/* * Copyright (c) 1999, 2022, 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. *
*/
// 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()) { returntrue;
}
for (int i = 0; i < length(); i++) {
XHandler* handler = handler_at(i); if (handler->is_catch_all()) { // catch of ANY returntrue;
}
ciInstanceKlass* handler_klass = handler->catch_klass(); // if it's unknown it might be catchable if (!handler_klass->is_loaded()) { returntrue;
} // if the throw type is definitely a subtype of the catch type // then it can be caught. if (klass->is_subtype_of(handler_klass)) { returntrue;
} 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)) { returntrue;
}
}
}
returnfalse;
}
bool XHandlers::equals(XHandlers* others) const { if (others == NULL) returnfalse; if (length() != others->length()) returnfalse;
for (int i = 0; i < length(); i++) { if (!handler_at(i)->equals(others->handler_at(i))) returnfalse;
} returntrue;
}
if (osr_bci != -1) { // 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;
}
// 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()); bool reexecute = _force_reexecute || _scope_debug_info->should_reexecute();
_scope_debug_info->record_debug_info(recorder, pc_offset, reexecute, _is_method_handle_invoke);
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");
VMReg name = frame_map()->regname(opr);
_oop_map->set_oop(name);
}
// Mirror the stack size calculation in the deopt code // How much stack space would we need at this point in the program in // case of deoptimization? int CodeEmitInfo::interpreter_frame_size() const {
ValueStack* state = _stack; int size = 0; int callee_parameters = 0; int callee_locals = 0; int extra_args = state->scope()->method()->max_stack() - state->stack_size();
while (state != NULL) { int locks = state->locks_size(); int temps = state->stack_size(); bool is_top_frame = (state == _stack);
ciMethod* method = state->scope()->method();
int frame_size = BytesPerWord * Interpreter::size_activation(method->max_stack(),
temps + callee_parameters,
extra_args,
locks,
callee_parameters,
callee_locals,
is_top_frame);
size += frame_size;
class UseCountComputer: public ValueVisitor, BlockClosure { private: void visit(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)->is_linked() && (*n)->can_be_linked()) {
assert(false, "a node was not appended to the graph");
Compilation::current()->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++;
}
Values* worklist; int depth; enum {
max_recurse_depth = 20
};
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(this); // 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(this);
}
}
depth--;
}
void block_do(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");
}
UseCountComputer() {
worklist = new Values();
depth = 0;
}
// helper macro for short definition of trace-output inside code #ifdef ASSERT #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
ResourceBitMap _visited_blocks; // used for recursive processing of blocks
ResourceBitMap _active_blocks; // used for recursive processing of blocks
ResourceBitMap _dominator_blocks; // temporary 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)
BlockList _loop_headers;
Compilation* _compilation;
// 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);
// 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");
// When a loop header is also the start of an exception handler, then the backward branch is // an exception edge. Because such edges are usually critical edges which cannot be split, the // loop must be excluded here from processing. if (cur->is_set(BlockBegin::exception_entry_flag)) { // Make sure that dominators are correct in this weird situation
_iterative_dominators = true; return;
}
assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur, "loop end blocks must have one successor (critical edges are split)");
_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));
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 multiple 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));
BlockBegin *loop_header = _loop_headers.at(i);
assert(loop_header->is_set(BlockBegin::linear_scan_loop_header_flag), "Must be loop header");
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_impl(BlockBegin* cur, BlockBegin* parent) { // Mark as visited to avoid recursive calls with same parent
set_visited(cur);
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);
} elseif (!(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())); // Does not hold for exception blocks
assert(cur->number_of_preds() > 1 || cur->is_set(BlockBegin::exception_entry_flag), "");
cur->set_dominator(common_dominator(cur->dominator(), parent));
}
// Additional edge to xhandler of all our successors // range check elimination needs that the state at the end of a // block be valid in every block it dominates so cur must dominate // the exception handlers of its successors. int num_cur_xhandler = cur->number_of_exception_handlers(); for (int j = 0; j < num_cur_xhandler; j++) {
BlockBegin* xhandler = cur->exception_handler_at(j); if (!is_visited(xhandler)) {
compute_dominator_impl(xhandler, 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 necessary for the (very rare) case that two successive 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 preferred 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) { returnfalse;
}
assert(_linear_scan_order->find(cur) == -1, "block already processed (block can be ready only once)");
assert(_work_list.find(cur) == -1, "block already in work-list (block can be ready only once)"); returntrue;
}
void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) {
assert(_work_list.find(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
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->find(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, tty->print_cr("----- 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, "successor of osr entry must have two predecessors (otherwise it is not present in normal control flow");
// 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); if (ready_for_processing(sux)) {
sort_into_work_list(sux);
}
}
} while (_work_list.length() > 0);
}
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();
if (block->is_set(BlockBegin::exception_entry_flag)) {
dominator = common_dominator(dominator, pred); int num_pred_preds = pred->number_of_preds(); for (int k = 0; k < num_pred_preds; k++) {
