JDK14/Java14源码在线阅读
/*
* Copyright (c) 2005, 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "ci/ciArrayKlass.hpp"
#include "ci/ciEnv.hpp"
#include "ci/ciKlass.hpp"
#include "ci/ciMethod.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "code/dependencies.hpp"
#include "compiler/compileLog.hpp"
#include "compiler/compileBroker.hpp"
#include "compiler/compileTask.hpp"
#include "memory/resourceArea.hpp"
#include "oops/klass.hpp"
#include "oops/oop.inline.hpp"
#include "oops/objArrayKlass.hpp"
#include "runtime/flags/flagSetting.hpp"
#include "runtime/handles.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/jniHandles.inline.hpp"
#include "runtime/thread.inline.hpp"
#include "utilities/copy.hpp"
#ifdef ASSERT
static bool must_be_in_vm() {
Thread* thread = Thread::current();
if (thread->is_Java_thread())
return ((JavaThread*)thread)->thread_state() == _thread_in_vm;
else
return true; //something like this: thread->is_VM_thread();
}
#endif //ASSERT
void Dependencies::initialize(ciEnv* env) {
Arena* arena = env->arena();
_oop_recorder = env->oop_recorder();
_log = env->log();
_dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
#if INCLUDE_JVMCI
_using_dep_values = false;
#endif
DEBUG_ONLY(_deps[end_marker] = NULL);
for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
_deps[i] = new(arena) GrowableArray<ciBaseObject*>(arena, 10, 0, 0);
}
_content_bytes = NULL;
_size_in_bytes = (size_t)-1;
assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
}
void Dependencies::assert_evol_method(ciMethod* m) {
assert_common_1(evol_method, m);
}
void Dependencies::assert_leaf_type(ciKlass* ctxk) {
if (ctxk->is_array_klass()) {
// As a special case, support this assertion on an array type,
// which reduces to an assertion on its element type.
// Note that this cannot be done with assertions that
// relate to concreteness or abstractness.
ciType* elemt = ctxk->as_array_klass()->base_element_type();
if (!elemt->is_instance_klass()) return; // Ex: int[][]
ctxk = elemt->as_instance_klass();
//if (ctxk->is_final()) return; // Ex: String[][]
}
check_ctxk(ctxk);
assert_common_1(leaf_type, ctxk);
}
void Dependencies::assert_abstract_with_unique_concrete_subtype(ciKlass* ctxk, ciKlass* conck) {
check_ctxk_abstract(ctxk);
assert_common_2(abstract_with_unique_concrete_subtype, ctxk, conck);
}
void Dependencies::assert_abstract_with_no_concrete_subtype(ciKlass* ctxk) {
check_ctxk_abstract(ctxk);
assert_common_1(abstract_with_no_concrete_subtype, ctxk);
}
void Dependencies::assert_concrete_with_no_concrete_subtype(ciKlass* ctxk) {
check_ctxk_concrete(ctxk);
assert_common_1(concrete_with_no_concrete_subtype, ctxk);
}
void Dependencies::assert_unique_concrete_method(ciKlass* ctxk, ciMethod* uniqm) {
check_ctxk(ctxk);
check_unique_method(ctxk, uniqm);
assert_common_2(unique_concrete_method, ctxk, uniqm);
}
void Dependencies::assert_abstract_with_exclusive_concrete_subtypes(ciKlass* ctxk, ciKlass* k1, ciKlass* k2) {
check_ctxk(ctxk);
assert_common_3(abstract_with_exclusive_concrete_subtypes_2, ctxk, k1, k2);
}
void Dependencies::assert_exclusive_concrete_methods(ciKlass* ctxk, ciMethod* m1, ciMethod* m2) {
check_ctxk(ctxk);
assert_common_3(exclusive_concrete_methods_2, ctxk, m1, m2);
}
void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
check_ctxk(ctxk);
assert_common_1(no_finalizable_subclasses, ctxk);
}
void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
assert_common_2(call_site_target_value, call_site, method_handle);
}
#if INCLUDE_JVMCI
Dependencies::Dependencies(Arena* arena, OopRecorder* oop_recorder, CompileLog* log) {
_oop_recorder = oop_recorder;
_log = log;
_dep_seen = new(arena) GrowableArray<int>(arena, 500, 0, 0);
_using_dep_values = true;
DEBUG_ONLY(_dep_values[end_marker] = NULL);
for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
_dep_values[i] = new(arena) GrowableArray<DepValue>(arena, 10, 0, DepValue());
}
_content_bytes = NULL;
_size_in_bytes = (size_t)-1;
assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT), "sanity");
}
void Dependencies::assert_evol_method(Method* m) {
assert_common_1(evol_method, DepValue(_oop_recorder, m));
}
void Dependencies::assert_has_no_finalizable_subclasses(Klass* ctxk) {
check_ctxk(ctxk);
assert_common_1(no_finalizable_subclasses, DepValue(_oop_recorder, ctxk));
}
void Dependencies::assert_leaf_type(Klass* ctxk) {
if (ctxk->is_array_klass()) {
// As a special case, support this assertion on an array type,
// which reduces to an assertion on its element type.
// Note that this cannot be done with assertions that
// relate to concreteness or abstractness.
BasicType elemt = ArrayKlass::cast(ctxk)->element_type();
if (is_java_primitive(elemt)) return; // Ex: int[][]
ctxk = ObjArrayKlass::cast(ctxk)->bottom_klass();
//if (ctxk->is_final()) return; // Ex: String[][]
}
check_ctxk(ctxk);
assert_common_1(leaf_type, DepValue(_oop_recorder, ctxk));
}
void Dependencies::assert_abstract_with_unique_concrete_subtype(Klass* ctxk, Klass* conck) {
check_ctxk_abstract(ctxk);
DepValue ctxk_dv(_oop_recorder, ctxk);
DepValue conck_dv(_oop_recorder, conck, &ctxk_dv);
assert_common_2(abstract_with_unique_concrete_subtype, ctxk_dv, conck_dv);
}
void Dependencies::assert_unique_concrete_method(Klass* ctxk, Method* uniqm) {
check_ctxk(ctxk);
check_unique_method(ctxk, uniqm);
assert_common_2(unique_concrete_method, DepValue(_oop_recorder, ctxk), DepValue(_oop_recorder, uniqm));
}
void Dependencies::assert_call_site_target_value(oop call_site, oop method_handle) {
assert_common_2(call_site_target_value, DepValue(_oop_recorder, JNIHandles::make_local(call_site)), DepValue(_oop_recorder, JNIHandles::make_local(method_handle)));
}
#endif // INCLUDE_JVMCI
// Helper function. If we are adding a new dep. under ctxk2,
// try to find an old dep. under a broader* ctxk1. If there is
//
bool Dependencies::maybe_merge_ctxk(GrowableArray<ciBaseObject*>* deps,
int ctxk_i, ciKlass* ctxk2) {
ciKlass* ctxk1 = deps->at(ctxk_i)->as_metadata()->as_klass();
if (ctxk2->is_subtype_of(ctxk1)) {
return true; // success, and no need to change
} else if (ctxk1->is_subtype_of(ctxk2)) {
// new context class fully subsumes previous one
deps->at_put(ctxk_i, ctxk2);
return true;
} else {
return false;
}
}
void Dependencies::assert_common_1(DepType dept, ciBaseObject* x) {
assert(dep_args(dept) == 1, "sanity");
log_dependency(dept, x);
GrowableArray<ciBaseObject*>* deps = _deps[dept];
