--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/ci/ciMethodBlocks.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,405 @@
+/*
+ * Copyright (c) 2006, 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 "ci/ciMethodBlocks.hpp"
+#include "ci/ciStreams.hpp"
+#include "interpreter/bytecode.hpp"
+#include "utilities/copy.hpp"
+
+// ciMethodBlocks
+
+
+
+ciBlock *ciMethodBlocks::block_containing(int bci) {
+ ciBlock *blk = _bci_to_block[bci];
+ return blk;
+}
+
+bool ciMethodBlocks::is_block_start(int bci) {
+ assert(bci >=0 && bci < _code_size, "valid bytecode range");
+ ciBlock *b = _bci_to_block[bci];
+ assert(b != NULL, "must have block for bytecode");
+ return b->start_bci() == bci;
+}
+
+// ------------------------------------------------------------------
+// ciMethodBlocks::split_block_at
+//
+// Split the block spanning bci into two separate ranges. The former
+// block becomes the second half and a new range is created for the
+// first half. Returns the range beginning at bci.
+ciBlock *ciMethodBlocks::split_block_at(int bci) {
+ ciBlock *former_block = block_containing(bci);
+ ciBlock *new_block = new(_arena) ciBlock(_method, _num_blocks++, former_block->start_bci());
+ _blocks->append(new_block);
+ assert(former_block != NULL, "must not be NULL");
+ new_block->set_limit_bci(bci);
+ former_block->set_start_bci(bci);
+ for (int pos=bci-1; pos >= 0; pos--) {
+ ciBlock *current_block = block_containing(pos);
+ if (current_block == former_block) {
+ // Replace it.
+ _bci_to_block[pos] = new_block;
+ } else if (current_block == NULL) {
+ // Non-bytecode start. Skip.
+ continue;
+ } else {
+ // We are done with our backwards walk
+ break;
+ }
+ }
+ // Move an exception handler information if needed.
+ if (former_block->is_handler()) {
+ int ex_start = former_block->ex_start_bci();
+ int ex_end = former_block->ex_limit_bci();
+ new_block->set_exception_range(ex_start, ex_end);
+ // Clear information in former_block.
+ former_block->clear_exception_handler();
+ }
+ return former_block;
+}
+
+ciBlock *ciMethodBlocks::make_block_at(int bci) {
+ ciBlock *cb = block_containing(bci);
+ if (cb == NULL ) {
+ // This is our first time visiting this bytecode. Create
+ // a fresh block and assign it this starting point.
+ ciBlock *nb = new(_arena) ciBlock(_method, _num_blocks++, bci);
+ _blocks->append(nb);
+ _bci_to_block[bci] = nb;
+ return nb;
+ } else if (cb->start_bci() == bci) {
+ // The block begins at bci. Simply return it.
+ return cb;
+ } else {
+ // We have already created a block containing bci but
+ // not starting at bci. This existing block needs to
+ // be split into two.
+ return split_block_at(bci);
+ }
+}
+
+ciBlock *ciMethodBlocks::make_dummy_block() {
+ ciBlock *dum = new(_arena) ciBlock(_method, -1, 0);
+ return dum;
+}
+
+void ciMethodBlocks::do_analysis() {
+ ciBytecodeStream s(_method);
+ ciBlock *cur_block = block_containing(0);
+ int limit_bci = _method->code_size();
+
+ while (s.next() != ciBytecodeStream::EOBC()) {
+ int bci = s.cur_bci();
+ // Determine if a new block has been made at the current bci. If
+ // this block differs from our current range, switch to the new
+ // one and end the old one.
+ assert(cur_block != NULL, "must always have a current block");
+ ciBlock *new_block = block_containing(bci);
+ if (new_block == NULL || new_block == cur_block) {
+ // We have not marked this bci as the start of a new block.
+ // Keep interpreting the current_range.
