jdk8-mips64-public/hotspot: src/share/vm/opto/lcm.cpp@c1c199dde5c9 (annotated)

src/share/vm/opto/lcm.cpp@c1c199dde5c9 (annotated)

src/share/vm/opto/lcm.cpp

Wed, 03 Jun 2015 14:22:57 +0200

author: roland
date: Wed, 03 Jun 2015 14:22:57 +0200
changeset 7859: c1c199dde5c9
parent 7598: ddce0b7cee93
child 7994: 04ff2f6cd0eb
child 8316: 626f594dffa6
permissions: -rw-r--r--

8077504: Unsafe load can loose control dependency and cause crash
Summary: Node::depends_only_on_test() should return false for Unsafe loads
Reviewed-by: kvn, adinn

 /*
  * Copyright (c) 1998, 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 "memory/allocation.inline.hpp"
 #include "opto/block.hpp"
 #include "opto/c2compiler.hpp"
 #include "opto/callnode.hpp"
 #include "opto/cfgnode.hpp"
 #include "opto/machnode.hpp"
 #include "opto/runtime.hpp"
 #if defined AD_MD_HPP
 # include AD_MD_HPP
 #elif defined TARGET_ARCH_MODEL_x86_32
 # include "adfiles/ad_x86_32.hpp"
 #elif defined TARGET_ARCH_MODEL_x86_64
 # include "adfiles/ad_x86_64.hpp"
 #elif defined TARGET_ARCH_MODEL_sparc
 # include "adfiles/ad_sparc.hpp"
 #elif defined TARGET_ARCH_MODEL_zero
 # include "adfiles/ad_zero.hpp"
 #elif defined TARGET_ARCH_MODEL_ppc_64
 # include "adfiles/ad_ppc_64.hpp"
 #endif
 // Optimization - Graph Style
 // Check whether val is not-null-decoded compressed oop,
 // i.e. will grab into the base of the heap if it represents NULL.
 static bool accesses_heap_base_zone(Node *val) {
   if (Universe::narrow_oop_base() > 0) { // Implies UseCompressedOops.
     if (val && val->is_Mach()) {
       if (val->as_Mach()->ideal_Opcode() == Op_DecodeN) {
         // This assumes all Decodes with TypePtr::NotNull are matched to nodes that
         // decode NULL to point to the heap base (Decode_NN).
         if (val->bottom_type()->is_oopptr()->ptr() == TypePtr::NotNull) {
           return true;
         }
       }
       // Must recognize load operation with Decode matched in memory operand.
       // We should not reach here exept for PPC/AIX, as os::zero_page_read_protected()
       // returns true everywhere else. On PPC, no such memory operands
       // exist, therefore we did not yet implement a check for such operands.
       NOT_AIX(Unimplemented());
     }
   }
   return false;
 }
 static bool needs_explicit_null_check_for_read(Node *val) {
   // On some OSes (AIX) the page at address 0 is only write protected.
   // If so, only Store operations will trap.
   if (os::zero_page_read_protected()) {
     return false;  // Implicit null check will work.
   }
   // Also a read accessing the base of a heap-based compressed heap will trap.
   if (accesses_heap_base_zone(val) &&                    // Hits the base zone page.
       Universe::narrow_oop_use_implicit_null_checks()) { // Base zone page is protected.
     return false;
   }
   return true;
 }
 //------------------------------implicit_null_check----------------------------
 // Detect implicit-null-check opportunities.  Basically, find NULL checks
 // with suitable memory ops nearby.  Use the memory op to do the NULL check.
 // I can generate a memory op if there is not one nearby.
 // The proj is the control projection for the not-null case.
 // The val is the pointer being checked for nullness or
 // decodeHeapOop_not_null node if it did not fold into address.
 void PhaseCFG::implicit_null_check(Block* block, Node *proj, Node *val, int allowed_reasons) {
   // Assume if null check need for 0 offset then always needed
   // Intel solaris doesn't support any null checks yet and no
   // mechanism exists (yet) to set the switches at an os_cpu level
   if( !ImplicitNullChecks || MacroAssembler::needs_explicit_null_check(0)) return;
   // Make sure the ptr-is-null path appears to be uncommon!
   float f = block->end()->as_MachIf()->_prob;
   if( proj->Opcode() == Op_IfTrue ) f = 1.0f - f;
   if( f > PROB_UNLIKELY_MAG(4) ) return;
   uint bidx = 0;                // Capture index of value into memop
   bool was_store;               // Memory op is a store op
   // Get the successor block for if the test ptr is non-null
   Block* not_null_block;  // this one goes with the proj
   Block* null_block;
   if (block->get_node(block->number_of_nodes()-1) == proj) {
     null_block     = block->_succs[0];
     not_null_block = block->_succs[1];
   } else {
     assert(block->get_node(block->number_of_nodes()-2) == proj, "proj is one or the other");
     not_null_block = block->_succs[0];
     null_block     = block->_succs[1];
   }
   while (null_block->is_Empty() == Block::empty_with_goto) {
     null_block     = null_block->_succs[0];
   }
   // Search the exception block for an uncommon trap.
   // (See Parse::do_if and Parse::do_ifnull for the reason
   // we need an uncommon trap.  Briefly, we need a way to
   // detect failure of this optimization, as in 6366351.)
