truffle: src/share/vm/c1/c1

comparison src/share/vm/c1/c1_IR.cpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	334969144810

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--1:000000000000
+:a61af66fc99e
+/*
+* Copyright 1999-2006 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/_c1_IR.cpp.incl"
+// Implementation of XHandlers
+//
+// Note: This code could eventually go away if we are
+//       just using the ciExceptionHandlerStream.
+XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) {
+ciExceptionHandlerStream s(method);
+while (!s.is_done()) {
+_list.append(new XHandler(s.handler()));
+s.next();
+}
+assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent");
+}
+// deep copy of all XHandler contained in list
+XHandlers::XHandlers(XHandlers* other) :
+_list(other->length())
+{
+for (int i = 0; i < other->length(); i++) {
+_list.append(new XHandler(other->handler_at(i)));
+}
+}
+// Returns whether a particular exception type can be caught.  Also
+// returns true if klass is unloaded or any exception handler
+// classes are unloaded.  type_is_exact indicates whether the throw
+// is known to be exactly that class or it might throw a subtype.
+bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const {
+// the type is unknown so be conservative
+if (!klass->is_loaded()) {
+return true;
+}
+for (int i = 0; i < length(); i++) {
+XHandler* handler = handler_at(i);
+if (handler->is_catch_all()) {
+// catch of ANY
+return true;
+}
+ciInstanceKlass* handler_klass = handler->catch_klass();
+// if it's unknown it might be catchable
+if (!handler_klass->is_loaded()) {
+return true;
+}
+// if the throw type is definitely a subtype of the catch type
+// then it can be caught.
+if (klass->is_subtype_of(handler_klass)) {
+return true;
+}
+if (!type_is_exact) {
+// If the type isn't exactly known then it can also be caught by
+// catch statements where the inexact type is a subtype of the
+// catch type.
+// given: foo extends bar extends Exception
+// throw bar can be caught by catch foo, catch bar, and catch
+// Exception, however it can't be caught by any handlers without
+// bar in its type hierarchy.
+if (handler_klass->is_subtype_of(klass)) {
+return true;
+}
+}
+}
+return false;
+}
+bool XHandlers::equals(XHandlers* others) const {
+if (others == NULL) return false;
+if (length() != others->length()) return false;
+for (int i = 0; i < length(); i++) {
+if (!handler_at(i)->equals(others->handler_at(i))) return false;
+}
+return true;
+}
+bool XHandler::equals(XHandler* other) const {
+assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco");
+if (entry_pco() != other->entry_pco()) return false;
+if (scope_count() != other->scope_count()) return false;
+if (_desc != other->_desc) return false;
+assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal");
+return true;
+}
+// Implementation of IRScope
+BlockBegin* IRScope::header_block(BlockBegin* entry, BlockBegin::Flag f, ValueStack* state) {
+if (entry == NULL) return NULL;
+assert(entry->is_set(f), "entry/flag mismatch");
+// create header block
+BlockBegin* h = new BlockBegin(entry->bci());
+BlockEnd* g = new Goto(entry, false);
+h->set_next(g, entry->bci());
+h->set_end(g);
+h->set(f);
+// setup header block end state
+ValueStack* s = state->copy(); // can use copy since stack is empty (=> no phis)
+assert(s->stack_is_empty(), "must have empty stack at entry point");
+g->set_state(s);
+return h;
+}
+BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) {
+GraphBuilder gm(compilation, this);
+NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats());
+if (compilation->bailed_out()) return NULL;
+return gm.start();
+}
+IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph)
+: _callees(2)
+, _compilation(compilation)
+, _lock_stack_size(-1)
+, _requires_phi_function(method->max_locals())
+{
+_caller             = caller;
+_caller_bci         = caller == NULL ? -1 : caller_bci;
+_caller_state       = NULL; // Must be set later if needed
+_level              = caller == NULL ?  0 : caller->level() + 1;
+_method             = method;
+_xhandlers          = new XHandlers(method);
+_number_of_locks    = 0;
+_monitor_pairing_ok = method->has_balanced_monitors();
+_start              = NULL;
+if (osr_bci == -1) {
+_requires_phi_function.clear();
+} else {
+// selective creation of phi functions is not possibel in osr-methods
+_requires_phi_function.set_range(0, method->max_locals());
+}
+assert(method->holder()->is_loaded() , "method holder must be loaded");
+// build graph if monitor pairing is ok
+if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci);
+}
+int IRScope::max_stack() const {
+int my_max = method()->max_stack();
+int callee_max = 0;
+for (int i = 0; i < number_of_callees(); i++) {
+callee_max = MAX2(callee_max, callee_no(i)->max_stack());
+}
+return my_max + callee_max;
+}
+void IRScope::compute_lock_stack_size() {
+if (!InlineMethodsWithExceptionHandlers) {
+_lock_stack_size = 0;
+return;
+}
+// Figure out whether we have to preserve expression stack elements