+ _bci_to_block[bci] = cur_block;
+ } else {
+ cur_block->set_limit_bci(bci);
+ cur_block = new_block;
+ }
+
+ switch (s.cur_bc()) {
+ case Bytecodes::_ifeq :
+ case Bytecodes::_ifne :
+ case Bytecodes::_iflt :
+ case Bytecodes::_ifge :
+ case Bytecodes::_ifgt :
+ case Bytecodes::_ifle :
+ case Bytecodes::_if_icmpeq :
+ case Bytecodes::_if_icmpne :
+ case Bytecodes::_if_icmplt :
+ case Bytecodes::_if_icmpge :
+ case Bytecodes::_if_icmpgt :
+ case Bytecodes::_if_icmple :
+ case Bytecodes::_if_acmpeq :
+ case Bytecodes::_if_acmpne :
+ case Bytecodes::_ifnull :
+ case Bytecodes::_ifnonnull :
+ {
+ cur_block->set_control_bci(bci);
+ ciBlock *fall_through = make_block_at(s.next_bci());
+ int dest_bci = s.get_dest();
+ ciBlock *dest = make_block_at(dest_bci);
+ break;
+ }
+
+ case Bytecodes::_goto :
+ {
+ cur_block->set_control_bci(bci);
+ if (s.next_bci() < limit_bci) {
+ (void) make_block_at(s.next_bci());
+ }
+ int dest_bci = s.get_dest();
+ ciBlock *dest = make_block_at(dest_bci);
+ break;
+ }
+
+ case Bytecodes::_jsr :
+ {
+ cur_block->set_control_bci(bci);
+ ciBlock *ret = make_block_at(s.next_bci());
+ int dest_bci = s.get_dest();
+ ciBlock *dest = make_block_at(dest_bci);
+ break;
+ }
+
+ case Bytecodes::_tableswitch :
+ {
+ cur_block->set_control_bci(bci);
+ Bytecode_tableswitch sw(&s);
+ int len = sw.length();
+ ciBlock *dest;
+ int dest_bci;
+ for (int i = 0; i < len; i++) {
+ dest_bci = s.cur_bci() + sw.dest_offset_at(i);
+ dest = make_block_at(dest_bci);
+ }
+ dest_bci = s.cur_bci() + sw.default_offset();
+ make_block_at(dest_bci);
+ if (s.next_bci() < limit_bci) {
+ dest = make_block_at(s.next_bci());
+ }
+ }
+ break;
+
+ case Bytecodes::_lookupswitch:
+ {
+ cur_block->set_control_bci(bci);
+ Bytecode_lookupswitch sw(&s);
+ int len = sw.number_of_pairs();
+ ciBlock *dest;
+ int dest_bci;
+ for (int i = 0; i < len; i++) {
+ dest_bci = s.cur_bci() + sw.pair_at(i).offset();
+ dest = make_block_at(dest_bci);
+ }
+ dest_bci = s.cur_bci() + sw.default_offset();
+ dest = make_block_at(dest_bci);
+ if (s.next_bci() < limit_bci) {
+ dest = make_block_at(s.next_bci());
+ }
+ }
+ break;
+
+ case Bytecodes::_goto_w :
+ {
+ cur_block->set_control_bci(bci);
+ if (s.next_bci() < limit_bci) {
+ (void) make_block_at(s.next_bci());
+ }
+ int dest_bci = s.get_far_dest();
+ ciBlock *dest = make_block_at(dest_bci);
+ break;
+ }
+
+ case Bytecodes::_jsr_w :
+ {
+ cur_block->set_control_bci(bci);
+ ciBlock *ret = make_block_at(s.next_bci());
+ int dest_bci = s.get_far_dest();
+ ciBlock *dest = make_block_at(dest_bci);
+ break;
+ }
+
+ case Bytecodes::_athrow :
+ cur_block->set_may_throw();
+ // fall-through
+ case Bytecodes::_ret :
+ case Bytecodes::_ireturn :
+ case Bytecodes::_lreturn :
+ case Bytecodes::_freturn :
+ case Bytecodes::_dreturn :
+ case Bytecodes::_areturn :
+ case Bytecodes::_return :
+ cur_block->set_control_bci(bci);
+ if (s.next_bci() < limit_bci) {
+ (void) make_block_at(s.next_bci());
+ }
+ break;
+
+ default:
+ break;
+ }
+ }
+ // End the last block
+ cur_block->set_limit_bci(limit_bci);
+}
+
+ciMethodBlocks::ciMethodBlocks(Arena *arena, ciMethod *meth): _method(meth),
+ _arena(arena), _num_blocks(0), _code_size(meth->code_size()) {
+ int block_estimate = _code_size / 8;
+
+ _blocks = new(_arena) GrowableArray<ciBlock *>(_arena, block_estimate, 0, NULL);
+ int b2bsize = _code_size * sizeof(ciBlock **);
+ _bci_to_block = (ciBlock **) arena->Amalloc(b2bsize);
+ Copy::zero_to_words((HeapWord*) _bci_to_block, b2bsize / sizeof(HeapWord));
+
+ // create initial block covering the entire method
+ ciBlock *b = new(arena) ciBlock(_method, _num_blocks++, 0);
+ _blocks->append(b);
+ _bci_to_block[0] = b;
+
+ // create blocks for exception handlers
+ if (meth->has_exception_handlers()) {
+ for(ciExceptionHandlerStream str(meth); !str.is_done(); str.next()) {
+ ciExceptionHandler* handler = str.handler();
+ ciBlock *eb = make_block_at(handler->handler_bci());
+ //
+ // Several exception handlers can have the same handler_bci:
+ //
+ // try {
+ // if (a.foo(b) < 0) {
+ // return a.error();
+ // }
+ // return CoderResult.UNDERFLOW;
+ // } finally {
+ // a.position(b);
+ // }
+ //
+ // The try block above is divided into 2 exception blocks
+ // separated by 'areturn' bci.