// see if the same (or a similar) dep is already recorded
if (note_dep_seen(dept, x)) {
assert(deps->find(x) >= 0, "sanity");
} else {
deps->append(x);
}
}
void Dependencies::assert_common_2(DepType dept,
ciBaseObject* x0, ciBaseObject* x1) {
assert(dep_args(dept) == 2, "sanity");
log_dependency(dept, x0, x1);
GrowableArray<ciBaseObject*>* deps = _deps[dept];
// see if the same (or a similar) dep is already recorded
bool has_ctxk = has_explicit_context_arg(dept);
if (has_ctxk) {
assert(dep_context_arg(dept) == 0, "sanity");
if (note_dep_seen(dept, x1)) {
// look in this bucket for redundant assertions
const int stride = 2;
for (int i = deps->length(); (i -= stride) >= 0; ) {
ciBaseObject* y1 = deps->at(i+1);
if (x1 == y1) { // same subject; check the context
if (maybe_merge_ctxk(deps, i+0, x0->as_metadata()->as_klass())) {
return;
}
}
}
}
} else {
if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
// look in this bucket for redundant assertions
const int stride = 2;
for (int i = deps->length(); (i -= stride) >= 0; ) {
ciBaseObject* y0 = deps->at(i+0);
ciBaseObject* y1 = deps->at(i+1);
if (x0 == y0 && x1 == y1) {
return;
}
}
}
}
// append the assertion in the correct bucket:
deps->append(x0);
deps->append(x1);
}
void Dependencies::assert_common_3(DepType dept,
ciKlass* ctxk, ciBaseObject* x, ciBaseObject* x2) {
assert(dep_context_arg(dept) == 0, "sanity");
assert(dep_args(dept) == 3, "sanity");
log_dependency(dept, ctxk, x, x2);
GrowableArray<ciBaseObject*>* deps = _deps[dept];
// try to normalize an unordered pair:
bool swap = false;
switch (dept) {
case abstract_with_exclusive_concrete_subtypes_2:
swap = (x->ident() > x2->ident() && x->as_metadata()->as_klass() != ctxk);
break;
case exclusive_concrete_methods_2:
swap = (x->ident() > x2->ident() && x->as_metadata()->as_method()->holder() != ctxk);
break;
default:
break;
}
if (swap) { ciBaseObject* t = x; x = x2; x2 = t; }
// see if the same (or a similar) dep is already recorded
if (note_dep_seen(dept, x) && note_dep_seen(dept, x2)) {
// look in this bucket for redundant assertions
const int stride = 3;
for (int i = deps->length(); (i -= stride) >= 0; ) {
ciBaseObject* y = deps->at(i+1);
ciBaseObject* y2 = deps->at(i+2);
if (x == y && x2 == y2) { // same subjects; check the context
if (maybe_merge_ctxk(deps, i+0, ctxk)) {
return;
}
}
}
}
// append the assertion in the correct bucket:
deps->append(ctxk);
deps->append(x);
deps->append(x2);
}
#if INCLUDE_JVMCI
bool Dependencies::maybe_merge_ctxk(GrowableArray<DepValue>* deps,
int ctxk_i, DepValue ctxk2_dv) {
Klass* ctxk1 = deps->at(ctxk_i).as_klass(_oop_recorder);
Klass* ctxk2 = ctxk2_dv.as_klass(_oop_recorder);
if (ctxk2->is_subtype_of(ctxk1)) {
return true; // success, and no need to change
} else if (ctxk1->is_subtype_of(ctxk2)) {
// new context class fully subsumes previous one
deps->at_put(ctxk_i, ctxk2_dv);
return true;
} else {
return false;
}
}
void Dependencies::assert_common_1(DepType dept, DepValue x) {
assert(dep_args(dept) == 1, "sanity");
//log_dependency(dept, x);
GrowableArray<DepValue>* deps = _dep_values[dept];
// see if the same (or a similar) dep is already recorded
if (note_dep_seen(dept, x)) {
assert(deps->find(x) >= 0, "sanity");
} else {
deps->append(x);
}
}
void Dependencies::assert_common_2(DepType dept,
DepValue x0, DepValue x1) {
assert(dep_args(dept) == 2, "sanity");
//log_dependency(dept, x0, x1);
GrowableArray<DepValue>* deps = _dep_values[dept];
// see if the same (or a similar) dep is already recorded
bool has_ctxk = has_explicit_context_arg(dept);
if (has_ctxk) {
assert(dep_context_arg(dept) == 0, "sanity");
if (note_dep_seen(dept, x1)) {
// look in this bucket for redundant assertions
const int stride = 2;
for (int i = deps->length(); (i -= stride) >= 0; ) {
DepValue y1 = deps->at(i+1);
if (x1 == y1) { // same subject; check the context
if (maybe_merge_ctxk(deps, i+0, x0)) {
return;
}
}
}
}
} else {
if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
// look in this bucket for redundant assertions
const int stride = 2;
for (int i = deps->length(); (i -= stride) >= 0; ) {
DepValue y0 = deps->at(i+0);
DepValue y1 = deps->at(i+1);
if (x0 == y0 && x1 == y1) {
return;
}
}
}
}
// append the assertion in the correct bucket:
deps->append(x0);
deps->append(x1);
}
#endif // INCLUDE_JVMCI
/// Support for encoding dependencies into an nmethod:
void Dependencies::copy_to(nmethod* nm) {
address beg = nm->dependencies_begin();
address end = nm->dependencies_end();
guarantee(end - beg >= (ptrdiff_t) size_in_bytes(), "bad sizing");
Copy::disjoint_words((HeapWord*) content_bytes(),
(HeapWord*) beg,
size_in_bytes() / sizeof(HeapWord));
assert(size_in_bytes() % sizeof(HeapWord) == 0, "copy by words");
}
static int sort_dep(ciBaseObject** p1, ciBaseObject** p2, int narg) {
for (int i = 0; i < narg; i++) {
int diff = p1[i]->ident() - p2[i]->ident();
if (diff != 0) return diff;
}
return 0;
}
static int sort_dep_arg_1(ciBaseObject** p1, ciBaseObject** p2)
{ return sort_dep(p1, p2, 1); }
static int sort_dep_arg_2(ciBaseObject** p1, ciBaseObject** p2)
{ return sort_dep(p1, p2, 2); }
static int sort_dep_arg_3(ciBaseObject** p1, ciBaseObject** p2)
{ return sort_dep(p1, p2, 3); }
#if INCLUDE_JVMCI
// metadata deps are sorted before object deps
static int sort_dep_value(Dependencies::DepValue* p1, Dependencies::DepValue* p2, int narg) {
for (int i = 0; i < narg; i++) {
int diff = p1[i].sort_key() - p2[i].sort_key();
if (diff != 0) return diff;
}
return 0;
}
static int sort_dep_value_arg_1(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
{ return sort_dep_value(p1, p2, 1); }
static int sort_dep_value_arg_2(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
{ return sort_dep_value(p1, p2, 2); }
static int sort_dep_value_arg_3(Dependencies::DepValue* p1, Dependencies::DepValue* p2)
{ return sort_dep_value(p1, p2, 3); }
#endif // INCLUDE_JVMCI
void Dependencies::sort_all_deps() {
#if INCLUDE_JVMCI
if (_using_dep_values) {
for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
DepType dept = (DepType)deptv;
GrowableArray<DepValue>* deps = _dep_values[dept];
if (deps->length() <= 1) continue;
switch (dep_args(dept)) {
case 1: deps->sort(sort_dep_value_arg_1, 1); break;
case 2: deps->sort(sort_dep_value_arg_2, 2); break;
case 3: deps->sort(sort_dep_value_arg_3, 3); break;
default: ShouldNotReachHere(); break;
}
}
return;
}
#endif // INCLUDE_JVMCI