+// for parent scopes, and if so, how many
+IRScope* cur_scope = this;
+while (cur_scope != NULL && !cur_scope->xhandlers()->has_handlers()) {
+cur_scope = cur_scope->caller();
+}
+_lock_stack_size = (cur_scope == NULL ? 0 :
+(cur_scope->caller_state() == NULL ? 0 :
+cur_scope->caller_state()->stack_size()));
+}
+int IRScope::top_scope_bci() const {
+assert(!is_top_scope(), "no correct answer for top scope possible");
+const IRScope* scope = this;
+while (!scope->caller()->is_top_scope()) {
+scope = scope->caller();
+}
+return scope->caller_bci();
+}
+// Implementation of CodeEmitInfo
+// Stack must be NON-null
+CodeEmitInfo::CodeEmitInfo(int bci, ValueStack* stack, XHandlers* exception_handlers)
+: _scope(stack->scope())
+, _bci(bci)
+, _scope_debug_info(NULL)
+, _oop_map(NULL)
+, _stack(stack)
+, _exception_handlers(exception_handlers)
+, _next(NULL)
+, _id(-1) {
+assert(_stack != NULL, "must be non null");
+assert(_bci == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(_bci)), "make sure bci points at a real bytecode");
+}
+CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, bool lock_stack_only)
+: _scope(info->_scope)
+, _exception_handlers(NULL)
+, _bci(info->_bci)
+, _scope_debug_info(NULL)
+, _oop_map(NULL) {
+if (lock_stack_only) {
+if (info->_stack != NULL) {
+_stack = info->_stack->copy_locks();
+} else {
+_stack = NULL;
+}
+} else {
+_stack = info->_stack;
+}
+// deep copy of exception handlers
+if (info->_exception_handlers != NULL) {
+_exception_handlers = new XHandlers(info->_exception_handlers);
+}
+}
+void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) {
+// record the safepoint before recording the debug info for enclosing scopes
+recorder->add_safepoint(pc_offset, _oop_map->deep_copy());
+_scope_debug_info->record_debug_info(recorder, pc_offset);
+recorder->end_safepoint(pc_offset);
+}
+void CodeEmitInfo::add_register_oop(LIR_Opr opr) {
+assert(_oop_map != NULL, "oop map must already exist");
+assert(opr->is_single_cpu(), "should not call otherwise");
+int frame_size = frame_map()->framesize();
+int arg_count = frame_map()->oop_map_arg_count();
+VMReg name = frame_map()->regname(opr);
+_oop_map->set_oop(name);
+}
+// Implementation of IR
+IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) :
+_locals_size(in_WordSize(-1))
+, _num_loops(0) {
+// initialize data structures
+ValueType::initialize();
+Instruction::initialize();
+BlockBegin::initialize();
+GraphBuilder::initialize();
+// setup IR fields
+_compilation = compilation;
+_top_scope   = new IRScope(compilation, NULL, -1, method, osr_bci, true);
+_code        = NULL;
+}
+void IR::optimize() {
+Optimizer opt(this);
+if (DoCEE) {
+opt.eliminate_conditional_expressions();
+#ifndef PRODUCT
+if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); }
+if (PrintIR  || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); }
+#endif
+}
+if (EliminateBlocks) {
+opt.eliminate_blocks();
+#ifndef PRODUCT
+if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); }
+if (PrintIR  || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); }
+#endif
+}
+if (EliminateNullChecks) {
+opt.eliminate_null_checks();
+#ifndef PRODUCT
+if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); }
+if (PrintIR  || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); }
+#endif
+}
+}
+static int sort_pairs(BlockPair** a, BlockPair** b) {
+if ((*a)->from() == (*b)->from()) {
+return (*a)->to()->block_id() - (*b)->to()->block_id();
+} else {
+return (*a)->from()->block_id() - (*b)->from()->block_id();
+}
+}
+class CriticalEdgeFinder: public BlockClosure {
+BlockPairList blocks;
+IR*       _ir;
+public:
+CriticalEdgeFinder(IR* ir): _ir(ir) {}
+void block_do(BlockBegin* bb) {
+BlockEnd* be = bb->end();
+int nos = be->number_of_sux();
+if (nos >= 2) {
+for (int i = 0; i < nos; i++) {
+BlockBegin* sux = be->sux_at(i);
+if (sux->number_of_preds() >= 2) {
+blocks.append(new BlockPair(bb, sux));
+}
+}
+}
+}
+void split_edges() {
+BlockPair* last_pair = NULL;
+blocks.sort(sort_pairs);
+for (int i = 0; i < blocks.length(); i++) {
+BlockPair* pair = blocks.at(i);
+if (last_pair != NULL && pair->is_same(last_pair)) continue;
+BlockBegin* from = pair->from();
+BlockBegin* to = pair->to();
+BlockBegin* split = from->insert_block_between(to);
+#ifndef PRODUCT
+if ((PrintIR || PrintIR1) && Verbose) {
+tty->print_cr("Split critical edge B%d -> B%d (new block B%d)",
+from->block_id(), to->block_id(), split->block_id());
+}
+#endif
+last_pair = pair;
+}
+}
+};
+void IR::split_critical_edges() {
+CriticalEdgeFinder cef(this);
+iterate_preorder(&cef);
+cef.split_edges();
+}
+class UseCountComputer: public AllStatic {
+private:
+static void update_use_count(Value* n) {
+// Local instructions and Phis for expression stack values at the
+// start of basic blocks are not added to the instruction list
+if ((*n)->bci() == -99 && (*n)->as_Local() == NULL &&
+(*n)->as_Phi() == NULL) {
+assert(false, "a node was not appended to the graph");
+Compilation::current_compilation()->bailout("a node was not appended to the graph");
