--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/code/dependencies.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,1549 @@
+/*
+ * Copyright 2005-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_dependencies.cpp.incl"
+
+
+#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);
+ DEBUG_ONLY(_deps[end_marker] = NULL);
+ for (int i = (int)FIRST_TYPE; i < (int)TYPE_LIMIT; i++) {
+ _deps[i] = new(arena) GrowableArray<ciObject*>(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);
+ 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);
+}
+
+// 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<ciObject*>* deps,
+ int ctxk_i, ciKlass* ctxk2) {
+ ciKlass* ctxk1 = deps->at(ctxk_i)->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(Dependencies::DepType dept, ciObject* x) {
+ assert(dep_args(dept) == 1, "sanity");
+ log_dependency(dept, x);
+ GrowableArray<ciObject*>* 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(Dependencies::DepType dept,
+ ciKlass* ctxk, ciObject* x) {
+ assert(dep_context_arg(dept) == 0, "sanity");
+ assert(dep_args(dept) == 2, "sanity");
+ log_dependency(dept, ctxk, x);
+ GrowableArray<ciObject*>* deps = _deps[dept];
+
+ // see if the same (or a similar) dep is already recorded
+ if (note_dep_seen(dept, x)) {
+ // look in this bucket for redundant assertions
+ const int stride = 2;
+ for (int i = deps->length(); (i -= stride) >= 0; ) {
+ ciObject* x1 = deps->at(i+1);
+ if (x == x1) { // same subject; 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);
+}
+
+void Dependencies::assert_common_3(Dependencies::DepType dept,
+ ciKlass* ctxk, ciObject* x, ciObject* x2) {
+ assert(dep_context_arg(dept) == 0, "sanity");
+ assert(dep_args(dept) == 3, "sanity");
+ log_dependency(dept, ctxk, x, x2);
+ GrowableArray<ciObject*>* 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 != ctxk);
+ break;
+ case exclusive_concrete_methods_2:
+ swap = (x->ident() > x2->ident() && x->as_method()->holder() != ctxk);
+ break;
+ }
+ if (swap) { ciObject* 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; ) {
+ ciObject* y = deps->at(i+1);
+ ciObject* 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);
+}
+
+/// 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(ciObject** p1, ciObject** 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(ciObject** p1, ciObject** p2)
+{ return sort_dep(p1, p2, 1); }
+static int sort_dep_arg_2(ciObject** p1, ciObject** p2)
+{ return sort_dep(p1, p2, 2); }
+static int sort_dep_arg_3(ciObject** p1, ciObject** p2)
+{ return sort_dep(p1, p2, 3); }
+
+void Dependencies::sort_all_deps() {
+ for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
+ DepType dept = (DepType)deptv;
+ GrowableArray<ciObject*>* 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();
+ }
+ }
+}
+
+size_t Dependencies::estimate_size_in_bytes() {
+ size_t est_size = 100;
+ for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
+ DepType dept = (DepType)deptv;
+ GrowableArray<ciObject*>* deps = _deps[dept];
+ est_size += deps->length()*2; // tags and argument(s)
+ }
+ return est_size;
+}
+
+ciKlass* Dependencies::ctxk_encoded_as_null(DepType dept, ciObject* x) {
+ switch (dept) {
+ case abstract_with_exclusive_concrete_subtypes_2:
+ return x->as_klass();
+ case unique_concrete_method:
+ case exclusive_concrete_methods_2:
+ return x->as_method()->holder();
+ }
+ return NULL; // let NULL be NULL
+}
+
+klassOop Dependencies::ctxk_encoded_as_null(DepType dept, oop x) {
+ assert(must_be_in_vm(), "raw oops here");
+ switch (dept) {
+ case abstract_with_exclusive_concrete_subtypes_2:
+ assert(x->is_klass(), "sanity");
+ return (klassOop) x;
+ case unique_concrete_method:
+ case exclusive_concrete_methods_2:
+ assert(x->is_method(), "sanity");
+ return ((methodOop)x)->method_holder();
+ }
+ 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());
+
+ for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
+ DepType dept = (DepType)deptv;
+ GrowableArray<ciObject*>* 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_klass();
+ ciObject* 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;
+ bytes.write_int(_oop_recorder->find_index(deps->at(i+j)->encoding()));
+ }
+ }
+ }
+
+ // 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"
+};
+
+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
+};
+
+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];
+}
+
+// for the sake of the compiler log, print out current dependencies:
+void Dependencies::log_all_dependencies() {
+ if (log() == NULL) return;
+ ciObject* args[max_arg_count];
+ for (int deptv = (int)FIRST_TYPE; deptv < (int)TYPE_LIMIT; deptv++) {
+ DepType dept = (DepType)deptv;
+ GrowableArray<ciObject*>* deps = _deps[dept];
+ if (deps->length() == 0) continue;
+ int stride = dep_args(dept);
+ for (int i = 0; i < deps->length(); i += stride) {
+ for (int j = 0; j < stride; j++) {
+ // flush out the identities before printing
+ args[j] = deps->at(i+j);
+ }
+ write_dependency_to(log(), dept, stride, args);
+ }
+ }
+}
+
+void Dependencies::write_dependency_to(CompileLog* log,
+ DepType dept,
+ int nargs, oop args[],
+ klassOop witness) {
+ if (log == NULL) {
+ return;
+ }
+ ciEnv* env = ciEnv::current();
+ ciObject* ciargs[max_arg_count];
+ assert(nargs <= max_arg_count, "oob");
+ for (int j = 0; j < nargs; j++) {
+ ciargs[j] = env->get_object(args[j]);
+ }
+ Dependencies::write_dependency_to(log, dept, nargs, ciargs, witness);
+}
+
+void Dependencies::write_dependency_to(CompileLog* log,
+ DepType dept,
+ int nargs, ciObject* args[],
+ klassOop witness) {
+ if (log == NULL) return;
+ assert(nargs <= max_arg_count, "oob");
+ int argids[max_arg_count];
+ int ctxkj = dep_context_arg(dept); // -1 if no context arg
+ int j;
+ for (j = 0; j < nargs; j++) {
+ argids[j] = log->identify(args[j]);
+ }
+ if (witness != NULL) {
+ log->begin_elem("dependency_failed");
+ } else {
+ log->begin_elem("dependency");
+ }
+ log->print(" type='%s'", dep_name(dept));
+ if (ctxkj >= 0) {
+ log->print(" ctxk='%d'", argids[ctxkj]);
+ }
+ // write remaining arguments, if any.
+ for (j = 0; j < nargs; j++) {
+ if (j == ctxkj) continue; // already logged
+ if (j == 1) {
+ log->print( " x='%d'", argids[j]);
+ } else {
+ log->print(" x%d='%d'", j, argids[j]);
+ }
+ }
+ if (witness != NULL) {
+ log->object("witness", witness);
+ log->stamp();
+ }
+ log->end_elem();
+}
+
+void Dependencies::write_dependency_to(xmlStream* xtty,
+ DepType dept,
+ int nargs, oop args[],
+ klassOop witness) {
+ if (xtty == NULL) return;
+ 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[ctxkj]);
+ }
+ // write remaining arguments, if any.
