/* * Copyright (c) 1997, 2014, 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. * */ #include "precompiled.hpp" #include "asm/macroAssembler.hpp" #include "code/vtableStubs.hpp" #include "interp_masm_x86.hpp" #include "memory/resourceArea.hpp" #include "oops/instanceKlass.hpp" #include "oops/klassVtable.hpp" #include "runtime/sharedRuntime.hpp" #include "vmreg_x86.inline.hpp" #ifdef COMPILER2 #include "opto/runtime.hpp" #endif // machine-dependent part of VtableStubs: create VtableStub of correct size and // initialize its code #define __ masm-> #ifndef PRODUCT extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index); #endif // These stubs are used by the compiler only. // Argument registers, which must be preserved: // rcx - receiver (always first argument) // rdx - second argument (if any) // Other registers that might be usable: // rax - inline cache register (is interface for itable stub) // rbx - method (used when calling out to interpreter) // Available now, but may become callee-save at some point: // rsi, rdi // Note that rax and rdx are also used for return values. // VtableStub* VtableStubs::create_vtable_stub(int vtable_index) { const int i486_code_length = VtableStub::pd_code_size_limit(true); VtableStub* s = new(i486_code_length) VtableStub(true, vtable_index); // Can be NULL if there is no free space in the code cache. if (s == NULL) { return NULL; } ResourceMark rm; CodeBuffer cb(s->entry_point(), i486_code_length); MacroAssembler* masm = new MacroAssembler(&cb); #ifndef PRODUCT if (CountCompiledCalls) { __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); } #endif /* PRODUCT */ // get receiver (need to skip return address on top of stack) assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx"); // get receiver klass address npe_addr = __ pc(); __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes())); #ifndef PRODUCT if (DebugVtables) { Label L; // check offset vs vtable length __ cmpl(Address(rax, InstanceKlass::vtable_length_offset()), vtable_index*vtableEntry::size()); __ jcc(Assembler::greater, L); __ movl(rbx, vtable_index); __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx); __ bind(L); } #endif // PRODUCT const Register method = rbx; // load Method* and target address __ lookup_virtual_method(rax, vtable_index, method); if (DebugVtables) { Label L; __ cmpptr(method, (int32_t)NULL_WORD); __ jcc(Assembler::equal, L); __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); __ jcc(Assembler::notZero, L); __ stop("Vtable entry is NULL"); __ bind(L); } // rax,: receiver klass // method (rbx): Method* // rcx: receiver address ame_addr = __ pc(); __ jmp( Address(method, Method::from_compiled_offset())); masm->flush(); if (PrintMiscellaneous && (WizardMode || Verbose)) { tty->print_cr("vtable #%d at " PTR_FORMAT "[%d] left over: %d", vtable_index, p2i(s->entry_point()), (int)(s->code_end() - s->entry_point()), (int)(s->code_end() - __ pc())); } guarantee(__ pc() <= s->code_end(), "overflowed buffer"); // shut the door on sizing bugs int slop = 3; // 32-bit offset is this much larger than an 8-bit one assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); s->set_exception_points(npe_addr, ame_addr); return s; } VtableStub* VtableStubs::create_itable_stub(int itable_index) { // Note well: pd_code_size_limit is the absolute minimum we can get away with. If you // add code here, bump the code stub size returned by pd_code_size_limit! const int i486_code_length = VtableStub::pd_code_size_limit(false); VtableStub* s = new(i486_code_length) VtableStub(false, itable_index); // Can be NULL if there is no free space in the code cache. if (s == NULL) { return NULL; } ResourceMark rm; CodeBuffer cb(s->entry_point(), i486_code_length); MacroAssembler* masm = new MacroAssembler(&cb); // Entry arguments: // rax,: Interface // rcx: Receiver #ifndef PRODUCT if (CountCompiledCalls) { __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); } #endif /* PRODUCT */ // get receiver (need to skip return address on top of stack) assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx"); // get receiver klass (also an implicit null-check) address npe_addr = __ pc(); __ movptr(rsi, Address(rcx, oopDesc::klass_offset_in_bytes())); // Most registers are in use; we'll use rax, rbx, rsi, rdi // (If we need to make rsi, rdi callee-save, do a push/pop here.) const Register method = rbx; Label throw_icce; // Get Method* and entrypoint for compiler __ lookup_interface_method(// inputs: rec. class, interface, itable index rsi, rax, itable_index, // outputs: method, scan temp. reg method, rdi, throw_icce); // method (rbx): Method* // rcx: receiver #ifdef ASSERT if (DebugVtables) { Label L1; __ cmpptr(method, (int32_t)NULL_WORD); __ jcc(Assembler::equal, L1); __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); __ jcc(Assembler::notZero, L1); __ stop("Method* is null"); __ bind(L1); } #endif // ASSERT address ame_addr = __ pc(); __ jmp(Address(method, Method::from_compiled_offset())); __ bind(throw_icce); __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry())); masm->flush(); if (PrintMiscellaneous && (WizardMode || Verbose)) { tty->print_cr("itable #%d at " PTR_FORMAT "[%d] left over: %d", itable_index, p2i(s->entry_point()), (int)(s->code_end() - s->entry_point()), (int)(s->code_end() - __ pc())); } guarantee(__ pc() <= s->code_end(), "overflowed buffer"); // shut the door on sizing bugs int slop = 3; // 32-bit offset is this much larger than an 8-bit one assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); s->set_exception_points(npe_addr, ame_addr); return s; } int VtableStub::pd_code_size_limit(bool is_vtable_stub) { if (is_vtable_stub) { // Vtable stub size return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0); } else { // Itable stub size return (DebugVtables ? 256 : 66) + (CountCompiledCalls ? 6 : 0); } // In order to tune these parameters, run the JVM with VM options // +PrintMiscellaneous and +WizardMode to see information about // actual itable stubs. Look for lines like this: // itable #1 at 0x5551212[65] left over: 3 // Reduce the constants so that the "left over" number is >=3 // for the common cases. // Do not aim at a left-over number of zero, because a // large vtable or itable index (> 16) will require a 32-bit // immediate displacement instead of an 8-bit one. // // The JVM98 app. _202_jess has a megamorphic interface call. // The itable code looks like this: // Decoding VtableStub itbl[1]@1 // mov 0x4(%ecx),%esi // mov 0xe8(%esi),%edi // lea 0x130(%esi,%edi,4),%edi // add $0x7,%edi // and $0xfffffff8,%edi // lea 0x4(%esi),%esi // mov (%edi),%ebx // cmp %ebx,%eax // je success // loop: // test %ebx,%ebx // je throw_icce // add $0x8,%edi // mov (%edi),%ebx // cmp %ebx,%eax // jne loop // success: // mov 0x4(%edi),%edi // mov (%esi,%edi,1),%ebx // jmp *0x44(%ebx) // throw_icce: // jmp throw_ICCE_entry } int VtableStub::pd_code_alignment() { return wordSize; }