/* * Copyright (c) 2005, 2015, 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/bcEscapeAnalyzer.hpp" #include "ci/ciConstant.hpp" #include "ci/ciField.hpp" #include "ci/ciMethodBlocks.hpp" #include "ci/ciStreams.hpp" #include "interpreter/bytecode.hpp" #include "oops/oop.inline.hpp" #include "utilities/bitMap.inline.hpp" #ifndef PRODUCT #define TRACE_BCEA(level, code) \ if (EstimateArgEscape && BCEATraceLevel >= level) { \ code; \ } #else #define TRACE_BCEA(level, code) #endif // Maintain a map of which arguments a local variable or // stack slot may contain. In addition to tracking // arguments, it tracks two special values, "allocated" // which represents any object allocated in the current // method, and "unknown" which is any other object. // Up to 30 arguments are handled, with the last one // representing summary information for any extra arguments class BCEscapeAnalyzer::ArgumentMap { uint _bits; enum {MAXBIT = 29, ALLOCATED = 1, UNKNOWN = 2}; uint int_to_bit(uint e) const { if (e > MAXBIT) e = MAXBIT; return (1 << (e + 2)); } public: ArgumentMap() { _bits = 0;} void set_bits(uint bits) { _bits = bits;} uint get_bits() const { return _bits;} void clear() { _bits = 0;} void set_all() { _bits = ~0u; } bool is_empty() const { return _bits == 0; } bool contains(uint var) const { return (_bits & int_to_bit(var)) != 0; } bool is_singleton(uint var) const { return (_bits == int_to_bit(var)); } bool contains_unknown() const { return (_bits & UNKNOWN) != 0; } bool contains_allocated() const { return (_bits & ALLOCATED) != 0; } bool contains_vars() const { return (_bits & (((1 << MAXBIT) -1) << 2)) != 0; } void set(uint var) { _bits = int_to_bit(var); } void add(uint var) { _bits |= int_to_bit(var); } void add_unknown() { _bits = UNKNOWN; } void add_allocated() { _bits = ALLOCATED; } void set_union(const ArgumentMap &am) { _bits |= am._bits; } void set_intersect(const ArgumentMap &am) { _bits |= am._bits; } void set_difference(const ArgumentMap &am) { _bits &= ~am._bits; } void operator=(const ArgumentMap &am) { _bits = am._bits; } bool operator==(const ArgumentMap &am) { return _bits == am._bits; } bool operator!=(const ArgumentMap &am) { return _bits != am._bits; } }; class BCEscapeAnalyzer::StateInfo { public: ArgumentMap *_vars; ArgumentMap *_stack; int _stack_height; int _max_stack; bool _initialized; ArgumentMap empty_map; StateInfo() { empty_map.clear(); } ArgumentMap raw_pop() { guarantee(_stack_height > 0, "stack underflow"); return _stack[--_stack_height]; } ArgumentMap apop() { return raw_pop(); } void spop() { raw_pop(); } void lpop() { spop(); spop(); } void raw_push(ArgumentMap i) { guarantee(_stack_height < _max_stack, "stack overflow"); _stack[_stack_height++] = i; } void apush(ArgumentMap i) { raw_push(i); } void spush() { raw_push(empty_map); } void lpush() { spush(); spush(); } }; void BCEscapeAnalyzer::set_returned(ArgumentMap vars) { for (int i = 0; i < _arg_size; i++) { if (vars.contains(i)) _arg_returned.set(i); } _return_local = _return_local && !(vars.contains_unknown() || vars.contains_allocated()); _return_allocated = _return_allocated && vars.contains_allocated() && !(vars.contains_unknown() || vars.contains_vars()); } // return true if any element of vars is an argument bool BCEscapeAnalyzer::is_argument(ArgumentMap vars) { for (int i = 0; i < _arg_size; i++) { if (vars.contains(i)) return true; } return false; } // return true if any element of vars is an arg_stack argument bool BCEscapeAnalyzer::is_arg_stack(ArgumentMap vars){ if (_conservative) return true; for (int i = 0; i < _arg_size; i++) { if (vars.contains(i) && _arg_stack.test(i)) return true; } return false; } // return true if all argument elements of vars are returned bool BCEscapeAnalyzer::returns_all(ArgumentMap vars) { for (int i = 0; i < _arg_size; i++) { if (vars.contains(i) && !_arg_returned.test(i)) { return false; } } return true; } void BCEscapeAnalyzer::clear_bits(ArgumentMap vars, VectorSet &bm) { for (int i = 0; i < _arg_size; i++) { if (vars.contains(i)) { bm >>= i; } } } void BCEscapeAnalyzer::set_method_escape(ArgumentMap vars) { clear_bits(vars, _arg_local); if (vars.contains_allocated()) { _allocated_escapes = true; } } void BCEscapeAnalyzer::set_global_escape(ArgumentMap vars, bool merge) { clear_bits(vars, _arg_local); clear_bits(vars, _arg_stack); if (vars.contains_allocated()) _allocated_escapes = true; if (merge && !vars.is_empty()) { // Merge new state into already processed block. // New state is not taken into account and // it may invalidate set_returned() result. if (vars.contains_unknown() || vars.contains_allocated()) { _return_local = false; } if (vars.contains_unknown() || vars.contains_vars()) { _return_allocated = false; } if (_return_local && vars.contains_vars() && !returns_all(vars)) { // Return result should be invalidated if args in new // state are not recorded in return state. _return_local = false; } } } void