8155638: Resource allocated BitMaps are often cleared twice

Reviewed-by: neliasso, kvn

hotspot/src/cpu/x86/vm/c1_LinearScan_x86.cpp

@@ -68,7 +68,6 @@ void LinearScan::allocate_fpu_stack() {
       if (b->number_of_preds() > 1) {
         int id = b->first_lir_instruction_id();
         ResourceBitMap regs(FrameMap::nof_fpu_regs);
-        regs.clear();
 
         iw.walk_to(id);   // walk after the first instruction (always a label) of the block
         assert(iw.current_position() == id, "did not walk completely to id");

hotspot/src/share/vm/c1/c1_IR.cpp

@@ -147,10 +147,8 @@ IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMe
   _wrote_volatile     = false;
   _start              = NULL;
 
-  if (osr_bci == -1) {
-    _requires_phi_function.clear();
-  } else {
-        // selective creation of phi functions is not possibel in osr-methods
+  if (osr_bci != -1) {
+    // selective creation of phi functions is not possibel in osr-methods
     _requires_phi_function.set_range(0, method->max_locals());
   }
 
@@ -540,7 +538,6 @@ ComputeLinearScanOrder::ComputeLinearScanOrder(Compilation* c, BlockBegin* start
 {
   TRACE_LINEAR_SCAN(2, tty->print_cr("***** computing linear-scan block order"));
 
-  init_visited();
   count_edges(start_block, NULL);
 
   if (compilation()->is_profiling()) {
@@ -646,7 +643,6 @@ 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);

hotspot/src/share/vm/c1/c1_LIRGenerator.cpp

@@ -1387,7 +1387,6 @@ Instruction* LIRGenerator::instruction_for_vreg(int reg_num) {
 void LIRGenerator::set_vreg_flag(int vreg_num, VregFlag f) {
   if (_vreg_flags.size_in_bits() == 0) {
     BitMap2D temp(100, num_vreg_flags);
-    temp.clear();
     _vreg_flags = temp;
   }
   _vreg_flags.at_put_grow(vreg_num, f, true);

hotspot/src/share/vm/c1/c1_LinearScan.cpp

@@ -562,14 +562,13 @@ void LinearScan::compute_local_live_sets() {
   LIR_OpVisitState visitor;
 
   BitMap2D local_interval_in_loop = BitMap2D(_num_virtual_regs, num_loops());
-  local_interval_in_loop.clear();
 
   // iterate all blocks
   for (int i = 0; i < num_blocks; i++) {
     BlockBegin* block = block_at(i);
 
-    ResourceBitMap live_gen(live_size);  live_gen.clear();
-    ResourceBitMap live_kill(live_size); live_kill.clear();
+    ResourceBitMap live_gen(live_size);
+    ResourceBitMap live_kill(live_size);
 
     if (block->is_set(BlockBegin::exception_entry_flag)) {
       // Phi functions at the begin of an exception handler are
@@ -715,8 +714,8 @@ void LinearScan::compute_local_live_sets() {
 
     block->set_live_gen (live_gen);
     block->set_live_kill(live_kill);
-    block->set_live_in  (ResourceBitMap(live_size)); block->live_in().clear();
-    block->set_live_out (ResourceBitMap(live_size)); block->live_out().clear();
+    block->set_live_in  (ResourceBitMap(live_size));
+    block->set_live_out (ResourceBitMap(live_size));
 
     TRACE_LINEAR_SCAN(4, tty->print("live_gen  B%d ", block->block_id()); print_bitmap(block->live_gen()));
     TRACE_LINEAR_SCAN(4, tty->print("live_kill B%d ", block->block_id()); print_bitmap(block->live_kill()));
@@ -741,7 +740,7 @@ void LinearScan::compute_global_live_sets() {
   bool change_occurred;
   bool change_occurred_in_block;
   int  iteration_count = 0;
-  ResourceBitMap live_out(live_set_size()); live_out.clear(); // scratch set for calculations
+  ResourceBitMap live_out(live_set_size()); // scratch set for calculations
 
   // Perform a backward dataflow analysis to compute live_out and live_in for each block.
   // The loop is executed until a fixpoint is reached (no changes in an iteration)
@@ -827,7 +826,6 @@ void LinearScan::compute_global_live_sets() {
 