+ //
+ int ex_start = handler->start();
+ int ex_end = handler->limit();
+ // ensure a block at the start of exception range and start of following code
+ (void) make_block_at(ex_start);
+ if (ex_end < _code_size)
+ (void) make_block_at(ex_end);
+
+ if (eb->is_handler()) {
+ // Extend old handler exception range to cover additional range.
+ int old_ex_start = eb->ex_start_bci();
+ int old_ex_end = eb->ex_limit_bci();
+ if (ex_start > old_ex_start)
+ ex_start = old_ex_start;
+ if (ex_end < old_ex_end)
+ ex_end = old_ex_end;
+ eb->clear_exception_handler(); // Reset exception information
+ }
+ eb->set_exception_range(ex_start, ex_end);
+ }
+ }
+
+ // scan the bytecodes and identify blocks
+ do_analysis();
+
+ // mark blocks that have exception handlers
+ if (meth->has_exception_handlers()) {
+ for(ciExceptionHandlerStream str(meth); !str.is_done(); str.next()) {
+ ciExceptionHandler* handler = str.handler();
+ int ex_start = handler->start();
+ int ex_end = handler->limit();
+
+ int bci = ex_start;
+ while (bci < ex_end) {
+ ciBlock *b = block_containing(bci);
+ b->set_has_handler();
+ bci = b->limit_bci();
+ }
+ }
+ }
+}
+
+void ciMethodBlocks::clear_processed() {
+ for (int i = 0; i < _blocks->length(); i++)
+ _blocks->at(i)->clear_processed();
+}
+
+#ifndef PRODUCT
+void ciMethodBlocks::dump() {
+ tty->print("---- blocks for method: ");
+ _method->print();
+ tty->cr();
+ for (int i = 0; i < _blocks->length(); i++) {
+ tty->print(" B%d: ", i); _blocks->at(i)->dump();
+ }
+}
+#endif
+
+
+ciBlock::ciBlock(ciMethod *method, int index, int start_bci) :
+#ifndef PRODUCT
+ _method(method),
+#endif
+ _idx(index), _flags(0), _start_bci(start_bci), _limit_bci(-1), _control_bci(fall_through_bci),
+ _ex_start_bci(-1), _ex_limit_bci(-1) {
+}
+
+void ciBlock::set_exception_range(int start_bci, int limit_bci) {
+ assert(limit_bci >= start_bci, "valid range");
+ assert(!is_handler() && _ex_start_bci == -1 && _ex_limit_bci == -1, "must not be handler");
+ _ex_start_bci = start_bci;
+ _ex_limit_bci = limit_bci;
+ set_handler();
+}
+
+#ifndef PRODUCT
+static const char *flagnames[] = {
+ "Processed",
+ "Handler",
+ "MayThrow",
+ "Jsr",
+ "Ret",
+ "RetTarget",
+ "HasHandler",
+};
+
+void ciBlock::dump() {
+ tty->print(" [%d .. %d), {", _start_bci, _limit_bci);
+ for (int i = 0; i < 7; i++) {
+ if ((_flags & (1 << i)) != 0) {
+ tty->print(" %s", flagnames[i]);
+ }
+ }
+ tty->print(" ]");
+ if (is_handler())
+ tty->print(" handles(%d..%d)", _ex_start_bci, _ex_limit_bci);
+ tty->cr();
+}
+
+// ------------------------------------------------------------------
+// ciBlock::print_on
+void ciBlock::print_on(outputStream* st) const {
+ st->print_cr("--------------------------------------------------------");
+ st->print ("ciBlock [%d - %d) control : ", start_bci(), limit_bci());
+ if (control_bci() == fall_through_bci) {
+ st->print_cr("%d:fall through", limit_bci());
+ } else {
+ st->print_cr("%d:%s", control_bci(),
+ Bytecodes::name(method()->java_code_at_bci(control_bci())));
+ }
+
+ if (Verbose || WizardMode) {
+ method()->print_codes_on(start_bci(), limit_bci(), st);
+ }
+}
+#endif