--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/interpreter/oopMapCache.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,602 @@
+/*
+ * Copyright (c) 1997, 2017, 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 "interpreter/oopMapCache.hpp"
+#include "logging/log.hpp"
+#include "logging/logStream.hpp"
+#include "memory/allocation.inline.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/signature.hpp"
+
+class OopMapCacheEntry: private InterpreterOopMap {
+ friend class InterpreterOopMap;
+ friend class OopMapForCacheEntry;
+ friend class OopMapCache;
+ friend class VerifyClosure;
+
+ private:
+ OopMapCacheEntry* _next;
+
+ protected:
+ // Initialization
+ void fill(const methodHandle& method, int bci);
+ // fills the bit mask for native calls
+ void fill_for_native(const methodHandle& method);
+ void set_mask(CellTypeState* vars, CellTypeState* stack, int stack_top);
+
+ // Deallocate bit masks and initialize fields
+ void flush();
+
+ private:
+ void allocate_bit_mask(); // allocates the bit mask on C heap f necessary
+ void deallocate_bit_mask(); // allocates the bit mask on C heap f necessary
+ bool verify_mask(CellTypeState *vars, CellTypeState *stack, int max_locals, int stack_top);
+
+ public:
+ OopMapCacheEntry() : InterpreterOopMap() {
+ _next = NULL;
+#ifdef ASSERT
+ _resource_allocate_bit_mask = false;
+#endif
+ }
+};
+
+
+// Implementation of OopMapForCacheEntry
+// (subclass of GenerateOopMap, initializes an OopMapCacheEntry for a given method and bci)
+
+class OopMapForCacheEntry: public GenerateOopMap {
+ OopMapCacheEntry *_entry;
+ int _bci;
+ int _stack_top;
+
+ virtual bool report_results() const { return false; }
+ virtual bool possible_gc_point (BytecodeStream *bcs);
+ virtual void fill_stackmap_prolog (int nof_gc_points);
+ virtual void fill_stackmap_epilog ();
+ virtual void fill_stackmap_for_opcodes (BytecodeStream *bcs,
+ CellTypeState* vars,
+ CellTypeState* stack,
+ int stack_top);
+ virtual void fill_init_vars (GrowableArray<intptr_t> *init_vars);
+
+ public:
+ OopMapForCacheEntry(const methodHandle& method, int bci, OopMapCacheEntry *entry);
+
+ // Computes stack map for (method,bci) and initialize entry
+ void compute_map(TRAPS);
+ int size();
+};
+
+
+OopMapForCacheEntry::OopMapForCacheEntry(const methodHandle& method, int bci, OopMapCacheEntry* entry) : GenerateOopMap(method) {
+ _bci = bci;
+ _entry = entry;
+ _stack_top = -1;
+}
+
+
+void OopMapForCacheEntry::compute_map(TRAPS) {
+ assert(!method()->is_native(), "cannot compute oop map for native methods");
+ // First check if it is a method where the stackmap is always empty
+ if (method()->code_size() == 0 || method()->max_locals() + method()->max_stack() == 0) {
+ _entry->set_mask_size(0);
+ } else {
+ ResourceMark rm;
+ GenerateOopMap::compute_map(CATCH);
+ result_for_basicblock(_bci);
+ }
+}
+
+
+bool OopMapForCacheEntry::possible_gc_point(BytecodeStream *bcs) {
+ return false; // We are not reporting any result. We call result_for_basicblock directly
+}
+
+
+void OopMapForCacheEntry::fill_stackmap_prolog(int nof_gc_points) {
+ // Do nothing
+}
+
+
+void OopMapForCacheEntry::fill_stackmap_epilog() {
+ // Do nothing
+}
+
+
+void OopMapForCacheEntry::fill_init_vars(GrowableArray<intptr_t> *init_vars) {
+ // Do nothing
+}
+
+
+void OopMapForCacheEntry::fill_stackmap_for_opcodes(BytecodeStream *bcs,
+ CellTypeState* vars,
+ CellTypeState* stack,
+ int stack_top) {
+ // Only interested in one specific bci
+ if (bcs->bci() == _bci) {
+ _entry->set_mask(vars, stack, stack_top);
+ _stack_top = stack_top;
+ }
+}
+
+
+int OopMapForCacheEntry::size() {
+ assert(_stack_top != -1, "compute_map must be called first");
+ return ((method()->is_static()) ? 0 : 1) + method()->max_locals() + _stack_top;
+}
+
+
+// Implementation of InterpreterOopMap and OopMapCacheEntry
+
+class VerifyClosure : public OffsetClosure {
+ private:
+ OopMapCacheEntry* _entry;
+ bool _failed;
+
+ public:
+ VerifyClosure(OopMapCacheEntry* entry) { _entry = entry; _failed = false; }
+ void offset_do(int offset) { if (!_entry->is_oop(offset)) _failed = true; }
+ bool failed() const { return _failed; }
+};
+
+InterpreterOopMap::InterpreterOopMap() {
+ initialize();
+#ifdef ASSERT
+ _resource_allocate_bit_mask = true;
+#endif
+}
+
+InterpreterOopMap::~InterpreterOopMap() {
+ // The expection is that the bit mask was allocated
+ // last in this resource area. That would make the free of the
+ // bit_mask effective (see how FREE_RESOURCE_ARRAY does a free).