+}
+// use n's input if not visited before
+if (!(*n)->is_pinned() && !(*n)->has_uses()) {
+// note: a) if the instruction is pinned, it will be handled by compute_use_count
+//       b) if the instruction has uses, it was touched before
+//       => in both cases we don't need to update n's values
+uses_do(n);
+}
+// use n
+(*n)->_use_count++;
+}
+static Values* worklist;
+static int depth;
+enum {
+max_recurse_depth = 20
+};
+static void uses_do(Value* n) {
+depth++;
+if (depth > max_recurse_depth) {
+// don't allow the traversal to recurse too deeply
+worklist->push(*n);
+} else {
+(*n)->input_values_do(update_use_count);
+// special handling for some instructions
+if ((*n)->as_BlockEnd() != NULL) {
+// note on BlockEnd:
+//   must 'use' the stack only if the method doesn't
+//   terminate, however, in those cases stack is empty
+(*n)->state_values_do(update_use_count);
+}
+}
+depth--;
+}
+static void basic_compute_use_count(BlockBegin* b) {
+depth = 0;
+// process all pinned nodes as the roots of expression trees
+for (Instruction* n = b; n != NULL; n = n->next()) {
+if (n->is_pinned()) uses_do(&n);
+}
+assert(depth == 0, "should have counted back down");
+// now process any unpinned nodes which recursed too deeply
+while (worklist->length() > 0) {
+Value t = worklist->pop();
+if (!t->is_pinned()) {
+// compute the use count
+uses_do(&t);
+// pin the instruction so that LIRGenerator doesn't recurse
+// too deeply during it's evaluation.
+t->pin();
+}
+}
+assert(depth == 0, "should have counted back down");
+}
+public:
+static void compute(BlockList* blocks) {
+worklist = new Values();
+blocks->blocks_do(basic_compute_use_count);
+worklist = NULL;
+}
+};
+Values* UseCountComputer::worklist = NULL;
+int UseCountComputer::depth = 0;
+// helper macro for short definition of trace-output inside code
+#ifndef PRODUCT
+#define TRACE_LINEAR_SCAN(level, code)       \
+if (TraceLinearScanLevel >= level) {       \
+code;                                    \
+}
+#else
+#define TRACE_LINEAR_SCAN(level, code)
+#endif
+class ComputeLinearScanOrder : public StackObj {
+private:
+int        _max_block_id;        // the highest block_id of a block
+int        _num_blocks;          // total number of blocks (smaller than _max_block_id)
+int        _num_loops;           // total number of loops
+bool       _iterative_dominators;// method requires iterative computation of dominatiors
+BlockList* _linear_scan_order;   // the resulting list of blocks in correct order
+BitMap     _visited_blocks;      // used for recursive processing of blocks
+BitMap     _active_blocks;       // used for recursive processing of blocks
+BitMap     _dominator_blocks;    // temproary BitMap used for computation of dominator
+intArray   _forward_branches;    // number of incoming forward branches for each block
+BlockList  _loop_end_blocks;     // list of all loop end blocks collected during count_edges
+BitMap2D   _loop_map;            // two-dimensional bit set: a bit is set if a block is contained in a loop
+BlockList  _work_list;           // temporary list (used in mark_loops and compute_order)
+// accessors for _visited_blocks and _active_blocks
+void init_visited()                     { _active_blocks.clear(); _visited_blocks.clear(); }
+bool is_visited(BlockBegin* b) const    { return _visited_blocks.at(b->block_id()); }
+bool is_active(BlockBegin* b) const     { return _active_blocks.at(b->block_id()); }
+void set_visited(BlockBegin* b)         { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); }
+void set_active(BlockBegin* b)          { assert(!is_active(b), "already set");  _active_blocks.set_bit(b->block_id()); }
+void clear_active(BlockBegin* b)        { assert(is_active(b), "not already");   _active_blocks.clear_bit(b->block_id()); }
+// accessors for _forward_branches
+void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); }
+int  dec_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) - 1); return _forward_branches.at(b->block_id()); }
+// accessors for _loop_map
+bool is_block_in_loop   (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); }
+void set_block_in_loop  (int loop_idx, BlockBegin* b)       { _loop_map.set_bit(loop_idx, b->block_id()); }
+void clear_block_in_loop(int loop_idx, int block_id)        { _loop_map.clear_bit(loop_idx, block_id); }
+// count edges between blocks
+void count_edges(BlockBegin* cur, BlockBegin* parent);
+// loop detection
+void mark_loops();
+void clear_non_natural_loops(BlockBegin* start_block);
+void assign_loop_depth(BlockBegin* start_block);
+// computation of final block order
+BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b);
+void compute_dominator(BlockBegin* cur, BlockBegin* parent);
+int  compute_weight(BlockBegin* cur);
+bool ready_for_processing(BlockBegin* cur);
+void sort_into_work_list(BlockBegin* b);
+void append_block(BlockBegin* cur);
+void compute_order(BlockBegin* start_block);
+// fixup of dominators for non-natural loops
+bool compute_dominators_iter();
+void compute_dominators();