dominator = common_dominator(dominator, pred->pred_at(k));
}
} else {
dominator = common_dominator(dominator, pred);
}
}
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()));
// 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");
// Add Blocks to dominates-Array int num_blocks = _linear_scan_order->length(); for (int i = 0; i < num_blocks; i++) {
BlockBegin* block = _linear_scan_order->at(i);
BlockBegin *dom = block->dominator(); if (dom) {
assert(dom->dominator_depth() != -1, "Dominator must have been visited before");
dom->dominates()->append(block);
block->set_dominator_depth(dom->dominator_depth() + 1);
} else {
block->set_dominator_depth(0);
}
}
}
#ifdef ASSERT 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);
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);
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->find(sux), "incorrect linear_scan_number"); if (!sux->is_set(BlockBegin::backward_branch_target_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), "successive 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->find(pred), "incorrect linear_scan_number"); if (!cur->is_set(BlockBegin::backward_branch_target_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), "successive 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");
} // Assertion does not hold for exception handlers
assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0) || cur->is_set(BlockBegin::exception_entry_flag), "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// ASSERT
void IR::compute_code() {
assert(is_valid(), "IR must be valid");
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);
}
#ifdef ASSERT class EndNotNullValidator : public BlockClosure { public: virtualvoid block_do(BlockBegin* block) {
assert(block->end() != NULL, "Expect block end to exist.");
}
};
class XentryFlagValidator : public BlockClosure { public: virtualvoid block_do(BlockBegin* block) { for (int i = 0; i < block->end()->number_of_sux(); i++) {
assert(!block->end()->sux_at(i)->is_set(BlockBegin::exception_entry_flag), "must not be xhandler");
} for (int i = 0; i < block->number_of_exception_handlers(); i++) {
assert(block->exception_handler_at(i)->is_set(BlockBegin::exception_entry_flag), "must be xhandler");
}
}
};
typedef GrowableArray<BlockList*> BlockListList;
// Validation goals: // - code() length == blocks length // - code() contents == blocks content // - Each block's computed predecessors match sux lists (length) // - Each block's computed predecessors match sux lists (set content) class PredecessorAndCodeValidator : public BlockClosure { private:
BlockListList* _predecessors; // Each index i will hold predecessors of block with id i
BlockList* _blocks;
staticint cmp(BlockBegin** a, BlockBegin** b) { return (*a)->block_id() - (*b)->block_id();
}
public:
PredecessorAndCodeValidator(IR* hir) {
ResourceMark rm;
_predecessors = new BlockListList(BlockBegin::number_of_blocks(), BlockBegin::number_of_blocks(), NULL);
_blocks = new BlockList(BlockBegin::number_of_blocks());
hir->start()->iterate_preorder(this); if (hir->code() != NULL) {
assert(hir->code()->length() == _blocks->length(), "must match"); for (int i = 0; i < _blocks->length(); i++) {
assert(hir->code()->contains(_blocks->at(i)), "should be in both lists");
}
}
for (int i = 0; i < _blocks->length(); i++) {
BlockBegin* block = _blocks->at(i);
verify_block_preds_against_collected_preds(block);
}
}
void verify_block_preds_against_collected_preds(const BlockBegin* block) const {
BlockList* preds = _predecessors->at(block->block_id()); if (preds == NULL) {
assert(block->number_of_preds() == 0, "should be the same"); return;
}
assert(preds->length() == block->number_of_preds(), "should be the same");
// clone the pred list so we can mutate it
BlockList* pred_copy = new BlockList(); for (int 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); for (int j = 0; j < block->number_of_preds(); j++) {
assert(preds->at(j) == pred_copy->at(j), "must match");
}
}
};
class VerifyBlockBeginField : public BlockClosure { public: virtualvoid block_do(BlockBegin* block) { for (Instruction* cur = block; cur != NULL; cur = cur->next()) {
assert(cur->block() == block, "Block begin is not correct");
}
}
};
class ValidateEdgeMutuality : public BlockClosure { public: virtualvoid block_do(BlockBegin* block) { for (int i = 0; i < block->end()->number_of_sux(); i++) {
assert(block->end()->sux_at(i)->is_predecessor(block), "Block's successor should have it as predecessor");
}
for (int i = 0; i < block->number_of_exception_handlers(); i++) {
assert(block->exception_handler_at(i)->is_predecessor(block), "Block's exception handler should have it as predecessor");
}
for (int i = 0; i < block->number_of_preds(); i++) {
assert(block->pred_at(i) != NULL, "Predecessor must exist");
assert(block->pred_at(i)->end() != NULL, "Predecessor end must exist"); bool is_sux = block->pred_at(i)->end()->is_sux(block); bool is_xhandler = block->pred_at(i)->is_exception_handler(block);
assert(is_sux || is_xhandler, "Block's predecessor should have it as successor or xhandler");
}
}
};
void IR::expand_with_neighborhood(BlockList& blocks) { int original_size = blocks.length(); for (int h = 0; h < original_size; h++) {
BlockBegin* block = blocks.at(h);
for (int i = 0; i < block->end()->number_of_sux(); i++) { if (!blocks.contains(block->end()->sux_at(i))) {
blocks.append(block->end()->sux_at(i));
}
}
for (int i = 0; i < block->number_of_preds(); i++) { if (!blocks.contains(block->pred_at(i))) {
blocks.append(block->pred_at(i));
}
}
for (int i = 0; i < block->number_of_exception_handlers(); i++) { if (!blocks.contains(block->exception_handler_at(i))) {
blocks.append(block->exception_handler_at(i));
}
}
}
}
void SubstitutionResolver::visit(Value* v) {
Value v0 = *v; if (v0) {
Value vs = v0->subst(); if (vs != v0) {
*v = v0->subst();
}
}
}
#ifdef ASSERT class SubstitutionChecker: public ValueVisitor { void visit(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(this); // need to remove this instruction from the instruction stream if (n->subst() != n) {
guarantee(last != NULL, "must have last");
last->set_next(n->next());
} else {
last = n;
}
n = last->next();
}
#ifdef ASSERT
SubstitutionChecker check_substitute; 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
}
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