   {
     bool found_trap = false;
     for (uint i1 = 0; i1 < null_block->number_of_nodes(); i1++) {
       Node* nn = null_block->get_node(i1);
       if (nn->is_MachCall() &&
           nn->as_MachCall()->entry_point() == SharedRuntime::uncommon_trap_blob()->entry_point()) {
         const Type* trtype = nn->in(TypeFunc::Parms)->bottom_type();
         if (trtype->isa_int() && trtype->is_int()->is_con()) {
           jint tr_con = trtype->is_int()->get_con();
           Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(tr_con);
           Deoptimization::DeoptAction action = Deoptimization::trap_request_action(tr_con);
           assert((int)reason < (int)BitsPerInt, "recode bit map");
           if (is_set_nth_bit(allowed_reasons, (int) reason)
               && action != Deoptimization::Action_none) {
             // This uncommon trap is sure to recompile, eventually.
             // When that happens, C->too_many_traps will prevent
             // this transformation from happening again.
             found_trap = true;
           }
         }
         break;
       }
     }
     if (!found_trap) {
       // We did not find an uncommon trap.
       return;
     }
   }
   // Check for decodeHeapOop_not_null node which did not fold into address
   bool is_decoden = ((intptr_t)val) & 1;
   val = (Node*)(((intptr_t)val) & ~1);
   assert(!is_decoden || (val->in(0) == NULL) && val->is_Mach() &&
          (val->as_Mach()->ideal_Opcode() == Op_DecodeN), "sanity");
   // Search the successor block for a load or store who's base value is also
   // the tested value.  There may be several.
   Node_List *out = new Node_List(Thread::current()->resource_area());
   MachNode *best = NULL;        // Best found so far
   for (DUIterator i = val->outs(); val->has_out(i); i++) {
     Node *m = val->out(i);
     if( !m->is_Mach() ) continue;
     MachNode *mach = m->as_Mach();
     was_store = false;
     int iop = mach->ideal_Opcode();
     switch( iop ) {
     case Op_LoadB:
     case Op_LoadUB:
     case Op_LoadUS:
     case Op_LoadD:
     case Op_LoadF:
     case Op_LoadI:
     case Op_LoadL:
     case Op_LoadP:
     case Op_LoadN:
     case Op_LoadS:
     case Op_LoadKlass:
     case Op_LoadNKlass:
     case Op_LoadRange:
     case Op_LoadD_unaligned:
     case Op_LoadL_unaligned:
       assert(mach->in(2) == val, "should be address");
       break;
     case Op_StoreB:
     case Op_StoreC:
     case Op_StoreCM:
     case Op_StoreD:
     case Op_StoreF:
     case Op_StoreI:
     case Op_StoreL:
     case Op_StoreP:
     case Op_StoreN:
     case Op_StoreNKlass:
       was_store = true;         // Memory op is a store op
       // Stores will have their address in slot 2 (memory in slot 1).
       // If the value being nul-checked is in another slot, it means we
       // are storing the checked value, which does NOT check the value!
       if( mach->in(2) != val ) continue;
       break;                    // Found a memory op?
     case Op_StrComp:
     case Op_StrEquals:
     case Op_StrIndexOf:
     case Op_AryEq:
     case Op_EncodeISOArray:
       // Not a legit memory op for implicit null check regardless of
       // embedded loads
       continue;
     default:                    // Also check for embedded loads
       if( !mach->needs_anti_dependence_check() )
         continue;               // Not an memory op; skip it
       if( must_clone[iop] ) {
         // Do not move nodes which produce flags because
         // RA will try to clone it to place near branch and
         // it will cause recompilation, see clone_node().
         continue;
       }
       {
         // Check that value is used in memory address in
         // instructions with embedded load (CmpP val1,(val2+off)).
         Node* base;
         Node* index;
         const MachOper* oper = mach->memory_inputs(base, index);
         if (oper == NULL || oper == (MachOper*)-1) {
           continue;             // Not an memory op; skip it
         }
         if (val == base ||
             val == index && val->bottom_type()->isa_narrowoop()) {
           break;                // Found it
         } else {
           continue;             // Skip it
         }
       }
       break;
     }
     // On some OSes (AIX) the page at address 0 is only write protected.
     // If so, only Store operations will trap.
     // But a read accessing the base of a heap-based compressed heap will trap.
     if (!was_store && needs_explicit_null_check_for_read(val)) {
       continue;
     }
     // check if the offset is not too high for implicit exception
     {
       intptr_t offset = 0;
       const TypePtr *adr_type = NULL;  // Do not need this return value here
       const Node* base = mach->get_base_and_disp(offset, adr_type);
       if (base == NULL || base == NodeSentinel) {
         // Narrow oop address doesn't have base, only index
         if( val->bottom_type()->isa_narrowoop() &&
             MacroAssembler::needs_explicit_null_check(offset) )
           continue;             // Give up if offset is beyond page size
         // cannot reason about it; is probably not implicit null exception
       } else {
         const TypePtr* tptr;
         if (UseCompressedOops && (Universe::narrow_oop_shift() == 0 ||
                                   Universe::narrow_klass_shift() == 0)) {
           // 32-bits narrow oop can be the base of address expressions
           tptr = base->get_ptr_type();
         } else {
           // only regular oops are expected here
           tptr = base->bottom_type()->is_ptr();
         }
         // Give up if offset is not a compile-time constant
         if( offset == Type::OffsetBot || tptr->_offset == Type::OffsetBot )
           continue;
         offset += tptr->_offset; // correct if base is offseted
         if( MacroAssembler::needs_explicit_null_check(offset) )
           continue;             // Give up is reference is beyond 4K page size
       }
     }
     // Check ctrl input to see if the null-check dominates the memory op
     Block *cb = get_block_for_node(mach);
     cb = cb->_idom;             // Always hoist at least 1 block
     if( !was_store ) {          // Stores can be hoisted only one block
       while( cb->_dom_depth > (block->_dom_depth + 1))
         cb = cb->_idom;         // Hoist loads as far as we want
       // The non-null-block should dominate the memory op, too. Live
       // range spilling will insert a spill in the non-null-block if it is
       // needs to spill the memory op for an implicit null check.
