/* * Copyright (c) 1997, 2020, 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. *
*/
void* VtableStub::operatornew(size_t size, int code_size) throw() {
assert_lock_strong(VtableStubs_lock);
assert(size == sizeof(VtableStub), "mismatched size"); // compute real VtableStub size (rounded to nearest word) constint real_size = align_up(code_size + (int)sizeof(VtableStub), wordSize); // malloc them in chunks to minimize header overhead constint chunk_factor = 32; if (_chunk == NULL || _chunk + real_size > _chunk_end) { constint bytes = chunk_factor * real_size + pd_code_alignment();
// There is a dependency on the name of the blob in src/share/vm/prims/jvmtiCodeBlobEvents.cpp // If changing the name, update the other file accordingly.
VtableBlob* blob = VtableBlob::create("vtable chunks", bytes); if (blob == NULL) { return NULL;
}
_chunk = blob->content_begin();
_chunk_end = _chunk + bytes;
Forte::register_stub("vtable stub", _chunk, _chunk_end);
align_chunk();
}
assert(_chunk + real_size <= _chunk_end, "bad allocation"); void* res = _chunk;
_chunk += real_size;
align_chunk(); return res;
}
// ----------------------------------------------------------------------------------------- // Implementation of VtableStubs // // For each hash value there's a linked list of vtable stubs (with that // hash value). Each list is anchored in a little hash _table, indexed // by that hash value.
VtableStub* VtableStubs::_table[VtableStubs::N]; int VtableStubs::_number_of_vtable_stubs = 0; int VtableStubs::_vtab_stub_size = 0; int VtableStubs::_itab_stub_size = 0;
#ifdefined(PRODUCT) // These values are good for the PRODUCT case (no tracing). staticconstint first_vtableStub_size = 64; staticconstint first_itableStub_size = 256; #else // These values are good for the non-PRODUCT case (when tracing can be switched on). // To find out, run test workload with // -Xlog:vtablestubs=Trace -XX:+CountCompiledCalls -XX:+DebugVtables // and use the reported "estimate" value. // Here is a list of observed worst-case values: // vtable itable // aarch64: 460 324 // arm: ? ? // ppc (linux, BE): 404 288 // ppc (linux, LE): 356 276 // ppc (AIX): 416 296 // s390x: 408 256 // Solaris-sparc: 792 348 // x86 (Linux): 670 309 // x86 (MacOS): 682 321 staticconstint first_vtableStub_size = 1024; staticconstint first_itableStub_size = 512; #endif
void VtableStubs::initialize() {
VtableStub::_receiver_location = SharedRuntime::name_for_receiver();
{
MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
assert(_number_of_vtable_stubs == 0, "potential performance bug: VtableStubs initialized more than once");
assert(is_power_of_2(int(N)), "N must be a power of 2"); for (int i = 0; i < N; i++) {
_table[i] = NULL;
}
}
}
// After the first vtable/itable stub is generated, we have a much // better estimate for the stub size. Remember/update this // estimate after some sanity checks.
check_and_set_size_limit(is_vtable_stub, masm->offset(), slop_bytes);
s->set_exception_points(npe_addr, ame_addr);
}
address VtableStubs::find_stub(bool is_vtable_stub, int vtable_index) {
assert(vtable_index >= 0, "must be positive");
VtableStub* s;
{
MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
s = lookup(is_vtable_stub, vtable_index); if (s == NULL) { if (is_vtable_stub) {
s = create_vtable_stub(vtable_index);
} else {
s = create_itable_stub(vtable_index);
}
// Creation of vtable or itable can fail if there is not enough free space in the code cache. if (s == NULL) { return NULL;
}
enter(is_vtable_stub, vtable_index, s); if (PrintAdapterHandlers) {
tty->print_cr("Decoding VtableStub %s[%d]@" INTX_FORMAT,
is_vtable_stub? "vtbl": "itbl", vtable_index, p2i(VtableStub::receiver_location()));
Disassembler::decode(s->code_begin(), s->code_end());
} // Notify JVMTI about this stub. The event will be recorded by the enclosing // JvmtiDynamicCodeEventCollector and posted when this thread has released // all locks. Only post this event if a new state is not required. Creating a new state would // cause a safepoint and the caller of this code has a NoSafepointVerifier. if (JvmtiExport::should_post_dynamic_code_generated()) {
JvmtiExport::post_dynamic_code_generated_while_holding_locks(is_vtable_stub? "vtable stub": "itable stub",
s->code_begin(), s->code_end());
}
}
} return s->entry_point();
}
inline uint VtableStubs::hash(bool is_vtable_stub, int vtable_index){ // Assumption: receiver_location < 4 in most cases. int hash = ((vtable_index << 2) ^ VtableStub::receiver_location()->value()) + vtable_index; return (is_vtable_stub ? ~hash : hash) & mask;
}
VtableStub* VtableStubs::lookup(bool is_vtable_stub, int vtable_index) {
assert_lock_strong(VtableStubs_lock); unsigned hash = VtableStubs::hash(is_vtable_stub, vtable_index);
VtableStub* s = _table[hash]; while( s && !s->matches(is_vtable_stub, vtable_index)) s = s->next(); return s;
}
void VtableStubs::enter(bool is_vtable_stub, int vtable_index, VtableStub* s) {
assert_lock_strong(VtableStubs_lock);
assert(s->matches(is_vtable_stub, vtable_index), "bad vtable stub"); unsignedint h = VtableStubs::hash(is_vtable_stub, vtable_index); // enter s at the beginning of the corresponding list
s->set_next(_table[h]);
_table[h] = s;
_number_of_vtable_stubs++;
}
VtableStub* VtableStubs::entry_point(address pc) {
MutexLocker ml(VtableStubs_lock, Mutex::_no_safepoint_check_flag);
VtableStub* stub = (VtableStub*)(pc - VtableStub::entry_offset());
uint hash = VtableStubs::hash(stub->is_vtable_stub(), stub->index());
VtableStub* s; for (s = _table[hash]; s != NULL && s != stub; s = s->next()) {} return (s == stub) ? s : NULL;
}
bool VtableStubs::contains(address pc) { // simple solution for now - we may want to use // a faster way if this function is called often return stub_containing(pc) != NULL;
}
VtableStub* VtableStubs::stub_containing(address pc) { // Note: No locking needed since any change to the data structure // happens with an atomic store into it (we don't care about // consistency with the _number_of_vtable_stubs counter). for (int i = 0; i < N; i++) { for (VtableStub* s = _table[i]; s != NULL; s = s->next()) { if (s->contains(pc)) return s;
}
} return NULL;
}
void VtableStubs::vtable_stub_do(void f(VtableStub*)) { for (int i = 0; i < N; i++) { for (VtableStub* s = _table[i]; s != NULL; s = s->next()) {
f(s);
}
}
}
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