+// debug functions
+NOT_PRODUCT(void print_blocks();)
+DEBUG_ONLY(void verify();)
+public:
+ComputeLinearScanOrder(BlockBegin* start_block);
+// accessors for final result
+BlockList* linear_scan_order() const    { return _linear_scan_order; }
+int        num_loops() const            { return _num_loops; }
+};
+ComputeLinearScanOrder::ComputeLinearScanOrder(BlockBegin* start_block) :
+_max_block_id(BlockBegin::number_of_blocks()),
+_num_blocks(0),
+_num_loops(0),
+_iterative_dominators(false),
+_visited_blocks(_max_block_id),
+_active_blocks(_max_block_id),
+_dominator_blocks(_max_block_id),
+_forward_branches(_max_block_id, 0),
+_loop_end_blocks(8),
+_work_list(8),
+_linear_scan_order(NULL), // initialized later with correct size
+_loop_map(0, 0)           // initialized later with correct size
+{
+TRACE_LINEAR_SCAN(2, "***** computing linear-scan block order");
+init_visited();
+count_edges(start_block, NULL);
+if (_num_loops > 0) {
+mark_loops();
+clear_non_natural_loops(start_block);
+assign_loop_depth(start_block);
+}
+compute_order(start_block);
+compute_dominators();
+NOT_PRODUCT(print_blocks());
+DEBUG_ONLY(verify());
+}
+// Traverse the CFG:
+// * count total number of blocks
+// * count all incoming edges and backward incoming edges
+// * number loop header blocks
+// * create a list with all loop end blocks
+void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("Enter count_edges for block B%d coming from B%d", cur->block_id(), parent != NULL ? parent->block_id() : -1));
+assert(cur->dominator() == NULL, "dominator already initialized");
+if (is_active(cur)) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch"));
+assert(is_visited(cur), "block must be visisted when block is active");
+assert(parent != NULL, "must have parent");
+assert(parent->number_of_sux() == 1, "loop end blocks must have one successor (critical edges are split)");
+cur->set(BlockBegin::linear_scan_loop_header_flag);
+cur->set(BlockBegin::backward_branch_target_flag);
+parent->set(BlockBegin::linear_scan_loop_end_flag);
+_loop_end_blocks.append(parent);
+return;
+}
+// increment number of incoming forward branches
+inc_forward_branches(cur);
+if (is_visited(cur)) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited"));
+return;
+}
+_num_blocks++;
+set_visited(cur);
+set_active(cur);
+// recursive call for all successors
+int i;
+for (i = cur->number_of_sux() - 1; i >= 0; i--) {
+count_edges(cur->sux_at(i), cur);
+}
+for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) {
+count_edges(cur->exception_handler_at(i), cur);
+}
+clear_active(cur);
+// Each loop has a unique number.
+// When multiple loops are nested, assign_loop_depth assumes that the
+// innermost loop has the lowest number. This is guaranteed by setting
+// the loop number after the recursive calls for the successors above
+// have returned.
+if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) {
+assert(cur->loop_index() == -1, "cannot set loop-index twice");
+TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops));
+cur->set_loop_index(_num_loops);
+_num_loops++;
+}
+TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id()));
+}
+void ComputeLinearScanOrder::mark_loops() {
+TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops"));
+_loop_map = BitMap2D(_num_loops, _max_block_id);
+_loop_map.clear();
+for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) {
+BlockBegin* loop_end   = _loop_end_blocks.at(i);
+BlockBegin* loop_start = loop_end->sux_at(0);
+int         loop_idx   = loop_start->loop_index();
+TRACE_LINEAR_SCAN(3, tty->print_cr("Processing loop from B%d to B%d (loop %d):", loop_start->block_id(), loop_end->block_id(), loop_idx));
+assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set");
+assert(loop_end->number_of_sux() == 1, "incorrect number of successors");
+assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set");
+assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set");
+assert(_work_list.is_empty(), "work list must be empty before processing");
+// add the end-block of the loop to the working list
+_work_list.push(loop_end);
+set_block_in_loop(loop_idx, loop_end);
+do {
+BlockBegin* cur = _work_list.pop();
+TRACE_LINEAR_SCAN(3, tty->print_cr("    processing B%d", cur->block_id()));
+assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list");
+// recursive processing of all predecessors ends when start block of loop is reached
+if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) {
+for (int j = cur->number_of_preds() - 1; j >= 0; j--) {
+BlockBegin* pred = cur->pred_at(j);
+if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) {
+// this predecessor has not been processed yet, so add it to work list
+TRACE_LINEAR_SCAN(3, tty->print_cr("    pushing B%d", pred->block_id()));
+_work_list.push(pred);
+set_block_in_loop(loop_idx, pred);
+}
+}
+}
+} while (!_work_list.is_empty());
+}
+}
+// check for non-natural loops (loops where the loop header does not dominate
+// all other loop blocks = loops with mulitple entries).