+ for (int j = 0; j < nargs; j++) {
+ if (j == ctxkj) continue; // already logged
+ if (j == 1) {
+ xtty->object("x", args[j]);
+ } else {
+ char xn[10]; sprintf(xn, "x%d", j);
+ xtty->object(xn, args[j]);
+ }
+ }
+ if (witness != NULL) {
+ xtty->object("witness", witness);
+ xtty->stamp();
+ }
+ xtty->end_elem();
+}
+
+void Dependencies::print_dependency(DepType dept, int nargs, oop args[],
+ klassOop witness) {
+ ResourceMark rm;
+ ttyLocker ttyl; // keep the following output all in one block
+ tty->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 < nargs; j++) {
+ oop arg = args[j];
+ bool put_star = false;
+ if (arg == NULL) continue;
+ const char* what;
+ if (j == ctxkj) {
+ what = "context";
+ put_star = !Dependencies::is_concrete_klass((klassOop)arg);
+ } else if (arg->is_method()) {
+ what = "method ";
+ put_star = !Dependencies::is_concrete_method((methodOop)arg);
+ } else if (arg->is_klass()) {
+ what = "class ";
+ } else {
+ what = "object ";
+ }
+ tty->print(" %s = %s", what, (put_star? "*": ""));
+ if (arg->is_klass())
+ tty->print("%s", Klass::cast((klassOop)arg)->external_name());
+ else
+ arg->print_value();
+ tty->cr();
+ }
+ if (witness != NULL) {
+ bool put_star = !Dependencies::is_concrete_klass(witness);
+ tty->print_cr(" witness = %s%s",
+ (put_star? "*": ""),
+ Klass::cast(witness)->external_name());
+ }
+}
+
+void Dependencies::DepStream::log_dependency(klassOop witness) {
+ if (_deps == NULL && xtty == NULL) return; // fast cutout for runtime
+ int nargs = argument_count();
+ oop args[max_arg_count];
+ for (int j = 0; j < nargs; j++) {
+ args[j] = argument(j);
+ }
+ if (_deps != NULL && _deps->log() != NULL) {
+ Dependencies::write_dependency_to(_deps->log(),
+ type(), nargs, args, witness);
+ } else {
+ Dependencies::write_dependency_to(xtty,
+ type(), nargs, args, witness);
+ }
+}
+
+void Dependencies::DepStream::print_dependency(klassOop witness, bool verbose) {
+ int nargs = argument_count();
+ oop args[max_arg_count];
+ for (int j = 0; j < nargs; j++) {
+ args[j] = argument(j);
+ }
+ Dependencies::print_dependency(type(), nargs, args, witness);
+ if (verbose) {
+ if (_code != NULL) {
+ tty->print(" code: ");
+ _code->print_value_on(tty);
+ tty->cr();
+ }
+ }
+}
+
+
+/// 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;
+ guarantee((dept - FIRST_TYPE) < (TYPE_LIMIT - FIRST_TYPE),
+ "bad dependency type tag");
+ 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 oop Dependencies::DepStream::recorded_oop_at(int i) {
+ return (_code != NULL)
+ ? _code->oop_at(i)
+ : JNIHandles::resolve(_deps->oop_recorder()->handle_at(i));
+}
+
+oop Dependencies::DepStream::argument(int i) {
+ return recorded_oop_at(argument_index(i));
+}
+
+klassOop Dependencies::DepStream::context_type() {
+ assert(must_be_in_vm(), "raw oops here");
+ int ctxkj = dep_context_arg(_type); // -1 if no context arg
+ if (ctxkj < 0) {
+ return NULL; // for example, evol_method
+ } else {
+ oop k = recorded_oop_at(_xi[ctxkj]);
+ if (k != NULL) { // context type was not compressed away
+ assert(k->is_klass(), "type check");
+ return (klassOop) k;
+ } else { // recompute "default" context type
+ return ctxk_encoded_as_null(_type, recorded_oop_at(_xi[ctxkj+1]));
+ }
+ }
+}
+
+/// 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:
+ symbolOop _name;
+ symbolOop _signature;
+
+ // special classes which are not allowed to be witnesses:
+ klassOop _participants[PARTICIPANT_LIMIT+1];
+ int _num_participants;
+
+ // cache of method lookups
+ methodOop _found_methods[PARTICIPANT_LIMIT+1];
+
+ // if non-zero, tells how many witnesses to convert to participants
+ int _record_witnesses;
+
+ void initialize(klassOop 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(methodOop 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(klassOop participant, methodOop m) {
+ initialize_from_method(m);
+ initialize(participant);
+ }
+ ClassHierarchyWalker(methodOop m) {
+ initialize_from_method(m);
+ initialize(NULL);
+ }
+ ClassHierarchyWalker(klassOop participant = NULL) {
+ _name = NULL;
+ _signature = NULL;
+ initialize(participant);
+ }
+
+ // 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; }
+ klassOop participant(int n) {
+ assert((uint)n <= (uint)_num_participants, "oob");
+ return _participants[n];
+ }
+
+ // Note: If n==num_participants, returns NULL.