       if (cb->_dom_depth == (block->_dom_depth + 1)) {
         if (cb != not_null_block) continue;
         cb = cb->_idom;
       }
     }
     if( cb != block ) continue;
     // Found a memory user; see if it can be hoisted to check-block
     uint vidx = 0;              // Capture index of value into memop
     uint j;
     for( j = mach->req()-1; j > 0; j-- ) {
       if( mach->in(j) == val ) {
         vidx = j;
         // Ignore DecodeN val which could be hoisted to where needed.
         if( is_decoden ) continue;
       }
       // Block of memory-op input
       Block *inb = get_block_for_node(mach->in(j));
       Block *b = block;          // Start from nul check
       while( b != inb && b->_dom_depth > inb->_dom_depth )
         b = b->_idom;           // search upwards for input
       // See if input dominates null check
       if( b != inb )
         break;
     }
     if( j > 0 )
       continue;
     Block *mb = get_block_for_node(mach);
     // Hoisting stores requires more checks for the anti-dependence case.
     // Give up hoisting if we have to move the store past any load.
     if( was_store ) {
       Block *b = mb;            // Start searching here for a local load
       // mach use (faulting) trying to hoist
       // n might be blocker to hoisting
       while( b != block ) {
         uint k;
         for( k = 1; k < b->number_of_nodes(); k++ ) {
           Node *n = b->get_node(k);
           if( n->needs_anti_dependence_check() &&
               n->in(LoadNode::Memory) == mach->in(StoreNode::Memory) )
             break;              // Found anti-dependent load
         }
         if( k < b->number_of_nodes() )
           break;                // Found anti-dependent load
         // Make sure control does not do a merge (would have to check allpaths)
         if( b->num_preds() != 2 ) break;
         b = get_block_for_node(b->pred(1)); // Move up to predecessor block
       }
       if( b != block ) continue;
     }
     // Make sure this memory op is not already being used for a NullCheck
     Node *e = mb->end();
     if( e->is_MachNullCheck() && e->in(1) == mach )
       continue;                 // Already being used as a NULL check
     // Found a candidate!  Pick one with least dom depth - the highest
     // in the dom tree should be closest to the null check.
     if (best == NULL || get_block_for_node(mach)->_dom_depth < get_block_for_node(best)->_dom_depth) {
       best = mach;
       bidx = vidx;
     }
   }
   // No candidate!
   if (best == NULL) {
     return;
   }
   // ---- Found an implicit null check
   extern int implicit_null_checks;
   implicit_null_checks++;
   if( is_decoden ) {
     // Check if we need to hoist decodeHeapOop_not_null first.
     Block *valb = get_block_for_node(val);
     if( block != valb && block->_dom_depth < valb->_dom_depth ) {
       // Hoist it up to the end of the test block.
       valb->find_remove(val);
       block->add_inst(val);
       map_node_to_block(val, block);
       // DecodeN on x86 may kill flags. Check for flag-killing projections
       // that also need to be hoisted.
       for (DUIterator_Fast jmax, j = val->fast_outs(jmax); j < jmax; j++) {
         Node* n = val->fast_out(j);
         if( n->is_MachProj() ) {
           get_block_for_node(n)->find_remove(n);
           block->add_inst(n);
           map_node_to_block(n, block);
         }
       }
     }
   }
   // Hoist the memory candidate up to the end of the test block.
   Block *old_block = get_block_for_node(best);
   old_block->find_remove(best);
   block->add_inst(best);
   map_node_to_block(best, block);
   // Move the control dependence
   if (best->in(0) && best->in(0) == old_block->head())
     best->set_req(0, block->head());
   // Check for flag-killing projections that also need to be hoisted
   // Should be DU safe because no edge updates.
   for (DUIterator_Fast jmax, j = best->fast_outs(jmax); j < jmax; j++) {
     Node* n = best->fast_out(j);
     if( n->is_MachProj() ) {
       get_block_for_node(n)->find_remove(n);
       block->add_inst(n);
       map_node_to_block(n, block);
     }
   }
   // proj==Op_True --> ne test; proj==Op_False --> eq test.
   // One of two graph shapes got matched:
   //   (IfTrue  (If (Bool NE (CmpP ptr NULL))))
   //   (IfFalse (If (Bool EQ (CmpP ptr NULL))))
   // NULL checks are always branch-if-eq.  If we see a IfTrue projection
   // then we are replacing a 'ne' test with a 'eq' NULL check test.
   // We need to flip the projections to keep the same semantics.
   if( proj->Opcode() == Op_IfTrue ) {
     // Swap order of projections in basic block to swap branch targets
     Node *tmp1 = block->get_node(block->end_idx()+1);
     Node *tmp2 = block->get_node(block->end_idx()+2);
     block->map_node(tmp2, block->end_idx()+1);
     block->map_node(tmp1, block->end_idx()+2);
     Node *tmp = new (C) Node(C->top()); // Use not NULL input
     tmp1->replace_by(tmp);
     tmp2->replace_by(tmp1);
     tmp->replace_by(tmp2);
     tmp->destruct();
   }
   // Remove the existing null check; use a new implicit null check instead.
   // Since schedule-local needs precise def-use info, we need to correct
   // it as well.
