc(oopDesc* o);
  static int dtrace_object_alloc_base(Thread* thread, oopDesc* o);
  static int dtrace_method_entry(JavaThread* thread, Method* m);
  static int dtrace_method_exit(JavaThread* thread, Method* m);

  // Utility method for retrieving the Java thread id, returns 0 if the
  // thread is not a well formed Java thread.
  static jlong get_java_tid(Thread* thread);


  // used by native wrappers to reenable yellow if overflow happened in native code
  static void reguard_yellow_pages();

  /**
   * Fill in the "X cannot be cast to a Y" message for ClassCastException
   *
   * @param thr the current thread
   * @param name the name of the class of the object attempted to be cast
   * @return the dynamically allocated exception message (must be freed
   * by the caller using a resource mark)
   *
   * BCP must refer to the current 'checkcast' opcode for the frame
   * on top of the stack.
   * The caller (or one of it's callers) must use a ResourceMark
   * in order to correctly free the result.
   */
  static char* generate_class_cast_message(JavaThread* thr, const char* name);

  /**
   * Fill in the "X cannot be cast to a Y" message for ClassCastException
   *
   * @param name the name of the class of the object attempted to be cast
   * @param klass the name of the target klass attempt
   * @param gripe the specific kind of problem being reported
   * @return the dynamically allocated exception message (must be freed
   * by the caller using a resource mark)
   *
   * This version does not require access the frame, so it can be called
   * from interpreted code
   * The caller (or one of it's callers) must use a ResourceMark
   * in order to correctly free the result.
   */
  static char* generate_class_cast_message(const char* name, const char* klass,
                                           const char* gripe = " cannot be cast to ");

  // Resolves a call site- may patch in the destination of the call into the
  // compiled code.
  static methodHandle resolve_helper(JavaThread *thread,
                                     bool is_virtual,
                                     bool is_optimized, TRAPS);

  private:
  // deopt blob
  static void generate_deopt_blob(void);

  public:
  static DeoptimizationBlob* deopt_blob(void)      { return _deopt_blob; }

  // Resets a call-site in compiled code so it will get resolved again.
  static methodHandle reresolve_call_site(JavaThread *thread, TRAPS);

  // In the code prolog, if the klass comparison fails, the inline cache
  // misses and the call site is patched to megamorphic
  static methodHandle handle_ic_miss_helper(JavaThread* thread, TRAPS);

  // Find the method that called us.
  static methodHandle find_callee_method(JavaThread* thread, TRAPS);


 private:
  static Handle find_callee_info(JavaThread* thread,
                                 Bytecodes::Code& bc,
                                 CallInfo& callinfo, TRAPS);
  static Handle find_callee_info_helper(JavaThread* thread,
                                        vframeStream& vfst,
                                        Bytecodes::Code& bc,
                                        CallInfo& callinfo, TRAPS);

  static address clean_virtual_call_entry();
  static address clean_opt_virtual_call_entry();
  static address clean_static_call_entry();

 public:

  // Read the array of BasicTypes from a Java signature, and compute where
  // compiled Java code would like to put the results.  Values in reg_lo and
  // reg_hi refer to 4-byte quantities.  Values less than SharedInfo::stack0 are
  // registers, those above refer to 4-byte stack slots.  All stack slots are
  // based off of the window top.  SharedInfo::stack0 refers to the first usable
  // slot in the bottom of the frame. SharedInfo::stack0+1 refers to the memory word
  // 4-bytes higher. So for sparc because the register window save area is at
  // the bottom of the frame the first 16 words will be skipped and SharedInfo::stack0
  // will be just above it. (
  // return value is the maximum number of VMReg stack slots the convention will use.
  static int java_calling_convention(const BasicType* sig_bt, VMRegPair* regs, int total_args_passed, int is_outgoing);

  static void check_member_name_argument_is_last_argument(methodHandle method,
                                                          const BasicType* sig_bt,
                                                          const VMRegPair* regs) NOT_DEBUG_RETURN;

  // Ditto except for calling C
  static int c_calling_convention(const BasicType *sig_bt, VMRegPair *regs, int total_args_passed);

  // Generate I2C and C2I adapters. These adapters are simple argument marshalling
  // blobs. Unlike adapters in the tiger and earlier releases the code in these
  // blobs does not create a new frame and are therefore virtually invisible
  // to the stack walking code. In general these blobs extend the callers stack
  // as needed for the conversion of argument locations.

  // When calling a c2i blob the code will always call the interpreter even if
  // by the time we reach the blob there is compiled code available. This allows
  // the blob to pass the incoming stack pointer (the sender sp) in a known
  // location for the interpreter to record. This is used by the frame code
  // to correct the sender code to match up with the stack pointer when the
  // thread left the compiled code. In addition it allows the interpreter
  // to remove the space the c2i adapter allocated to do it argument conversion.