BCEscapeAnalyzer::set_dirty(ArgumentMap vars) { clear_bits(vars, _dirty); } void BCEscapeAnalyzer::set_modified(ArgumentMap vars, int offs, int size) { for (int i = 0; i < _arg_size; i++) { if (vars.contains(i)) { set_arg_modified(i, offs, size); } } if (vars.contains_unknown()) _unknown_modified = true; } bool BCEscapeAnalyzer::is_recursive_call(ciMethod* callee) { for (BCEscapeAnalyzer* scope = this; scope != NULL; scope = scope->_parent) { if (scope->method() == callee) { return true; } } return false; } bool BCEscapeAnalyzer::is_arg_modified(int arg, int offset, int size_in_bytes) { if (offset == OFFSET_ANY) return _arg_modified[arg] != 0; assert(arg >= 0 && arg < _arg_size, "must be an argument."); bool modified = false; int l = offset / HeapWordSize; int h = round_to(offset + size_in_bytes, HeapWordSize) / HeapWordSize; if (l > ARG_OFFSET_MAX) l = ARG_OFFSET_MAX; if (h > ARG_OFFSET_MAX+1) h = ARG_OFFSET_MAX + 1; for (int i = l; i < h; i++) { modified = modified || (_arg_modified[arg] & (1 << i)) != 0; } return modified; } void BCEscapeAnalyzer::set_arg_modified(int arg, int offset, int size_in_bytes) { if (offset == OFFSET_ANY) { _arg_modified[arg] = (uint) -1; return; } assert(arg >= 0 && arg < _arg_size, "must be an argument."); int l = offset / HeapWordSize; int h = round_to(offset + size_in_bytes, HeapWordSize) / HeapWordSize; if (l > ARG_OFFSET_MAX) l = ARG_OFFSET_MAX; if (h > ARG_OFFSET_MAX+1) h = ARG_OFFSET_MAX + 1; for (int i = l; i < h; i++) { _arg_modified[arg] |= (1 << i); } } void BCEscapeAnalyzer::invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder) { int i; // retrieve information about the callee ciInstanceKlass* klass = target->holder(); ciInstanceKlass* calling_klass = method()->holder(); ciInstanceKlass* callee_holder = ciEnv::get_instance_klass_for_declared_method_holder(holder); ciInstanceKlass* actual_recv = callee_holder; // Some methods are obviously bindable without any type checks so // convert them directly to an invokespecial or invokestatic. if (target->is_loaded() && !target->is_abstract() && target->can_be_statically_bound()) { switch (code) { case Bytecodes::_invokevirtual: code = Bytecodes::_invokespecial; break; case Bytecodes::_invokehandle: code = target->is_static() ? Bytecodes::_invokestatic : Bytecodes::_invokespecial; break; } } // compute size of arguments int arg_size = target->invoke_arg_size(code); int arg_base = MAX2(state._stack_height - arg_size, 0); // direct recursive calls are skipped if they can be bound statically without introducing // dependencies and if parameters are passed at the same position as in the current method // other calls are skipped if there are no unescaped arguments passed to them bool directly_recursive = (method() == target) && (code != Bytecodes::_invokevirtual || target->is_final_method() || state._stack[arg_base] .is_empty()); // check if analysis of callee can safely be skipped bool skip_callee = true; for (i = state._stack_height - 1; i >= arg_base && skip_callee; i--) { ArgumentMap arg = state._stack[i]; skip_callee = !is_argument(arg) || !is_arg_stack(arg) || (directly_recursive && arg.is_singleton(i - arg_base)); } // For now we conservatively skip invokedynamic. if (code == Bytecodes::_invokedynamic) { skip_callee = true; } if (skip_callee) { TRACE_BCEA(3, tty->print_cr("[EA] skipping method %s::%s", holder->name()->as_utf8(), target->name()->as_utf8())); for (i = 0; i < arg_size; i++) { set_method_escape(state.raw_pop()); } _unknown_modified = true; // assume the worst since we don't analyze the called method return; } // determine actual method (use CHA if necessary) ciMethod* inline_target = NULL; if (target->is_loaded() && klass->is_loaded() && (klass->is_initialized() || klass->is_interface() && target->holder()->is_initialized()) && target->is_loaded()) { if (code == Bytecodes::_invokestatic || code == Bytecodes::_invokespecial || code == Bytecodes::_invokevirtual && target->is_final_method()) { inline_target = target; } else { inline_target = target->find_monomorphic_target(calling_klass, callee_holder, actual_recv); } } if (inline_target != NULL && !is_recursive_call(inline_target)) { // analyze callee BCEscapeAnalyzer analyzer(inline_target, this); // adjust escape state of actual parameters bool must_record_dependencies = false; for (i = arg_size - 1; i >= 0; i--) { ArgumentMap arg = state.raw_pop(); // Check if callee arg is a caller arg or an allocated object bool allocated = arg.contains_allocated(); if (!(is_argument(arg) || allocated)) continue; for (int j = 0; j < _arg_size; j++) { if (arg.contains(j)) { _arg_modified[j] |= analyzer._arg_modified[i]; } } if (!