compiledIC.cpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#include"code/codeBehaviours.hpp"
#include"code/codeCache.hpp"
#include"code/compiledIC.hpp"
#include"code/nmethod.hpp"
#include"code/vtableStubs.hpp"
#include"memory/resourceArea.hpp"
#include"memory/universe.hpp"
#include"oops/compressedKlass.hpp"
#include"oops/klass.inline.hpp"
#include"oops/method.inline.hpp"
#include"runtime/atomic.hpp"
#include"runtime/continuationEntry.hpp"
#include"runtime/handles.inline.hpp"
#include"runtime/interfaceSupport.inline.hpp"
#include"runtime/sharedRuntime.hpp"
#include"sanitizers/leak.hpp"


// Every time a compiled IC is changed or its type is being accessed,
// either the CompiledIC_lock must be set or we must be at a safe point.

CompiledICLocker::CompiledICLocker(nmethod* method)
 : _method(method),
 _behaviour(CompiledICProtectionBehaviour::current()),
 _locked(_behaviour->lock(_method)) {
}

CompiledICLocker::~CompiledICLocker() {
if (_locked) {
 _behaviour->unlock(_method);
 }
}

boolCompiledICLocker::is_safe(nmethod* method) {
returnCompiledICProtectionBehaviour::current()->is_safe(method);
}

boolCompiledICLocker::is_safe(address code) {
 CodeBlob* cb = CodeCache::find_blob(code);
assert(cb != nullptr && cb->is_nmethod(), "must be compiled");
 nmethod* nm = cb->as_nmethod();
returnCompiledICProtectionBehaviour::current()->is_safe(nm);
}

CompiledICData::CompiledICData()
 : _speculated_method(),
 _speculated_klass(),
 _itable_defc_klass(),
 _itable_refc_klass(),
 _is_initialized() {}

// Inline cache callsite info is initialized once the first time it is resolved
voidCompiledICData::initialize(CallInfo* call_info, Klass* receiver_klass) {
 _speculated_method = call_info->selected_method();
if (UseCompressedClassPointers) {
 _speculated_klass = (uintptr_t)CompressedKlassPointers::encode_not_null(receiver_klass);
 } else {
 _speculated_klass = (uintptr_t)receiver_klass;
 }
if (call_info->call_kind() == CallInfo::itable_call) {
assert(call_info->resolved_method() != nullptr, "virtual or interface method must be found");
 _itable_defc_klass = call_info->resolved_method()->method_holder();
 _itable_refc_klass = call_info->resolved_klass();
 }
 _is_initialized = true;
}

boolCompiledICData::is_speculated_klass_unloaded() const {
returnis_initialized() && _speculated_klass == 0;
}

voidCompiledICData::clean_metadata() {
if (!is_initialized() || is_speculated_klass_unloaded()) {
return;
 }

// GC cleaning doesn't need to change the state of the inline cache,
// only nuke stale speculated metadata if it gets unloaded. If the
// inline cache is monomorphic, the unverified entries will miss, and
// subsequent miss handlers will upgrade the callsite to megamorphic,
// which makes sense as it obviously is megamorphic then.
if (!speculated_klass()->is_loader_alive()) {
Atomic::store(&_speculated_klass, (uintptr_t)0);
Atomic::store(&_speculated_method, (Method*)nullptr);
 }

assert(_speculated_method == nullptr || _speculated_method->method_holder()->is_loader_alive(),
"Speculated method is not unloaded despite class being unloaded");
}

voidCompiledICData::metadata_do(MetadataClosure* cl) {
if (!is_initialized()) {
return;
 }

if (!is_speculated_klass_unloaded()) {
 cl->do_metadata(_speculated_method);
 cl->do_metadata(speculated_klass());
 }
if (_itable_refc_klass != nullptr) {
 cl->do_metadata(_itable_refc_klass);
 }
if (_itable_defc_klass != nullptr) {
 cl->do_metadata(_itable_defc_klass);
 }
}

Klass* CompiledICData::speculated_klass() const {
if (is_speculated_klass_unloaded()) {
returnnullptr;
 }

if (UseCompressedClassPointers) {
returnCompressedKlassPointers::decode_not_null((narrowKlass)_speculated_klass);
 } else {
return (Klass*)_speculated_klass;
 }
}

//-----------------------------------------------------------------------------
// High-level access to an inline cache. Guaranteed to be MT-safe.