+ // If it was not allocated last, there is not a correctness problem
+ // but the space for the bit_mask is not freed.
+ assert(_resource_allocate_bit_mask, "Trying to free C heap space");
+ if (mask_size() > small_mask_limit) {
+ FREE_RESOURCE_ARRAY(uintptr_t, _bit_mask[0], mask_word_size());
+ }
+}
+
+bool InterpreterOopMap::is_empty() const {
+ bool result = _method == NULL;
+ assert(_method != NULL || (_bci == 0 &&
+ (_mask_size == 0 || _mask_size == USHRT_MAX) &&
+ _bit_mask[0] == 0), "Should be completely empty");
+ return result;
+}
+
+void InterpreterOopMap::initialize() {
+ _method = NULL;
+ _mask_size = USHRT_MAX; // This value should cause a failure quickly
+ _bci = 0;
+ _expression_stack_size = 0;
+ for (int i = 0; i < N; i++) _bit_mask[i] = 0;
+}
+
+void InterpreterOopMap::iterate_oop(OffsetClosure* oop_closure) const {
+ int n = number_of_entries();
+ int word_index = 0;
+ uintptr_t value = 0;
+ uintptr_t mask = 0;
+ // iterate over entries
+ for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
+ // get current word
+ if (mask == 0) {
+ value = bit_mask()[word_index++];
+ mask = 1;
+ }
+ // test for oop
+ if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i);
+ }
+}
+
+void InterpreterOopMap::print() const {
+ int n = number_of_entries();
+ tty->print("oop map for ");
+ method()->print_value();
+ tty->print(" @ %d = [%d] { ", bci(), n);
+ for (int i = 0; i < n; i++) {
+ if (is_dead(i)) tty->print("%d+ ", i);
+ else
+ if (is_oop(i)) tty->print("%d ", i);
+ }
+ tty->print_cr("}");
+}
+
+class MaskFillerForNative: public NativeSignatureIterator {
+ private:
+ uintptr_t * _mask; // the bit mask to be filled
+ int _size; // the mask size in bits
+
+ void set_one(int i) {
+ i *= InterpreterOopMap::bits_per_entry;
+ assert(0 <= i && i < _size, "offset out of bounds");
+ _mask[i / BitsPerWord] |= (((uintptr_t) 1 << InterpreterOopMap::oop_bit_number) << (i % BitsPerWord));
+ }
+
+ public:
+ void pass_int() { /* ignore */ }
+ void pass_long() { /* ignore */ }
+ void pass_float() { /* ignore */ }
+ void pass_double() { /* ignore */ }
+ void pass_object() { set_one(offset()); }
+
+ MaskFillerForNative(const methodHandle& method, uintptr_t* mask, int size) : NativeSignatureIterator(method) {
+ _mask = mask;
+ _size = size;
+ // initialize with 0
+ int i = (size + BitsPerWord - 1) / BitsPerWord;
+ while (i-- > 0) _mask[i] = 0;
+ }
+
+ void generate() {
+ NativeSignatureIterator::iterate();
+ }
+};
+
+bool OopMapCacheEntry::verify_mask(CellTypeState* vars, CellTypeState* stack, int max_locals, int stack_top) {
+ // Check mask includes map
+ VerifyClosure blk(this);
+ iterate_oop(&blk);
+ if (blk.failed()) return false;
+
+ // Check if map is generated correctly
+ // (Use ?: operator to make sure all 'true' & 'false' are represented exactly the same so we can use == afterwards)
+ Log(interpreter, oopmap) logv;
+ LogStream st(logv.trace());
+
+ st.print("Locals (%d): ", max_locals);
+ for(int i = 0; i < max_locals; i++) {
+ bool v1 = is_oop(i) ? true : false;
+ bool v2 = vars[i].is_reference() ? true : false;
+ assert(v1 == v2, "locals oop mask generation error");
+ st.print("%d", v1 ? 1 : 0);
+ }
+ st.cr();
+
+ st.print("Stack (%d): ", stack_top);
+ for(int j = 0; j < stack_top; j++) {