(is_arg_stack(arg) || allocated)) { // arguments have already been recognized as escaping } else if (analyzer.is_arg_stack(i) && !analyzer.is_arg_returned(i)) { set_method_escape(arg); must_record_dependencies = true; } else { set_global_escape(arg); } } _unknown_modified = _unknown_modified || analyzer.has_non_arg_side_affects(); // record dependencies if at least one parameter retained stack-allocatable if (must_record_dependencies) { if (code == Bytecodes::_invokeinterface || code == Bytecodes::_invokevirtual && !target->is_final_method()) { _dependencies.append(actual_recv); _dependencies.append(inline_target); } _dependencies.appendAll(analyzer.dependencies()); } } else { TRACE_BCEA(1, tty->print_cr("[EA] virtual method %s is not monomorphic.", target->name()->as_utf8())); // conservatively mark all actual parameters as escaping globally for (i = 0; i < arg_size; i++) { ArgumentMap arg = state.raw_pop(); if (!is_argument(arg)) continue; set_modified(arg, OFFSET_ANY, type2size[T_INT]*HeapWordSize); set_global_escape(arg); } _unknown_modified = true; // assume the worst since we don't know the called method } } bool BCEscapeAnalyzer::contains(uint arg_set1, uint arg_set2) { return ((~arg_set1) | arg_set2) == 0; } void BCEscapeAnalyzer::iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray &successors) { blk->set_processed(); ciBytecodeStream s(method()); int limit_bci = blk->limit_bci(); bool fall_through = false; ArgumentMap allocated_obj; allocated_obj.add_allocated(); ArgumentMap unknown_obj; unknown_obj.add_unknown(); ArgumentMap empty_map; s.reset_to_bci(blk->start_bci()); while (s.next() != ciBytecodeStream::EOBC() && s.cur_bci() < limit_bci) { fall_through = true; switch (s.cur_bc()) { case Bytecodes::_nop: break; case Bytecodes::_aconst_null: state.apush(unknown_obj); break; case Bytecodes::_iconst_m1: case Bytecodes::_iconst_0: case Bytecodes::_iconst_1: case Bytecodes::_iconst_2: case Bytecodes::_iconst_3: case Bytecodes::_iconst_4: case Bytecodes::_iconst_5: case Bytecodes::_fconst_0: case Bytecodes::_fconst_1: case Bytecodes::_fconst_2: case Bytecodes::_bipush: case Bytecodes::_sipush: state.spush(); break; case Bytecodes::_lconst_0: case Bytecodes::_lconst_1: case Bytecodes::_dconst_0: case Bytecodes::_dconst_1: state.lpush(); break; case Bytecodes::_ldc: case Bytecodes::_ldc_w: case Bytecodes::_ldc2_w: { // Avoid calling get_constant() which will try to allocate // unloaded constant. We need only constant's type. int index = s.get_constant_pool_index(); constantTag tag = s.get_constant_pool_tag(index); if (tag.is_long() || tag.is_double()) { // Only longs and doubles use 2 stack slots. state.lpush(); } else if (tag.basic_type() == T_OBJECT) { state.apush(unknown_obj); } else { state.spush(); } break; } case Bytecodes::_aload: state.apush(state._vars[s.get_index()]); break; case Bytecodes::_iload: case Bytecodes::_fload: case Bytecodes::_iload_0: case Bytecodes::_iload_1: case Bytecodes::_iload_2: case Bytecodes::_iload_3: case Bytecodes::_fload_0: case Bytecodes::_fload_1: case Bytecodes::_fload_2: case Bytecodes::_fload_3: state.spush(); break; case Bytecodes::_lload: case Bytecodes::_dload: case Bytecodes::_lload_0: case Bytecodes::_lload_1: case Bytecodes::_lload_2: case Bytecodes::_lload_3: case Bytecodes::_dload_0: case Bytecodes::_dload_1: case Bytecodes::_dload_2: case Bytecodes::_dload_3: state.lpush(); break; case Bytecodes::_aload_0: state.apush(state._vars[0]); break; case Bytecodes::_aload_1: state.apush(state._vars[1]); break; case Bytecodes::_aload_2: state.apush(state._vars[2]); break; case Bytecodes::_aload_3: state.apush(state._vars[3]); break; case Bytecodes::_iaload: case Bytecodes::_faload: case Bytecodes::_baload: case Bytecodes::_caload: case Bytecodes::_saload: state.spop(); set_method_escape(state.apop()); state.spush(); break; case Bytecodes::_laload: case Bytecodes::_daload: state.spop(); set_method_escape(state.apop()); state.lpush(); break; case Bytecodes::_aaload: { state.spop(); ArgumentMap array = state.apop(); set_method_escape(array); state.apush(unknown_obj); set_dirty(array); } break; case Bytecodes::_istore: case Bytecodes::_fstore: case Bytecodes::_istore_0: case Bytecodes::_istore_1: case Bytecodes::_istore_2: case Bytecodes::_istore_3: case Bytecodes::_fstore_0: case Bytecodes::_fstore_1: case Bytecodes::_fstore_2: case Bytecodes::_fstore_3: state.spop(); break; case Bytecodes::_lstore: case Bytecodes::_dstore: case Bytecodes::_lstore_0: case Bytecodes::_lstore_1: case Bytecodes::_lstore_2: case Bytecodes::_lstore_3: case Bytecodes::_dstore_0: case Bytecodes::_dstore_1: case Bytecodes::_dstore_2: case Bytecodes::_dstore_3: state.lpop(); break; case Bytecodes::_astore: state._vars[s.get_index()] = state.apop(); break; case Bytecodes::_astore_0: state._vars[0] = state.apop(); break; case Bytecodes::_astore_1: state._vars[1] = state.apop(); break; case Bytecodes::_astore_2: state._vars[2] = state.apop(); break; case Bytecodes::_astore_3: state._vars[3] = state.apop(); break; case Bytecodes::_iastore: case Bytecodes::_fastore: case Bytecodes::_bastore: case Bytecodes::_castore: case Bytecodes::_sastore: { state.spop(); state.spop(); ArgumentMap arr = state.apop(); set_method_escape(arr); set_modified(arr, OFFSET_ANY, type2size[T_INT]*HeapWordSize); break; } case Bytecodes::_lastore: case Bytecodes::_dastore: { state.lpop(); state.spop(); ArgumentMap arr = state.apop(); set_method_escape(arr); set_modified(arr, OFFSET_ANY, type2size[T_LONG]*HeapWordSize); break; } case Bytecodes::_aastore: { set_global_escape(state.apop()); state.spop(); ArgumentMap arr = state.apop(); set_modified(arr, OFFSET_ANY, type2size[T_OBJECT]*HeapWordSize); break; } case Bytecodes::_pop: state.raw_pop(); break; case Bytecodes::_pop2: state.raw_pop(); state.raw_pop(); break; case Bytecodes::_dup: { ArgumentMap w1 = state.raw_pop(); state.raw_push(w1); state.raw_push(w1); } break; case Bytecodes::_dup_x1: { ArgumentMap w1 = state.raw_pop(); ArgumentMap w2 = state.raw_pop(); state.raw_push(w1); state.raw_push(w2); state.raw_push(w1); } break; case Bytecodes::_dup_x2: { ArgumentMap w1 = state.raw_pop(); ArgumentMap w2 = state.raw_pop(); ArgumentMap w3 = state.raw_pop(); state.raw_push(w1); state.raw_push(w3); state.raw_push(w2); state.raw_push(w1); } break; case Bytecodes::_dup2: { ArgumentMap w1 = state.raw_pop(); ArgumentMap w2 = state.raw_pop(); state.raw_push(w2); state.raw_push(w1); state.raw_push(w2); state.raw_push(w1); } break; case Bytecodes::_dup2_x1: { ArgumentMap w1 = state.raw_pop(); ArgumentMap w2 = state.raw_pop(); ArgumentMap w3 = state.raw_pop(); state.raw_push(w2); state.raw_push(w1); state.raw_push(w3); state.raw_push(w2); state.raw_push(w1); } break; case Bytecodes::_dup2_x2: { ArgumentMap w1 = state.raw_pop(); ArgumentMap w2 = state.raw_pop(); ArgumentMap w3 = state.raw_pop(); ArgumentMap w4 = state.raw_pop(); state.raw_push(w2); state.raw_push(w1); state.raw_push(w4); state.raw_push(w3); state.raw_push(w2); state.raw_push(w1); } break; case Bytecodes::_swap: { ArgumentMap w1 = state.raw_pop(); ArgumentMap w2 = state.raw_pop(); state.raw_push(w1); state.raw_push(w2); } break; case Bytecodes::_iadd: case Bytecodes::_fadd: case Bytecodes::_isub: case Bytecodes::_fsub: case Bytecodes::_imul: case Bytecodes::_fmul: case Bytecodes::_idiv: case Bytecodes::_fdiv: case Bytecodes::_irem: case Bytecodes::_frem: case Bytecodes::_iand: case Bytecodes::_ior: case Bytecodes::_ixor: state.spop(); state.spop(); state.spush(); break; case Bytecodes::_ladd: case Bytecodes::_dadd: case Bytecodes::_lsub: case Bytecodes::_dsub: case Bytecodes::_lmul: case Bytecodes::_dmul: case Bytecodes::_ldiv: case Bytecodes::_ddiv: case Bytecodes::_lrem: case Bytecodes::_drem: case Bytecodes::_land: case Bytecodes::_lor: case Bytecodes::_lxor: state.lpop(); state.lpop(); state.lpush(); break; case Bytecodes::_ishl: case Bytecodes::_ishr: case Bytecodes::_iushr: state.spop(); state.spop(); state.spush(); break; case Bytecodes::_lshl: case Bytecodes::_lshr: case Bytecodes::_lushr: state.spop(); state.lpop(); state.lpush(); break; case Bytecodes::_ineg: case Bytecodes::_fneg: state.spop(); state.spush(); break; case Bytecodes::_lneg: case Bytecodes::_dneg: state.lpop(); state.lpush(); break; case Bytecodes::_iinc: break; case Bytecodes::_i2l: case Bytecodes::_i2d: case Bytecodes::_f2l: case Bytecodes::_f2d: state.spop(); state.lpush(); break; case Bytecodes::_i2f: case Bytecodes::_f2i: state.spop(); state.spush(); break; case Bytecodes::_l2i: case Bytecodes::_l2f: case Bytecodes::_d2i: case Bytecodes::_d2f: state.lpop(); state.spush(); break; case Bytecodes::_l2d: case Bytecodes::_d2l: state.lpop(); state.lpush(); break; case Bytecodes::_i2b: case Bytecodes::_i2c: case Bytecodes::_i2s: state.spop(); state.spush(); break; case Bytecodes::_lcmp: case Bytecodes::_dcmpl: case Bytecodes::_dcmpg: state.lpop(); state.lpop(); state.spush(); break; case Bytecodes::_fcmpl: case Bytecodes::_fcmpg: state.spop(); state.spop(); state.spush(); break; case Bytecodes::_ifeq: case Bytecodes::_ifne: case Bytecodes::_iflt: case Bytecodes::_ifge: case Bytecodes::_ifgt: case Bytecodes::_ifle: { state.spop(); int dest_bci = s.get_dest(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); assert(s.next_bci() == limit_bci, "branch must end block"); successors.push(_methodBlocks->block_containing(dest_bci)); break; } case Bytecodes::_if_icmpeq: case Bytecodes::_if_icmpne: case Bytecodes::_if_icmplt: case Bytecodes::_if_icmpge: case Bytecodes::_if_icmpgt: case Bytecodes::_if_icmple: { state.spop(); state.spop(); int dest_bci = s.get_dest(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); assert(s.next_bci() == limit_bci, "branch must end block"); successors.push(_methodBlocks->block_containing(dest_bci)); break; } case Bytecodes::_if_acmpeq: case Bytecodes::_if_acmpne: { set_method_escape(state.apop()); set_method_escape(state.apop()); int dest_bci = s.get_dest(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); assert(s.next_bci() == limit_bci, "branch must end block"); successors.push(_methodBlocks->block_containing(dest_bci)); break; } case Bytecodes::_goto: { int