+// such loops are ignored
+void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) {
+for (int i = _num_loops - 1; i >= 0; i--) {
+if (is_block_in_loop(i, start_block)) {
+// loop i contains the entry block of the method
+// -> this is not a natural loop, so ignore it
+TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i));
+for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) {
+clear_block_in_loop(i, block_id);
+}
+_iterative_dominators = true;
+}
+}
+}
+void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) {
+TRACE_LINEAR_SCAN(3, "----- computing loop-depth and weight");
+init_visited();
+assert(_work_list.is_empty(), "work list must be empty before processing");
+_work_list.append(start_block);
+do {
+BlockBegin* cur = _work_list.pop();
+if (!is_visited(cur)) {
+set_visited(cur);
+TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id()));
+// compute loop-depth and loop-index for the block
+assert(cur->loop_depth() == 0, "cannot set loop-depth twice");
+int i;
+int loop_depth = 0;
+int min_loop_idx = -1;
+for (i = _num_loops - 1; i >= 0; i--) {
+if (is_block_in_loop(i, cur)) {
+loop_depth++;
+min_loop_idx = i;
+}
+}
+cur->set_loop_depth(loop_depth);
+cur->set_loop_index(min_loop_idx);
+// append all unvisited successors to work list
+for (i = cur->number_of_sux() - 1; i >= 0; i--) {
+_work_list.append(cur->sux_at(i));
+}
+for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) {
+_work_list.append(cur->exception_handler_at(i));
+}
+}
+} while (!_work_list.is_empty());
+}
+BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) {
+assert(a != NULL && b != NULL, "must have input blocks");
+_dominator_blocks.clear();
+while (a != NULL) {
+_dominator_blocks.set_bit(a->block_id());
+assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized");
+a = a->dominator();
+}
+while (b != NULL && !_dominator_blocks.at(b->block_id())) {
+assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized");
+b = b->dominator();
+}
+assert(b != NULL, "could not find dominator");
+return b;
+}
+void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) {
+if (cur->dominator() == NULL) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id()));
+cur->set_dominator(parent);
+} else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: computing dominator of B%d: common dominator of B%d and B%d is B%d", cur->block_id(), parent->block_id(), cur->dominator()->block_id(), common_dominator(cur->dominator(), parent)->block_id()));
+assert(cur->number_of_preds() > 1, "");
+cur->set_dominator(common_dominator(cur->dominator(), parent));
+}
+}
+int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) {
+BlockBegin* single_sux = NULL;
+if (cur->number_of_sux() == 1) {
+single_sux = cur->sux_at(0);
+}
+// limit loop-depth to 15 bit (only for security reason, it will never be so big)
+int weight = (cur->loop_depth() & 0x7FFF) << 16;
+// general macro for short definition of weight flags
+// the first instance of INC_WEIGHT_IF has the highest priority
+int cur_bit = 15;
+#define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--;
+// this is necessery for the (very rare) case that two successing blocks have
+// the same loop depth, but a different loop index (can happen for endless loops
+// with exception handlers)
+INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag));
+// loop end blocks (blocks that end with a backward branch) are added
+// after all other blocks of the loop.
+INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag));
+// critical edge split blocks are prefered because than they have a bigger
+// proability to be completely empty
+INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag));
+// exceptions should not be thrown in normal control flow, so these blocks
+// are added as late as possible
+INC_WEIGHT_IF(cur->end()->as_Throw() == NULL  && (single_sux == NULL || single_sux->end()->as_Throw()  == NULL));
+INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL));
+// exceptions handlers are added as late as possible
+INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag));
+// guarantee that weight is > 0
+weight |= 1;
+#undef INC_WEIGHT_IF
+assert(cur_bit >= 0, "too many flags");
+assert(weight > 0, "weight cannot become negative");
+return weight;
+}
+bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) {
+// Discount the edge just traveled.