  // Although a c2i blob will always run interpreted even if compiled code is
  // present if we see that compiled code is present the compiled call site
  // will be patched/re-resolved so that later calls will run compiled.

  // Aditionally a c2i blob need to have a unverified entry because it can be reached
  // in situations where the call site is an inlined cache site and may go megamorphic.

  // A i2c adapter is simpler than the c2i adapter. This is because it is assumed
  // that the interpreter before it does any call dispatch will record the current
  // stack pointer in the interpreter frame. On return it will restore the stack
  // pointer as needed. This means the i2c adapter code doesn't need any special
  // handshaking path with compiled code to keep the stack walking correct.

  static AdapterHandlerEntry* generate_i2c2i_adapters(MacroAssembler *_masm,
                                                      int total_args_passed,
                                                      int max_arg,
                                                      const BasicType *sig_bt,
                                                      const VMRegPair *regs,
                                                      AdapterFingerPrint* fingerprint);

  // OSR support

  // OSR_migration_begin will extract the jvm state from an interpreter
  // frame (locals, monitors) and store the data in a piece of C heap
  // storage. This then allows the interpreter frame to be removed from the
  // stack and the OSR nmethod to be called. That method is called with a
  // pointer to the C heap storage. This pointer is the return value from
  // OSR_migration_begin.

  static intptr_t* OSR_migration_begin( JavaThread *thread);

  // OSR_migration_end is a trivial routine. It is called after the compiled
  // method has extracted the jvm state from the C heap that OSR_migration_begin
  // created. It's entire job is to simply free this storage.
  static void      OSR_migration_end  ( intptr_t* buf);

  // Convert a sig into a calling convention register layout
  // and find interesting things about it.
  static VMRegPair* find_callee_arguments(Symbol* sig, bool has_receiver, bool has_appendix, int *arg_size);
  static VMReg     name_for_receiver();

  // "Top of Stack" slots that may be unused by the calling convention but must
  // otherwise be preserved.
  // On Intel these are not necessary and the value can be zero.
  // On Sparc this describes the words reserved for storing a register window
  // when an interrupt occurs.
  static uint out_preserve_stack_slots();

  // Is vector's size (in bytes) bigger than a size saved by default?
  // For example, on x86 16 bytes XMM registers are saved by default.
  static bool is_wide_vector(int size);

  // Save and restore a native result
  static void    save_native_result(MacroAssembler *_masm, BasicType ret_type, int frame_slots );
  static void restore_native_result(MacroAssembler *_masm, BasicType ret_type, int frame_slots );

  // Generate a native wrapper for a given method.  The method takes arguments
  // in the Java compiled code convention, marshals them to the native
  // convention (handlizes oops, etc), transitions to native, makes the call,
  // returns to java state (possibly blocking), unhandlizes any result and
  // returns.
  //
  // The wrapper may contain special-case code if the given method
  // is a JNI critical method, or a compiled method handle adapter,
  // such as _invokeBasic, _linkToVirtual, etc.
  static nmethod* generate_native_wrapper(MacroAssembler* masm,
                                          methodHandle method,
                                          int compile_id,
                                          BasicType* sig_bt,
                                          VMRegPair* regs,
                                          BasicType ret_type );

  // Block before entering a JNI critical method
  static void block_for_jni_critical(JavaThread* thread);

#ifdef HAVE_DTRACE_H
  // Generate a dtrace wrapper for a given method.  The method takes arguments
  // in the Java compiled code convention, marshals them to the native
  // convention (handlizes oops, etc), transitions to native, makes the call,
  // returns to java state (possibly blocking), unhandlizes any result and
  // returns.
  static nmethod *generate_dtrace_nmethod(MacroAssembler* masm,
                                          methodHandle method);

  // dtrace support to convert a Java string to utf8
  static void get_utf(oopDesc* src, address dst);
#endif // def HAVE_DTRACE_H

  // A compiled caller has just called the interpreter, but compiled code
  // exists.  Patch the caller so he no longer calls into the interpreter.
  static void fixup_callers_callsite(Method* moop, address ret_pc);

  // Slow-path Locking and Unlocking
  static void complete_monitor_locking_C(oopDesc* obj, BasicLock* lock, JavaThread* thread);
  static void complete_monitor_unlocking_C(oopDesc* obj, BasicLock* lock);

  // Resolving of calls
  static address resolve_static_call_C     (JavaThread *thread);
  static address resolve_virtual_call_C    (JavaThread *thread);
  static address resolve_opt_virtual_call_C(JavaThread *thread);