for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
DepType dept = (DepType)deptv;
GrowableArray<ciBaseObject*>* deps = _deps[dept];
if (deps->length() <= 1) continue;
switch (dep_args(dept)) {
case 1: deps->sort(sort_dep_arg_1, 1); break;
case 2: deps->sort(sort_dep_arg_2, 2); break;
case 3: deps->sort(sort_dep_arg_3, 3); break;
default: ShouldNotReachHere(); break;
}
}
}
size_t Dependencies::estimate_size_in_bytes() {
size_t est_size = 100;
#if INCLUDE_JVMCI
if (_using_dep_values) {
for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
DepType dept = (DepType)deptv;
GrowableArray<DepValue>* deps = _dep_values[dept];
est_size += deps->length() * 2; // tags and argument(s)
}
return est_size;
}
#endif // INCLUDE_JVMCI
for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
DepType dept = (DepType)deptv;
GrowableArray<ciBaseObject*>* deps = _deps[dept];
est_size += deps->length()*2; // tags and argument(s)
}
return est_size;
}
ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciBaseObject* x) {
switch (dept) {
case abstract_with_exclusive_concrete_subtypes_2:
return x->as_metadata()->as_klass();
case unique_concrete_method:
case exclusive_concrete_methods_2:
return x->as_metadata()->as_method()->holder();
default:
return NULL; // let NULL be NULL
}
}
Klass* Dependencies::ctxk_encoded_as_null(DepType dept, Metadata* x) {
assert(must_be_in_vm(), "raw oops here");
switch (dept) {
case abstract_with_exclusive_concrete_subtypes_2:
assert(x->is_klass(), "sanity");
return (Klass*) x;
case unique_concrete_method:
case exclusive_concrete_methods_2:
assert(x->is_method(), "sanity");
return ((Method*)x)->method_holder();
default:
return NULL; // let NULL be NULL
}
}
void Dependencies::encode_content_bytes() {
sort_all_deps();
// cast is safe, no deps can overflow INT_MAX
CompressedWriteStream bytes((int)estimate_size_in_bytes());
#if INCLUDE_JVMCI
if (_using_dep_values) {
for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
DepType dept = (DepType)deptv;
GrowableArray<DepValue>* deps = _dep_values[dept];
if (deps->length() == 0) continue;
int stride = dep_args(dept);
int ctxkj = dep_context_arg(dept); // -1 if no context arg
assert(stride > 0, "sanity");
for (int i = 0; i < deps->length(); i += stride) {
jbyte code_byte = (jbyte)dept;
int skipj = -1;
if (ctxkj >= 0 && ctxkj+1 < stride) {
Klass* ctxk = deps->at(i+ctxkj+0).as_klass(_oop_recorder);
DepValue x = deps->at(i+ctxkj+1); // following argument
if (ctxk == ctxk_encoded_as_null(dept, x.as_metadata(_oop_recorder))) {
skipj = ctxkj; // we win: maybe one less oop to keep track of
code_byte |= default_context_type_bit;
}
}
bytes.write_byte(code_byte);
for (int j = 0; j < stride; j++) {
if (j == skipj) continue;
DepValue v = deps->at(i+j);
int idx = v.index();
bytes.write_int(idx);
}
}
}
} else {
#endif // INCLUDE_JVMCI
for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
DepType dept = (DepType)deptv;
GrowableArray<ciBaseObject*>* deps = _deps[dept];
if (deps->length() == 0) continue;
int stride = dep_args(dept);
int ctxkj = dep_context_arg(dept); // -1 if no context arg
assert(stride > 0, "sanity");
for (int i = 0; i < deps->length(); i += stride) {
jbyte code_byte = (jbyte)dept;
int skipj = -1;
if (ctxkj >= 0 && ctxkj+1 < stride) {
ciKlass* ctxk = deps->at(i+ctxkj+0)->as_metadata()->as_klass();
ciBaseObject* x = deps->at(i+ctxkj+1); // following argument
if (ctxk == ctxk_encoded_as_null(dept, x)) {
skipj = ctxkj; // we win: maybe one less oop to keep track of
code_byte |= default_context_type_bit;
}
}
bytes.write_byte(code_byte);
for (int j = 0; j < stride; j++) {
if (j == skipj) continue;
ciBaseObject* v = deps->at(i+j);
int idx;
if (v->is_object()) {
idx = _oop_recorder->find_index(v->as_object()->constant_encoding());
} else {
ciMetadata* meta = v->as_metadata();
idx = _oop_recorder->find_index(meta->constant_encoding());
}
bytes.write_int(idx);
}
}
}
#if INCLUDE_JVMCI
}
#endif
// write a sentinel byte to mark the end
bytes.write_byte(end_marker);
// round it out to a word boundary
while (bytes.position() % sizeof(HeapWord) != 0) {
bytes.write_byte(end_marker);
}
// check whether the dept byte encoding really works
assert((jbyte)default_context_type_bit != 0, "byte overflow");
_content_bytes = bytes.buffer();
_size_in_bytes = bytes.position();
}
const char* Dependencies::_dep_name[TYPE_LIMIT] = {
"end_marker",
"evol_method",
"leaf_type",
"abstract_with_unique_concrete_subtype",
"abstract_with_no_concrete_subtype",
"concrete_with_no_concrete_subtype",
"unique_concrete_method",
"abstract_with_exclusive_concrete_subtypes_2",
"exclusive_concrete_methods_2",
"no_finalizable_subclasses",
"call_site_target_value"
};
int Dependencies::_dep_args[TYPE_LIMIT] = {
-1,// end_marker
1, // evol_method m
1, // leaf_type ctxk
2, // abstract_with_unique_concrete_subtype ctxk, k
1, // abstract_with_no_concrete_subtype ctxk
1, // concrete_with_no_concrete_subtype ctxk
2, // unique_concrete_method ctxk, m
3, // unique_concrete_subtypes_2 ctxk, k1, k2
3, // unique_concrete_methods_2 ctxk, m1, m2
1, // no_finalizable_subclasses ctxk
2 // call_site_target_value call_site, method_handle
};
const char* Dependencies::dep_name(Dependencies::DepType dept) {
if (!dept_in_mask(dept, all_types)) return "?bad-dep?";
return _dep_name[dept];
}
int Dependencies::dep_args(Dependencies::DepType dept) {
if (!dept_in_mask(dept, all_types)) return -1;
return _dep_args[dept];
}
void Dependencies::check_valid_dependency_type(DepType dept) {
guarantee(FIRST_TYPE <= dept && dept < TYPE_LIMIT, "invalid dependency type: %d", (int) dept);
}
Dependencies::DepType Dependencies::validate_dependencies(CompileTask* task, char** failure_detail) {
int klass_violations = 0;
DepType result = end_marker;
for (Dependencies::DepStream deps(this); deps.next(); ) {
Klass* witness = deps.check_dependency();
if (witness != NULL) {
if (klass_violations == 0) {
result = deps.type();
if (failure_detail != NULL && klass_violations == 0) {
// Use a fixed size buffer to prevent the string stream from
// resizing in the context of an inner resource mark.
char* buffer = NEW_RESOURCE_ARRAY(char, O_BUFLEN);
stringStream st(buffer, O_BUFLEN);
deps.print_dependency(witness, true, &st);
*failure_detail = st.as_string();
}
}
klass_violations++;
if (xtty == NULL) {
// If we're not logging then a single violation is sufficient,
// otherwise we want to log all the dependences which were
// violated.