+ methodOop found_method(int n) {
+ assert((uint)n <= (uint)_num_participants, "oob");
+ methodOop fm = _found_methods[n];
+ assert(n == _num_participants || fm != NULL, "proper usage");
+ assert(fm == NULL || fm->method_holder() == _participants[n], "sanity");
+ 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(klassOop ctxk, methodOop 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.
+ Klass* k = Klass::cast(ctxk);
+ methodOop lm = k->lookup_method(m->name(), m->signature());
+ if (lm == NULL && k->oop_is_instance()) {
+ // It might be an abstract interface method, devoid of mirandas.
+ lm = ((instanceKlass*)k)->lookup_method_in_all_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 ( !Dependencies::is_concrete_method(lm)
+ && !Dependencies::is_concrete_method(m)
+ && Klass::cast(lm->method_holder())->is_subtype_of(m->method_holder()))
+ // Method m is overridden by lm, but both are non-concrete.
+ return true;
+ }
+ ResourceMark rm;
+ tty->print_cr("Dependency method not found in the associated context:");
+ tty->print_cr(" context = %s", Klass::cast(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(klassOop 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(klassOop k) {
+ if (doing_subtype_search()) {
+ return Dependencies::is_concrete_klass(k);
+ } else {
+ methodOop m = instanceKlass::cast(k)->find_method(_name, _signature);
+ if (m == NULL || !Dependencies::is_concrete_method(m)) 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(klassOop k) {
+ if (k == _participants[0]) {
+ return true;
+ } else if (_num_participants <= 1) {
+ return false;
+ } else {
+ return in_list(k, &_participants[1]);
+ }
+ }
+ bool ignore_witness(klassOop witness) {
+ if (_record_witnesses == 0) {
+ return false;
+ } else {
+ --_record_witnesses;
+ add_participant(witness);
+ return true;
+ }
+ }
+ static bool in_list(klassOop x, klassOop* list) {
+ for (int i = 0; ; i++) {
+ klassOop y = list[i];
+ if (y == NULL) break;
+ if (y == x) return true;
+ }
+ return false; // not in list
+ }
+
+ private:
+ // the actual search method:
+ klassOop find_witness_anywhere(klassOop context_type,
+ bool participants_hide_witnesses,
+ bool top_level_call = true);
+ // the spot-checking version:
+ klassOop find_witness_in(DepChange& changes,
+ klassOop context_type,
+ bool participants_hide_witnesses);
+ public:
+ klassOop find_witness_subtype(klassOop context_type, DepChange* 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);
+ }
+ }
+ klassOop find_witness_definer(klassOop context_type, DepChange* 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) {
+ 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)) {
+ 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
+
+
+klassOop ClassHierarchyWalker::find_witness_in(DepChange& changes,
+ klassOop context_type,
+ bool participants_hide_witnesses) {
+ assert(changes.involves_context(context_type), "irrelevant dependency");
+ klassOop new_type = changes.new_type();
+
+ 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);
+
+ 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++) {
+ klassOop part = participant(i);
+ if (part == NULL) continue;
+ assert(changes.involves_context(part) == Klass::cast(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.
+klassOop ClassHierarchyWalker::find_witness_anywhere(klassOop 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 = instanceKlass::cast(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.)
+ 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;
+ }
+ for (int i = 0; i < nof_impls; i++) {
+ klassOop impl = instanceKlass::cast(context_type)->implementor(i);
+ if (impl == NULL) {
+ // implementors array overflowed => no exact info.