  // arraycopy, the non-leaf version.  (See StubRoutines for all the leaf calls.)
  static void slow_arraycopy_C(oopDesc* src,  jint src_pos,
                               oopDesc* dest, jint dest_pos,
                               jint length, JavaThread* thread);

  // handle ic miss with caller being compiled code
  // wrong method handling (inline cache misses, zombie methods)
  static address handle_wrong_method(JavaThread* thread);
  static address handle_wrong_method_abstract(JavaThread* thread);
  static address handle_wrong_method_ic_miss(JavaThread* thread);

#ifndef PRODUCT

  // Collect and print inline cache miss statistics
 private:
  enum { maxICmiss_count = 100 };
  static int     _ICmiss_index;                  // length of IC miss histogram
  static int     _ICmiss_count[maxICmiss_count]; // miss counts
  static address _ICmiss_at[maxICmiss_count];    // miss addresses
  static void trace_ic_miss(address at);

 public:
  static int _monitor_enter_ctr;                 // monitor enter slow
  static int _monitor_exit_ctr;                  // monitor exit slow
  static int _throw_null_ctr;                    // throwing a null-pointer exception
  static int _ic_miss_ctr;                       // total # of IC misses
  static int _wrong_method_ctr;
  static int _resolve_static_ctr;
  static int _resolve_virtual_ctr;
  static int _resolve_opt_virtual_ctr;
  static int _implicit_null_throws;
  static int _implicit_div0_throws;

  static int _jbyte_array_copy_ctr;        // Slow-path byte array copy
  static int _jshort_array_copy_ctr;       // Slow-path short array copy
  static int _jint_array_copy_ctr;         // Slow-path int array copy
  static int _jlong_array_copy_ctr;        // Slow-path long array copy
  static int _oop_array_copy_ctr;          // Slow-path oop array copy
  static int _checkcast_array_copy_ctr;    // Slow-path oop array copy, with cast
  static int _unsafe_array_copy_ctr;       // Slow-path includes alignment checks
  static int _generic_array_copy_ctr;      // Slow-path includes type decoding
  static int _slow_array_copy_ctr;         // Slow-path failed out to a method call

  static int _new_instance_ctr;            // 'new' object requires GC
  static int _new_array_ctr;               // 'new' array requires GC
  static int _multi1_ctr, _multi2_ctr, _multi3_ctr, _multi4_ctr, _multi5_ctr;
  static int _find_handler_ctr;            // find exception handler
  static int _rethrow_ctr;                 // rethrow exception
  static int _mon_enter_stub_ctr;          // monitor enter stub
  static int _mon_exit_stub_ctr;           // monitor exit stub
  static int _mon_enter_ctr;               // monitor enter slow
  static int _mon_exit_ctr;                // monitor exit slow
  static int _partial_subtype_ctr;         // SubRoutines::partial_subtype_check

  // Statistics code
  // stats for "normal" compiled calls (non-interface)
  static int     _nof_normal_calls;              // total # of calls
  static int     _nof_optimized_calls;           // total # of statically-bound calls
  static int     _nof_inlined_calls;             // total # of inlined normal calls
  static int     _nof_static_calls;              // total # of calls to static methods or super methods (invokespecial)
  static int     _nof_inlined_static_calls;      // total # of inlined static calls
  // stats for compiled interface calls
  static int     _nof_interface_calls;           // total # of compiled calls
  static int     _nof_optimized_interface_calls; // total # of statically-bound interface calls
  static int     _nof_inlined_interface_calls;   // total # of inlined interface calls
  static int     _nof_megamorphic_interface_calls;// total # of megamorphic interface calls
  // stats for runtime exceptions
  static int     _nof_removable_exceptions;      // total # of exceptions that could be replaced by branches due to inlining

 public: // for compiler
  static address nof_normal_calls_addr()                { return (address)&_nof_normal_calls; }
  static address nof_optimized_calls_addr()             { return (address)&_nof_optimized_calls; }
  static address nof_inlined_calls_addr()               { return (address)&_nof_inlined_calls; }
  static address nof_static_calls_addr()                { return (address)&_nof_static_calls; }
  static address nof_inlined_static_calls_addr()        { return (address)&_nof_inlined_static_calls; }
  static address nof_interface_calls_addr()             { return (address)&_nof_interface_calls; }
  static address nof_optimized_interface_calls_addr()   { return (address)&_nof_optimized_interface_calls; }
  static address nof_inlined_interface_calls_addr()     { return (address)&_nof_inlined_interface_calls; }
  static address nof_megamorphic_interface_calls_addr() { return (address)&_nof_megamorphic_interface_calls; }
  static void print_call_statistics(int comp_total);
  static void print_statistics();
  static void print_ic_miss_histogram();

#endif // PRODUCT
};