   Node *old_tst = proj->in(0);
   MachNode *nul_chk = new (C) MachNullCheckNode(old_tst->in(0),best,bidx);
   block->map_node(nul_chk, block->end_idx());
   map_node_to_block(nul_chk, block);
   // Redirect users of old_test to nul_chk
   for (DUIterator_Last i2min, i2 = old_tst->last_outs(i2min); i2 >= i2min; --i2)
     old_tst->last_out(i2)->set_req(0, nul_chk);
   // Clean-up any dead code
   for (uint i3 = 0; i3 < old_tst->req(); i3++) {
     Node* in = old_tst->in(i3);
     old_tst->set_req(i3, NULL);
     if (in->outcnt() == 0) {
       // Remove dead input node
       in->disconnect_inputs(NULL, C);
       block->find_remove(in);
     }
   }
   latency_from_uses(nul_chk);
   latency_from_uses(best);
 }
 //------------------------------select-----------------------------------------
 // Select a nice fellow from the worklist to schedule next. If there is only
 // one choice, then use it. Projections take top priority for correctness
 // reasons - if I see a projection, then it is next.  There are a number of
 // other special cases, for instructions that consume condition codes, et al.
 // These are chosen immediately. Some instructions are required to immediately
 // precede the last instruction in the block, and these are taken last. Of the
 // remaining cases (most), choose the instruction with the greatest latency
 // (that is, the most number of pseudo-cycles required to the end of the
 // routine). If there is a tie, choose the instruction with the most inputs.
 Node* PhaseCFG::select(Block* block, Node_List &worklist, GrowableArray<int> &ready_cnt, VectorSet &next_call, uint sched_slot) {
   // If only a single entry on the stack, use it
   uint cnt = worklist.size();
   if (cnt == 1) {
     Node *n = worklist[0];
     worklist.map(0,worklist.pop());
     return n;
   }
   uint choice  = 0; // Bigger is most important
   uint latency = 0; // Bigger is scheduled first
   uint score   = 0; // Bigger is better
   int idx = -1;     // Index in worklist
   int cand_cnt = 0; // Candidate count
   for( uint i=0; i<cnt; i++ ) { // Inspect entire worklist
     // Order in worklist is used to break ties.
     // See caller for how this is used to delay scheduling
     // of induction variable increments to after the other
     // uses of the phi are scheduled.
     Node *n = worklist[i];      // Get Node on worklist
     int iop = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : 0;
     if( n->is_Proj() ||         // Projections always win
         n->Opcode()== Op_Con || // So does constant 'Top'
         iop == Op_CreateEx ||   // Create-exception must start block
         iop == Op_CheckCastPP
         ) {
       worklist.map(i,worklist.pop());
       return n;
     }
     // Final call in a block must be adjacent to 'catch'
     Node *e = block->end();
     if( e->is_Catch() && e->in(0)->in(0) == n )
       continue;
     // Memory op for an implicit null check has to be at the end of the block
     if( e->is_MachNullCheck() && e->in(1) == n )
       continue;
     // Schedule IV increment last.
     if (e->is_Mach() && e->as_Mach()->ideal_Opcode() == Op_CountedLoopEnd &&
         e->in(1)->in(1) == n && n->is_iteratively_computed())
       continue;
     uint n_choice  = 2;
     // See if this instruction is consumed by a branch. If so, then (as the
     // branch is the last instruction in the basic block) force it to the
     // end of the basic block
     if ( must_clone[iop] ) {
       // See if any use is a branch
       bool found_machif = false;
       for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
         Node* use = n->fast_out(j);
         // The use is a conditional branch, make them adjacent
         if (use->is_MachIf() && get_block_for_node(use) == block) {
           found_machif = true;
           break;
         }
         // More than this instruction pending for successor to be ready,
         // don't choose this if other opportunities are ready
         if (ready_cnt.at(use->_idx) > 1)
           n_choice = 1;
       }
       // loop terminated, prefer not to use this instruction
       if (found_machif)
         continue;
     }
     // See if this has a predecessor that is "must_clone", i.e. sets the
     // condition code. If so, choose this first
     for (uint j = 0; j < n->req() ; j++) {
       Node *inn = n->in(j);
       if (inn) {
         if (inn->is_Mach() && must_clone[inn->as_Mach()->ideal_Opcode()] ) {
           n_choice = 3;
           break;
         }
       }
     }
     // MachTemps should be scheduled last so they are near their uses
     if (n->is_MachTemp()) {
       n_choice = 1;
     }
     uint n_latency = get_latency_for_node(n);
     uint n_score   = n->req();   // Many inputs get high score to break ties
     // Keep best latency found
     cand_cnt++;
     if (choice < n_choice ||
         (choice == n_choice &&
          ((StressLCM && Compile::randomized_select(cand_cnt)) ||
           (!StressLCM &&
            (latency < n_latency ||
             (latency == n_latency &&
              (score < n_score))))))) {
       choice  = n_choice;
       latency = n_latency;
       score   = n_score;
       idx     = i;               // Also keep index in worklist
     }
   } // End of for all ready nodes in worklist
   assert(idx >= 0, "index should be set");
   Node *n = worklist[(uint)idx];      // Get the winner
   worklist.map((uint)idx, worklist.pop());     // Compress worklist
   return n;
 }
 //------------------------------set_next_call----------------------------------
 void PhaseCFG::set_next_call(Block* block, Node* n, VectorSet& next_call) {
   if( next_call.test_set(n->_idx) ) return;
   for( uint i=0; i<n->len(); i++ ) {
     Node *m = n->in(i);
     if( !m ) continue;  // must see all nodes in block that precede call
     if (get_block_for_node(m) == block) {
       set_next_call(block, m, next_call);
     }
   }
 }
 //------------------------------needed_for_next_call---------------------------
 // Set the flag 'next_call' for each Node that is needed for the next call to
 // be scheduled.  This flag lets me bias scheduling so Nodes needed for the
 // next subroutine call get priority - basically it moves things NOT needed
 // for the next call till after the call.  This prevents me from trying to
 // carry lots of stuff live across a call.
