| /* |
| * Copyright (c) 2002, 2013, 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 "compiler/oopMap.hpp" |
| #include "opto/addnode.hpp" |
| #include "opto/callnode.hpp" |
| #include "opto/compile.hpp" |
| #include "opto/machnode.hpp" |
| #include "opto/matcher.hpp" |
| #include "opto/phase.hpp" |
| #include "opto/regalloc.hpp" |
| #include "opto/rootnode.hpp" |
| #ifdef TARGET_ARCH_x86 |
| # include "vmreg_x86.inline.hpp" |
| #endif |
| #ifdef TARGET_ARCH_sparc |
| # include "vmreg_sparc.inline.hpp" |
| #endif |
| #ifdef TARGET_ARCH_zero |
| # include "vmreg_zero.inline.hpp" |
| #endif |
| #ifdef TARGET_ARCH_arm |
| # include "vmreg_arm.inline.hpp" |
| #endif |
| #ifdef TARGET_ARCH_ppc |
| # include "vmreg_ppc.inline.hpp" |
| #endif |
| |
| // The functions in this file builds OopMaps after all scheduling is done. |
| // |
| // OopMaps contain a list of all registers and stack-slots containing oops (so |
| // they can be updated by GC). OopMaps also contain a list of derived-pointer |
| // base-pointer pairs. When the base is moved, the derived pointer moves to |
| // follow it. Finally, any registers holding callee-save values are also |
| // recorded. These might contain oops, but only the caller knows. |
| // |
| // BuildOopMaps implements a simple forward reaching-defs solution. At each |
| // GC point we'll have the reaching-def Nodes. If the reaching Nodes are |
| // typed as pointers (no offset), then they are oops. Pointers+offsets are |
| // derived pointers, and bases can be found from them. Finally, we'll also |
| // track reaching callee-save values. Note that a copy of a callee-save value |
| // "kills" it's source, so that only 1 copy of a callee-save value is alive at |
| // a time. |
| // |
| // We run a simple bitvector liveness pass to help trim out dead oops. Due to |
| // irreducible loops, we can have a reaching def of an oop that only reaches |
| // along one path and no way to know if it's valid or not on the other path. |
| // The bitvectors are quite dense and the liveness pass is fast. |
| // |
| // At GC points, we consult this information to build OopMaps. All reaching |
| // defs typed as oops are added to the OopMap. Only 1 instance of a |
| // callee-save register can be recorded. For derived pointers, we'll have to |
| // find and record the register holding the base. |
| // |
| // The reaching def's is a simple 1-pass worklist approach. I tried a clever |
| // breadth-first approach but it was worse (showed O(n^2) in the |
| // pick-next-block code). |
| // |
| // The relevant data is kept in a struct of arrays (it could just as well be |
| // an array of structs, but the struct-of-arrays is generally a little more |
| // efficient). The arrays are indexed by register number (including |
| // stack-slots as registers) and so is bounded by 200 to 300 elements in |
| // practice. One array will map to a reaching def Node (or NULL for |
| // conflict/dead). The other array will map to a callee-saved register or |
| // OptoReg::Bad for not-callee-saved. |
| |
| |
| // Structure to pass around |
| struct OopFlow : public ResourceObj { |
| short *_callees; // Array mapping register to callee-saved |
| Node **_defs; // array mapping register to reaching def |
| // or NULL if dead/conflict |
| // OopFlow structs, when not being actively modified, describe the _end_ of |
| // this block. |
| Block *_b; // Block for this struct |
| OopFlow *_next; // Next free OopFlow |
| // or NULL if dead/conflict |
| Compile* C; |
| |
| OopFlow( short *callees, Node **defs, Compile* c ) : _callees(callees), _defs(defs), |
| _b(NULL), _next(NULL), C(c) { } |
| |
| // Given reaching-defs for this block start, compute it for this block end |