dest_bci = s.get_dest(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); assert(s.next_bci() == limit_bci, "branch must end block"); successors.push(_methodBlocks->block_containing(dest_bci)); fall_through = false; break; } case Bytecodes::_jsr: { int dest_bci = s.get_dest(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); assert(s.next_bci() == limit_bci, "branch must end block"); state.apush(empty_map); successors.push(_methodBlocks->block_containing(dest_bci)); fall_through = false; break; } case Bytecodes::_ret: // we don't track the destination of a "ret" instruction assert(s.next_bci() == limit_bci, "branch must end block"); fall_through = false; break; case Bytecodes::_return: assert(s.next_bci() == limit_bci, "return must end block"); fall_through = false; break; case Bytecodes::_tableswitch: { state.spop(); Bytecode_tableswitch sw(&s); int len = sw.length(); int dest_bci; for (int i = 0; i < len; i++) { dest_bci = s.cur_bci() + sw.dest_offset_at(i); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); successors.push(_methodBlocks->block_containing(dest_bci)); } dest_bci = s.cur_bci() + sw.default_offset(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); successors.push(_methodBlocks->block_containing(dest_bci)); assert(s.next_bci() == limit_bci, "branch must end block"); fall_through = false; break; } case Bytecodes::_lookupswitch: { state.spop(); Bytecode_lookupswitch sw(&s); int len = sw.number_of_pairs(); int dest_bci; for (int i = 0; i < len; i++) { dest_bci = s.cur_bci() + sw.pair_at(i).offset(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); successors.push(_methodBlocks->block_containing(dest_bci)); } dest_bci = s.cur_bci() + sw.default_offset(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); successors.push(_methodBlocks->block_containing(dest_bci)); fall_through = false; break; } case Bytecodes::_ireturn: case Bytecodes::_freturn: state.spop(); fall_through = false; break; case Bytecodes::_lreturn: case Bytecodes::_dreturn: state.lpop(); fall_through = false; break; case Bytecodes::_areturn: set_returned(state.apop()); fall_through = false; break; case Bytecodes::_getstatic: case Bytecodes::_getfield: { bool ignored_will_link; ciField* field = s.get_field(ignored_will_link); BasicType field_type = field->type()->basic_type(); if (s.cur_bc() != Bytecodes::_getstatic) { set_method_escape(state.apop()); } if (field_type == T_OBJECT || field_type == T_ARRAY) { state.apush(unknown_obj); } else if (type2size[field_type] == 1) { state.spush(); } else { state.lpush(); } } break; case Bytecodes::_putstatic: case Bytecodes::_putfield: { bool will_link; ciField* field = s.get_field(will_link); BasicType field_type = field->type()->basic_type(); if (field_type == T_OBJECT || field_type == T_ARRAY) { set_global_escape(state.apop()); } else if (type2size[field_type] == 1) { state.spop(); } else { state.lpop(); } if (s.cur_bc() != Bytecodes::_putstatic) { ArgumentMap p = state.apop(); set_method_escape(p); set_modified(p, will_link ? field->offset() : OFFSET_ANY, type2size[field_type]*HeapWordSize); } } break; case Bytecodes::_invokevirtual: case Bytecodes::_invokespecial: case Bytecodes::_invokestatic: case Bytecodes::_invokedynamic: case Bytecodes::_invokeinterface: { bool ignored_will_link; ciSignature* declared_signature = NULL; ciMethod* target = s.get_method(ignored_will_link, &declared_signature); ciKlass* holder = s.get_declared_method_holder(); assert(declared_signature != NULL, "cannot be null"); // Push appendix argument, if one. if (s.has_appendix()) { state.apush(unknown_obj); } // Pass in raw bytecode because we need to see invokehandle instructions. invoke(state, s.cur_bc_raw(), target, holder); // We are using the return type of the declared signature here because // it might be a more concrete type than the one from the target (for // e.g. invokedynamic and invokehandle). ciType* return_type = declared_signature->return_type(); if (!return_type->is_primitive_type()) { state.apush(unknown_obj); } else if (return_type->is_one_word()) { state.spush(); } else if (return_type->is_two_word()) { state.lpush(); } } break; case Bytecodes::_new: state.apush(allocated_obj); break; case Bytecodes::_newarray: case Bytecodes::_anewarray: state.spop(); state.apush(allocated_obj); break; case Bytecodes::_multianewarray: { int i = s.cur_bcp()[3]; while (i-- > 0) state.spop(); state.apush(allocated_obj); } break; case Bytecodes::_arraylength: set_method_escape(state.apop()); state.spush(); break; case Bytecodes::_athrow: set_global_escape(state.apop()); fall_through = false; break; case Bytecodes::_checkcast: { ArgumentMap obj = state.apop(); set_method_escape(obj); state.apush(obj); } break; case Bytecodes::_instanceof: set_method_escape(state.apop()); state.spush(); break; case Bytecodes::_monitorenter: case Bytecodes::_monitorexit: state.apop(); break; case Bytecodes::_wide: ShouldNotReachHere(); break; case