 void PhaseCFG::needed_for_next_call(Block* block, Node* this_call, VectorSet& next_call) {
   // Find the next control-defining Node in this block
   Node* call = NULL;
   for (DUIterator_Fast imax, i = this_call->fast_outs(imax); i < imax; i++) {
     Node* m = this_call->fast_out(i);
     if (get_block_for_node(m) == block && // Local-block user
         m != this_call &&       // Not self-start node
         m->is_MachCall()) {
       call = m;
       break;
     }
   }
   if (call == NULL)  return;    // No next call (e.g., block end is near)
   // Set next-call for all inputs to this call
   set_next_call(block, call, next_call);
 }
 //------------------------------add_call_kills-------------------------------------
 // helper function that adds caller save registers to MachProjNode
 static void add_call_kills(MachProjNode *proj, RegMask& regs, const char* save_policy, bool exclude_soe) {
   // Fill in the kill mask for the call
   for( OptoReg::Name r = OptoReg::Name(0); r < _last_Mach_Reg; r=OptoReg::add(r,1) ) {
     if( !regs.Member(r) ) {     // Not already defined by the call
       // Save-on-call register?
       if ((save_policy[r] == 'C') ||
           (save_policy[r] == 'A') ||
           ((save_policy[r] == 'E') && exclude_soe)) {
         proj->_rout.Insert(r);
       }
     }
   }
 }
 //------------------------------sched_call-------------------------------------
 uint PhaseCFG::sched_call(Block* block, uint node_cnt, Node_List& worklist, GrowableArray<int>& ready_cnt, MachCallNode* mcall, VectorSet& next_call) {
   RegMask regs;
   // Schedule all the users of the call right now.  All the users are
   // projection Nodes, so they must be scheduled next to the call.
   // Collect all the defined registers.
   for (DUIterator_Fast imax, i = mcall->fast_outs(imax); i < imax; i++) {
     Node* n = mcall->fast_out(i);
     assert( n->is_MachProj(), "" );
     int n_cnt = ready_cnt.at(n->_idx)-1;
     ready_cnt.at_put(n->_idx, n_cnt);
     assert( n_cnt == 0, "" );
     // Schedule next to call
     block->map_node(n, node_cnt++);
     // Collect defined registers
     regs.OR(n->out_RegMask());
     // Check for scheduling the next control-definer
     if( n->bottom_type() == Type::CONTROL )
       // Warm up next pile of heuristic bits
       needed_for_next_call(block, n, next_call);
     // Children of projections are now all ready
     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
       Node* m = n->fast_out(j); // Get user
       if(get_block_for_node(m) != block) {
         continue;
       }
       if( m->is_Phi() ) continue;
       int m_cnt = ready_cnt.at(m->_idx)-1;
       ready_cnt.at_put(m->_idx, m_cnt);
       if( m_cnt == 0 )
         worklist.push(m);
     }
   }
   // Act as if the call defines the Frame Pointer.
   // Certainly the FP is alive and well after the call.
   regs.Insert(_matcher.c_frame_pointer());
   // Set all registers killed and not already defined by the call.
   uint r_cnt = mcall->tf()->range()->cnt();
   int op = mcall->ideal_Opcode();
   MachProjNode *proj = new (C) MachProjNode( mcall, r_cnt+1, RegMask::Empty, MachProjNode::fat_proj );
   map_node_to_block(proj, block);
   block->insert_node(proj, node_cnt++);
   // Select the right register save policy.
   const char * save_policy;
   switch (op) {
     case Op_CallRuntime:
     case Op_CallLeaf:
     case Op_CallLeafNoFP:
       // Calling C code so use C calling convention
       save_policy = _matcher._c_reg_save_policy;
       break;
     case Op_CallStaticJava:
     case Op_CallDynamicJava:
       // Calling Java code so use Java calling convention
       save_policy = _matcher._register_save_policy;
       break;
     default:
       ShouldNotReachHere();
   }
   // When using CallRuntime mark SOE registers as killed by the call
   // so values that could show up in the RegisterMap aren't live in a
   // callee saved register since the register wouldn't know where to
   // find them.  CallLeaf and CallLeafNoFP are ok because they can't
   // have debug info on them.  Strictly speaking this only needs to be
   // done for oops since idealreg2debugmask takes care of debug info
   // references but there no way to handle oops differently than other
   // pointers as far as the kill mask goes.
   bool exclude_soe = op == Op_CallRuntime;
   // If the call is a MethodHandle invoke, we need to exclude the
   // register which is used to save the SP value over MH invokes from
   // the mask.  Otherwise this register could be used for
   // deoptimization information.
   if (op == Op_CallStaticJava) {
     MachCallStaticJavaNode* mcallstaticjava = (MachCallStaticJavaNode*) mcall;
     if (mcallstaticjava->_method_handle_invoke)
       proj->_rout.OR(Matcher::method_handle_invoke_SP_save_mask());
   }
   add_call_kills(proj, regs, save_policy, exclude_soe);
   return node_cnt;
 }
 //------------------------------schedule_local---------------------------------
 // Topological sort within a block.  Someday become a real scheduler.
 bool PhaseCFG::schedule_local(Block* block, GrowableArray<int>& ready_cnt, VectorSet& next_call) {
   // Already "sorted" are the block start Node (as the first entry), and
   // the block-ending Node and any trailing control projections.  We leave
   // these alone.  PhiNodes and ParmNodes are made to follow the block start
   // Node.  Everything else gets topo-sorted.