+ 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) continue;
+ // else fall through to process this guy's subclasses
+ } else if (is_witness(impl) && !ignore_witness(impl)) {
+ return impl;
+ }
+ ADD_SUBCLASS_CHAIN(impl);
+ }
+
+ // Recursively process each non-trivial sibling chain.
+ while (chaini > 0) {
+ Klass* chain = chains[--chaini];
+ for (Klass* subk = chain; subk != NULL; subk = subk->next_sibling()) {
+ klassOop sub = subk->as_klassOop();
+ 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++); }
+ klassOop 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(klassOop k) {
+ if (Klass::cast(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(methodOop m) {
+ if (m->is_abstract()) return false;
+ // %%% We could treat unexecuted methods as virtually abstract also.
+ // This would require a deoptimization barrier on first execution.
+ return !m->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 return also 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::is_concrete_method(ciMethod* m) {
+ // Statics are irrelevant to virtual call sites.
+ if (m->is_static()) return false;
+
+ // We could return also false if m does not yet appear to be
+ // executed, if the VM version supports this distinction also.
+ return !m->is_abstract();
+}
+
+
+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.)
+klassOop Dependencies::check_evol_method(methodOop 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.)
+klassOop Dependencies::check_leaf_type(klassOop 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->as_klassOop();
+ } 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)
+ klassOop impl = ctx->implementor(0);
+ return (impl != NULL)? impl: ctxk;
+ } 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.
+klassOop Dependencies::check_abstract_with_unique_concrete_subtype(klassOop ctxk,
+ klassOop conck,
+ DepChange* 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.
+klassOop Dependencies::check_abstract_with_no_concrete_subtype(klassOop ctxk,
+ DepChange* 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.
+klassOop Dependencies::check_concrete_with_no_concrete_subtype(klassOop ctxk,
+ DepChange* 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 }.
+klassOop Dependencies::find_unique_concrete_subtype(klassOop ctxk) {
+ ClassHierarchyWalker wf(ctxk); // Ignore ctxk when walking.
+ wf.record_witnesses(1); // Record one other witness when walking.
+ klassOop wit = wf.find_witness_subtype(ctxk);
+ if (wit != NULL) return NULL; // Too many witnesses.
+ klassOop 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.
+klassOop Dependencies::check_abstract_with_exclusive_concrete_subtypes(
+ klassOop ctxk,
+ klassOop k1,
+ klassOop k2,
+ DepChange* 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(klassOop ctxk,
+ int klen,
+ klassOop karray[]) {
+ ClassHierarchyWalker wf;
+ wf.record_witnesses(klen);
+ klassOop 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.
+klassOop Dependencies::check_unique_concrete_method(klassOop ctxk, methodOop uniqm,
+ DepChange* 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.
+methodOop Dependencies::find_unique_concrete_method(klassOop ctxk, methodOop m) {
+ ClassHierarchyWalker wf(m);
+ assert(wf.check_method_context(ctxk, m), "proper context");
+ wf.record_witnesses(1);
+ klassOop wit = wf.find_witness_definer(ctxk);
+ if (wit != NULL) return NULL; // Too many witnesses.
+ methodOop fm = wf.found_method(0); // Will be NULL if num_parts == 0.
+ if (Dependencies::is_concrete_method(m)) {
+ 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;
+}
+
+klassOop Dependencies::check_exclusive_concrete_methods(klassOop ctxk,
+ methodOop m1,
+ methodOop m2,
+ DepChange* changes) {
+ ClassHierarchyWalker wf(m1);
+ wf.add_participant(m1->method_holder());
+ wf.add_participant(m2->method_holder());
+ return wf.find_witness_definer(ctxk, changes);
+}
+
+// Find the set of all non-abstract methods under ctxk that match m[0].
+// (The method m[0] must be defined or inherited in ctxk.)
+// Include m itself in the set, unless it is abstract.
+// Fill the given array m[0..(mlen-1)] with this set, and return the length.