break;
}
}
}
return result;
}
// for the sake of the compiler log, print out current dependencies:
void Dependencies::log_all_dependencies() {
if (log() == NULL) return;
ResourceMark rm;
for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
DepType dept = (DepType)deptv;
GrowableArray<ciBaseObject*>* deps = _deps[dept];
int deplen = deps->length();
if (deplen == 0) {
continue;
}
int stride = dep_args(dept);
GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(stride);
for (int i = 0; i < deps->length(); i += stride) {
for (int j = 0; j < stride; j++) {
// flush out the identities before printing
ciargs->push(deps->at(i+j));
}
write_dependency_to(log(), dept, ciargs);
ciargs->clear();
}
guarantee(deplen == deps->length(), "deps array cannot grow inside nested ResoureMark scope");
}
}
void Dependencies::write_dependency_to(CompileLog* log,
DepType dept,
GrowableArray<DepArgument>* args,
Klass* witness) {
if (log == NULL) {
return;
}
ResourceMark rm;
ciEnv* env = ciEnv::current();
GrowableArray<ciBaseObject*>* ciargs = new GrowableArray<ciBaseObject*>(args->length());
for (GrowableArrayIterator<DepArgument> it = args->begin(); it != args->end(); ++it) {
DepArgument arg = *it;
if (arg.is_oop()) {
ciargs->push(env->get_object(arg.oop_value()));
} else {
ciargs->push(env->get_metadata(arg.metadata_value()));
}
}
int argslen = ciargs->length();
Dependencies::write_dependency_to(log, dept, ciargs, witness);
guarantee(argslen == ciargs->length(), "ciargs array cannot grow inside nested ResoureMark scope");
}
void Dependencies::write_dependency_to(CompileLog* log,
DepType dept,
GrowableArray<ciBaseObject*>* args,
Klass* witness) {
if (log == NULL) {
return;
}
ResourceMark rm;
GrowableArray<int>* argids = new GrowableArray<int>(args->length());
for (GrowableArrayIterator<ciBaseObject*> it = args->begin(); it != args->end(); ++it) {
ciBaseObject* obj = *it;
if (obj->is_object()) {
argids->push(log->identify(obj->as_object()));
} else {
argids->push(log->identify(obj->as_metadata()));
}
}
if (witness != NULL) {
log->begin_elem("dependency_failed");
} else {
log->begin_elem("dependency");
}
log->print(" type='%s'", dep_name(dept));
const int ctxkj = dep_context_arg(dept); // -1 if no context arg
if (ctxkj >= 0 && ctxkj < argids->length()) {
log->print(" ctxk='%d'", argids->at(ctxkj));
}
// write remaining arguments, if any.
for (int j = 0; j < argids->length(); j++) {
if (j == ctxkj) continue; // already logged
if (j == 1) {
log->print( " x='%d'", argids->at(j));
} else {
log->print(" x%d='%d'", j, argids->at(j));
}
}
if (witness != NULL) {
log->object("witness", witness);
log->stamp();
}
log->end_elem();
}
void Dependencies::write_dependency_to(xmlStream* xtty,
DepType dept,
GrowableArray<DepArgument>* args,
Klass* witness) {
if (xtty == NULL) {
return;
}
Thread* thread = Thread::current();
HandleMark rm(thread);
ttyLocker ttyl;
int ctxkj = dep_context_arg(dept); // -1 if no context arg
if (witness != NULL) {
xtty->begin_elem("dependency_failed");
} else {
xtty->begin_elem("dependency");
}
xtty->print(" type='%s'", dep_name(dept));
if (ctxkj >= 0) {
xtty->object("ctxk", args->at(ctxkj).metadata_value());
}
// write remaining arguments, if any.
for (int j = 0; j < args->length(); j++) {
if (j == ctxkj) continue; // already logged
DepArgument arg = args->at(j);
if (j == 1) {
if (arg.is_oop()) {
xtty->object("x", Handle(thread, arg.oop_value()));
} else {
xtty->object("x", arg.metadata_value());
}
} else {
char xn[12]; sprintf(xn, "x%d", j);
if (arg.is_oop()) {
xtty->object(xn, Handle(thread, arg.oop_value()));
} else {
xtty->object(xn, arg.metadata_value());
}
}
}
if (witness != NULL) {
xtty->object("witness", witness);
xtty->stamp();
}
xtty->end_elem();
}
void Dependencies::print_dependency(DepType dept, GrowableArray<DepArgument>* args,
Klass* witness, outputStream* st) {
ResourceMark rm;
ttyLocker ttyl; // keep the following output all in one block
st->print_cr("%s of type %s",
(witness == NULL)? "Dependency": "Failed dependency",
dep_name(dept));
// print arguments
int ctxkj = dep_context_arg(dept); // -1 if no context arg
for (int j = 0; j < args->length(); j++) {
DepArgument arg = args->at(j);
bool put_star = false;
if (arg.is_null()) continue;
const char* what;
if (j == ctxkj) {
assert(arg.is_metadata(), "must be");
what = "context";
put_star = !Dependencies::is_concrete_klass((Klass*)arg.metadata_value());
} else if (arg.is_method()) {
what = "method ";
put_star = !Dependencies::is_concrete_method((Method*)arg.metadata_value(), NULL);
} else if (arg.is_klass()) {
what = "class ";
} else {
what = "object ";
}
st->print(" %s = %s", what, (put_star? "*": ""));
if (arg.is_klass()) {
st->print("%s", ((Klass*)arg.metadata_value())->external_name());
} else if (arg.is_method()) {
((Method*)arg.metadata_value())->print_value_on(st);
} else if (arg.is_oop()) {
arg.oop_value()->print_value_on(st);
} else {
ShouldNotReachHere(); // Provide impl for this type.
}
st->cr();
}
if (witness != NULL) {
bool put_star = !Dependencies::is_concrete_klass(witness);
st->print_cr(" witness = %s%s",
(put_star? "*": ""),
witness->external_name());
}
}
void Dependencies::DepStream::log_dependency(Klass* witness) {
if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
ResourceMark rm;
const int nargs = argument_count();
GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
for (int j = 0; j < nargs; j++) {
if (is_oop_argument(j)) {
args->push(argument_oop(j));
} else {
args->push(argument(j));
}
}
int argslen = args->length();
if (_deps != NULL && _deps->log() != NULL) {
if (ciEnv::current() != NULL) {
Dependencies::write_dependency_to(_deps->log(), type(), args, witness);
} else {
// Treat the CompileLog as an xmlstream instead
Dependencies::write_dependency_to((xmlStream*)_deps->log(), type(), args, witness);
}
} else {
Dependencies::write_dependency_to(xtty, type(), args, witness);
}
guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
}
void Dependencies::DepStream::print_dependency(Klass* witness, bool verbose, outputStream* st) {
ResourceMark rm;
int nargs = argument_count();
GrowableArray<DepArgument>* args = new GrowableArray<DepArgument>(nargs);
for (int j = 0; j < nargs; j++) {
if (is_oop_argument(j)) {
args->push(argument_oop(j));
} else {
args->push(argument(j));
}
}
int argslen = args->length();
Dependencies::print_dependency(type(), args, witness, st);
if (verbose) {
if (_code != NULL) {
st->print(" code: ");
_code->print_value_on(st);
st->cr();
}
}
guarantee(argslen == args->length(), "args array cannot grow inside nested ResoureMark scope");
}
/// Dependency stream support (decodes dependencies from an nmethod):
#ifdef ASSERT
void Dependencies::DepStream::initial_asserts(size_t byte_limit) {
assert(must_be_in_vm(), "raw oops here");
_byte_limit = byte_limit;
_type = (DepType)(end_marker-1); // defeat "already at end" assert
assert((_code!=NULL) + (_deps!=NULL) == 1, "one or t'other");
}
#endif //ASSERT
bool Dependencies::DepStream::next() {
assert(_type != end_marker, "already at end");
if (_bytes.position() == 0 && _code != NULL
&& _code->dependencies_size() == 0) {
// Method has no dependencies at all.