Bytecodes::_ifnull: case Bytecodes::_ifnonnull: { set_method_escape(state.apop()); int dest_bci = s.get_dest(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); assert(s.next_bci() == limit_bci, "branch must end block"); successors.push(_methodBlocks->block_containing(dest_bci)); break; } case Bytecodes::_goto_w: { int dest_bci = s.get_far_dest(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); assert(s.next_bci() == limit_bci, "branch must end block"); successors.push(_methodBlocks->block_containing(dest_bci)); fall_through = false; break; } case Bytecodes::_jsr_w: { int dest_bci = s.get_far_dest(); assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block"); assert(s.next_bci() == limit_bci, "branch must end block"); state.apush(empty_map); successors.push(_methodBlocks->block_containing(dest_bci)); fall_through = false; break; } case Bytecodes::_breakpoint: break; default: ShouldNotReachHere(); break; } } if (fall_through) { int fall_through_bci = s.cur_bci(); if (fall_through_bci < _method->code_size()) { assert(_methodBlocks->is_block_start(fall_through_bci), "must fall through to block start."); successors.push(_methodBlocks->block_containing(fall_through_bci)); } } } void BCEscapeAnalyzer::merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state) { StateInfo *d_state = blockstates + dest->index(); int nlocals = _method->max_locals(); // exceptions may cause transfer of control to handlers in the middle of a // block, so we don't merge the incoming state of exception handlers if (dest->is_handler()) return; if (!d_state->_initialized ) { // destination not initialized, just copy for (int i = 0; i < nlocals; i++) { d_state->_vars[i] = s_state->_vars[i]; } for (int i = 0; i < s_state->_stack_height; i++) { d_state->_stack[i] = s_state->_stack[i]; } d_state->_stack_height = s_state->_stack_height; d_state->_max_stack = s_state->_max_stack; d_state->_initialized = true; } else if (!dest->processed()) { // we have not yet walked the bytecodes of dest, we can merge // the states assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match"); for (int i = 0; i < nlocals; i++) { d_state->_vars[i].set_union(s_state->_vars[i]); } for (int i = 0; i < s_state->_stack_height; i++) { d_state->_stack[i].set_union(s_state->_stack[i]); } } else { // the bytecodes of dest have already been processed, mark any // arguments in the source state which are not in the dest state // as global escape. // Future refinement: we only need to mark these variable to the // maximum escape of any variables in dest state assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match"); ArgumentMap extra_vars; for (int i = 0; i < nlocals; i++) { ArgumentMap t; t = s_state->_vars[i]; t.set_difference(d_state->_vars[i]); extra_vars.set_union(t); } for (int i = 0; i < s_state->_stack_height; i++) { ArgumentMap t; //extra_vars |= !d_state->_vars[i] & s_state->_vars[i]; t.clear(); t = s_state->_stack[i]; t.set_difference(d_state->_stack[i]); extra_vars.set_union(t); } set_global_escape(extra_vars, true); } } void BCEscapeAnalyzer::iterate_blocks(Arena *arena) { int numblocks = _methodBlocks->num_blocks(); int stkSize = _method->max_stack(); int numLocals = _method->max_locals(); StateInfo state; int datacount = (numblocks + 1) * (stkSize + numLocals); int datasize = datacount * sizeof(ArgumentMap); StateInfo *blockstates = (StateInfo *) arena->Amalloc(numblocks * sizeof(StateInfo)); ArgumentMap *statedata = (ArgumentMap *) arena->Amalloc(datasize); for (int i = 0; i < datacount; i++) ::new ((void*)&statedata[i]) ArgumentMap(); ArgumentMap *dp = statedata; state._vars = dp; dp += numLocals; state._stack = dp; dp += stkSize; state._initialized = false; state._max_stack = stkSize; for (int i = 0; i < numblocks; i++) { blockstates[i]._vars = dp; dp += numLocals; blockstates[i]._stack = dp; dp += stkSize; blockstates[i]._initialized = false; blockstates[i]._stack_height = 0; blockstates[i]._max_stack = stkSize; } GrowableArray worklist(arena, numblocks / 4, 0, NULL); GrowableArray successors(arena, 4, 0, NULL); _methodBlocks->clear_processed(); // initialize block 0 state from method signature ArgumentMap allVars; // all oop arguments to method ciSignature* sig = method()->signature(); int j = 0; ciBlock* first_blk = _methodBlocks->block_containing(0); int fb_i = first_blk->index(); if (!method()->is_static()) { // record information for "this" blockstates[fb_i]._vars[j].set(j); allVars.add(j); j++; } for (int i = 0; i < sig->count(); i++) { ciType* t = sig->type_at(i); if (!t->is_primitive_type()) { blockstates[fb_i]._vars[j].set(j); allVars.add(j); } j += t->size(); } blockstates[fb_i]._initialized = true; assert(j == _arg_size, "just checking"); ArgumentMap unknown_map; unknown_map.add_unknown(); worklist.push(first_blk); while(worklist.length() > 0) { ciBlock *blk = worklist.pop(); StateInfo *blkState = blockstates + blk->index(); if (blk->is_handler() || blk->is_ret_target()) { // for