+// (The length may be zero if no concrete methods are found anywhere.)
+// If there are too many concrete methods to fit in marray, return -1.
+int Dependencies::find_exclusive_concrete_methods(klassOop ctxk,
+ int mlen,
+ methodOop marray[]) {
+ methodOop m0 = marray[0];
+ ClassHierarchyWalker wf(m0);
+ assert(wf.check_method_context(ctxk, m0), "proper context");
+ wf.record_witnesses(mlen);
+ bool participants_hide_witnesses = true;
+ klassOop wit = wf.find_witness_definer(ctxk);
+ if (wit != NULL) return -1; // Too many witnesses.
+ int num = wf.num_participants();
+ assert(num <= mlen, "oob");
+ // Keep track of whether m is also part of the result set.
+ int mfill = 0;
+ assert(marray[mfill] == m0, "sanity");
+ if (Dependencies::is_concrete_method(m0))
+ mfill++; // keep m0 as marray[0], the first result
+ for (int i = 0; i < num; i++) {
+ methodOop fm = wf.found_method(i);
+ if (fm == m0) continue; // Already put this guy in the list.
+ if (mfill == mlen) {
+ return -1; // Oops. Too many methods after all!
+ }
+ marray[mfill++] = fm;
+ }
+#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 (mfill) {
+ case 1:
+ guarantee(NULL == (void *)check_unique_concrete_method(ctxk, marray[0]),
+ "verify dep.");
+ break;
+ case 2:
+ guarantee(NULL == (void *)
+ check_exclusive_concrete_methods(ctxk, marray[0], marray[1]),
+ "verify dep.");
+ break;
+ default:
+ ShouldNotReachHere(); // mlen > 2 yet supported
+ }
+ }
+#endif //PRODUCT
+ return mfill;
+}
+
+
+klassOop Dependencies::check_has_no_finalizable_subclasses(klassOop ctxk, DepChange* changes) {
+ Klass* search_at = ctxk->klass_part();
+ if (changes != NULL)
+ search_at = changes->new_type()->klass_part(); // just look at the new bit
+ Klass* result = find_finalizable_subclass(search_at);
+ if (result == NULL) {
+ return NULL;
+ }
+ return result->as_klassOop();
+}
+
+
+klassOop Dependencies::DepStream::check_dependency_impl(DepChange* changes) {
+ assert_locked_or_safepoint(Compile_lock);
+
+ klassOop witness = NULL;
+ switch (type()) {
+ case evol_method:
+ witness = check_evol_method(method_argument(0));
+ break;
+ case leaf_type:
+ witness = check_leaf_type(context_type());
+ break;
+ case abstract_with_unique_concrete_subtype:
+ witness = check_abstract_with_unique_concrete_subtype(context_type(),
+ type_argument(1),
+ changes);
+ break;
+ case abstract_with_no_concrete_subtype:
+ witness = check_abstract_with_no_concrete_subtype(context_type(),
+ changes);
+ break;
+ case concrete_with_no_concrete_subtype:
+ witness = check_concrete_with_no_concrete_subtype(context_type(),
+ changes);
+ break;
+ case unique_concrete_method:
+ witness = check_unique_concrete_method(context_type(),
+ method_argument(1),
+ changes);
+ break;
+ case abstract_with_exclusive_concrete_subtypes_2:
+ witness = check_abstract_with_exclusive_concrete_subtypes(context_type(),
+ type_argument(1),
+ type_argument(2),
+ changes);
+ break;
+ case exclusive_concrete_methods_2:
+ witness = check_exclusive_concrete_methods(context_type(),
+ method_argument(1),
+ method_argument(2),
+ changes);
+ break;
+ case no_finalizable_subclasses:
+ witness = check_has_no_finalizable_subclasses(context_type(),
+ changes);
+ break;
+ default:
+ witness = NULL;
+ ShouldNotReachHere();
+ break;