+// When the number drops to zero, all forward branches were processed
+if (dec_forward_branches(cur) != 0) {
+return false;
+}
+assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)");
+assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)");
+return true;
+}
+void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) {
+assert(_work_list.index_of(cur) == -1, "block already in work list");
+int cur_weight = compute_weight(cur);
+// the linear_scan_number is used to cache the weight of a block
+cur->set_linear_scan_number(cur_weight);
+#ifndef PRODUCT
+if (StressLinearScan) {
+_work_list.insert_before(0, cur);
+return;
+}
+#endif
+_work_list.append(NULL); // provide space for new element
+int insert_idx = _work_list.length() - 1;
+while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) {
+_work_list.at_put(insert_idx, _work_list.at(insert_idx - 1));
+insert_idx--;
+}
+_work_list.at_put(insert_idx, cur);
+TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id()));
+TRACE_LINEAR_SCAN(3, for (int i = 0; i < _work_list.length(); i++) tty->print_cr("%8d B%2d  weight:%6x", i, _work_list.at(i)->block_id(), _work_list.at(i)->linear_scan_number()));
+#ifdef ASSERT
+for (int i = 0; i < _work_list.length(); i++) {
+assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set");
+assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist");
+}
+#endif
+}
+void ComputeLinearScanOrder::append_block(BlockBegin* cur) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("appending block B%d (weight 0x%6x) to linear-scan order", cur->block_id(), cur->linear_scan_number()));
+assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice");
+// currently, the linear scan order and code emit order are equal.
+// therefore the linear_scan_number and the weight of a block must also
+// be equal.
+cur->set_linear_scan_number(_linear_scan_order->length());
+_linear_scan_order->append(cur);
+}
+void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) {
+TRACE_LINEAR_SCAN(3, "----- computing final block order");
+// the start block is always the first block in the linear scan order
+_linear_scan_order = new BlockList(_num_blocks);
+append_block(start_block);
+assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction");
+BlockBegin* std_entry = ((Base*)start_block->end())->std_entry();
+BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry();
+BlockBegin* sux_of_osr_entry = NULL;
+if (osr_entry != NULL) {
+// special handling for osr entry:
+// ignore the edge between the osr entry and its successor for processing
+// the osr entry block is added manually below
+assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor");
+assert(osr_entry->sux_at(0)->number_of_preds() >= 2, "sucessor of osr entry must have two predecessors (otherwise it is not present in normal control flow");
+sux_of_osr_entry = osr_entry->sux_at(0);
+dec_forward_branches(sux_of_osr_entry);
+compute_dominator(osr_entry, start_block);
+_iterative_dominators = true;
+}
+compute_dominator(std_entry, start_block);
+// start processing with standard entry block
+assert(_work_list.is_empty(), "list must be empty before processing");
+if (ready_for_processing(std_entry)) {
+sort_into_work_list(std_entry);
+} else {
+assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)");
+}
+do {
+BlockBegin* cur = _work_list.pop();
+if (cur == sux_of_osr_entry) {
+// the osr entry block is ignored in normal processing, it is never added to the
+// work list. Instead, it is added as late as possible manually here.
+append_block(osr_entry);
+compute_dominator(cur, osr_entry);
+}
+append_block(cur);
+int i;
+int num_sux = cur->number_of_sux();
+// changed loop order to get "intuitive" order of if- and else-blocks
+for (i = 0; i < num_sux; i++) {
+BlockBegin* sux = cur->sux_at(i);
+compute_dominator(sux, cur);
+if (ready_for_processing(sux)) {
+sort_into_work_list(sux);
+}
+}
+num_sux = cur->number_of_exception_handlers();
+for (i = 0; i < num_sux; i++) {
+BlockBegin* sux = cur->exception_handler_at(i);
+compute_dominator(sux, cur);
+if (ready_for_processing(sux)) {
+sort_into_work_list(sux);
+}
+}
+} while (_work_list.length() > 0);
+}
+bool ComputeLinearScanOrder::compute_dominators_iter() {
+bool changed = false;
+int num_blocks = _linear_scan_order->length();
+assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator");
+assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors");
+for (int i = 1; i < num_blocks; i++) {
+BlockBegin* block = _linear_scan_order->at(i);
+BlockBegin* dominator = block->pred_at(0);
+int num_preds = block->number_of_preds();
+for (int i = 1; i < num_preds; i++) {
+dominator = common_dominator(dominator, block->pred_at(i));
+}
+if (dominator != block->dominator()) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: updating dominator of B%d from B%d to B%d", block->block_id(), block->dominator()->block_id(), dominator->block_id()));
+block->set_dominator(dominator);
+changed = true;
+}
+}
+return changed;
+}
+void ComputeLinearScanOrder::compute_dominators() {
+TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators));
+// iterative computation of dominators is only required for methods with non-natural loops
+// and OSR-methods. For all other methods, the dominators computed when generating the
+// linear scan block order are correct.