CompiledICData* CompiledIC::data() const {
return _data;
}

CompiledICData* data_from_reloc_iter(RelocIterator* iter) {
assert(iter->type() == relocInfo::virtual_call_type, "wrong reloc. info");

 virtual_call_Relocation* r = iter->virtual_call_reloc();
 NativeMovConstReg* value = nativeMovConstReg_at(r->cached_value());

return (CompiledICData*)value->data();
}

CompiledIC::CompiledIC(RelocIterator* iter)
 : _method(iter->code()),
 _data(data_from_reloc_iter(iter)),
 _call(nativeCall_at(iter->addr()))
{
assert(_method != nullptr, "must pass compiled method");
assert(_method->contains(iter->addr()), "must be in compiled method");
assert(CompiledICLocker::is_safe(_method), "mt unsafe call");
}

CompiledIC* CompiledIC_before(nmethod* nm, address return_addr) {
 address call_site = nativeCall_before(return_addr)->instruction_address();
returnCompiledIC_at(nm, call_site);
}

CompiledIC* CompiledIC_at(nmethod* nm, address call_site) {
 RelocIterator iter(nm, call_site, call_site + 1);
 iter.next();
returnCompiledIC_at(&iter);
}

CompiledIC* CompiledIC_at(Relocation* call_reloc) {
 address call_site = call_reloc->addr();
 nmethod* nm = CodeCache::find_blob(call_reloc->addr())->as_nmethod();
returnCompiledIC_at(nm, call_site);
}

CompiledIC* CompiledIC_at(RelocIterator* reloc_iter) {
 CompiledIC* c_ic = newCompiledIC(reloc_iter);
 c_ic->verify();
return c_ic;
}

voidCompiledIC::ensure_initialized(CallInfo* call_info, Klass* receiver_klass) {
if (!_data->is_initialized()) {
 _data->initialize(call_info, receiver_klass);
 }
}

voidCompiledIC::set_to_clean() {
log_debug(inlinecache)("IC@" INTPTR_FORMAT ": set to clean", p2i(_call->instruction_address()));
 _call->set_destination_mt_safe(SharedRuntime::get_resolve_virtual_call_stub());
}

voidCompiledIC::set_to_monomorphic() {
assert(data()->is_initialized(), "must be initialized");
 Method* method = data()->speculated_method();
 nmethod* code = method->code();
 address entry;
bool to_compiled = code != nullptr && code->is_in_use() && !code->is_unloading();

if (to_compiled) {
 entry = code->entry_point();
 } else {
 entry = method->get_c2i_unverified_entry();
 }

log_trace(inlinecache)("IC@" INTPTR_FORMAT ": monomorphic to %s: %s",
p2i(_call->instruction_address()),
 to_compiled ? "compiled" : "interpreter",
 method->print_value_string());

 _call->set_destination_mt_safe(entry);
}

voidCompiledIC::set_to_megamorphic(CallInfo* call_info) {
assert(data()->is_initialized(), "must be initialized");

 address entry;
if (call_info->call_kind() == CallInfo::direct_call) {
// C1 sometimes compiles a callsite before the target method is loaded, resulting in
// dynamically bound callsites that should really be statically bound. However, the
// target method might not have a vtable or itable. We just wait for better code to arrive
return;
 } elseif (call_info->call_kind() == CallInfo::itable_call) {
int itable_index = call_info->itable_index();
 entry = VtableStubs::find_itable_stub(itable_index);
if (entry == nullptr) {
return;
 }
#ifdef ASSERT
assert(call_info->resolved_method() != nullptr, "virtual or interface method must be found");
intindex = call_info->resolved_method()->itable_index();
assert(index == itable_index, "CallInfo pre-computes this");
 InstanceKlass* k = call_info->resolved_method()->method_holder();
assert(k->verify_itable_index(itable_index), "sanity check");
#endif//ASSERT
 } else {
assert(call_info->call_kind() == CallInfo::vtable_call, "what else?");
// Can be different than selected_method->vtable_index(), due to package-private etc.
int vtable_index = call_info->vtable_index();
assert(call_info->resolved_klass()->verify_vtable_index(vtable_index), "sanity check");
 entry = VtableStubs::find_vtable_stub(vtable_index);
if (entry == nullptr) {
return;
 }
 }

