Mercurial > hg > graal-jvmci-8
view src/cpu/x86/vm/vtableStubs_x86_32.cpp @ 3249:e1162778c1c8
7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes
author | johnc |
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date | Thu, 07 Apr 2011 09:53:20 -0700 |
parents | f95d63e2154a |
children | 1d7922586cf6 |
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/* * Copyright (c) 1997, 2010, 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/assembler.hpp" #include "assembler_x86.inline.hpp" #include "code/vtableStubs.hpp" #include "interp_masm_x86_32.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); 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())); // compute entry offset (in words) int entry_offset = instanceKlass::vtable_start_offset() + vtable_index*vtableEntry::size(); #ifndef PRODUCT if (DebugVtables) { Label L; // check offset vs vtable length __ cmpl(Address(rax, instanceKlass::vtable_length_offset()*wordSize), 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 methodOop and target address __ movptr(method, Address(rax, entry_offset*wordSize + vtableEntry::method_offset_in_bytes())); if (DebugVtables) { Label L; __ cmpptr(method, (int32_t)NULL_WORD); __ jcc(Assembler::equal, L); __ cmpptr(Address(method, methodOopDesc::from_compiled_offset()), (int32_t)NULL_WORD); __ jcc(Assembler::notZero, L); __ stop("Vtable entry is NULL"); __ bind(L); } // rax,: receiver klass // method (rbx): methodOop // rcx: receiver address ame_addr = __ pc(); __ jmp( Address(method, methodOopDesc::from_compiled_offset())); masm->flush(); if (PrintMiscellaneous && (WizardMode || Verbose)) { tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d", vtable_index, 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); 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 methodOop 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): methodOop // rcx: receiver #ifdef ASSERT if (DebugVtables) { Label L1; __ cmpptr(method, (int32_t)NULL_WORD); __ jcc(Assembler::equal, L1); __ cmpptr(Address(method, methodOopDesc::from_compiled_offset()), (int32_t)NULL_WORD); __ jcc(Assembler::notZero, L1); __ stop("methodOop is null"); __ bind(L1); } #endif // ASSERT address ame_addr = __ pc(); __ jmp(Address(method, methodOopDesc::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, 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; }