return false;
}
int code_byte = (_bytes.read_byte() & 0xFF);
if (code_byte == end_marker) {
DEBUG_ONLY(_type = end_marker);
return false;
} else {
int ctxk_bit = (code_byte & Dependencies::default_context_type_bit);
code_byte -= ctxk_bit;
DepType dept = (DepType)code_byte;
_type = dept;
Dependencies::check_valid_dependency_type(dept);
int stride = _dep_args[dept];
assert(stride == dep_args(dept), "sanity");
int skipj = -1;
if (ctxk_bit != 0) {
skipj = 0; // currently the only context argument is at zero
assert(skipj == dep_context_arg(dept), "zero arg always ctxk");
}
for (int j = 0; j < stride; j++) {
_xi[j] = (j == skipj)? 0: _bytes.read_int();
}
DEBUG_ONLY(_xi[stride] = -1); // help detect overruns
return true;
}
}
inline Metadata* Dependencies::DepStream::recorded_metadata_at(int i) {
Metadata* o = NULL;
if (_code != NULL) {
o = _code->metadata_at(i);
} else {
o = _deps->oop_recorder()->metadata_at(i);
}
return o;
}
inline oop Dependencies::DepStream::recorded_oop_at(int i) {
return (_code != NULL)
? _code->oop_at(i)
: JNIHandles::resolve(_deps->oop_recorder()->oop_at(i));
}
Metadata* Dependencies::DepStream::argument(int i) {
Metadata* result = recorded_metadata_at(argument_index(i));
if (result == NULL) { // Explicit context argument can be compressed
int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
if (ctxkj >= 0 && i == ctxkj && ctxkj+1 < argument_count()) {
result = ctxk_encoded_as_null(type(), argument(ctxkj+1));
}
}
assert(result == NULL || result->is_klass() || result->is_method(), "must be");
return result;
}
/**
* Returns a unique identifier for each dependency argument.
*/
uintptr_t Dependencies::DepStream::get_identifier(int i) {
if (is_oop_argument(i)) {
return (uintptr_t)(oopDesc*)argument_oop(i);
} else {
return (uintptr_t)argument(i);
}
}
oop Dependencies::DepStream::argument_oop(int i) {
oop result = recorded_oop_at(argument_index(i));
assert(oopDesc::is_oop_or_null(result), "must be");
return result;
}
Klass* Dependencies::DepStream::context_type() {
assert(must_be_in_vm(), "raw oops here");
// Most dependencies have an explicit context type argument.
{
int ctxkj = dep_context_arg(type()); // -1 if no explicit context arg
if (ctxkj >= 0) {
Metadata* k = argument(ctxkj);
assert(k != NULL && k->is_klass(), "type check");
return (Klass*)k;
}
}
// Some dependencies are using the klass of the first object
// argument as implicit context type.
{
int ctxkj = dep_implicit_context_arg(type());
if (ctxkj >= 0) {
Klass* k = argument_oop(ctxkj)->klass();
assert(k != NULL && k->is_klass(), "type check");
return (Klass*) k;
}
}
// And some dependencies don't have a context type at all,
// e.g. evol_method.
return NULL;
}
// ----------------- DependencySignature --------------------------------------
bool DependencySignature::equals(DependencySignature const& s1, DependencySignature const& s2) {
if ((s1.type() != s2.type()) || (s1.args_count() != s2.args_count())) {
return false;
}
for (int i = 0; i < s1.args_count(); i++) {
if (s1.arg(i) != s2.arg(i)) {
return false;
}
}
return true;
}
/// Checking dependencies:
// This hierarchy walker inspects subtypes of a given type,
// trying to find a "bad" class which breaks a dependency.
// Such a class is called a "witness" to the broken dependency.
// While searching around, we ignore "participants", which
// are already known to the dependency.
class ClassHierarchyWalker {
public:
enum { PARTICIPANT_LIMIT = 3 };
private:
// optional method descriptor to check for:
Symbol* _name;
Symbol* _signature;
// special classes which are not allowed to be witnesses:
Klass* _participants[PARTICIPANT_LIMIT+1];
int _num_participants;
// cache of method lookups
Method* _found_methods[PARTICIPANT_LIMIT+1];
// if non-zero, tells how many witnesses to convert to participants
int _record_witnesses;
void initialize(Klass* participant) {
_record_witnesses = 0;
_participants[0] = participant;
_found_methods[0] = NULL;
_num_participants = 0;
if (participant != NULL) {
// Terminating NULL.
_participants[1] = NULL;
_found_methods[1] = NULL;
_num_participants = 1;
}
}
void initialize_from_method(Method* m) {
assert(m != NULL && m->is_method(), "sanity");
_name = m->name();
_signature = m->signature();
}
public:
// The walker is initialized to recognize certain methods and/or types
// as friendly participants.
ClassHierarchyWalker(Klass* participant, Method* m) {
initialize_from_method(m);
initialize(participant);
}
ClassHierarchyWalker(Method* m) {
initialize_from_method(m);
initialize(NULL);
}
ClassHierarchyWalker(Klass* participant = NULL) {
_name = NULL;
_signature = NULL;
initialize(participant);
}
ClassHierarchyWalker(Klass* participants[], int num_participants) {
_name = NULL;
_signature = NULL;
initialize(NULL);
for (int i = 0; i < num_participants; ++i) {
add_participant(participants[i]);
}
}
// This is common code for two searches: One for concrete subtypes,
// the other for concrete method implementations and overrides.
bool doing_subtype_search() {
return _name == NULL;
}
int num_participants() { return _num_participants; }
Klass* participant(int n) {
assert((uint)n <= (uint)_num_participants, "oob");
return _participants[n];
}
// Note: If n==num_participants, returns NULL.
Method* found_method(int n) {
assert((uint)n <= (uint)_num_participants, "oob");
Method* fm = _found_methods[n];
assert(n == _num_participants || fm != NULL, "proper usage");
if (fm != NULL && fm->method_holder() != _participants[n]) {
// Default methods from interfaces can be added to classes. In
// that case the holder of the method is not the class but the
// interface where it's defined.
assert(fm->is_default_method(), "sanity");
return NULL;
}
return fm;
}
#ifdef ASSERT
// Assert that m is inherited into ctxk, without intervening overrides.
// (May return true even if this is not true, in corner cases where we punt.)
bool check_method_context(Klass* ctxk, Method* m) {
if (m->method_holder() == ctxk)
return true; // Quick win.
if (m->is_private())
return false; // Quick lose. Should not happen.
if (!(m->is_public() || m->is_protected()))
// The override story is complex when packages get involved.
return true; // Must punt the assertion to true.
Method* lm = ctxk->lookup_method(m->name(), m->signature());
if (lm == NULL && ctxk->is_instance_klass()) {
// It might be an interface method
lm = InstanceKlass::cast(ctxk)->lookup_method_in_ordered_interfaces(m->name(),
m->signature());
}
if (lm == m)
// Method m is inherited into ctxk.
return true;
if (lm != NULL) {
if (!(lm->is_public() || lm->is_protected())) {
// Method is [package-]private, so the override story is complex.
return true; // Must punt the assertion to true.
