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 /*

  * Copyright (c) 1997, 2011, 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"

 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 {

  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*        _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 RicochetBlob*       _ricochet_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:

   static SafepointBlob* generate_handler_blob(address call_ptr, bool cause_return);

   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);

 #ifndef SERIALGC

   // G1 write barriers

   static void g1_wb_pre(oopDesc* orig, JavaThread *thread);

   static void g1_wb_post(void* card_addr, JavaThread* thread);

 #endif // !SERIALGC

   // 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();

   }

 #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 RicochetBlob* ricochet_blob() {

 #ifdef X86

     // Currently only implemented on x86

     assert(!EnableInvokeDynamic || _ricochet_blob != NULL, "oops");

 #endif

     return _ricochet_blob;

   }

   static void generate_ricochet_blob();

   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; }

   // 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, methodOopDesc* m);

   // To be used as the entry point for unresolved native methods.

   static address native_method_throw_unsatisfied_link_error_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, methodOopDesc* m);

   static int dtrace_method_exit(JavaThread* thread, methodOopDesc* 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 message for a WrongMethodTypeException

    *

    * @param thr the current thread

    * @param mtype (optional) expected method type (or argument class)

    * @param mhandle (optional) actual method handle (or argument)

    * @return the dynamically allocated exception message

    *

    * BCP for the frame on top of the stack must refer to an

    * 'invokevirtual' op for a method handle, or an 'invokedyamic' op.

    * The caller (or one of its callers) must use a ResourceMark

    * in order to correctly free the result.

    */

   static char* generate_wrong_method_type_message(JavaThread* thr,

                                                   oopDesc* mtype = NULL,

                                                   oopDesc* mhandle = NULL);

   /** Return non-null if the mtype is a klass or Class, not a MethodType. */

   static oop wrong_method_type_is_for_single_argument(JavaThread* thr,

                                                       oopDesc* mtype);

   /**

    * 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);

   // 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, 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();

   // 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.

   static nmethod *generate_native_wrapper(MacroAssembler* masm,

                                           methodHandle method,

                                           int compile_id,

                                           int total_args_passed,

                                           int max_arg,

                                           BasicType *sig_bt,

                                           VMRegPair *regs,

                                           BasicType ret_type );

 #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(methodOopDesc* 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_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 {

   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()            { return _i2c_entry; }

   address get_c2i_entry()            { return _c2i_entry; }

   address get_c2i_unverified_entry() { return _c2i_unverified_entry; }

   void relocate(address new_base);

   AdapterFingerPrint* fingerprint()  { return _fingerprint; }

   AdapterHandlerEntry* next() {

     return (AdapterHandlerEntry*)BasicHashtableEntry::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

   void print();

 };

 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