| void compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ); |
| |
| // Merge these two OopFlows into the 'this' pointer. |
| void merge( OopFlow *flow, int max_reg ); |
| |
| // Copy a 'flow' over an existing flow |
| void clone( OopFlow *flow, int max_size); |
| |
| // Make a new OopFlow from scratch |
| static OopFlow *make( Arena *A, int max_size, Compile* C ); |
| |
| // Build an oopmap from the current flow info |
| OopMap *build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ); |
| }; |
| |
| // Given reaching-defs for this block start, compute it for this block end |
| void OopFlow::compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ) { |
| |
| for( uint i=0; i<_b->number_of_nodes(); i++ ) { |
| Node *n = _b->get_node(i); |
| |
| if( n->jvms() ) { // Build an OopMap here? |
| JVMState *jvms = n->jvms(); |
| // no map needed for leaf calls |
| if( n->is_MachSafePoint() && !n->is_MachCallLeaf() ) { |
| int *live = (int*) (*safehash)[n]; |
| assert( live, "must find live" ); |
| n->as_MachSafePoint()->set_oop_map( build_oop_map(n,max_reg,regalloc, live) ); |
| } |
| } |
| |
| // Assign new reaching def's. |
| // Note that I padded the _defs and _callees arrays so it's legal |
| // to index at _defs[OptoReg::Bad]. |
| OptoReg::Name first = regalloc->get_reg_first(n); |
| OptoReg::Name second = regalloc->get_reg_second(n); |
| _defs[first] = n; |
| _defs[second] = n; |
| |
| // Pass callee-save info around copies |
| int idx = n->is_Copy(); |
| if( idx ) { // Copies move callee-save info |
| OptoReg::Name old_first = regalloc->get_reg_first(n->in(idx)); |
| OptoReg::Name old_second = regalloc->get_reg_second(n->in(idx)); |
| int tmp_first = _callees[old_first]; |
| int tmp_second = _callees[old_second]; |
| _callees[old_first] = OptoReg::Bad; // callee-save is moved, dead in old location |
| _callees[old_second] = OptoReg::Bad; |
| _callees[first] = tmp_first; |
| _callees[second] = tmp_second; |
| } else if( n->is_Phi() ) { // Phis do not mod callee-saves |
| assert( _callees[first] == _callees[regalloc->get_reg_first(n->in(1))], "" ); |
| assert( _callees[second] == _callees[regalloc->get_reg_second(n->in(1))], "" ); |
| assert( _callees[first] == _callees[regalloc->get_reg_first(n->in(n->req()-1))], "" ); |
| assert( _callees[second] == _callees[regalloc->get_reg_second(n->in(n->req()-1))], "" ); |
| } else { |
| _callees[first] = OptoReg::Bad; // No longer holding a callee-save value |
| _callees[second] = OptoReg::Bad; |
| |
| // Find base case for callee saves |
| if( n->is_Proj() && n->in(0)->is_Start() ) { |
| if( OptoReg::is_reg(first) && |
| regalloc->_matcher.is_save_on_entry(first) ) |
| _callees[first] = first; |
| if( OptoReg::is_reg(second) && |
| regalloc->_matcher.is_save_on_entry(second) ) |
| _callees[second] = second; |
| } |
| } |
| } |
| } |
| |
| // Merge the given flow into the 'this' flow |
| void OopFlow::merge( OopFlow *flow, int max_reg ) { |
| assert( _b == NULL, "merging into a happy flow" ); |
| assert( flow->_b, "this flow is still alive" ); |
| assert( flow != this, "no self flow" ); |
| |
| // Do the merge. If there are any differences, drop to 'bottom' which |
| // is OptoReg::Bad or NULL depending. |
| for( int i=0; i<max_reg; i++ ) { |
| // Merge the callee-save's |
| if( _callees[i] != flow->_callees[i] ) |
| _callees[i] = OptoReg::Bad; |
| // Merge the reaching defs |
| if( _defs[i] != flow->_defs[i] ) |
| _defs[i] = NULL; |
| } |
| |
| } |
| |
| void OopFlow::clone( OopFlow *flow, int max_size ) { |
| _b = flow->_b; |
| memcpy( _callees, flow->_callees, sizeof(short)*max_size); |
| memcpy( _defs , flow->_defs , sizeof(Node*)*max_size); |