}
if (lm->is_static()) {
// Static methods don't override non-static so punt
return true;
}
if (!Dependencies::is_concrete_method(lm, ctxk) &&
!Dependencies::is_concrete_method(m, ctxk)) {
// They are both non-concrete
if (lm->method_holder()->is_subtype_of(m->method_holder())) {
// Method m is overridden by lm, but both are non-concrete.
return true;
}
if (lm->method_holder()->is_interface() && m->method_holder()->is_interface() &&
ctxk->is_subtype_of(m->method_holder()) && ctxk->is_subtype_of(lm->method_holder())) {
// Interface method defined in multiple super interfaces
return true;
}
}
}
ResourceMark rm;
tty->print_cr("Dependency method not found in the associated context:");
tty->print_cr(" context = %s", ctxk->external_name());
tty->print( " method = "); m->print_short_name(tty); tty->cr();
if (lm != NULL) {
tty->print( " found = "); lm->print_short_name(tty); tty->cr();
}
return false;
}
#endif
void add_participant(Klass* participant) {
assert(_num_participants + _record_witnesses < PARTICIPANT_LIMIT, "oob");
int np = _num_participants++;
_participants[np] = participant;
_participants[np+1] = NULL;
_found_methods[np+1] = NULL;
}
void record_witnesses(int add) {
if (add > PARTICIPANT_LIMIT) add = PARTICIPANT_LIMIT;
assert(_num_participants + add < PARTICIPANT_LIMIT, "oob");
_record_witnesses = add;
}
bool is_witness(Klass* k) {
if (doing_subtype_search()) {
return Dependencies::is_concrete_klass(k);
} else if (!k->is_instance_klass()) {
return false; // no methods to find in an array type
} else {
// Search class hierarchy first, skipping private implementations
// as they never override any inherited methods
Method* m = InstanceKlass::cast(k)->find_instance_method(_name, _signature, Klass::skip_private);
if (!Dependencies::is_concrete_method(m, k)) {
// Check for re-abstraction of method
if (!k->is_interface() && m != NULL && m->is_abstract()) {
// Found a matching abstract method 'm' in the class hierarchy.
// This is fine iff 'k' is an abstract class and all concrete subtypes
// of 'k' override 'm' and are participates of the current search.
ClassHierarchyWalker wf(_participants, _num_participants);
Klass* w = wf.find_witness_subtype(k);
if (w != NULL) {
Method* wm = InstanceKlass::cast(w)->find_instance_method(_name, _signature);
if (!Dependencies::is_concrete_method(wm, w)) {
// Found a concrete subtype 'w' which does not override abstract method 'm'.
// Bail out because 'm' could be called with 'w' as receiver (leading to an
// AbstractMethodError) and thus the method we are looking for is not unique.
_found_methods[_num_participants] = m;
return true;
}
}
}
// Check interface defaults also, if any exist.
Array<Method*>* default_methods = InstanceKlass::cast(k)->default_methods();
if (default_methods == NULL)
return false;
m = InstanceKlass::cast(k)->find_method(default_methods, _name, _signature);
if (!Dependencies::is_concrete_method(m, NULL))
return false;
}
_found_methods[_num_participants] = m;
// Note: If add_participant(k) is called,
// the method m will already be memoized for it.
return true;
}
}
bool is_participant(Klass* k) {
if (k == _participants[0]) {
return true;
} else if (_num_participants <= 1) {
return false;
} else {
return in_list(k, &_participants[1]);
}
}
bool ignore_witness(Klass* witness) {
if (_record_witnesses == 0) {
return false;
} else {
--_record_witnesses;
add_participant(witness);
return true;
}
}
static bool in_list(Klass* x, Klass** list) {
for (int i = 0; ; i++) {
Klass* y = list[i];
if (y == NULL) break;
if (y == x) return true;
}
return false; // not in list
}
private:
// the actual search method:
Klass* find_witness_anywhere(Klass* context_type,
bool participants_hide_witnesses,
bool top_level_call = true);
// the spot-checking version:
Klass* find_witness_in(KlassDepChange& changes,
Klass* context_type,
bool participants_hide_witnesses);
public:
Klass* find_witness_subtype(Klass* context_type, KlassDepChange* changes = NULL) {
assert(doing_subtype_search(), "must set up a subtype search");
// When looking for unexpected concrete types,
// do not look beneath expected ones.
const bool participants_hide_witnesses = true;
// CX > CC > C' is OK, even if C' is new.
// CX > { CC, C' } is not OK if C' is new, and C' is the witness.
if (changes != NULL) {
return find_witness_in(*changes, context_type, participants_hide_witnesses);
} else {
return find_witness_anywhere(context_type, participants_hide_witnesses);
}
}
Klass* find_witness_definer(Klass* context_type, KlassDepChange* changes = NULL) {
assert(!doing_subtype_search(), "must set up a method definer search");
// When looking for unexpected concrete methods,
// look beneath expected ones, to see if there are overrides.
const bool participants_hide_witnesses = true;
// CX.m > CC.m > C'.m is not OK, if C'.m is new, and C' is the witness.
if (changes != NULL) {
return find_witness_in(*changes, context_type, !participants_hide_witnesses);
} else {
return find_witness_anywhere(context_type, !participants_hide_witnesses);
}
}
};
#ifndef PRODUCT
static int deps_find_witness_calls = 0;
static int deps_find_witness_steps = 0;
static int deps_find_witness_recursions = 0;
static int deps_find_witness_singles = 0;
static int deps_find_witness_print = 0; // set to -1 to force a final print
static bool count_find_witness_calls() {
if (TraceDependencies || LogCompilation) {
int pcount = deps_find_witness_print + 1;
bool final_stats = (pcount == 0);
bool initial_call = (pcount == 1);
bool occasional_print = ((pcount & ((1<<10) - 1)) == 0);
if (pcount < 0) pcount = 1; // crude overflow protection
deps_find_witness_print = pcount;
if (VerifyDependencies && initial_call) {
tty->print_cr("Warning: TraceDependencies results may be inflated by VerifyDependencies");
}
if (occasional_print || final_stats) {
// Every now and then dump a little info about dependency searching.
if (xtty != NULL) {
ttyLocker ttyl;
xtty->elem("deps_find_witness calls='%d' steps='%d' recursions='%d' singles='%d'",
deps_find_witness_calls,
deps_find_witness_steps,
deps_find_witness_recursions,
deps_find_witness_singles);
}
if (final_stats || (TraceDependencies && WizardMode)) {
ttyLocker ttyl;
tty->print_cr("Dependency check (find_witness) "
"calls=%d, steps=%d (avg=%.1f), recursions=%d, singles=%d",
deps_find_witness_calls,
deps_find_witness_steps,
(double)deps_find_witness_steps / deps_find_witness_calls,
deps_find_witness_recursions,
deps_find_witness_singles);
}
}
return true;
}
return false;
}
#else
#define count_find_witness_calls() (0)
#endif //PRODUCT
Klass* ClassHierarchyWalker::find_witness_in(KlassDepChange& changes,
Klass* context_type,
bool participants_hide_witnesses) {
assert(changes.involves_context(context_type), "irrelevant dependency");
Klass* new_type = changes.new_type();
(void)count_find_witness_calls();
NOT_PRODUCT(deps_find_witness_singles++);
// Current thread must be in VM (not native mode, as in CI):
assert(must_be_in_vm(), "raw oops here");
// Must not move the class hierarchy during this check:
assert_locked_or_safepoint(Compile_lock);
int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
if (nof_impls > 1) {
// Avoid this case: *I.m > { A.m, C }; B.m > C
// %%% Until this is fixed more systematically, bail out.
// See corresponding comment in find_witness_anywhere.
return context_type;
}
assert(!is_participant(new_type), "only old classes are participants");
if (participants_hide_witnesses) {
// If the new type is a subtype of a participant, we are done.
for (int i = 0; i < num_participants(); i++) {
Klass* part = participant(i);
if (part == NULL) continue;
assert(changes.involves_context(part) == new_type->is_subtype_of(part),
"correct marking of participants, b/c new_type is unique");
if (changes.involves_context(part)) {
// new guy is protected from this check by previous participant
return NULL;
}
}
}
if (is_witness(new_type) &&
!ignore_witness(new_type)) {
return new_type;
}
return NULL;
}
// Walk hierarchy under a context type, looking for unexpected types.