+ }
+ if (witness != NULL) {
+ if (TraceDependencies) {
+ print_dependency(witness, /*verbose=*/ true);
+ }
+ // The following is a no-op unless logging is enabled:
+ log_dependency(witness);
+ }
+ return witness;
+}
+
+
+klassOop Dependencies::DepStream::spot_check_dependency_at(DepChange& changes) {
+ if (!changes.involves_context(context_type()))
+ // irrelevant dependency; skip it
+ return NULL;
+
+ return check_dependency_impl(&changes);
+}
+
+
+void DepChange::initialize() {
+ // entire transaction must be under this lock:
+ assert_lock_strong(Compile_lock);
+
+ // Mark all dependee and all its superclasses
+ // Mark transitive interfaces
+ for (ContextStream str(*this); str.next(); ) {
+ klassOop d = str.klass();
+ assert(!instanceKlass::cast(d)->is_marked_dependent(), "checking");
+ instanceKlass::cast(d)->set_is_marked_dependent(true);
+ }
+}
+
+DepChange::~DepChange() {
+ // Unmark all dependee and all its superclasses
+ // Unmark transitive interfaces
+ for (ContextStream str(*this); str.next(); ) {
+ klassOop d = str.klass();
+ instanceKlass::cast(d)->set_is_marked_dependent(false);
+ }
+}
+
+bool DepChange::involves_context(klassOop k) {
+ if (k == NULL || !Klass::cast(k)->oop_is_instance()) {
+ return false;
+ }
+ instanceKlass* ik = instanceKlass::cast(k);
+ bool is_contained = ik->is_marked_dependent();
+ assert(is_contained == Klass::cast(new_type())->is_subtype_of(k),
+ "correct marking of potential context types");
+ return is_contained;
+}
+
+bool DepChange::ContextStream::next() {
+ switch (_change_type) {
+ case Start_Klass: // initial state; _klass is the new type
+ _ti_base = instanceKlass::cast(_klass)->transitive_interfaces();
+ _ti_index = 0;
+ _change_type = Change_new_type;
+ return true;
+ case Change_new_type:
+ // fall through:
+ _change_type = Change_new_sub;
+ case Change_new_sub:
+ _klass = instanceKlass::cast(_klass)->super();
+ if (_klass != NULL) {
+ return true;
+ }
+ // else set up _ti_limit and fall through:
+ _ti_limit = (_ti_base == NULL) ? 0 : _ti_base->length();
+ _change_type = Change_new_impl;
+ case Change_new_impl:
+ if (_ti_index < _ti_limit) {
+ _klass = klassOop( _ti_base->obj_at(_ti_index++) );
+ return true;
+ }
+ // fall through:
+ _change_type = NO_CHANGE; // iterator is exhausted
+ case NO_CHANGE:
+ break;
+ default:
+ ShouldNotReachHere();
+ }
+ return false;
+}
+
+void DepChange::print() {
+ int nsup = 0, nint = 0;
+ for (ContextStream str(*this); str.next(); ) {
+ klassOop k = str.klass();
+ switch (str._change_type) {
+ case Change_new_type:
+ tty->print_cr(" dependee = %s", instanceKlass::cast(k)->external_name());
+ break;
+ case Change_new_sub:
+ if (!WizardMode)
+ ++nsup;
+ else tty->print_cr(" context super = %s", instanceKlass::cast(k)->external_name());
+ break;
+ case Change_new_impl:
+ if (!WizardMode)
+ ++nint;
+ else tty->print_cr(" context interface = %s", instanceKlass::cast(k)->external_name());
+ break;
+ }
+ }
+ if (nsup + nint != 0) {
+ tty->print_cr(" context supers = %d, interfaces = %d", nsup, nint);
+ }
+}
+
+#ifndef PRODUCT
+void Dependencies::print_statistics() {
+ if (deps_find_witness_print != 0) {
+ // Call one final time, to flush out the data.
+ deps_find_witness_print = -1;
+ count_find_witness_calls();
+ }
+}
+#endif