| } |
| |
| OopFlow *OopFlow::make( Arena *A, int max_size, Compile* C ) { |
| short *callees = NEW_ARENA_ARRAY(A,short,max_size+1); |
| Node **defs = NEW_ARENA_ARRAY(A,Node*,max_size+1); |
| debug_only( memset(defs,0,(max_size+1)*sizeof(Node*)) ); |
| OopFlow *flow = new (A) OopFlow(callees+1, defs+1, C); |
| assert( &flow->_callees[OptoReg::Bad] == callees, "Ok to index at OptoReg::Bad" ); |
| assert( &flow->_defs [OptoReg::Bad] == defs , "Ok to index at OptoReg::Bad" ); |
| return flow; |
| } |
| |
| static int get_live_bit( int *live, int reg ) { |
| return live[reg>>LogBitsPerInt] & (1<<(reg&(BitsPerInt-1))); } |
| static void set_live_bit( int *live, int reg ) { |
| live[reg>>LogBitsPerInt] |= (1<<(reg&(BitsPerInt-1))); } |
| static void clr_live_bit( int *live, int reg ) { |
| live[reg>>LogBitsPerInt] &= ~(1<<(reg&(BitsPerInt-1))); } |
| |
| // Build an oopmap from the current flow info |
| OopMap *OopFlow::build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ) { |
| int framesize = regalloc->_framesize; |
| int max_inarg_slot = OptoReg::reg2stack(regalloc->_matcher._new_SP); |
| debug_only( char *dup_check = NEW_RESOURCE_ARRAY(char,OptoReg::stack0()); |
| memset(dup_check,0,OptoReg::stack0()) ); |
| |
| OopMap *omap = new OopMap( framesize, max_inarg_slot ); |
| MachCallNode *mcall = n->is_MachCall() ? n->as_MachCall() : NULL; |
| JVMState* jvms = n->jvms(); |
| |
| // For all registers do... |
| for( int reg=0; reg<max_reg; reg++ ) { |
| if( get_live_bit(live,reg) == 0 ) |
| continue; // Ignore if not live |
| |
| // %%% C2 can use 2 OptoRegs when the physical register is only one 64bit |
| // register in that case we'll get an non-concrete register for the second |
| // half. We only need to tell the map the register once! |
| // |
| // However for the moment we disable this change and leave things as they |
| // were. |
| |
| VMReg r = OptoReg::as_VMReg(OptoReg::Name(reg), framesize, max_inarg_slot); |
| |
| if (false && r->is_reg() && !r->is_concrete()) { |
| continue; |
| } |
| |
| // See if dead (no reaching def). |
| Node *def = _defs[reg]; // Get reaching def |
| assert( def, "since live better have reaching def" ); |
| |
| // Classify the reaching def as oop, derived, callee-save, dead, or other |
| const Type *t = def->bottom_type(); |
| if( t->isa_oop_ptr() ) { // Oop or derived? |
| assert( !OptoReg::is_valid(_callees[reg]), "oop can't be callee save" ); |
| #ifdef _LP64 |
| // 64-bit pointers record oop-ishness on 2 aligned adjacent registers. |
| // Make sure both are record from the same reaching def, but do not |
| // put both into the oopmap. |
| if( (reg&1) == 1 ) { // High half of oop-pair? |
| assert( _defs[reg-1] == _defs[reg], "both halves from same reaching def" ); |
| continue; // Do not record high parts in oopmap |
| } |
| #endif |
| |
| // Check for a legal reg name in the oopMap and bailout if it is not. |
| if (!omap->legal_vm_reg_name(r)) { |
| regalloc->C->record_method_not_compilable("illegal oopMap register name"); |
| continue; |
| } |
| if( t->is_ptr()->_offset == 0 ) { // Not derived? |
| if( mcall ) { |
| // Outgoing argument GC mask responsibility belongs to the callee, |
| // not the caller. Inspect the inputs to the call, to see if |
| // this live-range is one of them. |
| uint cnt = mcall->tf()->domain()->cnt(); |
| uint j; |
| for( j = TypeFunc::Parms; j < cnt; j++) |
| if( mcall->in(j) == def ) |
| break; // reaching def is an argument oop |
| if( j < cnt ) // arg oops dont go in GC map |
| continue; // Continue on to the next register |
| } |
| omap->set_oop(r); |
| } else { // Else it's derived. |
| // Find the base of the derived value. |
| uint i; |