+if (_iterative_dominators) {
+do {
+TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation"));
+} while (compute_dominators_iter());
+}
+// check that dominators are correct
+assert(!compute_dominators_iter(), "fix point not reached");
+}
+#ifndef PRODUCT
+void ComputeLinearScanOrder::print_blocks() {
+if (TraceLinearScanLevel >= 2) {
+tty->print_cr("----- loop information:");
+for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) {
+BlockBegin* cur = _linear_scan_order->at(block_idx);
+tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id());
+for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) {
+tty->print ("%d ", is_block_in_loop(loop_idx, cur));
+}
+tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth());
+}
+}
+if (TraceLinearScanLevel >= 1) {
+tty->print_cr("----- linear-scan block order:");
+for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) {
+BlockBegin* cur = _linear_scan_order->at(block_idx);
+tty->print("%4d: B%2d    loop: %2d  depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth());
+tty->print(cur->is_set(BlockBegin::exception_entry_flag)         ? " ex" : "   ");
+tty->print(cur->is_set(BlockBegin::critical_edge_split_flag)     ? " ce" : "   ");
+tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : "   ");
+tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag)    ? " le" : "   ");
+if (cur->dominator() != NULL) {
+tty->print("    dom: B%d ", cur->dominator()->block_id());
+} else {
+tty->print("    dom: NULL ");
+}
+if (cur->number_of_preds() > 0) {
+tty->print("    preds: ");
+for (int j = 0; j < cur->number_of_preds(); j++) {
+BlockBegin* pred = cur->pred_at(j);
+tty->print("B%d ", pred->block_id());
+}
+}
+if (cur->number_of_sux() > 0) {
+tty->print("    sux: ");
+for (int j = 0; j < cur->number_of_sux(); j++) {
+BlockBegin* sux = cur->sux_at(j);
+tty->print("B%d ", sux->block_id());
+}
+}
+if (cur->number_of_exception_handlers() > 0) {
+tty->print("    ex: ");
+for (int j = 0; j < cur->number_of_exception_handlers(); j++) {
+BlockBegin* ex = cur->exception_handler_at(j);
+tty->print("B%d ", ex->block_id());
+}
+}
+tty->cr();
+}
+}
+}
+#endif
+#ifdef ASSERT
+void ComputeLinearScanOrder::verify() {
+assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list");
+if (StressLinearScan) {
+// blocks are scrambled when StressLinearScan is used
+return;
+}
+// check that all successors of a block have a higher linear-scan-number
+// and that all predecessors of a block have a lower linear-scan-number
+// (only backward branches of loops are ignored)
+int i;
+for (i = 0; i < _linear_scan_order->length(); i++) {
+BlockBegin* cur = _linear_scan_order->at(i);
+assert(cur->linear_scan_number() == i, "incorrect linear_scan_number");
+assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number");
+int j;
+for (j = cur->number_of_sux() - 1; j >= 0; j--) {
+BlockBegin* sux = cur->sux_at(j);
+assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number");
+if (!cur->is_set(BlockBegin::linear_scan_loop_end_flag)) {
+assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order");
+}
+if (cur->loop_depth() == sux->loop_depth()) {
+assert(cur->loop_index() == sux->loop_index() || sux->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index");
+}
+}
+for (j = cur->number_of_preds() - 1; j >= 0; j--) {
+BlockBegin* pred = cur->pred_at(j);
+assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number");
+if (!cur->is_set(BlockBegin::linear_scan_loop_header_flag)) {
+assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order");
+}
+if (cur->loop_depth() == pred->loop_depth()) {
+assert(cur->loop_index() == pred->loop_index() || cur->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index");
+}
+assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors");
+}
+// check dominator
+if (i == 0) {
+assert(cur->dominator() == NULL, "first block has no dominator");
+} else {
+assert(cur->dominator() != NULL, "all but first block must have dominator");
+}
+assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0), "Single predecessor must also be dominator");
+}
+// check that all loops are continuous
+for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) {
+int block_idx = 0;
+assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop");
+// skip blocks before the loop
+while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) {
+block_idx++;
+}
+// skip blocks of loop
+while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) {
+block_idx++;
+}
+// after the first non-loop block, there must not be another loop-block
+while (block_idx < _num_blocks) {
+assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order");
+block_idx++;
+}
+}
+}
+#endif
+void IR::compute_code() {
+assert(is_valid(), "IR must be valid");
+ComputeLinearScanOrder compute_order(start());
+_num_loops = compute_order.num_loops();
+_code = compute_order.linear_scan_order();
+}
+void IR::compute_use_counts() {
+// make sure all values coming out of this block get evaluated.