assert(call_info->selected_method() != nullptr, "virtual or interface method must be found");
log_trace(inlinecache)("IC@" INTPTR_FORMAT ": to megamorphic %s entry: " INTPTR_FORMAT,
p2i(_call->instruction_address()), call_info->selected_method()->print_value_string(), p2i(entry));

 _call->set_destination_mt_safe(entry);
assert(is_megamorphic(), "sanity check");
}

voidCompiledIC::update(CallInfo* call_info, Klass* receiver_klass) {
// If this is the first time we fix the inline cache, we ensure it's initialized
ensure_initialized(call_info, receiver_klass);

if (is_megamorphic()) {
// Terminal state for the inline cache
return;
 }

if (is_speculated_klass(receiver_klass)) {
// If the speculated class matches the receiver klass, we can speculate that will
// continue to be the case with a monomorphic inline cache
set_to_monomorphic();
 } else {
// If the dynamic type speculation fails, we try to transform to a megamorphic state
// for the inline cache using stubs to dispatch in tables
set_to_megamorphic(call_info);
 }
}

boolCompiledIC::is_clean() const {
returndestination() == SharedRuntime::get_resolve_virtual_call_stub();
}

boolCompiledIC::is_monomorphic() const {
return !is_clean() && !is_megamorphic();
}

boolCompiledIC::is_megamorphic() const {
returnVtableStubs::entry_point(destination()) != nullptr;
}

boolCompiledIC::is_speculated_klass(Klass* receiver_klass) {
returndata()->speculated_klass() == receiver_klass;
}

// GC support
voidCompiledIC::clean_metadata() {
data()->clean_metadata();
}

voidCompiledIC::metadata_do(MetadataClosure* cl) {
data()->metadata_do(cl);
}

#ifndef PRODUCT
voidCompiledIC::print() {
 tty->print("Inline cache at " INTPTR_FORMAT ", calling " INTPTR_FORMAT " cached_value " INTPTR_FORMAT,
p2i(instruction_address()), p2i(destination()), p2i(data()));
 tty->cr();
}

voidCompiledIC::verify() {
 _call->verify();
}
#endif

// ----------------------------------------------------------------------------

voidCompiledDirectCall::set_to_clean() {
// in_use is unused but needed to match template function in nmethod
assert(CompiledICLocker::is_safe(instruction_address()), "mt unsafe call");
// Reset call site
 RelocIterator iter((nmethod*)nullptr, instruction_address(), instruction_address() + 1);
while (iter.next()) {
switch(iter.type()) {
case relocInfo::static_call_type:
 _call->set_destination_mt_safe(SharedRuntime::get_resolve_static_call_stub());
break;
case relocInfo::opt_virtual_call_type:
 _call->set_destination_mt_safe(SharedRuntime::get_resolve_opt_virtual_call_stub());
break;
default:
ShouldNotReachHere();
 }
 }
assert(is_clean(), "should be clean after cleaning");

log_debug(inlinecache)("DC@" INTPTR_FORMAT ": set to clean", p2i(_call->instruction_address()));
}

voidCompiledDirectCall::set(const methodHandle& callee_method) {
 nmethod* code = callee_method->code();
 nmethod* caller = CodeCache::find_nmethod(instruction_address());
assert(caller != nullptr, "did not find caller nmethod");

bool to_interp_cont_enter = caller->method()->is_continuation_enter_intrinsic() &&
ContinuationEntry::is_interpreted_call(instruction_address());

bool to_compiled = !to_interp_cont_enter && code != nullptr && code->is_in_use() && !code->is_unloading();