 #ifndef PRODUCT
     if (trace_opto_pipelining()) {
       tty->print_cr("# --- schedule_local B%d, before: ---", block->_pre_order);
       for (uint i = 0;i < block->number_of_nodes(); i++) {
         tty->print("# ");
         block->get_node(i)->fast_dump();
       }
       tty->print_cr("#");
     }
 #endif
   // RootNode is already sorted
   if (block->number_of_nodes() == 1) {
     return true;
   }
   // Move PhiNodes and ParmNodes from 1 to cnt up to the start
   uint node_cnt = block->end_idx();
   uint phi_cnt = 1;
   uint i;
   for( i = 1; i<node_cnt; i++ ) { // Scan for Phi
     Node *n = block->get_node(i);
     if( n->is_Phi() ||          // Found a PhiNode or ParmNode
         (n->is_Proj()  && n->in(0) == block->head()) ) {
       // Move guy at 'phi_cnt' to the end; makes a hole at phi_cnt
       block->map_node(block->get_node(phi_cnt), i);
       block->map_node(n, phi_cnt++);  // swap Phi/Parm up front
     } else {                    // All others
       // Count block-local inputs to 'n'
       uint cnt = n->len();      // Input count
       uint local = 0;
       for( uint j=0; j<cnt; j++ ) {
         Node *m = n->in(j);
         if( m && get_block_for_node(m) == block && !m->is_top() )
           local++;              // One more block-local input
       }
       ready_cnt.at_put(n->_idx, local); // Count em up
 #ifdef ASSERT
       if( UseConcMarkSweepGC || UseG1GC ) {
         if( n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_StoreCM ) {
           // Check the precedence edges
           for (uint prec = n->req(); prec < n->len(); prec++) {
             Node* oop_store = n->in(prec);
             if (oop_store != NULL) {
               assert(get_block_for_node(oop_store)->_dom_depth <= block->_dom_depth, "oop_store must dominate card-mark");
             }
           }
         }
       }
 #endif
       // A few node types require changing a required edge to a precedence edge
       // before allocation.
       if( n->is_Mach() && n->req() > TypeFunc::Parms &&
           (n->as_Mach()->ideal_Opcode() == Op_MemBarAcquire ||
            n->as_Mach()->ideal_Opcode() == Op_MemBarVolatile) ) {
         // MemBarAcquire could be created without Precedent edge.
         // del_req() replaces the specified edge with the last input edge
         // and then removes the last edge. If the specified edge > number of
         // edges the last edge will be moved outside of the input edges array
         // and the edge will be lost. This is why this code should be
         // executed only when Precedent (== TypeFunc::Parms) edge is present.
         Node *x = n->in(TypeFunc::Parms);
         n->del_req(TypeFunc::Parms);
         n->add_prec(x);
       }
     }
   }
   for(uint i2=i; i2< block->number_of_nodes(); i2++ ) // Trailing guys get zapped count
     ready_cnt.at_put(block->get_node(i2)->_idx, 0);
   // All the prescheduled guys do not hold back internal nodes
   uint i3;
   for(i3 = 0; i3<phi_cnt; i3++ ) {  // For all pre-scheduled
     Node *n = block->get_node(i3);       // Get pre-scheduled
     for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
       Node* m = n->fast_out(j);
       if (get_block_for_node(m) == block) { // Local-block user
         int m_cnt = ready_cnt.at(m->_idx)-1;
         ready_cnt.at_put(m->_idx, m_cnt);   // Fix ready count
       }
     }
   }
   Node_List delay;
   // Make a worklist
   Node_List worklist;
   for(uint i4=i3; i4<node_cnt; i4++ ) {    // Put ready guys on worklist
     Node *m = block->get_node(i4);
     if( !ready_cnt.at(m->_idx) ) {   // Zero ready count?
       if (m->is_iteratively_computed()) {
         // Push induction variable increments last to allow other uses
         // of the phi to be scheduled first. The select() method breaks
         // ties in scheduling by worklist order.
         delay.push(m);
       } else if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CreateEx) {
         // Force the CreateEx to the top of the list so it's processed
         // first and ends up at the start of the block.
         worklist.insert(0, m);
       } else {
         worklist.push(m);         // Then on to worklist!