| // Fast, common case, scan |
| for( i = jvms->oopoff(); i < n->req(); i+=2 ) |
| if( n->in(i) == def ) break; // Common case |
| if( i == n->req() ) { // Missed, try a more generous scan |
| // Scan again, but this time peek through copies |
| for( i = jvms->oopoff(); i < n->req(); i+=2 ) { |
| Node *m = n->in(i); // Get initial derived value |
| while( 1 ) { |
| Node *d = def; // Get initial reaching def |
| while( 1 ) { // Follow copies of reaching def to end |
| if( m == d ) goto found; // breaks 3 loops |
| int idx = d->is_Copy(); |
| if( !idx ) break; |
| d = d->in(idx); // Link through copy |
| } |
| int idx = m->is_Copy(); |
| if( !idx ) break; |
| m = m->in(idx); |
| } |
| } |
| guarantee( 0, "must find derived/base pair" ); |
| } |
| found: ; |
| Node *base = n->in(i+1); // Base is other half of pair |
| int breg = regalloc->get_reg_first(base); |
| VMReg b = OptoReg::as_VMReg(OptoReg::Name(breg), framesize, max_inarg_slot); |
| |
| // I record liveness at safepoints BEFORE I make the inputs |
| // live. This is because argument oops are NOT live at a |
| // safepoint (or at least they cannot appear in the oopmap). |
| // Thus bases of base/derived pairs might not be in the |
| // liveness data but they need to appear in the oopmap. |
| if( get_live_bit(live,breg) == 0 ) {// Not live? |
| // Flag it, so next derived pointer won't re-insert into oopmap |
| set_live_bit(live,breg); |
| // Already missed our turn? |
| if( breg < reg ) { |
| if (b->is_stack() || b->is_concrete() || true ) { |
| omap->set_oop( b); |
| } |
| } |
| } |
| if (b->is_stack() || b->is_concrete() || true ) { |
| omap->set_derived_oop( r, b); |
| } |
| } |
| |
| } else if( t->isa_narrowoop() ) { |
| assert( !OptoReg::is_valid(_callees[reg]), "oop can't be callee save" ); |
| // Check for a legal reg name in the oopMap and bailout if it is not. |
| if (!omap->legal_vm_reg_name(r)) { |
| regalloc->C->record_method_not_compilable("illegal oopMap register name"); |
| continue; |
| } |
| if( mcall ) { |
| // Outgoing argument GC mask responsibility belongs to the callee, |
| // not the caller. Inspect the inputs to the call, to see if |
| // this live-range is one of them. |
| uint cnt = mcall->tf()->domain()->cnt(); |
| uint j; |
| for( j = TypeFunc::Parms; j < cnt; j++) |
| if( mcall->in(j) == def ) |
| break; // reaching def is an argument oop |
| if( j < cnt ) // arg oops dont go in GC map |
| continue; // Continue on to the next register |
| } |
| omap->set_narrowoop(r); |
| } else if( OptoReg::is_valid(_callees[reg])) { // callee-save? |
| // It's a callee-save value |
| assert( dup_check[_callees[reg]]==0, "trying to callee save same reg twice" ); |
| debug_only( dup_check[_callees[reg]]=1; ) |
| VMReg callee = OptoReg::as_VMReg(OptoReg::Name(_callees[reg])); |
| if ( callee->is_concrete() || true ) { |
| omap->set_callee_saved( r, callee); |
| } |
| |
| } else { |
| // Other - some reaching non-oop value |
| omap->set_value( r); |
| #ifdef ASSERT |
| if( t->isa_rawptr() && C->cfg()->_raw_oops.member(def) ) { |
| def->dump(); |
| n->dump(); |
| assert(false, "there should be a oop in OopMap instead of a live raw oop at safepoint"); |
| } |
| #endif |
| } |
| |
| } |
| |
| #ifdef ASSERT |
| /* Nice, Intel-only assert |
| int cnt_callee_saves=0; |
| int reg2 = 0; |
| while (OptoReg::is_reg(reg2)) { |
| if( dup_check[reg2] != 0) cnt_callee_saves++; |
| assert( cnt_callee_saves==3 || cnt_callee_saves==5, "missed some callee-save" ); |
| reg2++; |
| } |
| */ |
| #endif |
| |
| #ifdef ASSERT |
| for( OopMapStream oms1(omap, OopMapValue::derived_oop_value); !oms1.is_done(); oms1.next()) { |
| OopMapValue omv1 = oms1.current(); |
| bool found = false; |