an exception handler or a target of a ret instruction, we assume the worst case, // that any variable could contain any argument for (int i = 0; i < numLocals; i++) { state._vars[i] = allVars; } if (blk->is_handler()) { state._stack_height = 1; } else { state._stack_height = blkState->_stack_height; } for (int i = 0; i < state._stack_height; i++) { // ??? should this be unknown_map ??? state._stack[i] = allVars; } } else { for (int i = 0; i < numLocals; i++) { state._vars[i] = blkState->_vars[i]; } for (int i = 0; i < blkState->_stack_height; i++) { state._stack[i] = blkState->_stack[i]; } state._stack_height = blkState->_stack_height; } iterate_one_block(blk, state, successors); // if this block has any exception handlers, push them // onto successor list if (blk->has_handler()) { DEBUG_ONLY(int handler_count = 0;) int blk_start = blk->start_bci(); int blk_end = blk->limit_bci(); for (int i = 0; i < numblocks; i++) { ciBlock *b = _methodBlocks->block(i); if (b->is_handler()) { int ex_start = b->ex_start_bci(); int ex_end = b->ex_limit_bci(); if ((ex_start >= blk_start && ex_start < blk_end) || (ex_end > blk_start && ex_end <= blk_end)) { successors.push(b); } DEBUG_ONLY(handler_count++;) } } assert(handler_count > 0, "must find at least one handler"); } // merge computed variable state with successors while(successors.length() > 0) { ciBlock *succ = successors.pop(); merge_block_states(blockstates, succ, &state); if (!succ->processed()) worklist.push(succ); } } } bool BCEscapeAnalyzer::do_analysis() { Arena* arena = CURRENT_ENV->arena(); // identify basic blocks _methodBlocks = _method->get_method_blocks(); iterate_blocks(arena); // TEMPORARY return true; } vmIntrinsics::ID BCEscapeAnalyzer::known_intrinsic() { vmIntrinsics::ID iid = method()->intrinsic_id(); if (iid == vmIntrinsics::_getClass || iid == vmIntrinsics::_hashCode) return iid; else return vmIntrinsics::_none; } bool BCEscapeAnalyzer::compute_escape_for_intrinsic(vmIntrinsics::ID iid) { ArgumentMap arg; arg.clear(); switch (iid) { case vmIntrinsics::_getClass: _return_local = false; break; case vmIntrinsics::_hashCode: // initialized state is correct break; default: assert(false, "unexpected intrinsic"); } return true; } void BCEscapeAnalyzer::initialize() { int i; // clear escape information (method may have been deoptimized) methodData()->clear_escape_info(); // initialize escape state of object parameters ciSignature* sig = method()->signature(); int j = 0; if (!method()->is_static()) { _arg_local.set(0); _arg_stack.set(0); j++; } for (i = 0; i < sig->count(); i++) { ciType* t = sig->type_at(i); if (!t->is_primitive_type()) { _arg_local.set(j); _arg_stack.set(j); } j += t->size(); } assert(j == _arg_size, "just checking"); // start with optimistic assumption ciType *rt = _method->return_type(); if (rt->is_primitive_type()) { _return_local = false; _return_allocated = false; } else { _return_local = true; _return_allocated = true; } _allocated_escapes = false; _unknown_modified = false; } void BCEscapeAnalyzer::clear_escape_info() { ciSignature* sig = method()->signature(); int arg_count = sig->count(); ArgumentMap var; if (!method()->is_static()) { arg_count++; // allow for "this" } for (int i = 0; i < arg_count; i++) { set_arg_modified(i, OFFSET_ANY, 4); var.clear(); var.set(i); set_modified(var, OFFSET_ANY, 4); set_global_escape(var); } _arg_local.Clear(); _arg_stack.Clear(); _arg_returned.Clear(); _return_local = false; _return_allocated = false; _allocated_escapes = true; _unknown_modified = true; } void BCEscapeAnalyzer::compute_escape_info() { int i; assert(!methodData()->has_escape_info(), "do not overwrite escape info"); vmIntrinsics::ID iid = known_intrinsic(); // check if method can be analyzed if (iid == vmIntrinsics::_none && (method()->is_abstract() || method()->is_native() || !method()->holder()->is_initialized() || _level > MaxBCEAEstimateLevel || method()->code_size() > MaxBCEAEstimateSize)) { if (BCEATraceLevel >= 1) { tty->print("Skipping method because: "); if (method()->is_abstract()) tty->print_cr("method is abstract."); else if (method()->is_native()) tty->print_cr("method is native."); else if (!method()->holder()->is_initialized()) tty->print_cr("class of method is not initialized."); else if (_level > MaxBCEAEstimateLevel) tty->print_cr("level (%d) exceeds MaxBCEAEstimateLevel (%d).", _level, (int) MaxBCEAEstimateLevel); else if (method()->code_size() > MaxBCEAEstimateSize) tty->print_cr("code size (%d) exceeds MaxBCEAEstimateSize (%d).", method()->code_size(), (int) MaxBCEAEstimateSize); else ShouldNotReachHere(); } clear_escape_info(); return; } if (BCEATraceLevel >= 1) { tty->print("[EA] estimating escape information for"); if (iid != vmIntrinsics::_none) tty->print(" intrinsic"); method()->print_short_name(); tty->print_cr(" (%d bytes)", method()->code_size()); } bool success; initialize(); // Do not scan method if it has no object parameters and // does not returns an object (_return_allocated is set in initialize()). if (_arg_local.Size() == 0 && !