       }
     }
   }
   while (delay.size()) {
     Node* d = delay.pop();
     worklist.push(d);
   }
   // Warm up the 'next_call' heuristic bits
   needed_for_next_call(block, block->head(), next_call);
 #ifndef PRODUCT
     if (trace_opto_pipelining()) {
       for (uint j=0; j< block->number_of_nodes(); j++) {
         Node     *n = block->get_node(j);
         int     idx = n->_idx;
         tty->print("#   ready cnt:%3d  ", ready_cnt.at(idx));
         tty->print("latency:%3d  ", get_latency_for_node(n));
         tty->print("%4d: %s\n", idx, n->Name());
       }
     }
 #endif
   uint max_idx = (uint)ready_cnt.length();
   // Pull from worklist and schedule
   while( worklist.size() ) {    // Worklist is not ready
 #ifndef PRODUCT
     if (trace_opto_pipelining()) {
       tty->print("#   ready list:");
       for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
         Node *n = worklist[i];      // Get Node on worklist
         tty->print(" %d", n->_idx);
       }
       tty->cr();
     }
 #endif
     // Select and pop a ready guy from worklist
     Node* n = select(block, worklist, ready_cnt, next_call, phi_cnt);
     block->map_node(n, phi_cnt++);    // Schedule him next
 #ifndef PRODUCT
     if (trace_opto_pipelining()) {
       tty->print("#    select %d: %s", n->_idx, n->Name());
       tty->print(", latency:%d", get_latency_for_node(n));
       n->dump();
       if (Verbose) {
         tty->print("#   ready list:");
         for( uint i=0; i<worklist.size(); i++ ) { // Inspect entire worklist
           Node *n = worklist[i];      // Get Node on worklist
           tty->print(" %d", n->_idx);
         }
         tty->cr();
       }
     }
 #endif
     if( n->is_MachCall() ) {
       MachCallNode *mcall = n->as_MachCall();
       phi_cnt = sched_call(block, phi_cnt, worklist, ready_cnt, mcall, next_call);
       continue;
     }
     if (n->is_Mach() && n->as_Mach()->has_call()) {
       RegMask regs;
       regs.Insert(_matcher.c_frame_pointer());
       regs.OR(n->out_RegMask());
       MachProjNode *proj = new (C) MachProjNode( n, 1, RegMask::Empty, MachProjNode::fat_proj );
       map_node_to_block(proj, block);
       block->insert_node(proj, phi_cnt++);
       add_call_kills(proj, regs, _matcher._c_reg_save_policy, false);
     }
     // Children are now all ready
     for (DUIterator_Fast i5max, i5 = n->fast_outs(i5max); i5 < i5max; i5++) {
       Node* m = n->fast_out(i5); // Get user
       if (get_block_for_node(m) != block) {
         continue;
       }
       if( m->is_Phi() ) continue;
       if (m->_idx >= max_idx) { // new node, skip it
         assert(m->is_MachProj() && n->is_Mach() && n->as_Mach()->has_call(), "unexpected node types");
         continue;
       }
       int m_cnt = ready_cnt.at(m->_idx)-1;
       ready_cnt.at_put(m->_idx, m_cnt);
       if( m_cnt == 0 )
         worklist.push(m);
     }
   }
   if( phi_cnt != block->end_idx() ) {
     // did not schedule all.  Retry, Bailout, or Die
     if (C->subsume_loads() == true && !C->failing()) {
       // Retry with subsume_loads == false
       // If this is the first failure, the sentinel string will "stick"
       // to the Compile object, and the C2Compiler will see it and retry.
       C->record_failure(C2Compiler::retry_no_subsuming_loads());
     }
     // assert( phi_cnt == end_idx(), "did not schedule all" );
     return false;
   }
 #ifndef PRODUCT
   if (trace_opto_pipelining()) {
     tty->print_cr("#");
     tty->print_cr("# after schedule_local");
     for (uint i = 0;i < block->number_of_nodes();i++) {
       tty->print("# ");
       block->get_node(i)->fast_dump();
     }
     tty->cr();
   }
 #endif
   return true;
 }
 //--------------------------catch_cleanup_fix_all_inputs-----------------------
 static void catch_cleanup_fix_all_inputs(Node *use, Node *old_def, Node *new_def) {
   for (uint l = 0; l < use->len(); l++) {
     if (use->in(l) == old_def) {
       if (l < use->req()) {
         use->set_req(l, new_def);
       } else {
         use->rm_prec(l);
         use->add_prec(new_def);
         l--;
       }
     }
   }
 }
 //------------------------------catch_cleanup_find_cloned_def------------------
 Node* PhaseCFG::catch_cleanup_find_cloned_def(Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
   assert( use_blk != def_blk, "Inter-block cleanup only");
   // The use is some block below the Catch.  Find and return the clone of the def
   // that dominates the use. If there is no clone in a dominating block, then
   // create a phi for the def in a dominating block.
   // Find which successor block dominates this use.  The successor
   // blocks must all be single-entry (from the Catch only; I will have
   // split blocks to make this so), hence they all dominate.
   while( use_blk->_dom_depth > def_blk->_dom_depth+1 )
     use_blk = use_blk->_idom;
   // Find the successor
   Node *fixup = NULL;
   uint j;
   for( j = 0; j < def_blk->_num_succs; j++ )
     if( use_blk == def_blk->_succs[j] )
       break;
   if( j == def_blk->_num_succs ) {
     // Block at same level in dom-tree is not a successor.  It needs a
     // PhiNode, the PhiNode uses from the def and IT's uses need fixup.
     Node_Array inputs = new Node_List(Thread::current()->resource_area());
     for(uint k = 1; k < use_blk->num_preds(); k++) {
       Block* block = get_block_for_node(use_blk->pred(k));
       inputs.map(k, catch_cleanup_find_cloned_def(block, def, def_blk, n_clone_idx));
     }
     // Check to see if the use_blk already has an identical phi inserted.
     // If it exists, it will be at the first position since all uses of a
     // def are processed together.