| for( OopMapStream oms2(omap,OopMapValue::oop_value); !oms2.is_done(); oms2.next()) { |
| if( omv1.content_reg() == oms2.current().reg() ) { |
| found = true; |
| break; |
| } |
| } |
| assert( found, "derived with no base in oopmap" ); |
| } |
| #endif |
| |
| return omap; |
| } |
| |
| // Compute backwards liveness on registers |
| static void do_liveness(PhaseRegAlloc* regalloc, PhaseCFG* cfg, Block_List* worklist, int max_reg_ints, Arena* A, Dict* safehash) { |
| int* live = NEW_ARENA_ARRAY(A, int, (cfg->number_of_blocks() + 1) * max_reg_ints); |
| int* tmp_live = &live[cfg->number_of_blocks() * max_reg_ints]; |
| Node* root = cfg->get_root_node(); |
| // On CISC platforms, get the node representing the stack pointer that regalloc |
| // used for spills |
| Node *fp = NodeSentinel; |
| if (UseCISCSpill && root->req() > 1) { |
| fp = root->in(1)->in(TypeFunc::FramePtr); |
| } |
| memset(live, 0, cfg->number_of_blocks() * (max_reg_ints << LogBytesPerInt)); |
| // Push preds onto worklist |
| for (uint i = 1; i < root->req(); i++) { |
| Block* block = cfg->get_block_for_node(root->in(i)); |
| worklist->push(block); |
| } |
| |
| // ZKM.jar includes tiny infinite loops which are unreached from below. |
| // If we missed any blocks, we'll retry here after pushing all missed |
| // blocks on the worklist. Normally this outer loop never trips more |
| // than once. |
| while (1) { |
| |
| while( worklist->size() ) { // Standard worklist algorithm |
| Block *b = worklist->rpop(); |
| |
| // Copy first successor into my tmp_live space |
| int s0num = b->_succs[0]->_pre_order; |
| int *t = &live[s0num*max_reg_ints]; |
| for( int i=0; i<max_reg_ints; i++ ) |
| tmp_live[i] = t[i]; |
| |
| // OR in the remaining live registers |
| for( uint j=1; j<b->_num_succs; j++ ) { |
| uint sjnum = b->_succs[j]->_pre_order; |
| int *t = &live[sjnum*max_reg_ints]; |
| for( int i=0; i<max_reg_ints; i++ ) |
| tmp_live[i] |= t[i]; |
| } |
| |
| // Now walk tmp_live up the block backwards, computing live |
| for( int k=b->number_of_nodes()-1; k>=0; k-- ) { |
| Node *n = b->get_node(k); |
| // KILL def'd bits |
| int first = regalloc->get_reg_first(n); |
| int second = regalloc->get_reg_second(n); |
| if( OptoReg::is_valid(first) ) clr_live_bit(tmp_live,first); |
| if( OptoReg::is_valid(second) ) clr_live_bit(tmp_live,second); |
| |
| MachNode *m = n->is_Mach() ? n->as_Mach() : NULL; |
| |
| // Check if m is potentially a CISC alternate instruction (i.e, possibly |
| // synthesized by RegAlloc from a conventional instruction and a |
| // spilled input) |
| bool is_cisc_alternate = false; |
| if (UseCISCSpill && m) { |
| is_cisc_alternate = m->is_cisc_alternate(); |
| } |
| |
| // GEN use'd bits |
| for( uint l=1; l<n->req(); l++ ) { |
| Node *def = n->in(l); |
| assert(def != 0, "input edge required"); |
| int first = regalloc->get_reg_first(def); |
| int second = regalloc->get_reg_second(def); |
| if( OptoReg::is_valid(first) ) set_live_bit(tmp_live,first); |
| if( OptoReg::is_valid(second) ) set_live_bit(tmp_live,second); |
| // If we use the stack pointer in a cisc-alternative instruction, |
| // check for use as a memory operand. Then reconstruct the RegName |
| // for this stack location, and set the appropriate bit in the |
| // live vector 4987749. |
| if (is_cisc_alternate && def == fp) { |
| const TypePtr *adr_type = NULL; |
| intptr_t offset; |
| const Node* base = m->get_base_and_disp(offset, adr_type); |
| if (base == NodeSentinel) { |
| // Machnode has multiple memory inputs. We are unable to reason |
| // with these, but are presuming (with trepidation) that not any of |
| // them are oops. This can be fixed by making get_base_and_disp() |