_return_allocated) { // Clear all info since method's bytecode was not analysed and // set pessimistic escape information. clear_escape_info(); methodData()->set_eflag(MethodData::allocated_escapes); methodData()->set_eflag(MethodData::unknown_modified); methodData()->set_eflag(MethodData::estimated); return; } if (iid != vmIntrinsics::_none) success = compute_escape_for_intrinsic(iid); else { success = do_analysis(); } // don't store interprocedural escape information if it introduces // dependencies or if method data is empty // if (!has_dependencies() && !methodData()->is_empty()) { for (i = 0; i < _arg_size; i++) { if (_arg_local.test(i)) { assert(_arg_stack.test(i), "inconsistent escape info"); methodData()->set_arg_local(i); methodData()->set_arg_stack(i); } else if (_arg_stack.test(i)) { methodData()->set_arg_stack(i); } if (_arg_returned.test(i)) { methodData()->set_arg_returned(i); } methodData()->set_arg_modified(i, _arg_modified[i]); } if (_return_local) { methodData()->set_eflag(MethodData::return_local); } if (_return_allocated) { methodData()->set_eflag(MethodData::return_allocated); } if (_allocated_escapes) { methodData()->set_eflag(MethodData::allocated_escapes); } if (_unknown_modified) { methodData()->set_eflag(MethodData::unknown_modified); } methodData()->set_eflag(MethodData::estimated); } } void BCEscapeAnalyzer::read_escape_info() { assert(methodData()->has_escape_info(), "no escape info available"); // read escape information from method descriptor for (int i = 0; i < _arg_size; i++) { if (methodData()->is_arg_local(i)) _arg_local.set(i); if (methodData()->is_arg_stack(i)) _arg_stack.set(i); if (methodData()->is_arg_returned(i)) _arg_returned.set(i); _arg_modified[i] = methodData()->arg_modified(i); } _return_local = methodData()->eflag_set(MethodData::return_local); _return_allocated = methodData()->eflag_set(MethodData::return_allocated); _allocated_escapes = methodData()->eflag_set(MethodData::allocated_escapes); _unknown_modified = methodData()->eflag_set(MethodData::unknown_modified); } #ifndef PRODUCT void BCEscapeAnalyzer::dump() { tty->print("[EA] estimated escape information for"); method()->print_short_name(); tty->print_cr(has_dependencies() ? " (not stored)" : ""); tty->print(" non-escaping args: "); _arg_local.print(); tty->print(" stack-allocatable args: "); _arg_stack.print(); if (_return_local) { tty->print(" returned args: "); _arg_returned.print(); } else if (is_return_allocated()) { tty->print_cr(" return allocated value"); } else { tty->print_cr(" return non-local value"); } tty->print(" modified args: "); for (int i = 0; i < _arg_size; i++) { if (_arg_modified[i] == 0) tty->print(" 0"); else tty->print(" 0x%x", _arg_modified[i]); } tty->cr(); tty->print(" flags: "); if (_return_allocated) tty->print(" return_allocated"); if (_allocated_escapes) tty->print(" allocated_escapes"); if (_unknown_modified) tty->print(" unknown_modified"); tty->cr(); } #endif BCEscapeAnalyzer::BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent) : _conservative(method == NULL || !EstimateArgEscape) , _arena(CURRENT_ENV->arena()) , _method(method) , _methodData(method ? method->method_data() : NULL) , _arg_size(method ? method->arg_size() : 0) , _arg_local(_arena) , _arg_stack(_arena) , _arg_returned(_arena) , _dirty(_arena) , _return_local(false) , _return_allocated(false) , _allocated_escapes(false) , _unknown_modified(false) , _dependencies(_arena, 4, 0, NULL) , _parent(parent) , _level(parent == NULL ? 0 : parent->level() + 1) { if (!_conservative) { _arg_local.Clear(); _arg_stack.Clear(); _arg_returned.Clear(); _dirty.Clear(); Arena* arena = CURRENT_ENV->arena(); _arg_modified = (uint *) arena->Amalloc(_arg_size * sizeof(uint)); Copy::zero_to_bytes(_arg_modified, _arg_size * sizeof(uint)); if (methodData() == NULL) return; bool printit = _method->should_print_assembly(); if (methodData()->has_escape_info()) { TRACE_BCEA(2, tty->print_cr("[EA] Reading previous results for %s.%s", method->holder()->name()->as_utf8(), method->name()->as_utf8())); read_escape_info(); } else { TRACE_BCEA(2, tty->print_cr("[EA] computing results for %s.%s", method->holder()->name()->as_utf8(), method->name()->as_utf8())); compute_escape_info(); methodData()->update_escape_info(); } #ifndef PRODUCT if (BCEATraceLevel >= 3) { // dump escape information dump(); } #endif } } void BCEscapeAnalyzer::copy_dependencies(Dependencies *deps) { if (ciEnv::current()->jvmti_can_hotswap_or_post_breakpoint()) { // Also record evol dependencies so redefinition of the // callee will trigger recompilation. deps->assert_evol_method(method()); } for (int i = 0; i < _dependencies.length(); i+=2) { ciKlass *k = _dependencies.at(i)->as_klass(); ciMethod *m = _dependencies.at(i+1)->as_method(); deps->assert_unique_concrete_method(k, m); } }