     Node *phi = use_blk->get_node(1);
     if( phi->is_Phi() ) {
       fixup = phi;
       for (uint k = 1; k < use_blk->num_preds(); k++) {
         if (phi->in(k) != inputs[k]) {
           // Not a match
           fixup = NULL;
           break;
         }
       }
     }
     // If an existing PhiNode was not found, make a new one.
     if (fixup == NULL) {
       Node *new_phi = PhiNode::make(use_blk->head(), def);
       use_blk->insert_node(new_phi, 1);
       map_node_to_block(new_phi, use_blk);
       for (uint k = 1; k < use_blk->num_preds(); k++) {
         new_phi->set_req(k, inputs[k]);
       }
       fixup = new_phi;
     }
   } else {
     // Found the use just below the Catch.  Make it use the clone.
     fixup = use_blk->get_node(n_clone_idx);
   }
   return fixup;
 }
 //--------------------------catch_cleanup_intra_block--------------------------
 // Fix all input edges in use that reference "def".  The use is in the same
 // block as the def and both have been cloned in each successor block.
 static void catch_cleanup_intra_block(Node *use, Node *def, Block *blk, int beg, int n_clone_idx) {
   // Both the use and def have been cloned. For each successor block,
   // get the clone of the use, and make its input the clone of the def
   // found in that block.
   uint use_idx = blk->find_node(use);
   uint offset_idx = use_idx - beg;
   for( uint k = 0; k < blk->_num_succs; k++ ) {
     // Get clone in each successor block
     Block *sb = blk->_succs[k];
     Node *clone = sb->get_node(offset_idx+1);
     assert( clone->Opcode() == use->Opcode(), "" );
     // Make use-clone reference the def-clone
     catch_cleanup_fix_all_inputs(clone, def, sb->get_node(n_clone_idx));
   }
 }
 //------------------------------catch_cleanup_inter_block---------------------
 // Fix all input edges in use that reference "def".  The use is in a different
 // block than the def.
 void PhaseCFG::catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, int n_clone_idx) {
   if( !use_blk ) return;        // Can happen if the use is a precedence edge
   Node *new_def = catch_cleanup_find_cloned_def(use_blk, def, def_blk, n_clone_idx);
   catch_cleanup_fix_all_inputs(use, def, new_def);
 }
 //------------------------------call_catch_cleanup-----------------------------
 // If we inserted any instructions between a Call and his CatchNode,
 // clone the instructions on all paths below the Catch.
 void PhaseCFG::call_catch_cleanup(Block* block) {
   // End of region to clone
   uint end = block->end_idx();
   if( !block->get_node(end)->is_Catch() ) return;
   // Start of region to clone
   uint beg = end;
   while(!block->get_node(beg-1)->is_MachProj() ||
         !block->get_node(beg-1)->in(0)->is_MachCall() ) {
     beg--;
     assert(beg > 0,"Catch cleanup walking beyond block boundary");
   }
   // Range of inserted instructions is [beg, end)
   if( beg == end ) return;
   // Clone along all Catch output paths.  Clone area between the 'beg' and
   // 'end' indices.
   for( uint i = 0; i < block->_num_succs; i++ ) {
     Block *sb = block->_succs[i];
     // Clone the entire area; ignoring the edge fixup for now.
     for( uint j = end; j > beg; j-- ) {
       // It is safe here to clone a node with anti_dependence
       // since clones dominate on each path.
       Node *clone = block->get_node(j-1)->clone();
       sb->insert_node(clone, 1);
       map_node_to_block(clone, sb);
     }
   }
   // Fixup edges.  Check the def-use info per cloned Node
   for(uint i2 = beg; i2 < end; i2++ ) {
     uint n_clone_idx = i2-beg+1; // Index of clone of n in each successor block
     Node *n = block->get_node(i2);        // Node that got cloned
     // Need DU safe iterator because of edge manipulation in calls.
     Unique_Node_List *out = new Unique_Node_List(Thread::current()->resource_area());
     for (DUIterator_Fast j1max, j1 = n->fast_outs(j1max); j1 < j1max; j1++) {
       out->push(n->fast_out(j1));
     }
     uint max = out->size();
     for (uint j = 0; j < max; j++) {// For all users
       Node *use = out->pop();
       Block *buse = get_block_for_node(use);
       if( use->is_Phi() ) {
         for( uint k = 1; k < use->req(); k++ )
           if( use->in(k) == n ) {
             Block* b = get_block_for_node(buse->pred(k));
             Node *fixup = catch_cleanup_find_cloned_def(b, n, block, n_clone_idx);
             use->set_req(k, fixup);
           }
       } else {
         if (block == buse) {
           catch_cleanup_intra_block(use, n, block, beg, n_clone_idx);
         } else {
           catch_cleanup_inter_block(use, buse, n, block, n_clone_idx);
         }
       }
     } // End for all users
   } // End of for all Nodes in cloned area
   // Remove the now-dead cloned ops
   for(uint i3 = beg; i3 < end; i3++ ) {
     block->get_node(beg)->disconnect_inputs(NULL, C);
     block->remove_node(beg);
   }
   // If the successor blocks have a CreateEx node, move it back to the top
   for(uint i4 = 0; i4 < block->_num_succs; i4++ ) {
     Block *sb = block->_succs[i4];
     uint new_cnt = end - beg;
     // Remove any newly created, but dead, nodes.
     for( uint j = new_cnt; j > 0; j-- ) {
       Node *n = sb->get_node(j);
       if (n->outcnt() == 0 &&
           (!n->is_Proj() || n->as_Proj()->in(0)->outcnt() == 1) ){
         n->disconnect_inputs(NULL, C);
         sb->remove_node(j);
         new_cnt--;
       }
     }
     // If any newly created nodes remain, move the CreateEx node to the top
     if (new_cnt > 0) {
       Node *cex = sb->get_node(1+new_cnt);
       if( cex->is_Mach() && cex->as_Mach()->ideal_Opcode() == Op_CreateEx ) {
         sb->remove_node(1+new_cnt);
         sb->insert_node(cex, 1);
       }
     }
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/opto/lcm.cpp@c1c199dde5c9 (annotated)

src/share/vm/opto/lcm.cpp