+ bool v1 = is_oop(max_locals + j) ? true : false;
+ bool v2 = stack[j].is_reference() ? true : false;
+ assert(v1 == v2, "stack oop mask generation error");
+ st.print("%d", v1 ? 1 : 0);
+ }
+ st.cr();
+ return true;
+}
+
+void OopMapCacheEntry::allocate_bit_mask() {
+ if (mask_size() > small_mask_limit) {
+ assert(_bit_mask[0] == 0, "bit mask should be new or just flushed");
+ _bit_mask[0] = (intptr_t)
+ NEW_C_HEAP_ARRAY(uintptr_t, mask_word_size(), mtClass);
+ }
+}
+
+void OopMapCacheEntry::deallocate_bit_mask() {
+ if (mask_size() > small_mask_limit && _bit_mask[0] != 0) {
+ assert(!Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
+ "This bit mask should not be in the resource area");
+ FREE_C_HEAP_ARRAY(uintptr_t, _bit_mask[0]);
+ debug_only(_bit_mask[0] = 0;)
+ }
+}
+
+
+void OopMapCacheEntry::fill_for_native(const methodHandle& mh) {
+ assert(mh->is_native(), "method must be native method");
+ set_mask_size(mh->size_of_parameters() * bits_per_entry);
+ allocate_bit_mask();
+ // fill mask for parameters
+ MaskFillerForNative mf(mh, bit_mask(), mask_size());
+ mf.generate();
+}
+
+
+void OopMapCacheEntry::fill(const methodHandle& method, int bci) {
+ HandleMark hm;
+ // Flush entry to deallocate an existing entry
+ flush();
+ set_method(method());
+ set_bci(bci);
+ if (method->is_native()) {
+ // Native method activations have oops only among the parameters and one
+ // extra oop following the parameters (the mirror for static native methods).
+ fill_for_native(method);
+ } else {
+ EXCEPTION_MARK;
+ OopMapForCacheEntry gen(method, bci, this);
+ gen.compute_map(CATCH);
+ }
+}
+
+
+void OopMapCacheEntry::set_mask(CellTypeState *vars, CellTypeState *stack, int stack_top) {
+ // compute bit mask size
+ int max_locals = method()->max_locals();
+ int n_entries = max_locals + stack_top;
+ set_mask_size(n_entries * bits_per_entry);
+ allocate_bit_mask();
+ set_expression_stack_size(stack_top);
+
+ // compute bits
+ int word_index = 0;
+ uintptr_t value = 0;
+ uintptr_t mask = 1;
+
+ CellTypeState* cell = vars;
+ for (int entry_index = 0; entry_index < n_entries; entry_index++, mask <<= bits_per_entry, cell++) {
+ // store last word
+ if (mask == 0) {
+ bit_mask()[word_index++] = value;
+ value = 0;
+ mask = 1;
+ }
+
+ // switch to stack when done with locals
+ if (entry_index == max_locals) {
+ cell = stack;
+ }
+
+ // set oop bit
+ if ( cell->is_reference()) {
+ value |= (mask << oop_bit_number );
+ }
+
+ // set dead bit
+ if (!cell->is_live()) {
+ value |= (mask << dead_bit_number);
+ assert(!cell->is_reference(), "dead value marked as oop");
+ }
+ }
+
+ // make sure last word is stored
+ bit_mask()[word_index] = value;
+
+ // verify bit mask
+ assert(verify_mask(vars, stack, max_locals, stack_top), "mask could not be verified");
+}
+
+void OopMapCacheEntry::flush() {
+ deallocate_bit_mask();
+ initialize();
+}
+
+
+// Implementation of OopMapCache
+
+void InterpreterOopMap::resource_copy(OopMapCacheEntry* from) {
+ assert(_resource_allocate_bit_mask,
+ "Should not resource allocate the _bit_mask");
+
+ set_method(from->method());
+ set_bci(from->bci());
+ set_mask_size(from->mask_size());
+ set_expression_stack_size(from->expression_stack_size());
+
+ // Is the bit mask contained in the entry?