// Do not report participant types, and recursively walk beneath
// them only if participants_hide_witnesses is false.
// If top_level_call is false, skip testing the context type,
// because the caller has already considered it.
Klass* ClassHierarchyWalker::find_witness_anywhere(Klass* context_type,
bool participants_hide_witnesses,
bool top_level_call) {
// Current thread must be in VM (not native mode, as in CI):
assert(must_be_in_vm(), "raw oops here");
// Must not move the class hierarchy during this check:
assert_locked_or_safepoint(Compile_lock);
bool do_counts = count_find_witness_calls();
// Check the root of the sub-hierarchy first.
if (top_level_call) {
if (do_counts) {
NOT_PRODUCT(deps_find_witness_calls++);
NOT_PRODUCT(deps_find_witness_steps++);
}
if (is_participant(context_type)) {
if (participants_hide_witnesses) return NULL;
// else fall through to search loop...
} else if (is_witness(context_type) && !ignore_witness(context_type)) {
// The context is an abstract class or interface, to start with.
return context_type;
}
}
// Now we must check each implementor and each subclass.
// Use a short worklist to avoid blowing the stack.
// Each worklist entry is a *chain* of subklass siblings to process.
const int CHAINMAX = 100; // >= 1 + InstanceKlass::implementors_limit
Klass* chains[CHAINMAX];
int chaini = 0; // index into worklist
Klass* chain; // scratch variable
#define ADD_SUBCLASS_CHAIN(k) { \
assert(chaini < CHAINMAX, "oob"); \
chain = k->subklass(); \
if (chain != NULL) chains[chaini++] = chain; }
// Look for non-abstract subclasses.
// (Note: Interfaces do not have subclasses.)
ADD_SUBCLASS_CHAIN(context_type);
// If it is an interface, search its direct implementors.
// (Their subclasses are additional indirect implementors.
// See InstanceKlass::add_implementor.)
// (Note: nof_implementors is always zero for non-interfaces.)
if (top_level_call) {
int nof_impls = InstanceKlass::cast(context_type)->nof_implementors();
if (nof_impls > 1) {
// Avoid this case: *I.m > { A.m, C }; B.m > C
// Here, I.m has 2 concrete implementations, but m appears unique
// as A.m, because the search misses B.m when checking C.
// The inherited method B.m was getting missed by the walker
// when interface 'I' was the starting point.
// %%% Until this is fixed more systematically, bail out.
// (Old CHA had the same limitation.)
return context_type;
}
if (nof_impls > 0) {
Klass* impl = InstanceKlass::cast(context_type)->implementor();
assert(impl != NULL, "just checking");
// If impl is the same as the context_type, then more than one
// implementor has seen. No exact info in this case.
if (impl == context_type) {
return context_type; // report an inexact witness to this sad affair
}
if (do_counts)
{ NOT_PRODUCT(deps_find_witness_steps++); }
if (is_participant(impl)) {
if (!participants_hide_witnesses) {
ADD_SUBCLASS_CHAIN(impl);
}
} else if (is_witness(impl) && !ignore_witness(impl)) {
return impl;
} else {
ADD_SUBCLASS_CHAIN(impl);
}
}
}
// Recursively process each non-trivial sibling chain.
while (chaini > 0) {
Klass* chain = chains[--chaini];
for (Klass* sub = chain; sub != NULL; sub = sub->next_sibling()) {
if (do_counts) { NOT_PRODUCT(deps_find_witness_steps++); }
if (is_participant(sub)) {
if (participants_hide_witnesses) continue;
// else fall through to process this guy's subclasses
} else if (is_witness(sub) && !ignore_witness(sub)) {
return sub;
}
if (chaini < (VerifyDependencies? 2: CHAINMAX)) {
// Fast path. (Partially disabled if VerifyDependencies.)
ADD_SUBCLASS_CHAIN(sub);
} else {
// Worklist overflow. Do a recursive call. Should be rare.
// The recursive call will have its own worklist, of course.
// (Note that sub has already been tested, so that there is
// no need for the recursive call to re-test. That's handy,
// since the recursive call sees sub as the context_type.)
if (do_counts) { NOT_PRODUCT(deps_find_witness_recursions++); }
Klass* witness = find_witness_anywhere(sub,
participants_hide_witnesses,
/*top_level_call=*/ false);
if (witness != NULL) return witness;
}
}
}
// No witness found. The dependency remains unbroken.
return NULL;
#undef ADD_SUBCLASS_CHAIN
}
bool Dependencies::is_concrete_klass(Klass* k) {
if (k->is_abstract()) return false;
// %%% We could treat classes which are concrete but
// have not yet been instantiated as virtually abstract.
// This would require a deoptimization barrier on first instantiation.
//if (k->is_not_instantiated()) return false;
return true;
}
bool Dependencies::is_concrete_method(Method* m, Klass * k) {
// NULL is not a concrete method,
// statics are irrelevant to virtual call sites,
// abstract methods are not concrete,
// overpass (error) methods are not concrete if k is abstract
//
// note "true" is conservative answer --
// overpass clause is false if k == NULL, implies return true if
// answer depends on overpass clause.
return ! ( m == NULL || m -> is_static() || m -> is_abstract() ||
(m->is_overpass() && k != NULL && k -> is_abstract()) );
}
Klass* Dependencies::find_finalizable_subclass(Klass* k) {
if (k->is_interface()) return NULL;
if (k->has_finalizer()) return k;
k = k->subklass();
while (k != NULL) {
Klass* result = find_finalizable_subclass(k);
if (result != NULL) return result;
k = k->next_sibling();
}
return NULL;
}
bool Dependencies::is_concrete_klass(ciInstanceKlass* k) {
if (k->is_abstract()) return false;
// We could also return false if k does not yet appear to be
// instantiated, if the VM version supports this distinction also.
//if (k->is_not_instantiated()) return false;
return true;
}
bool Dependencies::has_finalizable_subclass(ciInstanceKlass* k) {
return k->has_finalizable_subclass();
}
// Any use of the contents (bytecodes) of a method must be
// marked by an "evol_method" dependency, if those contents
// can change. (Note: A method is always dependent on itself.)
Klass* Dependencies::check_evol_method(Method* m) {
assert(must_be_in_vm(), "raw oops here");
// Did somebody do a JVMTI RedefineClasses while our backs were turned?
// Or is there a now a breakpoint?
// (Assumes compiled code cannot handle bkpts; change if UseFastBreakpoints.)
if (m->is_old()
|| m->number_of_breakpoints() > 0) {
return m->method_holder();
} else {
return NULL;
}
}
// This is a strong assertion: It is that the given type
// has no subtypes whatever. It is most useful for
// optimizing checks on reflected types or on array types.
// (Checks on types which are derived from real instances
// can be optimized more strongly than this, because we
// know that the checked type comes from a concrete type,
// and therefore we can disregard abstract types.)
Klass* Dependencies::check_leaf_type(Klass* ctxk) {
assert(must_be_in_vm(), "raw oops here");
assert_locked_or_safepoint(Compile_lock);
InstanceKlass* ctx = InstanceKlass::cast(ctxk);
Klass* sub = ctx->subklass();
if (sub != NULL) {
return sub;
} else if (ctx->nof_implementors() != 0) {
// if it is an interface, it must be unimplemented
// (if it is not an interface, nof_implementors is always zero)
Klass* impl = ctx->implementor();
assert(impl != NULL, "must be set");
return impl;
} else {
return NULL;
}
}
// Test the assertion that conck is the only concrete subtype* of ctxk.
// The type conck itself is allowed to have have further concrete subtypes.