| // look at a specific input instead of all inputs. |
| assert(!def->bottom_type()->isa_oop_ptr(), "expecting non-oop mem input"); |
| } else if (base != fp || offset == Type::OffsetBot) { |
| // Do nothing: the fp operand is either not from a memory use |
| // (base == NULL) OR the fp is used in a non-memory context |
| // (base is some other register) OR the offset is not constant, |
| // so it is not a stack slot. |
| } else { |
| assert(offset >= 0, "unexpected negative offset"); |
| offset -= (offset % jintSize); // count the whole word |
| int stack_reg = regalloc->offset2reg(offset); |
| if (OptoReg::is_stack(stack_reg)) { |
| set_live_bit(tmp_live, stack_reg); |
| } else { |
| assert(false, "stack_reg not on stack?"); |
| } |
| } |
| } |
| } |
| |
| if( n->jvms() ) { // Record liveness at safepoint |
| |
| // This placement of this stanza means inputs to calls are |
| // considered live at the callsite's OopMap. Argument oops are |
| // hence live, but NOT included in the oopmap. See cutout in |
| // build_oop_map. Debug oops are live (and in OopMap). |
| int *n_live = NEW_ARENA_ARRAY(A, int, max_reg_ints); |
| for( int l=0; l<max_reg_ints; l++ ) |
| n_live[l] = tmp_live[l]; |
| safehash->Insert(n,n_live); |
| } |
| |
| } |
| |
| // Now at block top, see if we have any changes. If so, propagate |
| // to prior blocks. |
| int *old_live = &live[b->_pre_order*max_reg_ints]; |
| int l; |
| for( l=0; l<max_reg_ints; l++ ) |
| if( tmp_live[l] != old_live[l] ) |
| break; |
| if( l<max_reg_ints ) { // Change! |
| // Copy in new value |
| for( l=0; l<max_reg_ints; l++ ) |
| old_live[l] = tmp_live[l]; |
| // Push preds onto worklist |
| for (l = 1; l < (int)b->num_preds(); l++) { |
| Block* block = cfg->get_block_for_node(b->pred(l)); |
| worklist->push(block); |
| } |
| } |
| } |
| |
| // Scan for any missing safepoints. Happens to infinite loops |
| // ala ZKM.jar |
| uint i; |
| for (i = 1; i < cfg->number_of_blocks(); i++) { |
| Block* block = cfg->get_block(i); |
| uint j; |
| for (j = 1; j < block->number_of_nodes(); j++) { |
| if (block->get_node(j)->jvms() && (*safehash)[block->get_node(j)] == NULL) { |
| break; |
| } |
| } |
| if (j < block->number_of_nodes()) { |
| break; |
| } |
| } |
| if (i == cfg->number_of_blocks()) { |
| break; // Got 'em all |
| } |
| #ifndef PRODUCT |
| if( PrintOpto && Verbose ) |
| tty->print_cr("retripping live calc"); |
| #endif |
| // Force the issue (expensively): recheck everybody |
| for (i = 1; i < cfg->number_of_blocks(); i++) { |
| worklist->push(cfg->get_block(i)); |
| } |
| } |
| } |
| |
| // Collect GC mask info - where are all the OOPs? |
| void Compile::BuildOopMaps() { |
| NOT_PRODUCT( TracePhase t3("bldOopMaps", &_t_buildOopMaps, TimeCompiler); ) |
| // Can't resource-mark because I need to leave all those OopMaps around, |
| // or else I need to resource-mark some arena other than the default. |
| // ResourceMark rm; // Reclaim all OopFlows when done |
| int max_reg = _regalloc->_max_reg; // Current array extent |
| |
| Arena *A = Thread::current()->resource_area(); |
| Block_List worklist; // Worklist of pending blocks |
| |
| int max_reg_ints = round_to(max_reg, BitsPerInt)>>LogBitsPerInt; |
| Dict *safehash = NULL; // Used for assert only |
| // Compute a backwards liveness per register. Needs a bitarray of |
| // #blocks x (#registers, rounded up to ints) |
| safehash = new Dict(cmpkey,hashkey,A); |
| do_liveness( _regalloc, _cfg, &worklist, max_reg_ints, A, safehash ); |
| OopFlow *free_list = NULL; // Free, unused |
| |
| // Array mapping blocks to completed oopflows |
| OopFlow **flows = NEW_ARENA_ARRAY(A, OopFlow*, _cfg->number_of_blocks()); |