+ if (from->mask_size() <= small_mask_limit) {
+ memcpy((void *)_bit_mask, (void *)from->_bit_mask,
+ mask_word_size() * BytesPerWord);
+ } else {
+ // The expectation is that this InterpreterOopMap is a recently created
+ // and empty. It is used to get a copy of a cached entry.
+ // If the bit mask has a value, it should be in the
+ // resource area.
+ assert(_bit_mask[0] == 0 ||
+ Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
+ "The bit mask should have been allocated from a resource area");
+ // Allocate the bit_mask from a Resource area for performance. Allocating
+ // from the C heap as is done for OopMapCache has a significant
+ // performance impact.
+ _bit_mask[0] = (uintptr_t) NEW_RESOURCE_ARRAY(uintptr_t, mask_word_size());
+ assert(_bit_mask[0] != 0, "bit mask was not allocated");
+ memcpy((void*) _bit_mask[0], (void*) from->_bit_mask[0],
+ mask_word_size() * BytesPerWord);
+ }
+}
+
+inline unsigned int OopMapCache::hash_value_for(const methodHandle& method, int bci) const {
+ // We use method->code_size() rather than method->identity_hash() below since
+ // the mark may not be present if a pointer to the method is already reversed.
+ return ((unsigned int) bci)
+ ^ ((unsigned int) method->max_locals() << 2)
+ ^ ((unsigned int) method->code_size() << 4)
+ ^ ((unsigned int) method->size_of_parameters() << 6);
+}
+
+OopMapCacheEntry* volatile OopMapCache::_old_entries = NULL;
+
+OopMapCache::OopMapCache() {
+ _array = NEW_C_HEAP_ARRAY(OopMapCacheEntry*, _size, mtClass);
+ for(int i = 0; i < _size; i++) _array[i] = NULL;
+}
+
+
+OopMapCache::~OopMapCache() {
+ assert(_array != NULL, "sanity check");
+ // Deallocate oop maps that are allocated out-of-line
+ flush();
+ // Deallocate array
+ FREE_C_HEAP_ARRAY(OopMapCacheEntry*, _array);
+}
+
+OopMapCacheEntry* OopMapCache::entry_at(int i) const {
+ return (OopMapCacheEntry*)OrderAccess::load_ptr_acquire(&(_array[i % _size]));
+}
+
+bool OopMapCache::put_at(int i, OopMapCacheEntry* entry, OopMapCacheEntry* old) {
+ return Atomic::cmpxchg_ptr (entry, &_array[i % _size], old) == old;
+}
+
+void OopMapCache::flush() {
+ for (int i = 0; i < _size; i++) {
+ OopMapCacheEntry* entry = _array[i];
+ if (entry != NULL) {
+ _array[i] = NULL; // no barrier, only called in OopMapCache destructor
+ entry->flush();
+ FREE_C_HEAP_OBJ(entry);
+ }
+ }
+}
+
+void OopMapCache::flush_obsolete_entries() {
+ assert(SafepointSynchronize::is_at_safepoint(), "called by RedefineClasses in a safepoint");
+ for (int i = 0; i < _size; i++) {
+ OopMapCacheEntry* entry = _array[i];
+ if (entry != NULL && !entry->is_empty() && entry->method()->is_old()) {
+ // Cache entry is occupied by an old redefined method and we don't want
+ // to pin it down so flush the entry.
+ if (log_is_enabled(Debug, redefine, class, oopmap)) {
+ ResourceMark rm;
+ log_debug(redefine, class, interpreter, oopmap)
+ ("flush: %s(%s): cached entry @%d",
+ entry->method()->name()->as_C_string(), entry->method()->signature()->as_C_string(), i);
+ }
+ _array[i] = NULL;
+ entry->flush();
+ FREE_C_HEAP_OBJ(entry);
+ }
+ }
+}
+
+// Called by GC for thread root scan during a safepoint only. The other interpreted frame oopmaps
+// are generated locally and not cached.