if (to_compiled) {
 _call->set_destination_mt_safe(code->verified_entry_point());
assert(is_call_to_compiled(), "should be compiled after set to compiled");
 } else {
// Patch call site to C2I adapter if code is deoptimized or unloaded.
// We also need to patch the static call stub to set the rmethod register
// to the callee_method so the c2i adapter knows how to build the frame
set_to_interpreted(callee_method, callee_method->get_c2i_entry());
assert(is_call_to_interpreted(), "should be interpreted after set to interpreted");
 }

log_trace(inlinecache)("DC@" INTPTR_FORMAT ": set to %s: %s: " INTPTR_FORMAT,
p2i(_call->instruction_address()),
 to_compiled ? "compiled" : "interpreter",
 callee_method->print_value_string(),
p2i(_call->destination()));
}

boolCompiledDirectCall::is_clean() const {
returndestination() == SharedRuntime::get_resolve_static_call_stub() ||
destination() == SharedRuntime::get_resolve_opt_virtual_call_stub();
}

boolCompiledDirectCall::is_call_to_interpreted() const {
// It is a call to interpreted, if it calls to a stub. Hence, the destination
// must be in the stub part of the nmethod that contains the call
 nmethod* nm = CodeCache::find_nmethod(instruction_address());
assert(nm != nullptr, "did not find nmethod");
return nm->stub_contains(destination());
}

boolCompiledDirectCall::is_call_to_compiled() const {
 nmethod* caller = CodeCache::find_nmethod(instruction_address());
assert(caller != nullptr, "did not find caller nmethod");
 CodeBlob* dest_cb = CodeCache::find_blob(destination());
return !caller->stub_contains(destination()) && dest_cb->is_nmethod();
}

address CompiledDirectCall::find_stub_for(address instruction) {
// Find reloc. information containing this call-site
 RelocIterator iter((nmethod*)nullptr, instruction);
while (iter.next()) {
if (iter.addr() == instruction) {
switch(iter.type()) {
case relocInfo::static_call_type:
return iter.static_call_reloc()->static_stub();
// We check here for opt_virtual_call_type, since we reuse the code
// from the CompiledIC implementation
case relocInfo::opt_virtual_call_type:
return iter.opt_virtual_call_reloc()->static_stub();
default:
ShouldNotReachHere();
 }
 }
 }
returnnullptr;
}

address CompiledDirectCall::find_stub() {
returnfind_stub_for(instruction_address());
}

#ifndef PRODUCT
voidCompiledDirectCall::print() {
 tty->print("direct call at " INTPTR_FORMAT " to " INTPTR_FORMAT " -> ", p2i(instruction_address()), p2i(destination()));
if (is_clean()) {
 tty->print("clean");
 } elseif (is_call_to_compiled()) {
 tty->print("compiled");
 } elseif (is_call_to_interpreted()) {
 tty->print("interpreted");
 }
 tty->cr();
}

voidCompiledDirectCall::verify_mt_safe(const methodHandle& callee, address entry,
 NativeMovConstReg* method_holder,
 NativeJump* jump) {
 _call->verify();
// A generated lambda form might be deleted from the Lambdaform
// cache in MethodTypeForm. If a jit compiled lambdaform method
// becomes not entrant and the cache access returns null, the new
// resolve will lead to a new generated LambdaForm.
 Method* old_method = reinterpret_cast<Method*>(method_holder->data());
assert(old_method == nullptr || old_method == callee() ||
 callee->is_compiled_lambda_form() ||
 !old_method->method_holder()->is_loader_alive() ||
 old_method->is_old(), // may be race patching deoptimized nmethod due to redefinition.
"a) MT-unsafe modification of inline cache");

 address destination = jump->jump_destination();
assert(destination == (address)-1 || destination == entry
 || old_method == nullptr || !old_method->method_holder()->is_loader_alive() // may have a race due to class unloading.
 || old_method->is_old(), // may be race patching deoptimized nmethod due to redefinition.
"b) MT-unsafe modification of inline cache");
}
#endif