| memset( flows, 0, _cfg->number_of_blocks() * sizeof(OopFlow*) ); |
| |
| |
| // Do the first block 'by hand' to prime the worklist |
| Block *entry = _cfg->get_block(1); |
| OopFlow *rootflow = OopFlow::make(A,max_reg,this); |
| // Initialize to 'bottom' (not 'top') |
| memset( rootflow->_callees, OptoReg::Bad, max_reg*sizeof(short) ); |
| memset( rootflow->_defs , 0, max_reg*sizeof(Node*) ); |
| flows[entry->_pre_order] = rootflow; |
| |
| // Do the first block 'by hand' to prime the worklist |
| rootflow->_b = entry; |
| rootflow->compute_reach( _regalloc, max_reg, safehash ); |
| for( uint i=0; i<entry->_num_succs; i++ ) |
| worklist.push(entry->_succs[i]); |
| |
| // Now worklist contains blocks which have some, but perhaps not all, |
| // predecessors visited. |
| while( worklist.size() ) { |
| // Scan for a block with all predecessors visited, or any randoms slob |
| // otherwise. All-preds-visited order allows me to recycle OopFlow |
| // structures rapidly and cut down on the memory footprint. |
| // Note: not all predecessors might be visited yet (must happen for |
| // irreducible loops). This is OK, since every live value must have the |
| // SAME reaching def for the block, so any reaching def is OK. |
| uint i; |
| |
| Block *b = worklist.pop(); |
| // Ignore root block |
| if (b == _cfg->get_root_block()) { |
| continue; |
| } |
| // Block is already done? Happens if block has several predecessors, |
| // he can get on the worklist more than once. |
| if( flows[b->_pre_order] ) continue; |
| |
| // If this block has a visited predecessor AND that predecessor has this |
| // last block as his only undone child, we can move the OopFlow from the |
| // pred to this block. Otherwise we have to grab a new OopFlow. |
| OopFlow *flow = NULL; // Flag for finding optimized flow |
| Block *pred = (Block*)0xdeadbeef; |
| // Scan this block's preds to find a done predecessor |
| for (uint j = 1; j < b->num_preds(); j++) { |
| Block* p = _cfg->get_block_for_node(b->pred(j)); |
| OopFlow *p_flow = flows[p->_pre_order]; |
| if( p_flow ) { // Predecessor is done |
| assert( p_flow->_b == p, "cross check" ); |
| pred = p; // Record some predecessor |
| // If all successors of p are done except for 'b', then we can carry |
| // p_flow forward to 'b' without copying, otherwise we have to draw |
| // from the free_list and clone data. |
| uint k; |
| for( k=0; k<p->_num_succs; k++ ) |
| if( !flows[p->_succs[k]->_pre_order] && |
| p->_succs[k] != b ) |
| break; |
| |
| // Either carry-forward the now-unused OopFlow for b's use |
| // or draw a new one from the free list |
| if( k==p->_num_succs ) { |
| flow = p_flow; |
| break; // Found an ideal pred, use him |
| } |
| } |
| } |
| |
| if( flow ) { |
| // We have an OopFlow that's the last-use of a predecessor. |
| // Carry it forward. |
| } else { // Draw a new OopFlow from the freelist |
| if( !free_list ) |
| free_list = OopFlow::make(A,max_reg,C); |
| flow = free_list; |
| assert( flow->_b == NULL, "oopFlow is not free" ); |
| free_list = flow->_next; |
| flow->_next = NULL; |
| |
| // Copy/clone over the data |
| flow->clone(flows[pred->_pre_order], max_reg); |
| } |
| |
| // Mark flow for block. Blocks can only be flowed over once, |
| // because after the first time they are guarded from entering |
| // this code again. |
| assert( flow->_b == pred, "have some prior flow" ); |
| flow->_b = NULL; |
| |
| // Now push flow forward |
| flows[b->_pre_order] = flow;// Mark flow for this block |
| flow->_b = b; |
| flow->compute_reach( _regalloc, max_reg, safehash ); |
| |
| // Now push children onto worklist |
| for( i=0; i<b->_num_succs; i++ ) |
| worklist.push(b->_succs[i]); |
| |
| } |
| } |