+int num_blocks = _code->length();
+for (int i = 0; i < num_blocks; i++) {
+_code->at(i)->end()->state()->pin_stack_for_linear_scan();
+}
+// compute use counts
+UseCountComputer::compute(_code);
+}
+void IR::iterate_preorder(BlockClosure* closure) {
+assert(is_valid(), "IR must be valid");
+start()->iterate_preorder(closure);
+}
+void IR::iterate_postorder(BlockClosure* closure) {
+assert(is_valid(), "IR must be valid");
+start()->iterate_postorder(closure);
+}
+void IR::iterate_linear_scan_order(BlockClosure* closure) {
+linear_scan_order()->iterate_forward(closure);
+}
+#ifndef PRODUCT
+class BlockPrinter: public BlockClosure {
+private:
+InstructionPrinter* _ip;
+bool                _cfg_only;
+bool                _live_only;
+public:
+BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) {
+_ip       = ip;
+_cfg_only = cfg_only;
+_live_only = live_only;
+}
+virtual void block_do(BlockBegin* block) {
+if (_cfg_only) {
+_ip->print_instr(block); tty->cr();
+} else {
+block->print_block(*_ip, _live_only);
+}
+}
+};
+void IR::print(BlockBegin* start, bool cfg_only, bool live_only) {
+ttyLocker ttyl;
+InstructionPrinter ip(!cfg_only);
+BlockPrinter bp(&ip, cfg_only, live_only);
+start->iterate_preorder(&bp);
+tty->cr();
+}
+void IR::print(bool cfg_only, bool live_only) {
+if (is_valid()) {
+print(start(), cfg_only, live_only);
+} else {
+tty->print_cr("invalid IR");
+}
+}
+define_array(BlockListArray, BlockList*)
+define_stack(BlockListList, BlockListArray)
+class PredecessorValidator : public BlockClosure {
+private:
+BlockListList* _predecessors;
+BlockList*     _blocks;
+static int cmp(BlockBegin** a, BlockBegin** b) {
+return (*a)->block_id() - (*b)->block_id();
+}
+public:
+PredecessorValidator(IR* hir) {
+ResourceMark rm;
+_predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL);
+_blocks = new BlockList();
+int i;
+hir->start()->iterate_preorder(this);
+if (hir->code() != NULL) {
+assert(hir->code()->length() == _blocks->length(), "must match");
+for (i = 0; i < _blocks->length(); i++) {
+assert(hir->code()->contains(_blocks->at(i)), "should be in both lists");
+}
+}
+for (i = 0; i < _blocks->length(); i++) {
+BlockBegin* block = _blocks->at(i);
+BlockList* preds = _predecessors->at(block->block_id());
+if (preds == NULL) {
+assert(block->number_of_preds() == 0, "should be the same");
+continue;
+}
+// clone the pred list so we can mutate it
+BlockList* pred_copy = new BlockList();
+int j;
+for (j = 0; j < block->number_of_preds(); j++) {
+pred_copy->append(block->pred_at(j));
+}
+// sort them in the same order
+preds->sort(cmp);
+pred_copy->sort(cmp);
+int length = MIN2(preds->length(), block->number_of_preds());
+for (j = 0; j < block->number_of_preds(); j++) {
+assert(preds->at(j) == pred_copy->at(j), "must match");
+}
+assert(preds->length() == block->number_of_preds(), "should be the same");
+}
+}
+virtual void block_do(BlockBegin* block) {
+_blocks->append(block);
+BlockEnd* be = block->end();
+int n = be->number_of_sux();
+int i;
+for (i = 0; i < n; i++) {
+BlockBegin* sux = be->sux_at(i);
+assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler");
+BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL);
+if (preds == NULL) {
+preds = new BlockList();
+_predecessors->at_put(sux->block_id(), preds);
+}
+preds->append(block);
+}
+n = block->number_of_exception_handlers();
+for (i = 0; i < n; i++) {
+BlockBegin* sux = block->exception_handler_at(i);
+assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler");
+BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL);
+if (preds == NULL) {
+preds = new BlockList();
+_predecessors->at_put(sux->block_id(), preds);
+}
+preds->append(block);
+}
+}
+};
+void IR::verify() {
+#ifdef ASSERT
+PredecessorValidator pv(this);
+#endif
+}
+#endif // PRODUCT
+void SubstitutionResolver::substitute(Value* v) {
+Value v0 = *v;
+if (v0) {
+Value vs = v0->subst();
+if (vs != v0) {
+*v = v0->subst();
+}
+}
+}
+#ifdef ASSERT
+void check_substitute(Value* v) {
+Value v0 = *v;
+if (v0) {
+Value vs = v0->subst();
+assert(vs == v0, "missed substitution");
+}
+}
+#endif
+void SubstitutionResolver::block_do(BlockBegin* block) {
+Instruction* last = NULL;
+for (Instruction* n = block; n != NULL;) {
+n->values_do(substitute);
+// need to remove this instruction from the instruction stream
+if (n->subst() != n) {
+assert(last != NULL, "must have last");
+last->set_next(n->next(), n->next()->bci());
+} else {
+last = n;
+}
+n = last->next();
+}
+#ifdef ASSERT
+if (block->state()) block->state()->values_do(check_substitute);
+block->block_values_do(check_substitute);
+if (block->end() && block->end()->state()) block->end()->state()->values_do(check_substitute);
+#endif
+}

Mercurial > hg > truffle

comparison src/share/vm/c1/c1_IR.cpp @ 0:a61af66fc99e jdk7-b24