   // check that the live_in set of the first block is empty
   ResourceBitMap live_in_args(ir()->start()->live_in().size());
-  live_in_args.clear();
   if (!ir()->start()->live_in().is_same(live_in_args)) {
 #ifdef ASSERT
     tty->print_cr("Error: live_in set of first block must be empty (when this fails, virtual registers are used before they are defined)");
@@ -1774,8 +1772,8 @@ void LinearScan::resolve_data_flow() {
 
   int num_blocks = block_count();
   MoveResolver move_resolver(this);
-  ResourceBitMap block_completed(num_blocks);  block_completed.clear();
-  ResourceBitMap already_resolved(num_blocks); already_resolved.clear();
+  ResourceBitMap block_completed(num_blocks);
+  ResourceBitMap already_resolved(num_blocks);
 
   int i;
   for (i = 0; i < num_blocks; i++) {
@@ -3750,7 +3748,6 @@ void MoveResolver::verify_before_resolve() {
 
 
   ResourceBitMap used_regs(LinearScan::nof_regs + allocator()->frame_map()->argcount() + allocator()->max_spills());
-  used_regs.clear();
   if (!_multiple_reads_allowed) {
     for (i = 0; i < _mapping_from.length(); i++) {
       Interval* it = _mapping_from.at(i);
@@ -6319,7 +6316,6 @@ void ControlFlowOptimizer::delete_unnecessary_jumps(BlockList* code) {
 void ControlFlowOptimizer::delete_jumps_to_return(BlockList* code) {
 #ifdef ASSERT
   ResourceBitMap return_converted(BlockBegin::number_of_blocks());
-  return_converted.clear();
 #endif
 
   for (int i = code->length() - 1; i >= 0; i--) {

hotspot/src/share/vm/c1/c1_ValueSet.hpp

@@ -53,7 +53,6 @@ class ValueSet: public CompilationResourceObj {
 };
 
 inline ValueSet::ValueSet() : _map(Instruction::number_of_instructions()) {
-  _map.clear();
 }
 
 

hotspot/src/share/vm/ci/ciMethod.cpp

@@ -449,7 +449,6 @@ ResourceBitMap ciMethod::live_local_oops_at_bci(int bci) {
   OopMapCache::compute_one_oop_map(get_Method(), bci, &mask);
   int mask_size = max_locals();
   ResourceBitMap result(mask_size);
-  result.clear();
   int i;
   for (i = 0; i < mask_size ; i++ ) {
     if (mask.is_oop(i)) result.set_bit(i);

hotspot/src/share/vm/compiler/methodLiveness.cpp

@@ -137,11 +137,6 @@ MethodLiveness::MethodLiveness(Arena* arena, ciMethod* method)
   _arena = arena;
   _method = method;
   _bit_map_size_bits = method->max_locals();
-
-
-#ifdef COMPILER1
-  _bci_block_start.clear();
-#endif
 }
 
 void MethodLiveness::compute_liveness() {
@@ -587,14 +582,6 @@ MethodLiveness::BasicBlock::BasicBlock(MethodLiveness *analyzer, int start, int
     new (analyzer->arena()) GrowableArray<MethodLiveness::BasicBlock*>(analyzer->arena(), 5, 0, NULL);
   _exception_predecessors =
     new (analyzer->arena()) GrowableArray<MethodLiveness::BasicBlock*>(analyzer->arena(), 5, 0, NULL);
-  _normal_exit.clear();
-  _exception_exit.clear();
-  _entry.clear();
-
-  // this initialization is not strictly necessary.
-  // _gen and _kill are cleared at the beginning of compute_gen_kill_range()
-  _gen.clear();
-  _kill.clear();
 }
 
 
@@ -1020,7 +1007,6 @@ MethodLivenessResult MethodLiveness::BasicBlock::get_liveness_at(ciMethod* metho
     _last_bci = bci;
   }
 
-  answer.clear();
   answer.set_union(_normal_exit);
   answer.set_difference(_kill);
   answer.set_union(_gen);

hotspot/src/share/vm/utilities/bitMap.hpp

@@ -435,7 +435,6 @@ class BitMap2D VALUE_OBJ_CLASS_SPEC {
   void clear_bit(idx_t slot_index, idx_t bit_within_slot_index);
   void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value);
   void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value);
-  void clear();
 };
 
 // Closure for iterating over BitMaps

hotspot/src/share/vm/utilities/bitMap.inline.hpp

@@ -367,8 +367,4 @@ inline void BitMap2D::at_put_grow(idx_t slot_index, idx_t bit_within_slot_index,
   _map.at_put(bit, value);
 }
 
-inline void BitMap2D::clear() {
-  _map.clear();
-}
-
 #endif // SHARE_VM_UTILITIES_BITMAP_INLINE_HPP