+void OopMapCache::lookup(const methodHandle& method,
+ int bci,
+ InterpreterOopMap* entry_for) {
+ assert(SafepointSynchronize::is_at_safepoint(), "called by GC in a safepoint");
+ int probe = hash_value_for(method, bci);
+ int i;
+ OopMapCacheEntry* entry = NULL;
+
+ if (log_is_enabled(Debug, interpreter, oopmap)) {
+ static int count = 0;
+ ResourceMark rm;
+ log_debug(interpreter, oopmap)
+ ("%d - Computing oopmap at bci %d for %s at hash %d", ++count, bci,
+ method()->name_and_sig_as_C_string(), probe);
+ }
+
+ // Search hashtable for match
+ for(i = 0; i < _probe_depth; i++) {
+ entry = entry_at(probe + i);
+ if (entry != NULL && !entry->is_empty() && entry->match(method, bci)) {
+ entry_for->resource_copy(entry);
+ assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
+ log_debug(interpreter, oopmap)("- found at hash %d", probe + i);
+ return;
+ }
+ }
+
+ // Entry is not in hashtable.
+ // Compute entry
+
+ OopMapCacheEntry* tmp = NEW_C_HEAP_OBJ(OopMapCacheEntry, mtClass);
+ tmp->initialize();
+ tmp->fill(method, bci);
+ entry_for->resource_copy(tmp);
+
+ if (method->should_not_be_cached()) {
+ // It is either not safe or not a good idea to cache this Method*
+ // at this time. We give the caller of lookup() a copy of the
+ // interesting info via parameter entry_for, but we don't add it to
+ // the cache. See the gory details in Method*.cpp.
+ FREE_C_HEAP_OBJ(tmp);
+ return;
+ }
+
+ // First search for an empty slot
+ for(i = 0; i < _probe_depth; i++) {
+ entry = entry_at(probe + i);
+ if (entry == NULL) {
+ if (put_at(probe + i, tmp, NULL)) {
+ assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
+ return;
+ }
+ }
+ }
+
+ log_debug(interpreter, oopmap)("*** collision in oopmap cache - flushing item ***");
+
+ // No empty slot (uncommon case). Use (some approximation of a) LRU algorithm
+ // where the first entry in the collision array is replaced with the new one.
+ OopMapCacheEntry* old = entry_at(probe + 0);
+ if (put_at(probe + 0, tmp, old)) {
+ enqueue_for_cleanup(old);
+ } else {
+ enqueue_for_cleanup(tmp);
+ }
+
+ assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
+ return;
+}
+
+void OopMapCache::enqueue_for_cleanup(OopMapCacheEntry* entry) {
+ bool success = false;
+ OopMapCacheEntry* head;
+ do {
+ head = _old_entries;
+ entry->_next = head;
+ success = Atomic::cmpxchg_ptr (entry, &_old_entries, head) == head;
+ } while (!success);
+
+ if (log_is_enabled(Debug, interpreter, oopmap)) {
+ ResourceMark rm;
+ log_debug(interpreter, oopmap)("enqueue %s at bci %d for cleanup",
+ entry->method()->name_and_sig_as_C_string(), entry->bci());
+ }
+}
+
+// This is called after GC threads are done and nothing is accessing the old_entries
+// list, so no synchronization needed.
+void OopMapCache::cleanup_old_entries() {
+ OopMapCacheEntry* entry = _old_entries;
+ _old_entries = NULL;
+ while (entry != NULL) {
+ if (log_is_enabled(Debug, interpreter, oopmap)) {
+ ResourceMark rm;
+ log_debug(interpreter, oopmap)("cleanup entry %s at bci %d",
+ entry->method()->name_and_sig_as_C_string(), entry->bci());
+ }
+ OopMapCacheEntry* next = entry->_next;
+ entry->flush();
+ FREE_C_HEAP_OBJ(entry);
+ entry = next;
+ }
+}
+
+void OopMapCache::compute_one_oop_map(const methodHandle& method, int bci, InterpreterOopMap* entry) {
+ // Due to the invariants above it's tricky to allocate a temporary OopMapCacheEntry on the stack
+ OopMapCacheEntry* tmp = NEW_C_HEAP_ARRAY(OopMapCacheEntry, 1, mtClass);
+ tmp->initialize();
+ tmp->fill(method, bci);
+ entry->resource_copy(tmp);
+ FREE_C_HEAP_ARRAY(OopMapCacheEntry, tmp);
+}