// ---------------------------------------------------------------------------
// Implementation of AdapterHandlerLibrary
//
// This library manages argument marshaling adapters and native wrappers.
// There are 2 flavors of adapters: I2C and C2I.
//
// The I2C flavor takes a stock interpreted call setup, marshals the
// arguments for a Java-compiled call, and jumps to Rmethod-> code()->
// code_begin().  It is broken to call it without an nmethod assigned.
// The usual behavior is to lift any register arguments up out of the
// stack and possibly re-pack the extra arguments to be contigious.
// I2C adapters will save what the interpreter's stack pointer will be
// after arguments are popped, then adjust the interpreter's frame
// size to force alignment and possibly to repack the arguments.
// After re-packing, it jumps to the compiled code start.  There are
// no safepoints in this adapter code and a GC cannot happen while
// marshaling is in progress.
//
// The C2I flavor takes a stock compiled call setup plus the target method in
// Rmethod, marshals the arguments for an interpreted call and jumps to
// Rmethod->_i2i_entry.  On entry, the interpreted frame has not yet been
// setup.  Compiled frames are fixed-size and the args are likely not in the
// right place.  Hence all the args will likely be copied into the
// interpreter's frame, forcing that frame to grow.  The compiled frame's
// outgoing stack args will be dead after the copy.
//
// Native wrappers, like adapters, marshal arguments.  Unlike adapters they
// also perform an offical frame push & pop.  They have a call to the native
// routine in their middles and end in a return (instead of ending in a jump).
// The native wrappers are stored in real nmethods instead of the BufferBlobs
// used by the adapters.  The code generation happens here because it's very
// similar to what the adapters have to do.

class AdapterHandlerEntry : public BasicHashtableEntry<mtCode> {
  friend class AdapterHandlerTable;

 private:
  AdapterFingerPrint* _fingerprint;
  address _i2c_entry;
  address _c2i_entry;
  address _c2i_unverified_entry;

#ifdef ASSERT
  // Captures code and signature used to generate this adapter when
  // verifing adapter equivalence.
  unsigned char* _saved_code;
  int            _code_length;
  BasicType*     _saved_sig;
  int            _total_args_passed;
#endif

  void init(AdapterFingerPrint* fingerprint, address i2c_entry, address c2i_entry, address c2i_unverified_entry) {
    _fingerprint = fingerprint;
    _i2c_entry = i2c_entry;
    _c2i_entry = c2i_entry;
    _c2i_unverified_entry = c2i_unverified_entry;
#ifdef ASSERT
    _saved_code = NULL;
    _code_length = 0;
    _saved_sig = NULL;
    _total_args_passed = 0;
#endif
  }

  void deallocate();

  // should never be used
  AdapterHandlerEntry();

 public:
  address get_i2c_entry()            const { return _i2c_entry; }
  address get_c2i_entry()            const { return _c2i_entry; }
  address get_c2i_unverified_entry() const { return _c2i_unverified_entry; }

  address base_address();
  void relocate(address new_base);

  AdapterFingerPrint* fingerprint() const { return _fingerprint; }

  AdapterHandlerEntry* next() {
    return (AdapterHandlerEntry*)BasicHashtableEntry<mtCode>::next();
  }

#ifdef ASSERT
  // Used to verify that code generated for shared adapters is equivalent
  void save_code(unsigned char* code, int length, int total_args_passed, BasicType* sig_bt);
  bool compare_code(unsigned char* code, int length, int total_args_passed, BasicType* sig_bt);
#endif

  //virtual void print_on(outputStream* st) const;  DO NOT USE
  void print_adapter_on(outputStream* st) const;
};

class AdapterHandlerLibrary: public AllStatic {
 private:
  static BufferBlob* _buffer; // the temporary code buffer in CodeCache
  static AdapterHandlerTable* _adapters;
  static AdapterHandlerEntry* _abstract_method_handler;
  static BufferBlob* buffer_blob();
  static void initialize();

 public:

  static AdapterHandlerEntry* new_entry(AdapterFingerPrint* fingerprint,
                                        address i2c_entry, address c2i_entry, address c2i_unverified_entry);
  static nmethod* create_native_wrapper(methodHandle method, int compile_id);
  static AdapterHandlerEntry* get_adapter(methodHandle method);

#ifdef HAVE_DTRACE_H
  static nmethod* create_dtrace_nmethod (methodHandle method);
#endif // HAVE_DTRACE_H

  static void print_handler(CodeBlob* b) { print_handler_on(tty, b); }
  static void print_handler_on(outputStream* st, CodeBlob* b);
  static bool contains(CodeBlob* b);
#ifndef PRODUCT
  static void print_statistics();
#endif /* PRODUCT */

};

#endif // SHARE_VM_RUNTIME_SHAREDRUNTIME_HPP

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