JDK14/Java14源码在线阅读
/*
* Copyright (c) 1997, 2019, 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
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#ifndef SHARE_RUNTIME_SHAREDRUNTIME_HPP
#define SHARE_RUNTIME_SHAREDRUNTIME_HPP
#include "interpreter/bytecodeHistogram.hpp"
#include "interpreter/bytecodeTracer.hpp"
#include "interpreter/linkResolver.hpp"
#include "memory/allocation.hpp"
#include "memory/resourceArea.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 bool resolve_sub_helper_internal(methodHandle callee_method, const frame& caller_frame,
CompiledMethod* caller_nm, bool is_virtual, bool is_optimized,
Handle receiver, CallInfo& call_info, Bytecodes::Code invoke_code, TRAPS);
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 address _resolve_static_call_entry;
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 _WIN64
// Workaround for fmod issue in the Windows x64 CRT
static double fmod_winx64(double x, double y);
#endif
#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
// Montgomery multiplication
static void montgomery_multiply(jint *a_ints, jint *b_ints, jint *n_ints,
jint len, jlong inv, jint *m_ints);
static void montgomery_square(jint *a_ints, jint *n_ints,
jint len, jlong inv, jint *m_ints);
#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);
// exception handling and implicit exceptions
static address compute_compiled_exc_handler(CompiledMethod* nm, address ret_pc, Handle& exception,
bool force_unwind, bool top_frame_only, bool& recursive_exception_occurred);
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 void throw_delayed_StackOverflowError(JavaThread* thread);
static void throw_StackOverflowError_common(JavaThread* thread, bool delayed);
static address continuation_for_implicit_exception(JavaThread* thread,
address faulting_pc,
ImplicitExceptionKind exception_kind);
// Post-slow-path-allocation, pre-initializing-stores step for
// implementing e.g. ReduceInitialCardMarks
static void on_slowpath_allocation_exit(JavaThread* thread);
static void enable_stack_reserved_zone(JavaThread* thread);
static frame look_for_reserved_stack_annotated_method(JavaThread* thread, frame fr);
// 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();
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, int size);
static int dtrace_object_alloc_base(Thread* thread, oopDesc* o, int size);
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 caster_klass the class of the object we are casting
// @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 its callers) must use a ResourceMark
// in order to correctly free the result.
//
static char* generate_class_cast_message(JavaThread* thr, Klass* caster_klass);
// Fill in the "X cannot be cast to a Y" message for ClassCastException
//
// @param caster_klass the class of the object we are casting
// @param target_klass the target klass attempt
// @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(Klass* caster_klass, Klass* target_klass, Symbol* target_klass_name = NULL);
// 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);
static bool handle_ic_miss_helper_internal(Handle receiver, CompiledMethod* caller_nm, const frame& caller_frame,
methodHandle callee_method, Bytecodes::Code bc, CallInfo& call_info,
bool& needs_ic_stub_refill, TRAPS);
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 Method* extract_attached_method(vframeStream& vfst);
static address clean_virtual_call_entry();
static address clean_opt_virtual_call_entry();
static address clean_static_call_entry();
#if defined(X86) && defined(COMPILER1)
// For Object.hashCode, System.identityHashCode try to pull hashCode from object header if available.
static void inline_check_hashcode_from_object_header(MacroAssembler* masm, const methodHandle& method, Register obj_reg, Register result);
#endif // X86 && COMPILER1
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(const methodHandle& method,
const BasicType* sig_bt,
const VMRegPair* regs) NOT_DEBUG_RETURN;
// Ditto except for calling C
//
// C argument in register AND stack slot.
// Some architectures require that an argument must be passed in a register
// AND in a stack slot. These architectures provide a second VMRegPair array
// to be filled by the c_calling_convention method. On other architectures,
// NULL is being passed as the second VMRegPair array, so arguments are either
// passed in a register OR in a stack slot.
static int c_calling_convention(const BasicType *sig_bt, VMRegPair *regs, VMRegPair *regs2,
int total_args_passed);
static size_t trampoline_size();
static void generate_trampoline(MacroAssembler *masm, address destination);
// 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 its 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.
// Additionally 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);
static void gen_i2c_adapter(MacroAssembler *_masm,
int total_args_passed,
int comp_args_on_stack,
const BasicType *sig_bt,
const VMRegPair *regs);
// 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,
const methodHandle& method,
int compile_id,
BasicType* sig_bt,
VMRegPair* regs,
BasicType ret_type,
address critical_entry);
// Block before entering a JNI critical method
static void block_for_jni_critical(JavaThread* thread);
// Pin/Unpin object
static oopDesc* pin_object(JavaThread* thread, oopDesc* obj);
static void unpin_object(JavaThread* thread, oopDesc* obj);
// 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);
static bool should_fixup_call_destination(address destination, address entry_point, address caller_pc, Method* moop, CodeBlob* cb);
// 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, JavaThread* thread);
// 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);
static address handle_unsafe_access(JavaThread* thread, address next_pc);
#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 _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 contiguous.
// 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 official 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;
address _c2i_no_clinit_check_entry;
#ifdef ASSERT
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