// This allows the compiler to narrow occurrences of ctxk by conck,
// when dealing with the types of actual instances.
Klass* Dependencies::check_abstract_with_unique_concrete_subtype(Klass* ctxk,
Klass* conck,
KlassDepChange* changes) {
ClassHierarchyWalker wf(conck);
return wf.find_witness_subtype(ctxk, changes);
}
// If a non-concrete class has no concrete subtypes, it is not (yet)
// instantiatable. This can allow the compiler to make some paths go
// dead, if they are gated by a test of the type.
Klass* Dependencies::check_abstract_with_no_concrete_subtype(Klass* ctxk,
KlassDepChange* changes) {
// Find any concrete subtype, with no participants:
ClassHierarchyWalker wf;
return wf.find_witness_subtype(ctxk, changes);
}
// If a concrete class has no concrete subtypes, it can always be
// exactly typed. This allows the use of a cheaper type test.
Klass* Dependencies::check_concrete_with_no_concrete_subtype(Klass* ctxk,
KlassDepChange* changes) {
// Find any concrete subtype, with only the ctxk as participant:
ClassHierarchyWalker wf(ctxk);
return wf.find_witness_subtype(ctxk, changes);
}
// Find the unique concrete proper subtype of ctxk, or NULL if there
// is more than one concrete proper subtype. If there are no concrete
// proper subtypes, return ctxk itself, whether it is concrete or not.
// The returned subtype is allowed to have have further concrete subtypes.
// That is, return CC1 for CX > CC1 > CC2, but NULL for CX > { CC1, CC2 }.
Klass* Dependencies::find_unique_concrete_subtype(Klass* ctxk) {
ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
wf.record_witnesses(1); // Record one other witness when walking.
Klass* wit = wf.find_witness_subtype(ctxk);
if (wit != NULL) return NULL; // Too many witnesses.
Klass* conck = wf.participant(0);
if (conck == NULL) {
#ifndef PRODUCT
// Make sure the dependency mechanism will pass this discovery:
if (VerifyDependencies) {
// Turn off dependency tracing while actually testing deps.
FlagSetting fs(TraceDependencies, false);
if (!Dependencies::is_concrete_klass(ctxk)) {
guarantee(NULL ==
(void *)check_abstract_with_no_concrete_subtype(ctxk),
"verify dep.");
} else {
guarantee(NULL ==
(void *)check_concrete_with_no_concrete_subtype(ctxk),
"verify dep.");
}
}
#endif //PRODUCT
return ctxk; // Return ctxk as a flag for "no subtypes".
} else {
#ifndef PRODUCT
// Make sure the dependency mechanism will pass this discovery:
if (VerifyDependencies) {
// Turn off dependency tracing while actually testing deps.
FlagSetting fs(TraceDependencies, false);
if (!Dependencies::is_concrete_klass(ctxk)) {
guarantee(NULL == (void *)
check_abstract_with_unique_concrete_subtype(ctxk, conck),
"verify dep.");
}
}
#endif //PRODUCT
return conck;
}
}
// Test the assertion that the k[12] are the only concrete subtypes of ctxk,
// except possibly for further subtypes of k[12] themselves.
// The context type must be abstract. The types k1 and k2 are themselves
// allowed to have further concrete subtypes.
Klass* Dependencies::check_abstract_with_exclusive_concrete_subtypes(
Klass* ctxk,
Klass* k1,
Klass* k2,
KlassDepChange* changes) {
ClassHierarchyWalker wf;
wf.add_participant(k1);
wf.add_participant(k2);
return wf.find_witness_subtype(ctxk, changes);
}
// Search ctxk for concrete implementations. If there are klen or fewer,
// pack them into the given array and return the number.
// Otherwise, return -1, meaning the given array would overflow.
// (Note that a return of 0 means there are exactly no concrete subtypes.)
// In this search, if ctxk is concrete, it will be reported alone.
// For any type CC reported, no proper subtypes of CC will be reported.
int Dependencies::find_exclusive_concrete_subtypes(Klass* ctxk,
int klen,
Klass* karray[]) {
ClassHierarchyWalker wf;
wf.record_witnesses(klen);
Klass* wit = wf.find_witness_subtype(ctxk);
if (wit != NULL) return -1; // Too many witnesses.
int num = wf.num_participants();
assert(num <= klen, "oob");
// Pack the result array with the good news.
for (int i = 0; i < num; i++)
karray[i] = wf.participant(i);
#ifndef PRODUCT
// Make sure the dependency mechanism will pass this discovery:
if (VerifyDependencies) {
// Turn off dependency tracing while actually testing deps.
FlagSetting fs(TraceDependencies, false);
switch (Dependencies::is_concrete_klass(ctxk)? -1: num) {
case -1: // ctxk was itself concrete
guarantee(num == 1 && karray[0] == ctxk, "verify dep.");
break;
case 0:
guarantee(NULL == (void *)check_abstract_with_no_concrete_subtype(ctxk),
"verify dep.");
break;
case 1:
guarantee(NULL == (void *)
check_abstract_with_unique_concrete_subtype(ctxk, karray[0]),
"verify dep.");
break;
case 2:
guarantee(NULL == (void *)
check_abstract_with_exclusive_concrete_subtypes(ctxk,
karray[0],
karray[1]),
"verify dep.");
break;
default:
ShouldNotReachHere(); // klen > 2 yet supported
}
}
#endif //PRODUCT
return num;
}
// If a class (or interface) has a unique concrete method uniqm, return NULL.
// Otherwise, return a class that contains an interfering method.
Klass* Dependencies::check_unique_concrete_method(Klass* ctxk, Method* uniqm,
KlassDepChange* changes) {
// Here is a missing optimization: If uniqm->is_final(),
// we don't really need to search beneath it for overrides.
// This is probably not important, since we don't use dependencies
// to track final methods. (They can't be "definalized".)
ClassHierarchyWalker wf(uniqm->method_holder(), uniqm);
return wf.find_witness_definer(ctxk, changes);
}
// Find the set of all non-abstract methods under ctxk that match m.
// (The method m must be defined or inherited in ctxk.)
// Include m itself in the set, unless it is abstract.
// If this set has exactly one element, return that element.
Method* Dependencies::find_unique_concrete_method(Klass* ctxk, Method* m) {
// Return NULL if m is marked old; must have been a redefined method.
if (m->is_old()) {
return NULL;
}
ClassHierarchyWalker wf(m);
assert(wf.check_method_context(ctxk, m), "proper context");
wf.record_witnesses(1);
Klass* wit = wf.find_witness_definer(ctxk);
if (wit != NULL) return NULL; // Too many witnesses.
Method* fm = wf.found_method(0); // Will be NULL if num_parts == 0.
if (Dependencies::is_concrete_method(m, ctxk)) {
if (fm == NULL) {
// It turns out that m was always the only implementation.
fm = m;
} else if (fm != m) {
// Two conflicting implementations after all.
// (This can happen if m is inherited into ctxk and fm overrides it.)
return NULL;
}
}
#ifndef PRODUCT
// Make sure the dependency mechanism will pass this discovery:
if (VerifyDependencies && fm != NULL) {
guarantee(NULL == (void *)check_unique_concrete_method(ctxk, fm),
"verify dep.");
}
#endif //PRODUCT
return fm;
}
Klass* Dependencies::check_exclusive_concrete_methods(Klass* ctxk,
Method* m1,
Method* m2,
KlassDepChange* changes) {
ClassHierarchyWalker wf(m1);
wf.add_participant(m1->method_holder());
wf.add_participant(m2->method_holder());
return wf.find_witness_definer(ctxk, changes);
}
Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes) {
Klass* search_at = ctxk;
if (changes != NULL)
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